Textile properties of synthetic prolapse mesh in response to uniaxial loading.

PubMed

Barone, William R; Moalli, Pamela A; Abramowitch, Steven D

2016-09-01

Although synthetic mesh is associated with superior anatomic outcomes for the repair of pelvic organ prolapse, the benefits of mesh have been questioned because of the relatively high complication rates. To date, the mechanisms that result in such complications are poorly understood, yet the textile characteristics of mesh products are believed to play an important role. Interestingly, the pore diameter of synthetic mesh has been shown to impact the host response after hernia repair greatly, and such findings have served as design criteria for prolapse meshes, with larger pores viewed as more favorable. Although pore size and porosity are well-characterized before implantation, the changes in these textile properties after implantation are unclear; the application of mechanical forces has the potential to greatly alter pore geometries in vivo. Understanding the impact of mechanical loading on the textile properties of mesh is essential for the development of more effective devices for prolapse repair. The objective of this study was to determine the effect of tensile loading and pore orientation on mesh porosity and pore dimensions. In this study, the porosity and pore diameter of 4 currently available prolapse meshes were examined in response to uniaxial tensile loads of 0.1, 5, and 10 N while mimicking clinical loading conditions. The textile properties were compared with those observed for the unloaded mesh. Meshes included Gynemesh PS (Ethicon, Somerville, NJ), UltraPro (Artisyn; Ethicon), Restorelle (Coloplast, Minneapolis, MN), and Alyte Y-mesh (Bard, Covington, GA). In addition to the various pore geometries, 3 orientations of Restorelle (0-, 5-, 45-degree offset) and 2 orientations of UltraPro (0-, 90-degree offset) were examined. In response to uniaxial loading, both porosity and pore diameter dramatically decreased for most mesh products. The application of 5 N led to reductions in porosity for nearly all groups, with values decreasing by as much as 87% (P < .05). On loading to 10 N of force, nearly all mesh products that were tested were found to have porosities that approached 0% and 0 pores with diameters >1 mm. In this study, it was shown that the pore size of current prolapse meshes dramatically decreases in response to mechanical loading. These findings suggest that prolapse meshes, which are more likely to experience tensile forces in vivo relative to hernia repair meshes, have pores that are unfavorable for tissue integration after surgical tensioning and/or loading in urogynecologic surgeries. Such decreases in pore geometry support the hypothesis that regional increases in the concentration of mesh leads to an enhanced local foreign body response. Although pore deformation in transvaginal meshes requires further characterization, the findings presented here provide a mechanical understanding that can be used to recognize potential areas of concern for complex mesh geometries. Understanding mesh mechanics in response to surgical and in vivo loading conditions may provide improved design criteria for mesh and a refinement of surgical techniques, ultimately leading to better patient outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Biologic meshes are not superior to synthetic meshes in ventral hernia repair: an experimental study with long-term follow-up evaluation.

PubMed

Ditzel, M; Deerenberg, E B; Grotenhuis, N; Harlaar, J J; Monkhorst, K; Bastiaansen-Jenniskens, Y M; Jeekel, J; Lange, J F

2013-10-01

In laparoscopic incisional hernia repair, direct contact between the prosthesis and the abdominal viscera is inevitable, which may lead to an inflammatory reaction resulting in abdominal adhesion formation. This study compared five different synthetic and biologic meshes in terms of adhesion formation, shrinkage, incorporation, and histologic characteristics after a period of 30 and 90 days. In 85 rats, a mesh was positioned intraperitoneally in direct contact with the viscera. Five different meshes were implanted: Prolene (polypropylene), Parietex composite (collagen-coated polyester), Strattice (porcine dermis, non-cross-linked), Surgisis (porcine small intestine submucosa, non-cross-linked), and Permacol (porcine dermis, cross-linked). The meshes were tested in terms of adhesion formation, shrinkage, and incorporation after a period of 30 and 90 days. Additionally, collagen formation after 90 days was determined. Significantly less adhesion formation was observed with Parietex composite (5 %; interquartile range [IQR], 2-5 %) and Strattice (5 %; IQR, 4-10 %) in the long term. In contrast, organs were attached to Permacol with four of seven meshes (57 %), and adhesion coverage of Surgisis mesh was present in 66 % (IQR, 0-100 %) of the cases. After 90 days, the best incorporation was seen with the Parietex composite mesh (79 %; IQR, 61-83 %). After 90 days, major alterations in adhesion formation were seen compared with 30 days. Histologically, Strattice and Parietex composite showed a new mesothelial layer on the visceral side of the mesh. Microscopic degradation and new collagen formation were seen in the Surgisis group. Parietex composite mesh demonstrated the best long-term results compared with all the other meshes. The biologic non-cross-linked mesh, Strattice, showed little adhesion formation and moderate shrinkage but poor incorporation. Biologic meshes are promising, but varying results require a more detailed investigation and demonstrate that biologic meshes are not necessarily superior to synthetic meshes. The significant changes that take place between 30 and 90 days should lead to careful interpretation of short-term experimental results.

Pelvic organ prolapse (POP) surgery: the evidence for the repairs.

PubMed

Gomelsky, Alex; Penson, David F; Dmochowski, Roger R

2011-06-01

What is known on the subject? and What does the study add? Substantial experience of the outcomes has been gathered regarding the acute and sub-acute experience with various types of corrective procedures for POP. These include long-term POP correction as well as more recent recognition of improvement in functional disorders associated with POP such as UI, colorectal dysfunction, and sexual dysfunction. Long-term follow-up is available for some of the older types of interventions and current multicentre trials are being accrued with longer term follow-up for new interventions including mesh-type repairs. The study adds a condensed and summarized version of the current literature regarding the various interventions for POP and also provides an overview of the current controversies and areas where knowledge is incomplete and in need of further elaboration for definitive answers regarding optimization of surgical care for POP. Our aim is to summarise the available data on the transvaginal placement of synthetic mesh for pelvic organ prolapse (POP) repair, with a focus on the outcomes and complications of commercial POP-repair kits. As the stability and durability of autologous tissues may be questionable, nonabsorbable, synthetic materials are an attractive alternative for providing additional support during POP surgery. These materials are not novel, and most have been used for many years in surgical applications, e.g. hernia repairs. While theoretically appealing, the implantation of synthetic mesh in the pelvis may be associated with inherent adverse consequences, such as erosion, extrusion, and infection. Additionally, the routine use of these materials may carry potential long-term complications, such as dyspareunia, chronic pelvic pain, and vaginal distortion. The success and failure of mesh-augmented POP repair is related not only to the synthetic material itself, but also to patient- and surgeon-related factors. Recent warnings by the USA Food and Drug Administration and other groups regarding adverse events further complicate the decision to use synthetic mesh. © 2011 THE AUTHORS; BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

The IUGA/ICS classification of synthetic mesh complications in female pelvic floor reconstructive surgery: a multicenter study.

PubMed

Miklos, John R; Chinthakanan, Orawee; Moore, Robert D; Mitchell, Gretchen K; Favors, Sheena; Karp, Deborah R; Northington, Gina M; Nogueiras, Gladys M; Davila, G Willy

2016-06-01

The objective was to report patterns of sling and transvaginal mesh-related complications using the IUGA/ICS classification of prosthesis-related complications. This was a retrospective chart review of all patients who underwent surgical removal of sling, transvaginal mesh, and sacrocolpopexy for mesh-related complications from 2011 to 2013 at three tertiary referral centers. The International Urogynecological Association (IUGA)/International Continence Society (ICS) classification system was utilized. We identified 445 patients with mesh complications, 506 pieces of synthetic mesh were removed, and 587 prostheses-related complications were classified. 3.7 % of patients had viscus organ penetration or vaginal exposure as their presenting chief complaint and 59.7 % were classified as not having any vaginal epithelial separation or category 1. The most common category was spontaneous pain (1Be: 32.5 %) followed by dyspareunia (1Bc: 14.7 %). The sling group was 20 % more likely to have pain compared with the pelvic organ prolapse (POP) mesh group (OR 1.2, 95 % CI 0.8-1.6). The most commonly affected site (S2) was away from the suture line (49 %). Compared with the sling group, the POP group had a higher rate of mesh exposure, which mostly occurred at the suture line area. The majority of patients presented with mesh-related complications more than 1 year post-insertion (T4; average 3.68 ± 2.47 years). Surgeons should be aware that patients with vaginal mesh complications routinely exhibit complications more than 1 year after the implantation with pain as the most common presenting symptom.

Mesh Nanoelectronics: Seamless Integration of Electronics with Tissues.

PubMed

Dai, Xiaochuan; Hong, Guosong; Gao, Teng; Lieber, Charles M

2018-02-20

Nanobioelectronics represents a rapidly developing field with broad-ranging opportunities in fundamental biological sciences, biotechnology, and medicine. Despite this potential, seamless integration of electronics has been difficult due to fundamental mismatches, including size and mechanical properties, between the elements of the electronic and living biological systems. In this Account, we discuss the concept, development, key demonstrations, and future opportunities of mesh nanoelectronics as a general paradigm for seamless integration of electronics within synthetic tissues and live animals. We first describe the design and realization of hybrid synthetic tissues that are innervated in three dimensions (3D) with mesh nanoelectronics where the mesh serves as both as a tissue scaffold and as a platform of addressable electronic devices for monitoring and manipulating tissue behavior. Specific examples of tissue/nanoelectronic mesh hybrids highlighted include 3D neural tissue, cardiac patches, and vascular constructs, where the nanoelectronic devices have been used to carry out real-time 3D recording of electrophysiological and chemical signals in the tissues. This novel platform was also exploited for time-dependent 3D spatiotemporal mapping of cardiac tissue action potentials during cell culture and tissue maturation as well as in response to injection of pharmacological agents. The extension to simultaneous real-time monitoring and active control of tissue behavior is further discussed for multifunctional mesh nanoelectronics incorporating both recording and stimulation devices, providing the unique capability of bidirectional interfaces to cardiac tissue. In the case of live animals, new challenges must be addressed, including minimally invasive implantation, absence of deleterious chronic tissue response, and long-term capability for monitoring and modulating tissue activity. We discuss each of these topics in the context of implantation of mesh nanoelectronics into rodent brains. First, we describe the design of ultraflexible mesh nanoelectronics with size features and mechanical properties similar to brain tissue and a novel syringe-injection methodology that allows the mesh nanoelectronics to be precisely delivered to targeted brain regions in a minimally invasive manner. Next, we discuss time-dependent histology studies showing seamless and stable integration of mesh nanoelectronics within brain tissue on at least one year scales without evidence of chronic immune response or glial scarring characteristic of conventional implants. Third, armed with facile input/output interfaces, we describe multiplexed single-unit recordings that demonstrate stable tracking of the same individual neurons and local neural circuits for at least 8 months, long-term monitoring and stimulation of the same groups of neurons, and following changes in individual neuron activity during brain aging. Moving forward, we foresee substantial opportunities for (1) continued development of mesh nanoelectronics through, for example, broadening nanodevice signal detection modalities and taking advantage of tissue-like properties for selective cell targeting and (2) exploiting the unique capabilities of mesh nanoelectronics for tackling critical scientific and medical challenges such as understanding and potentially ameliorating cell and circuit level changes associated with natural and pathological aging, as well as using mesh nanoelectronics as active tissue scaffolds for regenerative medicine and as neuroprosthetics for monitoring and treating neurological diseases.

Anterior pelvic organ prolapse repair using synthetic mesh.

PubMed

Patel, Bhavin N; Lucioni, Alvaro; Kobashi, Kathleen C

2012-06-01

Since the U.S. Food and Drug Administration (FDA) statement on mesh in July of 2011, there has been controversy regarding synthetic mesh repairs for vaginal prolapse. In this article, we review the biochemical basis for the use of synthetic mesh in prolapse repair as well as clinical results of anterior compartment prolapse repair with synthetic mesh. Finally, we discuss the FDA warning regarding mesh.

Structural differences and architectural features of two different polypropylene slings (TVT-O and I-STOP) have no impact on biocompatibility and tissue reactions

PubMed Central

Przydacz, Mikolaj; Adli, Oussama El Yazami; Mahfouz, Wally; Loutochin, Oleg; Bégin, Louis R.

2017-01-01

Introduction To evaluate the impact of design features of the synthetic mid-urethral slings on tissue integrity and inflammatory responses. Material and methods In total 30 female Sprague-Dawley rats were implanted with type I monofilamentous, macroporous polypropylene meshes: Gynecare TVT-Obturator tape® (Ethicon Inc., Johnson & Johnson, Somerville, NJ, USA) and I-STOP® (CL Medical Inc., Lyon, France). All animal groups were sacrificed at set time intervals – 6 weeks, 3 months, 6 months, 9 months and 12 months – and the abdominal wall was harvested with mesh strips for histological evaluation. Results All mesh strips appeared to be well incorporated into the abdominal wall, and no signs of shrinkage was noticed. All specimens showed a thin/delicate, loose, fibrous interface between the synthetic graft plate and abdominal wall, along with mild inflammatory reactions from 6 weeks to 12 months. Conclusions Both mesh brands induced comparable, minimal foreign body reactions and integrated well into the host tissues despite differences in architectural features. TVT-O® and I-STOP® evoked similar low-grade inflammatory responses up to 12 months in this animal model. Structural differences and architectural features of polypropylene slings used in this study have had no impact on tissue integrity and inflammatory responses. PMID:28721282

Structural differences and architectural features of two different polypropylene slings (TVT-O and I-STOP) have no impact on biocompatibility and tissue reactions.

PubMed

Przydacz, Mikolaj; Adli, Oussama El Yazami; Mahfouz, Wally; Loutochin, Oleg; Bégin, Louis R; Corcos, Jacques

2017-06-30

To evaluate the impact of design features of the synthetic mid-urethral slings on tissue integrity and inflammatory responses. In total 30 female Sprague-Dawley rats were implanted with type I monofilamentous, macroporous polypropylene meshes: Gynecare TVT-Obturator tape ® (Ethicon Inc., Johnson & Johnson, Somerville, NJ, USA) and I-STOP ® (CL Medical Inc., Lyon, France). All animal groups were sacrificed at set time intervals - 6 weeks, 3 months, 6 months, 9 months and 12 months - and the abdominal wall was harvested with mesh strips for histological evaluation. All mesh strips appeared to be well incorporated into the abdominal wall, and no signs of shrinkage was noticed. All specimens showed a thin/delicate, loose, fibrous interface between the synthetic graft plate and abdominal wall, along with mild inflammatory reactions from 6 weeks to 12 months. Both mesh brands induced comparable, minimal foreign body reactions and integrated well into the host tissues despite differences in architectural features. TVT-O ® and I-STOP ® evoked similar low-grade inflammatory responses up to 12 months in this animal model. Structural differences and architectural features of polypropylene slings used in this study have had no impact on tissue integrity and inflammatory responses.

The scientific basis for the use of biomaterials in stress urinary incontinence (SUI) and pelvic organ prolapse (POP).

PubMed

Colaco, Marc; Mettu, Jayadev; Badlani, Gopal

2015-06-01

To review the scientific and clinical literature to assess the basis for the use of biomaterials in stress urinary incontinence (SUI) and pelvic organ prolapse (POP). Pelvic floor diseases (PFDS), such as SUI and POP, are common and vexing disorders. While synthetic mesh-based repairs have long been considered an option for PFD treatment, and their efficacy established in randomised clinical trials, safety of its use has recently been called into question. Using the PubMed, MEDLINE and Medical Subject Headings (MeSH) databases, we performed a critical review of English-language publications that contained the following keywords: 'pelvic organ prolapse', 'stress urinary incontinence', 'mesh', 'biomaterial', 'collagen', 'elastin' and 'extracellular matrix'. After reviewing for relevance for mesh use in the pelvis by two independent reviewers with a third available in the case of disagreement, a total of 60 articles were included in the present review. We found that many of the potential causes of PFDs are due to altered metabolism of patient extracellular matrix (specifically collagen, elastin, and their respective enzymes) and as such, repairs using native tissue may suffer from the same abnormalities leading to a subsequent lack of repair integrity. However, mesh use is not without its unique risks. Several publications have suggested that biomaterials may undergo alteration after implantation, but these findings have not been demonstrated in the normal milieu. While the decision for the use of synthetic mesh is scientifically sound, its benefits and risks must be discussed with the patient in an informed decision-making process. © 2014 The Authors. BJU International © 2014 BJU International.

Tissue response to collagen containing polypropylene meshes in an ovine vaginal repair model.

PubMed

Darzi, Saeedeh; Urbankova, Iva; Su, Kai; White, Jacinta; Lo, Camden; Alexander, David; Werkmeister, Jerome A; Gargett, Caroline E; Deprest, Jan

2016-07-15

Pelvic Organ Prolapse (POP) is the herniation of pelvic organs into the vagina. Despite broad acceptance of mesh use in POP surgical repair, the complication rate is unacceptable. We hypothesized that collagen-containing polypropylene (PP) mesh types could modulate mesh-tissue integration and reduce long-term inflammation, thereby reducing mesh-associated complications. This study compared the long-term tissue response to an unmodified PP mesh and two collagen containing meshes in an ovine model which has similar pelvic anatomy and vaginal size to human. Three commercially available macroporous PP meshes, uncoated PP mesh (Avaulta Solo) (PP), the same textile PP mesh layered with a sheet of cross-linked porcine acellular matrix (Avaulta Plus) (PP-ACM) and a different yet also macroporous PP (Sofradim) mesh coated with solubilized atelocollagen (Ugytex) (PP-sCOL) were implanted in the ovine vagina and tissue explanted after 60 and 180days. The macrophage phenotype and response to implanted meshes, and vascularity were quantified by immunostaining and morphometry. We quantified changes in extracellular matrix composition biochemically and collagen organisation and percentage area around the interface of the mesh implants by Sirius Red birefringence and morphometry. PP-ACM induced a more sustained inflammatory response, indicated by similar CD45(+) leukocytes but reduced CD163(+) M2 macrophages at 60days (P<0.05). PP-sCOL increased Von Willebrand Factor (vWF)-immunoreactive vessel profiles after 60days. At the micro-molecular level, collagen birefringence quantification revealed significantly fewer mature collagen fibrils (red, thick fibrils) at the mesh-tissue interface than control tissue for all mesh types (P<0.001) but still significantly greater than the proportion of immature (green thin fibrils) at 60days (P<0.05). The proportion of mature collagen fibrils increased with time around the mesh filaments, particularly those containing collagen. The total collagen percent area at the mesh interface was greatest around the PP-ACM mesh at 60days (P<0.05). By 180days the total mature and immature collagen fibres at the interface of the mesh filaments resembled that of native tissue. In particular, these results suggest that both meshes containing collagen evoke different types of tissue responses at different times during the healing response yet both ultimately lead to physiological tissue formation approaching that of normal tissue. Pelvic organ prolapse (POP) is the descent of the pelvic organs to the vagina. POP affects more than 25% of all women and the lifetime risk of undergoing POP surgery is 19%. Although synthetic polypropylene (PP) meshes have improved the outcome of the surgical treatment for POP, there was an unacceptable rate of adverse events including mesh exposure and contracture. It is hypothesized that coating the PP meshes with collagen would provide a protective effect by preventing severe mesh adhesions to the wound, resulting in a better controlled initial inflammatory response, and diminished risk of exposure. In this study we assessed the effect of two collagen-containing PP meshes on the long-term vaginal tissue response using new techniques to quantify these tissue responses. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Preventing Mesh Pore Collapse by Designing Mesh Pores With Auxetic Geometries: A Comprehensive Evaluation Via Computational Modeling.

PubMed

Knight, Katrina M; Moalli, Pamela A; Abramowitch, Steven D

2018-05-01

Pelvic organ prolapse (POP) meshes are exposed to predominately tensile loading conditions in vivo that can lead to pore collapse by 70-90%, decreasing overall porosity and providing a plausible mechanism for the contraction/shrinkage of mesh observed following implantation. To prevent pore collapse, we proposed to design synthetic meshes with a macrostructure that results in auxetic behavior, the pores expand laterally, instead of contracting when loaded. Such behavior can be achieved with a range of auxetic structures/geometries. This study utilized finite element analysis (FEA) to assess the behavior of mesh models with eight auxetic pore geometries subjected to uniaxial loading to evaluate their potential to allow for pore expansion while simultaneously providing resistance to tensile loading. Overall, substituting auxetic geometries for standard pore geometries yielded more pore expansion, but often at the expense of increased model elongation, with two of the eight auxetics not able to maintain pore expansion at higher levels of tension. Meshes with stable pore geometries that remain open with loading will afford the ingrowth of host tissue into the pores and improved integration of the mesh. Given the demonstrated ability of auxetic geometries to allow for pore size maintenance (and pore expansion), auxetically designed meshes have the potential to significantly impact surgical outcomes and decrease the likelihood of major mesh-related complications.

Association Between the Amount of Vaginal Mesh Used With Mesh Erosions and Repeated Surgery After Repairing Pelvic Organ Prolapse and Stress Urinary Incontinence.

PubMed

Chughtai, Bilal; Barber, Matthew D; Mao, Jialin; Forde, James C; Normand, Sharon-Lise T; Sedrakyan, Art

2017-03-01

Mesh, a synthetic graft, has been used in pelvic organ prolapse (POP) repair and stress urinary incontinence (SUI) to augment and strengthen weakened tissue. Polypropylene mesh has come under scrutiny by the US Food and Drug Administration. To examine the rates of mesh complications and invasive reintervention after the placement of vaginal mesh for POP repair or SUI surgery. This investigation was an observational cohort study at inpatient and ambulatory surgery settings in New York State. Participants were women who underwent transvaginal repair for POP or SUI with mesh between January 1, 2008, and December 31, 2012, and were followed up through December 31, 2013. They were divided into the following 4 groups based on the amount of mesh exposure: transvaginal POP repair surgery with mesh and concurrent sling use (vaginal mesh plus sling group), transvaginal POP repair with mesh and no concurrent sling use (vaginal mesh group), transvaginal POP repair without mesh but concurrent sling use for SUI (POP sling group), and sling for SUI alone (SUI sling group). The primary outcome was the occurrence of mesh complications and repeated invasive intervention within 1 year after the initial mesh implantation. A time-to-event analysis was performed to examine the occurrence of mesh erosions and subsequent reintervention. Secondary analyses of an age association (<65 vs ≥65 years) were conducted. The study identified 41 604 women who underwent 1 of the 4 procedures. The mean (SD) age of women at their initial mesh implantation was 56.2 (13.0) years. The highest risk of erosions was found in the vaginal mesh plus sling group (2.72%; 95% CI, 2.31%-3.21%) and the lowest in the SUI sling group (1.57%; 95% CI, 1.41%-1.74%). The risk of repeated surgery with concomitant erosion diagnosis was also the highest in the vaginal mesh plus sling group (2.13%; 95% CI, 1.76%-2.56%) and the lowest in the SUI sling group (1.16%; 95% CI, 1.03%-1.31%). The combined use of POP mesh and SUI mesh sling was associated with the highest erosion and repeated intervention risk, while mesh sling alone had the lowest erosion and repeated intervention risk. There is evidence for a dose-response relationship between the amount of mesh used and subsequent mesh erosions, complications, and invasive repeated intervention.

Laparoscopic-assisted tension-free vaginal mesh: an innovative approach to placing synthetic mesh: transvaginally for surgical correction of pelvic organ prolapse.

PubMed

Watanabe, Toyohiko; Inoue, Miyabi; Ishii, Ayano; Yamato, Toyoko; Yamamoto, Masumi; Sasaki, Katsumi; Kobayashi, Yasuyuki; Araki, Motoo; Uehara, Shinya; Saika, Takashi; Kumon, Hiromi

2012-01-01

Polypropylene mesh implants for the correction of pelvic organ prolapse (POP) are now available in Japan. We developed an innovative approach for correcting POP by placing polypropylene mesh transvaginally with laparoscopic assistance. From June 2007 through March 2010, sixteen consecutive patients with symptomatic stage 2 or 3 pelvic organ prolapse underwent the laparoscopic-assisted tension-free vaginal mesh procedure at Okayama University Hospital. All patients were evaluated before and at 1, 3, 6, and 12 months after surgery. Female sexual function was also evaluated with the Female Sexual Function Index (FSFI). The procedure was performed successfully without significant complications. Fifteen of 16 patients were considered anatomically cured (93.8%) at 12 months postoperatively. One patient with a recurrent stage 3 vaginal vault prolapse required sacral colpopexy six months postoperatively. Total FSFI scores improved significantly from 10.3 ± 1.3 at baseline to 18.0 ± 1.2 at 12 months after surgery. The laparoscopic-assisted trans-vaginal mesh is a safe, effective, and simple procedure for POP repairs. The procedure not only restores anatomic relationships but also improves sexual function.

Impact of the 2011 FDA transvaginal mesh safety update on AUGS members' use of synthetic mesh and biologic grafts in pelvic reconstructive surgery.

PubMed

Clemons, Jeffrey L; Weinstein, Milena; Guess, Marsha K; Alperin, Marianna; Moalli, Pamela; Gregory, William Thomas; Lukacz, Emily S; Sung, Vivian W; Chen, Bertha H; Bradley, Catherine S

2013-01-01

To describe the frequency of use and recent change in use of synthetic mesh and biologic grafts in pelvic organ prolapse (POP) and stress urinary incontinence surgery by American Urogynecology Society (AUGS) members. An electronic survey of AUGS members was conducted between December 2011 and January 2012. Frequency of graft use in POP (overall and by transvaginal and transabdominal approaches) and stress urinary incontinence surgery was queried relative to the timing of the 2011 Food and Drug Administration (FDA) safety update. Rates of materials' use before and after the statement were compared using Wilcoxon signed rank test. Fifty-three percent (507/962) of AUGS members responded and were included in analysis; 79% were urogynecologists. Before the FDA warning, in POP surgery, most (90%) used synthetic mesh and fewer (34%) used biologic grafts; 99% used synthetic mesh slings. After the FDA statement, respondents reported an overall decrease in the percent of POP cases in which they used synthetic mesh (P < 0.001) but no change in biologic graft use for POP (P = 0.37) or synthetic mesh sling use (P = 0.10). Specifically, transvaginal mesh use decreased: 40% reported decreased use and 12% stopped use. However, transvaginal mesh was still used by 61% of respondents in at least some cases. No change (62%) or increased use (12%) of mesh was reported for transabdominal POP procedures. Synthetic mesh use in transvaginal POP surgery decreased after the 2011 FDA safety update, but synthetic mesh use for transabdominal POP repair and sling procedures and overall biologic graft use in POP surgery did not decrease.

The foreign body response: at the interface of surgery and bioengineering.

PubMed

Major, Melanie R; Wong, Victor W; Nelson, Emily R; Longaker, Michael T; Gurtner, Geoffrey C

2015-05-01

The surgical implantation of materials and devices has dramatically increased over the past decade. This trend is expected to continue with the broadening application of biomaterials and rapid expansion of aging populations. One major factor that limits the potential of implantable materials and devices is the foreign body response, an immunologic reaction characterized by chronic inflammation, foreign body giant cell formation, and fibrotic capsule formation. The English literature on the foreign body response to implanted materials and devices is reviewed. Fibrotic encapsulation can cause device malfunction and dramatically limit the function of an implanted medical device or material. Basic science studies suggest a role for immune and inflammatory pathways at the implant-host interface that drive the foreign body response. Current strategies that aim to modulate the host response and improve construct biocompatibility appear promising. This review article summarizes recent basic science, preclinical, and clinicopathologic studies examining the mechanisms driving the foreign body response, with particular focus on breast implants and synthetic meshes. Understanding these molecular and cellular mechanisms will be critical for achieving the full potential of implanted biomaterials to restore human tissues and organs.

Alveolar Ridge Reconstruction with Titanium Meshes and Simultaneous Implant Placement: A Retrospective, Multicenter Clinical Study

PubMed Central

Paraud Freixas, Andres; Han, Chang-Hun; Bechara, Sohueil; Tawil, Isaac

2016-01-01

Objective. To evaluate horizontal bone gain and implant survival and complication rates in patients treated with titanium meshes placed simultaneously with dental implants and fixed over them. Methods. Twenty-five patients treated with 40 implants and simultaneous guided bone regeneration with titanium meshes (i–Gen®, MegaGen, Gyeongbuk, Republic of Korea) were selected for inclusion in the present retrospective multicenter study. Primary outcomes were horizontal bone gain and implant survival; secondary outcomes were biological and prosthetic complications. Results. After the removal of titanium meshes, the CBCT evaluation revealed a mean horizontal bone gain of 3.67 mm (±0.89). The most frequent complications were mild postoperative edema (12/25 patients: 48%) and discomfort after surgery (10/25 patients: 40%); these complications were resolved within one week. Titanium mesh exposure occurred in 6 patients (6/25 : 24%): one of these suffered partial loss of the graft and another experienced complete graft loss and implant failure. An implant survival rate of 97.5% (implant-based) and a peri-implant marginal bone loss of 0.43 mm (±0.15) were recorded after 1 year. Conclusions. The horizontal ridge reconstruction with titanium meshes placed simultaneously with dental implants achieved predictable satisfactory results. Prospective randomized controlled trials on a larger sample of patients are required to validate these positive outcomes. PMID:27999799

Surgical meshes coated with mesenchymal stem cells provide an anti-inflammatory environment by a M2 macrophage polarization.

PubMed

Blázquez, Rebeca; Sánchez-Margallo, Francisco Miguel; Álvarez, Verónica; Usón, Alejandra; Casado, Javier G

2016-02-01

Surgical meshes are widely used in clinics to reinforce soft tissue's defects, and to give support to prolapsed organs. However, the implantation of surgical meshes is commonly related with an inflammatory response being difficult to eradicate without removing the mesh. Here we hypothesize that the combined use of surgical meshes and mesenchymal stem cells (MSCs) could be a useful tool to reduce the inflammatory reaction secondary to mesh implantation. In vitro determinations of viability, metabolic activity and immunomodulation assays were performed on MSCs-coated meshes. Magnetic resonance imaging, evaluation by laparoscopic optical system and histology were performed for safety assessment. Finally, flow cytometry and qRT-PCR were used to elucidate the mechanism of action of MSCs-coated meshes. Our results demonstrate the feasibility to obtain MSCs-coated surgical meshes and their cryopreservability to be used as an 'off the shelf' product. These biological meshes fulfill the safety aspects as non-adverse effects were observed when compared to controls. Moreover, both in vitro and in vivo studies demonstrated that, local immunomodulation of implanted meshes is mediated by a macrophage polarization towards an anti-inflammatory phenotype. In conclusion, the combined usage of surgical meshes with MSCs fulfills the safety requirements for a future clinical application, providing an anti-inflammatory environment that could reduce the inflammatory processes commonly observed after surgical mesh implantation. Surgical meshes are medical devices widely used in clinics to resolve hernias and organs' prolapses, among other disorders. However, the implantation of surgical meshes is commonly related with an inflammatory response being difficult to eradicate without removing the mesh, causing pain and discomfort in the patient. Previously, the anti-inflammatory, immunomodulatory and pro-regenerative ability of mesenchymal stem cells (MSCs) have been described. To our knowledge, this is the first report where the anti-inflammatory and pro-regenerative ability of MSCs have been successfully applied in combination with surgical meshes, reducing the inflammatory processes commonly observed after mesh implantation. Moreover, our in vitro and in vivo results highlight the safety and efficacy of these bioactive meshes as a 'ready to use' medical product. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Polycaprolactone electrospun mesh conjugated with an MSC affinity peptide for MSC homing in vivo.

PubMed

Shao, Zhenxing; Zhang, Xin; Pi, Yanbin; Wang, Xiaokun; Jia, Zhuqing; Zhu, Jingxian; Dai, Linghui; Chen, Wenqing; Yin, Ling; Chen, Haifeng; Zhou, Chunyan; Ao, Yingfang

2012-04-01

Mesenchymal stem cell (MSC) is a promising cell source candidate in tissue engineering (TE) and regenerative medicine. However, the inability to target MSCs in tissues of interest with high efficiency and engraftment has become a significant barrier for MSC-based therapies. The mobilization and transfer of MSCs to defective/damaged sites in tissues or organs in vivo with high efficacy and efficiency has been a major concern. In the present study, we identified a peptide sequence (E7) with seven amino acids through phage display technology, which has a high specific affinity to bone marrow-derived MSCs. Subsequent analysis suggested that the peptide could efficiently interact specifically with MSCs without any species specificity. Thereafter, E7 was covalently conjugated onto polycaprolactone (PCL) electrospun meshes to construct an "MSC-homing device" for the recruitment of MSCs both in vitro and in vivo. The E7-conjugated PCL electrospun meshes were implanted into a cartilage defect site of rat knee joints, combined with a microfracture procedure to mobilize the endogenous MSCs. After 7 d of implantation, immunofluorescence staining showed that the cells grown into the E7-conjugated PCL electrospun meshes yielded a high positive rate for specific MSC surface markers (CD44, CD90, and CD105) compared with those in arginine-glycine-aspartic acid (RGD)-conjugated PCL electrospun meshes (63.67% vs. 3.03%; 59.37% vs. 2.98%; and 61.45% vs. 3.82%, respectively). Furthermore, the percentage of CD68 positive cells in the E7-conjugated PCL electrospun meshes was much lower than that in the RGD-conjugated PCL electrospun meshes (5.57% vs. 53.43%). This result indicates that E7-conjugated PCL electrospun meshes absorb much less inflammatory cells in vivo than RGD-conjugated PCL electrospun meshes. The results of the present study suggest that the identified E7 peptide sequence has a high specific affinity to MSCs. Covalently conjugating this peptide on the synthetic PCL mesh significantly enhanced the MSC recruitment of PCL in vivo. This method provides a wide range of potential applications in TE. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced retained dose uniformity in NiTi spinal correction rod treated by three-dimensional mesh-assisted nitrogen plasma immersion ion implantation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Q. Y.; Hu, T.; Kwok, Dixon T. K.

2010-05-15

Owing to the nonconformal plasma sheath in plasma immersion ion implantation of a rod sample, the retained dose can vary significantly. The authors propose to improve the implant uniformity by introducing a metal mesh. The depth profiles obtained with and without the mesh are compared and the implantation temperature at various locations is evaluated indirectly by differential scanning calorimeter. Our results reveal that by using the metal mesh, the retained dose uniformity along the length is greatly improved and the effects of the implantation temperature on the localized mechanical properties of the implanted NiTi shape memory alloy rod are nearlymore » negligible.« less

Evolution of the mandibular mesh implant.

PubMed

Salyer, K E; Johns, D F; Holmes, R E; Layton, J G

1977-07-01

Between 1960 and 1972, the Dallas Veterans Administration Hospital Maxillofacial Research Laboratory developed and made over 150 cast-mesh implants. Successive designs were ovoid, circular, and double-lumened in cross section to improve implant strength, surface area for bioattachment, and adjustability. Sleeves, collars, and bows were employed in the assembly of these implants, with an acrylic condylar head attached when indicated. In 1972, our laboratory developed a mandibular mesh tray, cast in one piece on a single sprue, with preservation of the vertically adjustable ramus. Stainless steel replaced Vitallium because of its greater malleability. Essentially, a lost-wax technique is used to cast the mesh tray. The model of a mandibular segment is duplicated as a refractory model. Mesh wax, made in our own custom-made die, is adapted to the refractory model. The unit is then sprued and invested. The wax is fired our of the mold in a gas furnace. Casting is done by the transferral of molten stainless steel from the crucible to the mold by centrifugal force in an electro-induction casting machine. Other mesh implants that have been developed are made from wire mesh, Dacron mesh, cast Ticonium, and hydroformed titanium.

DETERIORATION IN BIOMECHANICAL PROPERTIES OF THE VAGINA FOLLOWING IMPLANTATION OF A HIGH STIFFNESS PROLAPSE MESH

PubMed Central

Feola, Andrew; Abramowitch, Steven; Jallah, Zegbeh; Stein, Suzan; Barone, William; Palcsey, Stacy; Moalli, Pamela

2012-01-01

Objective Define the impact of prolapse mesh on the biomechanical properties of the vagina by comparing the prototype Gynemesh PS (Ethicon, Somerville, NJ) to 2 new generation lower stiffness meshes, SmartMesh (Coloplast, Minneapolis, MN) and UltraPro (Ethicon). Design A study employing a non-human primate model Setting University of Pittsburgh Population 45 parous rhesus macaques Methods Meshes were implanted via sacrocolpexy after hysterectomy and compared to Sham. Because its stiffness is highly directional UltraPro was implanted in two directions: UltraPro Perpendicular (less stiff) and UltraPro Parallel (more stiff), with the indicated direction referring to the blue orientation lines. The mesh-vaginal complex (MVC) was excised en toto after 3 months. Main Outcome Measures Active mechanical properties were quantified as contractile force generated in the presence of 120 mM KCl. Passive mechanical properties (a tissues ability to resist an applied force) were measured using a multi-axial protocol. Results Vaginal contractility decreased 80% following implantation with the Gynemesh PS (p=0.001), 48% after SmartMesh (p=0.001), 68% after UltraPro parallel (p=0.001) and was highly variable after UltraPro perpendicular (p =0.16). The tissue contribution to the passive mechanical behavior of the MVC was drastically reduced for Gynemesh PS (p=0.003) but not SmartMesh (p=0.9) or UltraPro independent of the direction of implantation (p=0.68 and p=0.66, respectively). Conclusions Deterioration of the mechanical properties of the vagina was highest following implantation with the stiffest mesh, Gynemesh PS. Such a decrease associated with implantation of a device of increased stiffness is consistent with findings from other systems employing prostheses for support. PMID:23240801

Deterioration in biomechanical properties of the vagina following implantation of a high-stiffness prolapse mesh.

PubMed

Feola, A; Abramowitch, S; Jallah, Z; Stein, S; Barone, W; Palcsey, S; Moalli, P

2013-01-01

To define the impact of prolapse mesh on the biomechanical properties of the vagina by comparing the prototype Gynemesh PS (Ethicon) to two new-generation lower stiffness meshes, SmartMesh (Coloplast) and UltraPro (Ethicon). A study employing a nonhuman primate model. University of Pittsburgh, PA, USA. Forty-five parous rhesus macaques. Meshes were implanted via sacrocolpopexy after hysterectomy and compared with sham. Because its stiffness is highly directional, UltraPro was implanted in two directions: UltraPro Perpendicular (less stiff) and UltraPro Parallel (more stiff), with the indicated direction referring to the position of the blue orientation lines relative to the longitudinal axis of the vagina. The mesh-vaginal complex (MVC) was excised in toto after 3 months. Active mechanical properties were quantified as the contractile force generated in the presence of 120 mmol/l KCl. Passive mechanical properties (a tissue's ability to resist an applied force) were measured using a multiaxial protocol. Vaginal contractility decreased by 80% following implantation with the Gynemesh PS (P = 0.001), 48% after SmartMesh (P = 0.001), 68% after UltraPro Parallel (P = 0.001) and was highly variable after UltraPro Perpendicular (P = 0.16). The tissue contribution to the passive mechanical behaviour of the MVC was drastically reduced for Gynemesh PS (P = 0.003), but not for SmartMesh (P = 0.9) or UltraPro independent of the direction of implantation (P = 0.68 and P = 0.66, respectively). Deterioration of the mechanical properties of the vagina was highest following implantation with the stiffest mesh, Gynemesh PS. Such a decrease associated with implantation of a device of increased stiffness is consistent with findings from other systems employing prostheses for support. © 2013 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2013 RCOG.

Biomimetic oral mucin from polymer micelle networks

NASA Astrophysics Data System (ADS)

Authimoolam, Sundar Prasanth

Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated using affinity-based interactions on synthetic and biological surfaces. Unlike conventional polyelectrolyte-based LBL methods, pre-assembled biotin-functionalized filamentous (worm-like) micelles was utilized as the network building block, which from complementary additions of streptavidin generated synthetic networks of desired thickness. The biomimetic nature in those synthetic networks are studied by evaluating its structural and bio-functional properties. Structurally, synthetic networks formed a nanoporous mesh. The networks demonstrated excellent surface hydration property and were able capable of microbial capture. Those functional properties are akin to that of natural mucin networks. Further, the role of synthetic mucin as a drug delivery vehicle, capable of providing localized and tunable release was demonstrated. By incorporating antibacterial curcumin drug loading within synthetic networks, bacterial growth inhibition was also demonstrated. Thus, such bioactive interfaces can serve as a model for independently characterizing mucin network properties and through its role as a drug carrier vehicle it presents exciting future opportunities for localized drug delivery, in regenerative applications and as bio-functional implant coats. KEYWORDS: Biomimic, Bioapplication, Drug delivery, Filomicelle, Mucin, Polymer networks.

Synthetic vaginal mesh for pelvic organ prolapse.

PubMed

Iglesia, Cheryl B

2011-10-01

The purpose of this review is to summarize recently published comparative trials on synthetic vaginal mesh versus traditional native tissue repairs for pelvic organ prolapse. Although studies suggest benefit from the use of synthetic vaginal mesh for anterior compartment prolapse, data are limited on the use of mesh for posterior and apical prolapse when compared with native tissue repair. The benefits of a more durable repair must be weighed against risks such as the development of de-novo stress incontinence, visceral injury, dyspareunia, pelvic pain and mesh contraction, exposure and extrusion requiring reoperation. Furthermore, the success rates of native tissue repairs are higher than previously considered using updated validated composite outcomes that incorporate both subjective relief of bulge and objective cure defined as prolapse above the hymenal ring. Surgeons placing synthetic mesh for pelvic organ prolapse should counsel patients regarding the potential benefits, risks, and alternatives including native tissue repairs. Level 1 evidence suggests anterior synthetic mesh may be superior to anterior repair. Expert opinion suggests potential benefit of vaginal mesh for recurrences, hysteropexy, and advanced prolapse in patients with medical co-morbidities precluding invasive open and endoscopic sacrocolpopexies; however, comparative clinical trials with long-term data are needed. (C) 2011 Lippincott Williams & Wilkins, Inc.

Cyclodextrin modified PLLA parietal reinforcement implant with prolonged antibacterial activity.

PubMed

Vermet, G; Degoutin, S; Chai, F; Maton, M; Flores, C; Neut, C; Danjou, P E; Martel, B; Blanchemain, N

2017-04-15

The use of textile meshes in hernia repair is widespread in visceral surgery. Though, mesh infection is a complication that may prolong the patient recovery period and consequently presents an impact on public health economy. Such concern can be avoided thanks to a local and extended antibiotic release on the operative site. In recent developments, poly-l-lactic acid (PLLA) has been used in complement of polyethyleneterephthalate (Dacron®) (PET) or polypropylene (PP) yarns in the manufacture of semi-resorbable parietal implants. The goal of the present study consisted in assigning drug reservoir properties and prolonged antibacterial effect to a 100% PLLA knit through its functionalization with a cyclodextrin polymer (polyCD) and activation with ciprofloxacin. The study focused i) on the control of degree of polyCD functionalization of the PLLA support and on its physical and biological characterization by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and cell viability, ii) on the understanding of drug/meshes interaction using mathematic model and iii) on the correlation between drug release studies in phosphate buffer saline (PBS) and microbiological evaluation of meshes and release medium against E. coli and S. aureus. All above mentioned tests highlighted the contribution of polyCD on the improved performances of the resulting antibacterial implantable material. 1. We managed for the first time, with well-defined parameters in terms of temperature and time of treatment, to functionalize a bio-absorbable synthetic material to improve drug sorption and drug release properties without affecting its mechanical properties. 2. We analyzed for the first time the degradation of our coating products by mass spectroscopy to show that only citrate and cyclodextrin residues (and glucose units) without any cytotoxicity are formed. 3. We managed to improve the mechanical properties of the PLA with the cyclodextrin polymer to form a composite. The assembly (cyclodextrin polymer and PLLA) remains biodegradable. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Development of better tolerated prosthetic materials: applications in gynecological surgery].

PubMed

Debodinance, P; Delporte, P; Engrand, J B; Boulogne, M

2002-10-01

Meshes have come to be widely used for surgical repair of the dysfunctional pelvic floor. The problem to date has been mesh intolerance. History. The first meshes were made with silver filigrees or stainless steel. Non-metallic and non-absorbable synthetic prostheses include nylon, silastic, polytetrafluoroethylene as well as expansive polyester and polypropylene forms. Most of the absorbable prostheses are made of polyglycolic acid and polyglactine 910. Classification. Four groups of biomaterials can be described according to pore size. Mechanical and biological properties. The mechanical properties of meshes have been tested industrially for resistance, pliability, elasticity and ductile qualities. These properties depend on type of tissue structure (woven or knitted) and the type of fiber used (mono and multi-filaments). The goal is to obtain a "silent" material, i.e. a material which does not trigger a host tissue reaction. Introducing the foreign body induces a "scarring" response. This fibroblastic reaction replaces the inflammatory reaction, leading to progressive colonization of the prosthesis. The major risk is infection caused by a disturbance of the inflammatory phase and bacterial development. Bacteria can be trapped in fibrotic tissue, with the risk of delayed infection. Immunological reactions may have an additive effect. These problems are not encountered with absorbable meshes. An ideal implant material must: not undergo physical modification by tissue fluids, be chemically inert, not trigger inflammatory or foreign body cell response in body tissues, be noncarcinogenic and nonallergenic, be capable of resisting mechanical stress and sterilization, and be able to be manufactured in the necessary shape. Polyester, polypropylene and expansive polytetrafluoroethylene fulfill these criteria. The ideal mesh. Eleven criteria are proposed. Complications for hernia repair. Infection and seroma are the most frequent complications with micro-porous meshes. Macro-porous meshes can cause erosive phenomena and adhesions. Retraction of synthetic tissues is observed in 20 to 30% of cases. Meshes in gynecology. In gynecology surgery, meshes made their first appearance in trans-abdominal sacrocolpopexy and slings. A detailed review of complications found in 32 articles studying slings and 22 studying sacrocolpopexy with approximately 10 types of meshes shows that intolerance of slings has oscillated between 1% with Prolene and 31% with Gore-Tex; for abdominal sacrocolpopexy the rate was between 1.7% with Prolene and 20% with Teflon. Rejection phenomena appear during the first year and are proportional to the surface area of the synthetic tissue and the proximity of the vaginal scar. New materials have been proposed over the last ten years for prolapse surgery, notably for cystocele, which accounts for 70% of all repair procedures. Nearly fifteen studies have reported a level of intolerance reaching 6%, the large majority of the meshes used being Prolene meshes. Our personal experience with 87 repair procedures has led us to the conclusion that Prolene is the most adapted mesh, allowing free tension between the bladder and the anterior vaginal wall. Continuous evaluation is needed to study these replacement materials which should in theory, improve the rate of recurrence, which is at present 20% with classic procedures not using a mesh.

A preclinical evaluation of polypropylene/polylacticacid hybrid meshes for fascial defect repair using a rat abdominal hernia model

PubMed Central

Le Teuff, Isabelle; Huberlant, Stephanie; Carteron, Patrick; Letouzey, Vincent; de Tayrac, Renaud

2017-01-01

Objectives Synthetic mesh surgery for both abdominal and urogenital hernia repair is often unsatisfactory in the long-term due to postoperative complications. We hypothesized that a semi-degradable mesh hybrid may provide more appropriate biocompatibility with comparable mechanical properties. The aim was to compare its in vivo biocompatibility with a commercial polypropylene (PP) mesh. Methods 72 rats were randomly allocated to either our new composite mesh (monofilament PP mesh knitted with polylactic-acid-fibers (PLA)) or to a commercially available PP mesh that was used as a control. 15, 90, and 180 days after implantation into the rat abdomen mesh tissue complexes were analysed for erosion, contraction, foreign body reaction, tissue integration and biomechanical properties. Results No differences were seen in regard to clinical parameters including erosion, contraction or infection rates between the two groups. Biomechanical properties including breaking load, stiffness and deformation did not show any significant differences between the different materials at any timepoint. Macrophage staining did not reveal any significant differences between the two groups or between timepoints either. In regard to collagen I there was significantly less collagen I in the PP group compared to the PP/ PLA group at day 180. Collagen III did not show any significant differences at any timepoint between the two groups. Conclusion A PP/PLA hybrid mesh, leaving a low amount of PP after PLA degradation seems to have comparable biomechanical properties like PP at 180 days due to enhanced collagen production without significant differences in erosion, contraction, herniation or infection rates. PMID:28598983

[Expandable metal mesh stents for treatment of tracheal stenoses and tracheomalacia].

PubMed

Müller, C; Dienemann, H; Hoffmann, H; Berger, H; Storck, M; Jolk, A; Schildberg, F W

1993-01-01

The treatment of tracheo-bronchial stenosis or tracheomalacia is mainly carried out by means of resection or tracheoplastic operative strategies. Since the introduction of metal-mesh stents, a definitive endoluminal therapy has to be considered under new aspects. Six patients with malignant stenosis or tracheomalacia due to compression were treated by implantation of Palmaz- or Wallstents. Immediately after the implantation, patients were relieved from dyspnoea, the forced inspiratory volume-1 (FIV1) was normalized. All implanted stents were well tolerated, even in the long-time follow-up (19 months). Bronchoscopic control showed overgrowth of the metal meshes by respiratory epithelium. The implantation of metal-mesh stents is an adequate alternative in the treatment of malignant stenosis and tracheomalacia.

Financial implications of ventral hernia repair: a hospital cost analysis.

PubMed

Reynolds, Drew; Davenport, Daniel L; Korosec, Ryan L; Roth, J Scott

2013-01-01

Complicated ventral hernias are often referred to tertiary care centers. Hospital costs associated with these repairs include direct costs (mesh materials, supplies, and nonsurgeon labor costs) and indirect costs (facility fees, equipment depreciation, and unallocated labor). Operative supplies represent a significant component of direct costs, especially in an era of proprietary synthetic meshes and biologic grafts. We aim to evaluate the cost-effectiveness of complex abdominal wall hernia repair at a tertiary care referral facility. Cost data on all consecutive open ventral hernia repairs (CPT codes 49560, 49561, 49565, and 49566) performed between 1 July 2008 and 31 May 2011 were analyzed. Cases were analyzed based upon hospital status (inpatient vs. outpatient) and whether the hernia repair was a primary or secondary procedure. We examined median net revenue, direct costs, contribution margin, indirect costs, and net profit/loss. Among primary hernia repairs, cost data were further analyzed based upon mesh utilization (no mesh, synthetic, or biologic). Four-hundred and fifteen patients underwent ventral hernia repair (353 inpatients and 62 outpatients); 173 inpatients underwent ventral hernia repair as the primary procedure; 180 inpatients underwent hernia repair as a secondary procedure. Median net revenue ($17,310 vs. 10,360, p < 0.001) and net losses (3,430 vs. 1,700, p < 0.025) were significantly greater for those who underwent hernia repair as a secondary procedure. Among inpatients undergoing ventral hernia repair as the primary procedure, 46 were repaired without mesh; 79 were repaired with synthetic mesh and 48 with biologic mesh. Median direct costs for cases performed without mesh were $5,432; median direct costs for those using synthetic and biologic mesh were $7,590 and 16,970, respectively (p < .01). Median net losses for repairs without mesh were $500. Median net profit of $60 was observed for synthetic mesh-based repairs. The median contribution margin for cases utilizing biologic mesh was -$4,560, and the median net financial loss was $8,370. Outpatient ventral hernia repairs, with and without synthetic mesh, resulted in median net losses of $1,560 and 230, respectively. Ventral hernia repair is associated with overall financial losses. Inpatient synthetic mesh repairs are essentially budget neutral. Outpatient and inpatient repairs without mesh result in net financial losses. Inpatient biologic mesh repairs result in a negative contribution margin and striking net financial losses. Cost-effective strategies for managing ventral hernias in a tertiary care environment need to be developed in light of the financial implications of this patient population.

[The ultrasound semiotics of uncomplicated wound healing after inguinal mesh plastics].

PubMed

Kharitonov, S V; Ziniakova, M V

2012-01-01

Dynamic ultrasound (US) investigation was performed in 89 patients operated on inguinal hernia with the use of meshes of various type. The US scanning proved to be a highly informative means of visualization, allowing the objective postoperative assessment of muscular and aponeurotic structures as well as the implant form and position. The study showed, that the mesh implantation was always accompanied by the exudative tissue reaction, which was determined by the physico-chemical characteristics of the implant.

Biomechanical and histologic evaluation of two application forms of surgical glue for mesh fixation to the abdominal wall.

PubMed

Ortillés, Á; Pascual, G; Peña, E; Rodríguez, M; Pérez-Köhler, B; Mesa-Ciller, C; Calvo, B; Bellón, J M

2017-11-01

The use of an adhesive for mesh fixation in hernia repair reduces chronic pain and minimizes tissue damage in the patient. This study was designed to assess the adhesive properties of a medium-chain (n-butyl) cyanoacrylate glue applied as drops or as a spray in a biomechanical and histologic study. Both forms of glue application were compared to the use of simple-loose or continuous-running polypropylene sutures for mesh fixation. Eighteen adult New Zealand White rabbits were used. For mechanical tests in an ex vivo and in vivo study, patches of polypropylene mesh were fixed to an excised fragment of healthy abdominal tissue or used to repair a partial abdominal wall defect in the rabbit respectively. Depending on the fixation method used, four groups of 12 implants each or 10 implants each respectively for the ex vivo and in vivo studies were established: Glue-Drops, Glue-Spray, Suture-Simple and Suture-Continuous. Biomechanical resistance in the ex vivo implants was tested five minutes after mesh fixation. In vivo implants for biomechanical and histologic assessment were collected at 14 days postimplant. In the ex vivo study, the continuous suture implants showed the highest failure sample tension, while the implants fixed with glue showed lower failure sample tension values. However, the simple and continuous suture implants returned the highest stretch values. In the in vivo implants, failure sample tension values were similar among groups while the implants fixed with a continuous running suture had the higher stretch values, and the glue-fixed implants the lower stretch values. All meshes showed good tissue integration within the host tissue regardless of the fixation method used. Our histologic study revealed the generation of a denser, more mature repair tissue when the cyanoacrylate glue was applied as a spray rather than as drops. Copyright © 2017 Elsevier Ltd. All rights reserved.

Does expanded polytetrafluoroethylene mesh really shrink after laparoscopic ventral hernia repair?

PubMed

Carter, P R; LeBlanc, K A; Hausmann, M G; Whitaker, J M; Rhynes, V K; Kleinpeter, K P; Allain, B W

2012-06-01

The shrinkage of mesh has been cited as a possible explanation for hernia recurrence. Expanded polytetrafluoroethylene (ePTFE) is unique in that it can be visualized on computed tomography (CT). Some animal studies have shown a greater than 40% rate of contraction of ePTFE; however, very few human studies have been performed. A total of 815 laparoscopic incisional/ventral hernia (LIVH) repairs were performed by a single surgical group. DualMesh Plus (ePTFE) (WL Gore & Associates, Newark, DE) was placed in the majority of these patients using both transfascial sutures and tack fixation. Fifty-eight patients had postoperative CTs of the abdomen and pelvis with ePTFE and known transverse diameter of the implanted mesh. The prosthesis was measured on the CT using the AquariusNet software program (TeraRecon, San Mateo, CA), which outlines the mesh and calculates the total length. Data were collected regarding the original mesh size, known linear dimension of mesh, seroma formation, and time interval since mesh implantation in months. The mean shrinkage rate was 6.7%. The duration of implantation ranged from 6 weeks to 78 months, with a median of 15 months. Seroma was seen in 8.6% (5) of patients. No relationship was identified between the percentage of shrinkage and the original mesh size (P = 0.78), duration of time implanted (P = 0.57), or seroma formation (P = 0.074). In 27.5% (16) of patients, no shrinkage of mesh was identified. Of the patients who did experience mesh shrinkage, the range of shrinkage was 2.6-25%. Our results are markedly different from animal studies and show that ePTFE has minimal shrinkage after LIVH repair. The use of transfascial sutures in addition to tack fixation may have an implication on the mesh contraction rates.

Is vaginal mesh a stimulus of autoimmune disease?

PubMed

Chughtai, Bilal; Sedrakyan, Art; Mao, Jialin; Eilber, Karyn S; Anger, Jennifer T; Clemens, J Quentin

2017-05-01

Polypropylene mesh has been used as a means of reinforcing weak tissues in women with pelvic organ prolapse and stress urinary incontinence. We sought to investigate a potential link between the development of systemic/autoimmune disorders and synthetic polypropylene mesh repairs. New York State Department of Health Statewide Planning and Research Cooperative System data were utilized to conduct this retrospective cohort study. Adult women undergoing surgery for pelvic organ prolapse with vaginally implanted mesh from January 2008 through December 2009 in inpatient and ambulatory surgery settings in New York State were identified. Two separate control cohorts were created to compare outcomes, including a screening colonoscopy cohort and a vaginal hysterectomy cohort for benign gynecologic conditions (without pelvic organ prolapse repair or sling). Patients in the mesh cohort were individually matched to the control cohorts based on demographics, comorbidities, and procedure date. The development of systemic/autoimmune disease was determined before and after matching for 1-year, 2-year, 3-year, and entire follow-up (up to 6 years until December 2014) and differences between groups were evaluated. A total of 2102 patients underwent mesh-based pelvic organ prolapse surgery from January 2008 through December 2009. In the control cohorts, 37,298 patients underwent colonoscopy and 7338 underwent vaginal hysterectomy. When patients were matched based on demographics, comorbidities, and procedure time, mesh-based surgery was not associated with an increased risk of developing autoimmune disease at any of the evaluated time periods. Mesh-based vaginal surgery was not associated with the development of systemic/autoimmune diseases. These data refute claims against mesh as a cause of systemic disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Three-dimensional analysis of implanted magnetic-resonance-visible meshes.

PubMed

Sindhwani, Nikhil; Feola, Andrew; De Keyzer, Frederik; Claus, Filip; Callewaert, Geertje; Urbankova, Iva; Ourselin, Sebastien; D'hooge, Jan; Deprest, Jan

2015-10-01

Our primary objective was to develop relevant algorithms for quantification of mesh position and 3D shape in magnetic resonance (MR) images. In this proof-of-principle study, one patient with severe anterior vaginal wall prolapse was implanted with an MR-visible mesh. High-resolution MR images of the pelvis were acquired 6 weeks and 8 months postsurgery. 3D models were created using semiautomatic segmentation techniques. Conformational changes were recorded quantitatively using part-comparison analysis. An ellipticity measure is proposed to record longitudinal conformational changes in the mesh arms. The surface that is the effective reinforcement provided by the mesh is calculated using a novel methodology. The area of this surface is the effective support area (ESA). MR-visible mesh was clearly outlined in the images, which allowed us to longitudinally quantify mesh configuration between 6 weeks and 8 months after implantation. No significant changes were found in mesh position, effective support area, conformation of the mesh's main body, and arm length during the period of observation. Ellipticity profiles show longitudinal conformational changes in posterior arms. This paper proposes novel methodologies for a systematic 3D assessment of the position and morphology of MR-visible meshes. A novel semiautomatic tool was developed to calculate the effective area of support provided by the mesh, a potentially clinically important parameter.

Alloplastic adjuncts in breast reconstruction

PubMed Central

Cabalag, Miguel S.; Rostek, Marie; Miller, George S.; Chae, Michael P.; Quinn, Tam; Rozen, Warren M.

2016-01-01

Background There has been an increasing role of acellular dermal matrices (ADMs) and synthetic meshes in both single- and two-stage implant/expander breast reconstruction. Numerous alloplastic adjuncts exist, and these vary in material type, processing, storage, surgical preparation, level of sterility, available sizes and cost. However, there is little published data on most, posing a significant challenge to the reconstructive surgeon trying to compare and select the most suitable product. The aims of this systematic review were to identify, summarize and evaluate the outcomes of studies describing the use of alloplastic adjuncts for post-mastectomy breast reconstruction. The secondary aims were to determine their cost-effectiveness and analyze outcomes in patients who also underwent radiotherapy. Methods Using the PRSIMA 2009 statement, a systematic review was conducted to find articles reporting on the outcomes on the use of alloplastic adjuncts in post-mastectomy breast reconstruction. Multiple databases were searched independently by three authors (Cabalag MS, Miller GS and Chae MP), including: Ovid MEDLINE (1950 to present), Embase (1980 to 2015), PubMed and Cochrane Database of Systematic Reviews. Results Current published literature on available alloplastic adjuncts are predominantly centered on ADMs, both allogeneic and xenogeneic, with few outcome studies available for synthetic meshes. Outcomes on the 89 articles, which met the inclusion criteria, were summarized and analyzed. The reported outcomes on alloplastic adjunct-assisted breast reconstruction were varied, with most data available on the use of ADMs, particularly AlloDerm® (LifeCell, Branchburg, New Jersey, USA). The use of ADMs in single-stage direct-to-implant breast reconstruction resulted in lower complication rates (infection, seroma, implant loss and late revision), and was more cost effective when compared to non-ADM, two-stage reconstruction. The majority of studies demonstrated inferior outcomes in ADM assisted, two-stage expander-to-implant reconstruction compared to non-ADM use. Multiple studies suggest that the use of ADMs results in a reduction of capsular contracture rates. Additionally, the reported beneficial effects of ADM use in irradiated tissue were varied. Conclusions ADM assisted two-stage breast reconstruction was associated with inferior outcomes when compared to non-ADM use. However, alloplastic adjuncts may have a role in single stage, direct-to-implant breast reconstruction. Published evidence comparing the long-term outcomes between the different types of adjuncts is lacking, and further level one studies are required to identify the ideal product. PMID:27047784

Simplified Technique for Incorporating a Metal Mesh into Record Bases for Mandibular Implant Overdentures.

PubMed

Godoy, Antonio; Siegel, Sharon C

2015-12-01

Mandibular implant-retained overdentures have become the standard of care for patients with mandibular complete edentulism. As part of the treatment, the mandibular implant-retained overdenture may require a metal mesh framework to be incorporated to strengthen the denture and avoid fracture of the prosthesis. Integrating the metal mesh framework as part of the acrylic record base and wax occlusion rim before the jaw relation procedure will avoid the distortion of the record base and will minimize the chances of processing errors. A simplified method to incorporate the mesh into the record base and occlusion rim is presented in this technique article. © 2015 by the American College of Prosthodontists.

Pelvic Organ Prolapse---Vaginal and Laparoscopic Mesh: The Evidence.

PubMed

Richter, Lee A; Sokol, Andrew I

2016-03-01

This report summarizes the current literature on abdominal, laparoscopic, and transvaginal mesh for the treatment of pelvic organ prolapse. This article reviews objective and subjective cure rates as well as complications associated with synthetic mesh use for pelvic organ prolapse repair. The focus is on the latest literature that provides evidence for when synthetic mesh use is most appropriate. The use of mesh for the repair of urinary incontinence is not reviewed in this article. Copyright © 2016 Elsevier Inc. All rights reserved.

In vivo characterisation of the inflammatory reaction following mesh implantation in transgenic mice models.

PubMed

Fet, N; Alizai, P H; Fragoulis, A; Wruck, C; Pufe, T; Tolba, R H; Neumann, U P; Klinge, U

2014-06-01

Hernia repair with prosthetic meshes represents one of the most common surgical procedures in the field of surgery. This intervention is always associated with an ensuing inflammatory response, angiogenesis and fibrotic encapsulation forming a foreign body granuloma (FBG) around the mesh fibres. Several studies have described this inflammatory reaction by characterising inflammatory cell infiltrate around the FBG after mesh explantation. However, very little is known about the real-time progression of such an inflammatory response. The aim of this study was to investigate the feasibility of monitoring the ongoing inflammatory response to mesh implantation using bioluminescence in vivo. Three luciferase transgenic mice strains (FVB/N-Tg(Vegfr2-luc)-Xen, BALB/C-Tg(NFκB-RE-luc)-Xen and Tg(INS/EpRE-Luc)T20Rbl) were used. Mice were anaesthetized with 2 % isoflurane, and two incisions were made on the left and right sides of the abdomen of the mice. A 1-cm(2) propylene mesh was implanted subcutaneously in the right incision wound of each mouse, and the left wound served as control. Two hundred microliters of D-luciferin was injected into the mice, and bioluminescence measurements were done prior to the surgical intervention and subsequently every 3 days. After mesh explantation, histological analysis was done. Statistical analysis was done using prism GraphPad software. Bioluminescence results revealed different time points of maximum signal for the different mice strains. VEGFR2 gene expression peaked on day 6, NFkB on day 12 and ARE on day 3 post mesh implantation. We also observed much higher bioluminescent signal around the FBG surrounding the mesh as compared to the control wound, with p < 0.05 for all the different mice strains. Our results prove the possibility of monitoring the inflammatory reaction after mesh implantation in vivo using bioluminescence signal release. This provides a novel method of accessing and accurately describing the ongoing inflammatory response over a given period of time.

Varying Degrees of Nonlinear Mechanical Behavior Arising From Geometric Differences of Urogynecological Meshes

PubMed Central

Feola, Andrew; Pal, Siladitya; Moalli, Pamela; Maiti, Spandan; Abramowitch, Steven

2014-01-01

Synthetic polypropylene meshes were designed to restore pelvic organ support for women suffering from pelvic organ prolapse; however, the FDA released two notifications regarding the potential complications associated with mesh implantation. Our aim was to characterize the structural properties of Restorelle and UltraPro subjected to uniaxial tension along perpendicular directions, and then model the tensile behavior of these meshes utilizing a co-rotational finite element model, with an imbedded linear or fiber-recruitment local stress-strain relationship. Both meshes exhibited highly nonlinear stress-strain behavior; Restorelle had no significant differences between the two perpendicular directions, while UltraPro had a 93% difference in the low (initial) stiffness (p=0.009) between loading directions. Our model predicted that early alignment of the mesh segments in the loading direction and subsequent stretching could explain the observed nonlinear tensile behavior. However, a nonlinear stress-strain response in the stretching regime, that may be inherent to the mesh segment, was required to better capture experimental results. Utilizing a nonlinear fiber recruitment model with two parameters A and B, we observed improved agreement between the simulations and the experimental results. An inverse analysis found A=120 MPa and B=1.75 for Restorelle (RMSE=0.36). This approach yielded A=30 MPa and B=3.5 for UltraPro along one direction (RMSE=0.652), while the perpendicular orientation resulted in A=130 MPa and B=4.75 (RMSE=4.36). From the uniaxial protocol, Restorelle was found to have little variance in structural properties along these two perpendicular directions; however, UltraPro was found to behave anisotropically. PMID:25011619

Application of confocal laser microscopy for monitoring mesh implants in herniology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zakharov, V P; Belokonev, V I; Bratchenko, I A

2011-04-30

The state of the surface of mesh implants and their encapsulation region in herniology is investigated by laser confocal microscopy. A correlation between the probability of developing relapses and the size and density of implant microdefects is experimentally shown. The applicability limits of differential reverse scattering for monitoring the post-operation state of implant and adjacent tissues are established based on model numerical experiments. (optical technologies in biophysics and medicine)

The long-term behavior of lightweight and heavyweight meshes used to repair abdominal wall defects is determined by the host tissue repair process provoked by the mesh.

PubMed

Pascual, Gemma; Hernández-Gascón, Belén; Rodríguez, Marta; Sotomayor, Sandra; Peña, Estefania; Calvo, Begoña; Bellón, Juan M

2012-11-01

Although heavyweight (HW) or lightweight (LW) polypropylene (PP) meshes are widely used for hernia repair, other alternatives have recently appeared. They have the same large-pore structure yet are composed of polytetrafluoroethylene (PTFE). This study compares the long-term (3 and 6 months) behavior of meshes of different pore size (HW compared with LW) and composition (PP compared with PTFE). Partial defects were created in the lateral wall of the abdomen in New Zealand White rabbits and then repaired by the use of a HW or LW PP mesh or a new monofilament, large-pore PTFE mesh (Infinit). At 90 and 180 days after implantation, tissue incorporation, gene and protein expression of neocollagens (reverse transcription-polymerase chain reaction/immunofluorescence), macrophage response (immunohistochemistry), and biomechanical strength were determined. Shrinkage was measured at 90 days. All three meshes induced good host tissue ingrowth, yet the macrophage response was significantly greater in the PTFE implants (P < .05). Collagen 1/3 mRNA levels failed to vary at 90 days yet in the longer term, the LW meshes showed the reduced genetic expression of both collagens (P < .05) accompanied by increased neocollagen deposition, indicating more efficient mRNA translation. After 90-180 days of implant, tensile strengths and elastic modulus values were similar for all 3 implants (P > .05). Host collagen deposition is mesh pore size dependent whereas the macrophage response induced is composition dependent with a greater response shown by PTFE. In the long term, macroporous meshes show comparable biomechanical behavior regardless of their pore size or composition. Copyright © 2012 Mosby, Inc. All rights reserved.

Tissue reaction to a titanium-nickelide mesh implant after plasty of postresection defects of anatomic structures of the chest.

PubMed

Topolnitskiy, E B; Dambaev, G Ts; Hodorenko, V N; Fomina, T I; Shefer, N A; Gunther, V E

2012-07-01

We studied morphological features of the regenerate formed after postresection defect plasty of the pericardium, diaphragm, and thorax with a mesh implant made of nanostructural titanium-nickelide threads. The newly formed tissue grew through the implant with the formation of an integrated tissue regenerate ensuring anatomic and physiological restoration of this area.

High-fidelity meshes from tissue samples for diffusion MRI simulations.

PubMed

Panagiotaki, Eleftheria; Hall, Matt G; Zhang, Hui; Siow, Bernard; Lythgoe, Mark F; Alexander, Daniel C

2010-01-01

This paper presents a method for constructing detailed geometric models of tissue microstructure for synthesizing realistic diffusion MRI data. We construct three-dimensional mesh models from confocal microscopy image stacks using the marching cubes algorithm. Random-walk simulations within the resulting meshes provide synthetic diffusion MRI measurements. Experiments optimise simulation parameters and complexity of the meshes to achieve accuracy and reproducibility while minimizing computation time. Finally we assess the quality of the synthesized data from the mesh models by comparison with scanner data as well as synthetic data from simple geometric models and simplified meshes that vary only in two dimensions. The results support the extra complexity of the three-dimensional mesh compared to simpler models although sensitivity to the mesh resolution is quite robust.

Bone Marrow–Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection

PubMed Central

Criman, Erik T.; Kurata, Wendy E.; Matsumoto, Karen W.; Aubin, Harry T.; Campbell, Carmen E.

2016-01-01

Background: The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli). Methods: Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 105 colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses. Results: MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation. Conclusions: Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity. PMID:27482490

[Indications of mesh in surgical treatment of pelvic organ prolapse by vaginal route: expert consensus from the French College of Gynecologists and Obstetricians (CNGOF)].

PubMed

Deffieux, X; Sentilhes, L; Savary, D; Letouzey, V; Marcelli, M; Mares, P; Pierre, F

2013-11-01

To determine the indications and contraindications concerning prosthetic surgery by vaginal route for pelvic organ prolapse. Literature review and rating of proposals using a formal consensus method. Before surgery for genital prolapse, the patient should be counselled about the different existing techniques (abdominal and vaginal surgery with and without mesh), the reasons why the surgeon offered her the placement of a synthetic mesh and also other nonsurgical treatments (pelvic floor rehabilitation and pessary). The intervention must be preceded by an assessment of bothersome pelvic, urinary, digestive and sexual symptoms. For the surgical treatment of cystocele, the use of a synthetic mesh placed by vaginal route is not recommended routinely. It should be discussed on a case by case considering the risk/benefit ratio. In patients presenting with cystocele recurrence, the placement of a synthetic mesh is a reasonable option, in order to reduce the risk of cystocele recurrence. With the exception of a few situations (rectocele recurrence), the placement of a synthetic mesh is not recommended as first-line therapy for the surgical treatment of rectocele by vaginal route. In case of uterine or vaginal vault prolapse, repositioning the vaginal vault or uterus using synthetic mesh arms is not recommended as first-line surgical therapy. Surgeons should implement established preventive recommendations that may reduce the risk of complications. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Direct metal laser sintering (DMLS) of a customized titanium mesh for prosthetically guided bone regeneration of atrophic maxillary arches.

PubMed

Ciocca, L; Fantini, M; De Crescenzio, F; Corinaldesi, G; Scotti, R

2011-11-01

This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD-CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD-CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

PubMed

Köckerling, F; Alam, N N; Antoniou, S A; Daniels, I R; Famiglietti, F; Fortelny, R H; Heiss, M M; Kallinowski, F; Kyle-Leinhase, I; Mayer, F; Miserez, M; Montgomery, A; Morales-Conde, S; Muysoms, F; Narang, S K; Petter-Puchner, A; Reinpold, W; Scheuerlein, H; Smietanski, M; Stechemesser, B; Strey, C; Woeste, G; Smart, N J

2018-04-01

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations. A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used. The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes. The routine use of biologic and biosynthetic meshes cannot be recommended.

Complex rectovaginal fistulas after pelvic organ prolapse repair with synthetic mesh: a multidisciplinary approach to evaluation and management.

PubMed

Choi, Judy M; Nguyen, Vian; Khavari, Rose; Reeves, Keith; Snyder, Michael; Fletcher, Sophie G

2012-01-01

The use of synthetic mesh for transvaginal pelvic organ prolapse (POP) repair is associated with the rare complication of mesh erosion into hollow viscera. This study presents a single-institution series of complex rectovaginal fistulas (RVFs) after synthetic mesh-augmented POP repair, as well as strategies for identification and management. Institutional review board approval was obtained for this retrospective study. Data were collected and analyzed on all female patients undergoing RVF repair from 2000 to 2011 at our institution. Thirty-seven patients underwent RVF repair at our multidisciplinary center for restorative pelvic medicine. Of these, 10 (27.0%) were associated with POP repairs using mesh. The POP repairs resulting in RVF were transvaginal repair with mesh (n = 8), laparoscopic sacrocolpopexy with concomitant traditional posterior repair (n = 1), and robotic-assisted laparoscopic sacrocolpopexy (n = 1). Time to presentation was an average of 7.1 months after POP repair. Patients underwent a mean of 4.4 surgeries for definitive RVF repair, with 40% of patients requiring a bowel diversion (3 temporary ileostomies and 1 long-term colostomy). Mean follow-up time after last surgery was 9.2 months. On follow-up, 1 patient has a persistent fistula with vaginal mesh extrusion. One patient has persistent pelvic pain. This series highlights the significant impact of synthetic mesh complications in the posterior compartment. These complications should be cautionary for synthetic graft use by those with limited experience, particularly when an alternate choice of traditional repair is available. When symptoms of RVF are present, collaboration with a colon and rectal specialist should be initiated as soon as possible for evaluation and definitive repair.

The osteoplastic effectiveness of the implants made of mesh titanium nickelide constructs.

PubMed

Mikhailovich Irianov, Iurii; Vladimirovna Diuriagina, Olga; Iurevna Karaseva, Tatiana; Anatolevich Karasev, Evgenii

2014-02-01

The purpose of the work was to study the features of reparative osteogenesis for filling the defect of tubular bone under implantation of mesh titanium nickelide constructs. Tibial fenestrated defect was modeled experimentally in 30 Wistar pubertal rats, followed by implant intramedullary insertion. The techniques of radiography, scanning electron microscopy and X-ray electron probe microanalysis were used. The mesh implant of titanium nickelide has been established to possess biocompatibility, osteoconductive and osteoinductive properties, the zone of osteogenesis and angiogenesis is created around it, bone cover is formed. Osteointegration of the implant occurs early, by 7 days after surgery, and by 30 days after surgery organotypical re-modelling of the regenerated bone takes place, as well as the defect is filled with lamellar bone tissue by the type of bone wound primary adhesion. By 30 days after surgery mineral content of the regenerated bone tissue approximates to the composition of intact cortex mineral phase.

Evaluation of the Antimicrobial Activity of Lysostaphin-Coated Hernia Repair Meshes▿

PubMed Central

Satishkumar, Rohan; Sankar, Sriram; Yurko, Yuliya; Lincourt, Amy; Shipp, John; Heniford, B. Todd; Vertegel, Alexey

2011-01-01

Bacterial infections by antibiotic-resistant Staphylococcus aureus strains are among the most common postoperative complications in surgical hernia repair with synthetic mesh. Surface coating of medical devices/implants using antibacterial peptides and enzymes has recently emerged as a potentially effective method for preventing infections. The objective of this study was to evaluate the in vitro antimicrobial activity of hernia repair meshes coated by the antimicrobial enzyme lysostaphin at different initial concentrations. Lysostaphin was adsorbed on pieces of polypropylene (Ultrapro) mesh with binding yields of ∼10 to 40% at different coating concentrations of between 10 and 500 μg/ml. Leaching of enzyme from the surface of all the samples was studied in 2% (wt/vol) bovine serum albumin in phosphate-buffered saline buffer at 37°C, and it was found that less than 3% of adsorbed enzyme desorbed from the surface after 24 h of incubation. Studies of antibacterial activity against a cell suspension of S. aureus were performed using turbidity assay and demonstrated that the small amount of enzyme leaching from the mesh surface contributes to the lytic activity of the lysostaphin-coated samples. Colony counting data from the broth count (model for bacteria in wound fluid) and wash count (model for colonized bacteria) for the enzyme-coated samples showed significantly decreased numbers of CFU compared to uncoated samples (P < 0.05). A pilot in vivo study showed a dose-dependent efficacy of lysostaphin-coated meshes in a rat model of S. aureus infection. The antimicrobial activity of the lysostaphin-coated meshes suggests that such enzyme-leaching surfaces could be efficient at actively resisting initial bacterial adhesion and preventing subsequent colonization of hernia repair meshes. PMID:21709102

Ventral incisional hernia (VIH) repair after liver transplantation (OLT) with a biological mesh: experience in 3 cases.

PubMed

Schaffellner, S; Sereinigg, M; Wagner, D; Jakoby, E; Kniepeiss, D; Stiegler, P; Haybäck, J; Müller, H

2016-05-01

Hernias after orthotopic liver transplant (OLT) occur in about 30 % of cases. Predisposing factors in liver cirrhotic patients of cases are ascites, low abdominal muscle mass and cachexia before and immunosuppression after OLT. Standard operative transplant-technique even in small hernias is to implant a mesh. For patients after liver transplantation a porcine non-cross linked biological patch being less immunogenic than synthetic and cross-linked meshes is chosen for ventral incisional hernia repair. 3 patients (1 female, 2 male), OLT indications Hepatitis C, exogenous- toxic cirrhosis, median-age 53 (51 - 56) and median time to hernia occurrence after OLT were 10 month (6 - 18 m) are documented. 2 patients suffered from diabetes, 2 from chronic-obstructive lung disease. Maintenance immunosuppressions were Everolimus in 1 patient, Everolimus + MMF in the second and Everolimus +Tacrolimus in the third patient. The biological was chosen for hernia repair due to the preexisting risk- factors. Meshes, 10 × 16 cm were placed, in IPOM (Intra-Peritonel-Onlay-Mesh) -position by relaparatomy. Insolvable, monofile, interrupted sutures were used. All patients recovered primarily, and were dismissed within 10 d post OP. No wound healing disorders or signs of postoperative infections occurred. All are free of hernia recurrence in a mean observation time of 22 month (10 - 36). The usage of porcine non-cross-linked biological patches seems feasible for incisional hernia repair after OLT. Wound infections in these patients have been observed with other meshes. Further investigation is needed to prove potential superiority of this biological to the other meshes. © Georg Thieme Verlag KG Stuttgart · New York.

Committee Opinion no. 513: vaginal placement of synthetic mesh for pelvic organ prolapse.

PubMed

2011-12-01

Since 2004, use of synthetic mesh has increased in vaginal surgery for the treatment of pelvic organ prolapse. However, concerns exist about the safety and efficacy of transvaginally placed mesh. Based on the currently available limited data, although many patients undergoing mesh-augmented vaginal repairs heal well without problems, there seems to be a small but significant group of patients who experience permanent and life-altering sequelae, including pain and dyspareunia, from the use of vaginal mesh. The American College of Obstetricians and Gynecologists and the American Urogynecologic Society provide background information on the use of vaginally placed mesh for the treatment of pelvic organ prolapse and offer recommendations for practice.

Vaginal placement of synthetic mesh for pelvic organ prolapse.

PubMed

2012-01-01

Since 2004, use of synthetic mesh has increased in vaginal surgery for the treatment of pelvic organ prolapse. However, concerns exist about the safety and efficacy of transvaginally placed mesh. Based on the currently available limited data, although many patients undergoing mesh-augmented vaginal repairs heal well without problems, there seems to be a small but significant group of patients who experience permanent and life-altering sequelae, including pain and dyspareunia, from the use of vaginal mesh. The American College of Obstetricians and Gynecologists and the American Urogynecologic Society provide background information on the use of vaginally placed mesh for the treatment of pelvic organ prolapse and offer recommendations for practice.

Chronic Quadriceps Tendon Rupture After Total Knee Arthroplasty Augmented With Synthetic Mesh.

PubMed

Ormaza, Amaia; Moreta, Jesús; Mosquera, Javier; de Ugarte, Oskar Sáez; Mozos, José Luis Martinez-de Los

2017-01-01

Tear of the quadriceps tendon after revision or primary total knee arthroplasty is a rare complication, but when it occurs, this injury has serious functional consequences. In complete tears, the outcome of direct repair is unpredictable, and several authors recommend that the suture should be reinforced. Several techniques have been described, including the use of autografts, allografts, and synthetic mesh. The goal of this study was to assess the outcomes of a reconstruction technique augmented with synthetic mesh. A retrospective study was performed involving 3 patients who had chronic partial quadriceps tendon tear after total knee revision. In 2 cases, proximal quadriceps release was performed. When conservative management failed, surgical reconstruction with suture reinforced with synthetic mesh was attempted. The knee was immobilized in full extension for 6 weeks after the surgical procedure. A minimum follow-up of 12 months was required to assess results. All reconstructions showed clinical success at a mean follow-up of 19 months. Mean Knee Society Score improved from 55.7 to 87.3, with average postoperative extensor lag of 3.3° (range, 0°-10°). The mean visual analog scale pain score was 2.3 (range, 0-4). No complications were reported. Synthetic mesh has previously been shown to be an effective treatment for patellar tendon repairs after total knee replacement, but there have been few articles on quadriceps rupture. Surgical reconstruction with synthetic mesh is a viable option that provides good functional outcomes in chronic quadriceps tendon rupture after total knee arthroplasty. [Orthopedics. 2017; 40(1):38-42.]. Copyright 2016, SLACK Incorporated.

Prevention of parastomal hernias with 3D funnel meshes in intraperitoneal onlay position by placement during initial stoma formation.

PubMed

Köhler, G; Hofmann, A; Lechner, M; Mayer, F; Wundsam, H; Emmanuel, K; Fortelny, R H

2016-02-01

In patients with terminal ostomies, parastomal hernias (PSHs) occur on a frequent basis. They are commonly associated with various degrees of complaints and occasionally lead to life-threatening complications. Various strategies and measures have been tested and evaluated, but to date there is a lack of published evidence with regard to the best surgical technique for the prevention of PSH development. We conducted a retrospective analysis of prospectively collected data of eighty patients, who underwent elective permanent ostomy formation between 2009 and 2014 by means of prophylactic implantation of a three-dimensional (3D) funnel mesh in intraperitoneal onlay (IPOM) position. PSH developed in three patients (3.75%). No mesh-related complications were encountered and none of the implants had to be removed. Ostomy-related complications had to be noted in seven (8.75%) cases. No manifestation of ostomy prolapse occurred. Follow-up time was a median 21 (range 3-47) months. The prophylactical implantation of a specially shaped, 3D mesh implant in IPOM technique during initial formation of a terminal enterostomy is safe, highly efficient and comparatively easy to perform. As opposed to what can be achieved with flat or keyhole meshes, the inner boundary areas of the ostomy itself can be well covered and protected from the surging viscera with the 3D implants. At the same time, the vertical, tunnel-shaped part of the mesh provides sufficient protection from an ostomy prolapse. Further studies will be needed to compare the efficacy of various known approaches to PSH prevention.

Outcomes with porcine acellular dermal matrix versus synthetic mesh and suture in complicated open ventral hernia repair.

PubMed

Liang, Mike K; Berger, Rachel L; Nguyen, Mylan Thi; Hicks, Stephanie C; Li, Linda T; Leong, Mimi

2014-10-01

Mesh reinforcement as part of open ventral hernia repair (OVHR) has become the standard of care. However, there is no consensus on the ideal type of mesh to use. In many clinical situations, surgeons are reluctant to use synthetic mesh. Options in these complicated OVHRs include suture repair or the use of biologic mesh such as porcine acellular dermal matrix (PADM). There has been a paucity of controlled studies reporting long-term outcomes with biologic meshes. We hypothesized that compared with synthetic mesh in OVHR, PADM is associated with fewer surgical site infections (SSI) but more seromas and recurrences. Additionally, compared with suture repair, we hypothesized that PADM is associated with fewer recurrences but more SSIs and seromas. A retrospective study was performed of all complicated OVHRs performed at a single institution from 2000-2011. All data were captured from the electronic medical records of the service network. Data were compared in two ways. First, patients who had OVHR with PADM were case-matched with patients having synthetic mesh repairs on the basis of incision class, Ventral Hernia Working Group (VHWG) grade, hernia size, American Society of Anesthesiologists (ASA) class, and emergency status. The PADM cases were also matched with suture repairs on the basis of incision class, hernia grade, duration of the operation, ASA class, and emergency status. Second, we developed a propensity score-adjusted multi-variable logistic regression model utilizing internal resampling to identify predictors of primary outcomes of the overall cohort. The U.S. Centers for Disease Control and Prevention (CDC) definition of SSI was utilized; seromas and recurrences were defined and tracked similarly for all patients. Data were analyzed using the McNemar, X(2), paired two-tailed Student t, or Mann-Whitney U test as appropriate. A total of 449 complicated OVHR cases were reviewed for a median follow up of 61 mos (range 1-143 mos): 94 patients had PADM repairs, whereas 154 patients underwent synthetic mesh repairs, and 201 had suture repairs. The 40 PADM repairs were matched to synthetic repairs and 59 were matched to suture repairs. The PADM repairs that could not be well matched (n=54 unmatched for synthetic repairs, 35 unmatched for suture repairs) were characterized generally by larger hernias, VHWG grades of 3 or 4, and incision class 3 or 4 with longer operative durations and more ASA class 4 cases. The patients were well matched. Comparing PADM with synthetic mesh, there was no difference in SSI (20% vs. 35%; p=0.29), seromas (32.5% vs. 15%; p=0.17), mesh explantations (5% vs. 15%, p=0.28), readmissions within 90 d (37.5% vs. 45%; p=1.00), or recurrence (8.5% vs. 22.5%; p=0.15). Compared with suture repair, patients with PADM had fewer recurrences (11.9% vs. 33.9%; p<0.01) and more seromas (32.2% vs. 10.2%; p=0.02), but a similar number of SSIs (23.7% vs. 39.0%; p=0.19) and 90-d readmissions (35.6% vs. 39.0%; p=0.88). Propensity score-adjusted multi-variable logistic regression of the entire cohort corroborated the results of the case-matched patients. The PADM repair of complicated OVHR resulted in fewer recurrences, more seromas, and no difference in SSI compared with suture repair. Although no reduction in SSI was identified with the use of PADM rather than synthetic mesh or suture for OVHR, the meaning of this finding is unclear, as this case-controlled study was underpowered and limited by selection bias. According to our data, 280 patients would have been needed to identify a clinically significant difference in the primary outcome of SSI as well as secondary outcomes of mesh explantation and recurrence (α=0.05; β=0.20). A randomized trial is warranted to compare PADM with synthetic mesh in complicated OVHR.

Surgical outcomes and quality of life post-synthetic mesh-augmented repair for pelvic organ prolapse in the Chinese population.

PubMed

Sun, Xiuli; Zhang, Xiaowei; Wang, Jianliu

2014-02-01

To investigate the surgical outcomes, urinary incontinence and quality of life (QOL) of patients with pelvic organ prolapse after synthetic mesh-augmented repair in the Chinese population. This is a retrospective study of women who underwent synthetic mesh-augmented repair. Surgical outcomes were investigated by recurrence rate of prolapse and Organ Prolapse Quantification, and QOL by Pelvic Floor Impact Questionnaire-7 (PFIQ-7) and Pelvic Floor Distress Inventory-20 (PFDI-20). The sex life quality was evaluated by Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-31 (PISQ-31). Eighty-three patients completed the entire study. Anatomical success was 90.36%. Of patients with preoperative stress urinary incontinence, 91.89% claimed that the incontinence symptoms were completely relieved. The 6-month PFDI-20 and PFIQ-7 scores were significantly decreased, indicating that improved QOL occurs. However, the PISQ-31 showed no significant difference between preoperative and postoperative data in sex life quality. The synthetic polypropylene mesh is effective in treating POP and may improve QOL with no significant difference in the sexual life postoperatively. De novo stress urinary incontinence may occur after synthetic mesh-augmented repair. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

Mesh morphing for finite element analysis of implant positioning in cementless total hip replacements.

PubMed

Bah, Mamadou T; Nair, Prasanth B; Browne, Martin

2009-12-01

Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 degrees between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements.

The complete digital workflow in fixed prosthodontics: a systematic review.

PubMed

Joda, Tim; Zarone, Fernando; Ferrari, Marco

2017-09-19

The continuous development in dental processing ensures new opportunities in the field of fixed prosthodontics in a complete virtual environment without any physical model situations. The aim was to compare fully digitalized workflows to conventional and/or mixed analog-digital workflows for the treatment with tooth-borne or implant-supported fixed reconstructions. A PICO strategy was executed using an electronic (MEDLINE, EMBASE, Google Scholar) plus manual search up to 2016-09-16 focusing on RCTs investigating complete digital workflows in fixed prosthodontics with regard to economics or esthetics or patient-centered outcomes with or without follow-up or survival/success rate analysis as well as complication assessment of at least 1 year under function. The search strategy was assembled from MeSH-Terms and unspecific free-text words: {(("Dental Prosthesis" [MeSH]) OR ("Crowns" [MeSH]) OR ("Dental Prosthesis, Implant-Supported" [MeSH])) OR ((crown) OR (fixed dental prosthesis) OR (fixed reconstruction) OR (dental bridge) OR (implant crown) OR (implant prosthesis) OR (implant restoration) OR (implant reconstruction))} AND {("Computer-Aided Design" [MeSH]) OR ((digital workflow) OR (digital technology) OR (computerized dentistry) OR (intraoral scan) OR (digital impression) OR (scanbody) OR (virtual design) OR (digital design) OR (cad/cam) OR (rapid prototyping) OR (monolithic) OR (full-contour))} AND {("Dental Technology" [MeSH) OR ((conventional workflow) OR (lost-wax-technique) OR (porcelain-fused-to-metal) OR (PFM) OR (implant impression) OR (hand-layering) OR (veneering) OR (framework))} AND {(("Study, Feasibility" [MeSH]) OR ("Survival" [MeSH]) OR ("Success" [MeSH]) OR ("Economics" [MeSH]) OR ("Costs, Cost Analysis" [MeSH]) OR ("Esthetics, Dental" [MeSH]) OR ("Patient Satisfaction" [MeSH])) OR ((feasibility) OR (efficiency) OR (patient-centered outcome))}. Assessment of risk of bias in selected studies was done at a 'trial level' including random sequence generation, allocation concealment, blinding, completeness of outcome data, selective reporting, and other bias using the Cochrane Collaboration tool. A judgment of risk of bias was assigned if one or more key domains had a high or unclear risk of bias. An official registration of the systematic review was not performed. The systematic search identified 67 titles, 32 abstracts thereof were screened, and subsequently, three full-texts included for data extraction. Analysed RCTs were heterogeneous without follow-up. One study demonstrated that fully digitally produced dental crowns revealed the feasibility of the process itself; however, the marginal precision was lower for lithium disilicate (LS2) restorations (113.8 μm) compared to conventional metal-ceramic (92.4 μm) and zirconium dioxide (ZrO2) crowns (68.5 μm) (p < 0.05). Another study showed that leucite-reinforced glass ceramic crowns were esthetically favoured by the patients (8/2 crowns) and clinicians (7/3 crowns) (p < 0.05). The third study investigated implant crowns. The complete digital workflow was more than twofold faster (75.3 min) in comparison to the mixed analog-digital workflow (156.6 min) (p < 0.05). No RCTs could be found investigating multi-unit fixed dental prostheses (FDP). The number of RCTs testing complete digital workflows in fixed prosthodontics is low. Scientifically proven recommendations for clinical routine cannot be given at this time. Research with high-quality trials seems to be slower than the industrial progress of available digital applications. Future research with well-designed RCTs including follow-up observation is compellingly necessary in the field of complete digital processing.

Electrical characteristic of the titanium mesh electrode for transcutaneous intrabody communication to monitor implantable artificial organs.

PubMed

Okamoto, Eiji; Kikuchi, Sakiko; Mitamura, Yoshinori

2016-09-01

We have developed a tissue-inducing electrode using titanium mesh to obtain mechanically and electrically stable contact with the tissue for a new transcutaneous communication system using the human body as a conductive medium. In this study, we investigated the electrical properties of the titanium mesh electrode by measuring electrode-tissue interface resistance in vivo. The titanium mesh electrode (Hi-Lex Co., Zellez, Hyogo, Japan) consisted of titanium fibers (diameter of 50 μm), and it has an average pore size of 200 μm and 87 % porosity. The titanium mesh electrode has a diameter of 5 mm and thickness of 1.5 mm. Three titanium mesh electrodes were implanted separately into the dorsal region of the rat. We measured the electrode-electrode impedance using an LCR meter for 12 weeks, and we calculated the tissue resistivity and electrode-tissue interface resistance. The electrode-tissue interface resistance of the titanium mesh electrode decreased slightly until the third POD and then continuously increased to 75 Ω. The electrode-tissue interface resistance of the titanium mesh electrode is stable and it has lower electrode-tissue interface resistance than that of a titanium disk electrode. The extracted titanium mesh electrode after 12 weeks implantation was fixed in 10 % buffered formalin solution and stained with hematoxylin-eosin. Light microscopic observation showed that the titanium mesh electrode was filled with connective tissue, inflammatory cells and fibroblasts with some capillaries in the pores of the titanium mesh. The results indicate that the titanium mesh electrode is a promising electrode for the new transcutaneous communication system.

Evaluation and management of complications from synthetic mesh after pelvic reconstructive surgery: a multicenter study.

PubMed

Abbott, Sara; Unger, Cecile A; Evans, Janelle M; Jallad, Karl; Mishra, Kevita; Karram, Mickey M; Iglesia, Cheryl B; Rardin, Charles R; Barber, Matthew D

2014-02-01

The purpose of this study was to describe the evaluation and management of synthetic mesh-related complications after surgery for stress urinary incontinence (SUI) and/or pelvic organ prolapse (POP). We conducted a multicenter, retrospective analysis of women who attended 4 US tertiary referral centers for evaluation of mesh-related complications after surgery for SUI and/or POP from January 2006 to December 2010. Demographic, clinical, and surgical data were abstracted from the medical record, and complications were classified according to the Expanded Accordion Severity Classification. Three hundred forty-seven patients sought management of synthetic mesh-related complications over the study period. Index surgeries were performed for the following indications: SUI (sling only), 49.9%; POP (transvaginal mesh [TVM] or sacrocolpopexy only), 25.6%; and SUI + POP (sling + TVM or sacrocolpopexy), 24.2%. Median time to evaluation was 5.8 months (range, 0-65.2). Thirty percent of the patients had dyspareunia; 42.7% of the patients had mesh erosion; and 34.6% of the patients had pelvic pain. Seventy-seven percent of the patients had a grade 3 or 4 (severe) complication. Patients with TVM or sacrocolpopexy were more likely to have mesh erosion and vaginal symptoms compared with sling only. The median number of treatments for mesh complications was 2 (range, 1-9); 60% of the women required ≥2 interventions. Initial treatment intervention was surgical for 49% of subjects. Of those treatments that initially were managed nonsurgically, 59.3% went on to surgical intervention. Most of the women who seek management of synthetic mesh complication after POP or SUI surgery have severe complications that require surgical intervention; a significant proportion require >1 surgical procedure. The pattern of complaints differs by index procedure. Copyright © 2014 Mosby, Inc. All rights reserved.

Towards retrievable vascularized bioartificial pancreas: induction and long-lasting stability of polymeric mesh implant vascularized with the help of acidic and basic fibroblast growth factors and hydrogel coating.

PubMed

Prokop, A; Kozlov, E; Nun Non, S; Dikov, M M; Sephel, G C; Whitsitt, J S; Davidson, J M

2001-01-01

We seek to improve existing methodologies for allogenic grafting of pancreatic islets. The lack of success of encapsulated transplanted islets inside the peritoneal cavity is presently attributed to poor vascularization of the implant. A thick, fibrotic capsule often surrounds the graft, limiting survival. We have tested the hypothesis that neovascularization of the graft material can be induced by the addition of proper angiogenic factors embedded within a polymeric coat. Biocompatible and nonresorbable meshes coated with hydrophilic polymers were implanted in rats and harvested after 1-, 6-, and 12-week intervals. The implant response was assessed by histological observations on the degree of vascularity, fibrosis, and inflammation. Macrostructural geometry of meshes was conducive to tissue ingrowth into the interstitial space between the mesh filaments. Hydrogel coating with incorporated acidic or basic FGF in an electrostatic complex with polyelectrolytes and/or with heparin provided a sustained slow release of the angiogenic growth factor. Anti-factor VIII and anti-collagen type IV antibodies and a GSL I-B4 lectin were used to measure the extent of vascularization. Vigorous and persistent vascularization radiated several hundred microns from the implant. The level of vascularization should provide a sufficient diffusion of nutrients and oxygen to implanted islets. Based on our observations, stable vascularization may require a sustained angiogenic signal to allow for the development of a permanent implant structure.

Cross-linked xenogenic collagen implantation in the sheep model for vaginal surgery.

PubMed

Endo, Masayuki; Urbankova, Iva; Vlacil, Jaromir; Sengupta, Siddarth; Deprest, Thomas; Klosterhalfen, Bernd; Feola, Andrew; Deprest, Jan

The properties of meshes used in reconstructive surgery affect the host response and biomechanical characteristics of the grafted tissue. Whereas durable synthetics induce a chronic inflammation, biological grafts are usually considered as more biocompatible. The location of implantation is another determinant of the host response: the vagina is a different environment with specific function and anatomy. Herein, we evaluated a cross-linked acellular collagen matrix (ACM), pretreated by the anti-calcification procedure ADAPT® in a sheep model for vaginal surgery. Ten sheep were implanted with a cross-linked ACM, and six controls were implanted with a polypropylene (PP; 56 g/m 2 ) control. One implant was inserted in the lower rectovaginal septum, and one was used for abdominal wall defect reconstruction. Grafts were removed after 180 days; all graft-related complications were recorded, and explants underwent bi-axial tensiometry and contractility testing. Half of ACM-implanted animals had palpable induration in the vaginal implantation area, two of these also on the abdominal implant. One animal had a vaginal exposure. Vaginal ACMs were 63 % less stiff compared to abdominal ACM explants ( p  = 0.01) but comparable to vaginal PP explants. Seven anterior vaginal ACM explants showed areas of graft degradation on histology. There was no overall difference in vaginal contractility. Considering histologic degradation in the anterior vaginal implant as representative for the host, posterior ACM explants of animals with degradation had a 60 % reduced contractility as compared to PP ( p  = 0.048). Three abdominal implants showed histologic degradation; those were more compliant than non-degraded implants. Vaginal implantation with ACM was associated with graft-related complications (GRCs) and biomechanical properties comparable to PP. Partially degraded ACM had a decreased vaginal contractility.

Mesh electronics: a new paradigm for tissue-like brain probes.

PubMed

Hong, Guosong; Yang, Xiao; Zhou, Tao; Lieber, Charles M

2018-06-01

Existing implantable neurotechnologies for understanding the brain and treating neurological diseases have intrinsic properties that have limited their capability to achieve chronically-stable brain interfaces with single-neuron spatiotemporal resolution. These limitations reflect what has been dichotomy between the structure and mechanical properties of living brain tissue and non-living neural probes. To bridge the gap between neural and electronic networks, we have introduced the new concept of mesh electronics probes designed with structural and mechanical properties such that the implant begins to 'look and behave' like neural tissue. Syringe-implanted mesh electronics have led to the realization of probes that are neuro-attractive and free of the chronic immune response, as well as capable of stable long-term mapping and modulation of brain activity at the single-neuron level. This review provides a historical overview of a 10-year development of mesh electronics by highlighting the tissue-like design, syringe-assisted delivery, seamless neural tissue integration, and single-neuron level chronic recording stability of mesh electronics. We also offer insights on unique near-term opportunities and future directions for neuroscience and neurology that now are available or expected for mesh electronics neurotechnologies. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The osteoplastic effectiveness of the implants made of mesh titanium nickelide constructs

PubMed Central

Irianov, Iurii Mikhailovich; Diuriagina, Olga Vladimirovna; Karaseva, Tatiana Iurevna; Karasev, Evgenii Anatolevich

2014-01-01

The purpose of the work was to study the features of reparative osteogenesis for filling the defect of tubular bone under implantation of mesh titanium nickelide constructs. Tibial fenestrated defect was modeled experimentally in 30 Wistar pubertal rats, followed by implant intramedullary insertion. The techniques of radiography, scanning electron microscopy and X-ray electron probe microanalysis were used. The mesh implant of titanium nickelide has been established to possess biocompatibility, osteoconductive and osteoinductive properties, the zone of osteogenesis and angiogenesis is created around it, bone cover is formed. Osteointegration of the implant occurs early, by 7 days after surgery, and by 30 days after surgery organotypical re-modelling of the regenerated bone takes place, as well as the defect is filled with lamellar bone tissue by the type of bone wound primary adhesion. By 30 days after surgery mineral content of the regenerated bone tissue approximates to the composition of intact cortex mineral phase. PMID:24579962

Long-term results after artificial iris implantation in patients with aniridia.

PubMed

Rickmann, Annekatrin; Szurman, Peter; Januschowski, Kai; Waizel, Maria; Spitzer, Martin S; Boden, Karl T; Szurman, Gesine B

2016-07-01

The custom-made, flexible artificial iris developed by HumanOptics and Koch can reconstruct the anterior segment of patients with aniridia. The aim of this study was to evaluate the long-term clinical outcome and complication spectrum after artificial iris implantation and the role of the embedded fiber mesh in view of specific complications. In this retrospective interventional case series, patients received an artificial iris between 2004 and 2013. Only eyes with a minimum follow-up period of 2 years were included. Indications were congenital, traumatic, or iatrogenic aniridia. The artificial iris was used either with or without embedded fiber mesh for partial or full prostheses. We included 34 patients (mean age 48.8 years; SD ±17.2) with a mean follow-up of 50.0 months (SD ±18.9 months). No repositioning of prostheses was necessary. In cases of keratopathy (17.6 %) visual function increased from baseline mean 1.6 logMAR (SD ±0.7) to 1.2 logMAR (SD ±0.7) after artificial iris implantation. The remaining iris tissue darkened during the follow-up in 23.5 % (83.3 % with and 10.7 % without mesh), 8.8 % developed glaucoma (50 % with and 0 % without mesh) and 14.7 % needed consecutive surgery after prostheses implantation (50 % with and 7.1 % without mesh). In three out of seven trauma cases (42.9 %) silicone oil was spilled into the anterior chamber after 2.5 years on average. The artificial iris prosthesis revealed a good clinical outcome in terms of long-term stability, cosmetic appearance, visual function, and represents a good functional iris diaphragm for compartmentalisation. Complications such as glaucoma, darkening of iris tissue, and need for consecutive anterior segment surgery are clearly associated with implants with integrated fiber mesh, but not to those without. Hence, the use of full iris prostheses without embedded fiber mesh, even in cases with remnant iris, and the use of slightly smaller implants than officially recommended may be beneficial.

Comparative study of safety and efficacy of synthetic surgical glue for mesh fixation in ventral rectopexy.

PubMed

Silveira, Raquel Kelner; Domingie, Sophie; Kirzin, Sylvain; de Melo Filho, Djalma Agripino; Portier, Guillaume

2017-10-01

Ventral mesh rectopexy (VMR) is a surgical option to treat rectal prolapse with pelvic floor dysfunction (PFD). Using synthetic surgical glue to fix the mesh to the anterior rectal wall after ventral dissection could be advantageous in comparison with sutured or stapled fixation. This study aimed to evaluate the safety and efficacy of synthetic surgical glue for mesh fixation compared with suture mesh fixation in VMR. This observational cohort study is a retrospective analysis conducted in a University Hospital Pelvic Surgery Center. All consecutive female patients (n = 176) who underwent laparoscopic or laparotomic VMR between January 2009 and December 2014 were included. Two groups were defined based on mesh fixation technique of the rectal wall: VMR with synthetic glue (n = 66) and VMR with suture (n = 110). The recurrence-free survival after VMR was determined by Kaplan-Meier method and multivariate analysis by Cox regression. Short-term postoperative complications, postoperative symptom improvement, the need for complementary treatment postoperatively, and procedure length were evaluated. A total of 176 females patients (mean age, 58.6 ± 13.7 years) underwent VMR with synthetic mesh. Mean recurrence-free survivals after VMR were 17.16 (CI 95% 16.54-17.80) and 17.33 (CI 95% 16.89-17.77) months in the glue group and the suture group, respectively (p > 0.05). Cox regression identified an independent effect on the recurrence risk of the external rectal prolapse, alone, or in combination with other anatomical abnormalities (HR = 0.37; CI 95% 0.14-0.93; p = 0.03). There was no significant difference of short-term postoperative morbidity, procedure length, postoperative symptom improvement, or need for complementary treatment postoperatively between suture versus glue groups (all p > 0.05). Use of glue to fix the mesh in VMR was safe and had no impact on outcomes. External prolapse was the unique significant predictive factor for recurrence.

21 CFR 870.3650 - Pacemaker polymeric mesh bag.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

21 CFR 870.3650 - Pacemaker polymeric mesh bag.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

21 CFR 870.3650 - Pacemaker polymeric mesh bag.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

21 CFR 870.3650 - Pacemaker polymeric mesh bag.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

Investigation on Tensile Fatigue Characteristics of Meshed GUM Metal Plates for Bone Graft Applications

NASA Astrophysics Data System (ADS)

Sekiguchi, Koki; He, Jianmei

2017-11-01

GUM Metal has characteristics of lower elasticity rigidity, large elastic deformation, higher strength and biocompatibility etc. When it is used for implant applications, there is still problem like overloading on the natural-bone because of its high rigidity compared with the human bones. Therefore, the purpose of this study is to create more flexible meshed plates for implant applications from the viewpoints of elastic rigidity and volume density. Basic mesh shapes are designed, devised and applied for meshed GUM Metal plates using three dimensional (3D) CAD tools. Experimental evaluation on tensile fatigue characteristics of meshed GUM Metal plate specimens are carried out. Analytical approaches on stress evaluation are also executed through finite element method to obtain the S-N curve for fatigue characteristic evaluation.

Effect of platelet-rich plasma on polypropylene meshes implanted in the rabbit vagina: histological analysis.

PubMed

Parizzi, Natália Gomes; Rubini, Oscar Ávila; Almeida, Silvio Henrique Maia de; Ireno, Lais Caetano; Tashiro, Roger Mitio; Carvalho, Victor Hugo Tolotto de

2017-01-01

The polypropylene mesh (PPM) is used in many surgical interventions because of its good incorporation and accessibility. However, potential mesh-related complications are common. Platelet-rich plasma (PRP) improves the healing of wounds and is inexpensive. Thus, the purpose of this study was to analyze the effect of the PRP-gel coating of a PPM on inflammation, production of collagen, and smooth muscle in the rabbit vagina. The intervention consisted of a 1.5cm incision and divulsion of the vaginal mucosa for the implantation of a PRP-coated PPM. The PRP-coated mesh was implanted in 15 rabbits, and in the second group, the same implant was used without the PRP coating. In the sham group, the intervention consisted of the incision, divulsion, and suture. The rabbits were euthanized at 7, 30 and 90 days, and full-thickness sagittal sections of the posterior vaginal wall and rectum were scored. The inflammatory infiltrate was evaluated using hematoxylin and eosin staining. The Sirius Red stain was used to examine deposition of collagen I and III, and Masson's trichrome staining was used to visualize the smooth muscle. The group with PRP-coated meshes had a lower inflammatory infiltrate count at 30 days. Deposition of collagen III increased with the use of PRP-coating at 90 days. The area of inflammatory infiltrate was significantly increased in the group without the PRP-coated mesh at 30 days but not in the group with the PRPcoated mesh, indicating a less intense inflammatory response. In addition, a significant increase in collagen III occurred at 90 days. Copyright® by the International Brazilian Journal of Urology.

Histologic Inflammatory Response to Transvaginal Polypropylene Mesh: A Systematic Review.

PubMed

Thomas, Dominique; Demetres, Michelle; Anger, Jennifer T; Chughtai, Bilal

2018-01-01

To evaluate the inflammatory response following transvaginal implantation of polypropylene (PP) mesh. A comprehensive literature search was performed in the following databases from inception in April 2017: Ovid MEDLINE, Ovid EMBASE, and The Cochrane Library (Wiley). The studies retrieved were screened for eligibility against predefined inclusion and exclusion criteria. Twenty-three articles were included in this review. Following the implantation of PP mesh, there are immediate and local inflammatory responses. PP mesh elicits an inflammatory response that decreases over time; however, no studies documented a complete resolution. Further studies are needed to determine if there is a complete resolution of inflammation or if it persists. Copyright © 2017 Elsevier Inc. All rights reserved.

Assessment of adhesion formation after laparoscopic intraperitoneal implantation of Dynamesh IPOM mesh

PubMed Central

Jałyński, Marek; Piskorz, Łukasz; Brocki, Marian

2013-01-01

Introduction Formation of adhesions after laparoscopic hernia repair using the intra-peritoneal onlay mesh (IPOM) procedure can lead to intestinal obstruction or mesh erosion into intestinal lumen. The aims of this study included: measurement of adhesion formation with Dynamesh IPOM after laparoscopic intraperitoneal implantation, and assessment of the occurrence of isolated adhesions at the fastening sites of slowly absorbable sutures. Material and methods Twelve healthy pigs underwent laparoscopic implantation of 2 Dynamesh IPOM mesh fragments each, one was fastened with PDSII, and the other with Maxon sutures. An assessment of adhesion formation was carried out after 6 weeks and included an evaluation of surface area, hardness according to the Zhulke scale, and index values. The occurrence of isolated adhesions at slowly absorbable suture fixation points was also analyzed. Results Adhesions were noted in 83.3% of Dynamesh IPOM meshes. Adhesions covered on average 37.7% of the mesh surface with mean hardness 1.46 and index value 78.8. In groups fixed with PDS in comparison to Maxon sutures adhesions covered mean 31.6% vs. 42.5% (p = 0.62) of the mesh surface, mean hardness was 1.67 vs.1.25 (p = 0.34) and index 85.42 vs. 72.02 (p = 0.95). Conclusions The Dynamesh IPOM mesh, in spite of its anti-adhesive layer of PVDF, does not prevent the formation of adhesions. Adhesion hardness, surface area, and index values of the Dynamesh IPOM mesh are close to the mean values of these parameters for other commercially available 2-layer meshes. Slowly absorbable sutures used for fastening did not increase the risk of adhesion formation. PMID:23847671

Biocompatibility and tissue integration of a novel shape memory surgical mesh for ventral hernia: In vivo animal studies

PubMed Central

Zimkowski, Michael M.; Rentschler, Mark E.; Schoen, Jonathan A.; Mandava, Nageswara; Shandas, Robin

2014-01-01

Approximately 400,000 ventral hernia repair surgeries are performed each year in the United States. Many of these procedures are performed using laparoscopic minimally invasive techniques and employ the use of surgical mesh. The use of surgical mesh has been shown to reduce recurrence rates compared to standard suture repairs. The placement of surgical mesh in a ventral hernia repair procedure can be challenging, and may even complicate the procedure. Others have attempted to provide commercial solutions to the problems of mesh placement, but these have not been well accepted by the clinical community. In this article, two versions of shape memory polymer (SMP)-modified surgical mesh, and unmodified surgical mesh, were compared by performing laparoscopic manipulation in an acute porcine model. Also, SMP-integrated polyester surgical meshes were implanted in four rats for 30–33 days to evaluate chronic biocompatibility and capacity for tissue integration. Porcine results show that the modified mesh provides a controlled, temperature-activated, automated deployment when compared to an unmodified mesh. In rats, results indicate that implanted SMP-modified meshes exhibit exceptional biocompatibility and excellent integration with surrounding tissue with no noticeable differences from the unmodified counterpart. This article provides further evidence that an SMP-modified surgical mesh promises reduction in surgical placement time and that such a mesh is not substantially different from unmodified meshes in chronic biocompatibility. PMID:24327401

Comparison of titanium mesh implants with PLA-hydroxyapatite coatings for maxillofacial cancer reconstruction

NASA Astrophysics Data System (ADS)

Tverdokhlebov, S. I.; Choinzonov, E. L.; Kolokolova, O. V.; Cherdyntseva, N. V.

2016-08-01

Since 2013 physics of TPU and oncologists from the TCRI with participation of the "ConMet" company (Moscow) and the "Sintel" company (Tomsk Special Economic Zone resident) have been working on the theme entitled "Development of the composite implants for reconstructive surgery of a craniofacial areas of the traumatological and oncological patients" supported with the Federal Program "R&D, part 1.3". The goal was to develop the maxillo-facial implants on the basis of the transformable titanium mesh with PLA & hydroxyapatite coating. According to the Contract No. 14.578.21.0031, the team of developers had to start supplying these advanced implants to the industrial partners up to 2017. This research was supported with the preliminary market researches by the ISPMS SB RAS and the TP "MF". The stages of preliminary market researches were: 1) research of the Worldwide CMF market; 2) forecasting the BRIC CMF market up to 2020; 3) the total Russian market (epidemiology) estimation as a sum of official calculations and statistics; 4) looking for the best foreign analogue prices, comparing their and our implant properties; 5) search for the best Russian analogues; 6) the investigation of the world patent database Espacenet for the last years, and finding the owners and applicants of patents of CMF osteosynthesis plates on the basis of titanium coated with PLA & hydroxyapatite; 7) comparison of the domestic implants, and making conclusions. Several variants of the meshes have got the equal quality with the best foreign and Russian implants. The closest analogues were titanium, polyethylene, PEEK composite meshes suited to the patient shape by the Synthes company in 2014, and the only hybrid titanium "Grey" implant with layers of gelatin, dextran, collagen, HAP & BMP-2 was found. This implant was produced by Russian institution, and it was mentioned in the report on clinical trials by L.A. Pavlova et al., 2014 [1]. There are no manufacturers of the coated implants in Russia. The average price of the similar foreign implants varies from 12 up to 40 USA per 1 cm2. It may be concluded that our implant is of the same quality as the best Russian and foreign implants.

Next-generation biomedical implants using additive manufacturing of complex, cellular and functional mesh arrays.

PubMed

Murr, L E; Gaytan, S M; Medina, F; Lopez, H; Martinez, E; Machado, B I; Hernandez, D H; Martinez, L; Lopez, M I; Wicker, R B; Bracke, J

2010-04-28

In this paper, we examine prospects for the manufacture of patient-specific biomedical implants replacing hard tissues (bone), particularly knee and hip stems and large bone (femoral) intramedullary rods, using additive manufacturing (AM) by electron beam melting (EBM). Of particular interest is the fabrication of complex functional (biocompatible) mesh arrays. Mesh elements or unit cells can be divided into different regions in order to use different cell designs in different areas of the component to produce various or continually varying (functionally graded) mesh densities. Numerous design elements have been used to fabricate prototypes by AM using EBM of Ti-6Al-4V powders, where the densities have been compared with the elastic (Young) moduli determined by resonant frequency and damping analysis. Density optimization at the bone-implant interface can allow for bone ingrowth and cementless implant components. Computerized tomography (CT) scans of metal (aluminium alloy) foam have also allowed for the building of Ti-6Al-4V foams by embedding the digital-layered scans in computer-aided design or software models for EBM. Variations in mesh complexity and especially strut (or truss) dimensions alter the cooling and solidification rate, which alters the alpha-phase (hexagonal close-packed) microstructure by creating mixtures of alpha/alpha' (martensite) observed by optical and electron metallography. Microindentation hardness measurements are characteristic of these microstructures and microstructure mixtures (alpha/alpha') and sizes.

Indications, Contraindications, and Complications of Mesh in Surgical Treatment of Pelvic Organ Prolapse

PubMed Central

Ellington, David R.; Richter, Holly E.

2013-01-01

Women are seeking care for pelvic organ prolapse (POP) in increasing numbers and a significant proportion of them will undergo a second repair for recurrence. This has initiated interest by both surgeons and industry to utilize and design prosthetic mesh materials to help augment longevity of prolapse repairs. Unfortunately, the introduction of transvaginal synthetic mesh kits for use in women was done without the benefit of Level 1 data to determine its utility compared to native tissue repair. This report summarizes the potential benefit/risks of transvaginal synthetic mesh use for POP and recommendations regarding its continued use. PMID:23563869

Microarc oxidation coating covered Ti implants with micro-scale gouges formed by a multi-step treatment for improving osseointegration.

PubMed

Bai, Yixin; Zhou, Rui; Cao, Jianyun; Wei, Daqing; Du, Qing; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu

2017-07-01

The sub-microporous microarc oxidation (MAO) coating covered Ti implant with micro-scale gouges has been fabricated via a multi-step MAO process to overcome the compromised bone-implant integration. The as-prepared implant has been further mediated by post-heat treatment to compare the effects of -OH functional group and the nano-scale orange peel-like morphology on osseointegration. The bone regeneration, bone-implant contact interface, and biomechanical push-out force of the modified Ti implant have been discussed thoroughly in this work. The greatly improved push-out force for the MAO coated Ti implants with micro-scale gouges could be attributed to the excellent mechanical interlocking effect between implants and biologically meshed bone tissues. Attributed to the -OH functional group which promotes synostosis between the biologically meshed bone and the gouge surface of implant, the multi-step MAO process could be an effective strategy to improve the osseointegration of Ti implant. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-term follow-up of treatment for synthetic mesh complications.

PubMed

Hansen, Brooke L; Dunn, Guinn Ellen; Norton, Peggy; Hsu, Yvonne; Nygaard, Ingrid

2014-01-01

The objectives of this study are (1) to describe the presenting symptoms, findings, and treatment and (2) to describe the self-reported improvement and function at least 6 months after presentation in women presenting to 1 urogynecology division for complications associated with synthetic vaginal mesh. Women evaluated between 2006 and 2011 were identified by diagnostic codes. We abstracted information from the medical record and attempted to contact all women to complete a follow-up telephone survey questionnaire consisting of several validated instruments. A total of 111 women were evaluated for complications associated with synthetic vaginal mesh. The mean interval from index surgery was 2.4 years. Of these, 84% were referred from outside hospitals. Index surgeries included vaginal mesh kits/vaginally placed mesh (47%), midurethral mesh slings (37%), abdominally placed vaginal mesh (11%), and vaginal mesh kit with concomitantly placed mesh sling (5%). The most common complications were extrusion (65%), contraction (17%), and chronic pelvic pain (16%). A total of 98 women underwent some type of treatment (85 surgical) by urogynecologists, pelvic pain specialists, or physical therapists. Eighty-four (76%) provided follow-up information at mean interval since presentation of 2.3 years. At follow-up, the mean (SD) Pelvic Floor Distress Inventory score was 98 (67), the mean (SD) EQ-5D index score was 0.69 (0.23), and 22% reported vaginal discharge, 15% vaginal bleeding or spotting, and 45% sexual abstinence due to problems related to mesh. A total of 71% reported being overall better, whereas 29% were the same or worse. Two years after tertiary care level multidisciplinary treatment of vaginal mesh complications, many women still report symptoms that negatively impact their quality of life.

Extracellular matrix regenerative graft attenuates the negative impact of polypropylene prolapse mesh on vagina in rhesus macaque.

PubMed

Liang, Rui; Knight, Katrina; Barone, William; Powers, Robert W; Nolfi, Alexis; Palcsey, Stacy; Abramowitch, Steven; Moalli, Pamela A

2017-02-01

The use of wide pore lightweight polypropylene mesh to improve anatomical outcomes in the surgical repair of prolapse has been hampered by mesh complications. One of the prototype prolapse meshes has been found to negatively impact the vagina by inducing a decrease in smooth muscle volume and contractility and the degradation of key structural proteins (collagen and elastin), resulting in vaginal degeneration. Recently, bioscaffolds derived from extracellular matrix have been used to mediate tissue regeneration and have been widely adopted in tissue engineering applications. Here we aimed to: (1) define whether augmentation of a polypropylene prolapse mesh with an extracellular matrix regenerative graft in a primate sacrocolpopexy model could mitigate the degenerative changes; and (2) determine the impact of the extracellular matrix graft on vagina when implanted alone. A polypropylene-extracellular matrix composite graft (n = 9) and a 6-layered extracellular matrix graft alone (n = 8) were implanted in 17 middle-aged parous rhesus macaques via sacrocolpopexy and compared to historical data obtained from sham (n = 12) and the polypropylene mesh (n = 12) implanted by the same method. Vaginal function was measured in passive (ball-burst test) and active (smooth muscle contractility) mechanical tests. Vaginal histomorphologic/biochemical assessments included hematoxylin-eosin and trichrome staining, immunofluorescent labeling of α-smooth muscle actin and apoptotic cells, measurement of total collagen, collagen subtypes (ratio III/I), mature elastin, and sulfated glycosaminoglycans. Statistical analyses included 1-way analysis of variance, Kruskal-Wallis, and appropriate post-hoc tests. The host inflammatory response in the composite mesh-implanted vagina was reduced compared to that following implantation with the polypropylene mesh alone. The increase in apoptotic cells observed with the polypropylene mesh was blunted in the composite (overall P < .001). Passive mechanical testing showed inferior parameters for both polypropylene mesh alone and the composite compared to sham whereas the contractility and thickness of smooth muscle layer in the composite were improved with a value similar to sham, which was distinct from the decreases observed with polypropylene mesh alone. Biochemically, the composite had similar mature elastin content, sulfated glycosaminoglycan content, and collagen subtype III/I ratio but lower total collagen content when compared to sham (P = .011). Multilayered extracellular matrix graft alone showed overall comparable values to sham in aspects of the biomechanical, histomorphologic, or biochemical endpoints of the vagina. The increased collagen subtype ratio III/I with the extracellular matrix graft alone (P = .033 compared to sham) is consistent with an ongoing active remodeling response. Mesh augmentation with a regenerative extracellular matrix graft attenuated the negative impact of polypropylene mesh on the vagina. Application of the extracellular matrix graft alone had no measurable negative effects suggesting that the benefits of this extracellular matrix graft occur when used without a permanent material. Future studies will focus on understanding mechanisms. Copyright © 2016. Published by Elsevier Inc.

Extracellular matrix regenerative graft attenuates the negative impact of polypropylene prolapse mesh on vagina in rhesus macaque

PubMed Central

Liang, Rui; Knight, Katrina; Barone, William; Powers, Robert W.; Nolfi, Alexis; Palcsey, Stacy; Abramowitch, Steven; Moalli, Pamela A.

2016-01-01

BACKGROUND The use of wide pore lightweight polypropylene mesh to improve anatomical outcomes in the surgical repair of prolapse has been hampered by mesh complications. One of the prototype prolapse meshes has been found to negatively impact the vagina by inducing a decrease in smooth muscle volume and contractility and the degradation of key structural proteins (collagen and elastin), resulting in vaginal degeneration. Recently, bioscaffolds derived from extracellular matrix have been used to mediate tissue regeneration and have been widely adopted in tissue engineering applications. OBJECTIVE Here we aimed to: (1) define whether augmentation of a polypropylene prolapse mesh with an extracellular matrix regenerative graft in a primate sacrocolpopexy model could mitigate the degenerative changes; and (2) determine the impact of the extracellular matrix graft on vagina when implanted alone. STUDY DESIGN A polypropylene-extracellular matrix composite graft (n = 9) and a 6-layered extracellular matrix graft alone (n = 8) were implanted in 17 middle-aged parous rhesus macaques via sacrocolpopexy and compared to historical data obtained from sham (n = 12) and the polypropylene mesh (n = 12) implanted by the same method. Vaginal function was measured in passive (ball-burst test) and active (smooth muscle contractility) mechanical tests. Vaginal histomorphologic/ biochemical assessments included hematoxylin-eosin and trichrome staining, immunofluorescent labeling of α-smooth muscle actin and apoptotic cells, measurement of total collagen, collagen subtypes (ratio III/ I), mature elastin, and sulfated glycosaminoglycans. Statistical analyses included 1-way analysis of variance, Kruskal-Wallis, and appropriate posthoc tests. RESULTS The host inflammatory response in the composite mesh-implanted vagina was reduced compared to that following implantation with the polypropylene mesh alone. The increase in apoptotic cells observed with the polypropylene mesh was blunted in the composite (overall P < .001). Passive mechanical testing showed inferior parameters for both polypropylene mesh alone and the composite compared to sham whereas the contractility and thickness of smooth muscle layer in the composite were improved with a value similar to sham, which was distinct from the decreases observed with polypropylene mesh alone. Biochemically, the composite had similar mature elastin content, sulfated glycosaminoglycan content, and collagen subtype III/I ratio but lower total collagen content when compared to sham (P = .011). Multilayered extracellular matrix graft alone showed overall comparable values to sham in aspects of the biomechanical, histomorphologic, or biochemical end-points of the vagina. The increased collagen subtype ratio III/I with the extracellular matrix graft alone (P = .033 compared to sham) is consistent with an ongoing active remodeling response. CONCLUSION Mesh augmentation with a regenerative extracellular matrix graft attenuated the negative impact of polypropylene mesh on the vagina. Application of the extracellular matrix graft alone had no measurable negative effects suggesting that the benefits of this extra-cellular matrix graft occur when used without a permanent material. Future studies will focus on understanding mechanisms. PMID:27615441

Incisional hernia prevention using a cyanoacrilate-fixed retrofascial mesh.

PubMed

Hoyuela, Carlos; Juvany, Montserrat; Trias, Miquel; Ardid, Jordi; Martrat, Antoni

2018-01-01

The rate of incisional hernia in high-risk patients (obesity, cancer, etc.) is high, even in laparoscopic surgery. The aim of this study is to evaluate the safety of the use of cyanoacrylate fixed prophylactic meshes in the assistance incision in overweight or obese patients undergoing laparoscopic colorectal surgery. A prospective, non-randomized cohort study of patients undergoing elective laparoscopic resection for colorectal cancer between January 2013 and March 2016 was performed. Those with a body mass index greater than 25kg / m 2 were evaluated to implant a prophylactic meshes fixed with cyanoacrylate (Histoacryl®) as reinforcement of the assistance incision. 52 patients were analyzed (mean body mass index: 28.4±2kg / m 2 ). Prophylactic meshes was implanted in 15 patients. The time to put the mesh in place was always less than 5minutes. There was no significant difference in wound infection rate (12% vs. 10%). No mesh had to be explanted. Although the mean follow-up was shorter (14.1±4 vs. 22.3±9 months), there were no incisional hernia in the mesh group. On the other hand, in the non-mesh group, 1 acute evisceration (2.7%) and 4 incisional hernia of the assistance incision were observed (10.8%). There were no significant differences between groups regarding trocar incisional hernia (6.6 vs. 5.4%). The implantation of a reinforcement prophylactic mesh in overweight or obese patients undergoing laparoscopic colorectal surgery is safe and seems to reduce the short-term rate of incisional hernia. Fixation with cyanoacrylate is a rapid method that facilitates the procedure without additional complications. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Immediate Implant-based Prepectoral Breast Reconstruction Using a Vertical Incision

PubMed Central

Lind, Jeffrey G.; Hopkins, Elizabeth G.

2015-01-01

Background: Ideally, breast reconstruction is performed at the time of mastectomy in a single stage with minimal scarring. However, postoperative complications with direct-to-implant subpectoral reconstruction remain significant. These include asymmetry, flap necrosis, animation deformity, and discomfort. We report on a series of patients who have undergone immediate single-stage prepectoral, implant-based breast reconstruction with a smooth, adjustable saline implant covered with mesh/acellular dermal matrix for support using a vertical mastectomy incision. This technique, when combined with an adjustable implant, addresses the complications related to subpectoral implant placement of traditional expanders. Our follow-up time, 4.6 years (55 months), shows a low risk of implant loss and elimination of animation deformity while also providing patients with a safe and aesthetically pleasing result. Methods: All patients who underwent immediate implant-based prepectoral breast reconstruction using a vertical mastectomy incision as a single-staged procedure were included. Charts were reviewed retrospectively. Adjustable smooth round saline implants and mesh/acellular dermal matrix were used for fixation in all cases. Results: Thirty-one patients (62 breasts) underwent single-staged implant-based prepectoral breast reconstruction using a vertical mastectomy incision. Postoperative complications occurred in 9 patients, 6 of which were resolved with postoperative intervention while only 2 cases resulted in implant loss. Conclusions: There can be significant morbidity associated with traditional subpectoral implant-based breast reconstruction. As an alternative, the results of this study show that an immediate single-stage prepectoral breast reconstruction with a smooth saline adjustable implant, using a vertical incision, in conjunction with mesh/matrix support can be performed with excellent aesthetic outcomes and minimal complications. PMID:26180713

Materials characterization and histological analysis of explanted polypropylene, PTFE, and PET hernia meshes from an individual patient

PubMed Central

Wood, A. J.; Cozad, M. J.; Grant, D. A.; Ostdiek, A. M.; Bachman, S. L.

2014-01-01

During its tenure in vivo, synthetic mesh materials are exposed to foreign body responses, which can alter physicochemical properties of the material. Three different synthetic meshes comprised of polypropylene, expanded polytetrafluoroethylene (ePTFE), and polyethylene terephthalate (PET) materials were explanted from a single patient providing an opportunity to compare physicochemical changes between three different mesh materials in the same host. Results from infrared spectroscopy demonstrated significant oxidation in polypropylene mesh while ePTFE and PET showed slight chemical changes that may be caused by adherent scar tissue. Differential scanning calorimetry results showed a significant decrease in the heat of enthalpy and melt temperature in the polypropylene mesh while the ePTFE and PET showed little change. The presence of giant cells and plasma cells surrounding the ePTFE and PET were indicative of an active foreign body response. Scanning electron micrographs and photo micrographs displayed tissue entrapment and distortion of all three mesh materials. PMID:23371769

No increased risk of carcinogenesis with mesh-based hernia repairs.

PubMed

Chughtai, Bilal; Sedrakyan, Art; Thomas, Dominique; Mao, Jialin; Eilber, Karyn S; Clemens, J Quentin; Anger, Jennifer T

2017-12-06

The use of synthetic mesh has been placed under considerable scrutiny. We sought to evaluate whether there is a link between placement of synthetic polypropylene mesh for hernia repair and a subsequent cancer diagnosis. Adult men undergoing mesh-based hernia repair from January 2008-December 2009 in New York State were identified and followed through December 2014. Control cohorts of men undergoing cholecystectomy and total knee replacement were control cohorts. 1894 patients undergoing hernia repair, 912 patients in the cholecystectomy control cohort, and 1099 in the TKA control cohort with a cancer diagnosis. In the matched analyses of mesh-based hernia repair and cholecystectomy patients 6.5% vs. 7.1% developed cancer. In the matched analysis of hernia patients and TKA patients, 9.3% vs. 9.1% developed cancer. No association between mesh-based hernia surgery and increased risk of cancer was found. Mesh-based hernia repair was not associated with an increased risk of subsequent development of cancer in men. Copyright © 2017 Elsevier Inc. All rights reserved.

Fracture load of complete-arch implant-supported prostheses reinforced with nylon-silica mesh: An in vitro study.

PubMed

Gonçalves, Fernanda de Cássia Papaiz; Amaral, Marina; Borges, Alexandre Luiz Souto; Gonçalves, Luiz Fernando Martins; Paes-Junior, Tarcisio José de Arruda

2018-04-01

Complete-arch implant-supported prostheses without a framework have a high risk of failure: a straightforward and inexpensive reinforcement material, such as nylon mesh, could improve their longevity. The purpose of this in vitro study was to evaluate a nylon-silica mesh compound on the fracture strength of acrylic resin and the fracture load of complete-arch implant-supported prostheses. Twenty-four complete mandibular arch implant-supported prostheses were divided into 2 groups according to cantilever length (molar and premolar) and subdivided into another 2 subgroups according to the presence or absence of reinforcing mesh. The specimens were submitted to a maximum load-to-fracture test in a universal testing machine, with a 100-N load cell, a 2 mm/min crosshead speed, and a spherical metal tip diameter of 4 mm at different points (molar and premolar). These were submitted to 1-way analysis of variance for repeated measurement and the post hoc Tukey multiple comparison test (α=.05). The mean maximum load ±standard deviation for the molar group was 393.4 ±95.0 N with reinforcement and 305.4 ±76.3 N without reinforcement (P=.02); and for the premolar group was 1083.3 ±283.7 N with reinforcement and 605.3 ±90.5 N without reinforcement (P=.001). Reinforcement with nylon mesh increased the mean maximum load of implant-supported complete-arch prostheses at both cantilever lengths. The cantilever to the premolar (5 mm) presented the highest maximum load values to fracture. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

[Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

PubMed

Han, Xiao-hui; Zhang, Jia-yu; Cai, Jian-qiu; Shi, Ming-guang

2011-05-10

To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

Lessons and challenges during a 5-year follow-up of 21 Composix Kugel implantations.

PubMed

Wiegering, A; Schlegel, N; Isbert, C; Jurowich, C; Doht, S; Germer, C T; Dietz, U A

2013-08-01

From its introduction in 2000 until its US recall in December 2005, the Composix Kugel mesh was implanted in an estimated 350,000 patients worldwide. In our patients, minor postoperative complications were followed after a few years by more serious problems (persistent abdominal pain, infections, intestinal perforations). In this study, we take stock after a 5-year follow-up and issue a plea for improved product development strategies and the creation of hernia registries. Between 2003 and 2006, we implanted the Bard(®) Composix(®) Kugel(®) mesh in 21 patients (11 men, 10 women, mean age 63.2 ± 13.7 years) with incisional hernias using the open intraperitoneal onlay mesh technique. The mesh is made on one side of ePTFE and on the other of polypropylene and is expanded by a polyethylene (PET) memory recoil ring. The average follow-up was 45.5 months. All patients had at least one risk factor for hernia recurrence. Explanted prostheses were analyzed by scanning electron microscopy (SEM) and subjected to mechanical strength tests. During the postoperative course, six patients suffered a wound healing disorder. Ten patients complained of persistent abdominal wall pain and four experienced recurrence of the hernia. In one patient, the mesh had to be explanted due to chronic infection. In one patient, the PET memory recoil ring broke after 5 years of follow-up with consequent small bowel perforation. The PET memory recoil ring exhibited clear signs of degradation on SEM and unmistakable signs of material fatigue in a materials testing machine. Patients with recalled Composix Kugel meshes face a singular risk for complications that may occur even many years after implantation. The most serious complication is the breakage of its PET memory recoil ring. Since the recall of the Composix Kugel Mesh, we have discontinued its use. It is necessary that future complications are documented in a common post-market surveillance registry. Algorithms need to be developed and promoted to support affected patients and surgeons.

Sexual function in women following transvaginal mesh procedures for the treatment of pelvic organ prolapse.

PubMed

Liang, Ching-Chung; Lo, Tsia-Shu; Tseng, Ling-Hong; Lin, Yi-Hao; Lin, Yu-Jr; Chang, Shuenn-Dhy

2012-10-01

Synthetic mesh kits recently adopted in pelvic reconstructive surgeries have achieved great surgical efficacy, but the effects of transvaginal synthetic mesh procedures on women's sexual function are still controversial. This study was conducted to demonstrate sexual function in women before and after surgery with transvaginal mesh (TVM) repair for pelvic organ prolapse (POP). A total of 93 sexually active women scheduled for correcting POP with synthetic mesh kits were recruited. In addition to urogynecological history, pelvic examination by the Pelvic Organ Prolapse Quantification system, and urodynamic testing, consenting participants were asked to complete the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12) to evaluate sexual function before and after surgery. At the 3-month urodynamic studies, among the 25 patients with coexistent urodynamic stress incontinence (USI) who had undergone a concomitant transobturator suburethral tape procedure (TOT), 1 (4 %) had persistent USI; 8 of 68 (11.8 %) patients with a negative pessary test developed postoperative USI. Six-month prolapse recurrence rates following TVM alone and TVM with concomitant TOT were 9 and 12 %, respectively. The total PISQ-12 score after surgery showed worse results in the TVM alone group but not in the TVM with concomitant TOT group. The individual scores of PISQ-12 after surgery demonstrated prolapse-related items improved in both TVM groups; sexual function worsened in dyspareunia and behavior domains. Our data revealed that transvaginal synthetic mesh procedures for the treatment of POP generated favorable clinical outcomes, but situations might worsen in dyspareunia and behavior domains, thereby invoking a negative emotional reaction during intercourse after surgery.

Microstructure and mechanical properties of open-cellular biomaterials prototypes for total knee replacement implants fabricated by electron beam melting.

PubMed

Murr, L E; Amato, K N; Li, S J; Tian, Y X; Cheng, X Y; Gaytan, S M; Martinez, E; Shindo, P W; Medina, F; Wicker, R B

2011-10-01

Total knee replacement implants consisting of a Co-29Cr-6Mo alloy femoral component and a Ti-6Al-4V tibial component are the basis for the additive manufacturing of novel solid, mesh, and foam monoliths using electron beam melting (EBM). Ti-6Al-4V solid prototype microstructures were primarily α-phase acicular platelets while the mesh and foam structures were characterized by α(')-martensite with some residual α. The Co-29Cr-6Mo containing 0.22% C formed columnar (directional) Cr(23)C(6) carbides spaced ~2 μm in the build direction, while HIP-annealed Co-Cr alloy exhibited an intrinsic stacking fault microstructure. A log-log plot of relative stiffness versus relative density for Ti-6Al-4V and Co-29Cr-6Mo open-cellular mesh and foams resulted in a fitted line with a nearly ideal slope, n = 2.1. A stress shielding design graph constructed from these data permitted mesh and foam implant prototypes to be fabricated for compatible bone stiffness. Copyright © 2011 Elsevier Ltd. All rights reserved.

Morphologic study of three collagen materials for body wall repair.

PubMed

Soiderer, Emily E; Lantz, Gary C; Kazacos, Evelyn A; Hodde, Jason P; Wiegand, Ryan E

2004-05-15

The search for ideal prostheses for body wall repair continues. Synthetic materials such as polypropylene mesh (PPM) are associated with healing complications. A porcine-derived collagen-based material (CBM), small intestinal submucosa (SIS), has been studied for body wall repair. Renal capsule matrix (RCM) and urinary bladder submucosa (UBS) are CBMs not previously evaluated in this application. This is the first implant study using RCM. Full-thickness muscle/fascia ventral abdominal wall defects were repaired with SIS, RCM, UBS, and PPM in rats with omentum and omentectomy. A random complete block design was used to allot implant type to each of 96 rats. Healing was evaluated at 4 and 8 weeks. Adhesion tenacity and surface area were scored. Implant site dimensions were measured at implantation and necropsy. Inflammation, vascularization, and fibrosis were histopathologically scored. Data were compared by analysis of variance (P < 0.05). PPM produced a granulomatous foreign body response in contrast to the organized healing of CBM implants. CBM mean scores were lower than PPM scores for adhesion tenacity, surface area, and inflammation at each follow-up time for rats with omentums (P < 0.02). The CBMs had less tenacity and inflammation than PPM at each follow-up time in omentectomy groups (P < 0.008). Wound contraction was greater for PPM (P < 0.0001) for all rats. RCM and UBS were similar to SIS invoking reduced inflammation, adhesion, and contraction compared to PPM. The fibrotic response to PPM was unique and more intense compared to CBMs. These CBM implants appear morphologically acceptable and warrant continued investigation.

Immediate Titanium Mesh Implantation for Patients with Postcraniotomy Neurosurgical Site Infections: Safe and Aesthetic Alternative Procedure?

PubMed

Ehrlich, Gregory; Kindling, Stefanie; Wenz, Holger; Hänggi, Daniel; Schulte, Dirk Michael; Schmiedek, Peter; Seiz-Rosenhagen, Marcel

2017-03-01

Surgical site infection (SSI) is one of the main complications after craniotomy. The incidence is up to 11% in the literature. The established procedure is debridement, removal of the bone flap, and delayed cranioplasty. Delayed cranioplasty has several disadvantages. A promising approach is the immediate titanium mesh implantation at the time of wound revision. We report our experience with this technique regarding outcome measured by reinfection rates and patient satisfaction. Patients treated in our department from January 2013 to October 2014 with SSI after craniotomy for brain tumor, trauma, or vascular pathologies were prospectively collected. In all these patients, immediate titanium mesh implantation after bone flap removal was performed. Primary outcome parameters were the reinfection rate and patient satisfaction via self-designed questionnaires in a follow-up period >3 months. Twenty-four patients were included within the study period. Main risk factors causing SSI were previous steroid medication (62.5%), cranial radiation therapy (42%), cerebrospinal fluid fistula after initial surgery (12.5%), and diabetes mellitus (25%). The follow-up was >3 months after titanium mesh cranioplasty (mean 4.6 months; range 3-6 months). No recurrent infection was detected in the study group. In 2 cases, reoperation was necessary. The returning questionnaires showed a high satisfaction rate with the cosmetic result. Our small series seems to confirm that immediate titanium mesh implantation for patients with postcraniotomy SSI is a cost-effective, safe, and cosmetically suitable alternative to delayed cranioplasty in selected patients without hydrocephalus or persistent cerebrospinal fluid fistula. Copyright © 2016 Elsevier Inc. All rights reserved.

Trabecular bone strains around a dental implant and associated micromotions--a micro-CT-based three-dimensional finite element study.

PubMed

Limbert, Georges; van Lierde, Carl; Muraru, O Luiza; Walboomers, X Frank; Frank, Milan; Hansson, Stig; Middleton, John; Jaecques, Siegfried

2010-05-07

The first objective of this computational study was to assess the strain magnitude and distribution within the three-dimensional (3D) trabecular bone structure around an osseointegrated dental implant loaded axially. The second objective was to investigate the relative micromotions between the implant and the surrounding bone. The work hypothesis adopted was that these virtual measurements would be a useful indicator of bone adaptation (resorption, homeostasis, formation). In order to reach these objectives, a microCT-based finite element model of an oral implant implanted into a Berkshire pig mandible was developed along with a robust software methodology. The finite element mesh of the 3D trabecular bone architecture was generated from the segmentation of microCT scans. The implant was meshed independently from its CAD file obtained from the manufacturer. The meshes of the implant and the bone sample were registered together in an integrated software environment. A series of non-linear contact finite element (FE) analyses considering an axial load applied to the top of the implant in combination with three sets of mechanical properties for the trabecular bone tissue was devised. Complex strain distribution patterns are reported and discussed. It was found that considering the Young's modulus of the trabecular bone tissue to be 5, 10 and 15GPa resulted in maximum peri-implant bone microstrains of about 3000, 2100 and 1400. These results indicate that, for the three sets of mechanical properties considered, the magnitude of maximum strain lies within an homeostatic range known to be sufficient to maintain/form bone. The corresponding micro-motions of the implant with respect to the bone microstructure were shown to be sufficiently low to prevent fibrous tissue formation and to favour long-term osseointegration. Copyright 2010 Elsevier Ltd. All rights reserved.

Surface orientation effects on bending properties of surgical mesh are independent of tensile properties.

PubMed

Simon, David D; Andrews, Sharon M; Robinson-Zeigler, Rebecca; Valdes, Thelma; Woods, Terry O

2018-02-01

Current mechanical testing of surgical mesh focuses primarily on tensile properties even though implanted devices are not subjected to pure tensile loads. Our objective was to determine the flexural (bending) properties of surgical mesh and determine if they correlate with mesh tensile properties. The flexural rigidity values of 11 different surgical mesh designs were determined along three textile directions (machine, cross-machine, and 45° to machine; n = 5 for each) using ASTM D1388-14 while tracking surface orientation. Tensile testing was also performed on the same specimens using ASTM D882-12. Linear regressions were performed to compare mesh flexural rigidity to mesh thickness, areal mass density, filament diameter, ultimate tensile strength, and maximum extension. Of 33 mesh specimen groups, 30 had significant differences in flexural rigidity values when comparing surface orientations (top and bottom). Flexural rigidity and mesh tensile properties also varied with textile direction (machine and cross-machine). There was no strong correlation between the flexural and tensile properties, with mesh thickness having the best overall correlation with flexural rigidity. Currently, surface orientation is not indicated on marketed surgical mesh, and a single mesh may behave differently depending on the direction of loading. The lack of correlation between flexural stiffness and tensile properties indicates the need to examine mesh bending stiffness to provide a more comprehensive understanding of surgical mesh mechanical behaviors. Further investigation is needed to determine if these flexural properties result in the surgical mesh behaving mechanically different depending on implantation direction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 854-862, 2018. © 2017 Wiley Periodicals, Inc.

Update on Bioactive Prosthetic Material for the Treatment of Hernias.

PubMed

Edelman, David S; Hodde, Jason P

2011-12-01

The use of mesh in the repair of hernias is commonplace. Synthetic mesh, like polypropylene, has been the workhorse for hernia repairs since the 1980s. Surgisis® mesh (Cook Surgical, Bloomington, IN), a biologic hernia graft material composed of purified porcine small intestinal submucosa (SIS), was first introduced to the United States in 1998 as an alternative to synthetic mesh materials. This mesh, composed of extracellular matrix collagen, fibronectin and associated glycosaminoglycans and growth factors, has been extensively investigated in animal models and used clinically in many types of surgical procedures. SIS acts as a scaffold for natural growth and strength. We reported our initial results in this publication in July 2006. Since then, there have been many more reports and numerous other bioactive prosthetic materials (BPMs) released. The object of this article is to briefly review some of the current literature on the use of BPM for inguinal hernias, sports hernias, and umbilical hernias.

Incidence of Extrusion Following Type I Polypropylene Mesh “Kit” Repairs in the Correction of Pelvic Organ Prolapse

PubMed Central

Lukban, James C.; Beyer, Roger D.; Moore, Robert D.

2012-01-01

Introduction and Hypothesis. We sought to determine the mesh extrusion (vaginal exposure) rates and subject outcomes following IntePro (Type I polypropylene) mesh “kit” repairs for vaginal prolapse. Methods. Data were pooled from two prospective multicenter studies evaluating the safety and efficacy of the Perigee and Apogee (American Medical Systems, Minnetonka, Minn, USA) to treat anterior and posterior/apical prolapses, respectively. Extrusions involving the anterior compartment (AC) or posterior compartment/apex (PC/A) were recorded. Results. Two hundred sixty women underwent mesh placement, with a total of 368 mesh units inserted (173 in the AC and 195 in the PC/A). Extrusions were noted in 13 (7.5%) of AC implants and 27 (13.8%) of PC/A implants through 12 months. No difference was seen between those with and without extrusion in regard to anatomic cure, postoperative painor quality of life at 1 year. Conclusions. Extrusion had no apparent effect on short-term outcomes. Given the unknown long-term sequellae of vaginal mesh exposure, a thorough assessment of risks and benefits of transvaginal mesh placement should be considered at the time of preoperative planning. PMID:22190952

Does PRP enhance bone integration with grafts, graft substitutes, or implants? A systematic review

PubMed Central

2013-01-01

Background Several bone implants are applied in clinical practice, but none meets the requirements of an ideal implant. Platelet-rich plasma (PRP) is an easy and inexpensive way to obtain growth factors in physiologic proportions that might favour the regenerative process. The aim of this review is to analyse clinical studies in order to investigate the role of PRP in favouring bone integration of graft, graft substitutes, or implants, and to identify the materials for which the additional use of PRP might be associated with superior osseo- and soft tissues integration. Methods A search on PubMed database was performed considering the literature from 2000 to 2012, using the following string: ("Bone Substitutes"[Mesh] OR "Bone Transplantation"[Mesh] OR "Bone Regeneration"[Mesh] OR "Osseointegration"[Mesh]) AND ("Blood Platelets"[Mesh] OR "Platelet-Rich Plasma"[Mesh]). After abstracts screening, the full-texts of selected papers were analyzed and the papers found from the reference lists were also considered. The search focused on clinical applications documented in studies in the English language: levels of evidence included in the literature analysis were I, II and III. Results Literature analysis showed 83 papers that fulfilled the inclusion criteria: 26 randomized controlled trials (RCT), 14 comparative studies, 29 case series, and 14 case reports. Several implant materials were identified: 24 papers on autologous bone, 6 on freeze-dried bone allograft (FDBA), 16 on bovine porous bone mineral (BPBM), 9 on β-tricalcium phosphate (β-TCP), 4 on hydroxyapatite (HA), 2 on titanium (Ti), 1 on natural coral, 1 on collagen sponge, 1 on medical-grade calcium sulphate hemihydrate (MGCSH), 1 on bioactive glass (BG) and 18 on a combination of biomaterials. Only 4 papers were related to the orthopaedic field, whereas the majority belonged to clinical applications in oral/maxillofacial surgery. Conclusions The systematic research showed a growing interest in this approach for bone implant integration, with an increasing number of studies published over time. However, knowledge on this topic is still preliminary, with the presence mainly of low quality studies. Many aspects still have to be understood, such as the biomaterials that can benefit most from PRP and the best protocol for PRP both for production and application. PMID:24261343

Biaxial analysis of synthetic scaffolds for hernia repair demonstrates variability in mechanical anisotropy, non-linearity and hysteresis.

PubMed

Deeken, Corey R; Thompson, Dominic M; Castile, Ryan M; Lake, Spencer P

2014-10-01

Over the past 60 years, the soft tissue repair market has grown to include over 50 types of hernia repair materials. Surgeons typically implant these materials in the orientation that provides maximum overlap of the mesh over the defect, with little regard for mechanical properties of the mesh material. If the characteristics of the meshes were better understood, an appropriate material could be identified for each patient, and meshes could be placed to optimize integration with neighboring tissue and avoid the mechanical mis-match that can lead to impaired graft fixation. The purpose of this study was to fully characterize and compare the mechanical properties of thirteen types of hernia repair materials via planar biaxial tensile testing. Equibiaxial (i.e., equal simultaneous loading in both directions) and strip biaxial (i.e., loading in one direction with the other direction held fixed) tests were utilized as physiologically relevant loading regimes. After applying a 0.1N pre-load on each arm, samples were subjected to equibiaxial cyclic loading using a triangular waveform to 2.5mm displacement on each arm at 0.1Hz for 10 cycles. Samples were then subjected to two strip biaxial tests (using the same cyclic loading protocol), where extension was applied along a single axis with the other axis held fixed. The thirteen evaluated mesh types exhibited a wide range of mechanical properties. Some were nearly isotropic (C-QUR™, DUALMESH(®), PHYSIOMESH™, and PROCEED(®)), while others were highly anisotropic (Ventralight™ ST, Bard™ Mesh, and Bard™ Soft Mesh). Some displayed nearly linear behavior (Bard™ Mesh), while others were non-linear with a long toe region followed by a sharp rise in tension (INFINIT(®)). These materials are currently utilized in clinical settings as if they are uniform and interchangeable, and clearly this is not the case. The mechanical properties most advantageous for successful hernia repairs are currently only vaguely described in the clinical literature. The characteristics of the human abdominal wall must be extensively characterized to provide a thorough understanding of the tissue being reinforced/replaced by these meshes. A better understanding of these mechanical differences would enable matching of patient characteristics to a specific mesh with the properties best suited to that particular repair. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fixation free femoral hernia repair with a 3D dynamic responsive implant. A case series report.

PubMed

Amato, G; Romano, G; Agrusa, A; Gordini, L; Gulotta, E; Erdas, E; Calò, P G

2018-04-23

To date, no gold standard for the surgical treatment of femoral hernia exists. Pure tissue repair as well as mesh/plug implantation, open or laparoscopic, are the most performed methods. Nevertheless, all these techniques need sutures or mesh fixation. This implies the risk of damaging sensitive structures of the femoral area, along with complications related to tissue tear and postoperative discomfort consequent to poor quality mesh incorporation. The present retrospective multicenter case series highlights the results of femoral hernia repair procedures performed with a 3D dynamic responsive implant in a cohort of 32 patients during a mean follow up of 27 months. Aiming to simplify the surgical procedure and reduce complications, a 3D dynamic responsive implant was delivered for femoral hernia repair, in a patient cohort. After returning the hernia sack to the abdominal cavity, the implant was simply delivered into the hernia defect where it remained, thanks to its inherent centrifugal expansion, obliterating the hernia opening without need of fixation. Postoperative pain assessment was determined using the VAS score system. The use of the 3D prosthetic device allowed for easier and faster surgical repair in a fixation free fashion. None of the typical fixation related complications occurred in the examined patients. Postoperative pain assessment with VAS score showed a very low level of pain, allowing the return of patients to normal activities in extremely reduced times. In the late postoperative period, no discomfort or chronic pain was reported. Femoral hernia repair with the 3D dynamic revealed a quick and safe placement procedure. The reduced pain intensity, as well as the absence of adverse events consequent to sutures or mesh fixation, seems to be a significant benefit of the motile compliance of the device. Furthermore, this 3D prosthesis has already proven to induce an enhanced probiotic response showing ingrowth in the implant of the typical tissue components of the abdominal wall, instead of the low quality tissue ingrowth typical in conventional meshes and plugs. The highlighted features seem to represent a more physiologic and updated repair concept of femoral protrusions. Copyright © 2018 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

Imaging, Virtual Planning, Design, and Production of Patient-Specific Implants and Clinical Validation in Craniomaxillofacial Surgery

PubMed Central

Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-M

2012-01-01

The purpose of this article was to describe the workflow from imaging, via virtual design, to manufacturing of patient-specific titanium reconstruction plates, cutting guide and mesh, and its utility in connection with surgical treatment of acquired bone defects in the mandible using additive manufacturing by electron beam melting (EBM). Based on computed tomography scans, polygon skulls were created. Following that virtual treatment plans entailing free microvascular transfer of fibula flaps using patient-specific reconstruction plates, mesh, and cutting guides were designed. The design was based on the specification of a Compact UniLOCK 2.4 Large (Synthes®, Switzerland). The obtained polygon plates were bent virtually round the reconstructed mandibles. Next, the resections of the mandibles were planned virtually. A cutting guide was outlined to facilitate resection, as well as plates and titanium mesh for insertion of bone or bone substitutes. Polygon plates and meshes were converted to stereolithography format and used in the software Magics for preparation of input files for the successive step, additive manufacturing. EBM was used to manufacture the customized implants in a biocompatible titanium grade, Ti6Al4V ELI. The implants and the cutting guide were cleaned and sterilized, then transferred to the operating theater, and applied during surgery. Commercially available software programs are sufficient in order to virtually plan for production of patient-specific implants. Furthermore, EBM-produced implants are fully usable under clinical conditions in reconstruction of acquired defects in the mandible. A good compliance between the treatment plan and the fit was demonstrated during operation. Within the constraints of this article, the authors describe a workflow for production of patient-specific implants, using EBM manufacturing. Titanium cutting guides, reconstruction plates for fixation of microvascular transfer of osteomyocutaneous bone grafts, and mesh to replace resected bone that can function as a carrier for bone or bone substitutes were designed and tested during reconstructive maxillofacial surgery. A clinically fit, well within the requirements for what is needed and obtained using traditional free hand bending of commercially available devices, or even higher precision, was demonstrated in ablative surgery in four patients. PMID:23997858

Imaging, virtual planning, design, and production of patient-specific implants and clinical validation in craniomaxillofacial surgery.

PubMed

Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-M

2012-09-01

The purpose of this article was to describe the workflow from imaging, via virtual design, to manufacturing of patient-specific titanium reconstruction plates, cutting guide and mesh, and its utility in connection with surgical treatment of acquired bone defects in the mandible using additive manufacturing by electron beam melting (EBM). Based on computed tomography scans, polygon skulls were created. Following that virtual treatment plans entailing free microvascular transfer of fibula flaps using patient-specific reconstruction plates, mesh, and cutting guides were designed. The design was based on the specification of a Compact UniLOCK 2.4 Large (Synthes(®), Switzerland). The obtained polygon plates were bent virtually round the reconstructed mandibles. Next, the resections of the mandibles were planned virtually. A cutting guide was outlined to facilitate resection, as well as plates and titanium mesh for insertion of bone or bone substitutes. Polygon plates and meshes were converted to stereolithography format and used in the software Magics for preparation of input files for the successive step, additive manufacturing. EBM was used to manufacture the customized implants in a biocompatible titanium grade, Ti6Al4V ELI. The implants and the cutting guide were cleaned and sterilized, then transferred to the operating theater, and applied during surgery. Commercially available software programs are sufficient in order to virtually plan for production of patient-specific implants. Furthermore, EBM-produced implants are fully usable under clinical conditions in reconstruction of acquired defects in the mandible. A good compliance between the treatment plan and the fit was demonstrated during operation. Within the constraints of this article, the authors describe a workflow for production of patient-specific implants, using EBM manufacturing. Titanium cutting guides, reconstruction plates for fixation of microvascular transfer of osteomyocutaneous bone grafts, and mesh to replace resected bone that can function as a carrier for bone or bone substitutes were designed and tested during reconstructive maxillofacial surgery. A clinically fit, well within the requirements for what is needed and obtained using traditional free hand bending of commercially available devices, or even higher precision, was demonstrated in ablative surgery in four patients.

Evaluation of current synthetic mesh materials in pelvic organ prolapse repair.

PubMed

Kanagarajah, Prashanth; Ayyathurai, Rajinikanth; Gomez, Christopher

2012-06-01

With increasing use of synthetic material in pelvic organ prolapse repair, the reporting and incidence of associated complications also have increased. The role of synthetic mesh in pelvic organ prolapse repair remains controversial and it is a therapeutic dilemma whether to continue its use in patients with poor native tissues, despite the recent public safety notification provided by the U.S. Food and Drug Administration. In this article, we review the biomaterials used in pelvic organ prolapse repair and discuss the outcomes and associated complications, paying emphasis to the benefits and the risks.

Mesh for prolapse surgery: Why the fuss?

PubMed

Rajshekhar, Smita; Mukhopadhyay, Sambit; Klinge, Uwe

2015-06-01

Pelvic organ prolapse is a common gynaecological problem. Surgical techniques to repair prolapse have been constantly evolving to reduce the recurrence of prolapse and need for reoperation. Grafts made of synthetic and biological materials became popular in the last decade as they were intended to provide extra support to native tissue repairs. However, serious complications related to use of synthetic meshes have been reported and there is increasing medico-legal concern about mesh use in prolapse surgery. Some mesh products already have been withdrawn from the market and the FDA has introduced stricter surveillance of new and existing products. Large randomized studies comparing mesh with non-mesh procedures are lacking which creates uncertainty for the surgeon and their patients.The small cohorts of the RCTs available with short follow-up periods just allow the conclusion that the mesh repair can be helpful in the short to medium term but unfortunately are not able to prove safety for all patients. In particular, current clinical reports cannot define for which indication what material may be superior compared to non-mesh repair.Quality control through long-term individual and national mesh registries is needed to keep a record of all surgeons using mesh and all devices being used, monitoring their effectiveness and safety data. Meshes with better biocompatibility designed specifically for use in vaginal surgery may provide superior clinical results, where the reduction of complications may allow a wider range of indications. © The Author(s) 2015.

[Implants for genital prolapse : Contra mesh surgery].

PubMed

Hampel, C

2017-12-01

Alloplastic transvaginal meshes have become very popular in the surgery of pelvic organ prolapse (POP) as did alloplastic suburethral slings in female stress incontinence surgery, but without adequate supporting data. The simplicity of the mesh procedure facilitates its propagation with acceptance of higher revision and complication rates. Since attending physicians do more and more prolapse surgeries without practicing or teaching alternative techniques, expertise in these alternatives, which might be very useful in cases of recurrence, persistence or complications, is permanently lost. It is doubtful that proper and detailed information about alternatives, risks, and benefits of transvaginal alloplastic meshes is provided to every single prolapse patient according to the recommendations of the German POP guidelines, since the number of implanted meshes exceeds the number of properly indicated mesh candidates by far. Although there is no dissent internationally about the available mesh data, thousands of lawsuits in the USA, insolvency of companies due to claims for compensation and unambiguous warnings from foreign urological societies leave German urogynecologists still unimpressed. The existing literature in pelvic organ prolapse exclusively focusses on POP stage and improvement of that stage with surgical therapy. Instead, typical prolapse symptoms should trigger therapy and improvement of these symptoms should be the utmost treatment goal. It is strongly recommended for liability reasons to obtain specific written informed consent.

Mechanical verification of soft-tissue attachment on bioactive glasses and titanium implants.

PubMed

Zhao, Desheng; Moritz, Niko; Vedel, Erik; Hupa, Leena; Aro, Hannu T

2008-07-01

Soft-tissue attachment is a desired feature of many clinical biomaterials. The aim of the current study was to design a suitable experimental method for tensile testing of implant incorporation with soft-tissues. Conical implants were made of three compositions of bioactive glass (SiO(2)-P(2)O(5)-B(2)O(3)-Na(2)O-K(2)O-CaO-MgO) or titanium fiber mesh (porosity 84.7%). The implants were surgically inserted into the dorsal subcutaneous soft-tissue or back muscles in the rat. Soft-tissue attachment was evaluated by pull-out testing using a custom-made jig 8 weeks after implantation. Titanium fiber mesh implants had developed a relatively high pull-out force in subcutaneous tissue (12.33+/-5.29 N, mean+/-SD) and also measurable attachment with muscle tissue (2.46+/-1.33 N). The bioactive glass implants failed to show mechanically relevant soft-tissue bonding. The experimental set-up of mechanical testing seems to be feasible for verification studies of soft-tissue attachment. The inexpensive small animal model is beneficial for large-scale in vivo screening of new biomaterials.

Non-cross-linked porcine acellular dermal matrices for abdominal wall reconstruction.

PubMed

Burns, Nadja K; Jaffari, Mona V; Rios, Carmen N; Mathur, Anshu B; Butler, Charles E

2010-01-01

Non-cross-linked porcine acellular dermal matrices have been used clinically for abdominal wall repair; however, their biologic and mechanical properties and propensity to form visceral adhesions have not been studied. The authors hypothesized that their use would result in fewer, weaker visceral adhesions than polypropylene mesh when used to repair ventral hernias and form a strong interface with the surrounding musculofascia. Thirty-four guinea pigs underwent inlay repair of surgically created ventral hernias using polypropylene mesh, porcine acellular dermal matrix, or a composite of the two. The animals were killed at 4 weeks, and the adhesion tenacity grade and surface area of the repair site involved by adhesions were measured. Sections of the repair sites, including the implant-musculofascia interface, underwent histologic analysis and uniaxial mechanical testing. The incidence of bowel adhesions to the repair site was significantly lower with the dermal matrix (8 percent, p < 0.01) and the matrix/mesh combination (0 percent, p < 0.001) than with polypropylene mesh alone (70 percent). The repairs made with the matrix or the matrix/mesh combination, compared with the polypropylene mesh repairs, had significantly lower mean adhesion surface areas [12.8 percent (p < 0.001), 9.2 percent (p < 0.001), and 79.9 percent] and grades [0.6 (p < 0.001), 0.6 (p < 0.001), and 2.9]. The dermal matrix underwent robust cellular and vascular infiltration. The ultimate tensile strength at the implant-musculofascia interface was similar in all groups. Porcine acellular dermal matrix becomes incorporated into the host tissue and causes fewer adhesions to repair sites than does polypropylene mesh, with similar implant-musculofascia interface strength. It also inhibits adhesions to adjacent dermal matrix in the combination repairs. It has distinct advantages over polypropylene mesh for complex abdominal wall repairs, particularly when material placement directly over bowel is unavoidable.

Macrophage polarization in response to ECM coated polypropylene mesh

PubMed Central

Wolf, MT; Dearth, CL; Ranallo, CA; LoPresti, S; Carey, LE; Daly, KA; Brown, BN; Badylak, SF

2015-01-01

The host response to implanted biomaterials is a highly regulated process that influences device functionality and clinical outcome. Non-degradable biomaterials, such as knitted polypropylene mesh, frequently elicit a chronic foreign body reaction with resultant fibrosis. Previous studies have shown that an extracellular matrix (ECM) hydrogel coating of polypropylene mesh reduces the intensity of the foreign body reaction, though the mode of action is unknown. Macrophage participation plays a key role in the development of the foreign body reaction to biomaterials, and therefore the present study investigated macrophage polarization following mesh implantation. Spatiotemporal analysis of macrophage polarization was conducted in response to uncoated polypropylene mesh and mesh coated with hydrated and dry forms of ECM hydrogels derived from either dermis or urinary bladder. Pro-inflammatory M1 macrophages (CD86+/CD68+), alternatively activated M2 macrophages (CD206+/CD68+), and foreign body giant cells were quantified between 3-35 days. Uncoated polypropylene mesh elicited a dominant M1 response at the mesh fiber surface, which was decreased by each ECM coating type beginning at 7 days. The diminished M1 response was accompanied by a reduction in the number of foreign body giant cells at 14 and 35 days, though there was a minimal effect upon the number of M2 macrophages at any time. These results show that ECM coatings attenuate the M1 macrophage response and increase the M2/M1 ratio to polypropylene mesh in vivo. PMID:24856104

Polypropylene Surgical Mesh Coated with Extracellular Matrix Mitigates the Host Foreign Body Response

PubMed Central

Wolf, Matthew T.; Carruthers, Christopher A.; Dearth, Christopher L.; Crapo, Peter M.; Huber, Alexander; Burnsed, Olivia A.; Londono, Ricardo; Johnson, Scott A.; Daly, Kerry A.; Stahl, Elizabeth C.; Freund, John M.; Medberry, Christopher J.; Carey, Lisa E.; Nieponice, Alejandro; Amoroso, Nicholas J.; Badylak, Stephen F.

2013-01-01

Surgical mesh devices composed of synthetic materials are commonly used for ventral hernia repair. These materials provide robust mechanical strength and are quickly incorporated into host tissue; factors which contribute to reduced hernia recurrence rates. However, such mesh devices cause a foreign body response with the associated complications of fibrosis and patient discomfort. In contrast, surgical mesh devices composed of naturally occurring extracellular matrix (ECM) are associated with constructive tissue remodeling, but lack the mechanical strength of synthetic materials. A method for applying a porcine dermal ECM hydrogel coating to a polypropylene mesh is described herein with the associated effects upon the host tissue response and biaxial mechanical behavior. Uncoated and ECM coated heavy-weight BARD™ Mesh were compared to the light-weight ULTRAPRO™ and BARD™ Soft Mesh devices in a rat partial thickness abdominal defect overlay model. The ECM coated mesh attenuated the pro-inflammatory response compared to all other devices, with a reduced cell accumulation and fewer foreign body giant cells. The ECM coating degraded by 35 days, and was replaced with loose connective tissue compared to the dense collagenous tissue associated with the uncoated polypropylene mesh device. Biaxial mechanical characterization showed that all of the mesh devices were of similar isotropic stiffness. Upon explantation, the light-weight mesh devices were more compliant than the coated or uncoated heavy-weight devices. The present study shows that an ECM coating alters the default host response to a polypropylene mesh, but not the mechanical properties in an acute in vivo abdominal repair model. PMID:23873846

Evidence-based outcomes for mesh-based surgery for pelvic organ prolapse.

PubMed

Mettu, Jayadev R; Colaco, Marc; Badlani, Gopal H

2014-07-01

In light of all the recent controversy regarding the use of synthetic mesh for pelvic organ prolapse, we did a retrospective review of the evidence-based outcomes and complications for its use. A total of 18 of the most recent studies in the last 5 years were selected. Studies selected were prospective randomized or quasi-randomized controlled trials that included surgical operations for pelvic organ prolapse for this review. Additionally, Cochrane review and meta-analysis of outcomes and complication were also analyzed. In terms of outcomes, the definition of successful surgery is currently being debated. Synthetic mesh provides superior anatomical and subjective cure rates compared with native tissue repair. Success rates varied greatly depending on the nature of prolapse and surgical approach. Furthermore, recurrence rates for mesh-based surgery are significantly lower than that for native tissue repair. The main unique complication of mesh is exposure and was reported in a mean of 11.4% of patients, with 6.8% of patients requiring surgical partial excision of mesh. Mesh significantly improves anatomical outcomes with sacrocolpopexy and vaginal repair. Mesh does create the unique complication which can be reduced with training and proper patient selection. Further development of better materials is vital rather than reverting to tissue-based repair. Ultimately, the decision to use mesh should be based upon a patient's personal goals and preferences after an informed conversation with her physician.

Laparoscopy-like operative vaginoscopy: a new approach to manage mesh erosions.

PubMed

Billone, Valentina; Amorim-Costa, Célia; Campos, Sara; Rabischong, Benoĭt; Bourdel, Nicolas; Canis, Michel; Botchorishvili, Revaz

2015-01-01

Mesh erosion through the vagina is the most common complication of synthetic mesh used for pelvic organ prolapse repair. However, conventional transvaginal mesh excision has many technical limitations. We aimed at creating and describing a new surgical technique for transvaginal removal of exposed mesh that would enable better exposition and access, thus facilitating optimal treatment. A step-by-step video showing the technique. A university tertiary care hospital. Five patients previously submitted to pelvic organ prolapse repair using synthetic mesh, presenting mesh erosion through the vagina. Mesh excision using a laparoscopy-like operative vaginoscopy in which standard laparoscopic instruments are used through a single-incision laparoscopic surgery port device placed in the vagina. In all cases, a very good exposure of the mesh was achieved, a minimal tissue traction was required, and the procedures were performed in a very ergonomic way. All the patients were discharged on the same day of the surgery and had a painless postoperative course. So far, there have been no cases of relapse. This seems to be a simple, cheap, and valuable minimally invasive technique with many advantages in comparison with the conventional approach. More cases and time are necessary to access its long-term efficacy. It may possibly be used for the management of other conditions. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh.

PubMed

Matthews, Brent D; Pratt, Broc L; Pollinger, Harrison S; Backus, Charles L; Kercher, Kent W; Sing, R F; Heniford, B Todd

2003-10-01

The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.

iNOS Activity Modulates Inflammation, Angiogenesis, and Tissue Fibrosis in Polyether-Polyurethane Synthetic Implants

PubMed Central

Cassini-Vieira, Puebla; Araújo, Fernanda Assis; da Costa Dias, Filipi Leles; Russo, Remo Castro; Andrade, Silvia Passos; Teixeira, Mauro Martins; Barcelos, Luciola Silva

2015-01-01

There is considerable interest in implantation techniques and scaffolds for tissue engineering and, for safety and biocompatibility reasons, inflammation, angiogenesis, and fibrosis need to be determined. The contribution of inducible nitric oxide synthase (iNOS) in the regulation of the foreign body reaction induced by subcutaneous implantation of a synthetic matrix was never investigated. Here, we examined the role of iNOS in angiogenesis, inflammation, and collagen deposition induced by polyether-polyurethane synthetic implants, using mice with targeted disruption of the iNOS gene (iNOS−/−) and wild-type (WT) mice. The hemoglobin content and number of vessels were decreased in the implants of iNOS−/− mice compared to WT mice 14 days after implantation. VEGF levels were also reduced in the implants of iNOS−/− mice. In contrast, the iNOS−/− implants exhibited an increased neutrophil and macrophage infiltration. However, no alterations were observed in levels of CXCL1 and CCL2, chemokines related to neutrophil and macrophage migration, respectively. Furthermore, the implants of iNOS−/− mice showed boosted collagen deposition. These data suggest that iNOS activity controls inflammation, angiogenesis, and fibrogenesis in polyether-polyurethane synthetic implants and that lack of iNOS expression increases foreign body reaction to implants in mice. PMID:26106257

iNOS Activity Modulates Inflammation, Angiogenesis, and Tissue Fibrosis in Polyether-Polyurethane Synthetic Implants.

PubMed

Cassini-Vieira, Puebla; Araújo, Fernanda Assis; da Costa Dias, Filipi Leles; Russo, Remo Castro; Andrade, Silvia Passos; Teixeira, Mauro Martins; Barcelos, Luciola Silva

2015-01-01

There is considerable interest in implantation techniques and scaffolds for tissue engineering and, for safety and biocompatibility reasons, inflammation, angiogenesis, and fibrosis need to be determined. The contribution of inducible nitric oxide synthase (iNOS) in the regulation of the foreign body reaction induced by subcutaneous implantation of a synthetic matrix was never investigated. Here, we examined the role of iNOS in angiogenesis, inflammation, and collagen deposition induced by polyether-polyurethane synthetic implants, using mice with targeted disruption of the iNOS gene (iNOS(-/-)) and wild-type (WT) mice. The hemoglobin content and number of vessels were decreased in the implants of iNOS(-/-) mice compared to WT mice 14 days after implantation. VEGF levels were also reduced in the implants of iNOS(-/-) mice. In contrast, the iNOS(-/-) implants exhibited an increased neutrophil and macrophage infiltration. However, no alterations were observed in levels of CXCL1 and CCL2, chemokines related to neutrophil and macrophage migration, respectively. Furthermore, the implants of iNOS(-/-) mice showed boosted collagen deposition. These data suggest that iNOS activity controls inflammation, angiogenesis, and fibrogenesis in polyether-polyurethane synthetic implants and that lack of iNOS expression increases foreign body reaction to implants in mice.

Highly flexible nitinol mesh to encase aortocoronary saphenous vein grafts: first clinical experiences and angiographic results nine months postoperatively.

PubMed

Schoettler, Jan; Jussli-Melchers, Jill; Grothusen, Christina; Stracke, Lars; Schoeneich, Felix; Stohn, Simon; Hoffmann, Grischa; Cremer, Jochen

2011-10-01

Saphenous vein graft patency is frequently limited by degeneration. Experimental studies have indicated that rigid external support of venous grafts by a flexible, tubular nitinol mesh may improve graft patency. The study presented was part of a prospective, randomized, multicenter first-in-man trial investigating the safety and effectiveness of nitinol-supported venous grafts in coronary artery bypass graft (CABG) surgery. From our clinic, 25 subjects with multivessel coronary artery disease requiring saphenous vein graft CABG of the right coronary artery (RCA) and the circumflex artery were entered into the trial. Subjects were randomized to receive a mesh-supported graft on one of these arteries; the other vessel received an untreated vein graft. Graft patency was assessed by coronary angiography nine months after surgery. The implantation of mesh grafts was simple and safe. In 10 cases, a nitinol mesh-supported venous graft was anastomosed to the circumflex artery and in 15 cases to the RCA. All patients survived the observation period. A total of 72% of the patients underwent control coronary angiography. The patency rate of mesh-supported grafts was 27.8% nine months postoperatively. Conventional vein grafts showed an 85.7% patency, and arterial grafts had a 100% patency. No complications directly related to the implantation of mesh-supported grafts were observed. The promising experimental results of mesh-supported venous grafts could not be reproduced in the study presented. A critical item seems to be correct selection of nitinol mesh diameter, the anastomotic method and fixation of the mesh tube to the venous graft.

Influence of abutment screw preload on stress distribution in marginal bone.

PubMed

Khraisat, Ameen

2012-01-01

Changes in an implant assembly after abutment connection might possibly cause deformation in the implant/abutment joint and even in the marginal bone. The aim of this study was to evaluate the influence of abutment screw preload through the implant collar on marginal bone stress without external load application. Models of three implant parts made of titanium (implant, abutment, and abutment screw) and cortical bone were built and positioned with computer-aided design software. Meshing and generation of boundary conditions, loads, and interactions were performed. Each part was meshed independently. The sole load applied to the model was a torque of 32 Ncm on the abutment screw about its axis of rotation. The implant collar was deformed axially after the screw was tightened (3 μm). This deformation resulted in 60 MPa of stress in the marginal bone. Moreover, pressure on the marginal bone in a radial direction was observed. It can be concluded that, without any external load application, abutment screw preload exerts stresses on the implant collar and the marginal bone. These findings should help guide the development of new implant/abutment joint designs that exert less stress on the marginal bone.

Osseointegrated dental implants produced via microwave processing

NASA Astrophysics Data System (ADS)

Kutty, Muralithran G.

This research is a comprehensive effort to develop osseointegrated dental implants via microwave processing. A net-shape microwave sintering procedure was employed to fabricate dental implants. Commercial pure titanium powders (-100, -200 and -325 mesh sizes) were used in this work. This process eliminates the need for machining of implants and prevents contamination. The idea was to take advantage of the peculiar way microwave couple with metallic powders, i.e. generating heat in the interior of the sample and dissipating it away through the surface. The desired features for an implant, a dense core with surface pores, is not possible via conventional sintering. Coating with hydroxyapatite via electrodeposition and chemical combustion vapor deposition was also attempted to further enhance the bioactivity of this layer. Surface roughness and area were measured using a non-contact surface profilometer to further describe the unique surface. In-vitro studies, conducted using osteoblast cells extracted from neonatal rat calvarial, showed improved cell growth on all the uncoated porous samples. However, the highest cell growth was observed on the -200 mesh size samples. The higher surface area of the -200 mesh samples is attributed to this observation. This work was able to identify the processing parameters for titanium in microwave and establishes the importance of surface area as a key parameter for cell growth on porous surfaces as compared to surface roughness.

A critical review of biologic mesh use in ventral hernia repairs under contaminated conditions.

PubMed

Primus, F E; Harris, H W

2013-02-01

We used an evidence-based approach to determine whether the promotions and claims of superiority of biologic mesh over synthetic mesh use in ventral hernia repairs (VHRs) under contaminated conditions were sound and valid. We searched the Medline database to specifically identify review articles relating to biologic mesh and VHR and critically reviewed these studies using an evidence-based approach. For the past 45 years, four clinical reviews and one systematic review have included biologic meshes as part of a larger discussion on available prosthetics for VHR. All reviews supported biologic mesh use, especially in the setting of contaminated fields. Yet, the primary literature included in these reviews and served as the basis for these conclusions consisted entirely of case series and case reports, which have the lowest level of evidence in determining scientific validity. Furthermore, the FDA has neither cleared nor approved this particular use. The cumulative data regarding biologic mesh use in VHRs under contaminated conditions does not support the claim that it is better than synthetic mesh used under the same conditions. The highly promoted and at least moderately utilized practice of placing biologic mesh in contamination is being done outside of the original intended use, and a re-evaluation of or possible moratorium on biologic mesh use in hernia surgery is seriously warranted. Alternatively, an industry-sponsored national registry of patients in whom ventral hernia repairs involved biologic mesh would substantively add to our understanding regarding how these intriguing biomaterials are being used and their overall clinical efficacy.

Localized ridge augmentation in the anterior maxilla using titanium mesh, an alloplast, and a nano-bone graft: a case report.

PubMed

Alagl, Adel S; Madi, Marwa

2018-05-01

Alveolar ridge deficiency is considered a major limitation for successful implant placement, as well as for the long-term success rate, especially in the anterior maxillary region. Various approaches have been developed to increase bone volume. Among those approaches, inlay and onlay grafts, alveolar ridge distraction, and guided bone regeneration have been suggested. The use of titanium mesh is a reliable method for ridge augmentation. We describe a patient who presented with a localized, combined, horizontal and vertical ridge defect in the anterior maxilla. The patient was treated using titanium mesh and alloplast material mixed with a nano-bone graft to treat the localized ridge deformity for future implant installation. The clinical and radiographic presentation, as well as relevant literature, are presented.

Stress Analysis on the Bone Around Five Different Dental Implants

DTIC Science & Technology

2001-10-25

University of Science and Technology, Tehran, IRAN Abstract- Implantology has a widespread application in dental cases these days. Although the life...System, in Mackinny RV: Endosteal Dental Implant, Mosby Year Book, 1991 [3] Weiss M, Titanium Fiber-Mesh Metal Implant, J. Oral Implantology , 1986...STRESS ANALYSIS ON THE BONE AROUND FIVE DIFFERENT DENTAL IMPLANTS S. M. Rajaai, S. Khorrami-mehr School of mechanical Engineering Iran

Reasons for and Against Use of Non-absorbable, Synthetic Mesh During Pelvic Organ Prolapse Repair, According to the Prolapsed Compartment.

PubMed

Kontogiannis, Stavros; Goulimi, Evangelia; Giannitsas, Konstantinos

2017-01-01

Awareness and reporting of mesh-related complications of pelvic organ prolapse repairs have increased in recent years. As a result, deciding whether to use a mesh or not has become a difficult task for urogynecologists. Our aim was to summarize reasons for and against the use of mesh in prolapse repair based on a review of relevant literature. Scopus and PubMed databases were searched for papers reporting on the efficacy and safety of native tissue versus non-absorbable, synthetic mesh prolapse repairs. Randomized controlled trials, systematic reviews, and meta-analyses were included. Evidence is presented for each vaginal compartment separately. In the anterior compartment, mesh repairs seem to offer clearly superior efficacy and durability of results compared to native tissue repairs, but with an equally clear increase in complication rates. In the isolated posterior compartment prolapse, high-quality evidence is sparse. As far as the apical compartment is concerned, sacrocolpopexy is the most efficacious, yet the most invasive procedure. Data on the comparison of transvaginal mesh versus native tissue repairs of the apical compartment are somewhat ambiguous. Given the inevitable coexistence of advantages and disadvantages of mesh use in each of the prolapsed vaginal compartments, an individualized treatment decision, based on weighing risks against benefits for each patient, seems to be the most rational approach.

Surgical mesh for ventral incisional hernia repairs: Understanding mesh design

PubMed Central

Rastegarpour, Ali; Cheung, Michael; Vardhan, Madhurima; Ibrahim, Mohamed M; Butler, Charles E; Levinson, Howard

2016-01-01

Surgical mesh has become an indispensable tool in hernia repair to improve outcomes and reduce costs; however, efforts are constantly being undertaken in mesh development to overcome postoperative complications. Common complications include infection, pain, adhesions, mesh extrusion and hernia recurrence. Reducing the complications of mesh implantation is of utmost importance given that hernias occur in hundreds of thousands of patients per year in the United States. In the present review, the authors present the different types of hernia meshes, discuss the key properties of mesh design, and demonstrate how each design element affects performance and complications. The present article will provide a basis for surgeons to understand which mesh to choose for patient care and why, and will explain the important technological aspects that will continue to evolve over the ensuing years. PMID:27054138

Utilization of flax fibers for biomedical applications.

PubMed

Michel, Sophie A A X; Vogels, Ruben R M; Bouvy, Nicole D; Knetsch, Menno L W; van den Akker, Nynke M S; Gijbels, Marion J J; van der Marel, Cees; Vermeersch, Jan; Molin, Daniel G M; Koole, Leo H

2014-04-01

Over the past decades, a large number of animal-derived materials have been introduced for several biomedical applications. Surprisingly, the use of plant-based materials has lagged behind. To study the feasibility of plant-derived biomedical materials, we chose flax (Linum usitatissimum). Flax fibers possess excellent physical-mechanical properties, are nonbiodegradable, and there is extensive know-how on weaving/knitting of them. One area where they could be useful is as implantable mesh structures in surgery, in particular for the repair of incisional hernias of the abdominal wall. Starting with a bleached flax thread, a prototype mesh was specifically knitted for this study, and its cytocompatibility was studied in vitro and in vivo. The experimental data revealed that application of flax in surgery first requires a robust method to remove endotoxins and purify the flax fiber. Such a method was developed, and purified meshes did not cause loss of cell viability in vitro. In addition, endotoxins determined using limulus amebocyte lysate test were at acceptable levels. In vivo, the flax meshes showed only mild inflammation, comparable to commercial polypropylene meshes. This study revealed that plant-derived biomaterials can provide a new class of implantable materials that could be used as surgical meshes or for other biomedical applications. Copyright © 2013 Wiley Periodicals, Inc.

[Research of the durability of connective tissue complexes formed in the implantation area of various types of allograft during the experiment].

PubMed

Ioffe, O Iu; Shvets', I M; Stetsenko, O P; Tsiura, Iu P; Tarasiuk, T V; Lamashevs'kyĭ, V P; Makovets'kyĭ, I V; Furmanov, Iu O

2014-01-01

The aim of the study is to examine in the experiment on the animals the mechanical properties of connective tissue complexes formed in alloplasty area using the intraperitoneal on lay mesh and sublay methodologies with further comparison of them. The experiment has been conducted on 12 rabbits of Russian chinchilla breed. Animals were distributed in the following way: the first group--operated by intraperitoneal on lay mesh methodology (n = 6) through implantation of composite grid Proceed with one-side celullose coating produced by "Ethicon" company. The second group--performed modeling of preperitoneal plastic using two-component composite grid with large-pores Ultrapro produced by "Ethicon" company (n = 6). For the tensometric evaluation of the strength of implant integration into the red wall was used entire area of anterior red wall together with the implanted transplant. According to the deflection diagrams and dynamometer rates defined the maximum burden rates which is equivalent of muscular tissue budge against polymeric matrix. Statistically significant distinctions during 14 days were not detected; however strength during 30 days in the first group was 3 times higher than in the second group. We consider that the methodology of intraperitoneal on lay mesh can be considered as operation of choice of surgery treatment of the umbilical hernias.

Biomimetic collagen/elastin meshes for ventral hernia repair in a rat model.

PubMed

Minardi, Silvia; Taraballi, Francesca; Wang, Xin; Cabrera, Fernando J; Van Eps, Jeffrey L; Robbins, Andrew B; Sandri, Monica; Moreno, Michael R; Weiner, Bradley K; Tasciotti, Ennio

2017-03-01

Ventral hernia repair remains a major clinical need. Herein, we formulated a type I collagen/elastin crosslinked blend (CollE) for the fabrication of biomimetic meshes for ventral hernia repair. To evaluate the effect of architecture on the performance of the implants, CollE was formulated both as flat sheets (CollE Sheets) and porous scaffolds (CollE Scaffolds). The morphology, hydrophylicity and in vitro degradation were assessed by SEM, water contact angle and differential scanning calorimetry, respectively. The stiffness of the meshes was determined using a constant stretch rate uniaxial tensile test, and compared to that of native tissue. CollE Sheets and Scaffolds were tested in vitro with human bone marrow-derived mesenchymal stem cells (h-BM-MSC), and finally implanted in a rat ventral hernia model. Neovascularization and tissue regeneration within the implants was evaluated at 6weeks, by histology, immunofluorescence, and q-PCR. It was found that CollE Sheets and Scaffolds were not only biomechanically sturdy enough to provide immediate repair of the hernia defect, but also promoted tissue restoration in only 6weeks. In fact, the presence of elastin enhanced the neovascularization in both sheets and scaffolds. Overall, CollE Scaffolds displayed mechanical properties more closely resembling those of native tissue, and induced higher gene expression of the entire marker genes tested, associated with de novo matrix deposition, angiogenesis, adipogenesis and skeletal muscles, compared to CollE Sheets. Altogether, this data suggests that the improved mechanical properties and bioactivity of CollE Sheets and Scaffolds make them valuable candidates for applications of ventral hernia repair. Due to the elevated annual number of ventral hernia repair in the US, the lack of successful grafts, the design of innovative biomimetic meshes has become a prime focus in tissue engineering, to promote the repair of the abdominal wall, avoid recurrence. Our meshes (CollE Sheets and Scaffolds) not only showed promising mechanical performance, but also allowed for an efficient neovascularization, resulting in new adipose and muscle tissue formation within the implant, in only 6weeks. In addition, our meshes allowed for the use of the same surgical procedure utilized in clinical practice, with the commercially available grafts. This study represents a significant step in the design of bioactive acellular off-the-shelf biomimetic meshes for ventral hernia repair. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Complications of pelvic organ prolapse surgery and methods of prevention.

PubMed

de Tayrac, Renaud; Sentilhes, Loic

2013-11-01

The aim was to review complications associated with pelvic organ prolapse surgery. Every 4 years and as part of the Fifth International Collaboration on Incontinence we reviewed the English-language scientific literature after searching PubMed, Medline, Cochrane library and Cochrane database of systematic reviews, published up to January 2012. Publications were classified as level 1 evidence (randomised controlled trials [RCT] or systematic reviews), level 2 (poor quality RCT, prospective cohort studies), level 3 (case series or retrospective studies) and level 4 (case reports). The highest level of evidence was utilised by the committee to make evidence-based recommendations based upon the Oxford grading system. Grade A recommendation usually depends on consistent level 1 evidence. Grade B recommendation usually depends on consistent level 2 and/or 3 studies, or "majority evidence" from RCTs. Grade C recommendation usually depends on level 4 studies or "majority evidence from level 2/3 studies or Delphi processed expert opinion. Grade D "no recommendation possible" would be used where the evidence is inadequate or conflicting and when expert opinion is delivered without a formal analytical process, such as by Delphi. Transvaginal mesh has a higher re-operation rate than native tissue vaginal repairs (grade A). If a synthetic mesh is placed via the vaginal route, it is recommended that a macroporous polypropylene monofilament mesh should be used. At sacral colpopexy mesh should not be introduced or sutured via the vaginal route and silicone-coated polyester, porcine dermis, fascia lata and polytetrafluoroethylene meshes are not recommended as grafts. Hysterectomy should also be avoided (grade B). There is no evidence to recommend routine local or systemic oestrogen therapy before or after prolapse surgery using mesh. The first cases should be undertaken with the guidance of an experienced surgeon in the relevant technique (grade C). Expert opinion suggests that by whatever the surgical route pre-operative urinary tract infections are treated, smoking is ceased and antibiotic prophylaxis is undertaken. It is recommended that a non-absorbable synthetic mesh should not be inserted into the rectovaginal septum when a rectal injury occurs. The placement of a non-absorbable synthetic mesh into the vesicovaginal septum may be considered after a bladder injury has been repaired, if the repair is considered to be satisfactory. It is possible to perform a hysterectomy in association with the introduction of a non-absorbable synthetic mesh inserted vaginally, but this is not recommended routinely.

[Biodegradable synthetic implant materials : clinical applications and immunological aspects].

PubMed

Witte, F; Calliess, T; Windhagen, H

2008-02-01

In the last decade biodegradable synthetic implant materials have been established for various clinical applications. Ceramic materials such as calcium phosphate, bioglass and polymers are now routinely used as degradable implants in the clinical practice. Additionally these materials are now also used as coating materials or as microspheres for controlled drug release and belong to a series of examples for applications as scaffolds for tissue engineering. Because immense local concentrations of degradation products are produced during biodegradation, this review deals with the question whether allergic immune reactions, which have been reported for classical metallic and organic implant materials, also play a role in the clinical routine for synthetic biodegradable materials. Furthermore, possible explanatory theories will be developed to clarify the lack of clinical reports on allergy or sensitization to biodegradable synthetic materials.

Past, Present and Future of Surgical Meshes: A Review.

PubMed

Baylón, Karen; Rodríguez-Camarillo, Perla; Elías-Zúñiga, Alex; Díaz-Elizondo, Jose Antonio; Gilkerson, Robert; Lozano, Karen

2017-08-22

Surgical meshes, in particular those used to repair hernias, have been in use since 1891. Since then, research in the area has expanded, given the vast number of post-surgery complications such as infection, fibrosis, adhesions, mesh rejection, and hernia recurrence. Researchers have focused on the analysis and implementation of a wide range of materials: meshes with different fiber size and porosity, a variety of manufacturing methods, and certainly a variety of surgical and implantation procedures. Currently, surface modification methods and development of nanofiber based systems are actively being explored as areas of opportunity to retain material strength and increase biocompatibility of available meshes. This review summarizes the history of surgical meshes and presents an overview of commercial surgical meshes, their properties, manufacturing methods, and observed biological response, as well as the requirements for an ideal surgical mesh and potential manufacturing methods.

Application of Tissue Engineering to Pelvic Organ Prolapse and Stress Urinary Incontinence.

PubMed

Chapple, Christopher R; Osman, Nadir I; Mangera, Altaf; Hillary, Christopher; Roman, Sabiniano; Bullock, Anthony; Macneil, Sheila

2015-05-01

Synthetic or biological materials can be used for the surgical repair of pelvic organ prolapse (POP) or stress urinary incontinence (SUI). While non-degradable synthetic mesh has a low failure rate, it is prone to complications such as infection and erosion, particularly in the urological/gynecological setting when subject to chronic influences of gravity and intermittent, repetitive strain. Biological materials have lower complication rates, although allografts and xenografts have a high risk of failure and the theoretical risk of infection. Autografts are used successfully for the treatment of SUI and are not associated with erosion; however, can lead to morbidity at the donor site. Tissue engineering has thus become the focus of interest in recent years as researchers seek an ideal tissue remodeling material for urogynecological repair. Herein, we review the directions of current and future research in this exciting field. Electrospun poly-L-lactic acid (PLA) and porcine small intestine submucosa (SIS) are two promising scaffold material candidates. Adipose-derived stem cells (ADSCs) appear to be a suitable cell type for scaffold seeding, and cells grown on scaffolds when subjected to repetitive biaxial strain show more appropriate biomechanical properties for clinical implantation. After implantation, an appropriate level of acute inflammation is important to precipitate moderate fibrosis and encourage tissue strength. New research directions include the use of bioactive materials containing compounds that may help facilitate integration of the new tissue. More research with longer follow-up is needed to ascertain the most successful and safe methods and materials for pelvic organ repair and SUI treatment. © 2015 Wiley Publishing Asia Pty Ltd.

Bone bonding strength of diamond-structured porous titanium-alloy implants manufactured using the electron beam-melting technique.

PubMed

Hara, Daisuke; Nakashima, Yasuharu; Sato, Taishi; Hirata, Masanobu; Kanazawa, Masayuki; Kohno, Yusuke; Yoshimoto, Kensei; Yoshihara, Yusuke; Nakamura, Akihiro; Nakao, Yumiko; Iwamoto, Yukihide

2016-02-01

The present study examined the bone bonding strength of diamond-structured porous titanium-alloy (Porous-Ti-alloy) manufactured using the electron beam-melting technique in comparison with fiber mesh-coated or rough-surfaced implants. Cylindrical implants with four different pore sizes (500, 640, 800, and 1000μm) of Porous-Ti-alloy, titanium fiber mesh (FM), and surfaces roughened by titanium arc spray (Ti-spray) were implanted into the distal femur of rabbits. Bone bonding strength and histological bone ingrowth were evaluated at 4 and 12weeks after implantation. The bone bonding strength of Porous-Ti-alloy implants (640μm pore size) increased over time from 541.4N at 4weeks to 704.6N at 12weeks and was comparable to that of FM and Ti-spray implants at both weeks. No breakage of the porous structure after mechanical testing was found with Porous-Ti-alloy implants. Histological bone ingrowth that increased with implantation time occurred along the inner structure of Porous-Ti-alloy implants. There was no difference in bone ingrowth in Porous-Ti-alloy implants with pore sizes among 500, 640, and 800μm; however, less bone ingrowth was observed with the 1000μm pore size. These results indicated Porous-Ti-alloy implants with pore size under 800μm provided biologically active and mechanically stable surface for implant fixation to bone, and had potential advantages for weight bearing orthopedic implants such as acetabular cups. Copyright © 2015 Elsevier B.V. All rights reserved.

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain

PubMed Central

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G.; Viveros, Robert D.; Lieber, Charles M.

2017-01-01

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2–12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future. PMID:28533392

Biomechanical and Histologic Evaluation of LifeMesh™: A Novel Self-Fixating Mesh Adhesive.

PubMed

Shahan, Charles P; Stoikes, Nathaniel N; Roan, Esra; Tatum, James; Webb, David L; Voeller, Guy R

2018-04-01

Mesh fixation with the use of adhesives results in an immediate and total surface area adhesion of the mesh, removing the need for penetrating fixation points. The purpose of this study was to evaluate LifeMesh™, a prototype mesh adhesive technology which coats polypropylene mesh. The strength of the interface between mesh and tissue, inflammatory responses, and histology were measured at varying time points in a swine model, and these results were compared with sutures. Twenty Mongrel swine underwent implantation of LifeMesh™ and one piece of bare polypropylene mesh secured with suture (control). One additional piece of either LifeMesh™ or control was used for histopathologic evaluation. The implants were retrieved at 3, 7, and 14 days. Only 3- and 7-day specimens underwent lap shear testing. On Day 3, LifeMesh™ samples showed considerably less contraction than sutured samples. The interfacial strength of Day 3 LifeMesh™ samples was similar to that of sutured samples. At seven days, LifeMesh™ samples continued to show significantly less contraction than sutured samples. The strength of fixation at seven days was greater in the control samples. The histologic findings were similar in LifeMesh™ and control samples. LifeMesh™ showed significantly less contraction than sutured samples at all measured time points. Although fixation strength was similar at three days, the interfacial strength of LifeMesh™ remained unchanged, whereas sutured controls increased by day 7. With histologic equivalence, considerably less contraction, and similar early fixation strength, LifeMesh™ is a viable mesh fixation technology.

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain.

PubMed

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G; Viveros, Robert D; Lieber, Charles M

2017-06-06

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2-12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future.

The numerical simulation study of hemodynamics of the new dense-mesh stent

NASA Astrophysics Data System (ADS)

Ma, Jiali; Yuan, Zhishan; Yu, Xuebao; Feng, Zhaowei; Miao, Weidong; Xu, Xueli; Li, Juntao

2017-09-01

The treatment of aortic aneurysm in new dense mesh stent is based on the principle of hemodynamic changes. But the mechanism is not yet very clear. This paper analyzed and calculated the hemodynamic situation before and after the new dense mesh stent implanting by the method of numerical simulation. The results show the dense mesh stent changed and impacted the blood flow in the aortic aneurysm. The changes include significant decrement of blood velocity, pressure and shear forces, while ensuring blood can supply branches, which means the new dense mesh stent's hemodynamic mechanism in the treatment of aortic aneurysm is clearer. It has very important significance in developing new dense mesh stent in order to cure aortic aneurysm.

Effects of polyglactin mesh combined with resorbable calcium carbonate or replamineform hydroxyapatite on periodontal repair in dogs.

PubMed

Moon, I S; Chai, J K; Cho, K S; Wikesjö, U M; Kim, C K

1996-10-01

This study evaluates periodontal repair and biomaterial reaction following implantation of a polyglactin mesh with or without porous resorbable calcium carbonate (RCC) or porous replamineform hydroxyapatite (RHA) in conjunction with reconstructive surgery. Ligature- and surgically-induced interproximal periodontal defects of left and right mandibular premolar teeth in 7 dogs were used. Bilaterally, mesial defects of the 2nd, 3rd and 4th premolar teeth were treated with polyglactin mesh, polyglactin mesh and RHA, or polyglactin mesh and RCC, respectively. The polyglactin mesh, shaped according to the contour of the defect, was adapted to the experimental teeth; its coronal margin positioned immediately apical to the cemento-enamel junction. Gingival flap margins were adapted and sutured to cover the polyglactin mesh completely. Clinical healing was generally uneventful. The dogs were sacrificed to provide block sections for histologic evaluation at 1, 3, 6, 12, 26, 32 and 56 weeks following wound closure. Generally, cementum regeneration was observed beginning at week 6 in all groups. Bone regeneration was observed from week 3 in polyglactin mesh-treated groups, and from week 6 in polyglactin mesh+RCC or polyglactin mesh+RHA treated groups. Bone regeneration appeared enhanced in polyglactin mesh+RCC or polyglactin mesh+RHA treated defects at week 12 and 26, with little difference between the three experimental conditions at week 56. Polyglactin mesh degradation was observed at week 3 and appeared complete at week 12. The RHA did not appear to resorb, while the RCC was gradually replaced by bone from week 3. Within limitations of the study conditions, periodontal regeneration was observed following implantation of a polyglactin mesh with or without RCC or RHA in conjunction with reconstructive surgery. As a conclusion, there seems to be no significant difference in periodontal regeneration after 12 months of healing between the group treated with the membrane only, and the group treated with the membrane and the bone substitution material. Changes in connective fiber orientation over the 1st 12 weeks of healing may suggest that "fibrous encapsulation" observed in earlier studies may only represent a transient stage in periodontal regeneration.

Poly(ε-caprolactone) Microfiber Meshes for Repeated Oil Retrieval

PubMed Central

Hersey, J. S.; Yohe, S. T.; Grinstaff, M. W.

2016-01-01

Electrospun non-woven poly(ε-caprolactone) (PCL) microfiber meshes are described as biodegradable, mechanically robust, and reusable polymeric oil sorbents capable of selectively retrieving oil from simulated oil spills in both fresh and seawater scenarios. Hydrophobic PCL meshes have >99.5% (oil over water) oil selectivity and oil absorption capacities of ~10 grams of oil per gram of sorbent material, which is shown to be a volumetrically driven process. Both the oil selectivity and absorption capacity remained constant over several oil absorption and vacuum assisted retrieval cycles when removing crude oil or mechanical pump oil from deionized water or simulated seawater mixtures. Finally, when challenged with surfactant stabilized water-in-oil emulsions, the PCL meshes continued to show selective oil absorption. These studies add to the knowledge base of synthetic oil sorbents highlighting a need for biodegradable synthetic oil sorbents which balance porosity and mechanical integrity enabling reuse, allowing for the efficient recovery of oil after an accidental oil spill. PMID:26989490

[INFLUENCE OF TITANIUM COATING ON THE BIOCOMPATIBILITY OF POLYPROPYLENE IMPLANTS].

PubMed

Babichenko, I I; Kazantsev, A A; Titarov, D L; Shemyatovsky, K A; Ghevondian, N M; Melchenko, D; Alekhin, A I

2016-01-01

Comparative analysis of the proliferative activity of inflammatory cells and distribution of collagen types I and III was carried out around the net materials of polypropylene and titanium coating polypropylene using im- munohistochemical method and polarization microscopy. Experimental modeling of implanted mesh material were made in the soft tissues of the lumbar region of rats. On the 7th postoperative day, quantitative analysis of proliferating cells delected using antibodies to the Ki-67 protein showed, a significant decrease (p < 0.001) in the number of proliferating cells around the network elements of the polypropylene (29.1 ± 5.7 %), when com- pared to similar figures of infiltrates in titanium coating polypropylene (33.6 ± 3.1 %). Similar patterns were found on the 30th day of the experiment--15.9 ± 4.3 and 26.9 ± 3.6%--respectively (p < 0.001). Different types of collagen fibers in the granulomas around various types of implanted mesh material were detected on sections stained with Sirius red at polarizing light. On the 7th day after surgery, the ratio of collagen fibers ty- pe I and III in granulomas around the mesh material made of polypropylene was 1.085 ± 0.022 and this rati around materials of titanium coated polypropylene was higher--1.107 ± 0.013 (p = 0.017). On the 30th posto- perative day in the interface area ratio I/III collagen significantly increased and amounted to 1.174 ± 0.036 and 1.246 ± 0.102, respectively (p = 0.045). Assessing the impact of the use of titanium as a coating on the po- lypropylene, it can be argued that it promotes the formation of collagen I type and a more mature connective tis- sue around the mesh of the implants.

Minimal Invasive Linea Alba Reconstruction for the Treatment of Umbilical and Epigastric Hernias with Coexisting Rectus Abdominis Diastasis.

PubMed

Köhler, Gernot; Fischer, Ines; Kaltenböck, Richard; Schrittwieser, Rudolf

2018-04-05

Patients with umbilical or epigastric hernias benefit from mesh- based repairs, and even more so if a concomitant rectus diastasis (RD) is present. The ideal technique is, however, still under debate. In this study we introduce the minimal invasive linea alba reconstruction (MILAR) with the supraaponeurotic placement of a fully absorbable synthetic mesh. Midline reconstruction with anterior rectus sheath repair and mesh augmentation by an open approach is a well-known surgical technique for ventral hernia repair. Between December 1, 2016, and November 30, 2017, 20 patients with symptomatic umbilical and/or epigastric hernias, and coexisting RD underwent a minimally invasive complete reconstruction of the midline through a small access route. The inner part of both incised and medialized anterior rectus sheaths was replaced by a fully absorbable synthetic mesh placed in a supraaponeurotic position. Patients were hospitalized for an average of 4 days and the mean operating time was 79 minutes. The mean hernia defect size was 1.5 cm in diameter and the mean mesh size was recorded as 15.8 cm in length and 5.2 cm in width. Two patients sustained surgical postoperative complications in terms of symptomatic seroma occurrences with successful interventional treatment.The early results (mean follow-up period of 5 months) showed no recurrences and only 1 patient reported occasional pain following exertion without rest. MILAR is a modification of the recently published endoscopic linea alba reconstruction restoring the normal anatomy of the abdominal wall. A new linea alba is formed with augmentation of autologous tissue consisting of the plicated anterior rectus sheaths. Supraaponeurotic placement of a fully absorbable synthetic mesh eliminates potential long-term mesh-associated complications. Regarding MILAR, there is no need for endoscopic equipment due to the uniquely designed flexible lighted retractors, meaning one assistant less is required.

Past, Present and Future of Surgical Meshes: A Review

PubMed Central

Baylón, Karen; Rodríguez-Camarillo, Perla; Elías-Zúñiga, Alex; Díaz-Elizondo, Jose Antonio; Gilkerson, Robert; Lozano, Karen

2017-01-01

Surgical meshes, in particular those used to repair hernias, have been in use since 1891. Since then, research in the area has expanded, given the vast number of post-surgery complications such as infection, fibrosis, adhesions, mesh rejection, and hernia recurrence. Researchers have focused on the analysis and implementation of a wide range of materials: meshes with different fiber size and porosity, a variety of manufacturing methods, and certainly a variety of surgical and implantation procedures. Currently, surface modification methods and development of nanofiber based systems are actively being explored as areas of opportunity to retain material strength and increase biocompatibility of available meshes. This review summarizes the history of surgical meshes and presents an overview of commercial surgical meshes, their properties, manufacturing methods, and observed biological response, as well as the requirements for an ideal surgical mesh and potential manufacturing methods. PMID:28829367

The impact of hydrophobic hernia mesh coating by omega fatty acid on atraumatic fibrin sealant fixation.

PubMed

Gruber-Blum, S; Brand, J; Keibl, C; Redl, H; Fortelny, R H; May, C; Petter-Puchner, A H

2015-08-01

Fibrin sealant (FS) is a safe and efficient fixation method in open intraperitoneal hernia repair. While favourable results have been achieved with hydrophilic meshes, hydrophobic (such as Omega fatty acid coated) meshes (OFM) have not been specifically assessed so far. Atrium C-qur lite(®) mesh was tested in rats in models of open onlay and intraperitoneal hernia repair. 44 meshes (2 × 2 cm) were implanted in 30 male Sprague-Dawley rats in open (n = 2 meshes per animal) and intraperitoneal technique (IPOM; n = 1 mesh per animal). Animals were randomised to four groups: onlay and IPOM sutured vs. sealed. Follow-up was 6 weeks, sutured groups serving as controls. Evaluation criteria were mesh dislocation, adhesions and foreign body reaction. FS provided a reliable fixation in onlay technique, whereas OFM meshes dislocated in the IPOM position when sealed only. FS mesh fixation was safe with OFM meshes in open onlay repair. Intraperitoneal placement of hydrophobic meshes requires additional fixation and cannot be achieved with FS alone.

Impact of MPEG-4 3D mesh coding on watermarking algorithms for polygonal 3D meshes

NASA Astrophysics Data System (ADS)

Funk, Wolfgang

2004-06-01

The MPEG-4 multimedia standard addresses the scene-based composition of audiovisual objects. Natural and synthetic multimedia content can be mixed and transmitted over narrow and broadband communication channels. Synthetic natural hybrid coding (SNHC) within MPEG-4 provides tools for 3D mesh coding (3DMC). We investigate the robustness of two different 3D watermarking algorithms for polygonal meshes with respect to 3DMC. The first algorithm is a blind detection scheme designed for labelling applications that require high bandwidth and low robustness. The second algorithm is a robust non-blind one-bit watermarking scheme intended for copyright protection applications. Both algorithms have been proposed by Benedens. We expect 3DMC to have an impact on the watermarked 3D meshes, as the algorithms used for our simulations work on vertex coordinates to encode the watermark. We use the 3DMC implementation provided with the MPEG-4 reference software and the Princeton Shape Benchmark model database for our simulations. The watermarked models are sent through the 3DMC encoder and decoder, and the watermark decoding process is performed. For each algorithm under consideration we examine the detection properties as a function of the quantization of the vertex coordinates.

An Evaluation of Parastomal Hernia Repair Using the Americas Hernia Society Quality Collaborative.

PubMed

Fox, Sarah S; Janczyk, Randy; Warren, Jeremy A; Carbonell, Alfredo M; Poulose, Benjamin K; Rosen, Michael J; Hope, William W

2017-08-01

The purpose of this review was to evaluate outcomes relating to parastomal hernia repair. Data from the Americas Hernia Society Quality Collaborative were used to identify patients undergoing parastomal hernia repair from 2013 to 2016. Parastomal hernia repairs were compared with other repairs using Pearson's test and Wilcoxon test with a P value <0.05 considered significant. Parastomal hernia repairs were performed in 311 patients. Techniques of repair include open in 85 per cent and laparoscopic in 15 per cent. Mesh was used in 92 per cent with keyhole in 34 per cent, flat mesh in 33 per cent, and Sugarbaker in 25 per cent. Mesh types were permanent synthetic in 79 per cent, biologic in 13 per cent, absorbable synthetic in 6 per cent, and hybrid synthetic/biologic in 2 per cent. Most common location for mesh was sublay in 84 per cent followed by onlay in 14 per cent and inlay in 2 per cent with 59 per cent of patients undergoing a myofascial release. Ostomy disposition included ostomy left in situ (47%), moved to a new site (18%), taken down (22%), and rematured in same location in (13%). Outcomes related to parastomal hernia repair included 10 per cent surgical site infection, 24 per cent surgical site occurrence, and 12 per cent surgical site occurrences requiring procedural interventions with a 13 per cent readmission rate and 6 per cent reoperation rate. When comparing parastomal hernias with other ventral hernia repairs, parastomal hernias had a significantly higher surgical site infection, surgical site occurrence, surgical site occurrences requiring procedural intervention, readmission, reoperation rate, and length of stay, and were less commonly performed laparoscopically (P < 0.05). Most parastomal hernias are being repaired open with synthetic mesh in the sublay position. Less favorable outcomes of parastomal hernia repair when compared with other ventral hernia repairs are likely related to the complexity of parastomal hernia repair.

Reconstruction of Midface and Orbital Wall Defects After Maxillectomy and Orbital Content Preservation With Titanium Mesh and Fascia Lata: 3-Year Follow-Up.

PubMed

Motiee-Langroudi, Maziar; Harirchi, Iraj; Amali, Amin; Jafari, Mehrdad

2015-12-01

To describe the authors' experience in the reconstruction of patients after total maxillectomy with preservation of orbital contents for maxillary tumors using titanium mesh and autogenous fascia lata, where no setting for free flap reconstruction is available. Twelve consecutive patients with paranasal sinus tumors underwent total maxillectomy without orbital exenterations and primary reconstruction. The defects were reconstructed by titanium mesh in combination with autogenous fascia lata in the orbital floor performed by 1 surgical team. Titanium mesh (0.2 mm thick) was contoured and fixed to reconstruct the orbital floor and obtain midface projection. Fascia lata was used to cover the titanium mesh along the orbital floor to prevent fat entrapment in the mesh holes. The most common pathology was squamous cell carcinoma (50%). Patients' mean age was 45.66 years (33 to 74 yr). The mean follow-up period was 35.2 months (30 to 49 months). During follow-up, no infection or foreign body reaction was encountered. Extrusion of titanium mesh occurred in 4 patients who underwent postoperative radiotherapy. Two cases of mild diplopia at extreme gaze occurred early during the postoperative period that resolved after a few months. Placing fascia lata between the titanium mesh surface of the orbital implant and the orbital contents was successful in preventing long-term diplopia or dystopia. Nevertheless, exposure of the titanium implant through the skin surface represented a complication of this technique in 25% of patients. Further studies are required with head-to-head comparisons of artificial materials and free flaps for reconstruction of maxillectomy defects. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Synthetic mesh in the surgical repair of pelvic organ prolapse: current status and future directions.

PubMed

Keys, Tristan; Campeau, Lysanne; Badlani, Gopal

2012-08-01

In light of the recent Food and Drug Administration public health notification regarding complications associated with transvaginally placed mesh for pelvic organ prolapse (POP) repair, we review recent literature to evaluate current outcomes and complication data, analyze the clinical need for mesh on the basis of genetic and biochemical etiologies of POP, and investigate trends of mesh use via an American Urological Association member survey. Mesh-based techniques show better anatomic results than traditional repair of anterior POP, but subjective outcomes are equivalent. Further research and Level I evidence are required before mesh-based repair of POP can be standardized. Adequate surgical training and patient selection should decrease complication rates. Published by Elsevier Inc.

Safety of silastic sheet for orbital wall reconstruction.

PubMed

Moon, Seong June; Suh, Hyun Suk; Park, Bo Young; Kang, So Ra

2014-07-01

Many implants are being used for the reconstruction of orbital wall fractures. The effect of the choice of implant for the reconstruction of an orbital wall fracture on the surgical outcome is under debate. The purpose of this article is to compare the outcomes of orbital wall reconstruction of small orbital wall fractures on the basis of the implants used. The authors conducted a retrospective study using electronic databases. Between March 2001 and December 2012, 461 patients with orbital wall fractures were included in this study. Among them, 431 patients in whom the fracture size was less than 300 mm(2) were analyzed. The fracture size was calculated using computed tomography scans of the orbit in the sagittal and coronal images. Cases in which the fracture size was less than 300 mm(2) were included in this study. One hundred and twenty-nine patients were treated with silastic sheets; 238 patients were treated with titanium meshes; and absorbable meshes were used in the case of 64 patients. Overall, 13 patients required revision, and the revision rate was 3.0%. The revision rate of the silastic sheet group was 5.4%. In the multivariable analysis, the revision rate of the group reconstructed with silastic sheets was highly statistically significant (P=0.043, odds ratio=3.65). However, other factors such as age, sex, fracture type, and fracture size were not significant. Reconstruction of orbital wall fractures with silastic sheets may cause more complications than that with other materials such as titanium meshes and absorbable meshes.

Porous coatings from wire mesh for bone implants

DOEpatents

Sump, Kenneth R.

1986-01-01

A method of coating areas of bone implant elements and the resulting implant having a porous coating are described. Preselected surface areas are covered by a preform made from continuous woven lengths of wire. The preform is compressed and heated to assure that diffusion bonding occurs between the wire surfaces and between the surface boundaries of the implant element and the wire surfaces in contact with it. Porosity is achieved by control of the resulting voids between the bonded wire portions.

Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology

PubMed Central

Fu, Tian-Ming; Hong, Guosong; Viveros, Robert D.; Zhou, Tao

2017-01-01

Implantable electrical probes have led to advances in neuroscience, brain−machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases. PMID:29109247

Use of Synthetic Osteochondral Implants to Treat Bilateral Shoulder Osteochondritis Dissecans in a Dog.

PubMed

Danielski, Alan; Farrell, Michael

2018-06-20

 An 8-month-old American Bulldog was presented for assessment of bilateral thoracic limb lameness. Computed tomographic imaging revealed large, deep osteochondritis dissecans lesions in both humeral heads.  The osteochondritis dissecans lesions were debrided and the exposed subchondral defects were prepared to receive synthetic grafts. Circular implants consisting of a surface layer of polycarbonate urethane and a deep layer of lattice-type titanium were implanted into the osteochondral defects to reconstruct the articular surface topography. Follow-up clinical examination 1.5, 3 and 9months postoperatively revealed a lack of signs of shoulder pain and resolution of thoracic limb lameness. Nine-month follow-up radiographs showed radiographic evidence of osteointegration of both implants.  Synthetic osteochondral implantation in the caudocentral aspect of the humeral head appeared technically feasible and effective in resolving lameness caused by humeral head osteochondritis dissecans. Schattauer GmbH Stuttgart.

Treatment of calvarial defects by resorbable and non-resorbable sonic activated polymer pins and mouldable titanium mesh in two dogs: a case report.

PubMed

Langer, Pierre; Black, Cameron; Egan, Padraig; Fitzpatrick, Noel

2018-06-22

To date, calvarial defects in dogs have traditionally been addressed with different types of implants including bone allograft, polymethylmethacrylate and titanium mesh secured with conventional metallic fixation methods. This report describes the use of an absorbable and non absorbable novel polymer fixation method, Bonewelding® technology, in combination with titanium mesh for the repair of calvarial defects in two dogs. The clinical outcomes and comparative complication using resorbable and non-resorbable thermoplastic pins were compared. This report of two cases documents the repair of a traumatic calvarial fracture in an adult male Greyhound and a cranioplasty following frontal bone tumor resection in an adult female Cavalier King Charles Spaniel with the use of a commercially available titanium mesh secured with an innovative thermoplastic polymer screw system (Bonewelding®). The treatment combination aimed to restore cranial structure, sinus integrity and cosmetic appearance. A mouldable titanium mesh was cut to fit the bone defect of the frontal bone and secured with either resorbable or non-resorbable polymer pins using Bonewelding® technology. Gentamycin-impregnated collagen sponge was used intraoperatively to assist with sealing of the frontal sinuses. Calvarial fracture and post-operative implant positioning were advised using computed tomography. A satisfactory restoration of skull integrity and cosmetic result was achieved, and long term clinical outcome was deemed clinically adequate with good patient quality of life. Postoperative complications including rostral mesh uplift with minor associated clinical signs were encountered when resorbable pins were used. No postoperative complications were experienced in non-resorbable pins at 7 months follow-up, by contrast mesh uplift was noted 3 weeks post-procedure in the case treated using absorbable pins. The report demonstrates the innovative use of sonic-activated polymer pins (Bonewelding® technology) alongside titanium mesh is a suitable alternative technique for skull defect repair in dogs. The use of Bonewelding® may offer advantages in reduction of surgical time. Further, ultrasonic pin application may be less invasive than alternative metallic fixation and potentially reduces bone trauma. Polymer systems may offer enhanced mesh-bone integration when compared to traditional metallic implants. The use of polymer pins demonstrates initial potential as a fixation method in cranioplasty. Initial findings in a single case comparison indicate a possible advantage in the use of non-absorbable over the absorbable systems to circumvent complications associated with variable polymer degradation, further long term studies with higher patient numbers are required before reliable conclusions can be made.

Experiments with the Mesoscale Atmospheric Simulation System (MASS) using the synthetic relative humidity

NASA Technical Reports Server (NTRS)

Chang, Chia-Bo

1994-01-01

This study is intended to examine the impact of the synthetic relative humidity on the model simulation of mesoscale convective storm environment. The synthetic relative humidity is derived from the National Weather Services surface observations, and non-conventional sources including aircraft, radar, and satellite observations. The latter sources provide the mesoscale data of very high spatial and temporal resolution. The synthetic humidity data is used to complement the National Weather Services rawinsonde observations. It is believed that a realistic representation of initial moisture field in a mesoscale model is critical for the model simulation of thunderstorm development, and the formation of non-convective clouds as well as their effects on the surface energy budget. The impact will be investigated based on a real-data case study using the mesoscale atmospheric simulation system developed by Mesoscale Environmental Simulations Operations, Inc. The mesoscale atmospheric simulation system consists of objective analysis and initialization codes, and the coarse-mesh and fine-mesh dynamic prediction models. Both models are a three dimensional, primitive equation model containing the essential moist physics for simulating and forecasting mesoscale convective processes in the atmosphere. The modeling system is currently implemented at the Applied Meteorology Unit, Kennedy Space Center. Two procedures involving the synthetic relative humidity to define the model initial moisture fields are considered. It is proposed to perform several short-range (approximately 6 hours) comparative coarse-mesh simulation experiments with and without the synthetic data. They are aimed at revealing the model sensitivities should allow us both to refine the specification of the observational requirements, and to develop more accurate and efficient objective analysis schemes. The goal is to advance the MASS (Mesoscal Atmospheric Simulation System) modeling expertise so that the model output can provide reliable guidance for thunderstorm forecasting.

Effect of abutment angulation on the strain on the bone around an implant in the anterior maxilla: a finite element study.

PubMed

Saab, Xavier E; Griggs, Jason A; Powers, John M; Engelmeier, Robert L

2007-02-01

Angled abutments are often used to restore dental implants placed in the anterior maxilla due to esthetic or spatial needs. The effect of abutment angulation on bone strain is unknown. The purpose of the current study was to measure and compare the strain distribution on the bone around an implant in the anterior maxilla using 2 different abutments by means of finite element analysis. Two-dimensional finite element models were designed using software (ANSYS) for 2 situations: (1) an implant with a straight abutment in the anterior maxilla, and (2) an implant with an angled abutment in the anterior maxilla. The implant used was 4x13 mm (MicroThread). The maxillary bone was modeled as type 3 bone with a cortical layer thickness of 0.5 mm. Oblique loads of 178 N were applied on the cingulum area of both models. Seven consecutive iterations of mesh refinement were performed in each model to observe the convergence of the results. The greatest strain was found on the cancellous bone, adjacent to the 3 most apical microthreads on the palatal side of the implant where tensile forces were created. The same strain distribution was observed around both the straight and angled abutments. After several iterations, the results converged to a value for the maximum first principal strain on the bone of both models, which was independent of element size. Most of the deformation occurred in the cancellous bone and ranged between 1000 and 3500 microstrain. Small areas of cancellous bone experienced strain above the physiologic limit (4000 microstrain). The model predicted a 15% higher maximum bone strain for the straight abutment compared with the angled abutment. The results converged after several iterations of mesh refinement, which confirmed the lack of dependence of the maximum strain at the implant-bone interface on mesh density. Most of the strain produced on the cancellous and cortical bone was within the range that has been reported to increase bone mass and mineralization.

[The Open Retromuscular Preperitoneal Mesh Repair of the Incisional Lateral Hernia - Technique and Results of a Prospective Cohort Study].

PubMed

Isemer, Friedrich-Eckart; Dietz, Ulrich; Ackermann, Maximilian

2018-05-18

Surgical approaches to flank hernias have been poorly standardised. The most demanding issues in intermuscular net insertion are the limited area in the dorsal direction and the difficulties in fixing the net to the costal arch or the iliac crest. This is why many different surgical procedures have been published. From August 2015 to October 2016, nine patients with a primary incisional lateral hernia received open retromuscular preperitoneal mesh repair. In intermuscular mesh placement, the mesh size must be smaller at smaller values of the CPA (costopelvic angle). On the dorsal side of the reference stretch RS of 10 cm between costal arch and iliac crest, fixations are necessary to achieve stability. Retroperitoneal preperitoneal net implantation is unrestricted by the patient's anatomy. The placement of the mesh is similar to the Stoppa procedure and almost any size can be used with little fixation. Remodeling of the abdominal wall can be comfortably achieved. All 9 patients underwent retromuscular preperitoneal mesh repair. The hernia size was 92.85 cm 2 with a corresponding mesh size of 426.22 cm 2 . No adverse side effects or surgical complications were observed; the length of hospital stay was between 3 to 7 days; the follow up was 3 to 18 months, with a mean follow-up of 9.1 months. In a follow-up questionnaire, the patients reported a high satisfaction rate with a grade of 1,2 (school mark); there was no recurrence. The pain level decreased from VAS grade 4 preoperatively to 1.2 postoperatively. 7 patients had no pain at all. In conclusion, adequate overlap of the implanted mesh can be achieved in the preperitoneal retromuscular space even in large hernias. Fixation of the mesh to the costal arch or the iliac crest is not necessary and would only induce postoperative pain. Long-term stability depends on the size of the mesh. Remodeling of the abdominal wall with closure of the fascia above the mesh can be easily achieved. Georg Thieme Verlag KG Stuttgart · New York.

[Is the use of synthetic mesh by vaginal route decrease the risk of cystocele recurrence? Clinical practice guidelines].

PubMed

Le Normand, L; Deffieux, X; Donon, L; Fatton, B; Cour, F

2016-07-01

The use of prosthetic surgery by vaginal route has been widely used to try to reduce the risk of prolapse recurrence in the surgical treatment of vaginal cystoceles. Specific complications including type of erosion have led to randomized studies comparing surgery by vaginal route with and without use of Mesh. This work is based on a systematic review of the literature (PubMed, Medline, Cochrane Library, Cochrane database of systemactic reviews, EMBASE) for meta-analyzes, randomized trials, registries, literature reviews, controlled studies and major not controlled studies, published on the subject. Its implementation has followed the methodology of the HAS on the recommendations for clinical practice, with a scientific argument (with the level of evidence, NP) and a recommendation grade (A, B, C, and professional agreement (AP)). The use of inter-vesicovaginal synthetic mesh improves the anatomical result compared to the autologous surgery for the treatment of cystocele (NP1). However, there is no difference in the functional outcome and there is an increase in the number of reoperations related to specific complications, including vaginal erosions. If the use of inter-vesicovaginal synthetic mesh improves the anatomical result compared to the autologous surgery for the treatment of cystocele (NP1), no difference in functional outcome and the increased number of related reoperations specific complications including vaginal erosions, do not argue for the systematic use of mesh in the treatment of primary cystocele. It must be discussed case by case basis taking into account a risk-benefit uncertain at long-term (grade B). Its use should be supported by additional studies focused on specific populations at risk of recurrence. © 2016 Published by Elsevier Masson SAS. © 2016 Elsevier Masson SAS. Tous droits réservés.

Prophylactic mesh at end-colostomy construction reduces parastomal hernia rate: a randomized trial.

PubMed

Lambrecht, J R; Larsen, S G; Reiertsen, O; Vaktskjold, A; Julsrud, L; Flatmark, K

2015-10-01

Parastomal hernia (PSH) is the most common complication of an end-colostomy and about one-quarter of patients need operative repair, which is often unsuccessful. A randomized trial was carried out to compare the results of using mesh or no mesh at the time of formation of a colostomy with the clinical identification of PSH as the primary outcome. In this two-centre randomized trial (Oslo University Hospital and Sykehuset Innlandet Hospital Trust, Norway), patients with rectal cancer undergoing open pelvic surgery were randomized to receive a retromuscular synthetic mesh (study group, n = 32) or no mesh (control group, n = 26) at the time of end-colostomy formation. Postoperative follow up was not blinded and included clinical examination and routine CT. The median period of follow up was 40 (range: 84) months. There were no differences in demographic variables or complications between the study and control groups. PSH developed in two patients of the study group and in 12 of the control group [OR = 0.04 (95% CI: 0.01-0.30) and hazard ratio 0.134 (95% CI: 0.030-0.603); P < 0.001]. The number needed to treat to avoid one PSH was 2.5 patients. CT demonstrated an increase over time in the size of the fascial orifice in patients with PSH without mesh prophylaxis, in contrast to a stable size in patients with mesh and in the control patients who did not develop PSH. The retromuscular insertion of synthetic mesh at the time of formation of an end-colostomy reduced the risk of PSH. Colorectal Disease © 2015 The Association of Coloproctology of Great Britain and Ireland.

First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial.

PubMed

Bittner, James G; El-Hayek, Kevin; Strong, Andrew T; LaPinska, Melissa Phillips; Yoo, Jin S; Pauli, Eric M; Kroh, Matthew

2018-03-01

Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro ® Hybrid Hernia Repair Device) for VIH repair. This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests. In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m 2 , and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm 2 . Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively. Zenapro ® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate are acceptable. This hybrid mesh represents a novel option for reinforcement during VIH repair.

[Abdominal traumatic evisceration: reconstruction abdominal wall with biologic mesh and negative pressure therapy].

PubMed

Jiménez Gómez, M; Betancor Rivera, N; Lima Sánchez, J; Hernández Hernández, J R

2016-04-10

Abdominal traumatic evisceration as a result of high energy trauma is uncommon. Once repaired the possible internal damage, an abdominal wall defect of high complexity may exist, whose reconstruction represents a surgical challenge. Politraumatized male with important abdominal muculocutaneous avulsion and evisceration. After initial repair, the patient developed a big eventration in which we use a porcine dermis-derived mesh (Permacol TM ), a safe and effective alternative in abdominal wall repair, thanks to its seamless integration with other tissues, even when exposed. Negative pressure therapy has been used for the management of wound complications after surgical implantation of PermacolTM mesh. We describe our experience with the use of PermacolTM mesh and negative pressure therapy to aid the wound closure after skin necrosis and exposed mesh.

Intra-oral soft tissue expansion and volume stability of onlay bone grafts.

PubMed

Abrahamsson, Peter

2011-01-01

Insufficient regeneration of missing bone and soft-tissue may present aesthetic or functional problems in patients indicated for dental implant surgery. Several techniques such as bone grafts, bone substitutes and guided tissue regeneration (GTR) have been described to rebuild a compromised alveolar ridge. Adequate soft-tissue coverage of grafted bone and titanium-mesh is important to avoid exposure which may result in loss of the bone graft. The general aim of this thesis was to evaluate use of an osmotic tissue expander for expanding intra-oral soft tissue--creating a surplus of soft tissue-- in preparation for onlay bone grafting. An experimental rabbit model was used in studies (I), (II) and (III). In (I) an osmotic soft-tissue expander was placed bilaterally on the lateral wall of the mandible via an extra-oral approach. After two weeks of expansion the rabbits were killed and specimens were collected for histology. No inflammatory reaction and no resorbtion of the cortical bone occured. The periosteum was expanded and new bone formation was seen in the edges of the expander. In (II) and (III) the expander was placed under the periosteum in the same way as in (I): bilaterally in 13 rabbits in (II) and unilaterally in 11 rabbits in (III). After two weeks of expansion the expander was identified and removed. In (II) particulated bone was placed at the recipient site protected by a titanium mesh in one site and a bio-resorbable mesh on the other site. In (III), DBBM particles and bone particles collected from the lateral border of the mandible separated by a collagen membrane was placed at the recipient site. The graft was protected by a pre-bent titanium mesh covered by a collagen membrane. After a healing period of 3 months specimens were collected for histological and SEM examination. New bone was growing in direct contact with the titanium mesh and bio resorbable mesh. The newly formed bone had the same calcium content as the mature bone in the base of the mandible. In the clinical study (IV) 20 patients were consecutively recruited and randomised into two groups. The experimental group (ten patients) had an osmotic soft tissue expander implanted. After two weeks of expansion the expander was removed and a particulated bone graft protected by a titanium mesh and a collagen membrane was fixed to the recipient site. Titanium implants were installed after a healing period of 6 months. The patients in the reference group had a bone block grafted from the anterior ramus fixated to the recipient site with one or two titanium mini screws. Implants were installed after a healing period of 6 months. A three dimensional optical measuring device was used to measure alterations in the soft tissue profile before each surgical procedure. The three-dimensional changes were then analysed on a PC. The results from the clinical study in patients confirmed the results from the experimental rabbit studies. The osmotic tissue expander expanded the soft tissue. Expander perforations of the soft tissue occurred in two patients. The optical measurements demonstrated a positive volume gain after soft tissue expansion and bone grafting. The expanded tissue could be used to cover a bone graft. There still was a risk of mesh exposure, even after soft tissue expansion, which occurred in two patients. In both groups, implants could be installed in the grafted bone in positions that would allow the crowns to fit aesthetically into the dental arch.

Polycaprolactone nanowire surfaces as interfaces for cardiovascular applications

NASA Astrophysics Data System (ADS)

Leszczak, Victoria

Cardiovascular disease is the leading killer of people worldwide. Current treatments include organ transplants, surgery, metabolic products and mechanical/synthetic implants. Of these, mechanical and synthetic implants are the most promising. However, rejection of cardiovascular implants continues to be a problem, eliciting a need for understanding the mechanisms behind tissue-material interaction. Recently, bioartificial implants, consisting of synthetic tissue engineering scaffolds and cells, have shown great promise for cardiovascular repair. An ideal cardiovascular implant surface must be capable of adhering cells and providing appropriate physiological responses while the native tissue integrates with the scaffold. However, the success of these implants is not only dependent on tissue integration but also hemocompatibility (interaction of material with blood components), a property that depends on the surface of the material. A thorough understanding of the interaction of cardiovascular cells and whole blood and its components with the material surface is essential in order to have a successful application which promotes healing as well as native tissue integration and regeneration. The purpose of this research is to study polymeric nanowire surfaces as potential interfaces for cardiovascular applications by investigating cellular response as well as hemocompatibility.

Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology.

PubMed

Fu, Tian-Ming; Hong, Guosong; Viveros, Robert D; Zhou, Tao; Lieber, Charles M

2017-11-21

Implantable electrical probes have led to advances in neuroscience, brain-machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases. Copyright © 2017 the Author(s). Published by PNAS.

Assessment of Synthetic Glue for Mesh Attachment in Laparoscopic Sacrocolpopexy: A Prospective Multicenter Pilot Study.

PubMed

Lamblin, Gery; Dubernard, Gil; de Saint Hilaire, Pierre; Jacquot, Franck; Chabert, Philippe; Chene, Gautier; Golfier, François

2017-01-01

To assess the anatomic efficacy and safety of synthetic glue to fix prosthetic material in laparoscopic sacrocolpopexy. A 1-year follow-up in a prospective multicenter pilot study between November 2013 and November 2014 (Canadian Task Force Classification II-2). An academic urogynecology research hospital. Seventy consecutive patients with Pelvic Organ Prolapse Quantification stage ≥3 anterior and/or medial prolapse underwent laparoscopic sacrocolpopexy. All women underwent laparoscopic sacrocolpopexy with the same standardized technique using a synthetic surgical glue to fix anterior and posterior meshes. Patients were followed up at 1 month and 1 year, with anatomic and functional assessment (Pelvic Floor Distress Inventory-20, Pelvic Floor Impact Questionnaire-7, and Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-12). Anatomic success was defined as 1-year Pelvic Organ Prolapse Quantification stage ≤1. Sixty-six patients were included; the mean age was 56.7 ± 1.2 years. The mean operative time was 145 ± 5 minutes. The mean glue fixation time was less than 2 minutes for both anterior and posterior meshes. The 1-year anatomic success rate was 87.5% in the anterior compartment (Ba at -2.3 cm, p < .0001) and 95.3% in the medial compartment (point C at -6.1 cm, p < .0001). There were no intra- or postoperative complications and no cases of mesh exposure; 5 cases of mesh shrinkage (7.8%) were observed at 1 year. The postoperative urinary stress incontinence rate was 29.7% at 1 year. Eight patients (12.1%) underwent revision surgery with transobturator tape. All quality of life scores showed significant improvement (p < .0001) at 1 year. Synthetic glue attachment of prosthetic material in laparoscopic sacrocolpopexy proved straightforward, safe, time-saving, and effective at 1 year. Prospective randomized studies will be needed to confirm the long-term benefit. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Pitfalls in retromuscular mesh repair for incisional hernia: the importance of the "fatty triangle".

PubMed

Conze, J; Prescher, A; Klinge, U; Saklak, M; Schumpelick, V

2004-08-01

Open retromuscular mesh repair has become a standard procedure in incisional hernia repair. This technique led to a significant decrease of recurrences. Recurrences after this technique typically occur at the upper mesh border and are a result of the technical complexity of reaching the postulated underlay of 5 cm in the region of the linea alba. We performed an anatomical study in human corpses to investigate the abdominal wall with its different structures, with emphasis on the overlap of the mesh under the linea alba. The overlap can be achieved by incision of the posterior lamina of the rectus sheath, on both sides close to the linea alba. The incision opens the preperitoneal space and appears in the shape of a "fatty triangle". The anterior lamina of the rectus sheath above the hernia defect remains intact and facilitates a sufficient thrust bearing for a retromuscular mesh implantation. Knowledge of the anatomy and preparation of the "fatty triangle" enables a mesh positioning according to the principles of retromuscular mesh repair.

Evaluation on Bending Properties of Biomaterial GUM Metal Meshed Plates for Bone Graft Applications

NASA Astrophysics Data System (ADS)

Suzuki, Hiromichi; He, Jianmei

2017-11-01

There are three bone graft methods for bone defects caused by diseases such as cancer and accident injuries: Autogenous bone grafts, Allografts and Artificial bone grafts. In this study, meshed GUM Metal plates with lower elasticity, high strength and high biocompatibility are introduced to solve the over stiffness & weight problems of ready-used metal implants. Basic mesh shapes are designed and applied to GUM Metal plates using 3D CAD modeling tools. Bending properties of prototype meshed GUM Metal plates are evaluated experimentally and analytically. Meshed plate specimens with 180°, 120° and 60° axis-symmetrical types were fabricated for 3-point bending tests. The pseudo bending elastic moduli of meshed plate specimens obtained from 3-point bending test are ranged from 4.22 GPa to 16.07 GPa, within the elasticity range of natural cortical bones from 2.0 GPa to 30.0 GPa. Analytical approach method is validated by comparison with experimental and analytical results for evaluation on bending property of meshed plates.

Microgroove and Collagen-poly(ε-caprolactone) Nanofiber Mesh Coating Improves the Mechanical Stability and Osseointegration of Titanium Implants

PubMed Central

Khandaker, Morshed; Riahinezhad, Shahram; Williams, Wendy R.; Wolf, Roman

2017-01-01

The effect of depositing a collagen (CG)-poly-ε-caprolactone (PCL) nanofiber mesh (NFM) at the microgrooves of titanium (Ti) on the mechanical stability and osseointegration of the implant with bone was investigated using a rabbit model. Three groups of Ti samples were produced: control Ti samples where there were no microgrooves or CG-PCL NFM, groove Ti samples where microgrooves were machined on the circumference of Ti, and groove-NFM Ti samples where CG-PCL NFM was deposited on the machined microgrooves. Each group of Ti samples was implanted in the rabbit femurs for eight weeks. The mechanical stability of the Ti/bone samples were quantified by shear strength from a pullout tension test. Implant osseointegration was evaluated by a histomorphometric analysis of the percentage of bone and connective tissue contact with the implant surface. The bone density around the Ti was measured by micro–computed tomography (μCT) analysis. This study found that the shear strength of groove-NFM Ti/bone samples was significantly higher compared to control and groove Ti/bone samples (p < 0.05) and NFM coating influenced the bone density around Ti samples. In vivo histomorphometric analyses show that bone growth into the Ti surface increased by filling the microgrooves with CG-PCL NFM. The study concludes that a microgroove assisted CG-PCL NFM coating may benefit orthopedic implants. PMID:28608839

Open and Laparo-Endoscopic Repair of Incarcerated Abdominal Wall Hernias by the Use of Biological and Biosynthetic Meshes.

PubMed

Fortelny, René H; Hofmann, Anna; May, Christopher; Köckerling, Ferdinand

2016-01-01

Although recently published guidelines recommend against the use of synthetic non-absorbable materials in cases of potentially contaminated or contaminated surgical fields due to the increased risk of infection (1, 2), the use of bio-prosthetic meshes for abdominal wall or ventral hernia repair is still controversially discussed in such cases. Bio-prosthetic meshes have been recommended due to less susceptibility for infection and the decreased risk of subsequent mesh explantation. The purpose of this review is to elucidate if there are any indications for the use of biological and biosynthetic meshes in incarcerated abdominal wall hernias based on the recently published literature. A literature search of the Medline database using the PubMed search engine, using the keywords returned 486 articles up to June 2015. The full text of 486 articles was assessed and 13 relevant papers were identified including 5 retrospective case cohort studies, 2 case-controlled studies, and 6 case series. The results of Franklin et al. (3-5) included the highest number of biological mesh repairs (Surgisis(®)) by laparoscopic IPOM in infected fields, which demonstrated a very low incidence of infection and recurrence (0.7 and 5.2%). Han et al. (6) reported in his retrospective study, the highest number of treated patients due to incarcerated hernias by open approach using acellular dermal matrix (ADM(®)) with very low rate of infection as well as recurrences (1.6 and 15.9%). Both studies achieved acceptable outcome in a follow-up of at least 3.5 years compared to the use of synthetic mesh in this high-risk population (7). Currently, there is a very limited evidence for the use of biological and biosynthetic meshes in strangulated hernias in either open or laparo-endoscopic repair. Finally, there is an urgent need to start with randomized controlled comparative trials as well as to support registries with data to achieve more knowledge for tailored indication for the use of biological meshes.

Protective constriction of coronary vein grafts with knitted nitinol

PubMed Central

Moodley, Loven; Franz, Thomas; Human, Paul; Wolf, Michael F.; Bezuidenhout, Deon; Scherman, Jacques; Zilla, Peter

2013-01-01

OBJECTIVES Different flow patterns and shear forces were shown to cause significantly more luminal narrowing and neointimal tissue proliferation in coronary than in infrainguinal vein grafts. As constrictive external mesh support of vein grafts led to the complete suppression of intimal hyperplasia (IH) in infrainguinal grafts, we investigated whether mesh constriction is equally effective in the coronary position. METHODS Eighteen senescent Chacma baboons (28.8 ± 3.6 kg) received aorto-coronary bypass grafts to the left anterior descending artery (LAD). Three groups of saphenous vein grafts were compared: untreated controls (CO); fibrin sealant-sprayed controls (CO + FS) and nitinol mesh-constricted grafts (ME + FS). Meshes consisted of pulse-compliant, knitted nitinol (eight needles; 50 μm wire thickness; 3.4 mm resting inner diameter, ID) spray attached to the vein grafts with FS. After 180 days of implantation, luminal dimensions and IH were analysed using post-explant angiography and macroscopic and histological image analysis. RESULTS At implantation, the calibre mismatch between control grafts and the LAD expressed as cross-sectional quotient (Qc) was pronounced [Qc = 0.21 ± 0.07 (CO) and 0.18 ± 0.05 (CO + FS)]. Mesh constriction resulted in a 29 ± 7% reduction of the outer diameter of the vein grafts from 5.23 ± 0.51 to 3.68 ± 0 mm, significantly reducing the calibre discrepancy to a Qc of 0.41 ± 0.17 (P < 0.02). After 6 months of implantation, explant angiography showed distinct luminal irregularities in control grafts (ID difference between widest and narrowest segment 74 ± 45%), while diameter variations were mild in mesh-constricted grafts. In all control grafts, thick neointimal tissue was present [600 ± 63 μm (CO); 627 ± 204 μm (CO + FS)] as opposed to thin, eccentric layers of 249 ± 83 μm in mesh-constricted grafts (ME + FS; P < 0.002). The total wall thickness had increased by 363 ± 39% (P < 0.00001) in CO and 312 ± 61% (P < 0.00001) in CO + FS vs 82 ± 61% in ME + FS (P < 0.007). CONCLUSIONS In a senescent non-human primate model for coronary artery bypass grafts, constrictive, external mesh support of saphenous veins with knitted nitinol prevented focal, irregular graft narrowing and suppressed neointimal tissue proliferation by a factor of 2.5. The lower degree of suppression of IH compared with previous infrainguinal grafts coincided with a lesser reduction of calibre mismatch in the coronary grafts. PMID:23295444

Gas gangrene of the abdominal wall due to late-onset enteric fistula after polyester mesh repair of an incisional hernia.

PubMed

Moussi, A; Daldoul, S; Bourguiba, B; Othmani, D; Zaouche, A

2012-04-01

The occurrence of enteric fistulae after wall repair using a prosthetic mesh is a serious but, fortunately, rare complication. We report the case of a 66-year-old diabetic man who presented with gas gangrene of the abdominal wall due to an intra-abdominal abscess caused by intestinal erosion six years after an incisional hernia repair using a polyester mesh. The aim of this case report is to illustrate the seriousness of enteric fistula after parietal repair using a synthetic material.

Endoscopic Removal of a Nitinol Mesh Stent from the Ureteropelvic Junction after 15 Years

PubMed Central

Smrkolj, Tomaž; Šalinović, Domagoj

2015-01-01

We report a rare case of a patient with a large stone encrusted on a nitinol mesh stent in the ureteropelvic junction. The stent was inserted in the year 2000 after failure of two pyeloplasty procedures performed due to symptomatic ureteropelvic junction stenosis. By combining minimally invasive urinary stone therapies—extracorporeal shock wave lithotripsy, semirigid ureterorenoscopy with laser lithotripsy, and percutaneous nephrolithotomy—it was possible to completely remove the encrusted stone and nitinol mesh stent that was implanted for 15 years, rendering the patient symptom and obstruction free. PMID:26697258

Vaginal Approaches Using Synthetic Mesh to Treat Pelvic Organ Prolapse.

PubMed

Moon, Jei Won; Chae, Hee Dong

2016-02-01

Pelvic organ prolapse (POP) is a very common condition in elderly women. In women with POP, a sacrocolpopexy or a vaginal hysterectomy with anterior and posterior colporrhaphy has long been considered as the gold standard of treatment. However, in recent decades, the tendency to use a vaginal approach with mesh for POP surgery has been increasing. A vaginal approach using mesh has many advantages, such as its being less invasive than an abdominal approach and easier to do than a laparoscopic approach and its having a lower recurrence rate than a traditional approach. However, the advantages of a vaginal approach with mesh for POP surgery must be weighed against the disadvantages. Specific complications that have been reported when using mesh in POP procedures are mesh erosion, dyspareunia, hematomas, urinary incontinence and so on, and evidence supporting the use of transvaginal surgery with mesh is still lacking. Hence, surgeons should understand the details of the surgical pelvic anatomy, the various surgical techniques for POP surgery, including using mesh, and the possible side effects of using mesh.

Geostatistical regularization operators for geophysical inverse problems on irregular meshes

NASA Astrophysics Data System (ADS)

Jordi, C.; Doetsch, J.; Günther, T.; Schmelzbach, C.; Robertsson, J. OA

2018-05-01

Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.

Failure of Synthetic Implants: Strategies and Management.

PubMed

Jang, Yong Ju; Kim, Shin Ae; Alharethy, Sami

2018-06-01

Dorsal augmentation with synthetic implants is the most commonly performed rhinoplasty procedure, especially in the East-Asian region. However, as in all other surgical procedures, complications are inevitable. Complications that need to be managed surgically include displacement, deviation, suboptimal aesthetic outcome, extrusion, inflammation, infection, and changes in skin quality. Most complications can be easily managed with revision surgery. After the removal of the synthetic implant from the nasal dorsum, different dorsal implant materials such as dermofat, alloderm, or fascia-wrapped diced cartilage, conchal cartilage with perichondrial attachment, and costal cartilage are preferred. An irreversible change in the skin/soft tissue envelope poses a challenge that usually requires reconstructive surgery with a local flap. Therefore, early detection and prompt management of the complication are essential for minimizing the severity of the deformity and the complexity of the surgical procedures. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Stiffness and ultimate load of osseointegrated prosthesis fixations in the upper and lower extremity.

PubMed

Welke, Bastian; Hurschler, Christof; Föller, Marie; Schwarze, Michael; Calliess, Tilman

2013-07-11

Techniques for the skeletal attachment of amputation-prostheses have been developed over recent decades. This type of attachment has only been performed on a small number of patients. It poses various potential advantages compared to conventional treatment with a socket, but is also associated with an increased risk of bone or implant-bone interface fracture in the case of a fall. We therefore investigated the bending stiffness and ultimate bending moment of such devices implanted in human and synthetic bones. Eight human specimens and 16 synthetic models of the proximal femora were implanted with lower extremity prostheses and eight human specimens and six synthetic humeri were implanted with upper extremity prostheses. They were dissected according to typical amputation levels and underwent loading in a material testing machine in a four-point bending setup. Bending stiffness, ultimate bending moment and fracture modes were determined in a load to failure experiment. Additionally, axial pull-out was performed on eight synthetic specimens of the lower extremity. Maximum bending moment of the synthetic femora was 160.6±27.5 Nm, the flexural rigidity of the synthetic femora was 189.0±22.6 Nm2. Maximum bending moment of the human femora was 100.4±38.5 Nm, and the flexural rigidity was 137.8±29.4 Nm2. The maximum bending moment of the six synthetic humeri was 104.9±19.0 Nm, and the flexural rigidity was 63.7±3.6 Nm2. For the human humeri the maximum bending moment was 36.7±11.0 Nm, and the flexural rigidity at was 43.7±10.5 Nm2. The maximum pull-out force for the eight synthetic femora was 3571±919 N. Significant differences were found between human and synthetic specimens of the lower and upper extremity regarding maximum bending moment, bending displacement and flexural rigidity. The results of this study are relevant with respect to previous finding regarding the load at the interfaces of osseointegrated prosthesis fixation devices and are crucial for the development of safety devices intended to protect the bone-implant interface from damaging loadings.

Stiffness and ultimate load of osseointegrated prosthesis fixations in the upper and lower extremity

PubMed Central

2013-01-01

Background Techniques for the skeletal attachment of amputation-prostheses have been developed over recent decades. This type of attachment has only been performed on a small number of patients. It poses various potential advantages compared to conventional treatment with a socket, but is also associated with an increased risk of bone or implant-bone interface fracture in the case of a fall. We therefore investigated the bending stiffness and ultimate bending moment of such devices implanted in human and synthetic bones. Methods Eight human specimens and 16 synthetic models of the proximal femora were implanted with lower extremity prostheses and eight human specimens and six synthetic humeri were implanted with upper extremity prostheses. They were dissected according to typical amputation levels and underwent loading in a material testing machine in a four-point bending setup. Bending stiffness, ultimate bending moment and fracture modes were determined in a load to failure experiment. Additionally, axial pull-out was performed on eight synthetic specimens of the lower extremity. Results Maximum bending moment of the synthetic femora was 160.6±27.5 Nm, the flexural rigidity of the synthetic femora was 189.0±22.6 Nm2. Maximum bending moment of the human femora was 100.4±38.5 Nm, and the flexural rigidity was 137.8±29.4 Nm2. The maximum bending moment of the six synthetic humeri was 104.9±19.0 Nm, and the flexural rigidity was 63.7±3.6 Nm2. For the human humeri the maximum bending moment was 36.7±11.0 Nm, and the flexural rigidity at was 43.7±10.5 Nm2. The maximum pull-out force for the eight synthetic femora was 3571±919 N. Conclusion Significant differences were found between human and synthetic specimens of the lower and upper extremity regarding maximum bending moment, bending displacement and flexural rigidity. The results of this study are relevant with respect to previous finding regarding the load at the interfaces of osseointegrated prosthesis fixation devices and are crucial for the development of safety devices intended to protect the bone-implant interface from damaging loadings. PMID:23844992

Low Profile Mesh Plating for Patella Fractures: Video of a Novel Surgical Technique.

PubMed

Verbeek, Diederik O; Hickerson, Lindsay E; Warner, Stephen J; Helfet, David L; Lorich, Dean G

2016-08-01

Patella fractures can be challenging to treat particularly in the presence of inferior pole comminution. In this video we present a novel surgical technique for the treatment of patella fractures using a small fragment low profile mesh plate. Key points are the surgical exposure with direct visualization of the articular reduction, the preparation of the mesh plate to accommodate patellar anatomy and the augmentation of the construct using Krackow sutures to address inferior pole comminution. Low profile mesh plating allows for multiplanar fixation of patella fractures while avoiding implant and fixation problems related to tension band fixation. Our early experience with this technique is encouraging and it appears that this technique is useful for the treatment of the majority of patella fractures.

[Bone defect replacement under conditions of transosseous osteosynthesis and titanium nickelide implant application].

PubMed

Ir'ianov, Iu M; Ir'ianova, T Iu

2012-01-01

In the experiment conducted on 30 Wistar rats, the peculiarities of tibial bone defect replacement under conditions of transosseous osteosynthesis and implantation of titanium nickelide mesh structures were studied using the methods of scanning electron microscopy and x-ray electron probe microanalysis. It was demonstrated that implant osseointegration occured 7 days after surgery, and after 30 days the defect was replaced with bone tissue by the type of primary bone wound healing, thus the organotypical remodeling of regenerated bone took place.

Induction of human umbilical cord mesenchymal stem cells into tissue-forming cells in a murine model: implications for pelvic floor reconstruction.

PubMed

Ding, Jing; Han, Qin; Deng, Mou; Song, Xiao-Chen; Chen, Chun; Ai, Fang-Fang; Zhu, Lan; Zhao, Robert Chun-Hua

2018-06-01

HUMSCs were isolated, differentiated and characterized in vitro. Both HUMSCs and smooth muscle cells differentiated from HUMSCs were used to fabricate tissue-engineered fascia equivalents. Forty-eight mature female Sprague Dawley rats were randomly assigned to four groups: group A (GynemeshTMPS, n = 12), group B (GynemeshTMPS + HUMSCs; n = 12), group C (GynemeshTMPS + smooth muscle cells differentiated from HUMSCs; n = 12) and group D (GynemeshTMPS + HUMSCs + smooth muscle cells differentiated from HUMSCs; n = 12). The posterior vaginal wall was incised from the introitus and the mesh was then implanted. Three implants of each type were tested at 1, 4, 8 and 12 weeks. Fibrotic remodeling, inflammation, vascularization and tissue regeneration were histologically assessed. The levels of type I and type III collagen were determined. There was no difference in fibrotic remodeling between cell-seeded and unseeded meshes at any time (p > 0.05). At 12 weeks, there did not appear to be fewer inflammatory cells around the filament bundles in the mesh with cells compared with the mesh alone (P > 0.05). Group D showed a trend toward better vascularization at 12 weeks compared with group A (P < 0.05). Twelve weeks after implantation, a thin layer of new tissue growth covered the unseeded scaffold and a thicker layer covered the cell-seeded scaffold (P < 0.05). No significant difference in the ratio of collagen type I/III could be detected among the different groups after 12 weeks (P > 0.05). HUMSCs with differentiated smooth muscle cells might have a potential role in fascia tissue engineering to repair POP in the future.

Synthetic resorbable scaffolds for the treatment of isolated patellofemoral cartilage defects in young patients: magnetic resonance imaging and clinical evaluation.

PubMed

Joshi, Nayana; Reverte-Vinaixa, Mercè; Díaz-Ferreiro, Eugenio Wenceslao; Domínguez-Oronoz, Rosa

2012-06-01

Surgical management of patellar cartilage defects remains controversial. The ideal technique to regenerate hyaline cartilage is not yet defined. However, a synthetic resorbable osteochondral scaffold plug (TruFit CB) seems to offer a treatment option with good results at short-term follow-up, at least in the condylar setting. A synthetic implant provides a simple and efficacious means of treating the cartilage defects of the patellofemoral joint in young patients. Case series; Level of evidence, 4. A study was designed to evaluate prospectively short- and medium-term results in patients with osteochondral patellar defects treated with synthetic reabsorbable scaffolds. Patient outcome scores (Short Form 36 [SF-36] and Knee injury and Osteoarthritis Outcome Score [KOOS]), demographics, prior surgeries, and data from a physical examination were collected at baseline (before implantation) and at 6, 12, and 24 months after surgery. Defect characteristics were collected during implantation. Diagnosis and monitoring were performed by magnetic resonance imaging. Ten patients with a mean age of 33.3 years (range, 16-49 years) were evaluated prospectively at 24 months' follow-up. The number of plugs used for each patient ranged from 1 to 4. At 1-year follow-up, the results were satisfactory in 8 of 10 patients, and poor in 2, according to clinical assessment (KOOS, visual analog scale, and SF-36). At 18 months of follow-up, all patients except one complained of pain and knee swelling. Reoperation rate for implant failure at final follow-up was 70%. Magnetic resonance imaging at final follow-up showed a cylindrical cavity of fibrous tissue instead of subchondral bone restoration. A synthetic implant can improve symptoms and joint function, especially for small lesions, only for a short period of time. However, 2 years of monitoring has shown its failure in restoring the subchondral bone despite the formation of predominant hyaline cartilage from synthetic resorbable scaffolds. Under current conditions and according to our experience, we do not recommend TruFit synthetic implants for osteochondral patellar defects in active patients.

In vivo analysis of biocompatibility and vascularization of the synthetic bone grafting substitute NanoBone.

PubMed

Abshagen, K; Schrodi, I; Gerber, T; Vollmar, B

2009-11-01

One of the major challenges in the application of bone substitutes is adequate vascularization and biocompatibility of the implant. Thus, the temporal course of neovascularization and the microvascular inflammatory response of implants of NanoBone (fully synthetic nanocrystalline bone grafting material) were studied in vivo by using the mouse dorsal skinfold chamber model. Angiogenesis, microhemodynamics, and leukocyte-endothelial cell interaction were analyzed repetitively after implantation in the center and in the border zone of the implant up to 15 days. Both NanoBone granules and plates exhibited high biocompatibility comparable to that of cancellous bone, as indicated by a lack of venular leukocyte activation after implantation. In both synthetic NanoBone groups, signs of angiogenesis could be observed even at day 5 after implantation, whereas granules showed higher functional vessel density compared with NanoBone plates. The angiogenic response of the cancellous bone was markedly accelerated in the center of the implant tissue. Histologically, implant tissue showed an ingrowth of vascularized fibrous tissue into the material combined with an increased number of foreign-body giant cells. In conclusion, NanoBone, particularly in granular form, showed high biocompatibility and high angiogenic response, thus improving the healing of bone defects. Our results underline that, beside the composition and nanostructure, the macrostructure is also of importance for the incorporation of the biomaterial by the host tissue. (c) 2008 Wiley Periodicals, Inc.

A Mini-review on the Effect of Mini-implants on Contemporary Orthodontic Science

PubMed Central

Nosouhian, Saeid; Rismanchian, Mansour; Sabzian, Roya; Shadmehr, Elham; Badrian, Hamid; Davoudi, Amin

2015-01-01

The purpose of this literature review was to screen the valuable published articles regarding to the impacts of mini-implants on orthodontic science, briefly. The searching category was performed on the Pubmed using MeSH words such as “dental (mini) implants, orthodontic anchorage procedures, and orthodontic appliances.” After preliminary sketch, they were grouped as follow: Those evaluating (a) common appliances for providing orthodontic anchorage, (b) biomechanical details of mini-implants and their insertion, (c) clinical application of mini-implants for orthognathic treatments, (d) limitations and possible complications. In conclusion, mini-implant evolved the orthodontic treatment plans and compromised the required orthognathic surgery. Malocclusion treatment and pure orthodontic or orthopedic movements in the three-dimensions have become recently possible by using mini-implant to provide skeletal anchorage. PMID:26225113

Highly Symmetric and Congruently Tiled Meshes for Shells and Domes

PubMed Central

Rasheed, Muhibur; Bajaj, Chandrajit

2016-01-01

We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable. PMID:27563368

Multicenter, Prospective, Longitudinal Study of the Recurrence, Surgical Site Infection, and Quality of Life After Contaminated Ventral Hernia Repair Using Biosynthetic Absorbable Mesh

PubMed Central

Rosen, Michael J.; Bauer, Joel J.; Harmaty, Marco; Carbonell, Alfredo M.; Cobb, William S.; Matthews, Brent; Goldblatt, Matthew I.; Selzer, Don J.; Poulose, Benjamin K.; Hansson, Bibi M. E.; Rosman, Camiel; Chao, James J.; Jacobsen, Garth R.

2017-01-01

Objective: The aim of the study was to evaluate biosynthetic absorbable mesh in single-staged contaminated (Centers for Disease Control class II and III) ventral hernia (CVH) repair over 24 months. Background: CVH has an increased risk of postoperative infection. CVH repair with synthetic or biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. Methods: Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm2 had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. Results: Patients had a mean age of 58 years, body mass index of 28 kg/m2, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ≤ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). Conclusions: In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations. PMID:28009747

Mechanical response of the herniated human abdomen to the placement of different prostheses.

PubMed

Hernández-Gascón, Belén; Peña, Estefanía; Grasa, Jorge; Pascual, Gemma; Bellón, Juan M; Calvo, Begoña

2013-05-01

This paper describes a method designed to model the repaired herniated human abdomen just after surgery and examine its static mechanical response to the maximum intra-abdominal pressure provoked by a physiological movement (standing cough). The model is based on the real geometry of the human abdomen bearing a large incisional hernia with several anatomical structures differentiated by MRI. To analyze the outcome of hernia repair, the surgical procedure was simulated by modeling a prosthesis placed over the hernia. Three surgical meshes with different mechanical properties were considered: an isotropic heavy-weight mesh (Surgipro®), a slightly anisotropic light-weight mesh (Optilene®), and a highly anisotropic medium-weight mesh (Infinit®). Our findings confirm that anisotropic implants need to be positioned such that the most compliant axis of the mesh coincides with the craneo-caudal direction of the body.

Use of negative pressure wound therapy in the management of infected abdominal wounds containing mesh: an analysis of outcomes.

PubMed

Baharestani, Mona Mylene; Gabriel, Allen

2011-04-01

The purpose of this study was to examine the clinical outcomes of negative pressure wound therapy (NPWT) using reticulated open-cell foam (ROCF) in the adjunctive management of abdominal wounds with exposed and known infected synthetic mesh. A non randomised, retrospective review of medical records for 21 consecutive patients with infected abdominal wounds treated with NPWT was conducted. All abdominal wounds contained exposed synthetic mesh [composite, polypropylene (PP), or knitted polyglactin 910 (PG) mesh]. Demographic and bacteriological data, wound history, pre-NPWT and comparative post-NPWT, operative procedures and complications, hospital length of stay (LOS) and wound healing outcomes were all analysed. Primary endpoints measured were (1) hospital LOS prior to initiation of NPWT, (2) total time on NPWT, (3) hospital LOS from NPWT initiation to discharge and (4) wound closure status at discharge. A total of 21 patients with abdominal wounds with exposed, infected mesh were treated with NPWT. Aetiology of the wounds was ventral hernia repair (n = 11) and acute abdominal wall defect (n = 10). Prior to NPWT initiation, the mean hospital LOS for the composite, PP and PG meshes were 76 days (range: 21-171 days), 51 days (range: 32-62 days) and 19 days (range: 12-39 days), respectively. The mean hospital LOS following initiation of NPWT for wounds with exposed composite, PP and PG mesh were 28, 31 and 32 days, respectively. Eighteen of the 21 wounds (86%) reached full closure after a mean time of 26 days of NPWT and a mean hospital LOS of 30 days postinitiation of NPWT. Three wounds, all with composite mesh left in situ, did not reach full closure, although all exhibited decreased wound dimensions, granulating beds and decreased surface area exposure of mesh. During NPWT/ROCF, one hypoalbuminemic patient with exposed PP mesh developed an enterocutaneous fistula over a prior enterotomy site. This patient subsequently underwent total mesh extraction, takedown of the fistula and PP mesh replacement followed by reinstitution of NPWT and flap closure. In addition to appropriate systemic antibiotics and nutritional optimisation, the adjunctive use of NPWT resulted in successful closure of 86% of infected abdominal wounds with exposed prosthetic mesh. Patient hospital LOS (except those with PG mesh), operative procedures and readmissions were decreased during NPWT compared with treatment prior to NPWT. Future multi-site prospective, controlled studies would provide a strong evidence base from which treatment decisions could be made in the management of these challenging and costly cases. © 2010 The Authors. © 2010 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

A promising new device for the prevention of parastomal hernia.

PubMed

Hoffmann, Henry; Oertli, Daniel; Soysal, Savas; Zingg, Urs; Hahnloser, Dieter; Kirchhoff, Philipp

2015-06-01

Parastomal hernia (PSH) is the most frequent long-term stoma complication with serious negative effects on quality of life. Surgical revision is often required and has a substantial morbidity and recurrence rate. The development of PSH requires revisional surgery with a substantial perioperative morbidity and high failure rate in the long-term follow-up. Prophylactic parastomal mesh insertion during stoma creation has the potential to reduce the rate of PSH, but carries the risk of early and late mesh-related complications such as infection, fibrosis, mesh shrinkage, and/or bowel erosion. We developed a new stomaplasty ring (KORING), which is easy to implant, avoids potential mesh-related complications, and has a high potential of long-term prevention of PSH. Here we describe the technique and the first use. © The Author(s) 2014.

[Treatment of enophthalmos after severe malar-maxillary complex fracture with titanium mesh and high density polyethylene (Medpor)].

PubMed

Zhao, Yan-feng; Lu, Ping; Zhou, Xiao-nan; Qu, Chang-feng

2010-03-01

To study the surgical management of enophthalmos after severe malar maxillary complex fracture. The X-ray and CT examination were performed before operation to diagnose the orbital fracture and intraorbital tissue displacement. The fractured orbital rim was repositioned intraoperatively, followed by implantation of shaped titanium mesh to rebuild the orbital floor. The Medpor was inserted above the titanium mesh to correct the enophthalmos. From Sept. 2007 to Jan. 2009, 6 cases of enophthalmos after severe malar-maxillary complex fracture were treated. The enophthalmos was corrected or improved obviously in all the patients. The enophthalmos after severe malar-maxillary complex fracture can be corrected or obviously improved. Shaped titanium mesh can be used to rebuild the orbital floor with the Medpor to reconstruct the intraorbital tissue volume.

Solute diffusion through fibrotic tissue formed around protective cage system for implantable devices.

PubMed

Prihandana, Gunawan Setia; Ito, Hikaru; Tanimura, Kohei; Yagi, Hiroshi; Hori, Yuki; Soykan, Orhan; Sudo, Ryo; Miki, Norihisa

2015-08-01

This article presents the concept of an implantable cage system that can house and protect implanted biomedical sensing and therapeutic devices in the body. Cylinder-shaped cages made of porous polyvinyl alcohol (PVA) sheets with an 80-µm pore size and/or stainless steel meshes with 0.54-mm openings were implanted subcutaneously in the dorsal region of rats for 5 weeks. Analysis of the explanted cages showed the formation of fibrosis tissue around the cages. PVA cages had fibrotic tissue growing mostly along the outer surface of cages, while stainless steel cages had fibrotic tissue growing into the inside surface of the cage structure, due to the larger porosity of the stainless steel meshes. As the detection of target molecules with short time lags for biosensors and mass transport with low diffusion resistance into and out of certain therapeutic devices are critical for the success of such devices, we examined whether the fibrous tissue formed around the cages were permeable to molecules of our interest. For that purpose, bath diffusion and microfluidic chamber diffusion experiments using solutions containing the target molecules were performed. Diffusion of sodium, potassium and urea through the fibrosis tissue was confirmed, thus suggesting the potential of these cylindrical cages surrounded by fibrosis tissue to successfully encase implantable sensors and therapeutic apparatus. © 2014 Wiley Periodicals, Inc.

Urogynecologic Surgical Mesh Implants

MedlinePlus

... FDA collected samples during the inspections, and reviewed mechanical performance testing and sterility testing of the final ... characterization of the polypropylene resin, and biocompatibility and mechanical performance testing on the final product. The FDA ...

Hernia Surgical Mesh Implants

MedlinePlus

... Surgical Clinics of North America; 83(5):1045-51, v-vi. 2 . http://www.facs.org/public_ ... FDA Contact FDA Browse by Product Area Product Areas back Food Drugs Medical Devices Radiation-Emitting Products ...

Plastic efficiency of different implants used for repair of soft and bone tissue defects.

PubMed

Iriyanov, Yu M; Chernov, V F; Radchenko, S A; Chernov, A V

2013-08-01

The results of clinical and experimental morphological studies of regenerates forming after replacement of large defects of the abdominal wall and tibia with implants from different materials (polytetrafluoroethylene, reperene, prolene, titanium, and titanium nickelide) are analyzed. Study of the regenerate histology and fibroarchitectonics has shown good prospects of mesh constructions from titanium nickelide for effective surgical repair of these defects. The use of this implant seems to be theoretically well-based and promising, particularly under conditions of suppurative infection and low individual reparative regenerative potential.

Mind-controlled transgene expression by a wireless-powered optogenetic designer cell implant.

PubMed

Folcher, Marc; Oesterle, Sabine; Zwicky, Katharina; Thekkottil, Thushara; Heymoz, Julie; Hohmann, Muriel; Christen, Matthias; Daoud El-Baba, Marie; Buchmann, Peter; Fussenegger, Martin

2014-11-11

Synthetic devices for traceless remote control of gene expression may provide new treatment opportunities in future gene- and cell-based therapies. Here we report the design of a synthetic mind-controlled gene switch that enables human brain activities and mental states to wirelessly programme the transgene expression in human cells. An electroencephalography (EEG)-based brain-computer interface (BCI) processing mental state-specific brain waves programs an inductively linked wireless-powered optogenetic implant containing designer cells engineered for near-infrared (NIR) light-adjustable expression of the human glycoprotein SEAP (secreted alkaline phosphatase). The synthetic optogenetic signalling pathway interfacing the BCI with target gene expression consists of an engineered NIR light-activated bacterial diguanylate cyclase (DGCL) producing the orthogonal second messenger cyclic diguanosine monophosphate (c-di-GMP), which triggers the stimulator of interferon genes (STING)-dependent induction of synthetic interferon-β promoters. Humans generating different mental states (biofeedback control, concentration, meditation) can differentially control SEAP production of the designer cells in culture and of subcutaneous wireless-powered optogenetic implants in mice.

Fabrication, pore structure and compressive behavior of anisotropic porous titanium for human trabecular bone implant applications.

PubMed

Li, Fuping; Li, Jinshan; Xu, Guangsheng; Liu, Gejun; Kou, Hongchao; Zhou, Lian

2015-06-01

Porous titanium with average pore size of 100-650 μm and porosity of 30-70% was fabricated by diffusion bonding of titanium meshes. Pore structure was characterized by Micro-CT scan and SEM. Compressive behavior of porous titanium in the out-of-plane direction was studied. The effect of porosity and pore size on the compressive properties was also discussed based on the deformation mode. The results reveal that the fabrication process can control the porosity precisely. The average pore size of porous titanium can be tailored by adjusting the pore size of titanium meshes. The fabricated porous titanium possesses an anisotropic structure with square pores in the in-plane direction and elongated pores in the out-of-plane direction. The compressive Young's modulus and yield stress are in the range of 1-7.5 GPa and 10-110 MPa, respectively. The dominant compressive deformation mode is buckling of mesh wires, but some uncoordinated buckling is present in porous titanium with lower porosity. Relationship between compressive properties and porosity conforms well to the Gibson-Ashby model. The effect of pore size on compressive properties is fundamentally ascribed to the aspect ratio of titanium meshes. Porous titanium with 60-70% porosity has potential for trabecular bone implant applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of infectious complications with synthetic mesh in ventral hernia repair.

PubMed

Brown, Rodger H; Subramanian, Anuradha; Hwang, Cindy S; Chang, Shirong; Awad, Samir S

2013-02-01

Infection can be a devastating complication associated with prosthetic incisional hernia repair. It is unclear whether the type of mesh used affects the risk of infection. A retrospective review was performed of all patients who underwent elective incisional hernia repair with permanent prosthetic mesh between January 1, 2000, and August 1, 2007. A total of 176 patients underwent elective incisional hernia repair with mesh. The overall infection rate with the use of goretex (Flagstaff, AZ, USA) was 12 of 86 (14%) and 2 of 90 (2.2%) in cases in which nongoretex material was used (P = .016). In the goretex group, infection rates were significantly higher in open versus laparoscopic cases (26.5% vs 5.8%, P = .030). Methicillin-resistant Staphylococcus aureus was the most common organism recovered. The risk of mesh infection with the use of goretex was found to be higher than with the use of nongoretex mesh. Laparoscopic placement of goretex reduces this risk of infection. No significant differences in recurrence rates were found. Published by Elsevier Inc.

A synthetic bioactive resorbable graft for predictable implant reconstruction: part one.

PubMed

Valen, Maurice; Ganz, Scott D

2002-01-01

Animal studies were conducted to evaluate the cell response and chemical potentiality of a synthetic bioactive resorbable graft (SBRG) made of nonceramic cluster particulate of low-temperature HA material. The study evaluated bone-bridging of the SBRG particulates in 1-mm wide implant channels of 5 x 8 mm long roughened titanium interface in 6 dogs and compared results to the same implant channels left empty as controls at 6- and 12-week intervals. Resorption rate capacity and cell response were evaluated with an assessment of the chemical characterization of the synthetic nonceramic material next to the titanium implant interfaces. Results of the animal studies were compared with human histologic biopsies of the SBRG for bone quality, density, and bone growth into defect sites concurrent with resorption time of the graft. One human biopsy consisted of a graft mixture of the SBRG and dense bovine-derived HA, compared under the electron microscope, including histology by H and E staining. Part 1 of this paper presents evidence of the predictability and efficacy of the SBRG osteoconductive, particulate chemical potentiality to aid in the regeneration of lost bone anatomy next to titanium implant interfaces. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional quality and density of bone, including anatomical discrepancies, which can aid in the diagnosis and treatment planning for grafting procedures. When teeth are extracted, the surrounding bone and soft tissue are challenged as a result of the natural resorptive process. The diminished structural foundation for prosthetic reconstruction, with or without implants, can be compromised. A synthetic bioactive resorbable graft material having osteoconductive biochemical and biomechanical qualities similar to the host bone provides the means to improve compromised bone topography for ridge preservation, ridge augmentation, or to enhance the bony site for implant placement and subsequent prosthetic rehabilitation. Part two of this paper will demonstrate clinical applications of the SBRG material for purposes of implant placement and prosthetic reconstruction.

Custom-made titanium devices as membranes for bone augmentation in implant treatment: Clinical application and the comparison with conventional titanium mesh.

PubMed

Sumida, Tomoki; Otawa, Naruto; Kamata, Y U; Kamakura, Satoshi; Mtsushita, Tomiharu; Kitagaki, Hisashi; Mori, Shigeo; Sasaki, Kiyoyuki; Fujibayashi, Shunsuke; Takemoto, Mitsuru; Yamaguchi, Atsushi; Sohmura, Taiji; Nakamura, Takashi; Mori, Yoshihide

2015-12-01

Development of new custom-made devices to reconstruct alveolar bone for implantation, and comparison with conventional methods were the goals of this study. Using a computer-aided design technique, three-dimensional images were constructed. From these data, custom-made devices were produced by a selective laser melting method with pure titanium. Clinical trials also have been conducted with 26 participants who needed bone reconstruction before implantation; they were divided into 2 groups with 13 patients each. The first group uses custom-made devices; the other uses commercial titanium meshes that need to bend during operation. Some clinical aspects are evaluated after the trial. The custom-made devices can be produced closely by following the data precisely. Devices are fit for bone defect site. Moreover, the operation time of the custom-made group (75.4 ± 11.6 min) was significantly shorter than that of the conventional group (111.9 ± 17.8 min) (p < 0.01). Mucosal rupture occurs, without significant difference (p = 0.27), in a patient in the custom-made without severe infection (7.7%), and 3 in conventional (23.1%), respectively. The retaining screw is significantly fewer in the custom-made group than commercial mesh group (p < 0.01). These results indicate that our novel protocol could be simple and safe for providing powerful support for guided bone regeneration. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Combined in vivo and ex vivo analysis of mesh mechanics in a porcine hernia model.

PubMed

Kahan, Lindsey G; Lake, Spencer P; McAllister, Jared M; Tan, Wen Hui; Yu, Jennifer; Thompson, Dominic; Brunt, L Michael; Blatnik, Jeffrey A

2018-02-01

Hernia meshes exhibit variability in mechanical properties, and their mechanical match to tissue has not been comprehensively studied. We used an innovative imaging model of in vivo strain tracking and ex vivo mechanical analysis to assess effects of mesh properties on repaired abdominal walls in a porcine model. We hypothesized that meshes with dissimilar mechanical properties compared to native tissue would alter abdominal wall mechanics more than better-matched meshes. Seven mini-pigs underwent ventral hernia creation and subsequent open repair with one of two heavyweight polypropylene meshes. Following mesh implantation with attached radio-opaque beads, fluoroscopic images were taken at insufflation pressures from 5 to 30 mmHg on postoperative days 0, 7, and 28. At 28 days, animals were euthanized and ex vivo mechanical testing performed on full-thickness samples across repaired abdominal walls. Testing was conducted on 13 mini-pig controls, and on meshes separately. Stiffness and anisotropy (the ratio of stiffness in the transverse versus craniocaudal directions) were assessed. 3D reconstructions of repaired abdominal walls showed stretch patterns. As pressure increased, both meshes expanded, with no differences between groups. Over time, meshes contracted 17.65% (Mesh A) and 0.12% (Mesh B; p = 0.06). Mesh mechanics showed that Mesh A deviated from anisotropic native tissue more than Mesh B. Compared to native tissue, Mesh A was stiffer both transversely and craniocaudally. Explanted repaired abdominal walls of both treatment groups were stiffer than native tissue. Repaired tissue became less anisotropic over time, as mesh properties prevailed over native abdominal wall properties. This technique assessed 3D stretch at the mesh level in vivo in a porcine model. While the abdominal wall expanded, mesh-ingrown areas contracted, potentially indicating stresses at mesh edges. Ex vivo mechanics demonstrate that repaired tissue adopts mesh properties, suggesting that a better-matched mesh could reduce changes to abdominal wall mechanics.

Current aspects in reconstructive surgery for nasal cavity and paranasal sinus cancer

NASA Astrophysics Data System (ADS)

Shtin, V. I.; Novikov, V. A.; Gjunter, V. E.; Choinzonov, E. L.; Ryabova, A. I.; Sirkashev, V. A.; Surkova, P. V.; Vasilev, R. V.; Menkova, E. N.

2017-09-01

Tumors of the nasal cavity and paranasal sinuses present a challenge to treat them. A combination of surgery and radiation therapy can improve treatment outcomes in 49-56% [1, 2] of the patients with locally advanced nasal cavity and paranasal sinus cancer. The midface reconstruction poses a formidable challenge to the reconstructive surgeon due to the region's complex skeletal and soft-tissue anatomy. The rehabilitation program including the reconstruction of the resected orbital walls using the porous and mesh implants from titanium nickelid (TiNi) was developed at the Cancer Research institute jointly with the Research Institute of Medical Materials. The technique was proven effective, allowing the natural position of the eye and visual function to be preserved in 90% [1-3] of the patients. A long period of reparative processes and risk of developing inflammation in the implant area, as well as the need to decrease length of surgery, contributed to the development of a novel approach to repairing the midface bone structures using the implant based on the microporous wire and TiNi mesh. Eighteen patients with nasal cavity and paranasal sinus cancer were treated using the combined thin implants. The novel technique allowed the time of the implant installation to be reduced to 5-10 min. The structure of the implant contributed to prevention of inflammatory processes in 97% [1, 2] of cases. Thus, the natural position of the eyeball and visual function were preserved in 100% [1, 3, 4] of patients. The use of the TiNi implants in reconstructive surgery for patients with nasal cavity and paranasal sinus cancer led to reduced time of surgery and rehabilitation, increased level of social adaptation of patients and improved cosmetic and functional results.

Secondary barrier construction for vessels carrying spherical low temperature liquefied gas storage tanks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okamoto, T.; Nishimoto, T.; Sawada, K.

1978-05-16

To simplify and thus reduce the cost of the secondary barrier for spherical LNG storage tanks onboard ocean-transport vessels, Japan's Hitachi Shipbuilding and Engineering Co., Ltd., has developed a new secondary-containment system that allows easy installation directly on the cargo hold's bottom plate beneath the spherical tank. The new system comprises at least two layers of rigid-foam synthetic resin sprayed on the hold plates and covered by a layer of glass mesh and adhesive. Alternatively, the layers of synthetic resin, glass mesh, and adhesive are applied to plywood attached to the hold plates by joists, thus forming an air spacemore » between the secondary barrier and the hold plates. Where the hold plates have a multisurface construction, (1) laminated rigid urethane foam blocks are butted end-to-end and are bonded to each other and to the plywood sheets at the corners between adjacent hold plates, (2) the spray-formed layers are applied between the blocks, and (3) the entire assembly is covered by a protective layer of glass mesh and adhesive.« less

Wound healing process and mediators: Implications for modulations for hernia repair and mesh integration.

PubMed

Sadava, Emmanuel E; Krpata, David M; Gao, Yue; Rosen, Michael J; Novitsky, Yuri W

2014-01-01

In recent years, major advances have been accomplished in abdominal wall reconstruction. Introduction of newer prostheses have improved outcomes, but elimination of mesh-related morbidity is still an elusive issue. It is believed that host foreign body reaction to prosthesis plays an important role in the biology of these complications, so understanding of the molecular mechanisms behind mesh-tissue interactions may be a key for upcoming therapies. It appears that increasing biocompatibility of both synthetic prosthesis and biologic scaffolds might be the main avenues to achieve better outcomes. This manuscript provides an overview of major effectors of wound healing with particular emphasis on how their modulation might improve outcomes in tissue remodeling and mesh integration. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

Early biocompatibility of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral hernia repair.

PubMed

Melman, L; Jenkins, E D; Hamilton, N A; Bender, L C; Brodt, M D; Deeken, C R; Greco, S C; Frisella, M M; Matthews, B D

2011-04-01

Biologic meshes have unique physical properties as a result of manufacturing techniques such as decellularization, crosslinking, and sterilization. The purpose of this study is to directly compare the biocompatibility profiles of five different biologic meshes, AlloDerm(®) (non-crosslinked human dermal matrix), PeriGuard(®) (crosslinked bovine pericardium), Permacol(®) (crosslinked porcine dermal matrix), Strattice(®) (non-crosslinked porcine dermal matrix), and Veritas(®) (non-crosslinked bovine pericardium), using a porcine model of ventral hernia repair. Full-thickness fascial defects were created in 20 Yucatan minipigs and repaired with the retromuscular placement of biologic mesh 3 weeks later. Animals were euthanized at 1 month and the repair sites were subjected to tensile testing and histologic analysis. Samples of unimplanted (de novo) meshes and native porcine abdominal wall were also analyzed for their mechanical properties. There were no significant differences in the biomechanical characteristics between any of the mesh-repaired sites at 1 month postimplantation or between the native porcine abdominal wall without implanted mesh and the mesh-repaired sites (P > 0.05 for all comparisons). Histologically, non-crosslinked materials exhibited greater cellular infiltration, extracellular matrix (ECM) deposition, and neovascularization compared to crosslinked meshes. While crosslinking differentiates biologic meshes with regard to cellular infiltration, ECM deposition, scaffold degradation, and neovascularization, the integrity and strength of the repair site at 1 month is not significantly impacted by crosslinking or by the de novo strength/stiffness of the mesh.

Suture, synthetic, or biologic in contaminated ventral hernia repair.

PubMed

Bondre, Ioana L; Holihan, Julie L; Askenasy, Erik P; Greenberg, Jacob A; Keith, Jerrod N; Martindale, Robert G; Roth, J Scott; Liang, Mike K

2016-02-01

Data are lacking to support the choice between suture, synthetic mesh, or biologic matrix in contaminated ventral hernia repair (VHR). We hypothesize that in contaminated VHR, suture repair is associated with the lowest rate of surgical site infection (SSI). A multicenter database of all open VHR performed at from 2010-2011 was reviewed. All patients with follow-up of 1 mo and longer were included. The primary outcome was SSI as defined by the Centers for Disease Control and Prevention. The secondary outcome was hernia recurrence (assessed clinically or radiographically). Multivariate analysis (stepwise regression for SSI and Cox proportional hazard model for recurrence) was performed. A total of 761 VHR were reviewed for a median (range) follow-up of 15 (1-50) mo: there were 291(38%) suture, 303 (40%) low-density and/or mid-density synthetic mesh, and 167(22%) biologic matrix repair. On univariate analysis, there were differences in the three groups including ethnicity, ASA, body mass index, institution, diabetes, primary versus incisional hernia, wound class, hernia size, prior VHR, fascial release, skin flaps, and acute repair. The unadjusted outcomes for SSI (15.1%; 17.8%; 21.0%; P = 0.280) and recurrence (17.8%; 13.5%; 21.5%; P = 0.074) were not statistically different between groups. On multivariate analysis, biologic matrix was associated with a nonsignificant reduction in both SSI and recurrences, whereas synthetic mesh associated with fewer recurrences compared to suture (hazard ratio = 0.60; P = 0.015) and nonsignificant increase in SSI. Interval estimates favored biologic matrix repair in contaminated VHR; however, these results were not statistically significant. In the absence of higher level evidence, surgeons should carefully balance risk, cost, and benefits in managing contaminated ventral hernia repair. Copyright © 2016 Elsevier Inc. All rights reserved.

Does Attorney Advertising Influence Patient Perceptions of Pelvic Mesh?

PubMed

Tippett, Elizabeth; King, Jesse; Lucent, Vincent; Ephraim, Sonya; Murphy, Miles; Taff, Eileen

2018-01-01

To measure the relative influence of attorney advertising on patient perceptions of pelvic mesh compared with a history of surgery and a first urology visit. A 52-item survey was administered to 170 female patients in 2 urology offices between 2014 and 2016. Multiple survey items were combined to form scales for benefit and risk perceptions of pelvic mesh, perceptions of the advertising, attitudes toward pelvic mesh, and knowledge of pelvic mesh and underlying medical conditions. Data were analyzed using hierarchical linear regression models. Exposure to attorney advertising was quite high; 88% reported seeing a mesh-related attorney advertisement in the last 6 months. Over half of patients reported seeing attorney advertisements more than once per week. A history of prior mesh implant surgery was the strongest predictor of benefit and risk perceptions of pelvic mesh. Exposure to attorney advertising was associated with higher risk perceptions but did not significantly affect perceptions of benefits. Past urologist visits increased perceptions of benefits but had no effect on risk perceptions. Attorney advertising appears to have some influence on risk perceptions, but personal experience and discussions with a urogynecologist or urologist also influence patient perceptions. Implications, limitations, and future research are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Multi-staged repair of contaminated primary and recurrent giant incisional herniae in the same hospital admission: a proposal for a new approach.

PubMed

Siddique, K; Shrestha, A; Basu, S

2014-02-01

Repair of primary and recurrent giant incisional herniae is extremely challenging and more so in the face of surgical field contamination. Literature supports the single- and multi-staged approaches including the use of biological meshes for these difficult patients with their associated benefits and limitations. This is a retrospective analysis of a prospective study of five patients who were successfully treated through a multi-staged approach but in the same hospital admission, not previously described, for the repair of contaminated primary and recurrent giant incisional herniae in a district general hospital between 2009 and 2012. Patient demographics including their BMI and ASA, previous and current operative history including complications and follow-up were collected in a secure database. The first stage involved the eradication of contamination, and the second stage was the definitive hernia repair with the new generation-coated synthetic meshes. Of the five patients, three were men and two women with a mean age of 58 (45-74) years. Two patients had grade 4 while the remaining had grade 3 hernia as per the hernia grading system with a mean BMI of 35 (30-46). All patients required extensive adhesiolysis, bowel resection and anastomoses and wash out. Hernial defect was measured as 204* (105-440) cm(2), size of mesh implant was 568* (375-930) cm(2) and the total duration of operation (1st + 2nd Stage) was 354* (270-540) min. Duration of hospital stay was 11* (7-19) days with a follow-up of 17* (6-36) months. We believe that our multi-staged approach in the same hospital admission (for the repair of contaminated primary and recurrent giant incisional herniae), excludes the disadvantages of a true multi-staged approach and simultaneously minimises the risks and complications associated with a single-staged repair, can be adopted for these challenging patients for a successful outcome (* indicates mean).

Metal Ion-Loaded Nanofibre Matrices for Calcification Inhibition in Polyurethane Implants

PubMed Central

Singh, Charanpreet; Wang, Xungai

2017-01-01

Pathologic calcification leads to structural deterioration of implant materials via stiffening, stress cracking, and other structural disintegration mechanisms, and the effect can be critical for implants intended for long-term or permanent implantation. This study demonstrates the potential of using specific metal ions (MI)s for inhibiting pathological calcification in polyurethane (PU) implants. The hypothesis of using MIs as anti-calcification agents was based on the natural calcium-antagonist role of Mg2+ ions in human body, and the anti-calcification effect of Fe3+ ions in bio-prosthetic heart valves has previously been confirmed. In vitro calcification results indicated that a protective covering mesh of MI-doped PU can prevent calcification by preventing hydroxyapatite crystal growth. However, microstructure and mechanical characterisation revealed oxidative degradation effects from Fe3+ ions on the mechanical properties of the PU matrix. Therefore, from both a mechanical and anti-calcification effects point of view, Mg2+ ions are more promising candidates than Fe3+ ions. The in vitro MI release experiments demonstrated that PU microphase separation and the structural design of PU-MI matrices were important determinants of release kinetics. Increased phase separation in doped PU assisted in consistent long-term release of dissolved MIs from both hard and soft segments of the PU. The use of a composite-sandwich mesh design prevented an initial burst release which improved the late (>20 days) release rate of MIs from the matrix. PMID:28644382

Long-term outcomes of synthetic transobturator nonabsorbable anterior mesh versus anterior colporrhaphy in symptomatic, advanced pelvic organ prolapse surgery.

PubMed

Lo, Tsia-Shu; Pue, Leng Boi; Tan, Yiap Loong; Wu, Pei-Ying

2014-02-01

Anterior vaginal mesh (AVM) combined with sacrospinous ligament fixation (SSF) yields better long-term success rates over anterior colporrhaphy (AC) in advanced pelvic organ prolapse (POP) surgery, with a low rate of mesh-related complications. Medical records of 198 patients who underwent surgery for POP between January 2006 and March 2010 were reviewed retrospectively. Patients' assessment at baseline and third-year postoperative follow-up were analyzed. SSF plus AC or AVM was performed for apical and anterior compartment repair. Primary outcome was objective cure [Pelvic Organ Prolapse Quantification (POP-Q) stage ≤ 1)], and subjective cure defined as negative response to questions 2 and 3 on the POPDI-6. Secondary outcomes were complications, symptoms severity and quality of life as measured with validated questionnaires. Post-operative data were available for 186 patients, 72 in AC group and 114 in AVM group were analyzed. The mean age, parity and operating time in AVM group were significantly higher as compared to AC group. The overall objective and subjective cure rate in AVM group was significantly higher than AC group (90.3 % and 88.6 % versus 73.6 % and 70.8 %, with P value = 0.003 and 0.002 respectively). Mesh exposure rate was 3.5 %. Improvement in both POPDI-6 and PISQ-12 in AVM group was statistically significant compared to AC group. Transobturator synthetic nonabsorbable AVM combined with SSF yielded a favorable and sustainable result over 5 years as compared to traditional AC, both in anatomical and subjective success rate. Mesh related morbidities were low and acceptable.

A prospective 1-year clinical and radiographic study of implants placed after maxillary sinus floor augmentation with synthetic biphasic calcium phosphate or deproteinized bovine bone.

PubMed

Lindgren, Christer; Mordenfeld, Arne; Hallman, Mats

2012-03-01

The technique of using bone grafts or different biomaterials for augmentation of the maxillary sinus prior to implant placement is well accepted by clinicians. However, clinical documentation of some bone substitutes is still lacking. This prospective study was designed to evaluate the success rate of implants placed after maxillary sinus augmentation with a novel synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB), the latter acting as control. Nine edentulous patients and two partially edentulous patients with a mean age of 67 years with a bilateral need for sinus augmentation, < 5 mm residual bone in the floor of the sinus and a crestal width ≥ 4 mm, were included in the study. After bilateral elevation of the Schneiderian membrane, all patients were randomized for augmentation with synthetic BCP in one side and DBB in the contralateral side. After 8 months of graft healing, 62 implants with an SLActive surface were placed. Implant survival, graft resorption, plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth, and implant success rate were evaluated after 1 year of functional loading. After a mean of 118 days, all patients received their fixed prosthetic constructions. One implant was lost in each biomaterial, giving an overall survival rate of 96.8%. Success rates for implants placed in BCP and DBB were 91.7 and 95.7%, respectively. No significant difference in marginal bone loss was found around implants placed in BCP, DBB, or residual bone, respectively. The mean graft resorption was 0.43 mm (BCP) and 0.29 mm (DBB). In this limited study, implant success rate was not dependent on the biomaterial used for maxillary sinus augmentation. Similar results were found after 1 year of functional loading for implants placed after sinus augmentation using BCP or DBB. © 2010 Wiley Periodicals, Inc.

Bone augmentation at peri-implant dehiscence defects comparing a synthetic polyethylene glycol hydrogel matrix vs. standard guided bone regeneration techniques.

PubMed

Thoma, Daniel S; Jung, Ui-Won; Park, Jin-Young; Bienz, Stefan P; Hüsler, Jürg; Jung, Ronald E

2017-07-01

The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri-implant bone regeneration as traditional guided bone regeneration procedures. In 12 beagle dogs, implant placement and peri-implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box-shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA/TCP mixed with a synthetic PEG hydrogel, ii)HA/TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA/TCP covered with a native collagen membrane (CM), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro-CT and histological analyses were performed. Histomorphometric analysis revealed a greater relative augmented area for groups with bone augmentation (43.3%-53.9% at 8 weeks, 31.2%-42.8% at 16 weeks) compared to empty controls (22.9% at 8 weeks, 1.1% at 16 weeks). The median amount of newly formed bone was greatest in group CM at both time-points. Regarding the first bone-to-implant contact, CM was statistically significantly superior to all other groups at 8 weeks. Bone can partially be regenerated at peri-implant buccal dehiscence defects using traditional guided bone regeneration techniques. The use of a PEG hydrogel applied as a matrix mixed with a synthetic bone substitute material might lack a sufficient stability over time for this kind of defect. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Immediate effects of the initial FDA notification on the use of surgical mesh for pelvic organ prolapse surgery in medicare beneficiaries.

PubMed

Reynolds, W Stuart; Gold, Karen P; Ni, Shenghua; Kaufman, Melissa R; Dmochowski, Roger R; Penson, David F

2013-04-01

Prompted by increased reports of complications with the use of mesh for pelvic organ prolapse (POP) surgery, the FDA issued an initial public health notification (PHN) in 2008. We proposed to determine if the numbers of POP cases augmented with surgical mesh performed in U.S. Medicare beneficiaries changed relative to this PHN. Using administrative healthcare claims for beneficiaries enrolled in the U.S. Medicare program from 2008 to 2009, we identified women who underwent POP surgery with and without surgical mesh by procedural and diagnosis coding. In addition to comparing cases with and without mesh, we also calculated rates (number of cases per 100,000 female beneficiaries) and compared these relative to the timing of the PHN. We identified 104,185 POP procedures, of which 27,839 (26.7%) included mesh material and 76,346 (73.3%) did not. Between the last three quarters of 2008 and the first three of 2009, the rates of mesh cases increased (40.3-42.1, P < 0.001) and those without mesh decreased (115.5-111.4, P < 0.001). Inpatient procedures decreased and outpatient procedures increased for both those with and without mesh augmentation. For inpatient procedures, the relative use of biologic graft and synthetic mesh material did not vary over the study period. A substantial number of Medicare beneficiaries underwent mesh POP procedures in 2008-2009. However, despite the PHN cautioning about potential mesh complications, the numbers of mesh cases continued to rise in the immediate period after the PHN. Copyright © 2012 Wiley Periodicals, Inc.

The Role of the Surgeon on Outcomes of Vaginal Prolapse Surgery With Mesh.

PubMed

Eilber, Karyn S; Alperin, Marianna; Khan, Aqsa; Wu, Ning; Pashos, Chris L; Clemens, J Quentin; Anger, Jennifer T

Adverse outcomes after surgery for pelvic organ prolapse (POP) with mesh are often attributed to the mesh material with little attention paid to the influence of surgeon factors. We used a national data set to determine whether surgeon case volume and specialty influenced vaginal prolapse surgery outcomes with mesh. Public Use File data on a 5% random national sample of female Medicare beneficiaries were obtained from the Centers for Medicare and Medicaid Services. Women with a diagnosis of POP who underwent surgery with mesh between 2007 and 2008 were identified by relevant International Classification of Diseases, 9th Revision, Clinical Modification and Current Procedural Terminology, 4th Edition procedure codes. Outcomes were compared by surgeon case volume and specialty. From 2007 to 2008, 1657 surgeries for POP were performed with mesh. Low-, intermediate-, and high-volume surgeons performed 881 (53%), 408 (25%), and 368 (22%) of the cases with mesh, respectively. The cumulative reoperation rates for low-, intermediate-, and high-volume providers were 6%, 2%, and 3%, respectively. The difference in reoperation rates between low and intermediate and low- and high-volume surgeons was statistically significant (P = 0.007 and 0.003, respectively). There was no significant difference in reoperation rates between gynecologists and urologists when vaginal mesh was implanted for POP surgery. Low-volume surgeons performed most of the vaginal prolapse repairs with mesh and had significantly higher reoperation rates. Surgeon experience must be a consideration when reporting mesh-related complications of POP surgery.

A Novel Use of Three-dimensional High-frequency Ultrasonography for Early Pregnancy Characterization in the Mouse.

PubMed

Peavey, Mary C; Reynolds, Corey L; Szwarc, Maria M; Gibbons, William E; Valdes, Cecilia T; DeMayo, Francesco J; Lydon, John P

2017-10-24

High-frequency ultrasonography (HFUS) is a common method to non-invasively monitor the real-time development of the human fetus in utero. The mouse is routinely used as an in vivo model to study embryo implantation and pregnancy progression. Unfortunately, such murine studies require pregnancy interruption to enable follow-up phenotypic analysis. To address this issue, we used three-dimensional (3-D) reconstruction of HFUS imaging data for early detection and characterization of murine embryo implantation sites and their individual developmental progression in utero. Combining HFUS imaging with 3-D reconstruction and modeling, we were able to accurately quantify embryo implantation site number as well as monitor developmental progression in pregnant C57BL6J/129S mice from 5.5 days post coitus (d.p.c.) through to 9.5 d.p.c. with the use of a transducer. Measurements included: number, location, and volume of implantation sites as well as inter-implantation site spacing; embryo viability was assessed by cardiac activity monitoring. In the immediate post-implantation period (5.5 to 8.5 d.p.c.), 3-D reconstruction of the gravid uterus in both mesh and solid overlay format enabled visual representation of the developing pregnancies within each uterine horn. As genetically engineered mice continue to be used to characterize female reproductive phenotypes derived from uterine dysfunction, this method offers a new approach to detect, quantify, and characterize early implantation events in vivo. This novel use of 3-D HFUS imaging demonstrates the ability to successfully detect, visualize, and characterize embryo-implantation sites during early murine pregnancy in a non-invasive manner. The technology offers a significant improvement over current methods, which rely on the interruption of pregnancies for gross tissue and histopathologic characterization. Here we use a video and text format to describe how to successfully perform ultrasounds of early murine pregnancy to generate reliable and reproducible data with reconstruction of the uterine form in mesh and solid 3-D images.

Coarse mesh and one-cell block inversion based diffusion synthetic acceleration

NASA Astrophysics Data System (ADS)

Kim, Kang-Seog

DSA (Diffusion Synthetic Acceleration) has been developed to accelerate the SN transport iteration. We have developed solution techniques for the diffusion equations of FLBLD (Fully Lumped Bilinear Discontinuous), SCB (Simple Comer Balance) and UCB (Upstream Corner Balance) modified 4-step DSA in x-y geometry. Our first multi-level method includes a block Gauss-Seidel iteration for the discontinuous diffusion equation, uses the continuous diffusion equation derived from the asymptotic analysis, and avoids void cell calculation. We implemented this multi-level procedure and performed model problem calculations. The results showed that the FLBLD, SCB and UCB modified 4-step DSA schemes with this multi-level technique are unconditionally stable and rapidly convergent. We suggested a simplified multi-level technique for FLBLD, SCB and UCB modified 4-step DSA. This new procedure does not include iterations on the diffusion calculation or the residual calculation. Fourier analysis results showed that this new procedure was as rapidly convergent as conventional modified 4-step DSA. We developed new DSA procedures coupled with 1-CI (Cell Block Inversion) transport which can be easily parallelized. We showed that 1-CI based DSA schemes preceded by SI (Source Iteration) are efficient and rapidly convergent for LD (Linear Discontinuous) and LLD (Lumped Linear Discontinuous) in slab geometry and for BLD (Bilinear Discontinuous) and FLBLD in x-y geometry. For 1-CI based DSA without SI in slab geometry, the results showed that this procedure is very efficient and effective for all cases. We also showed that 1-CI based DSA in x-y geometry was not effective for thin mesh spacings, but is effective and rapidly convergent for intermediate and thick mesh spacings. We demonstrated that the diffusion equation discretized on a coarse mesh could be employed to accelerate the transport equation. Our results showed that coarse mesh DSA is unconditionally stable and is as rapidly convergent as fine mesh DSA in slab geometry. For x-y geometry our coarse mesh DSA is very effective for thin and intermediate mesh spacings independent of the scattering ratio, but is not effective for purely scattering problems and high aspect ratio zoning. However, if the scattering ratio is less than about 0.95, this procedure is very effective for all mesh spacing.

Mesh materials and hernia repair

PubMed Central

Elango, Santhini; Perumalsamy, Sakthivel; Ramachandran, Krishnakumar; Vadodaria, Ketankumar

2017-01-01

Hernia incidence has been observed since ancient time. Advancement in the medical textile industry came up with the variety of mesh materials to repair hernia, but none of them are without complications including recurrence of hernia. Therefore individuals once developed with the hernia could not lead a healthy and comfortable life. This drawn attention of surgeons, patients, researchers and industry to know the exact mechanism behind its development, complications and recurrence. Recent investigations highlighted the role of genetic factors and connective tissue disorders being the reason for the development of hernia apart from the abnormal pressure that is known to develop during other disease conditions. This review discusses different mesh materials, their advantages and disadvantages and their biological response after its implantation. PMID:28840830

Total knee arthroplasty with a computer-navigated saw: a pilot study.

PubMed

Garvin, Kevin L; Barrera, Andres; Mahoney, Craig R; Hartman, Curtis W; Haider, Hani

2013-01-01

Computer-aided surgery aims to improve implant alignment in TKA but has only been adopted by a minority for routine use. A novel approach, navigated freehand bone cutting (NFC), is intended to achieve wider acceptance by eliminating the need for cumbersome, implant-specific mechanical jigs and avoiding the expense of navigation. We determined cutting time, surface quality, implant fit, and implant alignment after NFC of synthetic femoral specimens and the feasibility and alignment of a complete TKA performed with NFC technology in cadaveric specimens. Seven surgeons prepared six synthetic femoral specimens each, using our custom NFC system. Cutting times, quality of bone cuts, and implant fit and alignment were assessed quantitatively by CT surface scanning and computational measurements. Additionally, a single surgeon performed a complete TKA on two cadaveric specimens using the NFC system, with cutting time and implant alignment analyzed through plain radiographs and CT. For the synthetic specimens, femoral coronal alignment was within ± 2° of neutral in 94% of the specimens. Sagittal alignment was within 0° to 5° of flexion in all specimens. Rotation was within ± 1° of the epicondylar axis in 97% of the specimens. The mean time to make cuts improved from 13 minutes for the first specimen to 9 minutes for the fourth specimen. TKA was performed in two cadaveric specimens without complications and implants were well aligned. TKA is feasible with NFC, which eliminates the need for implant-specific instruments. We observed a fast learning curve. NFC has the potential to improve TKA alignment, reduce operative time, and reduce the number of instruments in surgery. Fewer instruments and less sterilization could reduce costs associated with TKA.

[Morphology of collagen matrices for tissue engineering (biocompatibility, biodegradation, tissue response)].

PubMed

Shekhter, A B; Guller, A E; Istranov, L P; Istranova, E V; Butnaru, D V; Vinarov, A Z; Zakharkina, O L; Kurkov, A V; Kantimerov, D F; Antonov, E N; Marisov, L V; Glybochko, P V

2015-01-01

to perform a comparative morphological study of biocompatibility, biodegradation, and tissue response to implantation of collagen matrices (scaffolds) for tissue engineering in urology and other areas of medicine. Nine matrix types, such as porous materials reconstructed from collagen solution; a collagen sponge-vicryl mesh composite; decellularized and freeze-dried bovine, equine, and fish dermis; small intestinal submucosa, decellularized bovine dura mater; and decellularized human femoral artery, were implanted subcutaneously in 225 rats. The tissues at the implantation site were investigated for a period of 5 to 90 days. Classical histology and nonlinear optical microscopy (NLOM) were applied. The investigations showed no rejection of all the collagen materials. The period of matrix bioresorption varied from 10 days for collagen sponges to 2 months for decellularized and freeze-dried vessels and vicryl meshes. Collagen was prone to macrophage resorption and enzymatic lysis, being replaced by granulation tissue and then fibrous tissue, followed by its involution. NLOM allowed the investigators to study the number, density, interposition, and spatial organization of collagen structures in the matrices and adjacent tissues, and their change over time during implantation. The performed investigation could recommend three matrices: hybrid collagen/vicryl composite; decellularized bovine dermis; and decellularized porcine small intestinal submucosa, which are most adequate for tissue engineering in urology. These and other collagen matrices may be used in different areas of regenerative medicine.

Evaluation of Electrospun Nanofiber-Anchored Silicone for the Degenerative Intervertebral Disc

PubMed Central

Riahanizad, S.

2017-01-01

The nucleus pulposus (NP) substitution by polymeric gel is one of the promising techniques for the repair of the degenerative intervertebral disc (IVD). Silicone gel is one of the potential candidates for a NP replacement material. Electrospun fiber anchorage to silicone disc, referred as ENAS disc, may not only improve the biomechanical performances of the gel but it can also improve restoration capability of the gel, which is unknown. This study successfully produced a novel process to anchor any size and shape of NP gel with electrospun fiber mesh. Viscoelastic properties of silicone and ENAS disc were measured using standard experimental techniques and compared with the native tissue properties. Ex vivo mechanical tests were conducted on ENAS disc-implanted rabbit tails to the compare the mechanical stability between intact and ENAS implanted spines. This study found that viscoelastic properties of ENAS disc are higher than silicone disc and comparable to the viscoelastic properties of human NP. The ex vivo studies found that the ENAS disc restore the mechanical functionality of rabbit tail spine, after discectomy of native NP and replacing the NP by ENAS disc. Therefore, the PCL ENF mesh anchoring technique to a NP implant can have clinical potential. PMID:29181144

Evaluation of a new composite prosthesis for the repair of abdominal wall defects.

PubMed

Losi, Paola; Munaò, Antonella; Spiller, Dario; Briganti, Enrica; Martinelli, Ilaria; Scoccianti, Marco; Soldani, Giorgio

2007-10-01

The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. The present investigation evaluates the behaviour in terms of adhesion formation and integration of a new composite prosthesis that could be employed in this clinical application. Full-thickness abdominal wall defects (7 x 5 cm) were created in 16 anaesthetized New Zealand white rabbits and the prosthesis were placed in direct contact with the visceral peritoneum during the experiment. The defects were repaired with a composite prosthesis or pure polypropylene mesh to establish two study groups (n = 8 each). The composite device was constituted by a polypropylene mesh physically attached to a poly(ether)urethane-polydimethylsiloxane laminar sheet. Animals were sacrificed 7, 14, 21 and 30 days after implant and prosthesis/surrounding tissue specimens subjected to light and electron microscopy. Firm adhesions were detected in the polypropylene implants, while they were not present in the composite implants. The excellent behaviour of the composite prosthesis shown in this study warrants further investigation on its use for the repair of abdominal wall defects when a prosthetic device needs to be placed in contact with the intestinal loops.

Prolonged amelioration of experimental postoperative pain by bupivacaine released from microsphere-coated hernia mesh.

PubMed

Ohri, Rachit; Wang, Jeffery Chi-Fei; Pham, Lan; Blaskovich, Phillip D; Costa, Daniel; Nichols, Gary; Hildebrand, William; Scarborough, Nelson; Herman, Clifford; Strichartz, Gary R

2014-01-01

Postoperative pain alters physiological functions and delays discharge. Perioperative local anesthetics are effective analgesics in the immediate 1- to 2-day postoperative period, but acute pain often lasts longer. The goal of this work was to develop a local anesthetic formulation adhering to an intraoperative implanted device that reduces pain for at least 3 days after surgery. Six groups, each with 8 rats, were studied. In a control group (group I), one 1.2-cm-long incision of the skin was followed by blunt dissection to separate the skin away from the underlying tissues and closing with 2 sutures. In 3 of the treatment groups, the same surgical procedure was used, with the subcutaneous space formed by the blunt dissection lined with a 1-cm square patch of hernia mesh coated with poly lactide co-glycolic acid microspheres containing approximately 17 mg of bupivacaine (group II), no drug (placebo; group III), or bupivacaine free-base powder (group IV). Uncoated mesh implants (group V) served as a secondary control. A standard bupivacaine solution (0.4 mL, 0.5%; 2-mg dose) was infiltrated subcutaneously 30 minutes before the surgery and served as a standard control (group VI). Mechanosensitivity of the skin was tested by the local subcutaneous muscle responses to cutaneous tactile stimulation by von Frey hairs with forces of 4 g (for allodynia) and 15 g (for hyperalgesia) preoperatively and for 7 postoperative days. Control rats (group I) showed mechanohypersensitivity, indicative of postoperative allodynia and hyperalgesia, for all 7 postoperative days. Mechanohyperalgesia in rats that received mesh coated with bupivacaine-releasing microspheres (group II) was reduced during this period to 13% of control postoperative values (P < 0.001); mesh coated with bupivacaine base (group IV) reduced it by 50% (P = 0.034). The placebo mesh (group III) and uncoated mesh (group V) caused no significant reduction of mechanohypersensitivity, and bupivacaine solution infiltrated before the incision (group VI) reduced hypersensitivity for only approximately 2 hours, an overall insignificant effect. Bupivacaine slowly released for 72 hours from microspheres adsorbed to the hernia mesh significantly suppresses evoked postoperative hypersensitivity for at least 1 week and is more effective than a suspension of these microspheres or preoperative single-shot infiltration of bupivacaine.

MRI Evaluation of an Elastic TPU Mesh under Pneumoperitoneum in IPOM Position in a Porcine Model.

PubMed

Lambertz, A; van den Hil, L C L; Ciritsis, A; Eickhoff, R; Kraemer, N A; Bouvy, N D; Müllen, A; Klinge, U; Neumann, U P; Klink, C D

2018-06-01

The frequency of laparoscopic approaches increased in hernia surgery over the past years. After mesh placement in IPOM position, the real extent of the meshes configurational changes after termination of pneumoperitoneum is still largely unknown. To prevent a later mesh folding it might be useful to place the mesh while it is kept under tension. Conventionally used meshes may lose their Effective Porosity under these conditions due to poor elastic properties. The aim of this study was to evaluate a newly developed elastic thermoplastic polyurethane (TPU) containing mesh that retains its Effective Porosity under mechanical strain in IPOM position in a porcine model. It was visualized under pneumoperitoneum using MRI in comparison to polyvinylidenefluoride (PVDF) meshes with similar structure. In each of ten minipigs, a mesh (TPU containing or native PVDF, 10 × 20 cm) was randomly placed in IPOM position at the center of the abdominal wall. After 8 weeks, six pigs underwent MRI evaluation with and without pneumoperitoneum to assess the visibility and elasticity of the mesh. Finally, pigs were euthanized and abdominal walls were explanted for histological and immunohistochemical assessment. The degree of adhesion formation was documented. Laparoscopic implantation of elastic TPU meshes in IPOM position was feasible and safe in a minipig model. Mesh position could be precisely visualized and assessed with and without pneumoperitoneum using MRI after 8 weeks. Elastic TPU meshes showed a significantly higher surface increase under pneumoperitoneum in comparison to PVDF. Immunohistochemically, the amount of CD45-positive cells was significantly lower and the Collagen I/III ratio was significantly higher in TPU meshes after 8 weeks. There were no differences regarding adhesion formation between study groups. The TPU mesh preserves its elastic properties in IPOM position in a porcine model after 8 weeks. Immunohistochemistry indicates superior biocompatibility regarding CD45-positive cells and Collagen I/III ratio in comparison to PVDF meshes with a similar structure.

In vivo evaluation of biofunctionalized implant surfaces with a synthetic peptide (P-15) and its impact on osseointegration. A preclinical animal study.

PubMed

Schmitt, Christian M; Koepple, Markus; Moest, Tobias; Neumann, Konrad; Weisel, Tamara; Schlegel, Karl Andreas

2016-11-01

The overall aim of the study was to investigate a biofunctionalized implant surface with electrochemically deposition of hydroxyapatite and the synthetic peptide (P-15) and its effect on osseointegration. Three modified implant types of ANKYLOS ® C/X implants were used; (1) machined implants used as negative control (M, n = 20), (2) implants with the FRIADENT ® plus surface (grit blasted and acid-etched) used as positive control (P, n = 20), and (3) implants with a biomimetic surface consisting of hydroxyapatite and the synthetic 15 aminoacids containing peptide P-15 (BP, n = 40). The implants were randomly inserted in the mandibles of 10 beagle dogs following 4 months after tooth extraction (P1-P4). Three animals were sacrificed 2 and 7 days after implant insertion, respectively, and four animals were sacrificed 6 months post implant insertion. Bone-to-implant contacts (BICs) were analyzed via histomorphometrical analyses at five different region of interests (ROIs); two at the middle part on either side of the implant (ROI 1/4), two at the apical part of the implant at each side (ROI 2/3), and one at the tip of the implant (ROI 5). All implant surfaces showed a high level of osseointegration and osteoconductivity. The cumulative implant survival rate (CSR) was 93.8%, 100% in the M, 85% in the P, and 95% in the BP group. No statistical difference in BICs at ROI 1/4, 2/3, and 5 could be shown between implant types following 2 and 7 days of healing. BIC values increased in all groups over time. After 6 months of healing the BP group showed superiority in BIC in ROI 2/3 (73.2 ± 15.6%) compared to the P (48.3 ± 10.6%) and M group (66.3 ± 30.2%) with a significant difference between BP and P (P = 0.002). It is hypothesized, that the surface biofunctionalization improves peri-implant bone formation and remodeling, leading to an increased bone-to implant contact. However, within the limitations of the study set-up no benefit in the early phase of osseointegration could be established for dental implants with P-15 containing surface in this study. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Medical Textiles as Vascular Implants and Their Success to Mimic Natural Arteries

PubMed Central

Singh, Charanpreet; Wong, Cynthia S.; Wang, Xungai

2015-01-01

Vascular implants belong to a specialised class of medical textiles. The basic purpose of a vascular implant (graft and stent) is to act as an artificial conduit or substitute for a diseased artery. However, the long-term healing function depends on its ability to mimic the mechanical and biological behaviour of the artery. This requires a thorough understanding of the structure and function of an artery, which can then be translated into a synthetic structure based on the capabilities of the manufacturing method utilised. Common textile manufacturing techniques, such as weaving, knitting, braiding, and electrospinning, are frequently used to design vascular implants for research and commercial purposes for the past decades. However, the ability to match attributes of a vascular substitute to those of a native artery still remains a challenge. The synthetic implants have been found to cause disturbance in biological, biomechanical, and hemodynamic parameters at the implant site, which has been widely attributed to their structural design. In this work, we reviewed the design aspect of textile vascular implants and compared them to the structure of a natural artery as a basis for assessing the level of success as an implant. The outcome of this work is expected to encourage future design strategies for developing improved long lasting vascular implants. PMID:26133386

Growth promoting in vitro effect of synthetic cyclic RGD-peptides on human osteoblast-like cells attached to cancellous bone.

PubMed

Magdolen, Ursula; Auernheimer, Jörg; Dahmen, Claudia; Schauwecker, Johannes; Gollwitzer, Hans; Tübel, Jutta; Gradinger, Reiner; Kessler, Horst; Schmitt, Manfred; Diehl, Peter

2006-06-01

In tissue engineering, the application of biofunctional compounds on biomaterials such as integrin binding RGD-peptides has gained growing interest. Anchorage-dependent cells like osteoblasts bind to these peptides thus ameliorating the integration of a synthetic implant. In case sterilized bone grafts are used as substitutes for reconstruction of bone defects, the ingrowth of the implanted bone is often disturbed because of severe pretreatment such as irradiation or autoclaving, impairing the biological and mechanical properties of the bone. We report for the first time on the in vitro coating of the surface of freshly resected, cleaned bone discs with synthetic, cyclic RGD-peptides. For this approach, two different RGD-peptides were used, one containing two phosphonate anchors, the other peptide four of these binding moieties to allow efficient association of these reactive RGD-peptides to the inorganic bone matrix. Human osteoblast-like cells were cultured on RGD-coated bone discs and the adherence and growth of the cells were analyzed. Coating of bone discs with RGD-peptides did not improve the adhesion rate of osteoblast-like cells to the discs but significantly (up to 40%) accelerated growth of these cells within 8 days after attachment. This effect points to pretreatment of bone implants, especially at the critical interface area between the implanted bone and the non-resected residual bone structure, before re-implantation in order to stimulate and enhance osteointegration of a bone implant.

3D unstructured-mesh radiation transport codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morel, J.

1997-12-31

Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options:more » $$S{_}n$$ (discrete-ordinates), $$P{_}n$$ (spherical harmonics), and $$SP{_}n$$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $$S{_}n$$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.« less

Does topical rifampicin reduce the risk of surgical field infection in hernia repair?

PubMed Central

Kahramanca, Şahin; Kaya, Oskay; Azılı, Cem; Celep, Bahadır; Gökce, Emre; Küçükpınar, Tevfik

2013-01-01

Objective: Inguinal hernia operations are common procedures in general surgery. There have been many approaches in the historical development of hernia repair; tension free repair with mesh being the most commonly used technique today. Although it is a clean wound, antibiotic use is still controversial due to concerns about infection related to synthetic mesh. We aimed to determine the probable role of topical rifampicin in patients with tension-free hernia repair and mesh support. Material and Methods: The charts of patients who underwent tension-free inguinal hernia repair were retrospectively analyzed. Information and operative notes on patients, in whom synthetic materials were used, were identified. The patients were divided into two groups, placebo group (G1) and patients with application of topical rifampicin on the mesh (G2). Infection rates between the groups in the early postoperative period were compared. Results: The mean age of the 278 patients who were included in the study was 49.6±15.39 and the female/male ratio was 10/268. There were recurrent hernias in four patients and superficial wound infections in 22 patients in the early period. One patient had testicle torsion and underwent an orchiectomy. There were no significant differences between the groups in terms of age and gender. The types of hernia and body mass index were homogenous between the two groups. In the early postoperative period the infection rates were 16/144 (11.1%) and 6/134 (4.48%) in the groups, respectively, with the difference being statistically significant (p=0.041). Conclusion: We suggest that applying rifampicin locally can decrease surgical site infection in hernia operations where meshes are used. PMID:25931846

Image-guided sphenoid wing meningioma resection and simultaneous computer-assisted cranio-orbital reconstruction: technical case report.

PubMed

Westendorff, Carsten; Kaminsky, Jan; Ernemann, Ulrike; Reinert, Siegmar; Hoffmann, Jürgen

2007-02-01

Resection of large intraosseous sphenoid wing meningiomas is traditionally associated with significant morbidity. Rapid prototyping techniques have become widely used for treatment planning. Yet, the transfer of a treatment plan into the intraoperative situs strongly depends on the experience of the individual surgeon. Extensive resection with orbital decompression was planned and performed on the basis of rapid prototyping and surgical navigation techniques in a 44-year-old woman presenting with a large sphenoid wing meningioma on the right infiltrating the orbit. Tumor resection was simulated on a stereolithography model of the patient's head. The stereolithography model was scanned using computed tomography (CT) and the defect geometry was used to create a custom-made titanium implant. The implant consisted of a solid titanium core and a spot-welded titanium mesh surrounding the core, allowing for minor intraoperative adjustments of the implant size by reducing the mesh size. The stereolithography model with the incorporated implant was CT scanned again and the CT data were fused with the patient's original CT data. The implant borders indicating the resection borders were marked within the patient's CT data set. This treatment plan was transferred to an optical navigation system. Intraoperatively, tumor resection was performed using surgical navigation. In the presented case report, the combination of computer-assisted planning using rapid prototyping techniques and image-guided surgery allowed for an extensive tumor resection precisely according to a preoperative treatment plan in a patient presenting with a large intraosseous sphenoid wing meningioma. A larger clinical series with a long-term follow-up period will be needed to determine the reproducibility.

Effects of mesenchymal stem cell and fibroblast coating on immunogenic potential of prosthetic meshes in vitro.

PubMed

Gao, Yue; Krpata, David M; Criss, Cory N; Liu, Lijia; Posielski, Natasza; Rosen, Michael J; Novitsky, Yuri W

2014-08-01

The aim of this study was to reveal the effect of fibroblast or mesenchymal stem cell (MSC) coating on the mesh-induced production of IL-1β, IL-6, and VEGF by macrophages. Four commonly used surgical meshes were tested in this study, including Parietex, SoftMesh, TIGR, and Strattice. One-square-centimeter pieces of each mesh were placed on top of a monolayer of human fibroblasts or rat MSCs. The coating status was monitored with a light microscope. The human promonocytic cell line U937 was induced to differentiate into macrophages (MΦ). Three weeks later, meshes were transferred to new 24-well plates and cocultured with the MΦs for 72 h. Culture medium was collected and analyzed for IL-1β, IL-6, and VEGF production using standard ELISA essays. Parallel mesh samples were fixed with paraformaldehyde or glutaraldehyde for histology or transmission electronic microscopy (TEM) analyses, respectively. Uncoated meshes induced increased production of all three cytokines compared with macrophages cultured alone. HF coating further increased the production of both IL-6 and VEGF but reduced IL-1β production. Except for the SoftMesh group, MSC coating significantly blunted release of all cytokines to levels even lower than with MΦs cultured alone. MΦs tended to deteriorate in the presence of MSCs. Both histology and TEM revealed intimate interactions between cell-coated meshes and MΦs. Cytokine response to fibroblast coating varied, while MSC coating blunted the immunogenic effect of both synthetic and biologic meshes in vitro. Cell coating appears to affect mesh biocompatibility and may become a key process in mesh evolution.

A rare postoperative complication of anterior lower thoracic instrumentation: diaphragmatic laceration with hemothorax.

PubMed

Wong, Yat Wa; Cheung, Jason Pui Yin; Luk, Keith Dip Kei; Cheung, Kenneth Man Chee

2017-05-01

To highlight the importance of preventing visceral injury due to prominent anterior implants at the spinal column. A 52-year-old man with cord compression was treated with a T9/10 discectomy and instrumented fusion via a right thoracotomy and trans-pleural approach. Postoperatively, he had improved lower limb numbness. However, after a bout of coughing, there was sudden increase in chest drain output, hemodynamic instability and massive fluid collection in the right chest cavity. Emergency re-exploration of the thoracotomy was performed and a 6 cm laceration of the right postero-medial diaphragm was identified as the bleeding source and was found to be in close proximity with the locking nut of the anterior implants. The laceration was repaired and a soft synthetic patch was used to cover the implants. Postoperatively, the hemothorax resolved and the patient recovered from the neurological deficit. Prevention of diaphragmatic injury can be performed using lower profile and less sharp-edged implants. Implant coverage with a soft synthetic material is necessary if unable to perform direct repair of the parietal pleura over the implants.

[The primary stability between manual and robot assisted implantation of hip prostheses: A biomechanical study on synthetic femurs].

PubMed

Decking, J; Gerber, A; Kränzlein, J; Meurer, A; Böhm, B; Plitz, W

2004-01-01

We investigated the initial stability of cementless stems implanted with robotic milling and conventional manual broaching. Proximally porous structured stems (G2, ESKA-Implants, Luebeck, Germany) were implanted into synthetic femora. In one group, the femoral cavity was prepared by a CT-based robot (CASPAR, URS-Ortho, Germany) with a high-speed milling head. In the other group, femora were rasped manually with broaches. The broaches had 1 mm proximal press-fit, the robotic cavities 1.5 mm. The implants were exposed to 15 000 loading cycles with 1 000 +/- 500 N. The direction of forces on the implant head were chosen to simulate stair climbing. Internal rotation and translation (caudal, dorsal and lateral) of the implants were measured by linear transducers. The robotic group showed significantly less reversible motion regarding translation in caudal, dorsal and lateral directions. The standard deviations of implant motions were smaller in the robotic group. Using robotic preparation of the femur, initial stability was higher and more consistent than with manual broaching, but differences in undersizing of the cavities created in the femur in relation to the implant may have contributed to these differences for the most part. In-vitro-loading experiments focusing on femoral cavities with varying press-fits are recommended before the introduction of new implants or operating procedures.

Correlation-based regularization and gradient operators for (joint) inversion on unstructured meshes

NASA Astrophysics Data System (ADS)

Jordi, Claudio; Doetsch, Joseph; Günther, Thomas; Schmelzbach, Cedric; Robertsson, Johan

2017-04-01

When working with unstructured meshes for geophysical inversions, special attention should be paid to the design of the operators that are used for regularizing the inverse problem and coupling of different property models in joint inversions. Regularization constraints for inversions on unstructured meshes are often defined in a rather ad-hoc manner and usually only involve the cell to which the operator is applied and its direct neighbours. Similarly, most structural coupling operators for joint inversion, such as the popular cross-gradients operator, are only defined in the direct neighbourhood of a cell. As a result, the regularization and coupling length scales and strength of these operators depend on the discretization as well as cell sizes and shape. Especially for unstructured meshes, where the cell sizes vary throughout the model domain, the dependency of the operator on the discretization may lead to artefacts. Designing operators that are based on a spatial correlation model allows to define correlation length scales over which an operator acts (called footprint), reducing the dependency on the discretization and the effects of variable cell sizes. Moreover, correlation-based operators can accommodate for expected anisotropy by using different length scales in horizontal and vertical directions. Correlation-based regularization operators also known as stochastic regularization operators have already been successfully applied to inversions on regular grids. Here, we formulate stochastic operators for unstructured meshes and apply them in 2D surface and 3D cross-well electrical resistivity tomography data inversion examples of layered media. Especially for the synthetic cross-well example, improved inversion results are achieved when stochastic regularization is used instead of a classical smoothness constraint. For the case of cross-gradients operators for joint inversion, the correlation model is used to define the footprint of the operator and weigh the contributions of the property values that are used to calculate the cross-gradients. In a first series of synthetic-data tests, we examined the mesh dependency of the cross-gradients operators. Compared to operators that are only defined in the direct neighbourhood of a cell, the dependency on the cell size of the cross-gradients calculation is markedly reduced when using operators with larger footprints. A second test with synthetic models focussed on the effect of small-scale variabilities of the parameter value on the cross-gradients calculation. Small-scale variabilities that are superimposed on a global trend of the property value can potentially degrade the cross-gradients calculation and destabilize joint inversion. We observe that the cross-gradients from operators with footprints larger than the length scale of the variabilities are less affected compared to operators with a small footprint. In joint inversions on unstructured meshes, we thus expect the correlation-based coupling operators to ensure robust coupling on a physically meaningful scale.

Transvaginal single-incision mesh reconstruction for recurrent or advanced anterior vaginal wall prolapse.

PubMed

Marschke, J; Hengst, L; Schwertner-Tiepelmann, N; Beilecke, K; Tunn, R

2015-05-01

Single-incision transvaginal mesh for reconstruction of Level I and II prolapses in women with recurrent or advanced prolapse. We evaluated functional, anatomical, sonomorphological and quality-of-life outcome. Data were collected retrospectively for preoperative parameters and at follow-up visits. Anatomical cure was assessed with vaginal examination using the ICS-POP-Q system; introital-ultrasound scan for postvoidal residual and description of mesh characteristics was performed. We applied a visual analogue scale (VAS) and the German Pelvic Floor Questionnaire to assess quality-of-life. Seventy women with cystocele (III: 61.3%/IV: 16%), all post-hysterectomy and in majority (81.4%) after previous cystocele repair, were operated using a single-incision transvaginal technique. Overall anatomical success rate was 95.7% with significant improvement in quality-of-life (p < 0.0001). Mesh erosion occurred in 5.7%, one patient presented symptomatic vaginal vault prolapse. Postvoidal residual declined significantly (58 vs. 2.9%). Sonographic mesh length was 55.7% of implanted mesh with a wide range of mesh position, but no signs of mesh dislocation. There was no de novo dyspareunia reported, one case of preoperative existing dyspareunia worsened. No severe adverse event was observed. We hereby present a trial of a high-risk group of patients requiring reconstruction of anterior and apical vaginal wall in mostly recurrent prolapse situation. Our data support the hypothesis of improved anatomical and functional results and less mesh shrinkage caused by the single-incision technique with fixation in sacrospinous ligament in combination with modification in mesh quality compared to former multi-incision techniques.

Urinary Incontinence

MedlinePlus

... stress incontinence. The sling is either a narrow piece of synthetic (man-made) mesh or a piece of tissue from your own body that your ... the United States. World Journal of Urology; 20(6): 327–336. American College of Obstetricians and Gynecologists. ( ...

In vivo results of hydrogel composite pericardial substitutes.

PubMed

Blue, M A; Guilbeau, E J; Brandon, T A; Walker, A S; Bjotvedt, G; Fisk, R L

1991-01-01

In this study, two improved pericardial patches were developed and evaluated for their efficacy as pericardial substitutes. The patches are composites consisting of a hydrogel (PHEMA) that coats an underlying mesh (either ETFE or PET). Studies were conducted using subcutaneous implants in rats and pericardial patch implants in greyhound dogs. Adhesions between the substitute and pericardium and the epicardium were minimal. The ETFE composite patch caused an unacceptable epicardial reaction. The PET patch results were encouraging; the epicardium was largely unaffected by the patch.

Treatment of first metatarsophalangeal joint arthritis using hemiarthroplasty with a synthetic cartilage implant or arthrodesis: A comparison of operative and recovery time.

PubMed

Glazebrook, Mark; Younger, Alastair S E; Daniels, Timothy R; Singh, Dishan; Blundell, Chris; de Vries, Gwyneth; Le, Ian L D; Nielsen, Dominic; Pedersen, M Elizabeth; Sakellariou, Anthony; Solan, Matthew; Wansbrough, Guy; Baumhauer, Judith F

2017-05-29

First metatarsophalangeal joint (MTPJ1) hemiarthroplasty using a novel synthetic cartilage implant was as effective and safe as MTPJ1 arthrodesis in a randomized clinical trial. We retrospectively evaluated operative time and recovery period for implant hemiarthroplasty (n=152) and MTPJ1 arthrodesis (n=50). Perioperative data were assessed for operative and anaesthesia times. Recovery and return to function were prospectively assessed with the Foot and Ankle Ability Measure (FAAM) Sports and Activities of Daily Living (ADL) subscales and SF-36 Physical Functioning (PF) subscore. Mean operative time for hemiarthroplasty was 35±12.3min and 58±21.5min for arthrodesis (p<0.001). Anaesthesia duration was 28min shorter with hemiarthroplasty (p<0.001). At weeks 2 and 6 postoperative, hemiarthroplasty patients demonstrated clinically and statistically significantly higher FAAM Sport, FAAM ADL, and SF-36 PF subscores versus arthrodesis patients. MTPJ1 hemiarthroplasty with a synthetic cartilage implant took less operative time and resulted in faster recovery than arthrodesis. III, Retrospective case control study. Copyright © 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Organ culture in 3-dimensional matrix: in vitro model for evaluating biological compliance of synthetic meshes for abdominal wall repair.

PubMed

Dasdia, T; Bazzaco, S; Bottero, L; Buffa, R; Ferrero, S; Campanelli, G; Dolfini, E

1998-01-01

A new in vitro method to evaluate the early critical interactions between synthetic prosthetic materials and growing tissues is reported. The correct spatial organization and proper cell to cell interaction required to mimic the in vivo environment was obtained in a 3-dimensional (3-D) embryo organ culture. The clot formed by plasma and chick-embryo extract provided a natural 3-D extracellular matrix that was able to support the growth and differentiation of intestinal tissue dissected from 12-day-old chick embryos. Different materials used for the repair of abdominal wall defects were taken as standards; all the prosthetic materials were devoid of any evident cytotoxic potential over a 10-day culture period, so they did not interfere with the organogenesis process. A polyglactin mesh (Vicryl) was fully incorporated into the growing tissue, but early signs of its degradation were detectable. The biologically inert materials polyethylene terephthalate (Mersilene) and polypropylene (Marlex, Prolene, and Herniamesh) retained their structural integrity when incubated with cultured tissue at 37 degrees C, and they did not hinder cellular proliferation or fibroblast migration. However, the outgrowth behavior was very different while the connective tissue invaded the interstices of the polyethylene terephthalate mesh; the explants and the migrating cells were repelled by hydrophobic polypropylene meshes. These findings are in agreement with other reported results in in vivo studies. Therefore, this method can be considered as reliable and predictable for the evaluation of biopolymers.

Breast reconstruction with absorbable mesh sling: dynamic infrared thermography of skin envelope

PubMed Central

Hashimoto, Yoko; Yuasa, Takeshi; Suzuki, Yoshinori; Saisho, Hiroshi

2017-01-01

Background To immediate reconstruct ptosis breasts, we used polyglactin (Vicryl; Ethicon Inc., Somerville, NJ, USA) mesh as an inferolateral sling. However, Vicryl mesh is absorbable and losing function as a supporting structure. We doubt about the stability of the blood supply to the inferior part of the flap when it is in direct contact with inner implant. In this study, we examine the complications and the safety of the skin flap of this absorbable mesh sling (AMS) procedure. Methods The outcomes of 80 cases were examined, and the 1-year safety record of 40 cases was assessed. Complications were divided into minor complications, major complications requiring surgical intervention, and major complications requiring the reconstructive surgery to be halted. In addition, we examined the blood perfusion of the skin flap by dynamic infrared thermography (DIRT). Results Among 80 patients with AMS procedure, 73 breasts were reconstructed immediately and in one-stage. Complication outcomes are presented; there were 4 cases of minor flap necrosis (5%) and 4 of major complications resulting in surgical correction (5%). One patient required additional surgery, and the implant was moved into the musculocutaneous flap (1.3%). In 40 patients 1 year after surgery, DIRT showed significant decreased of blood perfusion in the ipsilateral inferior sites in comparison with the superior sites. Conclusions Blood perfusion was comparably insufficient in the inferior area of the reconstructed breast mound with AMS, where the pectoralis muscle could not be used to line the inside of the envelope. However, there were no severe flap complications due to ischemia. PMID:28210555

A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model.

PubMed

Trbakovic, Amela; Hedenqvist, Patricia; Mellgren, Torbjörn; Ley, Cecilia; Hilborn, Jöns; Ossipov, Dmitri; Ekman, Stina; Johansson, Carina B; Jensen-Waern, Marianne; Thor, Andreas

2018-03-01

The aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid-calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model. Eighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant. Qualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel. CPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel. The CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of polypropylene mesh and porcine-derived, cross-linked urinary bladder matrix materials implanted in the rabbit vagina and abdomen.

PubMed

Fan, Xuemei; Wang, Yanzhou; Wang, Yu; Xu, Huicheng

2014-05-01

Our aim was to compare histological and biomechanical effects of polypropylene (PP) mesh and porcine-derived, cross-linked urinary bladder matrix (cUBM) graft materials using a rabbit vaginal and abdominal model. Forty rabbits were implanted with PP mesh (n = 20) or cUBM (n = 20) in the vagina and abdomen. Two grafts (PP or cUBM) of the same type were placed into each site, so each rabbit had four grafts. Grafts were harvested 12 weeks later and processed for histologic analysis and biomechanical testing. There were high rates of two types of grafts missing in the vagina. Vaginal PP was associated with erosion reaction (67%), whereas abdominal PP and cUBM showed no sign of erosion. All patches adhered to rectus abdominis or vaginal mucosa and shrank to varying degrees, especially for PP grafts. Compared with vaginal PP, vaginal cUBM induced milder chronic inflammation response, had lower scores (P = 0.000) for inflammation response, and showed higher scores for neovascularization (P = 0.000) and fibroblastic proliferation (P = 0.002). In the abdomen, both histopathological parameters were insignificantly different (P > 0.05) between cUBM and PP. The mechanical properties of UBM did not deteriorate following implantation, whereas the ultimate tensile strength and elastic modulus of vaginal PP increased. PP had higher scores for tensile and break strength than did cUBM (P < 0.05). The cUBM has good biocompatibility, high ability to integrate with the vagina, and maintains mechanical properties in vivo. It may be a promising material for pelvic floor reconstruction.

The effects of cortical bone thickness and trabecular bone strength on noninvasive measures of the implant primary stability using synthetic bone models.

PubMed

Hsu, Jui-Ting; Fuh, Lih-Jyh; Tu, Ming-Gene; Li, Yu-Fen; Chen, Kuan-Ting; Huang, Heng-Li

2013-04-01

This study investigated how the primary stability of a dental implant as measured by the insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ) is affected by varying thicknesses of cortical bone and strengths of trabecular bone using synthetic bone models. Four synthetic cortical shells (with thicknesses of 0, 1, 2, and 3 mm) were attached to four cellular rigid polyurethane foams (with elastic moduli of 137, 47.5, 23, and 12.4 MPa) and one open-cell rigid polyurethane foam which mimic the osteoporotic bone (with an elastic modulus 6.5 MPa), to represent the jawbones with various cortical bone thicknesses and strengths of trabecular bone. A total of 60 bone specimens accompanied with implants was examined by a torque meter, Osstell resonance frequency analyzer, and Periotest electronic device. All data were statistically analyzed by two-way analysis of variance. In addition, second-order nonlinear regression was utilized to assess the correlations of the primary implant stability with the four cortex thicknesses and five strengths of trabecular bone. ITV, ISQ, and PTV differed significantly (p < .05) and were strongly correlated with the thickness of cortical bone (R(2) > 0.9) and the elastic modulus of trabecular bone (R(2) = 0.74-0.99). The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the strength of trabecular bone; however, these factors are mostly nonlinearly correlated with ITV, PTV, and ISQ. Using ITV and PTV seems more suitable for identifying the primary implant stability in osteoporotic bone with a thin cortex. © 2011 Wiley Periodicals, Inc.

Angiogenesis after sintered bone implantation in rat parietal bone.

PubMed

Ohtsubo, S; Matsuda, M; Takekawa, M

2003-01-01

We studied the effect of bone substitutes on revascularization and the restart of blood supply after sintered bone implantation in comparison with synthetic hydroxyapatite implantation and fresh autogenous bone transplantation (control) in rat parietal bones. Methods for the study included the microvascular corrosion cast method and immunohistochemical techniques were also used. The revascularization of the control group was the same as that for usual wound healing in the observations of the microvascular corrosion casts. The sintered bone implantation group was quite similar to that of the control group. In the synthetic hydroxyapatite group, immature newly-formed blood vessels existed even on the 21st day after implantation and the physiological process of angiogenesis was interrupted. Immunohistochemically, vascular endothelial growth factor (VEGF), which activates angiogenesis, appeared at the early stages of both the control group and the sintered bone implantation group. VEGF reduced parallel with the appearance of the transforming growth factor factor-beta-1 (TGF-beta-1), which obstructs angiogenesis, and the angiogenesis passed gradually into the mature stage. In the hydroxyapatite implantation group, TGF-beta-1 appeared at the early stage of the implants. The appearance of VEGF lagged and it existed around the pores of hydroxyapatite even on the 21st day of the implantation. Proliferation and wandering of endothelial cells continued without any maturing of the vessels. These findings suggest that the structure and the components of the implant material affect angiogenesis after implantation as well as new bone formation.

Proposed technique for open repair of a small umbilical hernia and rectus divarication with self-gripping mesh.

PubMed

Privett, B J; Ghusn, M

2016-08-01

There are a group of patients in which umbilical or epigastric hernias co-exist with rectus divarication. These patients have weak abdominal musculature and are likely to pose a higher risk of recurrence following umbilical hernia repair. We would like to describe a technique for open repair of small (<4 cm) midline hernias in patients with co-existing rectus divarication using self-adhesive synthetic mesh. The use of a self-adhesive mesh avoids the need for suture fixation of the mesh in the superior portion of the abdomen, allowing for a smaller skin incision. In 173 patients, preperitoneal self-fixating mesh has been used for the repair of midline hernias <4 cm in diameter. In 58 of these patients, the mesh was extended superiorly to reinforce a concurrent divarication. The described technique offers a simple option for open repair of small midline hernias in patients with co-existing rectus divarication, to decrease the risk of upper midline recurrence in an at-risk patient group. This initial case series is able to demonstrate a suitably low rate of recurrence and complications.

Rate and onset cues can improve cochlear implant synthetic vowel recognition in noise

PubMed Central

Mc Laughlin, Myles; Reilly, Richard B.; Zeng, Fan-Gang

2013-01-01

Understanding speech-in-noise is difficult for most cochlear implant (CI) users. Speech-in-noise segregation cues are well understood for acoustic hearing but not for electric hearing. This study investigated the effects of stimulation rate and onset delay on synthetic vowel-in-noise recognition in CI subjects. In experiment I, synthetic vowels were presented at 50, 145, or 795 pulse/s and noise at the same three rates, yielding nine combinations. Recognition improved significantly if the noise had a lower rate than the vowel, suggesting that listeners can use temporal gaps in the noise to detect a synthetic vowel. This hypothesis is supported by accurate prediction of synthetic vowel recognition using a temporal integration window model. Using lower rates a similar trend was observed in normal hearing subjects. Experiment II found that for CI subjects, a vowel onset delay improved performance if the noise had a lower or higher rate than the synthetic vowel. These results show that differing rates or onset times can improve synthetic vowel-in-noise recognition, indicating a need to develop speech processing strategies that encode or emphasize these cues. PMID:23464025

Integrating Microtissues in Nanofiber Scaffolds for Regenerative Nanomedicine

PubMed Central

Keller, Laetitia; Wagner, Quentin; Offner, Damien; Eap, Sandy; Musset, Anne-Marie; Arruebo, Manuel; Kelm, Jens M.; Schwinté, Pascale; Benkirane-Jessel, Nadia

2015-01-01

A new generation of biomaterials focus on smart materials incorporating cells. Here, we describe a novel generation of synthetic nanofibrous implant functionalized with living microtissues for regenerative nanomedicine. The strategy designed here enhances the effectiveness of therapeutic implants compared to current approaches used in the clinic today based on single cells added to the implant. PMID:28793604

Successful Implantation of a Left Ventricular Assist Device After Treatment With the Paracor HeartNet.

PubMed

Schweiger, Martin; Stepanenko, Alexander; Potapov, Evgenji; Drews, Thorsten; Hetzer, Roland; Krabatsch, Thomas

2010-01-01

The Paracor HeartNet, a ventricular constraint device for the treatment of heart failure (HF), is implanted through a left lateral thoracotomy. It envelopes the heart like a mesh "bag." This method of application raises the question of whether adhesions with the pericardium allow the safe implantation of a left ventricular assist device (LVAD) if HF worsens. A male patient who had undergone implantation of the Paracor HeartNet 42 months earlier presented with advanced HF for cardiac transplantation. The patient's condition deteriorated, and because no suitable organ for transplantation was available, implantation of an LVAD became necessary. Surgery was performed via a median sternotomy without complications. No severe adhesions were found. This is the first report on "how to do" LVAD implantation after Paracor HeartNet implantation with images and information about cutting the constraint. Because the Paracor HeartNet is "wrapped" around the heart, concerns persist that severe adhesions with the pericardium might occur. In this case, LVAD implantation after therapy with the Paracor HeartNet was without complications, and the expected massive adhesions were absent.

Chest wall reconstruction in a canine model using polydioxanone mesh, demineralized bone matrix and bone marrow stromal cells.

PubMed

Tang, Hua; Xu, Zhifei; Qin, Xiong; Wu, Bin; Wu, Lihui; Zhao, XueWei; Li, Yulin

2009-07-01

Extensive chest wall defect reconstruction remains a challenging problem for surgeons. In the past several years, little progress has been made in this area. In this study, a biodegradable polydioxanone (PDO) mesh and demineralized bone matrix (DBM) seeded with osteogenically induced bone marrow stromal cells (BMSCs) were used to reconstruct a 6 cm x 5.5 cm chest wall defect. Four experimental groups were evaluated (n=6 per group): polydioxanone (PDO) mesh/DBMs/BMSCs group, polydioxanone (PDO) mesh/DBMs group, polydioxanone (PDO) mesh group, and a blank group (no materials) in a canine model. All the animals survived except those in the blank group. In all groups receiving biomaterial implants, the polydioxanone (PDO) mesh completely degraded at 24 weeks and was replaced by fibrous tissue with thickness close to that of the normal intercostal tissue (P>0.05). In the polydioxanone (PDO) mesh/DBMs/BMSCs group, new bone formation and bone-union were observed by radiographic and histological examination. More importantly, the reconstructed rib could maintain its original radian and achieve satisfactory biomechanics close to normal ribs in terms of bending stress (P>0.05). However, in the other two groups, fibrous tissue was observed in the defect and junctions, and the reconstructed ribs were easily distorted under an outer force. Based on these results, a surgical approach utilizing biodegradable polydioxanone (PDO) mesh in combination with DBMs and BMSCs could repair the chest wall defect not only in function but also in structure.

A Reduced-Order Model for Efficient Simulation of Synthetic Jet Actuators

NASA Technical Reports Server (NTRS)

Yamaleev, Nail K.; Carpenter, Mark H.

2003-01-01

A new reduced-order model of multidimensional synthetic jet actuators that combines the accuracy and conservation properties of full numerical simulation methods with the efficiency of simplified zero-order models is proposed. The multidimensional actuator is simulated by solving the time-dependent compressible quasi-1-D Euler equations, while the diaphragm is modeled as a moving boundary. The governing equations are approximated with a fourth-order finite difference scheme on a moving mesh such that one of the mesh boundaries coincides with the diaphragm. The reduced-order model of the actuator has several advantages. In contrast to the 3-D models, this approach provides conservation of mass, momentum, and energy. Furthermore, the new method is computationally much more efficient than the multidimensional Navier-Stokes simulation of the actuator cavity flow, while providing practically the same accuracy in the exterior flowfield. The most distinctive feature of the present model is its ability to predict the resonance characteristics of synthetic jet actuators; this is not practical when using the 3-D models because of the computational cost involved. Numerical results demonstrating the accuracy of the new reduced-order model and its limitations are presented.

Preparation and biocompatibility evaluation of polypropylene mesh coated with electrospinning membrane for pelvic defects repair.

PubMed

Lu, Yao; Fu, Shaoju; Zhou, Shuanglin; Chen, Ge; Zhu, Chaoting; Li, Nannan; Ma, Ying

2018-05-01

Composite mesh with different materials composition could compensate for the drawbacks brought by single component mesh. Coating a membrane layer on the surface of macroporous mesh is a common method for preparing composite medical mesh. Electrospinning and dipping methods were introduced to form the two kinds of membrane-coated PP meshes (electro-mesh and dip-mesh); several properties were measured based on subcutaneous implantation model in rat. The results revealed that continuous tissue ingrowth could be observed for electro-mesh only with evidences of strength increase (electro-mesh: 0 week - 13.1 ± 0.88 N, 2 week - 16.87 ± 1.39 N, 4 week - 22.04 ± 2.05 N) and thickness increase (electro-mesh: 0 week - 0.437 ± 0.023 mm, 2 week - 0.488 ± 0.025 mm, 4 week - 0.576 ± 0.028 mm). However, no tissues were observed for dip-mesh in the first 2 weeks, both on macroscopic level and microscopic level, proved by strength data (dip-mesh: 0 week - 13.36 ± 1.06 N, 2 week - 13.4 ± 1.33 N, 4 week - 18.61 ± 1.89 N) and thickness data (dip-mesh: 0 week - 0.439 ± 0.018 mm, 2 week - 0.439 ± 0.019 mm, 4 week - 0.502 ± 0.032 mm). Electro-mesh had larger surface area decrease (10.74 ± 1.22%) than that of dip-mesh (2.78 ± 0.52%). The adhesion level of electro-mesh (medium adhesion) was also higher than that of dip-mesh (mild adhesion). Even if showing differences in several properties, both meshes were similar under histological observation, with the ability to support fresh tissues ingrowth. Considering operation environment, electro-mesh seems more suitable than dip-mesh with a rapid tissue growing, medium adhesion rate for repairing pelvic floor defects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Polypropylene-based composite mesh versus standard polypropylene mesh in the reconstruction of complicated large abdominal wall hernias: a prospective randomized study.

PubMed

Kassem, M I; El-Haddad, H M

2016-10-01

To compare polypropylene mesh positioned onlay supported by omentum and/or peritoneum versus inlay implantation of polypropylene-based composite mesh in patients with complicated wide-defect ventral hernias. This was a prospective randomized study carried out on 60 patients presenting with complicated large ventral hernia in the period from January 2012 to January 2016 in the department of Gastrointestinal Surgery unit and Surgical Emergency of the Main Alexandria University Hospital, Egypt. Large hernia had an abdominal wall defect that could not be closed. Patients were divided into two groups of 30 patients according to the type of mesh used to deal with the large abdominal wall defect. The study included 38 women (63.3 %) and 22 men (37.7 %); their mean age was 46.5 years (range, 25-70). Complicated incisional hernia was the commonest presentation (56.7 %).The operative and mesh fixation times were longer in the polypropylene group. Seven wound infections and two recurrences were encountered in the propylene group. Mean follow-up was 28.7 months (2-48 months). Composite mesh provided, in one session, satisfactory results in patients with complicated large ventral hernia. The procedure is safe and effective in lowering operative time with a trend of low wound complication and recurrence rates.

Usage of a self-adhesive mesh in TAPP hernia repair: A prospective study based on Herniamed Register

PubMed Central

Klobusicky, Pavol; Feyerherd, Peter

2016-01-01

INTRODUCTION: Inguinal hernia repair is one of the most frequently performed surgical procedures worldwide in general surgery. The transabdominal laparoscopic (TAPP) approach in the therapy of inguinal hernia seems to be a suitable alternative to classical open inguinal hernia repair mainly in the hands of an experienced surgeon. TAPP repair offers the possibility of gentle dissection with implantation of the mesh and the possibility of non-invasive fixation of the implanted mesh. MATERIALS AND METHODS: Data analysis encompassed all patients who underwent inguinal hernia surgery at our Surgical Department within the period from July 1, 2012 to September 30, 2014 and who fulfilled the inclusion criteria. The standard surgical technique was used. Data were entered and subsequently analysed on the Herniamed platform. Herniamed is an Internet-based register in German and English, and includes all data of outpatient and hospitalised patients who underwent surgery for some type of hernia. All relevant patient data are collected via Internet. RESULTS: There were 241 patients enrolled in the group and there were 396 inguinal hernias repaired in total. Standard long-term follow-up after 12 months was evaluated in 205 patients (85.06%), and in the rest of the patients during the closing of the study, but at least 6 months after operation. The mean follow-up was at 19.69 months. At the 1-year assessment, mild discomfort was reported in the groin in 10 patients (4.88%) [1-3 on the visual analogue scale (VAS)]. Post-operative pain lasting over 12 months in the groin of moderate degree (4-6 VAS) was reported in two cases (0.97%). There was no recurrence and no chronic post-operative pain of severe degree reported. CONCLUSION: Our study demonstrates that laparoscopic inguinal hernia repair using the TAPP technique with the implantation of a self-fixation mesh is fast, effective, reliable and economically advantageous method in experienced hands and, according to our results, reduces the occurrence of post-herniorrhaphy inguinal pain (CPIP) and has a low recurrence rate. PMID:27279393

Doxycycline alters collagen composition following ventral hernia repair.

PubMed

Tharappel, Job C; Harris, Jennifer W; Totten, Crystal; Zwischenberger, Brittany A; Roth, John S

2017-04-01

Doxycycline, a nonspecific metalloproteinase (MMP) inhibitor, has been demonstrated to impact the strength of the polypropylene (PP) mesh-repaired hernia with an increase in the deposition of collagen type 1. The impact of doxycycline with porcine acellular dermal matrices (PADM) is unknown; therefore, we evaluated the impact of doxycycline administration upon hernia repair with PP and PADM mesh. Sprague-Dawley rats weighing ~400 g underwent laparotomy with creation of a midline ventral hernia. After a 27-day recovery, animals were randomly assigned to four groups of eight and underwent intraperitoneal underlay hernia repair with either PP or PADM. Groups were assigned to daily normal saline (S) or daily doxycycline in normal saline 10 mg/kg (D) via oral gavage for 8 weeks beginning 24 h preoperatively. Animals were euthanized at 8 weeks and underwent tensiometric testing of the abdominal wall and western blot analyses for collagen subtypes and MMPs. Thirty-two animals underwent successful hernia creation and repair with either PADM or PP. At 8 weeks, 15 of 16 PP-implanted animals survived with only 12 of 16 PADM-implanted animals surviving. There were no differences in the mesh to fascial interface tensiometric strength between groups. Densitometric counts in the PADM-D group demonstrated increased collagen type 1 compared to PP-S (PADM-D [1286.5], PADM-S [906.9], PP-S [700.4], p = 0.037) and decreased collagen type 3 compared to PP-S (PADM-D [7446.9], PADM-S [8507.6], PP-S [11,297.1], p = 0.01). MMP-9 levels were increased in PADM-D (PP-S vs. PADM-D, p = 0.04), while MMP-2 levels were similar between PADM-D and PADM-S, respectively. Collagen type 1 deposition at the mesh to fascial interface is enhanced following administration of doxycycline in ventral hernia repairs with porcine acellular dermal matrices. Doxycycline administration may have implications for enhancing hernia repair outcomes using biologic mesh.

Titanium Mesh Shaping and Fixation for the Treatment of Comminuted Mandibular Fractures.

PubMed

Dai, Jiewen; Shen, Guofang; Yuan, Hao; Zhang, Wenbin; Shen, Shunyao; Shi, Jun

2016-02-01

Treating comminuted mandibular fractures remains a challenge. In this study, we used titanium mesh to treat comminuted mandibular fractures. Nine patients with traumatically comminuted mandibular fractures who received open reduction and internal stable fixation with titanium mesh were retrospectively reviewed. Open reduction-internal stable fixation was performed 7 to 10 days after primary debridement of the facial trauma. After the fractured mandible and the displaced fragments were reduced, the titanium mesh was reshaped according to the morphology of the mandible, and the reduced bone fragments were fixed with the reshaped titanium mesh and screws. Then, the surgical effects were evaluated during routine follow-up. Most of the displaced fragments were preserved and exhibited a favorable shaping ability in restoring the morphology of the mandible during surgery. No intraoperative complications were encountered. In addition, all patients were infection free, with no obvious resorption in the fixed fragments after surgery. The mandible also exhibited favorable morphology and offered sufficient bone mass for dental implantation or a denture prosthesis. We conclude that titanium mesh shaping and fixation can effectively treat comminuted mandibular fractures with little bone fragment loss, little soft tissue exposure, a low infection rate, and favorable mandibular morphology. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Finite element strategies to satisfy clinical and engineering requirements in the field of percutaneous valves.

PubMed

Capelli, Claudio; Biglino, Giovanni; Petrini, Lorenza; Migliavacca, Francesco; Cosentino, Daria; Bonhoeffer, Philipp; Taylor, Andrew M; Schievano, Silvia

2012-12-01

Finite element (FE) modelling can be a very resourceful tool in the field of cardiovascular devices. To ensure result reliability, FE models must be validated experimentally against physical data. Their clinical application (e.g., patients' suitability, morphological evaluation) also requires fast simulation process and access to results, while engineering applications need highly accurate results. This study shows how FE models with different mesh discretisations can suit clinical and engineering requirements for studying a novel device designed for percutaneous valve implantation. Following sensitivity analysis and experimental characterisation of the materials, the stent-graft was first studied in a simplified geometry (i.e., compliant cylinder) and validated against in vitro data, and then in a patient-specific implantation site (i.e., distensible right ventricular outflow tract). Different meshing strategies using solid, beam and shell elements were tested. Results showed excellent agreement between computational and experimental data in the simplified implantation site. Beam elements were found to be convenient for clinical applications, providing reliable results in less than one hour in a patient-specific anatomical model. Solid elements remain the FE choice for engineering applications, albeit more computationally expensive (>100 times). This work also showed how information on device mechanical behaviour differs when acquired in a simplified model as opposed to a patient-specific model.

Repair of a Giant Omphalocele in an Infant With a Pericardial Implant Crosslinked With Oligourethane.

PubMed

Vargas-Mancilla, Juan; Torrero-Serrato, María A; Palacios-Rodríguez, Aarón J; Rodríguez-de León, Gloria B; Montes-Rodríguez, Metzeri I; Mendoza-Novelo, Birzabith

2018-04-16

The giant omphalocele (GO) represents a challenge for the pediatric surgeon in its management and wall abdominoplasty. Here, we report the outcome of a case in which a GO in a newborn patient was repaired with an implant derived from decellularized bovine pericardium crosslinked with oligourethane. The implantation time was extended for 6 months. This was then followed up by the retrieval of the implant and the subsequent reconstruction in a second surgical time by the closure of the abdominal wall fascia. A short hospital stay, early integration into the patient's family environment, as well as early onset of the oral route without special care of the implant or reconstructed wall nor food restrictions were observed. The reduced presence of the complications described in the literature after application of surgical meshes suggests that this implant can be an effective and safe alternative method in the treatment of abdominal wall defects such as GO. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Resterilized mesh in repair of abdominal wall defects in rats.

PubMed

Sucullu, Ilker; Akin, Mehmet Levhi; Yitgin, Selahattin; Filiz, Ali Ilker; Kurt, Yavuz

2008-01-01

A variety of negative opinions about repeated usage of relatively expensive resterilized synthetic meshes have been considered. It had been stated that resterilized polypropylene meshes inhibits fibroblastic activity, decreases proliferative activity, and increases apoptosis in human fibroblast culture, in vitro. The purpose of this study is the in vivo evaluation of the resterilized mesh repairs of abdominal hernia defects in rat models of incisional hernia by comparing primer repair and original mesh repairs. The rats (n = 22) were separated into three groups. While the abdominal defect was repaired by primary suture in the control group (CG), the defects were repaired by original mesh (OG) or resterilized mesh (RG) in mesh-repaired groups. After 21 days, the rats were evaluated for tissue tensile strengths, tissue hydroxyproline levels, tissue inflammation, fibrosis, and apoptosis. Although the tensile strengths in OG and RG were significantly higher than those of CG (p < .05 and p < .05), there was no significant difference between two groups. The tissue hydroxyproline levels in OG and RG were also higher than those of CG. The difference was not significant between the two groups. The inflammation and fibrosis indexes in OG and RG were significantly higher than those of CG (p < .0001 for both), but there was no difference between groups. While the apoptosis index in OG and RG was also higher than that of CG (p < .0001 for both), there was no significant difference between OG and RG. The usage of resterilized mesh in abdominal wall repair did not reduce the tissue tensile strength, did not affect the tissue hydroxyproline levels, did not decrease the fibrosis, and did not increase the tissue inflammation and apoptosis. In conclusion, usage of resterilized meshes in abdominal wall defects was as safe as sterilized meshes.

Phospho-silicate and silicate layers modified by hydroxyapatite particles

NASA Astrophysics Data System (ADS)

Rokita, M.; Brożek, A.; Handke, M.

2005-06-01

Common used metal materials do not ensure good connection between an implant and biological neighbourhood. Covering implants by thin silicate or phosphate layers enable to improve biological properties of implants and create conditions for producing the non-concrete bonding between the implant and tissue. The project includes preparing silicate sols of different concentrations and proper (powder) fraction of synthetic as well as natural ox hydroxyapatite, depositing the sol mixed with hydroxyapatite onto the base material (metal, ceramic carbon) and heat treatment. Our work includes also preparation of phospho-silicate layers deposited onto different base materials using sol-gel method. Deposited sols were prepared regarding composition, concentration and layer heat treatment conditions. The prepared layers are examined to determine their phase composition (XRD, IR spectroscopy methods), density and continuity (scanning microscopy with EDX methods). Biological activity of layers was evaluated by means of estimation of their corrosive resistance in synthetic body fluids ('in vitro' method) and of bone cells growth on the layers surface. Introducing hydroxyapatite to the layer sol should improve connection between tissue and implant as well as limit the disadvantageous, corrosive influence of implant material (metal) on the tissue.

Numerical assessment of bone remodeling around conventionally and early loaded titanium and titanium-zirconium alloy dental implants.

PubMed

Akça, Kıvanç; Eser, Atılım; Çavuşoğlu, Yeliz; Sağırkaya, Elçin; Çehreli, Murat Cavit

2015-05-01

The aim of this study was to investigate conventionally and early loaded titanium and titanium-zirconium alloy implants by three-dimensional finite element stress analysis. Three-dimensional model of a dental implant was created and a thread area was established as a region of interest in trabecular bone to study a localized part of the global model with a refined mesh. The peri-implant tissues around conventionally loaded (model 1) and early loaded (model 2) implants were implemented and were used to explore principal stresses, displacement values, and equivalent strains in the peri-implant region of titanium and titanium-zirconium implants under static load of 300 N with or without 30° inclination applied on top of the abutment surface. Under axial loading, principal stresses in both models were comparable for both implants and models. Under oblique loading, principal stresses around titanium-zirconium implants were slightly higher in both models. Comparable stress magnitudes were observed in both models. The displacement values and equivalent strain amplitudes around both implants and models were similar. Peri-implant bone around titanium and titanium-zirconium implants experiences similar stress magnitudes coupled with intraosseous implant displacement values under conventional loading and early loading simulations. Titanium-zirconium implants have biomechanical outcome comparable to conventional titanium implants under conventional loading and early loading.

Repairing a Facial Cleft by Polyether-Ether-Ketone Implant Combined With Titanium Mesh.

PubMed

Deng, Yuan; Tang, Weiwei; Li, Zhengkang

2018-05-15

The Tessier Number 4 cleft is one of the rarest, most complex craniofacial anomalies that presents difficulties in surgical treatment. In this article, we report a case of simultaneous facial depression, eye displacement, and medial canthus deformity. In this case, the maxillary bony defect was reconstructed using computer-assisted design computer-assisted manufacturing (CAD-CAM) polyether-ether-ketone (PEEK) material, and the orbital floor defect was repaired with AO prefabricated titanium mesh. Additionally, the medial canthus was modified with canthopexy and a single Z-plasty flap. Owing to its relative rarity and varied clinical presentations, no definitive operative methods have been accepted for Tessier No. 4 facial cleft. This study presents the combination of CAD-CAM manufactured PEEK material and titanium mesh as an alternative approach for reconstructing the bony defect of Tessier No. 4 facial clefts.

Does the Vaginal Flora Modify When a Synthetic Mesh is Used for Genital Prolapse Repair in Postmenopausal Women? A Pilot, Randomized Controlled Study.

PubMed

de Castro, Edilson Benedito; Brito, Luiz Gustavo Oliveria; Giraldo, Paulo César; Teatin Juliato, Cássia Raquel

2018-01-10

The vaginal flora from postmenopausal women with pelvic organ prolapse (POP) is different from younger women. We hypothesized that the decision of a surgical route using a mesh would modify the vaginal flora. The purpose of this study was to analyze the vaginal flora from postmenopausal women that were submitted to abdominal sacrocervicopexy or vaginal sacrospinous fixation. A pilot, randomized controlled study with 50 women aged 55 to 75 years (n = 25; abdominal sacrocervicopexy + subtotal hysterectomy; n = 25 vaginal sacrospinous fixation + vaginal hysterectomy) was performed. A polyvinylidene mesh was used in both arms. The vaginal content analysis was collected before and 60 days after the surgery. The type of flora, the presence of lactobacilli/leukocytes, and the Nugent criteria were analyzed. Most of the women were white (80%), with at least 1 comorbidity (69.9%), did not present sexual activity (60%), and presented advanced stage 4 POP. Two thirds of women presented a type 3 flora, and half of them did not present lactobacilli (48.3%). About the Nugent criteria, 51.7% presented normal flora, 46.6% found altered flora, and 1.7% had bacterial vaginosis. There were no differences about the type of flora (P = 1), number of lactobacilli (P = 0.9187), Nugent criteria (P = 0.4235), inflammation (P = 0.1018), and bacterial vaginosis (P = 0.64) before and after surgery in both groups. In this pilot study, the use of synthetic mesh by vaginal or abdominal route did not affect the vaginal flora in postmenopausal women operated on by POP surgery.

Quantification of in vitro wear of a synthetic meniscus implant using gravimetric and micro-CT measurements.

PubMed

Elsner, Jonathan J; Shemesh, Maoz; Shefy-Peleg, Adaya; Gabet, Yankel; Zylberberg, Eyal; Linder-Ganz, Eran

2015-09-01

A synthetic meniscus implant was recently developed for the treatment of patients with mild to moderate osteoarthritis with knee pain associated with medial joint overload. The implant is distinctively different from most orthopedic implants in its pliable construction, and non-anchored design, which enables implantation through a mini-arthrotomy without disruption to the bone, cartilage, and ligaments. Due to these features, it is important to show that the material and design can withstand knee joint conditions. This study evaluated the long-term performance of this device by simulating loading for a total of 5 million gait cycles (Mc), corresponding to approximately five years of service in-vivo. All five implants remained in good condition and did not dislodge from the joint space during the simulation. Mild abrasion was detected by electron microscopy, but µ-CT scans of the implants confirmed that the damage was confined to the superficial surfaces. The average gravimetric wear rate was 14.5 mg/Mc, whereas volumetric changes in reconstructed µ-CT scans point to an average wear rate of 15.76 mm(3)/Mc (18.8 mg/Mc). Particles isolated from the lubricant had average diameter of 15 µm. The wear performance of this polycarbonate-urethane meniscus implant concept under ISO-14243 loading conditions is encouraging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

A novel adaptive algorithm for 3D finite element analysis to model extracortical bone growth.

PubMed

Cheong, Vee San; Blunn, Gordon W; Coathup, Melanie J; Fromme, Paul

2018-02-01

Extracortical bone growth with osseointegration of bone onto the shaft of massive bone tumour implants is an important clinical outcome for long-term implant survival. A new computational algorithm combining geometrical shape changes and bone adaptation in 3D Finite Element simulations has been developed, using a soft tissue envelope mesh, a novel concept of osteoconnectivity, and bone remodelling theory. The effects of varying the initial tissue density, spatial influence function and time step were investigated. The methodology demonstrated good correspondence to radiological results for a segmental prosthesis.

Comparison of a lightweight polypropylene mesh (Optilene® LP) and a large-pore knitted PTFE mesh (GORE® INFINIT® mesh)--Biocompatibility in a standardized endoscopic extraperitoneal hernia model.

PubMed

Jacob, Dietmar A; Schug-Pass, Christine; Sommerer, Florian; Tannapfel, Andrea; Lippert, Hans; Köckerling, Ferdinand

2012-02-01

The use of a mesh with good biocompatibility properties is of decisive importance for the avoidance of recurrences and chronic pain in endoscopic hernia repair surgery. As we know from numerous experiments and clinical experience, large-pore, lightweight polypropylene meshes possess the best biocompatibility. However, large-pore meshes of different polymers may be used as well and might be an alternative solution. Utilizing a totally extraperitoneal technique in an established animal model, 20 domestic pigs were implanted with either a lightweight large-pore polypropylene (PP) mesh (Optilene® LP) or a medium-weight large-pore knitted polytetrafluorethylene (PTFE) mesh (GORE® INFINIT® mesh). After 94 days, the pigs were sacrificed and postmortem diagnostic laparoscopy was performed, followed by explantation of the specimens for macroscopic, histological and immunohistochemical evaluation. The mean mesh shrinkage rate was 14.2% for Optilene® LP vs. 24.7% for INFINIT® mesh (p = 0.017). The partial volume of the inflammatory cells was 11.2% for Optilene® LP vs. 13.9% for INFINIT (n.s.). CD68 was significantly higher for INFINIT (11.8% vs. 5.6%, p = 0.007). The markers of cell turnover, namely Ki67 and the apoptotic index, were comparable at 6.4% vs. 12.4% (n.s.) and 1.6% vs. 2.0% (n.s.). In the extracellular matrix, TGF-β was 35.4% for Optilene® LP and 31.0% for INFINIT® (n.s.). Collagen I (pos/300 μm) deposits were 117.8 and 114.9, respectively. In our experimental examinations, Optilene® LP and INFINIT® showed a comparable biocompatibility in terms of chronic inflammatory reaction; however, the shrinkage rate was significantly higher for INFINIT® after 3 months. The higher shrinkage rate of INFINIT® should be taken into account when choosing the mesh size for an adequate hernia overlap.

New injectable elastomeric biomaterials for hernia repair and their biocompatibility.

PubMed

Skrobot, J; Zair, L; Ostrowski, M; El Fray, M

2016-01-01

Complications associated with implantation of polymeric hernia meshes remain a difficult surgical challenge. We report here on our work, developing for the first time, an injectable viscous material that can be converted to a solid and elastic implant in vivo, thus successfully closing herniated tissue. In this study, long-chain fatty acids were used for the preparation of telechelic macromonomers end-capped with methacrylic functionalities to provide UV curable systems possessing high biocompatibility, good mechanical strength and flexibility. Two different systems, comprising urethane and ester bonds, were synthesized from non-toxic raw materials and then subjected to UV curing after injection of viscous material into the cavity at the abdominal wall during hernioplasty in a rabbit hernia model. No additional fixation or sutures were required. The control group of animals was treated with commercially available polypropylene hernia mesh. The observation period lasted for 28 days. We show here that artificially fabricated defect was healed and no reherniation was observed in the case of the fatty acid derived materials. Importantly, the number of inflammatory cells found in the surrounding tissue was comparable to these found around the standard polypropylene mesh. No inflammatory cells were detected in connective tissues and no sign of necrosis has been observed. Collectively, our results demonstrated that new injectable and photocurable systems can be used for minimally invasive surgical protocols in repair of small hernia defects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Next Generation Orthopaedic Implants by Additive Manufacturing Using Electron Beam Melting

PubMed Central

Murr, Lawrence E.; Gaytan, Sara M.; Martinez, Edwin; Medina, Frank; Wicker, Ryan B.

2012-01-01

This paper presents some examples of knee and hip implant components containing porous structures and fabricated in monolithic forms utilizing electron beam melting (EBM). In addition, utilizing stiffness or relative stiffness versus relative density design plots for open-cellular structures (mesh and foam components) of Ti-6Al-4V and Co-29Cr-6Mo alloy fabricated by EBM, it is demonstrated that stiffness-compatible implants can be fabricated for optimal stress shielding for bone regimes as well as bone cell ingrowth. Implications for the fabrication of patient-specific, monolithic, multifunctional orthopaedic implants using EBM are described along with microstructures and mechanical properties characteristic of both Ti-6Al-4V and Co-29Cr-6Mo alloy prototypes, including both solid and open-cellular prototypes manufactured by additive manufacturing (AM) using EBM. PMID:22956957

Custom-Made Synthetic Scaffolds for Bone Reconstruction: A Retrospective, Multicenter Clinical Study on 15 Patients

PubMed Central

Macchi, Aldo; Luongo, Giuseppe

2016-01-01

Purpose. To present a computer-assisted-design/computer-assisted-manufacturing (CAD/CAM) technique for the design, fabrication, and clinical application of custom-made synthetic scaffolds, for alveolar ridge augmentation. Methods. The CAD/CAM procedure consisted of (1) virtual planning/design of the custom-made scaffold; (2) milling of the scaffold into the exact size/shape from a preformed synthetic bone block; (3) reconstructive surgery. The main clinical/radiographic outcomes were vertical/horizontal bone gain, any biological complication, and implant survival. Results. Fifteen patients were selected who had been treated with a custom-made synthetic scaffold for ridge augmentation. The scaffolds closely matched the shape of the defects: this reduced the operation time and contributed to good healing. A few patients experienced biological complications, such as pain/swelling (2/15: 13.3%) and exposure of the scaffold (3/15: 20.0%); one of these had infection and complete graft loss. In all other patients, 8 months after reconstruction, a well-integrated newly formed bone was clinically available, and the radiographic evaluation revealed a mean vertical and horizontal bone gain of 2.1 ± 0.9 mm and 3.0 ± 1.0 mm, respectively. Fourteen implants were placed and restored with single crowns. The implant survival rate was 100%. Conclusions. Although positive outcomes have been found with custom-made synthetic scaffolds in alveolar ridge augmentation, further studies are needed to validate this technique. PMID:28070512

Prospective, Randomized, Multi-centered Clinical Trial Assessing Safety and Efficacy of a Synthetic Cartilage Implant Versus First Metatarsophalangeal Arthrodesis in Advanced Hallux Rigidus.

PubMed

Baumhauer, Judith F; Singh, Dishan; Glazebrook, Mark; Blundell, Chris; De Vries, Gwyneth; Le, Ian L D; Nielsen, Dominic; Pedersen, M Elizabeth; Sakellariou, Anthony; Solan, Matthew; Wansbrough, Guy; Younger, Alastair S E; Daniels, Timothy

2016-05-01

Although a variety of great toe implants have been tried in an attempt to maintain toe motion, the majority have failed with loosening, malalignment/dislocation, implant fragmentation and bone loss. In these cases, salvage to arthrodesis is more complicated and results in shortening of the ray or requires structural bone graft to reestablish length. This prospective study compared the efficacy and safety of this small (8/10 mm) hydrogel implant to the gold standard of a great toe arthrodesis for advanced-stage hallux rigidus. In this prospective, randomized non-inferiority study, patients from 12 centers in Canada and the United Kingdom were randomized (2:1) to a synthetic cartilage implant or first metatarsophalangeal (MTP) joint arthrodesis. VAS pain scale, validated outcome measures (Foot and Ankle Ability Measure [FAAM] sport scale), great toe active dorsiflexion motion, secondary procedures, radiographic assessment, and safety parameters were evaluated. Analysis was performed using intent-to-treat (ITT) and modified ITT (mITT) methodology. The primary endpoint for the study consisted of a single composite endpoint using the 3 primary study outcomes (pain, function, and safety). The individual subject's outcome was considered a success if all of the following criteria were met: (1) improvement (decrease) from baseline in VAS pain of ≥30% at 12 months; (2) maintenance of function from baseline in FAAM sports subscore at 12 months; and (3) absence of major safety events at 2 years. The proportion of successes in each group was determined and 1-sided 95% confidence interval for the difference between treatment groups was calculated. Noninferiority of the implant to arthrodesis was considered statistically significant if the 1-sided 95% lower confidence interval was greater than the equivalence limit (<15%). A total of 236 patients were initially enrolled; 17 patients withdrew prior to randomization, 17 patients withdrew after randomization, and 22 were nonrandomized training patients, leaving 152 implant and 50 arthrodesis patients. Standard demographics and baseline outcomes were similar for both groups. VAS pain scores decreased significantly in both the implant and arthrodesis groups from baseline at 12 and 24 months. Similarly, the FAAM sports and activity of daily living subscores improved significantly at 12 and 24 months in both groups. First MTP active dorsiflexion motion improvement was 6.2 degrees (27.3%) after implant placement and was maintained at 24 months. Subsequent secondary surgeries occurred in 17 (11.2%) implant patients (17 procedures) and 6 (12.0%) arthrodesis patients (7 procedures). Fourteen (9.2%) implants were removed and converted to arthrodesis, and 6 (12.0%) arthrodesis patients (7 procedures [14%]) had isolated screws or plate and screw removal. There were no cases of implant fragmentation, wear, or bone loss. When analyzing the ITT and mITT population for the primary composite outcome of VAS pain, function (FAAM sports), and safety, there was statistical equivalence between the implant and arthrodesis groups. A prospective, randomized (2:1), controlled, noninferiority clinical trial was performed to compare the safety and efficacy of a small synthetic cartilage bone implant to first MTP arthrodesis in patients with advanced-stage hallux rigidus. This study showed equivalent pain relief and functional outcomes. The synthetic implant was an excellent alternative to arthrodesis in patients who wished to maintain first MTP motion. The percentage of secondary surgical procedures was similar between groups. Less than 10% of the implant group required revision to arthrodesis at 2 years. Level I, prospective randomized study. © The Author(s) 2016.

Statistical Analysis of Compressive and Flexural Test Results on the Sustainable Adobe Reinforced with Steel Wire Mesh

NASA Astrophysics Data System (ADS)

Jokhio, Gul A.; Syed Mohsin, Sharifah M.; Gul, Yasmeen

2018-04-01

It has been established that Adobe provides, in addition to being sustainable and economic, a better indoor air quality without spending extensive amounts of energy as opposed to the modern synthetic materials. The material, however, suffers from weak structural behaviour when subjected to adverse loading conditions. A wide range of mechanical properties has been reported in literature owing to lack of research and standardization. The present paper presents the statistical analysis of the results that were obtained through compressive and flexural tests on Adobe samples. Adobe specimens with and without wire mesh reinforcement were tested and the results were reported. The statistical analysis of these results presents an interesting read. It has been found that the compressive strength of adobe increases by about 43% after adding a single layer of wire mesh reinforcement. This increase is statistically significant. The flexural response of Adobe has also shown improvement with the addition of wire mesh reinforcement, however, the statistical significance of the same cannot be established.

Onlay with Adhesive Use Compared with Sublay Mesh Placement in Ventral Hernia Repair: Was Chevrel Right? An Americas Hernia Society Quality Collaborative Analysis.

PubMed

Haskins, Ivy N; Voeller, Guy R; Stoikes, Nathaniel F; Webb, David L; Chandler, Robert G; Phillips, Sharon; Poulose, Benjamin K; Rosen, Michael J

2017-05-01

The use of mesh during ventral hernia repair (VHR) is a well-accepted concept. However, the ideal location of mesh placement remains strongly debated. Although VHR with onlay mesh placement has historically been associated with a high rate of wound events, this surgical approach is technically less challenging than VHR with sublay mesh placement. The purpose of this study was to compare 30-day wound events after onlay mesh placement with adhesive fixation vs those after sublay mesh placement using the Americas Hernia Society Quality Collaborative database. All patients undergoing elective, open VHR with synthetic mesh placement from January 2013 through January 2016 were identified within the Americas Hernia Society Quality Collaborative. Only patients with clean wounds were included. Patients were divided into 2 groups: onlay mesh placement with the use of adhesive and sublay mesh placement. The association of mesh location with 30-day wound events was investigated using a matched analysis. A total of 1,854 patients met inclusion criteria; 1,761 (95.0%) underwent sublay mesh placement and 93 (5.0%) underwent onlay mesh placement with the use of adhesive. A 2:1 sublay to onlay matched analysis was performed based on factors previously shown to influence wound events after VHR. After matching, both groups had a lower mean Ventral Hernia Working Group grade and fewer associated comorbidities. There was no statistically significant difference between the sublay and onlay groups with respect to 30-day surgical site infections (2.9% vs 5.5%; p = 0.30), surgical site occurrences (15.2% vs 7.7%; p = 0.08), or surgical site occurrences requiring procedural intervention (8.2% vs 5.5%; p = 0.42). Ventral hernia repair with onlay mesh placement is a safe alternative to VHR with sublay mesh placement in low-risk patients. Additional studies are needed to determine the long-term mesh outcomes and recurrence rates in both of these groups. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

High Throughput Assay for Bacterial Adhesion on Acellular Dermal Matrices and Synthetic Surgical Materials

PubMed Central

Nyame, Theodore T.; Lemon, Katherine P.; Kolter, Roberto; Liao, Eric C.

2013-01-01

Background There has been increasing use of various synthetic and biologically derived materials in surgery. Biologic surgical materials are used in many plastic surgery procedures, ranging from breast reconstruction to hernia repairs. In particular, acellular dermal matrix (ADM) material has gained popularity in these applications. There is a paucity of data on how ADM compares to other surgical materials as a substrate for bacterial adhesion, the first step in formation biofilm, which occurs in prosthetic wound infections. We have designed a high throughput assay to evaluate Staphylococcus aureus adherence on various synthetic and biologically derived materials. Methods Clinical isolates of Staphylococcus aureus (strains SC-1 and UAMS-1) were cultured with different materials and bacterial adherence was measured using a resazurin cell vitality reporter microtiter assay. Four materials that are commonly utilized in reconstructive procedures were evaluated: prolene mesh, vicryl mesh, and two different ADM preparations (AlloDerm®, FlexHD®). We were able to develop a high throughput and reliable assay for quantifying bacterial adhesion on synthetic and biologically derived materials. Results The resazurin vitality assay can be reliably used to quantify bacterial adherence to acellular dermal matrix material, as well as synthetic material. S. aureus strains SC-1 and UAMS-1 both adhered better to ADM materials (AlloDerm® vs. FlexHD®) than to the synthetic material prolene. S. aureus also adhered better to vicryl than to prolene. Strain UAMS-1 adhered better to vicryl and ADM materials than did strain SC-1. Conclusion Our results suggest that S. aureus adheres more readily to ADM material than to synthetic material. We have developed an assay to rapidly test bacterial formation on surgical materials, using two S. aureus bacterial strains. This provides a standard method to evaluate existing and new materials with regard to bacterial adherence and potential propensity for infection. This assay is particularly important in the clinical context of the severe sequelae of post-operative infection. PMID:22030489

Association Between Patient Factors and Outcome of Synthetic Cartilage Implant Hemiarthroplasty vs First Metatarsophalangeal Joint Arthrodesis in Advanced Hallux Rigidus.

PubMed

Goldberg, Andy; Singh, Dishan; Glazebrook, Mark; Blundell, Chris M; De Vries, Gwyneth; Le, Ian L D; Nielsen, Dominic; Pedersen, M Elizabeth; Sakellariou, Anthony; Solan, Matthew; Younger, Alastair S E; Daniels, Timothy R; Baumhauer, Judith F

2017-11-01

We evaluated data from a clinical trial of first metatarsophalangeal joint (MTPJ1) implant hemiarthroplasty and arthrodesis to determine the association between patient factors and clinical outcomes. Patients ≥18 years with hallux rigidus grade 2, 3, or 4 were treated with synthetic cartilage implant MTPJ1 hemiarthroplasty or arthrodesis. Pain visual analog scale (VAS), Foot and Ankle Ability Measure (FAAM) sports and activities of daily living (ADL) scores, and Short Form-36 Physical Function (SF-36 PF) subscore were obtained preoperatively, and at 2, 6, 12, 24, 52, and 104 weeks postoperatively. Final outcome data, great toe active dorsiflexion motion, secondary procedures, radiographs, and safety parameters were evaluated for 129 implant hemiarthroplasties and 47 arthrodeses. The composite primary endpoint criteria for clinical success included VAS pain reduction ≥30%, maintenance/improvement in function, no radiographic complications, and no secondary surgical intervention at 24 months. Predictor variables included hallux rigidus grade; gender; age; body mass index (BMI); symptom duration; prior MTPJ1 surgery; preoperative hallux valgus angle, range of motion (ROM), and pain. Two-sided Fisher exact test was used ( P < .05). Patient demographics and baseline outcome measures were similar. Success rates between implant MTPJ1 hemiarthroplasty and arthrodesis were similar ( P > .05) when stratified by hallux rigidus grade, gender, age, BMI, symptom duration, prior MTPJ1 surgery status, and preoperative VAS pain, hallux valgus, and ROM. Synthetic cartilage implant hemiarthroplasty was appropriate for patients with grade 2, 3, or 4 hallux rigidus. Its results in those with associated mild hallux valgus (≤20 degrees) or substantial preoperative stiffness were equivalent to MTPJ1 fusion, irrespective of gender, age, BMI, hallux rigidus grade, preoperative pain or symptom duration. Level II, randomized clinical trial.

Graft and mesh use in vaginal surgery.

PubMed

Rizvi, Raheela Mohsin; Chughtai, Novera Ghayoor

2017-12-01

Pelvic organ prolapse and urinary incontinence are among the most common chronic disorders in women. These are common problems whose pathogenesis remains unclear. As life expectancy increases, significantly greater number of women now present with pelvic organ prolapse and urinary incontinence requiring surgical intervention. Currently, the lifetime risk of undergoing prolapse or continence surgery is one in 11, and up to 30% of patients will require repeat reconstructive surgery and repeat surgery for incontinence in 10%. In an attempt to improve surgical outcomes and to preserve vaginal capacity and coital function, a number of synthetic and biological prostheses have been developed. This review aims to look at the role of graft and mesh in vaginal surgery. We conducted a search for English-language articles published during 1997 to 2016, using MEDLINE, PubMed and United States' National Library of Medicine databases. We reviewed around 50 papers but referenced only 30 for this article. The literature review provided us a new insight regarding safety of mesh. Polypropylene mesh is safe for vaginal surgery if used by experienced surgeons. The safety of mesh becomes compromised in the hands of commercial surgical kit providers. All the new mesh tailored kits should undergo evidence-based trials and then can be safely used worldwide.

Large accumulation of micro-sized synthetic polymer particles in the sea surface microlayer.

PubMed

Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Kang, Jung-Hoon; Kwon, Oh Youn; Han, Gi Myung; Shim, Won Joon

2014-08-19

Determining the exact abundance of microplastics on the sea surface can be susceptible to the sampling method used. The sea surface microlayer (SML) can accumulate light plastic particles, but this has not yet been sampled. The abundance of microplastics in the SML was evaluated off the southern coast of Korea. The SML sampling method was then compared to bulk surface water filtering, a hand net (50 μm mesh), and a Manta trawl net (330 μm mesh). The mean abundances were in the order of SML water > hand net > bulk water > Manta trawl net. Fourier transform infrared spectroscopy (FTIR) identified that alkyds and poly(acrylate/styrene) accounted for 81 and 11%, respectively, of the total polymer content of the SML samples. These polymers originated from paints and the fiber-reinforced plastic (FRP) matrix used on ships. Synthetic polymers from ship coatings should be considered to be a source of microplastics. Selecting a suitable sampling method is crucial for evaluating microplastic pollution.

The Role of Synthetic and Biologic Materials in the Treatment of Pelvic Organ Prolapse

PubMed Central

Brown, Ramon A.; Ellis, C. Neal

2014-01-01

Pelvic organ prolapse is a significant medical problem that poses a diagnostic and management dilemma. These diseases cause serious morbidity in those affected and treatment is sought for relief of pelvic pain, rectal bleeding, chronic constipation, obstructed defecation, and fecal incontinence. Numerous procedures have been proposed to treat these conditions; however, the search continues as colorectal surgeons attempt to find the procedure that would optimally treat these conditions. The use of prosthetics in the repair of pelvic organ prolapse has become prevalent as the benefits of their use are realized. While advances in biologic mesh and new surgical techniques promise improved functional outcomes with decreased complication rates without de novo symptoms, the debate concerning the best prosthetic material, synthetic or biologic, remains controversial. Furthermore, laparoscopic ventral mesh rectopexy has emerged as a procedure that could potentially fill this role and is rapidly becoming the procedure of choice for the surgical treatment of pelvic organ prolapse. PMID:25435827

The role of synthetic and biologic materials in the treatment of pelvic organ prolapse.

PubMed

Brown, Ramon A; Ellis, C Neal

2014-12-01

Pelvic organ prolapse is a significant medical problem that poses a diagnostic and management dilemma. These diseases cause serious morbidity in those affected and treatment is sought for relief of pelvic pain, rectal bleeding, chronic constipation, obstructed defecation, and fecal incontinence. Numerous procedures have been proposed to treat these conditions; however, the search continues as colorectal surgeons attempt to find the procedure that would optimally treat these conditions. The use of prosthetics in the repair of pelvic organ prolapse has become prevalent as the benefits of their use are realized. While advances in biologic mesh and new surgical techniques promise improved functional outcomes with decreased complication rates without de novo symptoms, the debate concerning the best prosthetic material, synthetic or biologic, remains controversial. Furthermore, laparoscopic ventral mesh rectopexy has emerged as a procedure that could potentially fill this role and is rapidly becoming the procedure of choice for the surgical treatment of pelvic organ prolapse.

Development of a model for occipital fixation--validation of an analogue bone material.

PubMed

Mullett, H; O'Donnell, T; Felle, P; O'Rourke, K; FitzPatrick, D

2002-01-01

Several implant systems may be used to fuse the skull to the upper cervical spine (occipitocervical fusion). Current biomechanical evaluation is restricted by the limitations of human cadaveric specimens. This paper describes the design and validation of a synthetic testing model of the occipital bone. Data from thickness measurement and pull-out strength testing of a series of human cadaveric skulls was used in the design of a high-density rigid polyurethane foam model. The synthetic occipital model demonstrated repeatable and consistent morphological and biomechanical properties. The model provides a standardized environment for evaluation of occipital implants.

Toward An Unstructured Mesh Database

NASA Astrophysics Data System (ADS)

Rezaei Mahdiraji, Alireza; Baumann, Peter Peter

2014-05-01

Unstructured meshes are used in several application domains such as earth sciences (e.g., seismology), medicine, oceanography, cli- mate modeling, GIS as approximate representations of physical objects. Meshes subdivide a domain into smaller geometric elements (called cells) which are glued together by incidence relationships. The subdivision of a domain allows computational manipulation of complicated physical structures. For instance, seismologists model earthquakes using elastic wave propagation solvers on hexahedral meshes. The hexahedral con- tains several hundred millions of grid points and millions of hexahedral cells. Each vertex node in the hexahedrals stores a multitude of data fields. To run simulation on such meshes, one needs to iterate over all the cells, iterate over incident cells to a given cell, retrieve coordinates of cells, assign data values to cells, etc. Although meshes are used in many application domains, to the best of our knowledge there is no database vendor that support unstructured mesh features. Currently, the main tool for querying and manipulating unstructured meshes are mesh libraries, e.g., CGAL and GRAL. Mesh li- braries are dedicated libraries which includes mesh algorithms and can be run on mesh representations. The libraries do not scale with dataset size, do not have declarative query language, and need deep C++ knowledge for query implementations. Furthermore, due to high coupling between the implementations and input file structure, the implementations are less reusable and costly to maintain. A dedicated mesh database offers the following advantages: 1) declarative querying, 2) ease of maintenance, 3) hiding mesh storage structure from applications, and 4) transparent query optimization. To design a mesh database, the first challenge is to define a suitable generic data model for unstructured meshes. We proposed ImG-Complexes data model as a generic topological mesh data model which extends incidence graph model to multi-incidence relationships. We instrument ImG model with sets of optional and application-specific constraints which can be used to check validity of meshes for a specific class of object such as manifold, pseudo-manifold, and simplicial manifold. We conducted experiments to measure the performance of the graph database solution in processing mesh queries and compare it with GrAL mesh library and PostgreSQL database on synthetic and real mesh datasets. The experiments show that each system perform well on specific types of mesh queries, e.g., graph databases perform well on global path-intensive queries. In the future, we investigate database operations for the ImG model and design a mesh query language.

Controlling the error on target motion through real-time mesh adaptation: Applications to deep brain stimulation.

PubMed

Bui, Huu Phuoc; Tomar, Satyendra; Courtecuisse, Hadrien; Audette, Michel; Cotin, Stéphane; Bordas, Stéphane P A

2018-05-01

An error-controlled mesh refinement procedure for needle insertion simulations is presented. As an example, the procedure is applied for simulations of electrode implantation for deep brain stimulation. We take into account the brain shift phenomena occurring when a craniotomy is performed. We observe that the error in the computation of the displacement and stress fields is localised around the needle tip and the needle shaft during needle insertion simulation. By suitably and adaptively refining the mesh in this region, our approach enables to control, and thus to reduce, the error whilst maintaining a coarser mesh in other parts of the domain. Through academic and practical examples we demonstrate that our adaptive approach, as compared with a uniform coarse mesh, increases the accuracy of the displacement and stress fields around the needle shaft and, while for a given accuracy, saves computational time with respect to a uniform finer mesh. This facilitates real-time simulations. The proposed methodology has direct implications in increasing the accuracy, and controlling the computational expense of the simulation of percutaneous procedures such as biopsy, brachytherapy, regional anaesthesia, or cryotherapy. Moreover, the proposed approach can be helpful in the development of robotic surgeries because the simulation taking place in the control loop of a robot needs to be accurate, and to occur in real time. Copyright © 2018 John Wiley & Sons, Ltd.

[Hernia surgery in urology. Part 2: parastomal, trocar and incisional hernias - fundamentals of clinical diagnostics and treatment].

PubMed

Franz, T; Schwalenberg, T; Dietrich, A; Müller, J; Stolzenburg, J-U

2013-06-01

Hernias are a common occurrence with a correspondingly huge clinical and economic impact on the healthcare system. Parastomal and trocar hernias are rare in routine urological work. The therapy of parastomal hernias remains problematic but basically the surgeon is able to use conventional techniques with suture repair or procedures with mesh implantation. The conventional parastomal hernia repair with mesh can be classified into sublay, onlay and intraperitoneal techniques. Furthermore, a relocation of the stoma is possible. Trocar hernias represent a rare but hazardous complication. Due to the increase in keyhole surgery there is also the danger of a rise in their occurrence. Incisional hernias occur frequently in patients who have undergone laparotomy and for repair different surgical techniques and types of meshes are available. This article presents an overview of the epidemiology, pathogenesis, clinical symptoms, diagnostic and therapy of parastomal, trocar and incisional hernias.

[Complications associated with the use of polypropylene mesh in women under colposacropexy].

PubMed

Aguilera-Maldonado, Lizzete Verónica; Jiménez-Vieyra, Carlos Ramón; Solís-Moreno, Tania Kristal

2015-10-01

There have been numerous surgical procedures and modi fied in the hope of obtaining a lasting cure for pelvic organ prolapse These surgeries were performed using the traditionally native tissues of the patient. In an effort to reduce morbidity, improve surgical outcomes and reduce the complexity of these operations, we used a growing number of synthetic mesh repairs and biomaterials used tissue from cadaver or animal. To evaluate the frequency of complications associated with the use of polypropylene mesh in women undergoing colposacropexy. Retrospective, observational and descriptive study conducted at the Hospitalde Ginecología y Obstetricia 3 IMSS (Mexico) between 1 January 2006 and 15 February 2013. The main risk factors associated with pelvic organ prolapse were considered, comorbidity and complications directly linked to the procedure. With respect to the related complications colposacropexy procedure using polypropylene mesh were documented in 20 of 67 patients which corresponded to 30%. A number of complications have been associated with the use of meshes between these include: extrusion, erosion, pelvic pain, dyspareunia, bladder or bowel condition, but one aspect is poorly evaluated sexual dysfunction without to definitely plays an important role in the field bio-psychosocial.

Synthetic matrix of polyether-polyurethane as a biological platform for pancreatic regeneration.

PubMed

Pereira, Luciana Xavier; Viana, Celso Tarso Rodrigues; Orellano, Laura Alejandra Ariza; Almeida, Simone Aparecida; Vasconcelos, Anilton Cesar; Goes, Alfredo de Miranda; Birbrair, Alexander; Andrade, Silvia Passos; Campos, Paula Peixoto

2017-05-01

Several alternative cellular approaches using biomaterials to host insulin-producing cells derived from stem cells have been developed to overcome the limitations of type 1 diabetes treatment (exogenous insulin injection). However, none seem to fulfill all requirements needed to induce pancreatic cells successful colonization of the scaffolds. Here, we report a polymeric platform adherent to the native mice pancreas filled with human adipose stem cells (hASCs) that was able to induce growth of pancreatic parenchyma. Synthetic polyether-polyurethane discs were placed adjacent to pancreas of normoglycemic and streptozotocin-induced diabetic mice. At day 4 post implantation, 1×10 6 hASCs were injected intra-implant in groups of normoglycemic and diabetic mice. Immunohistochemistry analysis of the implants was performed to identify insulin positive cells in the newly formed tissue. In addition, metabolic, inflammatory and angiogenic parameters were carried out in those mice. This study provides evidence of the ability of a biohybrid device to induce the growth of differentiated pancreas parenchyma in both normoglycemic and streptozotocin-induced diabetic mice as detected by histological analysis. Glucose metabolism and body weight of hyperglycemic mice bearing hASCs implants improved. The synthetic porous scaffold bearing hASC cells placed adjacent to the native animal pancreas exhibits the potential to be exploited in future cell-based type 1 diabetes therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Photonic modes in synthetic photonic lattices localized due to nontrivial gauge field circulation

NASA Astrophysics Data System (ADS)

Pankov, Artem; Vatnik, Ilya; Churkin, Dmitry; Sukhorukov, Andrey A.

2017-10-01

One of concepts giving opportunities for studying of topological insulators in non-magnetic materials, or creating scattering-immune in optical waveguides is creation of synthetic gauge fields in photonic systems. It was shown that gauge fields shift the band-gaps of optical waves, which can be applied to implement one-way nonreciprocal waveguides, even though both the waveguide core and cladding are in a topologically trivial state [1]. In our work we propose a method to create a gauge field in a synthetic photonic mesh lattice - an optical device proved its high versatility for optical experiments [2]. We demonstrate presence of localized modes due to nontrivial gauge field circulation.

Biaxial Mechanical Evaluation of Absorbable and Nonabsorbable Synthetic Surgical Meshes Used for Hernia Repair: Physiological Loads Modify Anisotropy Response.

PubMed

Cordero, A; Hernández-Gascón, B; Pascual, G; Bellón, J M; Calvo, B; Peña, E

2016-07-01

The aim of this study was to obtain information about the mechanical properties of six meshes commonly used for hernia repair (Surgipro(®), Optilene(®), Infinit(®), DynaMesh(®), Ultrapro™ and TIGR(®)) by planar biaxial tests. Stress-stretch behavior and equibiaxial stiffness were evaluated, and the anisotropy was determined by testing. In particular, equibiaxial test (equal simultaneous loading in both directions) and biaxial test (half of the load in one direction following the Laplace law) were selected as a representation of physiologically relevant loads. The majority of the meshes displayed values in the range of 8 and 18 (N/mm) in each direction for equibiaxial stiffness (tangent modulus under equibiaxial load state in both directions), while a few achieved 28 and 50 (N/mm) (Infinit (®) and TIGR (®)). Only the Surgipro (®) mesh exhibited planar isotropy, with similar mechanical properties regardless of the direction of loading, and an anisotropy ratio of 1.18. Optilene (®), DynaMesh (®), Ultrapro (®) and TIGR (®) exhibited moderate anisotropy with ratios of 1.82, 1.84, 2.17 and 1.47, respectively. The Infinit (®) scaffold exhibited very high anisotropy with a ratio of 3.37. These trends in material anisotropic response changed during the physiological state in the human abdominal wall, i.e. T:0.5T test, which the meshes were loaded in one direction with half the load used in the other direction. The Surgipro (®) mesh increased its anisotropic response (Anis[Formula: see text] = 0.478) and the materials that demonstrated moderate and high anisotropic responses during multiaxial testing presented a quasi-isotropic response, especially the Infinit(®) mesh that decreased its anisotropic response from 3.369 to 1.292.

Comparison of three different methods for effective introduction of platelet-rich plasma on PLGA woven mesh.

PubMed

Lee, Ji-Hye; Nam, Jinwoo; Kim, Hee Joong; Yoo, Jeong Joon

2015-03-11

For successful tissue regeneration, effective cell delivery to defect site is very important. Various types of polymer biomaterials have been developed and applied for effective cell delivery. PLGA (poly lactic-co-glycolic acid), a synthetic polymer, is a commercially available and FDA approved material. Platelet-rich plasma (PRP) is an autologous growth factor cocktail containing various growth factors including PDGF, TGFβ-1 and BMPs, and has shown positive effects on cell behaviors. We hypothesized that PRP pretreatment on PLGA mesh using different methods would cause different patterns of platelet adhesion and stages which would modulate cell adhesion and proliferation on the PLGA mesh. In this study, we pretreated PRP on PLGA using three different methods including simple dripping (SD), dynamic oscillation (DO) and centrifugation (CE), then observed the amount of adhered platelets and their activation stage distribution. The highest amount of platelets was observed on CE mesh and calcium treated CE mesh. Moreover, calcium addition after PRP coating triggered dramatic activation of platelets which showed large and flat morphologies of platelets with rich fibrin networks. Human chondrocytes (hCs) and human bone marrow stromal cells (hBMSCs) were next cultured on PRP-pretreated PLGA meshes using different preparation methods. CE mesh showed a significant increase in the initial cell adhesion of hCs and proliferation of hBMSCs compared with SD and DO meshes. The results demonstrated that the centrifugation method can be considered as a promising coating method to introduce PRP on PLGA polymeric material which could improve cell-material interaction using a simple method.

A New Cross-By-Pass-Torus Architecture Based on CBP-Mesh and Torus Interconnection for On-Chip Communication.

PubMed

Gulzari, Usman Ali; Sajid, Muhammad; Anjum, Sheraz; Agha, Shahrukh; Torres, Frank Sill

2016-01-01

A Mesh topology is one of the most promising architecture due to its regular and simple structure for on-chip communication. Performance of mesh topology degraded greatly by increasing the network size due to small bisection width and large network diameter. In order to overcome this limitation, many researchers presented modified Mesh design by adding some extra links to improve its performance in terms of network latency and power consumption. The Cross-By-Pass-Mesh was presented by us as an improved version of Mesh topology by intelligent addition of extra links. This paper presents an efficient topology named Cross-By-Pass-Torus for further increase in the performance of the Cross-By-Pass-Mesh topology. The proposed design merges the best features of the Cross-By-Pass-Mesh and Torus, to reduce the network diameter, minimize the average number of hops between nodes, increase the bisection width and to enhance the overall performance of the network. In this paper, the architectural design of the topology is presented and analyzed against similar kind of 2D topologies in terms of average latency, throughput and power consumption. In order to certify the actual behavior of proposed topology, the synthetic traffic trace and five different real embedded application workloads are applied to the proposed as well as other competitor network topologies. The simulation results indicate that Cross-By-Pass-Torus is an efficient candidate among its predecessor's and competitor topologies due to its less average latency and increased throughput at a slight cost in network power and energy for on-chip communication.

Communication Intervention for Children with Cochlear Implants: Two Case Studies.

ERIC Educational Resources Information Center

Ertmer, David J.; Leonard, Jeannette S.; Pachuilo, Michael L.

2002-01-01

This article describes the intervention programs attended and progress made by two children (ages 3 and 7) who exhibited considerable differences in benefit from their cochlear implants. Their intervention programs employed both analytical and synthetic auditory training and emphasized the development of speech production and language skills.…

Preclinical animal study and human clinical trial data of co-electrospun poly(l-lactide-co-caprolactone) and fibrinogen mesh for anterior pelvic floor reconstruction

PubMed Central

Wu, Xujun; Wang, Yuru; Zhu, Cancan; Tong, Xiaowen; Yang, Ming; Yang, Li; Liu, Zhang; Huang, Weihong; Wu, Feng; Zong, Honghai; Li, Huaifang; He, Hongbing

2016-01-01

Synthetic and biological materials are commonly used for pelvic floor reconstruction. In this study, host tissue response and biomechanical properties of mesh fabricated from co-electrospun poly(l-lactide-co-caprolactone) (PLCL) and fibrinogen (Fg) were compared with those of polypropylene mesh (PPM) in a canine abdominal defect model. Macroscopic, microscopic, histological, and biomechanical evaluations were performed over a 24-week period. The results showed that PLCL/Fg mesh had similar host tissue responses but better initial vascularization and graft site tissue organization than PPM. The efficacy of the PLCL/Fg mesh was further examined in human pelvic floor reconstruction. Operation time, intraoperative blood loss, and pelvic organ prolapse quantification during 6-month follow-up were compared for patients receiving PLCL/Fg mesh versus PPM. According to the pelvic organ prolapse quantification scores, the anterior vaginal wall 3 cm proximal to the hymen point (Aa point), most distal edge of the cervix or vaginal cuff scar point (C point), and posterior fornix point (D point) showed significant improvement (P<0.01) at 1, 3, and 6 months for both groups compared with preoperatively. At 6 months, improvements at the Aa point in the PLCL/Fg group were significantly more (P<0.005) than the PPM group, indicating that, while both materials improve the patient symptoms, PLCL/Fg mesh resulted in more obvious improvement. PMID:26893556

Magnesium Based Materials and their Antimicrobial Activity

NASA Astrophysics Data System (ADS)

Robinson, Duane Allan

The overall goals of this body of work were to characterize the antimicrobial properties of magnesium (Mg) metal and nano-magnesium oxide (nMgO) in vitro, to evaluate the in vitro cytotoxicity of Mg metal, and to incorporate MgO nanoparticles into a polymeric implant coating and evaluate its in vitro antimicrobial properties. In the course of this work it was found that Mg metal, Mg-mesh, and nMgO have in vitro antimicrobial properties that are similar to a bactericidal antibiotic. For Mg metal, the mechanism of this activity appears to be related to an increase in pH (i.e. a more alkaline environment) and not an increase in Mg2+. Given that Mg-mesh is a Mg metal powder, the assumption is that it has the same mechanism of activity as Mg metal. The mechanism of activity for nMgO remains to be elucidated and may be related to a combination of interaction of the nanoparticles with the bacteria and the alkaline pH. It was further demonstrated that supernatants from suspensions of Mg-mesh and nMgO had the same antimicrobial effect as was noted when the particles were used. The supernatant from Mg-mesh and nMgO was also noted to prevent biofilm formation for two Staphylococcus strains. Finally, poly-epsilon-caprolactone (PCL) composites of Mg-mesh (PCL+Mg-mesh) and nMgO (PCL+nMgO) were produced. Coatings applied to screws inhibited growth of Escherichia coli and Pseudomonas aeruginosa and in thin disc format inhibited the growth of Staphylococcus aureus in addition to the E. coli and P. aeruginosa. Pure Mg metal was noted to have some cytotoxic effect on murine fibroblast and osteoblast cell lines, although this effect needs to be characterized further. To address the need for an in vivo model for evaluating implant associated infections, a new closed fracture osteomyelitis model in the femur of the rat was developed. Magnesium, a readily available and inexpensive metal was shown to have antimicrobial properties that appear to be related to its corrosion products and that nMgO has similar effects. Incorporation of nMgO into a PCL composite was easily achieved and revealed similar, although not identical antimicrobial results. This work has provided a strong foundation and methodology for further evaluation of Mg based materials and their antimicrobial properties.

29 CFR 1910.184 - Slings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope (conventional three strand... steel chain sling or wire rope sling. (See Fig. N-184-3.) Mechanical coupling link is a nonwelded... Slings 6×19 and 6×37 Classification Improved Plow Steel Grade Rope With Independent Wire Rope Core (IWRC...

29 CFR 1910.184 - Slings.

Code of Federal Regulations, 2011 CFR

2011-07-01

... alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope (conventional three strand... steel chain sling or wire rope sling. (See Fig. N-184-3.) Mechanical coupling link is a nonwelded... Slings 6×19 and 6×37 Classification Improved Plow Steel Grade Rope With Independent Wire Rope Core (IWRC...

Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.

PubMed

Lu, Zhen; McKellop, Harry A

2014-03-01

This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3 mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3 mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5 mm than Methods 1-4 with a point spacing of 3 mm.

Clinical outcome of alveolar ridge augmentation with individualized CAD-CAM-produced titanium mesh.

PubMed

Sagheb, K; Schiegnitz, E; Moergel, M; Walter, C; Al-Nawas, B; Wagner, W

2017-12-01

The augmentation of the jaw has been and continues to be a sophisticated therapy in implantology. Modern CAD-CAM technologies lead to revival of old and established augmentation techniques such as the use of titanium mesh (TM) for bone augmentation. The aim of this retrospective study was to evaluate the clinical outcome of an individualized CAD-CAM-produced TM based on the CT/DVT-DICOM data of the patients for the first time. In 17 patients, 21 different regions were augmented with an individualized CAD-CAM-produced TM (Yxoss CBR®, Filderstadt, Germany). For the augmentation, a mixture of autologous bone and deproteinized bovine bone mineral (DBBM) or autologous bone alone was used. Reentry with explantation of the TM and simultaneous implantation of 44 implants were performed after 6 months. Preoperative and 6-month postoperative cone beam computed tomographies (CBCT) were performed to measure the gained bone height. The success rate for the bone grafting procedure was 100%. Thirty-three percent of cases presented an exposure of the TM during the healing period. However, premature removal of these exposed meshes was not necessary. Exposure rate in augmentations performed with mid-crestal incisions was higher than in augmentations performed with a modified poncho incision (45.5 vs. 20%, p = 0.221). In addition, exposure rates in the maxilla were significantly higher than in the mandible (66.7 vs. 8.3%, p = 0.009). Gender, smoking, periodontal disease, gingiva type, used augmentation material, and used membrane had no significant influence on the exposure rate (p > 0.05). The mean vertical augmentation was 6.5 ± 1.7 mm, and the mean horizontal augmentation was 5.5 ± 1.9 mm. Implant survival rate after a mean follow-up of 12 ± 6 months after reentry was 100%. Within the limits of the retrospective character of this study, this study shows for the first time that individualized CAD-CAM TM provide a sufficient and safe augmentation technique, especially for vertical and combined defects. However, the soft tissue handling for sufficient mesh covering remains one of the most critical steps using this technique.

The dynamic natures of implant loading.

PubMed

Wang, Rui-Feng; Kang, Byungsik; Lang, Lisa A; Razzoog, Michael E

2009-06-01

A fundamental problem in fully understanding the dynamic nature of implant loading is the confusion that exists regarding the torque load delivered to the implant complex, the initial force transformation/stress/strain developed within the system during the implant complex assembly, and how the clamping forces at the interfaces and the preload stress impact the implant prior to any external loading. The purpose of this study was to create an accurately dimensioned finite element model with spiral threads and threaded bores included in the implant complex, positioned in a bone model, and to determine the magnitude and distribution of the force transformation/stress/strain patterns developed in the modeled implant system and bone and, thus, provide the foundational data for the study of the dynamic loading of dental implants prior to any external loading. An implant (Brånemark Mark III), abutment (CeraOne), abutment screw (Unigrip), and the bone surrounding the implant were modeled using HyperMesh software. The threaded interfaces between screw/implant and implant/bone were designed as a spiral thread helix assigned with specific coefficient of friction values. Assembly simulation using ABAQUS and LS-DYNA was accomplished by applying a 32-Ncm horizontal torque load on the abutment screw (Step 1), then decreasing the torque load to 0 Ncm to simulate the wrench removal (Step 2). The postscript data were collected and reviewed by HyperMesh. A regression analysis was used to depict the relationships between the torque load and the mechanical parameters. During the 32-Ncm tightening sequence, the abutment screw elongated 13.3 mum. The tightening torque generated a 554-N clamping force at the abutment/implant interface and a 522-N preload. The von Mises stress values were 248 MPa in the abutment at the abutment-implant interface, 765 MPa at the top of the screw shaft, 694 MPa at the bottom of the screw shaft, 1365 MPa in the top screw thread, and 21 MPa in the bone at the top of the implant-bone interface. This study also identified various characteristic isosurface stress patterns. The maximum stress magnitude to complete the von Mises stress joint pattern in the present model was 107 MPa during screw tightening, and was reduced to 104 MPa with removal of the wrench. Various specific stress patterns were identified within all elements of the implant complex during the assembly simulation. During the torque moment application, the abutment screw was elongated, and every 1.0-mum elongation of the screw was equivalent to a 47.9-N increase of the preload in the implant complex. The ideal index to determine the preload amount was the contact force at the interface between the screw threads and the threaded screw bore. The isosurface mode identified various characteristic stress patterns developed within the implant complex at the various interfaces during the assembly simulation. These patterns are the (1) spiral and ying-yang pattern of the XY stress, (2) spring, cap, clamping, and preload pattern of the ZZ stress, and (3) bone holding and joint pattern of the von Mises stress.

Engineering emergent multicellular behavior through synthetic adhesion

NASA Astrophysics Data System (ADS)

Glass, David; Riedel-Kruse, Ingmar

In over a decade, synthetic biology has developed increasingly robust gene networks within single cells, but constructed very few systems that demonstrate multicellular spatio-temporal dynamics. We are filling this gap in synthetic biology's toolbox by developing an E. coli self-assembly platform based on modular cell-cell adhesion. We developed a system in which adhesive selectivity is provided by a library of outer membrane-displayed peptides with intra-library specificities, while affinity is provided by consistent expression across the entire library. We further provide a biophysical model to help understand the parameter regimes in which this tool can be used to self-assemble into cellular clusters, filaments, or meshes. The combined platform will enable future development of synthetic multicellular systems for use in consortia-based metabolic engineering, in living materials, and in controlled study of minimal multicellular systems. Stanford Bio-X Bowes Fellowship.

4D cone-beam CT reconstruction using multi-organ meshes for sliding motion modeling

NASA Astrophysics Data System (ADS)

Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing

2016-02-01

A simultaneous motion estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the motion fields. The objective of this work is to improve the computation efficiency and motion estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing model. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and motion. Additionally, the discontinuity in the motion fields between different organs during respiration was explicitly considered in the multi-organ mesh model. This will help with the accurate visualization and motion estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding motion phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp-Davis-Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations.

4D cone-beam CT reconstruction using multi-organ meshes for sliding motion modeling.

PubMed

Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing

2016-02-07

A simultaneous motion estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the motion fields. The objective of this work is to improve the computation efficiency and motion estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing model. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and motion. Additionally, the discontinuity in the motion fields between different organs during respiration was explicitly considered in the multi-organ mesh model. This will help with the accurate visualization and motion estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding motion phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp-Davis-Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations.

Vaginal mucosal flap as a sling preservation for the treatment of vaginal exposure of mesh.

PubMed

Kim, Sea Young; Park, Jong Yeon; Kim, Han Kwon; Park, Chang Hoo; Kim, Sung Jin; Sung, Gi Teck; Park, Chang Myon

2010-06-01

Tension-free vaginal tape (TVT) procedures are used for the treatment of stress urinary incontinence in women. The procedures with synthetic materials can have a risk of vaginal erosion. We experienced transobturator suburethral sling (TOT) tape-induced vaginal erosion and report the efficacy of a vaginal mucosal covering technique. A total of 560 female patients diagnosed with stress urinary incontinence underwent TOT procedures at our hospital between January 2005 and August 2009. All patients succeeded in follow-ups, among which 8 patients (mean age: 50.5 years) presented with vaginal exposure of the mesh. A vaginal mucosal covering technique was performed under local anesthesia after administration of antibiotics and vaginal wound dressings for 3-4 days. Seven of the 8 patients complained of persistent vaginal discharge postoperatively. Two of the 8 patients complained of dyspareunia of their male partners. The one remaining patient was otherwise asymptomatic, but mesh erosion was discovered at the routine follow-up visit. Six of the 8 patients showed complete mucosal covering of the mesh after the operation (mean follow-up period: 16 moths). Vaginal mucosal erosion recurred in 2 patients, and the mesh was then partially removed. One patient had recurrent stress urinary incontinence. Vaginal mucosal covering as a sling preservation with continued patient continence may be a feasible and effective option for the treatment of vaginal exposure of mesh after TOT tape procedures.

4D cone-beam CT reconstruction using multi-organ meshes for sliding motion modeling

PubMed Central

Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing

2016-01-01

A simultaneous motion estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the motion fields. The objective of this work is to improve the computation efficiency and motion estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing model. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and motion. Additionally, the discontinuity in the motion fields between different organs during respiration was explicitly considered in the multi-organ mesh model. This will help with the accurate visualization and motion estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding motion phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp–Davis–Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations. PMID:26758496

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duchaineau, M.; Wolinsky, M.; Sigeti, D.E.

Terrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor stimulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly, and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame. Our method, dubbed Real-time Optimally Adaptingmore » Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from pre-processed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and priority-computation deferral lists. ROAM execution time is proportionate to the number of triangle changes per frame, which is typically a few percent of the output mesh size, hence ROAM performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.« less

The potential role of bioengineering and three-dimensional printing in curing global corneal blindness.

PubMed

Ludwig, Parker E; Huff, Trevor J; Zuniga, Jorge M

2018-01-01

An insufficiency of accessible allograft tissue for corneal transplantation leaves many impaired by untreated corneal disease. There is promise in the field of regenerative medicine for the development of autologous corneal tissue grafts or collagen-based scaffolds. Another approach is to create a suitable corneal implant that meets the refractive needs of the cornea and is integrated into the surrounding tissue but does not attempt to perfectly mimic the native cornea on a cellular level. Materials that have been investigated for use in the latter concept include natural polymers such as gelatin, semisynthetic polymers like gelatin methacrylate, and synthetic polymers. There are advantages and disadvantages inherent in natural and synthetic polymers: natural polymers are generally more biodegradable and biocompatible, while synthetic polymers typically provide greater control over the characteristics or property adjustment of the materials. Additive manufacturing could aid in the precision production of keratoprostheses and the personalization of implants.

The potential role of bioengineering and three-dimensional printing in curing global corneal blindness

PubMed Central

Ludwig, Parker E; Huff, Trevor J; Zuniga, Jorge M

2018-01-01

An insufficiency of accessible allograft tissue for corneal transplantation leaves many impaired by untreated corneal disease. There is promise in the field of regenerative medicine for the development of autologous corneal tissue grafts or collagen-based scaffolds. Another approach is to create a suitable corneal implant that meets the refractive needs of the cornea and is integrated into the surrounding tissue but does not attempt to perfectly mimic the native cornea on a cellular level. Materials that have been investigated for use in the latter concept include natural polymers such as gelatin, semisynthetic polymers like gelatin methacrylate, and synthetic polymers. There are advantages and disadvantages inherent in natural and synthetic polymers: natural polymers are generally more biodegradable and biocompatible, while synthetic polymers typically provide greater control over the characteristics or property adjustment of the materials. Additive manufacturing could aid in the precision production of keratoprostheses and the personalization of implants. PMID:29686829

Adherence to best practice consensus guidelines for implant-based breast reconstruction: Results from the iBRA national practice questionnaire survey.

PubMed

Mylvaganam, Senthurun; Conroy, Elizabeth J; Williamson, Paula R; Barnes, Nicola L P; Cutress, Ramsey I; Gardiner, Matthew D; Jain, Abhilash; Skillman, Joanna M; Thrush, Steven; Whisker, Lisa J; Blazeby, Jane M; Potter, Shelley; Holcombe, Christopher

2018-05-01

The 2008 National Mastectomy and Breast Reconstruction Audit demonstrated marked variation in the practice and outcomes of breast reconstruction in the UK. To standardise practice and improve outcomes for patients, the British professional associations developed best-practice guidelines with specific guidance for newer mesh-assisted implant-based techniques. We explored the degree of uptake of best-practice guidelines within units performing implant-based reconstruction (IBBR) as the first phase of the implant Breast Reconstruction Evaluation (iBRA) study. A questionnaire developed by the iBRA Steering Group was completed by trainee and consultant leads at breast and plastic surgical units across the UK. Simple summary statistics were calculated for each survey item to assess compliance with current best-practice guidelines. 81 units from 79 NHS Trusts completed the questionnaire. Marked variation was observed in adherence to guidelines, especially those relating to clinical governance and infection prevention strategies. Less than half (n = 28, 47%) of units obtained local clinical governance board approval prior to offering new mesh-based techniques and prospective audit of the clinical, cosmetic and patient-reported outcomes of surgery was infrequent. Most units screened for methicillin-resistant staphylococcus aureus prior to surgery but fewer than 1 in 3 screened for methicillin-sensitive strains. Laminar-flow theatres (recommended for IBBR) were not widely-available with less than 1 in 5 units having regular access. Peri-operative antibiotics were widely-used, but the type and duration were highly-variable. The iBRA national practice questionnaire has demonstrated variation in reported practice and adherence to IBBR guidelines. High-quality evidence is urgently required to inform best practice. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Mechanical testing of implant properties of thoracoscopic implantation of ventral spinal stabilizing systems. Comparative study with the ISO/DIS 12189-2 corpectomy model and an improved synthetic model].

PubMed

Grupp, T M; Beisse, R; Potulski, M; Marnay, T; Beger, J; Blömer, W

2002-04-01

A new modular anterior fixation system MACS TL (modular anterior construct system for the thoracic and lumbar spine) has been developed for use in thoracoscopic spondylodesis. This system demonstrates high angular stability and meets the surgical requirements for an endoscopic approach. The objective of the current study was fatigue testing of the MACS TL implant system using a corpectomy model according to ISO/DIS 12189-2 and a synthetic model recently developed by Kotani et al. [6]. The MACS TL system demonstrated good mechanical properties with a high stiffness compared to the published data reviewed. The importance of dynamic testing in a corpectomy model has been demonstrated by comparing the MACS TL plate system with an early prototype, which has not yet been clinically evaluated. The corpectomy model according to Kotani et al. offers an interesting alternative to the ISO/DIS 12189-2 test method for asymmetrically designed and antero-laterally positioned spinal implants due to the unconstrained ball joint.

Mesh, graft, or standard repair for women having primary transvaginal anterior or posterior compartment prolapse surgery: two parallel-group, multicentre, randomised, controlled trials (PROSPECT).

PubMed

Glazener, Cathryn Ma; Breeman, Suzanne; Elders, Andrew; Hemming, Christine; Cooper, Kevin G; Freeman, Robert M; Smith, Anthony Rb; Reid, Fiona; Hagen, Suzanne; Montgomery, Isobel; Kilonzo, Mary; Boyers, Dwayne; McDonald, Alison; McPherson, Gladys; MacLennan, Graeme; Norrie, John

2017-01-28

The use of transvaginal mesh and biological graft material in prolapse surgery is controversial and has led to a number of enquiries into their safety and efficacy. Existing trials of these augmentations are individually too small to be conclusive. We aimed to compare the outcomes of prolapse repair involving either synthetic mesh inlays or biological grafts against standard repair in women. We did two pragmatic, parallel-group, multicentre, randomised controlled trials for our study (PROSPECT [PROlapse Surgery: Pragmatic Evaluation and randomised Controlled Trials]) in 35 centres (a mix of secondary and tertiary referral hospitals) in the UK. We recruited women undergoing primary transvaginal anterior or posterior compartment prolapse surgery by 65 gynaecological surgeons in these centres. We randomly assigned participants by a remote web-based randomisation system to one of the two trials: comparing standard (native tissue) repair alone with standard repair augmented with either synthetic mesh (the mesh trial) or biological graft (the graft trial). We assigned women (1:1:1 or 1:1) within three strata: assigned to one of the three treatment options, comparison of standard repair with mesh, and comparison of standard repair with graft. Participants, ward staff, and outcome assessors were masked to randomisation where possible; masking was obviously not possible for the surgeon. Follow-up was for 2 years after the surgery; the primary outcomes, measured at 1 year and 2 years, were participant-reported prolapse symptoms (i.e. the Pelvic Organ Prolapse Symptom Score [POP-SS]) and condition-specific (ie, prolapse-related) quality-of-life scores, analysed in the modified intention-to-treat population. This trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN60695184. Between Jan 8, 2010, and Aug 30, 2013, we randomly allocated 1352 women to treatment, of whom 1348 were included in the analysis. 865 women were included in the mesh trial (430 to standard repair alone, 435 to mesh augmentation) and 735 were included in the graft trial (367 to standard repair alone, 368 to graft augmentation). Because the analyses were carried out separately for each trial (mesh trial and graft trial) some women in the standard repair arm assigned to all treatment options were included in the standard repair group of both trials. 23 of these women did not receive any surgery (15 in the mesh trial, 13 in the graft trial; five were included in both trials) and were included in the baseline analyses only. Mean POP-SS at 1 year did not differ substantially between comparisons (standard 5·4 [SD 5·5] vs mesh 5·5 [5·1], mean difference 0·00, 95% CI -0·70 to 0·71; p=0·99; standard 5·5 [SD 5·6] vs graft 5·6 [5·6]; mean difference -0·15, -0·93 to 0·63; p=0·71). Mean prolapse-related quality-of-life scores also did not differ between groups at 1 year (standard 2·0 [SD 2·7] vs mesh 2·2 [2·7], mean difference 0·13, 95% CI -0·25 to 0·51; p=0·50; standard 2·2 [SD 2·8] vs graft 2·4 [2·9]; mean difference 0·13, -0·30 to 0·56; p=0·54). Mean POP-SS at 2 years were: standard 4·9 (SD 5·1) versus mesh 5·3 (5·1), mean difference 0·32, 95% CI -0·39 to 1·03; p=0·37; standard 4·9 (SD 5·1) versus graft 5·5 (5·7); mean difference 0·32, -0·48 to 1·12; p=0·43. Prolapse-related quality-of-life scores at 2 years were: standard 1·9 (SD 2·5) versus mesh 2·2 (2·6), mean difference 0·15, 95% CI -0·23 to 0·54; p=0·44; standard 2·0 (2·5) versus graft 2·2 (2·8); mean difference 0·10, -0·33 to 0·52; p=0·66. Serious adverse events such as infection, urinary retention, or dyspareunia or other pain, excluding mesh complications, occurred with similar frequency in the groups over 1 year (mesh trial: 31/430 [7%] with standard repair vs 34/435 [8%] with mesh, risk ratio [RR] 1·08, 95% CI 0·68 to 1·72; p=0·73; graft trial: 23/367 [6%] with standard repair vs 36/368 [10%] with graft, RR 1·57, 0·95 to 2·59; p=0·08). The cumulative number of women with a mesh complication over 2 years in women actually exposed to synthetic mesh was 51 (12%) of 434. Augmentation of a vaginal repair with mesh or graft material did not improve women's outcomes in terms of effectiveness, quality of life, adverse effects, or any other outcome in the short term, but more than one in ten women had a mesh complication. Therefore, follow-up is vital to identify any longer-term potential benefits and serious adverse effects of mesh or graft reinforcement in vaginal prolapse surgery. UK National Institute of Health Research. Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license. Published by Elsevier Ltd.. All rights reserved.

Altering surface characteristics of polypropylene mesh via sodium hydroxide treatment.

PubMed

Regis, Shawn; Jassal, Manisha; Mukherjee, Nilay; Bayon, Yves; Scarborough, Nelson; Bhowmick, Sankha

2012-05-01

Incisional hernias represent a serious and common complication following laparotomy. The use of synthetic (e.g. polypropylene) meshes to aid repair of these hernias has considerably reduced recurrence rates. While polypropylene is biocompatible and has a long successful clinical history in treating hernias and preventing reherniation, this material may suffer some limitations, particularly in challenging patients at risk of wound failure due to, for example, an exaggerated inflammation reaction, delayed wound healing, and infection. Surface modification of the polypropylene mesh without sacrificing its mechanical properties, critical for hernia repair, represents one way to begin to address these clinical complications. Our hypothesis is treatment of a proprietary polypropylene mesh with sodium hydroxide (NaOH) will increase in vitro NIH/3T3 cell attachment, predictive of earlier and improved cell colonization and tissue integration of polypropylene materials. Our goal is to achieve this altered surface functionality via enhanced removal of chemicals/oils used during material synthesis without compromising the mechanical properties of the mesh. We found that NaOH treatment does not appear to compromise the mechanical strength of the material, despite roughly a 10% decrease in fiber diameter. The treatment increases in vitro NIH/3T3 cell attachment within the first 72 h and this effect is sustained up to 7 days in vitro. This research demonstrates that sodium hydroxide treatment is an efficient way to modify the surface of polypropylene hernia meshes without losing the mechanical integrity of the material. This simple procedure could also allow the attachment of a variety of biomolecules to the polypropylene mesh that may aid in reducing the complications associated with polypropylene meshes today. Copyright © 2012 Wiley Periodicals, Inc.

Validation of a cage implant system for assessing in vivo performance of long-acting release microspheres.

PubMed

Doty, Amy C; Hirota, Keiji; Olsen, Karl F; Sakamoto, Naoya; Ackermann, Rose; Feng, Meihua R; Wang, Yan; Choi, Stephanie; Qu, Wen; Schwendeman, Anna; Schwendeman, Steven P

2016-12-01

Here we describe development of a silicone rubber/stainless steel mesh cage implant system, much like that used to assess biocompatibility of biomaterials [1], for easy removal of injectable polymer microspheres in vivo. The sterile cage has a type 316 stainless steel mesh size (38 μm) large enough for cell penetration and free fluid flow in vivo but small enough for microsphere retention, and a silicone rubber shell for injection of the microspheres. Two model drugs, the poorly soluble steroid, triamcinolone acetonide, and the highly water-soluble luteinizing hormone-releasing hormone (LHRH) peptide superagonist, leuprolide, were encapsulated in PLGA microspheres large enough (63-90 μm) to be restrained by the cage implant in vivo. The in vitro release from both formulations was followed by ultra-performance liquid chromatography (UPLC) with and without the cage in a standard release media, PBS pH 7.4 + 0.02% Tween 80 + 0.05% sodium azide, at 37 °C. Pharmacokinetics (PK) in rats was assessed after SC injection or SC in-cage implantation of microspheres with plasma analysis by LC-MS/MS or EIA. Tr-A and leuprolide in vitro release was largely unaffected after the initial burst irrespective of the cage or test tube incubation vessel and release was much slower than observed in vivo for both drugs. Moreover, Tr-A and leuprolide pharmacokinetics with and without the cage were highly similar during the 2-3 week release duration before a significant inflammatory response was caused by the cage implant. Hence, the PK-validated cage implant provides a simple means to recover and evaluate the microsphere drug carriers in vivo during a time window of at least a few weeks in order to characterize the polymer microsphere release and erosion behavior in vivo. This approach may facilitate development of mechanism-based in vitro/in vivo correlations and enable development of more accurate and useful in vitro release tests. Copyright © 2016 Elsevier Ltd. All rights reserved.

Marine Controlled-Source Electromagnetic 2D Inversion for synthetic models.

NASA Astrophysics Data System (ADS)

Liu, Y.; Li, Y.

2016-12-01

We present a 2D inverse algorithm for frequency domain marine controlled-source electromagnetic (CSEM) data, which is based on the regularized Gauss-Newton approach. As a forward solver, our parallel adaptive finite element forward modeling program is employed. It is a self-adaptive, goal-oriented grid refinement algorithm in which a finite element analysis is performed on a sequence of refined meshes. The mesh refinement process is guided by a dual error estimate weighting to bias refinement towards elements that affect the solution at the EM receiver locations. With the use of the direct solver (MUMPS), we can effectively compute the electromagnetic fields for multi-sources and parametric sensitivities. We also implement the parallel data domain decomposition approach of Key and Ovall (2011), with the goal of being able to compute accurate responses in parallel for complicated models and a full suite of data parameters typical of offshore CSEM surveys. All minimizations are carried out by using the Gauss-Newton algorithm and model perturbations at each iteration step are obtained by using the Inexact Conjugate Gradient iteration method. Synthetic test inversions are presented.

Radiographic and clinical outcomes of implants placed in ridge preserved sites: a 12-month post-loading follow-up.

PubMed

Patel, K; Mardas, N; Donos, N

2013-06-01

The aim of this clinical study was to evaluate the interproximal radiographic bone levels and the survival/success rate of dental implants placed in alveolar ridges previously preserved with a synthetic bone substitute or a bovine xenograft. Alveolar ridge preservation was performed in 27 patients who were randomly assigned in two groups. In the test group (n = 14), the extraction socket was treated with a synthetic bone graft Straumann Bone Ceramic; SBC and a collagen barrier, whereas in the control group (n = 13) a deproteinized bovine bone mineral (DBBM) and the same collagen barrier were used. After 8 months of healing, titanium dental implants with a hydrophilic surface were placed in the preserved ridges. During surgery, 9/13 implants in the SBC group and 8/12 implants in the DBBM group presented with either dehiscence or fenestration defects and required additional bone augmentation. The implants were loaded at 4 months following placement and were followed up for 1 year post-loading. Interproximal radiographic bone levels were evaluated in standardized periapical radiographs at loading and 1 year post-loading. Probing pocket depth, gingival recession and bleeding upon probing were recorded at implants and neighbouring teeth. The success rate of the implants was evaluated according to criteria set by Albrektsson et al. (1986). The survival rate of the implants in both groups was 100% at 1-year post-loading. No statistically significant differences in any of the clinical and radiographic measurements were detected between the two groups (P < 0.05). The success rate of the implants was 84.6% (11/13) in the SBC group and 83.3% (10/12) in the DBBM group. Equivalent success and survival rates (as well as similar radiographic changes) of dental implants placed in alveolar ridges previously preserved with SBC or DBBM should be anticipated. © 2012 John Wiley & Sons A/S.

Hip joint replacement using monofilament polypropylene surgical mesh: an animal model.

PubMed

Białecki, Jacek; Majchrzycki, Marian; Szymczak, Antoni; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof

2014-01-01

Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform.

Low modulus and bioactive Ti/α-TCP/Ti-mesh composite prepared by spark plasma sintering.

PubMed

Guo, Yu; Tan, Yanni; Liu, Yong; Liu, Shifeng; Zhou, Rui; Tang, Hanchun

2017-11-01

A titanium mesh scaffold composite filled with Ti/α-TCP particles was prepared by spark plasma sintering (SPS). The microstructures and interfacial reactions of the composites were investigated by scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The compressive strength and elastic modulus were also measured. In vitro bioactivity and biocompatibility was evaluated by using simulated body fluid and cells culture, respectively. After high temperature sintering, Ti oxides, Ti x P y and CaTiO 3 were formed. The formation of Ti oxides and Ti x P y were resulted from the diffusion of O and P elements from α-TCP to Ti. CaTiO 3 was the reaction product of Ti and α-TCP. The composite of 70Ti/α-TCP incorporated with Ti mesh showed a high compressive strength of 589MPa and a low compressive modulus of 30GPa. The bioactivity test showed the formation of a thick apatite layer on the composite and well-spread cells attachment. A good combination of mechanical properties and bioactivity indicated a high potential application of Ti/α-TCP/Ti-mesh composite for orthopedic implants. Copyright © 2017. Published by Elsevier B.V.

Parallel three-dimensional magnetotelluric inversion using adaptive finite-element method. Part I: theory and synthetic study

NASA Astrophysics Data System (ADS)

Grayver, Alexander V.

2015-07-01

This paper presents a distributed magnetotelluric inversion scheme based on adaptive finite-element method (FEM). The key novel aspect of the introduced algorithm is the use of automatic mesh refinement techniques for both forward and inverse modelling. These techniques alleviate tedious and subjective procedure of choosing a suitable model parametrization. To avoid overparametrization, meshes for forward and inverse problems were decoupled. For calculation of accurate electromagnetic (EM) responses, automatic mesh refinement algorithm based on a goal-oriented error estimator has been adopted. For further efficiency gain, EM fields for each frequency were calculated using independent meshes in order to account for substantially different spatial behaviour of the fields over a wide range of frequencies. An automatic approach for efficient initial mesh design in inverse problems based on linearized model resolution matrix was developed. To make this algorithm suitable for large-scale problems, it was proposed to use a low-rank approximation of the linearized model resolution matrix. In order to fill a gap between initial and true model complexities and resolve emerging 3-D structures better, an algorithm for adaptive inverse mesh refinement was derived. Within this algorithm, spatial variations of the imaged parameter are calculated and mesh is refined in the neighborhoods of points with the largest variations. A series of numerical tests were performed to demonstrate the utility of the presented algorithms. Adaptive mesh refinement based on the model resolution estimates provides an efficient tool to derive initial meshes which account for arbitrary survey layouts, data types, frequency content and measurement uncertainties. Furthermore, the algorithm is capable to deliver meshes suitable to resolve features on multiple scales while keeping number of unknowns low. However, such meshes exhibit dependency on an initial model guess. Additionally, it is demonstrated that the adaptive mesh refinement can be particularly efficient in resolving complex shapes. The implemented inversion scheme was able to resolve a hemisphere object with sufficient resolution starting from a coarse discretization and refining mesh adaptively in a fully automatic process. The code is able to harness the computational power of modern distributed platforms and is shown to work with models consisting of millions of degrees of freedom. Significant computational savings were achieved by using locally refined decoupled meshes.

A comparative evaluation of mandibular finite element models with different lengths and elements for implant biomechanics.

PubMed

Teixeira, E R; Sato, Y; Akagawa, Y; Shindoi, N

1998-04-01

Further validity of finite element analysis (FEA) in implant biomechanics requires an increase of modelled range and mesh refinement, and a consequent increase in element number and calculation time. To develop a new method that allows a decrease of the modelled range and element number (along with less calculation time and less computer memory), 10 FEA models of the mandible with different mesio-distal lengths and elements were constructed based on three-dimensional graphic data of the bone structure around an osseointegrated implant. Analysis of stress distribution followed by 100 N loading with the fixation of the most external planes of the models indicated that a minimal bone length of 4.2 mm of the mesial and distal sides was acceptable for FEA representation. Moreover, unification of elements located far away from the implant surface did not affect stress distribution. These results suggest that it may be possible to develop a replica FEA implant model of the mandible with less range and fewer elements without altering stress distribution.

The Effect of Temporal Gap Identification on Speech Perception by Users of Cochlear Implants

ERIC Educational Resources Information Center

Sagi, Elad; Kaiser, Adam R.; Meyer, Ted A.; Svirsky, Mario A.

2009-01-01

Purpose: This study examined the ability of listeners using cochlear implants (CIs) and listeners with normal hearing (NH) to identify silent gaps of different duration and the relation of this ability to speech understanding in CI users. Method: Sixteen NH adults and 11 postlingually deafened adults with CIs identified synthetic vowel-like…

Ultrasound biomicroscopy (UBM) and scanning acoustic microscopy (SAM) for the assessment of hernia mesh integration: a comparison to standard histology in an experimental model.

PubMed

Petter-Puchner, A; Gruber-Blum, S; Walder, N; Fortelny, R H; Redl, H; Raum, K

2014-08-01

Mesh integration is a key parameter for reliable and safe hernia repair. So far, its assessment is based on histology obtained from rare second-look operations or experimental research. Therefore, non-invasive high-resolution imaging techniques would be of great value. Ultrasound biomicroscopy (UBM) and scanning acoustic microscopy (SAM) have shown potential in the imaging of hard and soft tissues. This experimental study compared the detection of mesh integration, foreign body reaction and scar formation in UBM/SAM with standard histology. Ten titanized polypropylene meshes were implanted in rats in a model of onlay repair. 17 days postoperative animals were killed and samples were paraffin embedded for histology (H&E, Cresyl violet) or processed for postmortem UBM/SAM. The observation period was uneventful and meshes appeared well integrated. Relocation of neighboring cross-sectional levels could easily be achieved with the 40-MHz UBM and granulation tissue could be distinguished from adjacent muscle tissue layers. The spatial resolution of approximately 8 μm of the 200-MHz UBM system images was comparable to standard histology (2.5-5× magnification) and allowed a clear identification of mesh fibers and different tissue types, e.g., scar, fat, granulation, and muscle tissues, as well as vessels, abscedations, and foreign body giant cell clusters. This pilot study demonstrates the potential of high-frequency ultrasound to assess hernia mesh integration non-invasively. Although the methods lack cell-specific information, tissue integration could reliably be assessed. The possibility of conducting UBM in vivo advocates this method as a guidance tool for the indication of second-look operations and subsequent elaborate histological analyses.

Clinical feasibility of a new through-the-scope fully covered esophageal self-expandable metallic stent: an in vivo animal study.

PubMed

Cheon, Young Koog; Lee, Tae Yoon; Sung, In Kyung; Shim, Chan Sup

2014-01-01

Most delivery devices used for esophageal stents for obstructing esophageal cancer have a diameter of 5-8 mm, a size that is too large to pass through the endoscopic working channel. The conventional esophageal stent requires multiple endoscopic procedures for implantation. The purpose of the present study was to evaluate the clinical feasibility of a newly developed fully covered, self-expanding, through-the-scope (TTS) esophageal stent in a porcine model. Eight mini pigs were used. Each animal underwent placement of a fully covered TTS stent (Hanarostent® Esophagus TTS) and the upper part of the stent was fixed by suturing with nylon. Fluoroscopy was carried out every week to assess migration of the stent. Follow-up endoscopy was done every month for 3 months to evaluate the status of the membrane, stent mesh, grade of tissue hyperplasia, and mucosal changes at both ends of the stent. All stents were successfully and easily deployed, and were placed without any distortion in the stent or without rupture of the membrane. In two cases, stent migration was observed after 8 weeks. No case of membrane disruption, stent mesh disruption or tissue hyperplasia at either end of the stent was found at the completion of the study. Our findings indicate that the new fully covered self-expanding TTS esophageal stent is easy and simple to implant, and no significant distortion of mesh or disruption of membrane was observed. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

Performance effects of irregular communications patterns on massively parallel multiprocessors

NASA Technical Reports Server (NTRS)

Saltz, Joel; Petiton, Serge; Berryman, Harry; Rifkin, Adam

1991-01-01

A detailed study of the performance effects of irregular communications patterns on the CM-2 was conducted. The communications capabilities of the CM-2 were characterized under a variety of controlled conditions. In the process of carrying out the performance evaluation, extensive use was made of a parameterized synthetic mesh. In addition, timings with unstructured meshes generated for aerodynamic codes and a set of sparse matrices with banded patterns on non-zeroes were performed. This benchmarking suite stresses the communications capabilities of the CM-2 in a range of different ways. Benchmark results demonstrate that it is possible to make effective use of much of the massive concurrency available in the communications network.

78 FR 48656 - Procurement List; Proposed Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-09

..., Synthetic Mesh, 24x36, Locking Drawstring NSN: 3510-00-NIB-0013--Heavy Duty, \\3/16\\'' Hole Size. NSN: 3510-00-NIB-0014--Medium Duty, \\1/16\\'' Hole Size. NPA: Bestwork Industries for the Blind, Inc., Runnemede... NSN: 7510-01-462-1383--View Framed, Navy Blue, \\1/2\\''. NSN: 7510-01-462-1384--View Framed, Black, \\1...

Hydrodynamic Drag Force Measurement Of A Functionalized Surface Exhibiting Superhydrophobic Properties

DTIC Science & Technology

2016-12-01

22. Completed Test Stand. ...............................................................................24 Figure 23. Steel Spring and Mesh...topography that is superhydrophobic. Furthering this research, Zuhlke et al. [27] using FLSP, created stainless steel and titanium samples with...synthetic stomach acid. Each sample created attained initial wetting angles greater than 160 degrees while the stainless steel samples had a better

Microbial colonization at the implant-abutment interface and its possible influence on periimplantitis: A systematic review and meta-analysis.

PubMed

Tallarico, Marco; Canullo, Luigi; Caneva, Martina; Özcan, Mutlu

2017-07-01

The aim of this systematic review and meta-analysis was to evaluate the microbial colonization at the implant-abutment interfaces (IAI) on bone-level implants and to identify possible association with peri-implant conditions. The focus question aimed to answer whether two-piece osseointegrated implants, in function for at least 1 year, in human, relate to higher bacterial count and the onset of periimplantitis, compared to healthy peri-implant conditions. Search strategy encompassed the on-line (MedLine, Google scholar, Cochrane library) literature from 1990 up to March 2015 published in English using combinations of MeSH (Medical Subject Headings) and search terms. Quality assessment of selected full-text articles was performed according to the ARRIVE and CONSORT statement guidelines. For data analysis, the total bacterial count of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, and Fusobacterium nucleatum was calculated and compared to IAI with or without peri-implant pathology. A total of 14 articles, reporting data from 1126 implants, fulfilled the inclusion criteria and subjected to quality assessment. The selected studies revealed contamination of the IAI, in patients who received two-piece implant systems. Meta-analysis indicated significant difference in total bacterial count between implants affected by periimplantitis versus healthy peri-implant tissues (0.387±0.055; 95% CI 0.279-0.496). Less bacterial counts were identified in the healthy IAI for all the investigated gram-negative bacteria except for T. forsythia. Significantly higher bacterial counts were found for periodontal pathogenic bacteria within the IAI of implants in patients with periimplantitis compared to those implants surrounded by healthy peri-implant tissues. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Increasing synthetic serum substitute (SSS) concentrations in P1 glucose/phosphate-free medium improves implantation rate: a comparative study.

PubMed

Ben-Yosef, D; Yovel, I; Schwartz, T; Azem, F; Lessing, J B; Amit, A

2001-11-01

To assess the comparative efficacy of IVF medium (MediCult, with 5.2 mM glucose) and a glucose/phosphate-free medium, P1 (Irvine Scientific), and to investigate the influence of increasing the serum supplementation (synthetic serum substitute; SSS; Irvine Scientific) to P1 on embryo development and implantation. Patients were randomly assigned to IVF medium (Group 1, cycles n = 172) or P1 supplemented with 10% SSS (Group 2, cycles n = 229) according to the medium scheduled for use on the day of oocyte retrieval. Another 555 IVF consequent cycles (Group 3) were performed using increased SSS concentrations (20%) in P1 medium. In this large series of IVF cycles, we herein demonstrate that significantly higher pregnancy and implantation rates were found when embryos were cultured in glucose/phosphate-free medium P1 supplemented with 20% SSS compared to supplementation with the lower SSS concentration and with IVF medium.

Mesh size selectivity of the gillnet in East China Sea

NASA Astrophysics Data System (ADS)

Li, L. Z.; Tang, J. H.; Xiong, Y.; Huang, H. L.; Wu, L.; Shi, J. J.; Gao, Y. S.; Wu, F. Q.

2017-07-01

A production test using several gillnets with various mesh sizes was carried out to discover the selectivity of gillnets in the East China Sea. The result showed that the composition of the catch species was synthetically affected by panel height and mesh size. The bycatch species of the 10-m nets were more than those of the 6-m nets. For target species, the effect of panel height on juvenile fish was ambiguous, but the number of juvenile fish declined quickly with the increase in mesh size. According to model deviance (D) and Akaike’s information criterion, the bi-normal model provided the best fit for small yellow croaker (Larimichthy polyactis), and the relative retention was 0.2 and 1, respectively. For Chelidonichthys spinosus, the log-normal was the best model; the right tilt of the selectivity curve was obvious and well coincided with the original data. The contact population of small yellow croaker showed a bi-normal distribution, and body lengths ranged from 95 to 215 mm. The contact population of C. spinosus showed a normal distribution, and the body lengths ranged from 95 to 205 mm. These results can provide references for coastal fishery management.

Influence of mesh structure on 2D full shallow water equations and SCS Curve Number simulation of rainfall/runoff events

NASA Astrophysics Data System (ADS)

Caviedes-Voullième, Daniel; García-Navarro, Pilar; Murillo, Javier

2012-07-01

SummaryHydrological simulation of rain-runoff processes is often performed with lumped models which rely on calibration to generate storm hydrographs and study catchment response to rain. In this paper, a distributed, physically-based numerical model is used for runoff simulation in a mountain catchment. This approach offers two advantages. The first is that by using shallow-water equations for runoff flow, there is less freedom to calibrate routing parameters (as compared to, for example, synthetic hydrograph methods). The second, is that spatial distributions of water depth and velocity can be obtained. Furthermore, interactions among the various hydrological processes can be modeled in a physically-based approach which may depend on transient and spatially distributed factors. On the other hand, the undertaken numerical approach relies on accurate terrain representation and mesh selection, which also affects significantly the computational cost of the simulations. Hence, we investigate the response of a gauged catchment with this distributed approach. The methodology consists of analyzing the effects that the mesh has on the simulations by using a range of meshes. Next, friction is applied to the model and the response to variations and interaction with the mesh is studied. Finally, a first approach with the well-known SCS Curve Number method is studied to evaluate its behavior when coupled with a shallow-water model for runoff flow. The results show that mesh selection is of great importance, since it may affect the results in a magnitude as large as physical factors, such as friction. Furthermore, results proved to be less sensitive to roughness spatial distribution than to mesh properties. Finally, the results indicate that SCS-CN may not be suitable for simulating hydrological processes together with a shallow-water model.

Bone Replacement Materials and Techniques Used for Achieving Vertical Alveolar Bone Augmentation

PubMed Central

Sheikh, Zeeshan; Sima, Corneliu; Glogauer, Michael

2015-01-01

Alveolar bone augmentation in vertical dimension remains the holy grail of periodontal tissue engineering. Successful dental implant placement for restoration of edentulous sites depends on the quality and quantity of alveolar bone available in all spatial dimensions. There are several surgical techniques used alone or in combination with natural or synthetic graft materials to achieve vertical alveolar bone augmentation. While continuously improving surgical techniques combined with the use of auto- or allografts provide the most predictable clinical outcomes, their success often depends on the status of recipient tissues. The morbidity associated with donor sites for auto-grafts makes these techniques less appealing to both patients and clinicians. New developments in material sciences offer a range of synthetic replacements for natural grafts to address the shortcoming of a second surgical site and relatively high resorption rates. This narrative review focuses on existing techniques, natural tissues and synthetic biomaterials commonly used to achieve vertical bone height gain in order to successfully restore edentulous ridges with implant-supported prostheses.

Outcomes of abdominal wall reconstruction with acellular dermal matrix are not affected by wound contamination.

PubMed

Garvey, Patrick B; Martinez, Roberto A; Baumann, Donald P; Liu, Jun; Butler, Charles E

2014-11-01

The optimal type of mesh for complex abdominal wall reconstruction has not been elucidated. We hypothesized that AWRs using acellular dermal matrix (ADM) experience low rates of surgical site occurrence (SSO) and surgical site infection, despite increasing degrees of wound contamination. We retrospectively reviewed prospectively collected data from consecutive abdominal wall reconstructions with ADM over a 9-year period. Outcomes of abdominal wall reconstructions were compared between patients with different CDC wound classifications. Univariate and multivariate logistic regression and Cox proportional hazard regression analyses identified potential associations and predictive/protective factors. The 359 patients had a mean follow-up of 28.3 ± 19.0 months. Reconstruction of clean wounds (n = 171) required fewer reoperations than that of combined contaminated (n = 188) wounds (2.3% vs 11.2%; p = 0.001) and trended toward experiencing fewer SSOs (19.9% vs 28.7%, p = 0.052). There were no significant differences between clean and combined contaminated cases in 30-day SSI (8.8% vs 8.0%), hernia recurrence (9.9% vs 10.1%), and mesh removal (1.2% vs 1.1%) rates. Independent predictors of SSO included body mass index ≥30 kg/m(2) (odds ratio [OR] 3.6; p < 0.001), 1 or more comorbidities (OR 2.5; p = 0.008), and defect width ≥15 cm (OR 1.8; p = 0.02). Complex abdominal wall reconstructions using ADM demonstrated similar rates of complications between the different CDC wound classifications. This is in contradistinction to published outcomes for abdominal wall reconstruction using synthetic mesh that show progressively higher complication rates with increasing degrees of contamination. These data support the use of ADM rather than synthetic mesh for complex abdominal wall reconstruction in the setting of wound contamination. Copyright © 2014 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions.

PubMed

Callahan, Alison B; Campbell, Ashley A; Petris, Carisa; Kazim, Michael

Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions. A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case. Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision. The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

Influence of Alveolar Bone Defects on the Stress Distribution in Quad Zygomatic Implant-Supported Maxillary Prosthesis.

PubMed

Duan, Yuanyuan; Chandran, Ravi; Cherry, Denise

The purpose of this study was to create three-dimensional composite models of quad zygomatic implant-supported maxillary prostheses with a variety of alveolar bone defects around implant sites, and to investigate the stress distribution in the surrounding bone using the finite element analysis (FEA) method. Three-dimensional models of titanium zygomatic implants, maxillary prostheses, and human skulls were created and assembled using Mimics based on microcomputed tomography and cone beam computed tomography images. A variety of additional bone defects were created at the locations of four zygomatic implants to simulate multiple clinical scenarios. The volume meshes were created and exported into FEA software. Material properties were assigned respectively for all the structures, and von Mises stress data were collected and plotted in the postprocessing module. The maximum stress in the surrounding bone was located in the crestal bone around zygomatic implants. The maximum stress in the prostheses was located at the angled area of the implant-abutment connection. The model with anterior defects had a higher peak stress value than the model with posterior defects. All the models with additional bone defects had higher maximum stress values than the control model without additional bone loss. Additional alveolar bone loss has a negative influence on the stress concentration in the surrounding bone of quad zygomatic implant-supported prostheses. More care should be taken if these additional bone defects are at the sites of anterior zygomatic implants.

A prospective, randomized, controlled study comparing Gynemesh, a synthetic mesh, and Pelvicol, a biologic graft, in the surgical treatment of recurrent cystocele.

PubMed

Natale, F; La Penna, C; Padoa, A; Agostini, M; De Simone, E; Cervigni, M

2009-01-01

We compared safety and efficacy of Gynemesh PS and Pelvicol for recurrent cystocele repair. One hundred ninety patients were randomly divided into Gynemesh PS and Pelvicol groups and underwent tension-free cystocele repair. The Chi-square test was used to compare categorical variables, the paired t test for continuous parametric variables, and the Mann-Whitney test for continuous nonparametric variables. Ninety-six Gynemesh PS patients and 94 Pelvicol patients were studied. Mesh erosions occurred in 6.3% of Gynemesh PS patients. No erosions were observed in Pelvicol patients (p = 0.02). Objective cure was 71.9% for Gynemesh PS and 56.4% for Pelvicol (p = 0.06). Subjective cure was the same in both groups except for better sexuality in the Pelvicol group. At 24 months follow-up, only Gynemesh PS patients had mesh erosions. Anatomical outcome was similar in the two groups. Pelvicol gave a better impact on voiding and sexuality.

Stabilization of the Chest Wall: Autologous and Alloplastic Reconstructions

PubMed Central

Mahabir, Raman Chaos; Butler, Charles E.

2011-01-01

The goals of chest wall stabilization include maintenance of a rigid airtight cavity, protection of the thoracic and abdominal contents, optimization of respiration, and, whenever possible, an aesthetic reconstruction. Evidence suggests that bony fixation results in reduced ventilator dependence, a shorter overall hospital stay, and improved upper extremity function. We prefer to accomplish this with autologous tissue alone (such as the pectoralis major, latissimus dorsi, or rectus abdominus muscle flaps) for small to moderate defects. En bloc resection of defects larger than 5 cm or containing four or more ribs will likely benefit from chest wall stabilization. For patients previously treated with radiation, even larger defects may be tolerated owing to fibrosis. For these larger defects, methyl methacrylate composite meshes are used and covered with vascularized tissue. Contaminated wounds are generally reconstructed with bioprosthetic mesh rather than synthetic mesh. Using these principles, the reconstructive plastic surgeon can devise a comprehensive and safe plan to repair tremendous defects of the chest wall. PMID:22294941

Successful repair of a ventricular assist system percutaneous lead.

PubMed

Pantalos, G M; Marks, J D; Richardson, E E; Nelson, K E; Long, J W

1999-01-01

A patient with an implanted, electrically powered, ventricular assist device (Thermo Cardiosystems VE HeartMate) experienced a partial break of the percutaneous lead 5 months after implantation. The break (limited to the Silicone rubber tube) occurred at the junction of the lead with the Y-connector to the controller and vent, leaving approximately 5 cm of exposed lead from the skin exit site to the connector. Electronic and pumping functions of the pump continued, but the opening in the lead (which went more that half way around the circumference) prevented the use of pneumatic actuation as a back-up mode for pump operation, and placed the pump at risk for contamination. Repair of the lead without surgical intervention was desirable, with ease of repair and minimal risk to the patient being the top priorities. The use of multiple layers of heat-shrink tubing or external metal stents was ruled out in favor of a three stage repair procedure. The first stage involved the removal of the Dacron velour in-growth material from the lead to expose the underlying Silicone rubber tube. While the opening in the tube was held shut, a coating of medical grade Silicone rubber adhesive was applied to the tube, then wrapped with a woven Dacron mesh, followed by two layers of plastic wrapping material to protect the adhesive. This initial layer was secured by an external stent of tubing with cable ties. After several days to allow for complete curing of the adhesive, the adhesive coating with mesh was repeated. The final step involved a double layer wrap of a 1 mm thick Silicone rubber sheeting with mesh incorporation and adhesive secured in place with cable ties. After completion of the repair and verification of the ability to operate the device with pneumatic actuation, the patient was discharged with no recurrence of the problem after 8 months of weekly follow-up. This experience demonstrates the need to clinically anticipate component repair or replacement without total device replacement in future implantable blood pump systems.

[Fine mesh metal endoprostheses for treatment of extensive cervical and intrathoracic tracheomalacia].

PubMed

Wilmes, E; Berger, H; Dienemann, H; Jolk, A

1994-01-01

The treatment of tracheal stenoses caused by tracheomalacia is mainly carried out by means of sleeve resection, tracheopexy with ring support or other tracheoplastic operative procedures. If patients cannot be treated by surgical operative strategies, conventional stents are usually used to dilate the trachea. The use of a self-expanding elastic metal prosthesis in 5 patients with tracheal airway obstruction caused by tracheomalacia proved to be a true alternative in the therapy of tracheobronchial stenoses. We report on the long term use of 5 patients with tracheal stenoses treated by implantation of elastic metal wallstents. The implantation of the stents resulted in immediate improvement in respiratory function in all 5 patients. None of the patients experienced complications secondary to the stent placement. The stents were well tolerated (long-time follow-up 26 months). The implantation of self-expanding metal stents type "wallstent" seems to offer alternative possibilities for the treatment of tracheomalacia.

3-D inversion of airborne electromagnetic data parallelized and accelerated by local mesh and adaptive soundings

NASA Astrophysics Data System (ADS)

Yang, Dikun; Oldenburg, Douglas W.; Haber, Eldad

2014-03-01

Airborne electromagnetic (AEM) methods are highly efficient tools for assessing the Earth's conductivity structures in a large area at low cost. However, the configuration of AEM measurements, which typically have widely distributed transmitter-receiver pairs, makes the rigorous modelling and interpretation extremely time-consuming in 3-D. Excessive overcomputing can occur when working on a large mesh covering the entire survey area and inverting all soundings in the data set. We propose two improvements. The first is to use a locally optimized mesh for each AEM sounding for the forward modelling and calculation of sensitivity. This dedicated local mesh is small with fine cells near the sounding location and coarse cells far away in accordance with EM diffusion and the geometric decay of the signals. Once the forward problem is solved on the local meshes, the sensitivity for the inversion on the global mesh is available through quick interpolation. Using local meshes for AEM forward modelling avoids unnecessary computing on fine cells on a global mesh that are far away from the sounding location. Since local meshes are highly independent, the forward modelling can be efficiently parallelized over an array of processors. The second improvement is random and dynamic down-sampling of the soundings. Each inversion iteration only uses a random subset of the soundings, and the subset is reselected for every iteration. The number of soundings in the random subset, determined by an adaptive algorithm, is tied to the degree of model regularization. This minimizes the overcomputing caused by working with redundant soundings. Our methods are compared against conventional methods and tested with a synthetic example. We also invert a field data set that was previously considered to be too large to be practically inverted in 3-D. These examples show that our methodology can dramatically reduce the processing time of 3-D inversion to a practical level without losing resolution. Any existing modelling technique can be included into our framework of mesh decoupling and adaptive sampling to accelerate large-scale 3-D EM inversions.

Histologic and biomechanical evaluation of a novel macroporous polytetrafluoroethylene knit mesh compared to lightweight and heavyweight polypropylene mesh in a porcine model of ventral incisional hernia repair

PubMed Central

Melman, L.; Jenkins, E. D.; Hamilton, N. A.; Bender, L. C.; Brodt, M. D.; Deeken, C. R.; Greco, S. C.; Frisella, M. M.

2013-01-01

Purpose To evaluate the biocompatibility of heavyweight polypropylene (HWPP), lightweight polypropylene (LWPP), and monofilament knit polytetrafluoroethylene (mkPTFE) mesh by comparing biomechanics and histologic response at 1, 3, and 5 months in a porcine model of incisional hernia repair. Methods Bilateral full-thickness abdominal wall defects measuring 4 cm in length were created in 27 Yucatan minipigs. Twenty-one days after hernia creation, animals underwent bilateral preperitoneal ventral hernia repair with 8 × 10 cm pieces of mesh. Repairs were randomized to Bard®Mesh (HWPP, Bard/Davol, http://www.davol.com), ULTRAPRO® (LWPP, Ethicon, http://www.ethicon.com), and GORE®INFINIT Mesh (mkPTFE, Gore & Associates, http://www.gore.com). Nine animals were sacrificed at each timepoint (1, 3, and 5 months). At harvest, a 3 × 4 cm sample of mesh and incorporated tissue was taken from the center of the implant site and subjected to uniaxial tensile testing at a rate of 0.42 mm/s. The maximum force (N) and tensile strength (N/cm) were measured with a tensiometer, and stiffness (N/mm) was calculated from the slope of the force-versus-displacement curve. Adjacent sections of tissue were stained with hematoxylin and eosin (H&E) and analyzed for inflammation, fibrosis, and tissue ingrowth. Data are reported as mean ± SEM. Statistical significance (P < 0.05) was determined using a two-way ANOVA and Bonferroni post-test. Results No significant difference in maximum force was detected between meshes at any of the time points (P > 0.05 for all comparisons). However, for each mesh type, the maximum strength at 5 months was significantly lower than that at 1 month (P < 0.05). No significant difference in stiffness was detected between the mesh types or between timepoints (P > 0.05 for all comparisons). No significant differences with regard to inflammation, fibrosis, or tissue ingrowth were detected between mesh types at any time point (P > 0.09 for all comparisons). However, over time, inflammation decreased significantly for all mesh types (P < 0.001) and tissue ingrowth reached a slight peak between 1 and 3 months (P = 0.001) but did not significantly change thereafter (P > 0.09). Conclusions The maximum tensile strength of mesh in the abdominal wall decreased over time for HWPP, LWPP, and mkPTFE mesh materials alike. This trend may actually reflect inability to adequately grip specimens at later time points rather than any mesh-specific trend. Histologically, inflammation decreased with time (P = 0.000), and tissue ingrowth increased (P = 0.019) for all meshes. No specific trends were observed between the polypropylene meshes and the monofilament knit PTFE, suggesting that this novel construction may be a suitable alternative to existing polypropylene meshes. PMID:21279663

Histologic and biomechanical evaluation of a novel macroporous polytetrafluoroethylene knit mesh compared to lightweight and heavyweight polypropylene mesh in a porcine model of ventral incisional hernia repair.

PubMed

Melman, L; Jenkins, E D; Hamilton, N A; Bender, L C; Brodt, M D; Deeken, C R; Greco, S C; Frisella, M M; Matthews, B D

2011-08-01

To evaluate the biocompatibility of heavyweight polypropylene (HWPP), lightweight polypropylene (LWPP), and monofilament knit polytetrafluoroethylene (mkPTFE) mesh by comparing biomechanics and histologic response at 1, 3, and 5 months in a porcine model of incisional hernia repair. Bilateral full-thickness abdominal wall defects measuring 4 cm in length were created in 27 Yucatan minipigs. Twenty-one days after hernia creation, animals underwent bilateral preperitoneal ventral hernia repair with 8 × 10 cm pieces of mesh. Repairs were randomized to Bard(®)Mesh (HWPP, Bard/Davol, http://www.davol.com), ULTRAPRO(®) (LWPP, Ethicon, http://www.ethicon.com), and GORE(®)INFINIT Mesh (mkPTFE, Gore & Associates, http://www.gore.com). Nine animals were sacrificed at each timepoint (1, 3, and 5 months). At harvest, a 3 × 4 cm sample of mesh and incorporated tissue was taken from the center of the implant site and subjected to uniaxial tensile testing at a rate of 0.42 mm/s. The maximum force (N) and tensile strength (N/cm) were measured with a tensiometer, and stiffness (N/mm) was calculated from the slope of the force-versus-displacement curve. Adjacent sections of tissue were stained with hematoxylin and eosin (H&E) and analyzed for inflammation, fibrosis, and tissue ingrowth. Data are reported as mean ± SEM. Statistical significance (P < 0.05) was determined using a two-way ANOVA and Bonferroni post-test. No significant difference in maximum force was detected between meshes at any of the time points (P > 0.05 for all comparisons). However, for each mesh type, the maximum strength at 5 months was significantly lower than that at 1 month (P < 0.05). No significant difference in stiffness was detected between the mesh types or between timepoints (P > 0.05 for all comparisons). No significant differences with regard to inflammation, fibrosis, or tissue ingrowth were detected between mesh types at any time point (P > 0.09 for all comparisons). However, over time, inflammation decreased significantly for all mesh types (P < 0.001) and tissue ingrowth reached a slight peak between 1 and 3 months (P = 0.001) but did not significantly change thereafter (P > 0.09). The maximum tensile strength of mesh in the abdominal wall decreased over time for HWPP, LWPP, and mkPTFE mesh materials alike. This trend may actually reflect inability to adequately grip specimens at later time points rather than any mesh-specific trend. Histologically, inflammation decreased with time (P = 0.000), and tissue ingrowth increased (P = 0.019) for all meshes. No specific trends were observed between the polypropylene meshes and the monofilament knit PTFE, suggesting that this novel construction may be a suitable alternative to existing polypropylene meshes.

A preliminary report on the usage of an intracorporal antibiotic cast with synthetic high purity CaSO4 for the treatment of infected penile implant.

PubMed

Swords, Kelly; Martinez, Daniel R; Lockhart, Jorge L; Carrion, Rafael

2013-04-01

Currently, the surgical treatment of infected penile prostheses is complete removal and either immediate salvage procedure, which carries a significant infection risk, or delayed implantation. With delayed implantation the risk of infection is lower, but the patient loses penile length and width due to corporal fibrosis. We present our experience with the use of a novel temporary synthetic high purity calcium sulfate (SHPCaSO4) component that acts as a "spacer" at the time of removal of an infected prosthesis while providing constant delivery of local antibiotic elution to the infected area. Demonstrate that the use of a novel material, SHPCaSO4, can be an innovative way to bridge the gap between removal of an infected penile implant and delayed reimplantation. Two patients (Patient A and B) presented with pain and erythema and were found to have infected malleable penile prosthesis. Both underwent removal of all infected components, and sent for tissue culture. The SHPCaSO4 was mixed with vancomycin and tobramycin, allowed to set up for 5 minutes, and then injected into the corporal space followed by closure with 2-0 Vicryl sutures. The injected SHPCaSO4 was palpable in the penile shaft both proximally and distally, as an "intracorporal casts." Patients denied pain postoperatively. Delayed implantation occurred at 6 weeks for patient A. This went uneventful and a new three-piece inflatable implant was inserted. Patient B underwent salvage placement of right malleable implant at 15 weeks, and here significant corporal fibrosis was encountered. Patients have had no infection since their delayed implantation (mean follow-up 4 months). Data in reference to SHPCaSO4 shows that this product dissolves in approximately 4-6 weeks. This may account for the difference in the ease of delayed implantation between the two patients. Further investigation is warranted. © 2013 International Society for Sexual Medicine.

An allogenic cell-based implant for meniscal lesions.

PubMed

Weinand, Christian; Peretti, Giuseppe M; Adams, Samuel B; Bonassar, Lawrence J; Randolph, Mark A; Gill, Thomas J

2006-11-01

Meniscal tears in the avascular zones do not heal. Although tissue-engineering approaches using cells seeded onto scaffolds could expand the indication for meniscal repair, harvesting autologous cells could cause additional trauma to the patient. Allogenic cells, however, could provide an unlimited amount of cells. Allogenic cells from 2 anatomical sources can repair lesions in the avascular region of the meniscus. Controlled laboratory study. Both autologous and allogenic chondrocytes were seeded onto a Vicryl mesh scaffold and sutured into a bucket-handle lesion created in the medial menisci of 17 swine. Controls consisted of 3 swine knees treated with unseeded implants and controls from a previous experiment in which 4 swine were treated with suture only and 4 with no treatment. Menisci were harvested after 12 weeks and evaluated histologically for new tissue and percentage of interface healing surface; they were also evaluated statistically. The lesions were closed in 15 of 17 menisci. None of the control samples demonstrated healing. Histologic analysis of sequential cuts through the lesion showed formation of new scar-like tissue in all experimental samples. One of 8 menisci was completely healed in the allogenic group and 2 of 9 in the autologous group; the remaining samples were partially healed in both groups. No statistically significant differences in the percentage of healing were observed between the autologous and allogenic cell-based implants. Use of autologous and allogenic chondrocytes delivered via a biodegradable mesh enhanced healing of avascular meniscal lesions. This study demonstrates the potential of a tissue-engineered cellular repair of the meniscus using autologous and allogenic chondrocytes.

Bone Ceramic® at Implants Installed Immediately into Extraction Sockets in the Molar Region: An Experimental Study in Dogs.

PubMed

Pereira, Flávia Priscila; Hochuli-Vieira, Eduardo; Maté Sánchez de Val, José E; De Santis, Enzo; Salata, Luiz Antonio; Botticelli, Daniele

2016-04-01

The aim of this paper was to study the healing of 1-1.4 mm wide buccal defects at implants placed immediately into extraction sockets (IPIES) filled with a mixture of synthetic hydroxyapatite (HA) 60% and beta-tricalciumphosphate (TCP) 40% or left with the clot alone and both covered with collagen membranes. Eight Labrador dogs were used and implants were placed immediately into the extraction sockets of the first molar bilaterally. A mixture of synthetic HA 60% and beta-TCP 40% at the test or the clot alone at the control sites were used to fill the defects. All surgical sites were subsequently covered by a resorbable collagen membrane and a non-submerged healing was allowed. After 4 months, the animals were euthanized, biopsies harvested and processed for histomorphometric analysis. At the time of installation, residual buccal defects occurred that were 1.1 mm and 1.4 mm wide and 3 mm and 4 mm deep at the control and test sites, respectively. After 4 months of healing, the top of the bony crest and the coronal level of osseointegration were located respectively at 0.1 ± 1.8 mm and 1.5 ± 1.8 mm at the test, and 0.6 ± 1.6 mm and 1.2 ± 0.7 mm at the control sites apically to the implant shoulder. Bone-to-implant contact at the buccal aspect was 34.9 ± 25.9% and 36.4 ± 17.3% at the test and control sites, respectively. No statistically significant differences were found between test and control sites for any of the variables analyzed at the buccal aspects. The use of a mixture of synthetic HA 60% and beta-TCP 40% to fill residual buccal defects 1-1.4 mm wide at IPIES did not improve significantly the results of healing. © 2015 Wiley Periodicals, Inc.

Hip Joint Replacement Using Monofilament Polypropylene Surgical Mesh: An Animal Model

PubMed Central

Białecki, Jacek; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof

2014-01-01

Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform. PMID:24987672

Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells.

PubMed

Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

2017-01-01

Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide- co -glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types.

Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells

PubMed Central

Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

2017-01-01

Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide-co-glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types. PMID:28223803

Silk fibroin hydrogel as physical barrier for prevention of post hernia adhesion.

PubMed

Konar, S; Guha, R; Kundu, B; Nandi, S; Ghosh, T K; Kundu, S C; Konar, A; Hazra, S

2017-02-01

Adhesion formation remains a major complication following hernia repair surgery. Physical barriers though effective for adhesion prevention in clinical settings are associated with major disadvantages, therefore, needs further investigation. This study evaluates silk fibroin hydrogel as a physical barrier on polypropylene mesh for the prevention of adhesion following ventral hernia repair. Peritoneal explants were cultured on silk fibroin scaffold to evaluate its support for mesothelial cell growth. Full thickness uniform sized defects were created on the ventral abdominal wall of rabbits, and the defects were covered either with silk hydrogel coated polypropylene mesh or with plain polypropylene mesh as a control. The animals were killed after 1 month, and the adhesion formation was graded; healing response of peritoneum was evaluated by immunohistochemistry with calretinin, collagen staining of peritoneal sections, and expression of PCNA, collagen-I, TNFα, IL6 by real time PCR; and its adverse effect if any was determined. Silk fibroin scaffold showed excellent support for peritoneal cell growth in vitro and the cells expressed calretinin. A remarkable prevention of adhesion formation was observed in the animals implanted with silk hydrogel coated mesh compared to the control group; in these animals peritoneal healing was complete and predominantly by mesothelial cells with minimum fibrotic changes. Expression of inflammatory cytokines decreased compared to control animals, histology of abdominal organs, haematological and blood biochemical parameters remained normal. Therefore, silk hydrogel coating of polypropylene mesh can improve peritoneal healing, minimize adhesion formation, is safe and can augment the outcome of hernia surgery.

The influence of cell morphology on the compressive fatigue behavior of Ti-6Al-4V meshes fabricated by electron beam melting.

PubMed

Zhao, S; Li, S J; Hou, W T; Hao, Y L; Yang, R; Misra, R D K

2016-06-01

Additive manufacturing technique is a promising approach for fabricating cellular bone substitutes such as trabecular and cortical bones because of the ability to adjust process parameters to fabricate different shapes and inner structures. Considering the long term safe application in human body, the metallic cellular implants are expected to exhibit superior fatigue property. The objective of the study was to study the influence of cell shape on the compressive fatigue behavior of Ti-6Al-4V mesh arrays fabricated by electron beam melting. The results indicated that the underlying fatigue mechanism for the three kinds of meshes (cubic, G7 and rhombic dodecahedron) is the interaction of cyclic ratcheting and fatigue crack growth on the struts, which is closely related to cumulative effect of buckling and bending deformation of the strut. By increasing the buckling deformation on the struts through cell shape design, the cyclic ratcheting rate of the meshes during cyclic deformation was decreased and accordingly, the compressive fatigue strength was increased. With increasing bending deformation of struts, fatigue crack growth in struts contributed more to the fatigue damage of meshes. Rough surface and pores contained in the struts significantly deteriorated the compressive fatigue strength of the struts. By optimizing the buckling and bending deformation through cell shape design, Ti-6Al-4V alloy cellular solids with high fatigue strength and low modulus can be fabricated by the EBM technique. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of angiogenesis in implant dentistry part I: Review of titanium alloys, surface characteristics and treatments.

PubMed

Saghiri, M-A; Asatourian, A; Garcia-Godoy, F; Sheibani, N

2016-07-01

Angiogenesis plays an important role in osseointegration process by contributing to inflammatory and regenerative phases of surrounding alveolar bone. The present review evaluated the effect of titanium alloys and their surface characteristics including: surface topography (macro, micro, and nano), surface wettability/energy, surface hydrophilicity or hydrophobicity, surface charge, and surface treatments of dental implants on angiogenesis events, which occur during osseointegration period. An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in the PubMed and MeSH headings regarding the role of angiogenesis in implant dentistry from January 2000-April 2014. Of the 2,691 articles identified in our initial search results, only 30 met the inclusion criteria set for this review. The hydrophilicity and topography of dental implants are the most important and effective surface characteristics in angiogenesis and osteogenesis processes. The surface treatments or modifications of dental implants are mainly directed through the enhancement of biological activity and functionalization in order to promote osteogenesis and angiogenesis, and accelerate the osseointegration procedure. Angiogenesis is of great importance in implant dentistry in a manner that most of the surface characteristics and treatments of dental implants are directed toward creating a more pro-angiogenic surface on dental implants. A number of studies discussed the effect of titanium alloys, dental implant surface characteristic and treatments on agiogenesis process. However, clinical trials and in-vivo studies delineating the mechanisms of dental implants, and their surface characteristics or treatments, action in angiogenesis processes are lagging.

Reward-based hypertension control by a synthetic brain-dopamine interface.

PubMed

Rössger, Katrin; Charpin-El Hamri, Ghislaine; Fussenegger, Martin

2013-11-05

Synthetic biology has significantly advanced the design of synthetic trigger-controlled devices that can reprogram mammalian cells to interface with complex metabolic activities. In the brain, the neurotransmitter dopamine coordinates communication with target neurons via a set of dopamine receptors that control behavior associated with reward-driven learning. This dopamine transmission has recently been suggested to increase central sympathetic outflow, resulting in plasma dopamine levels that correlate with corresponding brain activities. By functionally rewiring the human dopamine receptor D1 (DRD1) via the second messenger cyclic adenosine monophosphate (cAMP) to synthetic promoters containing cAMP response element-binding protein 1(CREB1)-specific cAMP-responsive operator modules, we have designed a synthetic dopamine-sensitive transcription controller that reversibly fine-tunes specific target gene expression at physiologically relevant brain-derived plasma dopamine levels. Following implantation of circuit-transgenic human cell lines insulated by semipermeable immunoprotective microcontainers into mice, the designer device interfaced with dopamine-specific brain activities and produced a systemic expression response when the animal's reward system was stimulated by food, sexual arousal, or addictive drugs. Reward-triggered brain activities were able to remotely program peripheral therapeutic implants to produce sufficient amounts of the atrial natriuretic peptide, which reduced the blood pressure of hypertensive mice to the normal physiologic range. Seamless control of therapeutic transgenes by subconscious behavior may provide opportunities for treatment strategies of the future.

Stretchable surfaces with programmable 3D texture morphing for synthetic camouflaging skins

NASA Astrophysics Data System (ADS)

Pikul, J. H.; Li, S.; Bai, H.; Hanlon, R. T.; Cohen, I.; Shepherd, R. F.

2017-10-01

Technologies that use stretchable materials are increasingly important, yet we are unable to control how they stretch with much more sophistication than inflating balloons. Nature, however, demonstrates remarkable control of stretchable surfaces; for example, cephalopods can project hierarchical structures from their skin in milliseconds for a wide range of textural camouflage. Inspired by cephalopod muscular morphology, we developed synthetic tissue groupings that allowed programmable transformation of two-dimensional (2D) stretchable surfaces into target 3D shapes. The synthetic tissue groupings consisted of elastomeric membranes embedded with inextensible textile mesh that inflated to within 10% of their target shapes by using a simple fabrication method and modeling approach. These stretchable surfaces transform from flat sheets to 3D textures that imitate natural stone and plant shapes and camouflage into their background environments.

Materials and technologies for soft implantable neuroprostheses

NASA Astrophysics Data System (ADS)

Lacour, Stéphanie P.; Courtine, Grégoire; Guck, Jochen

2016-10-01

Implantable neuroprostheses are engineered systems designed to restore or substitute function for individuals with neurological deficits or disabilities. These systems involve at least one uni- or bidirectional interface between a living neural tissue and a synthetic structure, through which information in the form of electrons, ions or photons flows. Despite a few notable exceptions, the clinical dissemination of implantable neuroprostheses remains limited, because many implants display inconsistent long-term stability and performance, and are ultimately rejected by the body. Intensive research is currently being conducted to untangle the complex interplay of failure mechanisms. In this Review, we emphasize the importance of minimizing the physical and mechanical mismatch between neural tissues and implantable interfaces. We explore possible materials solutions to design and manufacture neurointegrated prostheses, and outline their immense therapeutic potential.

A new design concept for knitted external vein-graft support mesh.

PubMed

Singh, Charanpreet; Wang, Xungai

2015-08-01

Autologous vein-graft failure significantly limits the long-term efficacy of coronary artery bypass procedures. The major cause behind this complication is biomechanical mismatch between the vein and coronary artery. The implanted vein experiences a sudden increase (10-12 fold) in luminal pressures. The resulting vein over-distension or 'ballooning' initiates wall thickening phenomenon and ultimate occlusion. Therefore, a primary goal in improving the longevity of a coronary bypass procedure is to inhibit vein over-distension using mechanical constriction. The idea of using an external vein-graft support mesh has demonstrated sustained benefits and wide acceptance in experimental studies. Nitinol based knitted structures have offered more promising mechanical features than other mesh designs owing to their unique loosely looped construction. However, the conventional plain knit construction still exhibits limitations (radial compliance, deployment ease, flexibility, and bending stresses) which limit this design from proving its real clinical advantage. The new knitted mesh design presented in this study is based on the concept of composite knitting utilising high modulus (nitinol and polyester) and low modulus (polyurethane) material components. The experimental comparison of the new design with a plain knit design demonstrated significant improvement in biomechanical (compliance, flexibility, extensibility, viscoelasticity) and procedural (deployment limit) parameters. The results are indicative of the promising role of new mesh in restoring the lost compliance and pulsatility of vein-graft at high arterial pressures. This way it can assist in controlled vein-graft remodelling and stepwise restoration of vein mechanical homoeostasis. Also, improvement in deployment limit parameter offers more flexibility for a surgeon to use a wide range of vein diameters, which may otherwise be rendered unusable for a plain knit mesh. Copyright © 2015 Elsevier Ltd. All rights reserved.

[New options in reconstructive pelvic floor surgery and surgery in urogynecology].

PubMed

Martan, A

2006-12-01

The aim of this paper is to provide a brief update review of reconstructive pelvic floor surgery and surgery in urogynecology, including the application of surgical implants. Review article. Gynecological and Obstetric Clinic, 1 LF UK and VFN, Prague. Summarization, compilation and classification of recent findings, opinions and recommendations on new options in surgical procedures of reconstructive pelvic floor surgery and surgery in gynecology, with emphasis on the use of implants and their introduction into common clinical practice. From the beginning of the 1990s, the view of pelvic floor defects and urinary incontinence in women started to change significantly. The validity of De Lancey's classification of vaginal fixation into 3 basic levels was confirmed, with resulting modifications in surgical procedures. The etiology of pelvic floor defects comprises not only labor trauma or incorrectly performed previous operations (e.g. hysterectomy), but also hereditary influences and changes in the metabolism of the connective tissue. When comparing patients with or without descensus, there is a significant difference in the composition of collagen connective tissue; these findings, and the frequency of recurrence in up to 40% of patients within 3 years after the operations, resulted in the introduction of allogenous implants--meshes in the surgical treatment. These have been used for a long time in surgical treatment of abdominal wall defects, and for the above reasons the polypropylene meshes were introduced in pelvic floor defects surgery, while their safety has been proved in accordance with the principles of Evidence Based Medicine. In gynecology, these materials are already used in the laparoscopic approach to treat female stress incontinence. Pelvic floor defects occur either isolated, or combined (a defect of anterior, posterior or medial segment, or combination of all), while the patients may at the same time suffer from a stress type of urinary incontinence (SI). In surgical treatment of this type of urinary incontinence (TVT, TVT-O, TVT-S) allogenous implants--tapes--are frequently used. The results of studies suggest that one factor affecting the success of the operation using allogenous implants is the surgeon's erudition and experience in pelvic and vaginal surgery, while the long-term effect of the operation also depends on the surgical procedure involved, i.e. on the correct selection of operation methods and decision whether to use an implant or not. The effect of various operations using implants may differ as well, especially there is a difference between operations where the implant is placed freely under the bladder, and those where it is stabilized by fixing the arms of the implant under the lower arms of symphysis. Another factor to consider is the material of the implant used. Material currently recommended according to Evidence Based Medicine is: a lightweight, flexible polypropylene; and according to Amid's classification: type 1, i.e. macro-porous, monofilament material. The advantage of surgical treatment of pelvic floor defect using implants consists in a low percentage of recurrence of the descensus; there is, however, a certain risk of rejection (around 5%) and shrinking of tissues provoked by the implant.

Synthetic cornea: biocompatibility and optics

NASA Astrophysics Data System (ADS)

Parel, Jean-Marie A.; Kaminski, Stefan; Fernandez, Viviana; Alfonso, E.; Lamar, Peggy; Lacombe, Emmanuel; Duchesne, Bernard; Dubovy, Sander; Manns, Fabrice; Rol, Pascal O.

2002-06-01

Purpose. Experimentally find a method to provide a safe surgical technique and an inexpensive and long lasting mesoplant for the restoration of vision in patients with bilateral corneal blindness due to ocular surface and stromal diseases. Methods. Identify the least invasive and the safest surgical technique for synthetic cornea implantation. Identify the most compatible biomaterials and the optimal shape a synthetic cornea must have to last a long time when implanted in vivo. Results. Penetrating procedures were deemed too invasive, time consuming, difficult and prone to long term complications. Therefore a non-penetrating delamination technique with central trephination was developed to preserve the integrity of Descemet's membrane and the anterior segment. Even though this approach limits the number of indications, it is acceptable since the majority of patients only have opacities in the stroma. The prosthesis was designed to fit in the removed tissue plane with its skirt fitted under the delaminated stroma. To improve retention, the trephination wall was made conical with the smallest opening on the anterior surface and a hat-shaped mesoplant was made to fit. The skirt was perforated in its perimeter to allow passage of nutrients and tissues ingrowths. To simplify the fabrication procedure, the haptic and optic were made of the same polymer. The intrastromal biocompatibility of several hydrogels was found superior to current clinically used PMMA and PTFE materials. Monobloc mesoplants made of 4 different materials were implanted in rabbits and followed weekly until extrusion occurred. Some remained optically clear allowing for fundus photography. Conclusions. Hydrogel synthetic corneas can be made to survive for periods longer than 1 year. ArF excimer laser photoablation studies are needed to determine the refractive correction potential of these mesoplants. A pilot FDA clinical trial is needed to assess the mesoplant efficacy and very long-term stability.

Development of HEATHER for cochlear implant stimulation using a new modeling workflow.

PubMed

Tran, Phillip; Sue, Andrian; Wong, Paul; Li, Qing; Carter, Paul

2015-02-01

The current conduction pathways resulting from monopolar stimulation of the cochlear implant were studied by developing a human electroanatomical total head reconstruction (namely, HEATHER). HEATHER was created from serially sectioned images of the female Visible Human Project dataset to encompass a total of 12 different tissues, and included computer-aided design geometries of the cochlear implant. Since existing methods were unable to generate the required complexity for HEATHER, a new modeling workflow was proposed. The results of the finite-element analysis agree with the literature, showing that the injected current exits the cochlea via the modiolus (14%), the basal end of the cochlea (22%), and through the cochlear walls (64%). It was also found that, once leaving the cochlea, the current travels to the implant body via the cranial cavity or scalp. The modeling workflow proved to be robust and flexible, allowing for meshes to be generated with substantial user control. Furthermore, the workflow could easily be employed to create realistic anatomical models of the human head for different bioelectric applications, such as deep brain stimulation, electroencephalography, and other biophysical phenomena.

Retention of ion-implanted-xenon in olivine: Dependence on implantation dose

NASA Technical Reports Server (NTRS)

Melcher, C. L.; Tombrello, T. A.; Burnett, D. S.

1982-01-01

The diffusion of Xe in olivine, a major mineral in both meteorites and lunar samples, was studied. Xe ions were implanted at 200 keV into single-crystal synthetic-forsterite targets and the depth profiles were measured by alpha particle backscattering before and after annealing for 1 hour at temperatures up to 1500 C. The fraction of implanted Xe retained following annealing was strongly dependent on the implantation dose. Maximum retention of 100% occurred for an implantion dose of 3 x 10 to the 15th power Xe ions/sq cm. Retention was less at lower doses, with (approximately more than or = 50% loss at one hundred trillion Xe ions/sq cm. Taking the diffusion coefficient at this dose as a lower limit, the minimum activation energy necessary for Xe retention in a 10 micrometer layer for ten million years was calculated as a function of metamorphic temperature.

Three types of dermal grafts in rats: the importance of mechanical property and structural design.

PubMed

You, Chuangang; Wang, Xingang; Zheng, Yurong; Han, Chunmao

2013-12-04

To determine how the mechanical property and micro structure affect tissue regeneration and angiogenesis, three types of scaffolds were studied. Acellular dermal matrices (ADM), produced from human skin by removing the epidermis and cells, has been widely used in wound healing because of its high mechanical strength. Collagen scaffolds (CS) incorporated with poly(glycolide-co-L-lactide) (PLGA) mesh forms a well-supported hybrid dermal equivalent poly(glycolide-co-L-lactide) mesh/collagen scaffolds (PMCS). We designed this scaffold to enhance the CS mechanical property. These three different dermal substitutes-ADM, CS and PMCSs are different in the tensile properties and microstructure. Several basic physical characteristics of dermal substitutes were investigated in vitro. To characterize the angiogenesis and tissue regeneration, the materials were embedded subcutaneously in Sprague-Dawley (SD) rats. At weeks 1, 2, 4 and 8 post-surgery, the tissue specimens were harvested for histology, immunohistochemistry and real-time quantitative PCR (RT-qPCR). In vitro studies demonstrated ADM had a higher Young's modulus (6.94 MPa) rather than CS (0.19 MPa) and PMCS (3.33 MPa) groups in the wet state. Compared with ADMs and CSs, PMCSs with three-dimensional porous structures resembling skin and moderate mechanical properties can promote tissue ingrowth more quickly after implantation. In addition, the vascularization of the PMCS group is more obvious than that of the other two groups. The incorporation of a PLGA knitted mesh in CSs can improve the mechanical properties with little influence on the three-dimensional porous microstructure. After implantation, PMCSs can resist the contraction and promote cell infiltration, neotissue formation and blood vessel ingrowth, especially from the mesh side. Although ADM has high mechanical strength, its vascularization is poor because the pore size is too small. In conclusion, the mechanical properties of scaffolds are important for maintaining the three-dimensional microarchitecture of constructs used to induce tissue regeneration and vascularization. The results illustrated that tissue regeneration requires the proper pore size and an appropriate mechanical property like PMCS which could satisfy these conditions to sustain growth.

Three types of dermal grafts in rats: the importance of mechanical property and structural design

PubMed Central

2013-01-01

Background To determine how the mechanical property and micro structure affect tissue regeneration and angiogenesis, three types of scaffolds were studied. Acellular dermal matrices (ADM), produced from human skin by removing the epidermis and cells, has been widely used in wound healing because of its high mechanical strength. Collagen scaffolds (CS) incorporated with poly(glycolide-co-L-lactide) (PLGA) mesh forms a well-supported hybrid dermal equivalent poly(glycolide-co-L-lactide) mesh/collagen scaffolds (PMCS). We designed this scaffold to enhance the CS mechanical property. These three different dermal substitutes—ADM, CS and PMCSs are different in the tensile properties and microstructure. Methods Several basic physical characteristics of dermal substitutes were investigated in vitro. To characterize the angiogenesis and tissue regeneration, the materials were embedded subcutaneously in Sprague–Dawley (SD) rats. At weeks 1, 2, 4 and 8 post-surgery, the tissue specimens were harvested for histology, immunohistochemistry and real-time quantitative PCR (RT-qPCR). Results In vitro studies demonstrated ADM had a higher Young’s modulus (6.94 MPa) rather than CS (0.19 MPa) and PMCS (3.33 MPa) groups in the wet state. Compared with ADMs and CSs, PMCSs with three-dimensional porous structures resembling skin and moderate mechanical properties can promote tissue ingrowth more quickly after implantation. In addition, the vascularization of the PMCS group is more obvious than that of the other two groups. The incorporation of a PLGA knitted mesh in CSs can improve the mechanical properties with little influence on the three-dimensional porous microstructure. After implantation, PMCSs can resist the contraction and promote cell infiltration, neotissue formation and blood vessel ingrowth, especially from the mesh side. Although ADM has high mechanical strength, its vascularization is poor because the pore size is too small. In conclusion, the mechanical properties of scaffolds are important for maintaining the three-dimensional microarchitecture of constructs used to induce tissue regeneration and vascularization. Conclusion The results illustrated that tissue regeneration requires the proper pore size and an appropriate mechanical property like PMCS which could satisfy these conditions to sustain growth. PMID:24304500

Safety of Synthetic Glue Used for Laparoscopic Prolapse Treatment.

PubMed

Sarasa Castelló, Núria; Toth, Alexandra; Canis, Michel; Botchorishvilli, Revaz

2017-12-29

We detected mesh erosion and serious postoperative complications in 3 women after performing laparoscopic promontofixation (LPF) using glue for mesh fixation. Glue, largely used in hernia surgery repair, is proposed by some gynecologic surgeons because it saves time and is easier to use than traditional sutures. We report 3 cases of postoperative complications after LPF in which glue had been used and provide research in the published literature about the use of glue in LPF. A research of glue use in gynecology mesh fixation was performed through PubMed on October 2016. The search was done using the Medical Subject Heading terms "POP" & "Laparoscopy" & "surgical Mesh" and the word either "glue" or "adhesive. Only 2 articles were found: Willecocq et al [1] and Estrade et al [2]. Neither study focused on postoperative complications. In this publication, we accurately edited video surgeries with an instructive purpose. University Hospital of Clermont-Ferrand, France. Patient A, a 65-year-old woman, complained of pelvic pain and vaginal discharge 1 month after LPF (polypropylene mesh and glue had been used). Wall mesh exposure and purulent discharge were noted. She received antibiotics and underwent mesh ablation surgery; debris of the glue was easily identified. Patient B, a 65-year-old lady with previous hysterectomy consulted for a bulging feeling in her vagina (classification: cystocele +2; rectocele +3 stage). An LPF was performed using polypropylene soft nonabsorbable mesh and glue. One month later, an apical defect of vaginal epithelialization was detected; she received long estrogenic local treatment but had to undergo surgery when presenting malodorous discharge and mesh exposure. The exposed mesh was removed, and pieces of glue were identified, having avoided mesh attachment. Patient C had a previous abdominal hysterectomy and promontofixation using a polyester mesh with glue. She consulted to us for vaginal mesh erosion covered with purulent discharge 3.5 years after LPF in another center. At the surgery, 1 cm of the prosthesis was identified in the vagina, dissected, and sutured. One year later, she consulted for dyspareunia and purulent discharge; vaginal rigid mesh exposure with an epithelization defect and inflammatory signs was seen. During laparoscopy, prosthetic exposition and glue debris on the prosthesis were identified. In all 3 cases, debris of glue were identified in the no integrated mesh area. The suggested reasons of exposure can be the excessive amount of surgical glue applied. Moreover, a large amount of glue may be impairing tissue ingrowth through the mesh pores, causing low fibrosis and poor tissue integration [3]. Glue seems to prevent fibrosis from occurring. Its use in pelvic organ prolapse laparoscopic mesh fixation should be done with caution. No prospective studies reporting long-term comorbidities and results have been published. Copyright © 2017 American Association of Gynecologic Laparoscopists. Published by Elsevier Inc. All rights reserved.

Mesh repair of umbilical hernia without a visible abdominal scar.

PubMed

Kurpiewski, Waldemar; Kiliańczyk, Michał; Szynkarczuk, Rafał; Tenderenda, Michał

2014-02-01

Experience in the use of Single Incision Laparoscopic Surgery procedures and the persistent urge to improve the cosmetic effect have contributed to the introduction of mesh repair of an umbilical hernia by means of a small incision in the natural position of the umbilicus. The aim of the study was to present the surgical technique and assess its postoperative results. During the period between 24.08.2011 and 01.01.2013, twenty-three umbilical hernia repair operations with the use of a polypropylene mesh by means of a small incision in the natural position of the umbilicus were performed. The synthetic material was placed in the preperitoneal space. The wound was closed and the umbilicus was reconstructed simultaneously, in order to make the scar invisible. Cutaneous stitches were not used. The average duration of the operation was 49 minutes. In one case of an obese patient with coexisting linea alba dehiscence, hernia recurrence was observed. All wounds healed without complications. The cosmetic effect was very good. Based on the presented experience mesh repair of the umbilical hernia by means of a small incision in the natural position of the umbilicus contributes essential benefits, such as a very good cosmetic effect without consecutive increasing costs, as compared to standard treatment by means of an infraumbilical incision.

An evaluation of hernia education in surgical residency programs.

PubMed

Hope, W W; O'Dwyer, B; Adams, A; Hooks, W B; Kotwall, C A; Clancy, T V

2014-08-01

The purpose of this study was to evaluate surgical residents' educational experience related to ventral hernias. A 16-question survey was sent to all program coordinators to distribute to their residents. Consent was obtained following a short introduction of the purpose of the survey. Comparisons based on training level were made using χ(2) test of independence, Fisher's exact, and Fisher's exact with Monte Carlo estimate as appropriate. A p value <0.05 was considered significant. The survey was returned by 183 residents from 250 surgical programs. Resident postgraduate year (PG-Y) level was equivalent among groups. Preferred techniques for open ventral hernia varied; the most common (32 %) was intra-abdominal placement of mesh with defect closure. Twenty-two percent of residents had not heard of the retrorectus technique for hernia repair, 48 % had not performed the operation, and 60 % were somewhat comfortable with and knew the general categories of mesh prosthetics products. Mesh choices, biologic and synthetic, varied among the different products. The most common type of hernia education was teaching in the operating room in 87 %, didactic lecture 69 %, and discussion at journal club 45 %. Number of procedures, comfort level with open and laparoscopic techniques, indications for mesh use and technique, familiarity and use of retrorectus repair, and type of hernia education varied significantly based on resident level (p < 0.05). Exposure to hernia techniques and mesh prosthetics in surgical residency programs appears to vary. Further evaluation is needed and may help in standardizing curriculums for hernia repair for surgical residents.

The Endocannabinoid System as a Target for Treatment of Breast Cancer

DTIC Science & Technology

2010-08-01

psychoactive constituent of marijuana (Gaoni and Mechoulam, 1964), as well as other naturally occurring and synthetically derived cannabinoids bind to and...the primary psychoactive constituent present in marijuana , and WIN55,212-2, a highly potent, full CB1 receptor agonist. Female mice implanted with...potent and highly efficacious synthetic cannabinoid receptor agonist originally developed as a nonsteroidal anti-inflammatory drug (Ward et al., 1991

Preliminary Study of Hiatal Hernia Repair Using Polyglycolic Acid: Trimethylene Carbonate Mesh

PubMed Central

Singh, Tejinder P.; Dunnican, Ward J.; Binetti, Brian R.

2012-01-01

Background: Repairing large hiatal hernias using mesh has been shown to reduce recurrence. Drawbacks to mesh include added time to place and secure the prosthesis as well as complications such as esophageal erosion. We used a laparoscopic technique for repair of hiatal hernias (HH) >5cm, incorporating primary crural repair with onlay fixation of a synthetic polyglycolicacid:trimethylene carbonate (PGA:TMC) absorbable tissue reinforcement. The purpose of this report is to present short-term follow-up data. Methods: Patients with hiatal hernia types I-III and defects >5cm were included. Primary closure of the hernia defect was performed using interrupted nonpledgeted sutures, followed by PGA:TMC mesh onlay fixed with absorbable tacks. A fundoplication was then performed. Evaluation of patients was carried out at routine follow-up visits. Outcomes measured were symptoms of gastroesophageal reflux disease (GERD), or other symptoms suspicious for recurrence. Patients exhibiting these complaints underwent further evaluation including radiographic imaging and endoscopy. Results: Follow-up data were analyzed on 11 patients. Two patients were male; 9 were female. The mean age was 60 years. The mean length of follow-up was 13 months. There were no complications related to the mesh. One patient suffered from respiratory failure, one from gas bloat syndrome, and another had a superficial port-site infection. One patient developed a recurrent hiatal hernia. Conclusions: In this small series, laparoscopic repair of hiatal hernias >5cm with onlay fixation of PGA:TMC tissue reinforcement has short-term outcomes with a reasonably low recurrence rate. However, due to the preliminary and nonrandomized nature of the data, no strong comparison can be made with other types of mesh repairs. Additional data collection is warranted. PMID:22906331

Effect of different types of prosthetic platforms on stress-distribution in dental implant-supported prostheses.

PubMed

Minatel, Lurian; Verri, Fellippo Ramos; Kudo, Guilherme Abu Halawa; de Faria Almeida, Daniel Augusto; de Souza Batista, Victor Eduardo; Lemos, Cleidiel Aparecido Araujo; Pellizzer, Eduardo Piza; Santiago, Joel Ferreira

2017-02-01

A biomechanical analysis of different types of implant connections is relevant to clinical practice because it may impact the longevity of the rehabilitation treatment. Therefore, the objective of this study is to evaluate the Morse taper connections and the stress distribution of structures associated with the platform switching (PSW) concept. It will do this by obtaining data on the biomechanical behavior of the main structure in relation to the dental implant using the 3-dimensional finite element methodology. Four models were simulated (with each containing a single prosthesis over the implant) in the molar region, with the following specifications: M1 and M2 is an external hexagonal implant on a regular platform; M3 is an external hexagonal implant using PSW concept; and M4 is a Morse taper implant. The modeling process involved the use of images from InVesalius CT (computed tomography) processing software, which were refined using Rhinoceros 4.0 and SolidWorks 2011 CAD software. The models were then exported into the finite element program (FEMAP 11.0) to configure the meshes. The models were processed using NeiNastram software. The main results are that M1 (regular diameter 4mm) had the highest stress concentration area and highest microstrain concentration for bone tissue, dental implants, and the retaining screw (P<0.05). Using the PSW concept increases the area of the stress concentrations in the retaining screw (P<0.05) more than in the regular platform implant. It was concluded that the increase in diameter is beneficial for stress distribution and that the PSW concept had higher stress concentrations in the retaining screw and the crown compared to the regular platform implant. Copyright © 2016 Elsevier B.V. All rights reserved.

Internal Motion Estimation by Internal-external Motion Modeling for Lung Cancer Radiotherapy.

PubMed

Chen, Haibin; Zhong, Zichun; Yang, Yiwei; Chen, Jiawei; Zhou, Linghong; Zhen, Xin; Gu, Xuejun

2018-02-27

The aim of this study is to develop an internal-external correlation model for internal motion estimation for lung cancer radiotherapy. Deformation vector fields that characterize the internal-external motion are obtained by respectively registering the internal organ meshes and external surface meshes from the 4DCT images via a recently developed local topology preserved non-rigid point matching algorithm. A composite matrix is constructed by combing the estimated internal phasic DVFs with external phasic and directional DVFs. Principle component analysis is then applied to the composite matrix to extract principal motion characteristics, and generate model parameters to correlate the internal-external motion. The proposed model is evaluated on a 4D NURBS-based cardiac-torso (NCAT) synthetic phantom and 4DCT images from five lung cancer patients. For tumor tracking, the center of mass errors of the tracked tumor are 0.8(±0.5)mm/0.8(±0.4)mm for synthetic data, and 1.3(±1.0)mm/1.2(±1.2)mm for patient data in the intra-fraction/inter-fraction tracking, respectively. For lung tracking, the percent errors of the tracked contours are 0.06(±0.02)/0.07(±0.03) for synthetic data, and 0.06(±0.02)/0.06(±0.02) for patient data in the intra-fraction/inter-fraction tracking, respectively. The extensive validations have demonstrated the effectiveness and reliability of the proposed model in motion tracking for both the tumor and the lung in lung cancer radiotherapy.

The Use of Ion Implantation for Materials Processing.

DTIC Science & Technology

1982-07-02

corrosion studies. i this application main shaft bearings for turbojet engirps are being implanted to impart corrosion resistance to the rolling element...following discussion. Steels of this composition can be deep harened to Rockwell C-65 when quenched from the austenitizing temperature of 1230 C. An oil ...lubricant was a synthetic polyester lubricant used for turbojet engine bearings. As can be seen in Fig. 16 the wear rate after running-in is a factor

Cost of ventral hernia repair using biologic or synthetic mesh.

PubMed

Totten, Crystal F; Davenport, Daniel L; Ward, Nicholas D; Roth, J Scott

2016-06-15

Patients undergoing ventral hernia repair (VHR) with biologic mesh (BioM) have higher hospital costs compared with synthetic mesh (SynM). This study compares 90-d pre- and post-VHR hospital costs (180-d) among BioM and SynM based on infection risk. This retrospective National Surgical Quality Improvement Program study matched patient perioperative risk with resource utilization cost for a consecutive series of VHR repairs. Patient infection risks, clinical and financial outcomes were compared in unmatched SynM (n = 303) and BioM (n = 72) groups. Propensity scores were used to match 35 SynM and BioM pairs of cases with similar infection risk for outcomes analysis. BioM patients in the unmatched group were older with higher American Society of Anesthesiologists (ASA) and wound classification, and they more frequently underwent open repairs for recurrent hernias. Wound surgical site infections were more frequent in unmatched BioM patients (P = 0.001) as were 180-d costs ($43.8k versus $14.0k, P < 0.001). Propensity matching resulted in 31 clean cases. In these low-risk patients, wound occurrences and readmissions were identical, but 180-d costs remained higher ($31.8k versus $15.5k, P < 0.001). There were no differences in hospital 180-d diagnostic, emergency room, intensive care unit, floor, pharmacy, or therapeutic costs. However, 180-d operating room services and supply costs were higher in the BioM group ($21.1k versus $7.1k, P < 0.001). BioM is used more commonly in hernia repairs involving higher wound class and ASA scores and recurrent hernias. Clinical outcomes after low-risk VHRs are similar; SynM utilization in low-risk hernia repairs was more cost-effective. Published by Elsevier Inc.

Quickening: Translational design of resorbable synthetic vascular grafts.

PubMed

Stowell, Chelsea E T; Wang, Yadong

2018-08-01

Traditional tissue-engineered vascular grafts have yet to gain wide clinical use. The difficulty of scaling production of these cell- or biologic-based products has hindered commercialization. In situ tissue engineering bypasses such logistical challenges by using acellular resorbable scaffolds. Upon implant, the scaffolds become remodeled by host cells. This review describes the scientific and translational advantages of acellular, synthetic vascular grafts. It surveys in vivo results obtained with acellular synthetics over their fifty years of technological development. Finally, it discusses emerging principles, highlights strategic considerations for designers, and identifies questions needing additional research. Copyright © 2018 Elsevier Ltd. All rights reserved.

Do Clinical and Radiological Assessments Contribute to the Understanding of Biomaterials? Results From a Prospective Randomized Sinus Augmentation Split-Mouth Trial.

PubMed

Lorenz, Jonas; Korzinskas, Tadas; Chia, Poju; Maawi, Sarah Al; Eichler, Katrin; Sader, Robert A; Ghanaati, Shahram

2018-02-01

The present prospective randomized split-mouth trial reports on the 3-year clinical and radiological follow-up investigation of implants placed 7 months after sinus augmentation with 2 different bone substitute materials. The aim of the study was to complete the histologic observation of cellular reactions by analyses of the implants and the volumetric changes of the augmented bone substitute materials. A sinus augmentation split-mouth trial was performed in 14 patients with the synthetic bone substitute material Nanobone (NB) and the xenogeneic Bio-Oss (BO). Changes in volume and density of the augmented biomaterials were investigated by analysis of computed tomography scans, taken immediately after augmentation and after 7 months. Clinical implant parameters were assessed after 3 years of loading. Both bone substitute materials underwent nonsignificant volume reduction and significant increase in bone density over an integration period of 7 months. No significant differences concerning volume and bone density were observed between the groups. Three years after loading, 51 of 53 implants were in situ with no peri-implant infections, and only a few soft-tissue variations were present. The present prospective randomized study showed that no differences could be observed clinically and radiologically. Accordingly, it seems that both biomaterials, independent of their physicochemical composition, enable clinical success and long-time stability for dental implants. Interestingly, the histological results showed distinct differences in cellular reactions: While the xenogeneic BO induced a mild tissue reaction with only few multinucleated giant cells and comparably low vascularization, the synthetic NB induced a multinucleated giant cell-triggered tissue reaction with an increase of vascularization. Thus, the present study showed that a combination analysis-histological, clinical, and radiological-is necessary for a detailed assessment of a biomaterial's quality for clinical application.

Flexible transparent conducting films with embedded silver networks composed of bimodal-sized nanoparticles for heater application.

PubMed

Park, Ji Sun; Song, Yookyung; Park, Daseul; Kim, Yeon-Won; Kim, Yoon Jin

2018-06-22

A facile one-pot synthetic method for preparing the Ag nanoparticle inks with a bimodal size distribution was newly devised and they were successfully employed as a conducting filler to form the metal-mesh type transparent conducting electrodes on the flexible substrate. Bimodal-sized Ag nanoparticles were synthesized through the polyol process, and their size variation was occurred via finely tuned composition ratio between Ag + ions and polymeric capping agents. The prepared bimodal-sized Ag nanoparticles exhibited the form of well-dispersed Ag nanoparticle inks without adding any dispersants and dispersion process. By filling the patterned micro-channels engraved on the flexible polymer substrate using a bimodal-sized Ag nanoparticle ink, a metal-mesh type transparent electrode (transmittance: 90% at 550 nm, haze: 1.5, area: 8 × 8 cm 2 ) was fabricated. By applying DC voltage to the mesh type electrode, a flexible transparent joule heater was successfully achieved with a performance of 4.5 °C s -1 heat-up rate at a low input power density.

Reconstruction of the pelvic floor and perineum with human acellular dermal matrix and thigh flaps following pelvic exenteration.

PubMed

Said, Hakim K; Bevers, Michael; Butler, Charles E

2007-12-01

Patients who undergo pelvic floor resection as treatment for recurrent cancer following radiation therapy have increased rates of complications, particularly if permanent prosthetic mesh is used for reconstruction. Human acellular dermal matrix (HADM), commonly used for reconstruction in other torso locations, is associated with lower rates of complications (including infection, adhesions and cutaneous exposure) than synthetic mesh. We describe an effective technique to reconstruct the pelvic floor and perineum with HADM and thigh-based flaps following pelvic exenteration and radical vulvectomy. A 75-year-old woman underwent radical resection of the pelvic floor and perineum to treat recurrent vulvar squamous cell carcinoma and osteoradionecrosis. The pelvic floor and perineal soft tissue defect were reconstructed with HADM (AlloDerm; LifeCell Corporation, Branchburg, NJ) and bilateral, thigh-based tissue flaps, respectively. Despite a large resection, previous irradiation therapy and bacterial contamination the wounds healed without complications. Reconstruction of pelvic floor defects using HADM is an option when wound conditions are unfavorable for the use of permanent prosthetic meshes.

Flexible transparent conducting films with embedded silver networks composed of bimodal-sized nanoparticles for heater application

NASA Astrophysics Data System (ADS)

Park, Ji Sun; Song, Yookyung; Park, Daseul; Kim, Yeon-Won; Kim, Yoon Jin

2018-06-01

A facile one-pot synthetic method for preparing the Ag nanoparticle inks with a bimodal size distribution was newly devised and they were successfully employed as a conducting filler to form the metal-mesh type transparent conducting electrodes on the flexible substrate. Bimodal-sized Ag nanoparticles were synthesized through the polyol process, and their size variation was occurred via finely tuned composition ratio between Ag+ ions and polymeric capping agents. The prepared bimodal-sized Ag nanoparticles exhibited the form of well-dispersed Ag nanoparticle inks without adding any dispersants and dispersion process. By filling the patterned micro-channels engraved on the flexible polymer substrate using a bimodal-sized Ag nanoparticle ink, a metal-mesh type transparent electrode (transmittance: 90% at 550 nm, haze: 1.5, area: 8 × 8 cm2) was fabricated. By applying DC voltage to the mesh type electrode, a flexible transparent joule heater was successfully achieved with a performance of 4.5 °C s‑1 heat-up rate at a low input power density.

Graph Partitioning for Parallel Applications in Heterogeneous Grid Environments

NASA Technical Reports Server (NTRS)

Bisws, Rupak; Kumar, Shailendra; Das, Sajal K.; Biegel, Bryan (Technical Monitor)

2002-01-01

The problem of partitioning irregular graphs and meshes for parallel computations on homogeneous systems has been extensively studied. However, these partitioning schemes fail when the target system architecture exhibits heterogeneity in resource characteristics. With the emergence of technologies such as the Grid, it is imperative to study the partitioning problem taking into consideration the differing capabilities of such distributed heterogeneous systems. In our model, the heterogeneous system consists of processors with varying processing power and an underlying non-uniform communication network. We present in this paper a novel multilevel partitioning scheme for irregular graphs and meshes, that takes into account issues pertinent to Grid computing environments. Our partitioning algorithm, called MiniMax, generates and maps partitions onto a heterogeneous system with the objective of minimizing the maximum execution time of the parallel distributed application. For experimental performance study, we have considered both a realistic mesh problem from NASA as well as synthetic workloads. Simulation results demonstrate that MiniMax generates high quality partitions for various classes of applications targeted for parallel execution in a distributed heterogeneous environment.

[An experimental study of successful tracheal replacement using pedicled latissimus dorsi muscle flap and soft Marlex mesh].

PubMed

Hayashi, A

1991-02-01

The present experimental study was undertaken to evaluate the efficacy of combined latissimus dorsi muscle flap and soft Marlex mesh in the reconstruction of the trachea. Thirty-one mongrel dogs underwent a two-stage operation. In the first stage operation, they were divided into four groups for implanting a different prosthesis. A silicone rod was used as the core and this was rolled with soft Marlex mesh to make a prosthesis (Group A and B: without reinforce, Group C: reinforced by wrapping stainless steel mesh, Group D: reinforced with helical stain steel wire). The latissimus dorsi muscle flap was rolled circumferentially around the prosthesis and it was left in place for a period of 4 to 6 weeks. In the second stage operation, the long pedicled muscle flap with the biologically organized prosthesis was mobilized to be guided into the cervix, and the tracheal reconstruction was done with them following circumferential tracheal resection. In result, five of six dogs of group D survived more than 6 months after the replacement without anastomotic leakage or stenosis causing inflammatory granulation. Organization with neo-vascularity of the prosthesis at the time of the tracheal reconstruction was important firstly to avoid incurring complications concerning anastomosis and secondly for long-term stability of the healing and epithelialization of the prosthesis.

ENUCLEATION IN MALIGNANT CHOROIDAL MELANOMA - results in 15 years of using a new material in the prosthesis of the orbital cavity

PubMed Central

Tataru, CP; Pop, MD

2012-01-01

Rationale: Enucleation implants are covered with a material that allows the fixation of the extraocular rectus muscles. Usually, the implants are covered in donor sclera, which implies the risk of infection transmission, inflammation and implant rejection, being also an expensive procedure. The new materials used for implant meshing should be tested and a safer and cost effective solution should be researched. Objective: This study presents the results obtained after a 15-year use of an original prosthesis for the reconstruction of the orbital cavity after enucleation surgery. Methods and results: 42 eyes of 42 patients who underwent enucleation surgery for choroidal malignant melanoma were included in the study. The surgical technique was very similar to the classic enucleation, the major difference being the implant of a prosthesis made out of a Polymethyl methacrylate (PMMA) ball covered by a Polyethylene terephthalate (dacron) shell used in cardiovascular surgery. All the patients had a very good technical result, without the inflammation of the orbital cavity, conjunctiva or eyelids, which demonstrates a very high material tolerability and an excellent cosmetic result. Late implant expulsion appeared in 7.14% of the patients (3 cases). Discussion: The particularly good results obtained by using this technique, the absence of an inflammatory reaction after surgery, and the long lasting stability of the implant, recommend the method as being safe, with no major complications and a good esthetic result. AbbreviationsPolymethyl methacrylate (PMMA), Malignant choroidal melanoma (CMM) PMID:22802888

Synthesis and Characterisation of Photocrosslinked poly(ethylene glycol) diacrylate Implants for Sustained Ocular Drug Delivery.

PubMed

McAvoy, Kathryn; Jones, David; Thakur, Raghu Raj Singh

2018-01-16

To investigate the sustained ocular delivery of small and large drug molecules from photocrosslinked poly(ethylene glycol) diacrylate (PEGDA) implants with varying pore forming agents. Triamcinolone acetonide and ovalbumin loaded photocrosslinked PEGDA implants, with or without pore-forming agents, were fabricated and characterised for chemical, mechanical, swelling, network parameters, as well as drug release and biocompatibility. HPLC-based analytical methods were employed for analysis of two molecules; ELISA was used to demonstrate bioactivity of ovalbumin. Regardless of PEGDA molecular weight or pore former composition all implants loaded with triamcinolone acetonide released significantly faster than those loaded with ovalbumin. Higher molecular weight PEGDA systems (700 Da) resulted in faster drug release of triamcinolone acetonide than their 250 Da counterpart. All ovalbumin released over the 56-day time period was found to be bioactive. Increasing PEGDA molecular weight resulted in increased system swelling, decreased crosslink density (Ve), increased polymer-water interaction parameter (χ), increased average molecular weight between crosslinks (Mc) and increased mesh size (ε). SEM studies showed the porosity of implants increased with increasing PEGDA molecular weight. Biocompatibility showed both PEGDA molecular weight implants were non-toxic when exposed to retinal epithelial cells over a 7-day period. Photocrosslinked PEGDA implant based systems are capable of controlled drug release of both small and large drug molecules through adaptations in the polymer system network. We are currently continuing evaluation of these systems as potential sustained drug delivery devices.

The efficacy of maxillary protraction protocols with the micro-implant-assisted rapid palatal expander (MARPE) and the novel N2 mini-implant-a finite element study.

PubMed

Moon, Won; Wu, Kimberley W; MacGinnis, Matthew; Sung, Jay; Chu, Howard; Youssef, George; Machado, Andre

2015-01-01

Maxillary protraction with the novel N2 mini-implant- and micro-implant-assisted rapid palatal expander (MARPE) can potentially provide significant skeletal effects without surgery, even in older patients where conventional facemask therapy has limited skeletal effects. However, the skeletal effects of altering the location and direction of force from mini-implant-assisted maxillary protraction have not been extensively analyzed. In this study, the application of the novel N2 mini-implant as an orthopedic anchorage device is explored in its ability to treat patients with class III malocclusions. A 3D cranial mesh model with associated sutures was developed from CT images and Mimics modeling software. Utilizing ANSYS simulation software, protraction forces were applied at different locations and directions to simulate conventional facemask therapy and seven maxillary protraction protocols utilizing the novel N2 mini-implant. Stress distribution and displacement were analyzed. Video animations and superimpositions were created. By changing the vector of force and location of N2 mini-implant, the maxilla was displaced differentially. Varying degrees of forward, downward, and rotational movements were observed in each case. For brachyfacial patients, anterior micro-implant-supported protraction at -45° or intermaxillary class III elastics at -45° are recommended. For dolicofacial patients, either anterior micro-implants at -15° or an intermaxillary spring at +30° is recommended. For mesofacial patients with favorable vertical maxillary position, palatal micro-implants at -30° are recommended; anterior micro-implants at -30° are preferred for shallow bites. For patients with a severe mid-facial deficiency, intermaxillary class III elastics at -30° are most effective in promoting anterior growth of the maxilla. By varying the location of N2 mini-implants and vector of class III mechanics, clinicians can differentially alter the magnitude of forward, downward, and rotational movement of the maxilla. As a result, treatment protocol can be customized for each unique class III patient.

Marine magnetotelluric inversion with an unstructured tetrahedral mesh

NASA Astrophysics Data System (ADS)

Usui, Yoshiya; Kasaya, Takafumi; Ogawa, Yasuo; Iwamoto, Hisanori

2018-05-01

The finite element method using an unstructured tetrahedral mesh is one of the most effective methods for the three-dimensional modelling of marine magnetotelluric data which are strongly affected by bathymetry, because it enables us to incorporate both small-scale and regional-scale bathymetry into a computational mesh with a practical number of elements. The authors applied a three-dimensional inversion scheme using mesh of this type to marine magnetotelluric problems for the first time and verified its applicability. Forward calculations for two bathymetry models demonstrated that the results obtained with an unstructured tetrahedral mesh are close to the reference solutions. To evaluate the forward calculation results, we developed a general TM-mode analytical formulation for a two-dimensional sinusoidal topography. Moreover, synthetic inversion test results confirmed that a three-dimensional inversion scheme with an unstructured tetrahedral mesh enables us to recover subseafloor resistivity structure properly even for a model including a land-sea boundary as well as seafloor undulations. The verified inversion scheme was subsequently applied to a set of marine magnetotelluric data observed around the Iheya North Knoll, the middle Okinawa Trough. Three-dimensional modelling using a mesh with precise bathymetry demonstrated that the data observed around the Iheya North Knoll are strongly affected by bathymetry, especially by the sea-depth differences between the depression of the trough and the shallow East China Sea. The estimated resistivity structure under the knoll is characterized by a conductive surface layer underlain by a resistive layer. The conductive layer implies permeable pelagic/hemi-pelagic sediments, which are consistent with a previous seismological study. Furthermore, the conductive layer has a resistive part immediately below the knoll, which is regarded as the consolidated magma intrusion that formed the knoll. Furthermore, at depth of 10 km, we found that the resistor underneath the knoll extends to the southeast, implying that subseafloor resistivity under the Volcanic Arc Migration Phenomenon (VAMP) area is more resistive than the surroundings due to the presence of consolidated magma.

Enhanced bioactive scaffolds for bone tissue regeneration

NASA Astrophysics Data System (ADS)

Karnik, Sonali

Bone injuries are commonly termed as fractures and they vary in their severity and causes. If the fracture is severe and there is loss of bone, implant surgery is prescribed. The response to the implant depends on the patient's physiology and implant material. Sometimes, the compromised physiology and undesired implant reactions lead to post-surgical complications. [4, 5, 20, 28] Efforts have been directed towards the development of efficient implant materials to tackle the problem of post-surgical implant failure. [ 15, 19, 24, 28, 32]. The field of tissue engineering and regenerative medicine involves the use of cells to form a new tissue on bio-absorbable or inert scaffolds. [2, 32] One of the applications of this field is to regenerate the damaged or lost bone by using stem cells or osteoprogenitor cells on scaffolds that can integrate in the host tissue without causing any harmful side effects. [2, 32] A variety of natural, synthetic materials and their combinations have been used to regenerate the damaged bone tissue. [2, 19, 30, 32, 43]. Growth factors have been supplied to progenitor cells to trigger a sequence of metabolic pathways leading to cellular proliferation, differentiation and to enhance their functionality. [56, 57] The challenge persists to supply these proteins, in the range of nano or even picograms, and in a sustained fashion over a period of time. A delivery system has yet to be developed that would mimic the body's inherent mechanism of delivering the growth factor molecules in the required amount to the target organ or tissue. Titanium is the most preferred metal for orthopedic and orthodontic implants. [28, 46, 48] Even though it has better osteogenic properties as compared to other metals and alloys, it still has drawbacks like poor integration into the surrounding host tissue leading to bone resorption and implant failure. [20, 28, 35] It also faces the problem of postsurgical infections that contributes to the implant failure. [26, 37]. The focus of this dissertation was to design and develop novel implant materials for coating titanium to improve its biological properties. These natural and/or semi-synthetic materials improved cellular adhesion, biological response to the scaffolds and prevented growth of bacteria when they were enhanced with growth factor and anti-infective loaded nanotubes. The implant materials showed promise when tested in vitro for cell proliferation, differentiation and bacterial growth inhibition.

Global Convergence on the Bioethics of Surgical Implants

PubMed Central

Monlezun, Dominique J.

2015-01-01

The increasing globalization of mankind with pluralistic belief systems necessitates physicians by virtue of their profession to partner with bioethics for soundly applying emerging knowledge and technologies for the best use of the patient. A subfield within medicine in which this need is acutely felt is that of surgical implants. Within this subfield such recent promising ethics and medicine partnerships include the International Tissue Engineering Research Association and UNESCO Chair in Bioethics and Human Rights' International Code of Ethics. In this paper, we provide an overview of the emerging human rights framework from bioethics and international law, discussion of key framework principles, their application to the current surgical challenge of implantation of surgical mesh for prolapse, and conclusions and recommendations. Such discussions are meant to facilitate true quality improvement in patient care by ensuring the exciting technologies and medical practices emerging new daily are accompanied by an equal commitment of physicians to ethically provide their services for the chief end of the patient's good. PMID:25973426

Global convergence on the bioethics of surgical implants.

PubMed

Garcia, Alberto; Monlezun, Dominique J

2015-01-01

The increasing globalization of mankind with pluralistic belief systems necessitates physicians by virtue of their profession to partner with bioethics for soundly applying emerging knowledge and technologies for the best use of the patient. A subfield within medicine in which this need is acutely felt is that of surgical implants. Within this subfield such recent promising ethics and medicine partnerships include the International Tissue Engineering Research Association and UNESCO Chair in Bioethics and Human Rights' International Code of Ethics. In this paper, we provide an overview of the emerging human rights framework from bioethics and international law, discussion of key framework principles, their application to the current surgical challenge of implantation of surgical mesh for prolapse, and conclusions and recommendations. Such discussions are meant to facilitate true quality improvement in patient care by ensuring the exciting technologies and medical practices emerging new daily are accompanied by an equal commitment of physicians to ethically provide their services for the chief end of the patient's good.

Spider Silk Spun and Integrated into Composites

DTIC Science & Technology

2009-02-20

and elongation of sericin is lower than those of fibroin and, finally, (0 local shear damage is dominant in damaged sericin between fibres, while the... sericin at fibre-joint often shows microflow. These analytical studies are presently being expanded to include synthetic composites made of both...with sericin . Such a cocoon consists of three main parts: an outermost loose mesh structure, the middle shell layers and the innermost tetelette; all

Chronic Pain after Laparoscopic Transabdominal Preperitoneal Hernia Repair: A Randomized Comparison of Light and Extralight Titanized Polypropylene Mesh

PubMed Central

von Ahnen, Thomas; von Ahnen, Martin; Schardey, Hans

2010-01-01

Background The aim of this prospective, randomized, single-blinded clinical trial was to compare the incidence of chronic pain after laparoscopic transabdominal preperitoneal hernia repair (TAPP) using a 35-g/m2 titanized polypropylene mesh and a 16-g/m2 titanized polypropylene mesh. The reported incidence of chronic pain in patients who underwent laparoscopic hernia repair is a serious problem. The techniques of dissection, mesh fixation, and the mesh material used have all been identified as being part of the problem. Excellent biocompatibility through a unique combination of a lightweight open porous polypropylene mesh covered with a covalent-bonded titanium layer has been claimed. The aim of this study was to find out whether the titanium surface alone or the difference in material load between the two available meshes influences clinical outcomes. Methods Three hundred eighty patients with 466 inguinal hernias were operated on between 2002 and 2006 with the laparoscopic transabdominal preperitoneal (TAPP) technique. Mesh fixation with staples was carried out routinely. After the dissection was completed just prior to the implantation of the mesh, patients were randomized into two groups. In Group A, 250 (53.6%) inguinal hernias were repaired with a 35-g/m2 titanized polypropylene mesh, and in Group B, 216 (46.4%) inguinal hernias were repaired with a 16-g/m2 titanized polypropylene mesh. The primary outcome was chronic pain 3 years after surgery. The degree of pain was determined using a visual analog scale (VAS) with a range from 0 to 10. The secondary outcome was the rate of recurrence. Results The postoperative period of observation was at least 3 years for every patient. In both groups, 90% of the patients could be questioned and examined clinically: in Group A (Light), 5.3% of the patients and in Group B (Extralight), 1.5% of the patients suffered from chronic pain. Chronic pain was significantly more common in Group A than in Group B (p = 0.037). There was no difference with respect to the rate of recurrence: for Group A it was 3.1% and for Group B it was 2.6% (p = 0.724). Conclusions Chronic pain is not very common in patients who have had their inguinal hernias repaired with titanium-covered polypropylene mesh. Reducing the material load from 35 to 16 g/m2 seems to further improve the biocompatibility of these meshes, thus improving the clinical outcome by reducing chronic pain to a rare event. The role of staples in causing chronic pain following inguinal hernia repair may be overestimated. There was no evidence supporting the notion that the use of the 16-g/m2 titanized meshes is associated with increased recurrence rates. PMID:21103989

Perceptual “vowel spaces” of cochlear implant users: Implications for the study of auditory adaptation to spectral shift

PubMed Central

Harnsberger, James D.; Svirsky, Mario A.; Kaiser, Adam R.; Pisoni, David B.; Wright, Richard; Meyer, Ted A.

2012-01-01

Cochlear implant (CI) users differ in their ability to perceive and recognize speech sounds. Two possible reasons for such individual differences may lie in their ability to discriminate formant frequencies or to adapt to the spectrally shifted information presented by cochlear implants, a basalward shift related to the implant’s depth of insertion in the cochlea. In the present study, we examined these two alternatives using a method-of-adjustment (MOA) procedure with 330 synthetic vowel stimuli varying in F1 and F2 that were arranged in a two-dimensional grid. Subjects were asked to label the synthetic stimuli that matched ten monophthongal vowels in visually presented words. Subjects then provided goodness ratings for the stimuli they had chosen. The subjects’ responses to all ten vowels were used to construct individual perceptual “vowel spaces.” If CI users fail to adapt completely to the basalward spectral shift, then the formant frequencies of their vowel categories should be shifted lower in both F1 and F2. However, with one exception, no systematic shifts were observed in the vowel spaces of CI users. Instead, the vowel spaces differed from one another in the relative size of their vowel categories. The results suggest that differences in formant frequency discrimination may account for the individual differences in vowel perception observed in cochlear implant users. PMID:11386565

Dental implants in patients with oral mucosal diseases - a systematic review.

PubMed

Reichart, P A; Schmidt-Westhausen, A M; Khongkhunthian, P; Strietzel, F P

2016-05-01

To reveal dental implants survival rates in patients with oral mucosal diseases: oral lichen planus (OLP), Sjögren's syndrome (SjS), epidermolysis bullosa (EB) and systemic sclerosis (SSc). A systematic literature search using PubMed/Medline and Embase databases, utilising MeSH and search term combinations identified publications on clinical use implant-prosthetic rehabilitation in patients with OLP, SjS, EB, SSc reporting on study design, number, gender and age of patients, follow-up period exceeding 12 months, implant survival rate, published in English between 1980 and May 2015. After a mean observation period (mOP) of 53·9 months (standard deviation [SD] ±18·3), 191 implants in 57 patients with OLP showed a survival rate (SR) of 95·3% (SD ±21·2). For 17 patients with SjS (121 implants, mOP 48·6 ± 28·7 months), 28 patients with EB (165 implants, mOP 38·3 ± 16·9 months) and five patients with SSc (38 implants, mOP 38·3 ± 16·9 months), the respective SR was 91·7 ± 5·97% (SjS), 98·5 ± 2·7% (EB) and 97·4 ± 4·8% (SSc). Heterogeneity of data structure and quality of reporting outcomes did not allow for further comparative data analysis. For implant-prosthetic rehabilitation of patients suffering from OLP, SjS, EB and SSc, no evidence-based treatment guidelines are presently available. However, no strict contraindication for the placement of implants seems to be justified in patients with OLP, SjS, EB nor SSc. Implant survival rates are comparable to those of patients without oral mucosal diseases. Treatment guidelines as for dental implantation in patients with healthy oral mucosa should be followed. © 2015 John Wiley & Sons Ltd.

Bioglass implant-coating interactions in synthetic physiological fluids with varying degrees of biomimicry

PubMed Central

Popa, AC; Stan, GE; Husanu, MA; Mercioniu, I; Santos, LF; Fernandes, HR; Ferreira, JMF

2017-01-01

Synthetic physiological fluids are currently used as a first in vitro bioactivity assessment for bone grafts. Our understanding about the interactions taking place at the fluid–implant interface has evolved remarkably during the last decade, and does not comply with the traditional International Organization for Standardization/final draft International Standard 23317 protocol in purely inorganic simulated body fluid. The advances in our knowledge point to the need of a true paradigm shift toward testing physiological fluids with enhanced biomimicry and a better understanding of the materials’ structure-dissolution behavior. This will contribute to “upgrade” our vision of entire cascades of events taking place at the implant surfaces upon immersion in the testing media or after implantation. Starting from an osteoinductive bioglass composition with the ability to alleviate the oxidative stress, thin bioglass films with different degrees of polymerization were deposited onto titanium substrates. Their biomineralization activity in simulated body fluid and in a series of new inorganic–organic media with increasing biomimicry that more closely simulated the human intercellular environment was compared. A comprehensive range of advanced characterization tools (scanning electron microscopy; grazing-incidence X-ray diffraction; Fourier-transform infrared, micro-Raman, energy-dispersive, X-ray photoelectron, and surface-enhanced laser desorption/ionization time-of-flight mass spectroscopies; and cytocompatibility assays using mesenchymal stem cells) were used. The information gathered is very useful to biologists, biophysicists, clinicians, and material scientists with special interest in teaching and research. By combining all the analyses, we propose herein a step forward toward establishing an improved unified protocol for testing the bioactivity of implant materials. PMID:28176941

Bioglass implant-coating interactions in synthetic physiological fluids with varying degrees of biomimicry.

PubMed

Popa, A C; Stan, G E; Husanu, M A; Mercioniu, I; Santos, L F; Fernandes, H R; Ferreira, Jmf

2017-01-01

Synthetic physiological fluids are currently used as a first in vitro bioactivity assessment for bone grafts. Our understanding about the interactions taking place at the fluid-implant interface has evolved remarkably during the last decade, and does not comply with the traditional International Organization for Standardization/final draft International Standard 23317 protocol in purely inorganic simulated body fluid. The advances in our knowledge point to the need of a true paradigm shift toward testing physiological fluids with enhanced biomimicry and a better understanding of the materials' structure-dissolution behavior. This will contribute to "upgrade" our vision of entire cascades of events taking place at the implant surfaces upon immersion in the testing media or after implantation. Starting from an osteoinductive bioglass composition with the ability to alleviate the oxidative stress, thin bioglass films with different degrees of polymerization were deposited onto titanium substrates. Their biomineralization activity in simulated body fluid and in a series of new inorganic-organic media with increasing biomimicry that more closely simulated the human intercellular environment was compared. A comprehensive range of advanced characterization tools (scanning electron microscopy; grazing-incidence X-ray diffraction; Fourier-transform infrared, micro-Raman, energy-dispersive, X-ray photoelectron, and surface-enhanced laser desorption/ionization time-of-flight mass spectroscopies; and cytocompatibility assays using mesenchymal stem cells) were used. The information gathered is very useful to biologists, biophysicists, clinicians, and material scientists with special interest in teaching and research. By combining all the analyses, we propose herein a step forward toward establishing an improved unified protocol for testing the bioactivity of implant materials.

Polypropylene mesh augmentation for complete quadriceps rupture after total knee arthroplasty.

PubMed

Nodzo, Scott R; Rachala, Sridhar R

2016-01-01

Polypropylene mesh has previously been shown to be an effective treatment for failed patellar tendon repairs after total knee arthroplasty (TKA), but there have been few reports of this synthetic mesh used in complete quadriceps rupture after TKA. We retrospectively reviewed seven consecutive cases in six patients with complete quadriceps tears after TKA who had their quadriceps tendon repaired with suture and polypropylene mesh augmentation. All but two patients had previously failed primary suture repair. Patient outcomes were evaluated using the Knee Society Score. Standardized anterior-posterior (AP), lateral and merchant radiographs were evaluated preoperatively and at final follow-up. Seven knees in six patients were evaluated with a mean follow-up of 34±10 (range 24 to 49months) months. There were only four clinical successes defined as an extensor lag less than 30°. Of the functioning knees at final follow-up (n=5) the overall extensor lag in this group did significantly improve from 50±13° to 20±15° (range 5 to 40°) (p=.01). Mean postoperative flexion at final follow-up was 115±8°. Mean Knee Society Score for function improved from 20±30 to 45±54 (p=.03) as did the mean Knee Society Score for pain (44±18 vs. 74±78, p=.02). Polypropylene mesh offered limited postoperative functional results when used as an augment to the multiply operated knee that sustains a complete quadriceps rupture after TKA, but did allow for significant improvement in postoperative pain outcomes. IV. Copyright © 2015 Elsevier B.V. All rights reserved.

On the Stiffness of the Mesh and Urethral Mobility: A Finite Element Analysis.

PubMed

Brandão, Sofia; Parente, Marco; Da Roza, Thuane Huyer; Silva, Elisabete; Ramos, Isabel Maria; Mascarenhas, Teresa; Natal Jorge, Renato Manuel

2017-08-01

Midurethral slings are used to correct urethral hypermobility in female stress urinary incontinence (SUI), defined as the complaint of involuntary urine leakage when the intra-abdominal pressure (IAP) is increased. Structural and thermal features influence their mechanical properties, which may explain postoperative complications, e.g., erosion and urethral obstruction. We studied the effect of the mesh stiffness on urethral mobility at Valsalva maneuver, under impairment of the supporting structures (levator ani and/or ligaments), by using a numerical model. For that purpose, we modeled a sling with "lower" versus "higher" stiffness and evaluated the mobility of the bladder and urethra, that of the urethrovesical junction (the α-angle), and the force exerted at the fixation of the sling. The effect of impaired levator ani or pubourethral ligaments (PUL) alone on the organs displacement and α-angle opening was similar, showing their important role together on urethral stabilization. When the levator ani and all the ligaments were simulated as impaired, the descent of the bladder and urethra went up to 25.02 mm, that of the bladder neck was 14.57 mm, and the α-angle was 129.7 deg, in the range of what was found in women with SUI. Both meshes allowed returning to normal positioning, although at the cost of higher force exerted by the mesh with higher stiffness (3.4 N against 2.3 N), which can relate to tissue erosion. This finite element analysis allowed mimicking the biomechanical response of the pelvic structures in response to changing a material property of the midurethral synthetic mesh.

Photoactivated Composite Biomaterial for Soft Tissue Restoration in Rodents and in Humans

PubMed Central

Nahas, Zayna; Reid, Branden; Coburn, Jeannine M.; Axelman, Joyce; Chae, Jemin J.; Guo, Qiongyu; Trow, Robert; Thomas, Andrew; Hou, Zhipeng; Lichtsteiner, Serge; Sutton, Damon; Matheson, Christine; Walker, Patricia; David, Nathaniel; Mori, Susumu; Taube, Janis M.; Elisseeff, Jennifer H.

2015-01-01

Soft tissue reconstruction often requires multiple surgical procedures that can result in scars and disfiguration. Facial soft tissue reconstruction represents a clinical challenge because even subtle deformities can severely affect an individual’s social and psychological function. We therefore developed a biosynthetic soft tissue replacement composed of poly(ethylene glycol) (PEG) and hyaluronic acid (HA) that can be injected and photocrosslinked in situ with transdermal light exposure. Modulating the ratio of synthetic to biological polymer allowed us to tune implant elasticity and volume persistence. In a small-animal model, implanted photocrosslinked PEG-HA showed a dose-dependent relationship between increasing PEG concentration and enhanced implant volume persistence. In direct comparison with commercial HA injections, the PEG-HA implants maintained significantly greater average volumes and heights. Reversibility of the implant volume was achieved with hyaluronidase injection. Pilot clinical testing in human patients confirmed the feasibility of the transdermal photocrosslinking approach for implantation in abdomen soft tissue, although an inflammatory response was observed surrounding some of the materials. PMID:21795587

Computational mechanobiology to study the effect of surface geometry on peri-implant tissue differentiation.

PubMed

Andreykiv, A; van Keulen, F; Prendergast, P J

2008-10-01

The geometry of an implant surface to best promote osseointegration has been the subject of several experimental studies, with porous beads and woven mesh surfaces being among the options available. Furthermore, it is unlikely that one surface geometry is optimal for all loading conditions. In this paper, a computational method is used to simulate tissue differentiation and osseointegration on a smooth surface, a surface covered with sintered beads (this simulated the experiment (Simmons, C., and Pilliar, R., 2000, Biomechanical Study of Early Tissue Formation Around Bone-Interface Implants: The Effects of Implant Surface Geometry," Bone Engineering, J. E. Davies, ed., Emsquared, Chap. A, pp. 369-379) and established that the method gives realistic results) and a surface covered by porous tantalum. The computational method assumes differentiation of mesenchymal stem cells in response to fluid flow and shear strain and models cell migration and proliferation as continuum processes. The results of the simulation show a higher rate of bone ingrowth into the surfaces with porous coatings as compared with the smooth surface. It is also shown that a thicker interface does not increase the chance of fixation failure.

Options for Closure of the Infected Abdomen

PubMed Central

Campbell, Chris A.; Rosenberger, Laura H.; Politano, Amani D.; Davies, Stephen W.; Riccio, Lin M.; Sawyer, Robert G.

2012-01-01

Abstract Background The infected abdomen poses substantial challenges to surgeons, and often, both temporary and definitive closure techniques are required. We reviewed the options available to close the abdominal wall defect encountered frequently during and after the management of complicated intra-abdominal infections. Methods A comprehensive review was performed of the techniques and literature on abdominal closure in the setting of intra-abdominal infection. Results Temporary abdominal closure options include the Wittmann Patch, Bogota bag, vacuum-assisted closure (VAC), the AbThera™ device, and synthetic or biologic mesh. Definitive reconstruction has been described with mesh, components separation, and autologous tissue transfer. Conclusion Reconstructing the infected abdomen, both temporarily and definitively, can be accomplished with various techniques, each of which is associated with unique advantages and disadvantages. Appropriate judgment is required to optimize surgical outcomes in these complex cases. PMID:23216525

Convergence of regenerative medicine and synthetic biology to develop standardized and validated models of human diseases with clinical relevance.

PubMed

Hutmacher, Dietmar Werner; Holzapfel, Boris Michael; De-Juan-Pardo, Elena Maria; Pereira, Brooke Anne; Ellem, Stuart John; Loessner, Daniela; Risbridger, Gail Petuna

2015-12-01

In order to progress beyond currently available medical devices and implants, the concept of tissue engineering has moved into the centre of biomedical research worldwide. The aim of this approach is not to replace damaged tissue with an implant or device but rather to prompt the patient's own tissue to enact a regenerative response by using a tissue-engineered construct to assemble new functional and healthy tissue. More recently, it has been suggested that the combination of Synthetic Biology and translational tissue-engineering techniques could enhance the field of personalized medicine, not only from a regenerative medicine perspective, but also to provide frontier technologies for building and transforming the research landscape in the field of in vitro and in vivo disease models. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Tissue Engineering of Blood Vessels: Functional Requirements, Progress, and Future Challenges.

PubMed

Kumar, Vivek A; Brewster, Luke P; Caves, Jeffrey M; Chaikof, Elliot L

2011-09-01

Vascular disease results in the decreased utility and decreased availability of autologus vascular tissue for small diameter (< 6 mm) vessel replacements. While synthetic polymer alternatives to date have failed to meet the performance of autogenous conduits, tissue-engineered replacement vessels represent an ideal solution to this clinical problem. Ongoing progress requires combined approaches from biomaterials science, cell biology, and translational medicine to develop feasible solutions with the requisite mechanical support, a non-fouling surface for blood flow, and tissue regeneration. Over the past two decades interest in blood vessel tissue engineering has soared on a global scale, resulting in the first clinical implants of multiple technologies, steady progress with several other systems, and critical lessons-learned. This review will highlight the current inadequacies of autologus and synthetic grafts, the engineering requirements for implantation of tissue-engineered grafts, and the current status of tissue-engineered blood vessel research.

Effect of microstructure on the elasto-viscoplastic deformation of dual phase titanium structures

NASA Astrophysics Data System (ADS)

Ozturk, Tugce; Rollett, Anthony D.

2018-02-01

The present study is devoted to the creation of a process-structure-property database for dual phase titanium alloys, through a synthetic microstructure generation method and a mesh-free fast Fourier transform based micromechanical model that operates on a discretized image of the microstructure. A sensitivity analysis is performed as a precursor to determine the statistically representative volume element size for creating 3D synthetic microstructures based on additively manufactured Ti-6Al-4V characteristics, which are further modified to expand the database for features of interest, e.g., lath thickness. Sets of titanium hardening parameters are extracted from literature, and The relative effect of the chosen microstructural features is quantified through comparisons of average and local field distributions.

Full-color digitized holography for large-scale holographic 3D imaging of physical and nonphysical objects.

PubMed

Matsushima, Kyoji; Sonobe, Noriaki

2018-01-01

Digitized holography techniques are used to reconstruct three-dimensional (3D) images of physical objects using large-scale computer-generated holograms (CGHs). The object field is captured at three wavelengths over a wide area at high densities. Synthetic aperture techniques using single sensors are used for image capture in phase-shifting digital holography. The captured object field is incorporated into a virtual 3D scene that includes nonphysical objects, e.g., polygon-meshed CG models. The synthetic object field is optically reconstructed as a large-scale full-color CGH using red-green-blue color filters. The CGH has a wide full-parallax viewing zone and reconstructs a deep 3D scene with natural motion parallax.

Multidetector CT of expected findings and complications after contemporary inguinal hernia repair surgery

PubMed Central

Tonolini, Massimo

2016-01-01

Inguinal hernia repair (IHR) with prosthetic mesh implantation is the most common procedure in general surgery, and may be performed using either an open or laparoscopic approach. This paper provides an overview of contemporary tension-free IHR techniques and materials, and illustrates the expected postoperative imaging findings and iatrogenic injuries. Emphasis is placed on multidetector CT, which represents the ideal modality to comprehensively visualize the operated groin region and deeper intra-abdominal structures. CT consistently depicts seroma, mesh infections, hemorrhages, bowel complications and urinary bladder injuries, and thus generally provides a consistent basis for therapeutic choice. Since radiologists are increasingly requested to investigate suspected iatrogenic complications, this paper aims to provide an increased familiarity with early CT studies after IHR, including complications and normal postoperative appearances such as focal pseudolesions, in order to avoid misinterpretation and inappropriate management. PMID:27460285

Antibiotic prophylaxis in open inguinal hernia repair: a literature review and summary of current knowledge

PubMed Central

Makarewicz, Wojciech; Ropel, Jerzy; Bobowicz, Maciej; Kąkol, Michał; Śmietański, Maciej

2016-01-01

More than 1 million inguinal hernia repairs are performed in Europe and the US annually. Although antibiotic prophylaxis is not required in clean, elective procedures, the routine use of implants (90% of inguinal hernia repairs are performed with mesh) makes the topic controversial. The European Hernia Society does not recommend routine antibiotic prophylaxis for elective inguinal hernia repairs. However, the latest randomized controlled trial, published by Mazaki et al., indicates that the use of prophylaxis is effective for the prevention of surgical site infection. Unnecessary prophylaxis contributes to the development of bacterial resistance and significantly increases healthcare costs. This review documents clinical trials on inguinal hernia repairs with mesh and summarizes the current knowledge. It also tries to solve certain problems, namely: what constitutes a real risk factor, late-onset infection, and how the “surgical environment” impacts on the need to use antibiotic prophylaxis. PMID:27829934

Metal-oxide thin-film transistor-based pH sensor with a silver nanowire top gate electrode

NASA Astrophysics Data System (ADS)

Yoo, Tae-Hee; Sang, Byoung-In; Wang, Byung-Yong; Lim, Dae-Soon; Kang, Hyun Wook; Choi, Won Kook; Lee, Young Tack; Oh, Young-Jei; Hwang, Do Kyung

2016-04-01

Amorphous InGaZnO (IGZO) metal-oxide-semiconductor thin-film transistors (TFTs) are one of the most promising technologies to replace amorphous and polycrystalline Si TFTs. Recently, TFT-based sensing platforms have been gaining significant interests. Here, we report on IGZO transistor-based pH sensors in aqueous medium. In order to achieve stable operation in aqueous environment and enhance sensitivity, we used Al2O3 grown by using atomic layer deposition (ALD) and a porous Ag nanowire (NW) mesh as the top gate dielectric and electrode layers, respectively. Such devices with a Ag NW mesh at the top gate electrode rapidly respond to the pH of solutions by shifting the turn-on voltage. Furthermore, the output voltage signals induced by the voltage shifts can be directly extracted by implantation of a resistive load inverter.

The influence of implant-abutment connection to peri-implant bone loss: A systematic review and meta-analysis.

PubMed

Caricasulo, Riccardo; Malchiodi, Luciano; Ghensi, Paolo; Fantozzi, Giuliano; Cucchi, Alessandro

2018-05-15

Different implant-abutment connections are available and it has been claimed they could have an effect on marginal bone loss. The aim of this review is to establish if implant connection configuration influences peri-implant bone loss (PBL) after functional loading. A specific question was formulated according to the Population, Intervention, Control, and Outcome (PICO): Does the type of implant-abutment connection (external, internal, or conical) have an influence on peri-implant bone loss? A PubMed/MEDLINE electronic search was conducted to identify English language publications published in international journals during the last decade (from 2006 to 2016). The search was conducted by using the Medical Subject Headings (MeSH) keywords "dental implants OR dental abutment AND external connection OR internal connection OR conical connection OR Morse Taper." Selected studies were randomized clinical trials and prospective studies; in vitro studies, case reports and retrospective studies were excluded. Titles and abstracts and, in the second phase, full texts, were evaluated autonomously and in duplicate by two reviewers. A total of 1649 articles were found, but only 14 studies met the pre-established inclusion criteria and were considered suitable for meta-analytic analysis. The network meta-analysis (NMA) suggested a significant difference between the external and the conical connections; this was less evident for the internal and conical ones. Platform-switching (PS) seemed to positively affect bone levels, non-regarding the implant-connection it was applied to. Within the limitations of this systematic review, it can be concluded that crestal bone levels are better maintained in the short-medium term when internal kinds of interface are adopted. In particular, conical connections seem to be more advantageous, showing lower peri-implant bone loss, but further studies are necessary to investigate the efficacy of implant-abutment connection on stability of crestal bone levels. © 2018 Wiley Periodicals, Inc.

Stress analysis in platform-switching implants: a 3-dimensional finite element study.

PubMed

Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; Falcón-Antenucci, Rosse Mary; Júnior, Joel Ferreira Santiago; de Carvalho, Paulo Sérgio Perri; de Moraes, Sandra Lúcia Dantas; Noritomi, Pedro Yoshito

2012-10-01

The aim of this study was to evaluate the influence of the platform-switching technique on stress distribution in implant, abutment, and peri-implant tissues, through a 3-dimensional finite element study. Three 3-dimensional mandibular models were fabricated using the SolidWorks 2006 and InVesalius software. Each model was composed of a bone block with one implant 10 mm long and of different diameters (3.75 and 5.00 mm). The UCLA abutments also ranged in diameter from 5.00 mm to 4.1 mm. After obtaining the geometries, the models were transferred to the software FEMAP 10.0 for pre- and postprocessing of finite elements to generate the mesh, loading, and boundary conditions. A total load of 200 N was applied in axial (0°), oblique (45°), and lateral (90°) directions. The models were solved by the software NeiNastran 9.0 and transferred to the software FEMAP 10.0 to obtain the results that were visualized through von Mises and maximum principal stress maps. Model A (implants with 3.75 mm/abutment with 4.1 mm) exhibited the highest area of stress concentration with all loadings (axial, oblique, and lateral) for the implant and the abutment. All models presented the stress areas at the abutment level and at the implant/abutment interface. Models B (implant with 5.0 mm/abutment with 5.0 mm) and C (implant with 5.0 mm/abutment with 4.1 mm) presented minor areas of stress concentration and similar distribution pattern. For the cortical bone, low stress concentration was observed in the peri-implant region for models B and C in comparison to model A. The trabecular bone exhibited low stress that was well distributed in models B and C. Model A presented the highest stress concentration. Model B exhibited better stress distribution. There was no significant difference between the large-diameter implants (models B and C).

Sinus Floor Elevation and Augmentation Using Synthetic Nanocrystalline and Nanoporous Hydroxyapatite Bone Substitute Materials: Preliminary Histologic Results.

PubMed

Belouka, Sofia-Maria; Strietzel, Frank Peter

To compare the tissue composition of augmented sites after using two different synthetic bone substitute materials, nanocrystalline and nanoporous hydroxyapatite (HA), for sinus floor elevation and augmentation. Forty-four patients received 88 titanium screw implants (Camlog Promote plus) of 4.3-mm diameter and 11- or 13-mm length, placed simultaneously during sinus floor elevation and augmentation. Nanocrystalline (Ostim) or nanoporous (NanoBone) HA were used exclusively. Bone substitute materials and implant lengths were allocated by randomization. Bone biopsy specimens were obtained from the former area of the lateral access window at implant exposure during healing abutment placement after 6 months. Biopsy specimens were prepared and examined histologically and histomorphometrically. All implants were osseointegrated at the time of exposure. Clinically and histologically, no signs of inflammation in the augmented sites were present. The histomorphometric analysis of 44 biopsy specimens revealed 31.8% ± 11.6% newly formed bone for sites augmented with nanocrystalline HA and 34.6% ± 9.2% for nanoporous HA (P = .467). The proportion of remaining bone substitute material was 28.4% ± 18.6% and 30% ± 13%, respectively (P = .453). The proportion of soft tissue within the biopsy specimens was 39.9% ± 11.1% and 35.4% ± 6.8%, respectively (P = .064). No significant differences were found between the area fractions of bone, bone substitute material, and soft tissue concerning the bone substitute material utilized. Within the present study, both synthetic bone substitute materials, nanocrystalline and nanoporous HA, were found to support bone formation in sinus floor elevation and augmentation procedures by osteoconductivity. They were not completely resorbed after 6 months. The amounts of newly formed bone, soft tissue, and bone substitute material remnants were found to be similar, indicating that both materials are likewise suitable for sinus floor elevation and augmentation procedures.

Comparison of Lyophilized Glutaraldehyde-Preserved Bovine Pericardium with Different Vascular Prostheses for Use as Vocal Cords Implants: Experimental Study

PubMed Central

Olmos-Zuñiga, J. Raúl; Jasso-Victoria, Rogelio; Gaxiola-Gaxiola, Miguel; Sotres-Vega, Avelina; Hernández-Jiménez, Claudia; Baltazares-Lipp, Matilde; Arredondo del Bosque, Fernando; Santillan-Doherty, Patricio

2015-01-01

This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET. PMID:26075232

Comparison of lyophilized glutaraldehyde-preserved bovine pericardium with different vascular prostheses for use as vocal cords implants: experimental study.

PubMed

Olmos-Zuñiga, J Raúl; Jasso-Victoria, Rogelio; Gaxiola-Gaxiola, Miguel; Sotres-Vega, Avelina; Hernández-Jiménez, Claudia; Baltazares-Lipp, Matilde; Arredondo del Bosque, Fernando; Santillan-Doherty, Patricio

2015-01-01

This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET.

Resorbable fixation in facial plastic and head and neck reconstructive surgery: an initial report on polylactic acid implants.

PubMed

Moe, K S; Weisman, R A

2001-10-01

The purpose of this study was to evaluate and report our initial experience with a resorbable fixation system in facial cosmetic and head and neck reconstructive surgery. The specific goals were to determine in which settings the absorbable system could be used, to evaluate the outcome of its use, to detail complications that occurred, and to report our observations on advantages and disadvantages of the system compared with traditional methods of osteosynthesis and fixation. A retrospective review of the initial 30 consecutive patients at the University of California, San Diego Division of Head and Neck Surgery who received polylactic acid (PLA) implants. Academic tertiary referral/level I trauma center. Criteria for inclusion into the study were any patient over age 18 who underwent a procedure involving the use of a PLA implant between March 1999 and October 2000. In addition to the typical indications for metal plate or mesh implantation, PLA was used for "protected bone regeneration." Detailed records were kept of all patients in whom PLA implants were used, including the exact procedure and type of implant. All patients were operated by the authors. Operative reports, hospital charts, and office records were analyzed for any perioperative or postoperative complications. The attending surgeon noted advantages and disadvantages of the system. Patients have been followed from 2 to 18 months at the time of this report and are part of an ongoing long-term follow-up study. PLA implants were used in 35 procedures on 30 consecutive patients (multiple unilateral fracture repairs were counted as a single procedure). Uses included fixation of craniofacial fractures (zygomaticomaxillary, orbit floor, frontal bone [N = 9]; fixation of craniofacial osteotomy [N = 8]; protected bone regeneration [N = 3]; mandible, cranial bone donor site [N = 2]; bone grafting [N = 2]; craniectomy reconstruction [N = 2], and soft tissue suspension [endoscopic browlifting, N = 6, static facial suspension, N = 1]). There were 4 complications in this series: 2 partial flap losses, 1 in a patient who had had preoperative radiation and the other in a heavy smoker; 1 infected cranial bone flap in a patient who had had two prior surgeries and radiation; and 1 wound dehiscence over a plate that was improperly contoured. Advantages noted by the surgeons were ease of contouring the mesh or plates, including in situ reshaping, apparent decrease in operative time, low implant profile, minimal soft tissue reaction, and radiolucency of the system, allowing postoperative imaging without metallic artifact. We found the PLA system to be highly effective, and noted no absolute contraindications to its use compared with standard metal plating systems. The 11% incidence of complications in this series was acceptable and probably not the result of the PLA implant material, although further experience is needed to determine the role of PLA implants in radiated tissue. The primary advantages to PLA appear to be its ease of use, radiolucency, eventual resorption, and, possibly, improved precision of reduction. The use in protected bone regeneration may also be an advantage, but long-term follow-up of our population will be needed to determine this. Based on short-term outcome analysis of our initial experience with PLA implantation, it appears to be an efficacious and safe technology for applications in head and neck and facial plastic surgery.

Reduction of chronic post-herniotomy pain and recurrence rate. Use of the anatomical self-gripping ProGrip laparoscopic mesh in TAPP hernia repair. Preliminary results of a prospective study

PubMed Central

Hoskovec, David

2015-01-01

Introduction The role of fixation of the mesh is especially important in the endoscopic technique. The fixation of mesh through penetrating techniques using staples, clips or screws is associated with a significantly increased risk of developing a post-herniotomy pain syndrome. Aim To demonstrate the safety and efficacy of the self-fixating anatomical Parietex ProGrip laparoscopic mesh (Sofradim Production, Trévoux France) used with laparoscopic transabdominal preperitoneal hernia repair. The incidence of chronic post-herniotomy pain and recurrence rate in the follow-up after 12 months were evaluated. Material and methods Data analysis included all patients who underwent inguinal hernia surgery at our Surgical Department within the period from 1.05.2013 to 31.12.2014, who fulfilled the inclusion criteria. Standard surgical technique was used. Data were prospectively entered and subsequently analyzed on the Herniamed platform. Herniamed is an internet-based register in German and English language and includes all data of patients who underwent surgery for some types of hernia. Results There were 95 patients enrolled in the group and there were in total 156 inguinal hernias repaired. The mean follow-up was 15.52 months. At the assessment at 1 year mild discomfort in the groin was reported in 2 patients (3.51%) (1–3 VAS). No recurrence or chronic postoperative pain was reported. Conclusions Laparoscopic inguinal hernia repair using the transabdominal preperitoneal technique with implantation of the ProGrip laparoscopic mesh is a fast, effective and reliable method in experienced hands, which according to our results reduces the occurrence of chronic post-operative inguinal pain with simultaneously a low recurrence rate. PMID:26649083

[Design and biological evaluation of poly-lactic-co-glycolic acid (PLGA) mesh/collagen-chitosan hybrid scaffold (CCS) as a dermal substitute].

PubMed

Wang, Xin-Gang; You, Chuan-Gang; Sun, Hua-Feng; Hu, Xin-Lei; Han, Chun-Mao; Zhang, Li-Ping; Zheng, Yu-Rong; Li, Qi-Yin

2011-02-01

To design and construct a kind of dermal regeneration template with mesh, and to preliminarily evaluate its biological characteristics. PLGA mesh was integrated into CCS with freeze-drying method for constructing PLGA mesh/CCS composite (PCCS). The micromorphologies and mechanical properties among PLGA mesh, CCS, and PCCS were compared. PCCS and CCS was respectively implanted into subcutaneous tissue of SD rats (PCCS and CCS groups, 9 rats in each group). The tissue samples were collected at post operation week (POW) 1, 2, and 4 for histopathological and immunohistochemical observation. Protein levels of CD68, MPO, IL-1beta, IL-10 were examined by Western blot, with expression of gray value. Data were processed with one-way analysis of variance and t test. Three-dimensional porous structure of PCCS was similar to that of CCS. Mechanical property of PLGA mesh and PCCS was respectively (3.07 +/- 0.10), (3.26 +/- 0.15) MPa, and they were higher than that of CCS [(0.42 +/- 0.21) MPa, F = 592.3, P < 0.0001)]. The scaffolds were filled with newly formed tissue in PCCS group at POW 2, while those in CCS group were observed at POW 4. A large accumulation of macrophages was observed in both groups, especially at POW 2, and more macrophage infiltration was observed in CCS group. The protein level of IL-10 in PCCS group at POW 2 was obviously higher than that in CCS group, while the protein levels of CD68, MPO, IL-1beta were significantly decreased as compared with those in CCS group (with t value from -4.06 to 2.89, P < 0.05 or P < 0.01). PCCS has excellent mechanical property with appropriate three-dimensional porous structure. Meanwhile, it can rapidly induce formation of new tissue and vascularization, and it has a prospect of serving as a dermal substitute.

Octree-based Global Earthquake Simulations

NASA Astrophysics Data System (ADS)

Ramirez-Guzman, L.; Juarez, A.; Bielak, J.; Salazar Monroy, E. F.

2017-12-01

Seismological research has motivated recent efforts to construct more accurate three-dimensional (3D) velocity models of the Earth, perform global simulations of wave propagation to validate models, and also to study the interaction of seismic fields with 3D structures. However, traditional methods for seismogram computation at global scales are limited by computational resources, relying primarily on traditional methods such as normal mode summation or two-dimensional numerical methods. We present an octree-based mesh finite element implementation to perform global earthquake simulations with 3D models using topography and bathymetry with a staircase approximation, as modeled by the Carnegie Mellon Finite Element Toolchain Hercules (Tu et al., 2006). To verify the implementation, we compared the synthetic seismograms computed in a spherical earth against waveforms calculated using normal mode summation for the Preliminary Earth Model (PREM) for a point source representation of the 2014 Mw 7.3 Papanoa, Mexico earthquake. We considered a 3 km-thick ocean layer for stations with predominantly oceanic paths. Eigen frequencies and eigen functions were computed for toroidal, radial, and spherical oscillations in the first 20 branches. Simulations are valid at frequencies up to 0.05 Hz. Matching among the waveforms computed by both approaches, especially for long period surface waves, is excellent. Additionally, we modeled the Mw 9.0 Tohoku-Oki earthquake using the USGS finite fault inversion. Topography and bathymetry from ETOPO1 are included in a mesh with more than 3 billion elements; constrained by the computational resources available. We compared estimated velocity and GPS synthetics against observations at regional and teleseismic stations of the Global Seismological Network and discuss the differences among observations and synthetics, revealing that heterogeneity, particularly in the crust, needs to be considered.

A Monte Carlo investigation of lung brachytherapy treatment planning

NASA Astrophysics Data System (ADS)

Sutherland, J. G. H.; Furutani, K. M.; Thomson, R. M.

2013-07-01

Iodine-125 (125I) and Caesium-131 (131Cs) brachytherapy have been used in conjunction with sublobar resection to reduce the local recurrence of stage I non-small cell lung cancer compared with resection alone. Treatment planning for this procedure is typically performed using only a seed activity nomogram or look-up table to determine seed strand spacing for the implanted mesh. Since the post-implant seed geometry is difficult to predict, the nomogram is calculated using the TG-43 formalism for seeds in a planar geometry. In this work, the EGSnrc user-code BrachyDose is used to recalculate nomograms using a variety of tissue models for 125I and 131Cs seeds. Calculated prescription doses are compared to those calculated using TG-43. Additionally, patient CT and contour data are used to generate virtual implants to study the effects that post-implant deformation and patient-specific tissue heterogeneity have on perturbing nomogram-derived dose distributions. Differences of up to 25% in calculated prescription dose are found between TG-43 and Monte Carlo calculations with the TG-43 formalism underestimating prescription doses in general. Differences between the TG-43 formalism and Monte Carlo calculated prescription doses are greater for 125I than for 131Cs seeds. Dose distributions are found to change significantly based on implant deformation and tissues surrounding implants for patient-specific virtual implants. Results suggest that accounting for seed grid deformation and the effects of non-water media, at least approximately, are likely required to reliably predict dose distributions in lung brachytherapy patients.

Reversal of diabetes by pancreatic islet transplantation into a subcutaneous, neovascularized device.

PubMed

Pileggi, Antonello; Molano, R Damaris; Ricordi, Camillo; Zahr, Elsie; Collins, Jill; Valdes, Rafael; Inverardi, Luca

2006-05-15

Transplantation of pancreatic islets for the treatment of type 1 diabetes allows for physiologic glycemic control and insulin-independence when sufficient islets are implanted via the portal vein into the liver. Intrahepatic islet implantation requires specific infrastructure and expertise, and risks inherent to the procedure include bleeding, thrombosis, and elevation of portal pressure. Additionally, the relatively higher drug metabolite concentrations in the liver may contribute to the delayed loss of graft function of recent clinical trials. Identification of alternative implantation sites using biocompatible devices may be of assistance improving graft outcome. A desirable bioartificial pancreas should be easy to implant, biopsy, and retrieve, while allowing for sustained graft function. The subcutaneous (SC) site may require a minimally invasive procedure performed under local anesthesia, but its use has been hampered so far by lack of early vascularization, induction of local inflammation, and mechanical stress on the graft. Chemically diabetic rats received syngeneic islets into the liver or SC into a novel biocompatible device consisting of a cylindrical stainless-steel mesh. The device was implanted 40 days prior to islet transplantation to allow embedding by connective tissue and neovascularization. Reversal of diabetes and glycemic control was monitored after islet transplantation. Syngeneic islets transplanted into a SC, neovascularized device restored euglycemia and sustained function long-term. Removal of graft-bearing devices resulted in hyperglycemia. Explanted grafts showed preserved islets and intense vascular networks. Ease of implantation, biocompatibility, and ability to maintain long-term graft function support the potential of our implantable device for cellular-based reparative therapies.

Influence of parafunctional loading and prosthetic connection on stress distribution: a 3D finite element analysis.

PubMed

Torcato, Leonardo Bueno; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; Falcón-Antenucci, Rosse Mary; Santiago Júnior, Joel Ferreira; de Faria Almeida, Daniel Augusto

2015-11-01

Clinicians should consider parafunctional occlusal load when planning treatment. Prosthetic connections can reduce the stress distribution on an implant-supported prosthesis. The purpose of this 3-dimensional finite element study was to assess the influence of parafunctional loading and prosthetic connections on stress distribution. Computer-aided design software was used to construct 3 models. Each model was composed of a bone and an implant (external hexagon, internal hexagon, or Morse taper) with a crown. Finite element analysis software was used to generate the finite element mesh and establish the loading and boundary conditions. A normal force (200-N axial load and 100-N oblique load) and parafunctional force (1000-N axial and 500-N oblique load) were applied. Results were visualized as the maximum principal stress. Three-way analysis of variance and Tukey test were performed, and the percentage of contribution of each variable to the stress concentration was calculated from sum-of squares-analysis. Stress was concentrated around the implant at the cortical bone, and models with the external hexagonal implant showed the highest stresses (P<.001). Oblique loads produced high tensile stress concentrations on the site opposite the load direction. Internal connection implants presented the most favorable biomechanical situation, whereas the least favorable situation was the biomechanical behavior of external connection implants. Parafunctional loading increased the magnitude of stress by 3 to 4 times. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Dynamic and static strength of an implant-supported overdenture model reinforced with metal and nonmetal strengtheners.

PubMed

Rached, Rodrigo Nunes; de Souza, Evelise Machado; Dyer, Scott R; Ferracane, Jack Liborio

2011-11-01

Fractures of overdentures occur in the denture base through the abutments. The purpose of this study was to evaluate the effect of reinforcements and the space available for their placement on the dynamic and static loading capacity of a simulated implant-supported overdenture model. Rhomboidal (6 × 6 × 25 mm) test specimens (n=8), made with an acrylic resin and containing 2 metal O-ring capsules, were reinforced with braided stainless steel bar (BS), stainless steel mesh (SM), unidirectional E-glass fiber (GF), E-glass mesh (GM), woven polyethylene braids (PE), or polyaramid fibers (PA). Two distinct spaces for reinforcement placement were investigated: a 2.5 mm and a 1 mm space. Control groups consisted of nonreinforced specimens. Specimens were thermocycled (5°C and 55°C, 5,000 cycles) and then subjected to a 100,000 cyclic load regime. Unbroken specimens were then loaded until failure. The number of failures under fatigue (f) and static load (s) were compared with the Chi-Square test, while static load means were compared with the Kruskal-Wallis test (α=.05). The number of failures (f:s) of GF (0:16), PE (0:16), and PA (0:16) differed significantly from the control group (8:8) and SM (4:12) (P=.037 and P=.025, respectively). For the 2.5 mm space group, these same reinforcements also exhibited higher static load means than the control (P=.016, P=.003, and P=.003, respectively); under static load, no significant differences were detected between the reinforced groups and the control for the 1.0 mm space group (P=1.0). E-glass fibers, woven polyethylene braids, and polyaramid fibers withstood the fatigue regime and increased the flexural strength of the implant-supported overdenture model. The spaces available for reinforcement did not affect the dynamic strength or the static loading capacity of the implant-supported overdenture model. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Biomechanical changes of the lumbar segment after total disc replacement : charite(r), prodisc(r) and maverick(r) using finite element model study.

PubMed

Kim, Ki-Tack; Lee, Sang-Hun; Suk, Kyung-Soo; Lee, Jung-Hee; Jeong, Bi-O

2010-06-01

The purpose of this study was to analyze the biomechanical effects of three different constrained types of an artificial disc on the implanted and adjacent segments in the lumbar spine using a finite element model (FEM). The created intact model was validated by comparing the flexion-extension response without pre-load with the corresponding results obtained from the published experimental studies. The validated intact lumbar model was tested after implantation of three artificial discs at L4-5. Each implanted model was subjected to a combination of 400 N follower load and 5 Nm of flexion/extension moments. ABAQUS version 6.5 (ABAQUS Inc., Providence, RI, USA) and FEMAP version 8.20 (Electronic Data Systems Corp., Plano, TX, USA) were used for meshing and analysis of geometry of the intact and implanted models. Under the flexion load, the intersegmental rotation angles of all the implanted models were similar to that of the intact model, but under the extension load, the values were greater than that of the intact model. The facet contact loads of three implanted models were greater than the loads observed with the intact model. Under the flexion load, three types of the implanted model at the L4-5 level showed the intersegmental rotation angle similar to the one measured with the intact model. Under the extension load, all of the artificial disc implanted models demonstrated an increased extension rotational angle at the operated level (L4-5), resulting in an increase under the facet contact load when compared with the adjacent segments. The increased facet load may lead to facet degeneration.

Proximal Femoral Reconstructions with Bone Impaction Grafting and Metal Mesh

PubMed Central

Comba, Fernando; Piccaluga, Francisco

2009-01-01

Extensive circumferential proximal cortical bone loss is considered by some a contraindication for impaction bone grafting in the femur. We asked whether reconstruction with a circumferential metal mesh, impacted bone allografts, and a cemented stem would lead to acceptable survival in these patients. We retrospectively reviewed 14 patients (15 hips) with severe proximal femoral bone defects (average, 12 cm long; 14 type IV and one type IIIB using the classification of Della Valle and Paprosky) reconstructed with this method. The minimum followup was 20 months (average, 43.2 months; range, 20–72 months). Preoperative Merle D’Aubigné and Postel score averaged 4.8 points. With revision of the stem as the end point, the survivorship of the implant was 100% at one year and 86.6% at 72 months. The mean functional score at last followup was 14.4 points. We observed two fractures of the metal mesh at 31 and 48 months in cases reconstructed with a stem that did not bypass the mesh. Dislocation (3 cases) and acute deep infection (3 cases) were the most frequent complications. Patients with complete absence of the proximal femur may be candidates for biological proximal femoral reconstructions using this salvage procedure. Bone impaction grafting must be a routine technique if this method is selected. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:19294476

Quantitative Analysis of Electro-Anatomical Maps: Application to an Experimental Model of Left Bundle Branch Block/Cardiac Resynchronization Therapy

PubMed Central

Duchateau, Nicolas; Kostantyn Butakov, Constantine Butakoff; Andreu, David; Fernández-Armenta, Juan; Bijnens, Bart; Berruezo, Antonio; Sitges, Marta; Camara, Oscar

2017-01-01

Electro-anatomical maps (EAMs) are commonly acquired in clinical routine for guiding ablation therapies. They provide voltage and activation time information on a 3-D anatomical mesh representation, making them useful for analyzing the electrical activation patterns in specific pathologies. However, the variability between the different acquisitions and anatomies hampers the comparison between different maps. This paper presents two contributions for the analysis of electrical patterns in EAM data from biventricular surfaces of cardiac chambers. The first contribution is an integrated automatic 2-D disk representation (2-D bull’s eye plot) of the left ventricle (LV) and right ventricle (RV) obtained with a quasi-conformal mapping from the 3-D EAM meshes, that allows an analysis of cardiac resynchronization therapy (CRT) lead positioning, interpretation of global (total activation time), and local indices (local activation time (LAT), surrogates of conduction velocity, inter-ventricular, and transmural delays) that characterize changes in the electrical activation pattern. The second contribution is a set of indices derived from the electrical activation: speed maps, computed from LAT values, to study the electrical wave propagation, and histograms of isochrones to analyze regional electrical heterogeneities in the ventricles. We have applied the proposed methods to look for the underlying physiological mechanisms of left bundle branch block (LBBB) and CRT, with the goal of optimizing the therapy by improving CRT response. To better illustrate the benefits of the proposed tools, we created a set of synthetically generated and fully controlled activation patterns, where the proposed representation and indices were validated. Then, the proposed analysis tools are used to analyze EAM data from an experimental swine model of induced LBBB with an implanted CRT device. We have analyzed and compared the electrical activation patterns at baseline, LBBB, and CRT stages in four animals: two without any structural disease and two with an induced infarction. By relating the CRT lead location with electrical dyssynchrony, we evaluated current hypotheses about lead placement in CRT and showed that optimal pacing sites should target the RV lead close to the apex and the LV one distant from it. PMID:29164019

Insights from Synthetic Star-forming Regions. I. Reliable Mock Observations from SPH Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koepferl, Christine M.; Robitaille, Thomas P.; Biscani, Francesco

Through synthetic observations of a hydrodynamical simulation of an evolving star-forming region, we assess how the choice of observational techniques affects the measurements of properties that trace star formation. Testing and calibrating observational measurements requires synthetic observations that are as realistic as possible. In this part of the series (Paper I), we explore different techniques for mapping the distributions of densities and temperatures from the particle-based simulations onto a Voronoi mesh suitable for radiative transfer and consequently explore their accuracy. We further test different ways to set up the radiative transfer in order to produce realistic synthetic observations. We give amore » detailed description of all methods and ultimately recommend techniques. We have found that the flux around 20 μ m is strongly overestimated when blindly coupling the dust radiative transfer temperature with the hydrodynamical gas temperature. We find that when instead assuming a constant background dust temperature in addition to the radiative transfer heating, the recovered flux is consistent with actual observations. We present around 5800 realistic synthetic observations for Spitzer and Herschel bands, at different evolutionary time-steps, distances, and orientations. In the upcoming papers of this series (Papers II, III, and IV), we will test and calibrate measurements of the star formation rate, gas mass, and the star formation efficiency using our realistic synthetic observations.« less

Self-expanding stent made of polyester mesh with silicon coating (Polyflex) in the treatment of inoperable tracheal stenoses.

PubMed

Terra, Ricardo Mingarini; Minamoto, Helio; Tedde, Miguel Lia; Almeida, José Luiz Jesus de; Jatene, Fabio Biscegli

2007-01-01

To evaluate the Polyflex stent in terms of its efficacy, ease of implantation, and complications in patients with tracheobronchial affections. This was a prospective study, in which sixteen patients with inoperable tracheal stenosis secondary to orotracheal intubation (n = 12), neoplasia (n = 3), or Wegener's granulomatosis (n = 1) were monitored. Of these patients, eleven were women, and five were men. The mean age was 42.8 years (range, 21-72 years). Patients were submitted to implantation of a total of 21 Polyflex stents. All procedures were carried out in the operating room under general anesthesia, and the stents were implanted via suspension laryngoscopy using the stent applicator. Stents were implanted and symptoms were resolved in all cases. The stents remained in place for a mean period of 7.45 months, ranging from 2 to 18 months. The complications observed in the immediate postoperative period were dysphonia (in two patients, 12.5%) and odynophagia (in two patients, 12.5%). Late complications were cough (in ten patients, 62.5%), migration (in seven patients, 43.75%), granuloma formation (in two patients, 12.5%), and pneumonia (in one patient, 6.25%). The Polyflex stent is easily implanted, easily removed, well tolerated by patients and effective in resolving symptoms. However, its use is associated with a high rate of migration, especially in patients with post-orotracheal intubation stenosis.

The influence of BMI, smoking, and age on vaginal erosions after synthetic mesh repair of pelvic organ prolapses. A multicenter study.

PubMed

Araco, Francesco; Gravante, Gianpiero; Sorge, Roberto; Overton, John; De Vita, Davide; Primicerio, Mario; Dati, Stefano; Araco, Placido; Piccione, Emilio

2009-01-01

To study the influence of body mass index (BMI), smoking, and age on the risk of vaginal erosions after mesh repair of pelvic prolapses. Retrospective study. Three university and community hospitals. Patients that underwent mesh correction of prolapses between 2002 and 2007. Excluded were those with stress urinary incontinence, ongoing clinical infections, with a complete antibiotic course in the last six months and with systemic diseases affecting tissue oxygenation. Revision of medical notes. Risk contributions for age, smoking, and BMI on the occurrence of vaginal erosions. Data were collected from 460 patients. Postoperative erosions were present in 7%. BMI greater than 30 conferred a 10.1-fold increase in the risk of developing erosions, smoking a 3.7-fold increase, and age greater than 60 years a 2.2-fold increase. A cut-off value of seven pack years was determined for smoking where the risk associated with light smokers was similar to that of non-smokers. BMI, smoking, and age are important risk factors for pelvic organ prolapse surgery. Our data could be used to stratify patients according to their risk so that preventative measures can be taken in high-risk patients.

Progress in Computational Simulation of Earthquakes

NASA Technical Reports Server (NTRS)

Donnellan, Andrea; Parker, Jay; Lyzenga, Gregory; Judd, Michele; Li, P. Peggy; Norton, Charles; Tisdale, Edwin; Granat, Robert

2006-01-01

GeoFEST(P) is a computer program written for use in the QuakeSim project, which is devoted to development and improvement of means of computational simulation of earthquakes. GeoFEST(P) models interacting earthquake fault systems from the fault-nucleation to the tectonic scale. The development of GeoFEST( P) has involved coupling of two programs: GeoFEST and the Pyramid Adaptive Mesh Refinement Library. GeoFEST is a message-passing-interface-parallel code that utilizes a finite-element technique to simulate evolution of stress, fault slip, and plastic/elastic deformation in realistic materials like those of faulted regions of the crust of the Earth. The products of such simulations are synthetic observable time-dependent surface deformations on time scales from days to decades. Pyramid Adaptive Mesh Refinement Library is a software library that facilitates the generation of computational meshes for solving physical problems. In an application of GeoFEST(P), a computational grid can be dynamically adapted as stress grows on a fault. Simulations on workstations using a few tens of thousands of stress and displacement finite elements can now be expanded to multiple millions of elements with greater than 98-percent scaled efficiency on over many hundreds of parallel processors (see figure).

Design and mechanical behavior of the MD series of bone dowels

NASA Astrophysics Data System (ADS)

Bianchi, John R.

Allograft bone dowels, developed at the University of Florida Tissue Bank, Inc (UFTB) and Regeneration Technologies, Inc (RTI), offer an alternative to the more conventional metallic and other synthetic dowels for spinal fusions. These dowels are machined from the long bone of human donor tissue. They are an advance over current implants because they possess the precise dimensional characteristics that are typical of metallic or other synthetic implants, are composed of mostly cortical bone, do not cause additional donor site morbidity associated with autografts, yet they retain the advantageous osteogenic characteristics of allografts and autografts. Allograft and autograft tissues have a well-established history in spinal fusions. However, postoperative failures are commonly reported. These failures are due to the variations in geometric, material, and mechanical properties of the implants. In addition, little research effort has been placed on insuring that these types of implants have at least a minimum level of load bearing capacity. The results of this research developed a novel method, based on statistical procedures and fracture mechanisms, that defines the strength of the MD-series of bone dowels and uses this technique to establish a nondestructive mechanical quality control procedure. In addition, the influence of donor characteristics such as age, and sex on the strength of the dowels was established. The role of different tissue banking processing steps on the strength of machined tissue was identified, as well as differences in strength among different dowel designs determined.

Dynamic Rupture Modeling in Three Dimensions on Unstructured Meshes Using a Discontinuous Galerkin Method

NASA Astrophysics Data System (ADS)

Pelties, C.; Käser, M.

2010-12-01

We will present recent developments concerning the extensions of the ADER-DG method to solve three dimensional dynamic rupture problems on unstructured tetrahedral meshes. The simulation of earthquake rupture dynamics and seismic wave propagation using a discontinuous Galerkin (DG) method in 2D was recently presented by J. de la Puente et al. (2009). A considerable feature of this study regarding spontaneous rupture problems was the combination of the DG scheme and a time integration method using Arbitrarily high-order DERivatives (ADER) to provide high accuracy in space and time with the discretization on unstructured meshes. In the resulting discrete velocity-stress formulation of the elastic wave equations variables are naturally discontinuous at the interfaces between elements. The so-called Riemann problem can then be solved to obtain well defined values of the variables at the discontinuity itself. This is in particular valid for the fault at which a certain friction law has to be evaluated. Hence, the fault’s geometry is honored by the computational mesh. This way, complex fault planes can be modeled adequately with small elements while fast mesh coarsening is possible with increasing distance from the fault. Due to the strict locality of the scheme using only direct neighbor communication, excellent parallel behavior can be observed. A further advantage of the scheme is that it avoids spurious high-frequency contributions in the slip rate spectra and therefore does not require artificial Kelvin-Voigt damping or filtering of synthetic seismograms. In order to test the accuracy of the ADER-DG method the Southern California Earthquake Center (SCEC) benchmark for spontaneous rupture simulations was employed. Reference: J. de la Puente, J.-P. Ampuero, and M. Käser (2009), Dynamic rupture modeling on unstructured meshes using a discontinuous Galerkin method, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, B10302, doi:10.1029/2008JB006271

Holmium:YAG Laser Ablation for the Management of Lower Urinary Tract Foreign Bodies Following Incontinence Surgery: A Case Series and Systematic Review.

PubMed

Chan, Garson; Mamut, Adiel; Martin, Paul; Welk, Blayne

2016-11-01

The objective of this study was to determine the outcomes associated with the endoscopic removal of foreign bodies (such as mesh or permanent suture) in the lower urinary tract after female stress incontinence surgery with the Holmium:YAG (Ho:YAG) laser, and to systematically review the literature on this topic. A retrospective chart review of 18 consecutive women found to have mesh or suture exposure was performed. All patients underwent Ho:YAG laser ablation. A systematic review was performed to identify literature addressing the endoscopic management of mesh/suture exposure after stress incontinence surgery. Between November 2011 and February 2016, 18 women underwent Ho:YAG laser ablation of exposed mesh or suture. Presenting symptoms included lower urinary tract symptoms, pelvic pain, incontinence, or recurrent urinary tract infections. Thirteen women had a previous synthetic midurethral sling and five had a prior retropubic suspension. The median age was 58 years (interquartile range [IQR] 50-60) and median follow-up was 2 years (IQR 1-2). Four patients (22%) had residual mesh after the first procedure, requiring a repeat endoscopic procedure. Only one patient had a small amount of asymptomatic residual mesh on cystoscopy after the final procedure. Only minor postoperative complications were observed. Eight patients had stress incontinence and four underwent operative treatment for this. In our systematic review, we identified 16 case series, which described a total of 158 patients. Women most commonly presented with voiding symptoms or incontinence. Based on the synthesis of these data, repeat procedures were necessary in 16% and vesicovaginal fistula occurred in 2%. Recurrent/persistent stress incontinence was present in 20%, and of these patients, 3/4 underwent a new stress incontinence procedure. Both our case series and the systematic review of the literature demonstrated that endoscopic treatment of lower urinary tract foreign bodies after stress incontinence surgery has good success rates and minimal morbidity.

Bovine versus porcine acellular dermal matrix for complex abdominal wall reconstruction.

PubMed

Clemens, Mark W; Selber, Jesse C; Liu, Jun; Adelman, David M; Baumann, Donald P; Garvey, Patrick B; Butler, Charles E

2013-01-01

Abdominal wall reconstruction with bioprosthetic mesh is associated with lower rates of mesh infection, fistula formation, and mesh explantation than reconstruction with synthetic mesh. The authors directly compared commonly used bioprosthetic meshes in terms of clinical outcomes and complications. A database of consecutive patients who underwent abdominal wall reconstruction with porcine or bovine acellular dermal matrix and midline musculofascial closure at their institution between January of 2008 and March of 2011 was reviewed. Surgical outcomes were compared. One hundred twenty patients were identified who underwent a nonbridged, inlay abdominal wall reconstruction with porcine [69 patients (57.5 percent)] or bovine acellular dermal matrix (51 patients (42.5 percent)]. The mean follow-up time was 21.0 ± 9.9 months. The overall complication rate was 36.6 percent; the porcine matrix group had a significantly higher complication rate (44.9 percent) than the bovine matrix group (25.5 percent; p = 0.04) and statistically equivalent surgical complications (29.2 percent versus 21.6 percent; p = 0.34). There were no significant differences in rates of recurrent hernia (2.9 percent versus 3.9 percent; p = 0.99) or bulge (7.2 percent versus 0 percent; p = 0.07). However, the rate of intraoperative adverse events in the porcine matrix group [seven events (10.1 percent)] was significantly higher than that in the bovine matrix group (0 percent; p = 0.02). In patients who undergo complex abdominal wall reconstruction, both bovine and porcine acellular dermal matrix are associated with similar rates of postoperative surgical complications and appear to result in similar outcomes. Porcine acellular dermal matrix may be prone to intraoperative device failure. Therapeutic, III.

[Vaginal mesh operations in the urogynecological practice after the FDA warnings. Use or not to use mesh?

PubMed

Fekete, Zoltán; Körösi, Szilvia; Németh, Gábor

2018-03-01

The prevalence of pelvic organ prolapse (POP) with aging is escalating alarmingly, and now becoming a growing epidemic among the elderly. Synthetic transvaginal mesh (TVM) has been employed with increasing popularity in the treatment of POP until the end of the last decade. After the U.S. Drug and Food Administration (FDA) warnings in the years 2008 and 2011, the number of vaginal mesh operations has decreased dramatically. The aim of the study was to evaluate and compare the anti-POP effectivity, the anti-stress incontinence (anti-SUI) efficacy, and the late (36 months) post-operative complications of the anterior vaginoplasty and the TVM operations. We analysed the clinical data from 120 patients with stage II-III anterior prolapse and concomitant SUI who had undergone surgery at a tertiary referral centre in Hungary between January 2013 and January 2014. Sixty patients underwent Kelly-Stoeckel vaginoplasty and the other 60 cases had TVM operation. The surgical complications were classified using the Clavien-Dindo (CD) classification system. The anti-POP (91.6% vs. 63.3%; p<0.001) and the anti-SUI efficacy (90% vs. 55%, p<0.001) were significantly higher in the TVM group than in the vaginoplasty group, while the overall extrusion rate was found 8.3% after a 3-year follow-up. The Clavien-Dindo score (CD) proved that the early post-operative complication profile was similar among the TVM patients as compared to the vaginoplasty group (p = 0.405). Vaginal mesh surgery represents an effective procedure for prolapse and concomitant SUI with a decreased risk of short- and long-term complications. Orv Hetil. 2018; 159(10): 397-404.

Electrochemical surface modification of carbon mesh anode to improve the performance of air-cathode microbial fuel cells.

PubMed

Luo, Jianmei; Chi, Meiling; Wang, Hongyu; He, Huanhuan; Zhou, Minghua

2013-12-01

A convenient and promising alternative to surface modification of carbon mesh anode was fulfilled by electrochemical oxidation in the electrolyte of nitric acid or ammonium nitrate at ambient temperature. It was confirmed that such an anode modification method was low cost and effective not only in improving the efficiency of power generation in microbial fuel cells (MFCs) for synthetic wastewater treatment, but also helping to reduce the period for MFCs start-up. The MFCs with anode modification in electrolyte of nitric acid performed the best, achieving a Coulombic efficiency enhancement of 71 %. As characterized, the electrochemical modification resulted in the decrease of the anode potential and internal resistance but the increase of current response and nitrogen-containing and oxygen-containing functional groups on the carbon surface, which might contribute to the enhancement on the performances of MFCs.

The use of synthetic ligaments in the design of an enhanced stability total knee joint replacement.

PubMed

Stokes, Michael D; Greene, Brendan C; Pietrykowski, Luke W; Gambon, Taylor M; Bales, Caroline E; DesJardins, John D

2018-03-01

Current total knee replacement designs work to address clinically desired knee stability and range of motion through a balance of retained anatomy and added implant geometry. However, simplified implant geometries such as bearing surfaces, posts, and cams are often used to replace complex ligamentous constraints that are sacrificed during most total knee replacement procedures. This article evaluates a novel total knee replacement design that incorporates synthetic ligaments to enhance the stability of the total knee replacement system. It was hypothesized that by incorporating artificial cruciate ligaments into a total knee replacement design at specific locations and lengths, the stability of the total knee replacement could be significantly altered while maintaining active ranges of motion. The ligament attachment mechanisms used in the design were evaluated using a tensile test, and determined to have a safety factor of three with respect to expected ligamentous loading in vivo. Following initial computational modeling of possible ligament orientations, a physical prototype was constructed to verify the function of the design by performing anterior/posterior drawer tests under physiologic load. Synthetic ligament configurations were found to increase total knee replacement stability up to 94% compared to the no-ligament case, while maintaining total knee replacement flexion range of motion between 0° and 120°, indicating that a total knee replacement that incorporates synthetic ligaments with calibrated location and lengths should be able to significantly enhance and control the kinematic performance of a total knee replacement system.

Tissue engineering for lateral ridge augmentation with recombinant human bone morphogenetic protein 2 combination therapy: a case report.

PubMed

Mandelaris, George A; Spagnoli, Daniel B; Rosenfeld, Alan L; McKee, James; Lu, Mei

2015-01-01

This case report describes a tissue-engineered reconstruction with recombinant human bone morphogenetic protein 2/acellular collagen sponge (rhBMP-2/ ACS) + cancellous allograft and space maintenance via Medpor Contain mesh in the treatment of a patient requiring maxillary and mandibular horizontal ridge augmentation to enable implant placement. The patient underwent a previously unsuccessful corticocancellous bone graft at these sites. Multiple and contiguous sites in the maxilla and in the mandibular anterior, demonstrating advanced lateral ridge deficiencies, were managed using a tissue engineering approach as an alternative to autogenous bone harvesting. Four maxillary and three mandibular implants were placed 9 and 10 months, respectively, after tissue engineering reconstruction, and all were functioning successfully after 24 months of follow-up. Histomorphometric analysis of a bone core obtained at the time of the maxillary implant placement demonstrated a mean of 76.1% new vital bone formation, 22.2% marrow/cells, and 1.7% residual graft tissue. Tissue engineering for lateral ridge augmentation with combination therapy requires further research to determine predictability and limitations.

Nanotechnology Approaches for Better Dental Implants

PubMed Central

Tomsia, Antoni P.; Launey, Maximilien E.; Lee, Janice S.; Mankani, Mahesh H.; Wegst, Ulrike G.K.; Saiz, Eduardo

2011-01-01

The combined requirements imposed by the enormous scale and overall complexity of designing new implants or complete organ regeneration are well beyond the reach of present technology in many dimensions, including nanoscale, as we do not yet have the basic knowledge required to achieve these goals. The need for a synthetic implant to address multiple physical and biological factors imposes tremendous constraints on the choice of suitable materials. There is a strong belief that nanoscale materials will produce a new generation of implant materials with high efficiency, low cost, and high volume. The nanoscale in materials processing is truly a new frontier. Metallic dental implants have been successfully used for decades but they have serious shortcomings related to their osseointegration and the fact that their mechanical properties do not match those of bone. This paper reviews recent advances in the fabrication of novel coatings and nanopatterning of dental implants. It also provides a general summary of the state of the art in dental implant science and describes possible advantages of nanotechnology for further improvements. The ultimate goal is to produce materials and therapies that will bring state-of-the-art technology to the bedside and improve quality of life and current standards of care. PMID:21464998

Calculation of grain boundary normals directly from 3D microstructure images

DOE PAGES

Lieberman, E. J.; Rollett, A. D.; Lebensohn, R. A.; ...

2015-03-11

The determination of grain boundary normals is an integral part of the characterization of grain boundaries in polycrystalline materials. These normal vectors are difficult to quantify due to the discretized nature of available microstructure characterization techniques. The most common method to determine grain boundary normals is by generating a surface mesh from an image of the microstructure, but this process can be slow, and is subject to smoothing issues. A new technique is proposed, utilizing first order Cartesian moments of binary indicator functions, to determine grain boundary normals directly from a voxelized microstructure image. In order to validate the accuracymore » of this technique, the surface normals obtained by the proposed method are compared to those generated by a surface meshing algorithm. Specifically, the local divergence between the surface normals obtained by different variants of the proposed technique and those generated from a surface mesh of a synthetic microstructure constructed using a marching cubes algorithm followed by Laplacian smoothing is quantified. Next, surface normals obtained with the proposed method from a measured 3D microstructure image of a Ni polycrystal are used to generate grain boundary character distributions (GBCD) for Σ3 and Σ9 boundaries, and compared to the GBCD generated using a surface mesh obtained from the same image. Finally, the results show that the proposed technique is an efficient and accurate method to determine voxelized fields of grain boundary normals.« less

Healing potential of transplanted allogeneic chondrocytes of three different sources in lesions of the avascular zone of the meniscus: a pilot study.

PubMed

Weinand, Christian; Peretti, Giuseppe M; Adams, Samuel B; Randolph, Mark A; Savvidis, Estafios; Gill, Thomas J

2006-11-01

Successful treatment of tears to the avascular region of the meniscus remains a challenge. Current repair techniques, such as sutures and anchors, are effective in stabilizing the peripheral, vascularized regions of the meniscus, but are not adequate for promoting healing in the avascular region. The purpose of this study was to demonstrate the healing ability of a tissue-engineered repair technique using allogenic chondrocytes from three different sources for the avascular zone of the meniscus. Articular, auricular, and costal chondrocytes were harvested from 3-month-old Yorkshire swine. A 1-cm bucket-handle lesion was created in the avascular zone of each three swine. A cell-scaffold construct, composed of a single chondrocyte cell type and Vicryl mesh, was implanted into the lesion and secured with two vertical mattress sutures. Controls consisted of each three sutured unseeded mesh implants, suture only, and untreated lesions. The swine were allowed immediate post-operative full weight bearing. Menisci and controls were harvested after 12 weeks. In all experimental samples, lesion closure was observed. Gross mechanical testing with two Adson forceps demonstrated bonding of the lesion. Histological analysis showed formation of new tissue in all three experimental samples. None of the control samples demonstrated closure and formation of new matrix. We present preliminary data that demonstrates the potential of a tissue-engineered, allogenic cellular repair to provide successful healing of lesions in the avascular zone in a large animal model.

Short uncemented stems allow greater femoral flexibility and may reduce peri-prosthetic fracture risk: a dry bone and cadaveric study.

PubMed

Jones, Christopher; Aqil, Adeel; Clarke, Susannah; Cobb, Justin P

2015-09-01

Short femoral stems for uncemented total hip arthroplasty have been introduced as a safe alternative to traditional longer stem designs. However, there has been little biomechanical examination of the effects of stem length on complications of surgery. This study aims to examine the effect of femoral stem length on torsional resistance to peri-prosthetic fracture. We tested 16 synthetic and two paired cadaveric femora. Specimens were implanted and then rapidly rotated until fracture to simulate internal rotation on a planted foot, as might occur during stumbling. 3D planning software and custom-printed 3D cutting guides were used to enhance the accuracy and consistency of our stem insertion technique. Synthetic femora implanted with short stems fractured at a significantly higher torque (27.1 vs. 24.2 Nm, p = 0.03) and angle (30.3° vs. 22.3°, p = 0.002) than those implanted with long stems. Fracture patterns of the two groups were different, but showed remarkable consistency within each group. These characteristic fracture patterns were closely replicated in the pair of cadaveric femora. This new short-stemmed press-fit femoral component allows more femoral flexibility and confers a higher resistance to peri-prosthetic fracture from torsional forces than long stems.

[Current issues, problems and prospects of tension-free hernioplasty (review)].

PubMed

2014-01-01

In the present study there are discussed modern methods of the tension free hernioplastics, the complications associated with them and technical difficulties, up-to-date views and the perspectives of the issue development in terms of avoiding infectious complications, positioning of implants and their fixation. Hernia is one of the widespread surgical pathologies as it is found in 4% of the population and its share among the inpatient surgical diseases is about 18-30%. Consequently annually up to 20-21 mln hernioplasties are carried out worldwide. Despite of many years of experience in the field of hernia surgical treatment there still exist many unsolved problems such as safe closure of defects of abdominal cavity wall. Up to 200 methods of hernioplastics, various implantations and application of synthetic materials refer to lack of the optimal surgical strategy. In modern herniology priorities are given to tension free plastics. The merge of the synthetic implants and "tension free hernioplastics" concepts enabled sharp reduction of the side effects list, making it possible to perform successful surgeries in that contingent whose treatment by the method of tissue-plasty was related with high risk of lethality. Large scale introduction of tension free hernioplastics caused intensification of the associated problems such as migration, dissection and shortening of the net.

Decellularized Diaphragmatic Muscle Drives a Constructive Angiogenic Response In Vivo.

PubMed

Alvarèz Fallas, Mario Enrique; Piccoli, Martina; Franzin, Chiara; Sgrò, Alberto; Dedja, Arben; Urbani, Luca; Bertin, Enrica; Trevisan, Caterina; Gamba, Piergiorgio; Burns, Alan J; De Coppi, Paolo; Pozzobon, Michela

2018-04-28

Skeletal muscle tissue engineering (TE) aims to efficiently repair large congenital and acquired defects. Biological acellular scaffolds are considered a good tool for TE, as decellularization allows structural preservation of tissue extracellular matrix (ECM) and conservation of its unique cytokine reservoir and the ability to support angiogenesis, cell viability, and proliferation. This represents a major advantage compared to synthetic scaffolds, which can acquire these features only after modification and show limited biocompatibility. In this work, we describe the ability of a skeletal muscle acellular scaffold to promote vascularization both ex vivo and in vivo. Specifically, chicken chorioallantoic membrane assay and protein array confirmed the presence of pro-angiogenic molecules in the decellularized tissue such as HGF, VEGF, and SDF-1α. The acellular muscle was implanted in BL6/J mice both subcutaneously and ortotopically. In the first condition, the ECM-derived scaffold appeared vascularized 7 days post-implantation. When the decellularized diaphragm was ortotopically applied, newly formed blood vessels containing CD31⁺, αSMA⁺, and vWF⁺ cells were visible inside the scaffold. Systemic injection of Evans Blue proved function and perfusion of the new vessels, underlying a tissue-regenerative activation. On the contrary, the implantation of a synthetic matrix made of polytetrafluoroethylene used as control was only surrounded by vWF⁺ cells, with no cell migration inside the scaffold and clear foreign body reaction (giant cells were visible). The molecular profile and the analysis of macrophages confirmed the tendency of the synthetic scaffold to enhance inflammation instead of regeneration. In conclusion, we identified the angiogenic potential of a skeletal muscle-derived acellular scaffold and the pro-regenerative environment activated in vivo, showing clear evidence that the decellularized diaphragm is a suitable candidate for skeletal muscle tissue engineering and regeneration.

Site location and optical properties of Eu implanted sapphire

NASA Astrophysics Data System (ADS)

Marques, C.; Wemans, A.; Maneira, M. J. P.; Kozanecki, A.; da Silva, R. C.; Alves, E.

2005-10-01

Synthetic colourless transparent (0 0 0 1) sapphire crystals were implanted at room temperature with 100 keV europium ions to fluences up to 1 × 1016 cm-2. Surface damage is observed at low fluences, as seen by Rutherford backscattering spectrometry under channelling conditions. Optical absorption measurements revealed a variety of structures, most probably related to F-type defects characteristic of implantation damage. Thermal treatments in air or in vacuum up to 1000 °C do not produce noticeable changes both in the matrix or the europium profiles. However, the complete recovery of the implantation damage and some redistribution of the europium ions is achieved after annealing at 1300 °C in air. Detailed lattice site location studies performed for various axial directions allowed to assess the damage recovery and the incorporation of the Eu ions into well defined crystallographic sites, possibly in an oxide phase also inferred from optical absorption measurements.

Update on laparoscopic, robotic, and minimally invasive vaginal surgery for pelvic floor repair.

PubMed

Ross, J W; Preston, M R

2009-06-01

Advanced laparoscopic surgery marked the beginning of minimally invasive pelvic surgery. This technique lead to the development of laparoscopic hysterectomy, colposuspension, paravaginal repair, uterosacral suspension, and sacrocolpopexy without an abdominal incision. With laparoscopy there is a significant decrease in postoperative pain, shorter length of hospital stay, and a faster return to normal activities. These advantages made laparoscopy very appealing to patients. Advanced laparoscopy requires a special set of surgical skills and in the early phase of development training was not readily available. Advanced laparoscopy was developed by practicing physicians, instead of coming down through the more usual academic channels. The need for special training did hinder widespread acceptance. Nonetheless by physician to physician training and society training courses it has continued to grow and now has been incorporated in most medical school curriculums. In the last few years there has been new interest in laparoscopy because of the development of robotic assistance. The 3D vision and 720 degree articulating arms with robotics have made suture intensive procedures much easier. Laparosco-pic robotic-assisted sacrocolpopexy is in the reach of most surgeons. This field is so new that there is very little data to evaluate at this time. There are short comings with laparoscopy and even with robotic-assisted procedures it is not the cure all for pelvic floor surgery. Laparoscopic procedures are long and many patients requiring pelvic floor surgery have medical conditions preventing long anesthesia. Minimally invasive vaginal surgery has developed from the concept of tissue replacement by synthetic mesh. Initially sheets of synthetic mesh were tailored by physicians to repair the anterior and posterior vaginal compartment. The use of mesh by general surgeons for hernia repair has served as a model for urogynecology. There have been rapid improvements in biomaterials and specialized kits have been developed by industry. The purpose of this article is to present an update in urogynecologic laparoscopy, robotic surgery, and minimally invasive vaginal surgery.

PIXE study of the kinetics of biomaterials ossification

NASA Astrophysics Data System (ADS)

Weber, G.; Robaye, G.; Braye, F.; Oudadesse, H.; Irigaray, J. L.

1994-05-01

Biomaterials are frequently implanted in bones. This implantation is followed by a phenomenon of ossification. The purpose of this work was to study the time evolution of the gradient of characteristic atomic element's concentrations in the bone, the implant and the bone-implant interface. We have studied two types of neutral biomaterials: pure synthetic hydroxyapatite and porite's asteroid coral. The animal implantations have been made on sheep of the same age and sex having received the same basic diet. The implantations have been made in the cortical femur. On both sides of the implant, at the same distance, two screws were placed to allow further determination of the position of the implant. The PIXE method is particularly suitable here because of the possibility to analyze directly the samples without any preparation and to choose easily the dimensions of beam used for the gradient study. The X-rays have been detected with an ultra LEGe instead of the usual Si(Li) device to avoid the Si escape peak associated with the K α X-ray of calcium, the major constituent of bone. This peak is particularly disturbing here because its energy corresponds to the K α line of phosphorus, an important constituent of bone. The results of these determinations are presented and discussed.

Effect of personalized external aortic root support on aortic root motion and distension in Marfan syndrome patients.

PubMed

Izgi, Cemil; Nyktari, Evangelia; Alpendurada, Francisco; Bruengger, Annina Studer; Pepper, John; Treasure, Tom; Mohiaddin, Raad

2015-10-15

Personalized external aortic root support (PEARS) is a novel surgical approach with the aim of stabilizing the aortic root size and decreasing risk of dissection in Marfan syndrome patients. A bespoke polymer mesh tailored to each patient's individual aorta shape is produced by modeling and then surgically implanted. The aim of this study is to assess the mechanical effects of PEARS on the aortic root systolic downward motion (an important determinant of aortic wall stress), aortic root distension and on the left ventricle (LV). A cohort of 27 Marfan patients had a prophylactic PEARS surgery between 2004 and 2012 with 24 having preoperative and follow-up cardiovascular magnetic resonance imaging studies. Systolic downward aortic root motion, aortic root distension, LV volumes/mass and mitral annular systolic excursion before the operation and in the latest follow-up were measured randomly and blinded. After a median follow-up of 50.5 (IQR 25.5-72) months following implantation of PEARS, systolic downward motion of aortic root was significantly decreased (12.6±3.6mm pre-operation vs 7.9±2.9mm latest follow-up, p<0.00001). There was a tendency for a decrease in systolic aortic root distension but this was not significant (median 4.5% vs 2%, p=0.35). There was no significant change in LV volumes, ejection fraction, mass and mitral annular systolic excursion in follow-up. PEARS surgery decreases systolic downward aortic root motion which is an important determinant of longitudinal aortic wall stress. Aortic wall distension and Windkessel function are not significantly impaired in the follow-up after implantation of the mesh which is also supported by the lack of deterioration of LV volumes or mass. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

Modelling and structural analysis of skull/cranial implant: beyond mid-line deformities.

PubMed

Bogu, V Phanindra; Kumar, Y Ravi; Kumar Khanara, Asit

2017-01-01

This computational study explores modelling and finite element study of the implant under Intracranial pressure (ICP) conditions with normal ICP range (7 mm Hg to 15 mm Hg) or increased ICP (>I5 mm Hg). The implant fixation points allow implant behaviour with respect to intracranial pressure conditions. However, increased fixation points lead to variation in deformation and equivalent stress. Finite element analysis is providing a valuable insight to know the deformation and equivalent stress. The patient CT data (Computed Tomography) is processed in Mimics software to get the mesh model. The implant is modelled by using modified reverse engineering technique with the help of Rhinoceros software. This modelling method is applicable for all types of defects including those beyond the middle line and multiple ones. It is designed with eight fixation points and ten fixation points to fix an implant. Consequently, the mechanical deformation and equivalent stress (von Mises) are calculated in ANSYS 15 software with distinctive material properties such as Titanium alloy (Ti6Al4V), Polymethyl methacrylate (PMMA) and polyether-ether-ketone (PEEK). The deformation and equivalent stress results are obtained through ANSYS 15 software. It is observed that Ti6Al4V material shows low deformation and PEEK material shows less equivalent stress. Among all materials PEEK shows noticeably good result. Hence, a concept was established and more clinically relevant results can be expected with implementation of realistic 3D printed model in the future. This will allow physicians to gain knowledge and decrease surgery time with proper planning.

42 CFR 419.66 - Transitional pass-through payments: Medical devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... replace human skin (for example, a biological skin replacement material or synthetic skin replacement... HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEM FOR HOSPITAL OUTPATIENT... human tissue, and is surgically implanted or inserted whether or not it remains with the patient when...

42 CFR 419.66 - Transitional pass-through payments: Medical devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... replace human skin (for example, a biological skin replacement material or synthetic skin replacement... HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEM FOR HOSPITAL OUTPATIENT... human tissue, and is surgically implanted or inserted whether or not it remains with the patient when...

Polymeric scaffolds as stem cell carriers in bone repair.

PubMed

Rossi, Filippo; Santoro, Marco; Perale, Giuseppe

2015-10-01

Although bone has a high potential to regenerate itself after damage and injury, the efficacious repair of large bone defects resulting from resection, trauma or non-union fractures still requires the implantation of bone grafts. Materials science, in conjunction with biotechnology, can satisfy these needs by developing artificial bones, synthetic substitutes and organ implants. In particular, recent advances in polymer science have provided several innovations, underlying the increasing importance of macromolecules in this field. To address the increasing need for improved bone substitutes, tissue engineering seeks to create synthetic, three-dimensional scaffolds made from polymeric materials, incorporating stem cells and growth factors, to induce new bone tissue formation. Polymeric materials have shown a great affinity for cell transplantation and differentiation and, moreover, their structure can be tuned in order to maintain an adequate mechanical resistance and contemporarily be fully bioresorbable. This review emphasizes recent progress in polymer science that allows relaible polymeric scaffolds to be synthesized for stem cell growth in bone regeneration. Copyright © 2013 John Wiley & Sons, Ltd.

Characterization of synthetic foam structures used to manufacture artificial vertebral trabecular bone.

PubMed

Fürst, David; Senck, Sascha; Hollensteiner, Marianne; Esterer, Benjamin; Augat, Peter; Eckstein, Felix; Schrempf, Andreas

2017-07-01

Artificial materials reflecting the mechanical properties of human bone are essential for valid and reliable implant testing and design. They also are of great benefit for realistic simulation of surgical procedures. The objective of this study was therefore to characterize two groups of self-developed synthetic foam structures by static compressive testing and by microcomputed tomography. Two mineral fillers and varying amounts of a blowing agent were used to create different expansion behavior of the synthetic open-cell foams. The resulting compressive and morphometric properties thus differed within and also slightly between both groups. Apart from the structural anisotropy, the compressive and morphometric properties of the synthetic foam materials were shown to mirror the respective characteristics of human vertebral trabecular bone in good approximation. In conclusion, the artificial materials created can be used to manufacture valid synthetic bones for surgical training. Further, they provide novel possibilities for studying the relationship between trabecular bone microstructure and biomechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Nasal base, maxillary, and infraorbital implants--alloplastic.

PubMed

Hinderer, U T

1991-01-01

The aesthetic surgery of the facial skeletal contour requires either the performance of ostectomies of excessively prominent segments or the augmentation of retruded segments with organic or synthetic material, in order to achieve balanced tridimensional relations of each segment with regard to the total facial unit. Craniomaxillofacial surgeries are necessary in major malformations or in those combined with malocclusion. In the nasal dorsum or tip, the author prefers the use of cartilage, because synthetic materials need adequate soft-tissue bulk for cover to be inserted without tension and absence of passive mobility of the reception site. For malar augmentation, first proposed by the author and independently by Spadafora in 1971, for chin augmentation up to 8 mm, and for augmentation of the mandibular angle, the author prefers silicone implants because they do not change in shape or volume, may be premanufactured or custom-made, have a similar consistency to that of bone, and do not support bacterial growth. On the other hand, autologous bone grafts adapt less to curved bony surfaces, have an erratic rate of resorption, and need an additional surgical step for removal with the corresponding morbidity and scar. Subperiosteal insertion is preferred because it confers greater stability and the cavity is easier to dissect without soft-tissue damage. Although bone erosion may occur, with over 1200 implants clinically no major change in the soft-tissue contour has been observed, nor has the author been consulted for late complication. In the malar region this may be due to the large surface of the implant and absence of muscular pressure. In the chin, an insertion over the site of the dental roots is avoided. For midface augmentation the following implants are used: (1) The premaxillary lower nasal base implant, proposed in 1971, is indicated to correct a concave midfacial profile, frequent in Asian, black, and Mestizo patients from Latin America and in Caucasian patients with maxillonasal dysplasia or Binder's syndrome, after trauma, with excessive septum and nasal spine resections, and in nasal-maxillary sequels in cleft patients. In case of dental malocclusion, orthognathic surgery is the technique of choice. A prototype implant is available in two sizes, to be inserted through a lateral incision at the base of the columella. In 108 patients two implants have been partially removed. After the first month the patient is usually well adapted to the foreign body.(ABSTRACT TRUNCATED AT 400 WORDS)

TRAP-Positive Multinucleated Giant Cells Are Foreign Body Giant Cells Rather Than Osteoclasts: Results From a Split-Mouth Study in Humans.

PubMed

Lorenz, Jonas; Kubesch, Alica; Korzinskas, Tadas; Barbeck, Mike; Landes, Constantin; Sader, Robert A; Kirkpatrick, Charles J; Ghanaati, Shahram

2015-12-01

This study compared the material-specific tissue response to the synthetic, hydroxyapatite-based bone substitute material NanoBone (NB) with that of the xenogeneic, bovine-based bone substitute material Bio-Oss (BO). The sinus cavities of 14 human patients were augmented with NB and BO in a split-mouth design. Six months after augmentation, bone biopsies were extracted for histological and histomorphometric investigation prior to dental implant insertion. The following were evaluated: the cellular inflammatory pattern, the induction of multinucleated giant cells, vascularization, the relative amounts of newly formed bone, connective tissue, and the remaining bone substitute material. NB granules were well integrated in the peri-implant tissue and were surrounded by newly formed bone tissue. Multinucleated giant cells were visible on the surfaces of the remaining granules. BO granules were integrated into the newly formed bone tissue, which originated from active osteoblasts on their surface. Histomorphometric analysis showed a significantly higher number of multinucleated giant cells and blood vessels in the NB group compared to the BO group. No statistical differences were observed in regard to connective tissue, remaining bone substitute, and newly formed bone. The results of this study highlight the different cellular reactions to synthetic and xenogeneic bone substitute materials. The significantly higher number of multinucleated giant cells within the NB implantation bed seems to have no effect on its biodegradation. Accordingly, the multinucleated giant cells observed within the NB implantation bed have characteristics more similar to those of foreign body giant cells than to those of osteoclasts.

Finite element analysis of TAVI: Impact of native aortic root computational modeling strategies on simulation outcomes.

PubMed

Finotello, Alice; Morganti, Simone; Auricchio, Ferdinando

2017-09-01

In the last few years, several studies, each with different aim and modeling detail, have been proposed to investigate transcatheter aortic valve implantation (TAVI) with finite elements. The present work focuses on the patient-specific finite element modeling of the aortic valve complex. In particular, we aim at investigating how different modeling strategies in terms of material models/properties and discretization procedures can impact analysis results. Four different choices both for the mesh size (from  20 k elements to  200 k elements) and for the material model (from rigid to hyperelastic anisotropic) are considered. Different approaches for modeling calcifications are also taken into account. Post-operative CT data of the real implant are used as reference solution with the aim of outlining a trade-off between computational model complexity and reliability of the results. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Integration of implant planning workflows into the PACS infrastructure

NASA Astrophysics Data System (ADS)

Gessat, Michael; Strauß, Gero; Burgert, Oliver

2008-03-01

The integration of imaging devices, diagnostic workstations, and image servers into Picture Archiving and Communication Systems (PACS) has had an enormous effect on the efficiency of radiology workflows. The standardization of the information exchange between the devices with the DICOM standard has been an essential precondition for that development. For surgical procedures, no such infrastructure exists. With the increasingly important role computerized planning and assistance systems play in the surgical domain, an infrastructure that unifies the communication between devices becomes necessary. In recent publications, the need for a modularized system design has been established. A reference architecture for a Therapy Imaging and Model Management System (TIMMS) has been proposed. It was accepted by the DICOM Working Group 6 as the reference architecture for DICOM developments for surgery. In this paper we propose the inclusion of implant planning systems into the PACS infrastructure. We propose a generic information model for the patient specific selection and positioning of implants from a repository according to patient image data. The information models are based on clinical workflows from ENT, cardiac, and orthopedic surgery as well as technical requirements derived from different use cases and systems. We show an exemplary implementation of the model for application in ENT surgery: the selection and positioning of an ossicular implant in the middle ear. An implant repository is stored in the PACS. It makes use of an experimental implementation of the Surface Mesh Module that is currently being developed as extension to the DICOM standard.

Biomimetic fiber mesh scaffolds based on gelatin and hydroxyapatite nano-rods: Designing intrinsic skills to attain bone reparation abilities.

PubMed

Sartuqui, Javier; Gravina, A Noel; Rial, Ramón; Benedini, Luciano A; Yahia, L'Hocine; Ruso, Juan M; Messina, Paula V

2016-09-01

Intrinsic material skills have a deep effect on the mechanical and biological performance of bone substitutes, as well as on its associated biodegradation properties. In this work we have manipulated the preparation of collagenous derived fiber mesh frameworks to display a specific composition, morphology, open macroporosity, surface roughness and permeability characteristics. Next, the effect of the induced physicochemical attributes on the scaffold's mechanical behavior, bone bonding potential and biodegradability were evaluated. It was found that the scaffold microstructure, their inherent surface roughness, and the compression strength of the gelatin scaffolds can be modulated by the effect of the cross-linking agent and, essentially, by mimicking the nano-scale size of hydroxyapatite in natural bone. A clear effect of bioactive hydroxyapatite nano-rods on the scaffolds skills can be appreciated and it is greater than the effect of the cross-linking agent, offering a huge perspective for the upcoming progress of bone implant technology. Copyright © 2016 Elsevier B.V. All rights reserved.

Inflammatory reaction to fabric collars from percutaneous antennas attached to intracoelomic radio transmitters implanted in harlequin ducks (Histrionicus histrionicus)

USGS Publications Warehouse

Mulcahy, Daniel M.; Burek, K.A.; Esler, Daniel N.

2007-01-01

In wild birds implanted intracoelomically with radio transmitters, a synthetic fabric collar placed around the base of a percutaneous antenna is believed to function as a barrier to contamination of the coelom. We examined 13 fabric collars recovered from percutaneous antennas of radio transmitters implanted intracoelomically in harlequin ducks (Histrionicus histrionicus) 12 months earlier. Both the transmitters and antenna collars were encapsulated in fibrous connective tissue, with adhesions to internal organs. Histologically, bacteria were evident at the fabric-plastic interface in 8 of 10 collars examined in cross section and along the length of the collar in 3 collars examined longitudinally. Bacteria were confined within the fibrotic sheath surrounding the transmitter and the antenna collar in all birds. No evidence of chronic systemic effects secondary to implantation was present on hematologic or serum biochemical testing. These findings indicate that antenna collars do not prevent the entry of bacteria along the percutaneous antenna but may help stabilize the antenna and minimize coelomic contamination. We conclude that radio transmitters implanted into the coelom of harlequin ducks do not appear to cause significant health problems for at least 1 year after implantation.

Current requirements for polymeric biomaterials in otolaryngology

PubMed Central

Sternberg, Katrin

2011-01-01

In recent years otolaryngology was strongly influenced by newly developed implants which are based on both, innovative biomaterials and novel implant technologies. Since the biomaterials are integrated into biological systems they have to fulfill all technical requirements and accommodate biological interactions. Technical functionality relating to implant specific mechanical properties, a sufficiently high stability in terms of physiological conditions, and good biocompatibility are the demands with regard to suitability of biomaterials. The goal in applying biomaterials for implants is to maintain biofunctionality over extended periods of time. These general demands to biomaterials are equally valid for use in otolaryngology. Different classes of materials can be utilized as biomaterials. Metals belong to the oldest biomaterials. In addition, alloys, ceramics, inorganic glasses and composites have been tested successfully. Furthermore, natural and synthetic polymers are widely used materials, which will be in the focus of the current article with regard to their properties and usage as cochlear implants, osteosynthesis implants, stents, and matrices for tissue engineering. Due to their application as permanent or temporary implants materials are differentiated into biostable and biodegradable polymers. The here identified general and up to date requirements for biomaterials and the illustrated applications in otolaryngology emphasize ongoing research efforts in this area and at the same time demonstrate the high significance of interdisciplinary cooperation between natural sciences, engineering, and medical sciences. PMID:22073104

The advantages of advanced computer-assisted diagnostics and three-dimensional preoperative planning on implant position in orbital reconstruction.

PubMed

Jansen, Jesper; Schreurs, Ruud; Dubois, Leander; Maal, Thomas J J; Gooris, Peter J J; Becking, Alfred G

2018-04-01

Advanced three-dimensional (3D) diagnostics and preoperative planning are the first steps in computer-assisted surgery (CAS). They are an integral part of the workflow, and allow the surgeon to adequately assess the fracture and to perform virtual surgery to find the optimal implant position. The goal of this study was to evaluate the accuracy and predictability of 3D diagnostics and preoperative virtual planning without intraoperative navigation in orbital reconstruction. In 10 cadaveric heads, 19 complex orbital fractures were created. First, all fractures were reconstructed without preoperative planning (control group) and at a later stage the reconstructions were repeated with the help of preoperative planning. Preformed titanium mesh plates were used for the reconstructions by two experienced oral and maxillofacial surgeons. The preoperative virtual planning was easily accessible for the surgeon during the reconstruction. Computed tomographic scans were obtained before and after creation of the orbital fractures and postoperatively. Using a paired t-test, implant positioning accuracy (translation and rotations) of both groups were evaluated by comparing the planned implant position with the position of the implant on the postoperative scan. Implant position improved significantly (P < 0.05) for translation, yaw and roll in the group with preoperative planning (Table 1). Pitch did not improve significantly (P = 0.78). The use of 3D diagnostics and preoperative planning without navigation in complex orbital wall fractures has a positive effect on implant position. This is due to a better assessment of the fracture, the possibility of virtual surgery and because the planning can be used as a virtual guide intraoperatively. The surgeon has more control in positioning the implant in relation to the rim and other bony landmarks. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Proximal tibial strain in medial unicompartmental knee replacements: A biomechanical study of implant design.

PubMed

Scott, C E H; Eaton, M J; Nutton, R W; Wade, F A; Pankaj, P; Evans, S L

2013-10-01

As many as 25% to 40% of unicompartmental knee replacement (UKR) revisions are performed for pain, a possible cause of which is proximal tibial strain. The aim of this study was to examine the effect of UKR implant design and material on cortical and cancellous proximal tibial strain in a synthetic bone model. Composite Sawbone tibiae were implanted with cemented UKR components of different designs, either all-polyethylene or metal-backed. The tibiae were subsequently loaded in 500 N increments to 2500 N, unloading between increments. Cortical surface strain was measured using a digital image correlation technique. Cancellous damage was measured using acoustic emission, an engineering technique that detects sonic waves ('hits') produced when damage occurs in material. Anteromedial cortical surface strain showed significant differences between implants at 1500 N and 2500 N in the proximal 10 mm only (p < 0.001), with relative strain shielding in metal-backed implants. Acoustic emission showed significant differences in cancellous bone damage between implants at all loads (p = 0.001). All-polyethylene implants displayed 16.6 times the total number of cumulative acoustic emission hits as controls. All-polyethylene implants also displayed more hits than controls at all loads (p < 0.001), more than metal-backed implants at loads ≥ 1500 N (p < 0.001), and greater acoustic emission activity on unloading than controls (p = 0.01), reflecting a lack of implant stiffness. All-polyethylene implants were associated with a significant increase in damage at the microscopic level compared with metal-backed implants, even at low loads. All-polyethylene implants should be used with caution in patients who are likely to impose large loads across their knee joint.

Evaluation of Hi-Tec Implant Restoration in Mandibular First Molar Region- A Prospective Clinical Study.

PubMed

Sreeram, Roopa Rani S; Prasad, L Krishna; Chakravarthi, P Srinivas; Devi, Naga Neelima; Kattimani, Vivekanand S; Sreeram, Sanjay Krishna

2015-08-01

Missing teeth lead to loss of structural balance, inefficient function, poor aesthetics and psychological effects on human beings, which needs restoration for normal contour, function and aesthetics. Several natural or synthetic substitutes are being used for replacement of missing tooth since centuries. Implants are the latest modality of replacement. So, the study was aimed to assess clinical success rate of Hi-Tec implant; which is economical and new in market. Results of the study will help clinician for appropriate implant selection. The study included 10 patients from 19 to 31 years and needed restoration of missing mandibular first molar. Restoration had done using Hi Tec Single-tooth implants with metal-ceramic single crown prosthesis after three months of osseointegration. The implants were evaluated clinically (bleeding on probing, probing depth, implant mobility- periotest) and radiographically (marginal bone loss and peri-implant radiolucency) for six years. The observers were blinded for the duration of the study to prevent bias. All the patients had uneventful post-surgical healing. No bleeding on probing, Implant mobility, peri-implant radiolucency with minimal marginal bone loss and constant probing depths were observed well within the normal range during follow-up periods. Two stage single-tooth Hi Tec implant restoration can be used as a successful treatment modality for replacing mandibular first molar in an economic way. However, these results were obtained after 6 years of follow up with a smaller sample size, so long term multi center studies with a larger sample size is recommended for the predictability of success rate conclusively.

Estrus synchronization in sheep with synthetic progestagens.

PubMed

Awel, Hayatu; Eshetu, Lisanework; Tadesse, Gebrehiwot; Birhanu, Alemselam; Khar, S K

2009-10-01

Sixteen female sheep of Degua breed were assigned to receive either the full dose of norgestomet ear implant and injectable solution containing norgestomet and estradiol valerate (n = 8) or half the dose (n = 8). The ear implants were removed in both groups on day 12. All ewes received an intramuscular administration of 500 IU PMSG at implant withdrawal. Synchronized ewes were individually hand mated twice at 48 and 60 hours after implant removal. One ewe in each group however refused mating on both occasions. Pregnancy diagnosis was conducted by bimanual external palpation 90 to 100 days post mating. The conception rates (3/7, 42.85%) and (5/7, 71.42%) were recorded in the two treatment groups, respectively. All eight ewes lambed between 145 to 153 days post mating. In group I ewes carried only singletons (prolificity rate 1.0) whereas in group II two ewes delivered twins, producing 7 lambs with prolificity rate of 1.4 (N.S). From this preliminary investigation it appears that the lower dose of norgestomet ear implants offers better option for estrus synchronization accompanied by higher fertility.

Ischiorectal abscess and ischiorectal-vaginal fistula as delayed complications of posterior intravaginal slingplasty: a case report.

PubMed

Chen, Heidi Wen-Chu; Guess, Marsha K; Connell, Kathleen A; Bercik, Richard S

2009-10-01

Synthetic meshes have been used extensively to augment surgical management of pelvic organ prolapses. Posterior intravaginal sling (IVS) is a technique used for correcting vaginal vault/apical prolapse, posterior vaginal prolapse or rectocele. There are limited data on long-term safety of this procedure. In a subanalysis of the IVS tapes from the SUSPEND trial performed secondary to the large number of patients with complications of suburethral sling erosions after IVS, it was noted that the sling erosion tended to have a delayed presentation secondary to poor incorporation of the mesh. A 48-year-old woman with cystocele, uterine prolapse and rectocele had undergone total vaginal hysterectomy, mesh-augmented anterior repair, posterior colporrhaphy and posterior intravaginal slingplasty (IVS) in July 2005. Thirty months after the surgery, she presented with gradual symptoms of copious vaginal discharge for several weeks followed by constant right buttock pain and swelling. Examination was notable for intact mesh with no signs of erosion and a 3-cm induration deep within the right buttock. Computed tomography suggested a pelvic abscess. Magnetic resonance imaging confirmed a right ischiorectal fossa abscess and a vaginal fistula. The patient underwent sling excision, right ischiorectal fossa exploration and vaginal fistula repair. A fistulous tract was found to extend along the intact sling from the vaginal epithelium toward the right ischiorectal fossa. At 2 months' followup, there were no recurrences or other complications. This is the first report of a delayed complication of an ischiorectal abscess associated with an ischiorectal-vaginal fistula that presented 30 months after the placement of a posterior IVS.

Evidence for the use of "medical marijuana" in psychiatric and neurologic disorders.

PubMed

Noel, Christopher

2017-01-01

Cannabis is listed as a Schedule I substance under the Controlled Substances Act of 1970, meaning the US federal government defines it as an illegal drug that has high potential for abuse and no established medical use; however, half of the states in the nation have enacted "medical marijuana" (MM) laws. Clinicians must be aware of the evidence for and against the use of MM in their patients who may consider using this substance. A PubMed database search was performed using the text string: "Cannabis"[Mesh] OR "Marijuana Abuse"[Mesh] OR "Medical Marijuana"[Mesh] OR "Marijuana Smoking"[Mesh] OR "cannabi*" OR "tetrahydrocannabinol." The search was further limited to randomized clinical trial publications in English on human subjects to identify articles regarding the therapeutic use of phytocannabinoids for psychiatric and neurologic disorders. Commercially available products (ie, dronabinol, nabilone, nabiximols) and synthetic cannabinoids were excluded from the review. Publications were identified that included patients with dementia, multiple sclerosis, Parkinson disease, Huntington disease, schizophrenia, social anxiety disorder, depression, tobacco use disorder, and neuropathic pain. There is great variety concerning which medical conditions are approved for treatment with MM for either palliative or therapeutic benefit, depending on the state law. It is important to keep an evidence-based approach in mind, even with substances considered to be illegal under US federal law. Clinicians must weigh risks and benefits of the use of MM in their patients and should ensure that patients have tried other treatment modalities with higher levels of evidence for use when available and appropriate.

Stress distribution of single-implant-retained overdenture reinforced with a framework: A finite element analysis study.

PubMed

Amaral, Camilla F; Gomes, Rafael S; Rodrigues Garcia, Renata C M; Del Bel Cury, Altair A

2018-05-01

Studies have demonstrated the effectiveness of a single-implant-retained mandibular overdenture for elderly patients with edentulism. However, due to the high concentration of stress around the housing portion of the single implant, this prosthesis tends to fracture at the anterior region more than the 2-implant-retained mandibular overdenture. The purpose of this finite-element analysis study was to evaluate the stress distribution in a single-implant-retained mandibular overdenture reinforced with a cobalt-chromium framework, to minimize the incidence of denture base fracture. Two 3-dimensional finite element models of mandibular overdentures supported by a single implant with a stud attachment were designed in SolidWorks 2013 software. The only difference between the models was the presence or absence of a cobalt-chromium framework at the denture base between canines. Subsequently, the models were imported into the mathematical analysis software ANSYS Workbench v15.0. A mesh was generated with an element size of 0.7 mm and submitted to convergence analysis before mechanical simulation. All materials were considered to be homogeneous, isotropic, and linearly elastic. A 100-N load was applied to the incisal edge of the central mandibular incisors at a 30-degree angle. Maximum principal stress was calculated for the overdenture, von Mises stress was calculated for the attachment and implant, and minimum principal stress was calculated for cortical and cancellous bone. In both models, peak stress on the overdenture was localized at the anterior intaglio surface region around the implant. However, the presence of the framework reduced the stress by almost 62% compared with the overdenture without a framework (8.7 MPa and 22.8 MPa, respectively). Both models exhibited similar stress values in the attachment, implant, and bone. A metal framework reinforcement for a single-implant-retained mandibular overdenture concentrates less stress through the anterior area of the prosthesis and could minimize the incidence of fracture. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Mini-implants for Orthodontic Anchorage: Surface Analysis after Redrilling and Sterilization - An in vitro Study.

PubMed

Gross, J M; Nascimento, G G; Araújo, V C; Bönecker, Mjs; Furuse, C

2016-04-01

This study aimed to investigate, in vitro, possible alterations on mini-implants surface after retrieval and if the cleaning process and sterilization can predispose damages. Two commercial mini-implants were tested for deformations after drilling and removing in artificial bone four times. Samples were analyzed by scanning electron microscopy, and surface alterations verified through thread and pitches deformation. To alterations caused by insertion/removal and the cleaning process and sterilization were verified in different procedures: Insertions and sterilization, only insertions, and only sterilization. Photomicrographs were analyzed in order to compare the surface characteristics. Head deformation was verified qualitatively. For a quantitative analysis, distances between threads were measured across the active part of the mini-implants. No deformation was observed in both groups. The cleaning and sterilization processes did not provoke alteration in both groups. Nevertheless, the presence of synthetic bone was noted in some samples. The mean distances between implant threads were similar after all steps in all regions in both groups. The results suggest that the tested mini-implants can be retrieved without damage of its surface after four cycles of insertion, removal, and sterilization. Orthodontic mini-implant, Redrilling, Sterilization. Mini-implants can be retrieved without damage to its surface after four cycles of insertion, removal, and sterilization in the same patient without representing a biological concern.

Nanomaterials and synergistic low intensity direct current (LIDC) stimulation technology for orthopaedic implantable medical devices

PubMed Central

Samberg, Meghan E.; Cohen, Paul H.; Wysk, Richard A.; Monteiro-Riviere, Nancy A.

2012-01-01

Nanomaterials play a significant role in biomedical research and applications due to their unique biological, mechanical, and electrical properties. In recent years, they have been utilised to improve the functionality and reliability of a wide range of implantable medical devices ranging from well-established orthopaedic residual hardware devices (e.g. hip implants) that can repair defects in skeletal systems to emerging tissue engineering scaffolds that can repair or replace organ functions. This review summarizes the applications and efficacies of these nanomaterials that include synthetic or naturally occurring metals, polymers, ceramics, and composites in orthopaedic implants, the largest market segment of implantable medical devices. The importance of synergistic engineering techniques that can augment or enhance the performance of nanomaterial applications in orthopaedic implants is also discussed,, the focus being on a low intensity direct electric current (LIDC) stimulation technology to promote the long-term antibacterial efficacy of oligodynamic metal-based surfaces by ionization, while potentially accelerating tissue growth and osseointegration. While many nanomaterials have clearly demonstrated their ability to provide more effective implantable medical surfaces, further decisive investigations are necessary before they can translate into medically safe and commercially viable clinical applications. The paper concludes with a discussion about some of the critical impending issues with the application of nanomaterials-based technologies in implantable medical devices, and potential directions to address these. PMID:23335493

Osseointegration of dental implants in 3D-printed synthetic onlay grafts customized according to bone metabolic activity in recipient site.

PubMed

Tamimi, Faleh; Torres, Jesus; Al-Abedalla, Khadijeh; Lopez-Cabarcos, Enrique; Alkhraisat, Mohammad H; Bassett, David C; Gbureck, Uwe; Barralet, Jake E

2014-07-01

Onlay grafts made of monolithic microporous monetite bioresorbable bioceramics have the capacity to conduct bone augmentation. However, there is heterogeneity in the graft behaviour in vivo that seems to correlate with the host anatomy. In this study, we sought to investigate the metabolic activity of the regenerated bone in monolithic monetite onlays by using positron emission tomography-computed tomography (PET-CT) in rats. This information was used to optimize the design of monetite onlays with different macroporous architecture that were then fabricated using a 3D-printing technique. In vivo, bone augmentation was attempted with these customized onlays in rabbits. PET-CT findings demonstrated that bone metabolism in the calvarial bone showed higher activity in the inferior and lateral areas of the onlays. Histological observations revealed higher bone volume (up to 47%), less heterogeneity and more implant osseointegration (up to 38%) in the augmented bone with the customized monetite onlays. Our results demonstrated for the first time that it is possible to achieve osseointegration of dental implants in bone augmented with 3D-printed synthetic onlays. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within monetite onlays. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bone bonding in bioactive glass ceramics combined with a new synthesized agent TAK-778.

PubMed

Kato, H; Neo, M; Tamura, J; Nakamura, T

2001-11-01

We studied the stimulatory effects of TAK-778, a new synthetic 3-benzothiepin derivative that promotes osteoblast differentiation, in the bonding of bone to bioactive glass ceramic implants in rabbit tibiae. Smooth-surfaced, rectangular plates (15 x 10 x 2 mm) made of apatite-wollastonite-containing glass ceramic were implanted bilaterally into the proximal metaphyses of rabbit tibiae. Sustained-release microcapsules containing TAK-778 were packed into the medullary cavity in one limb and untreated microcapsules were packed into the contralateral limb to serve as a paired control. At 4, 8, and 16 weeks after implantation, bonding at the bone/implant interfaces was evaluated using a detaching test and histological examination of undecalcified specimens. The tensile failure load increased during weeks 4 to 16 in both groups; the tensile failure load in the TAK-778-treated group was significantly greater than that in the control group at each interval after implantation. Histologically, the TAK-778-treated specimens showed greater active new bone formation mainly in the medullary cavity and more extensive bonding between the implant and bone than the untreated specimens. The results of this study suggest that adding the bone formation-promoting TAK-778 to bioactive glass ceramic implants may significantly accelerate bone apposition to the implants and improve the bonding process at the interface. This would help to establish earlier and stronger bonding of orthopedic ceramic implants to the surrounding bone tissue. Copyright 2001 John Wiley & Sons, Inc.

Localized Immunosuppressive Environment in the Foreign Body Response to Implanted Biomaterials

PubMed Central

Higgins, David M.; Basaraba, Randall J.; Hohnbaum, April C.; Lee, Eric J.; Grainger, David W.; Gonzalez-Juarrero, Mercedes

2009-01-01

The implantation of synthetic biomaterials initiates the foreign body response (FBR), which is characterized by macrophage infiltration, foreign body giant cell formation, and fibrotic encapsulation of the implant. The FBR is orchestrated by a complex network of immune modulators, including diverse cell types, soluble mediators, and unique cell surface interactions. The specific tissue locations, expression patterns, and spatial distribution of these immune modulators around the site of implantation are not clear. This study describes a model for studying the FBR in vivo and specifically evaluates the spatial relationship of immune modulators. We modified a biomaterials implantation in vivo model that allowed for cross-sectional in situ analysis of the FBR. Immunohistochemical techniques were used to determine the localization of soluble mediators, ie, interleukin (IL)-4, IL-13, IL-10, IL-6, transforming growth factor-β, tumor necrosis factor-α, interferon-γ, and MCP-1; specific cell types, ie, macrophages, neutrophils, fibroblasts, and lymphocytes; and cell surface markers, ie, F4/80, CD11b, CD11c, and Ly-6C, at early, middle, and late stages of the FBR in subcutaneous implant sites. The cytokines IL-4, IL-13, IL-10, and transforming growth factor-β were localized to implant-adherent cells that included macrophages and foreign body giant cells. A better understanding of the FBR in vivo will allow the development of novel strategies to enhance biomaterial implant design to achieve better performance and safety of biomedical devices at the site of implant. PMID:19528351

Localized immunosuppressive environment in the foreign body response to implanted biomaterials.

PubMed

Higgins, David M; Basaraba, Randall J; Hohnbaum, April C; Lee, Eric J; Grainger, David W; Gonzalez-Juarrero, Mercedes

2009-07-01

The implantation of synthetic biomaterials initiates the foreign body response (FBR), which is characterized by macrophage infiltration, foreign body giant cell formation, and fibrotic encapsulation of the implant. The FBR is orchestrated by a complex network of immune modulators, including diverse cell types, soluble mediators, and unique cell surface interactions. The specific tissue locations, expression patterns, and spatial distribution of these immune modulators around the site of implantation are not clear. This study describes a model for studying the FBR in vivo and specifically evaluates the spatial relationship of immune modulators. We modified a biomaterials implantation in vivo model that allowed for cross-sectional in situ analysis of the FBR. Immunohistochemical techniques were used to determine the localization of soluble mediators, ie, interleukin (IL)-4, IL-13, IL-10, IL-6, transforming growth factor-beta, tumor necrosis factor-alpha, interferon-gamma, and MCP-1; specific cell types, ie, macrophages, neutrophils, fibroblasts, and lymphocytes; and cell surface markers, ie, F4/80, CD11b, CD11c, and Ly-6C, at early, middle, and late stages of the FBR in subcutaneous implant sites. The cytokines IL-4, IL-13, IL-10, and transforming growth factor-beta were localized to implant-adherent cells that included macrophages and foreign body giant cells. A better understanding of the FBR in vivo will allow the development of novel strategies to enhance biomaterial implant design to achieve better performance and safety of biomedical devices at the site of implant.

Structural and mechanical implications of PMMA implant shape and interface geometry in cranioplasty--A finite element study.

PubMed

Ridwan-Pramana, Angela; Marcián, Petr; Borák, Libor; Narra, Nathaniel; Forouzanfar, Tim; Wolff, Jan

2016-01-01

This computational study investigates the effect of shape (defect contour curvature) and bone-implant interface (osteotomy angle) on the stress distribution within PMMA skull implants. Using finite element methodology, 15 configurations--combinations of simplified synthetic geometric shapes (circular, square, triangular, irregular) and interface angulations--were simulated under 50N static loads. Furthermore, the implant fixation devices were modelled and analysed in detail. Negative osteotomy configurations demonstrated the largest stresses in the implant (275 MPa), fixation devices (1258 MPa) and bone strains (0.04). The circular implant with zero and positive osteotomy performed well with maximum observed magnitudes of--implant stress (1.2 MPa and 1.2 MPa), fixation device stress (11.2 MPa and 2.2 MPa), bone strain (0.218e-3 and 0.750e-4). The results suggest that the preparation of defect sites is a critical procedure. Of the greatest importance is the angle at which the edges of the defect are sawed. If under an external load, the implant has no support from the interface and the stresses are transferred to the fixation devices. This can endanger their material integrity and lead to unphysiological strains in the adjacent bone, potentially compromising the bone morphology required for anchoring. These factors can ultimately weaken the stability of the entire implant assembly. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Planning the Surgical Correction of Spinal Deformities: Toward the Identification of the Biomechanical Principles by Means of Numerical Simulation

PubMed Central

Galbusera, Fabio; Bassani, Tito; La Barbera, Luigi; Ottardi, Claudia; Schlager, Benedikt; Brayda-Bruno, Marco; Villa, Tomaso; Wilke, Hans-Joachim

2015-01-01

In decades of technical developments after the first surgical corrections of spinal deformities, the set of devices, techniques, and tools available to the surgeons has widened dramatically. Nevertheless, the rate of complications due to mechanical failure of the fixation or the instrumentation remains rather high. Indeed, basic and clinical research about the principles of deformity correction and the optimal surgical strategies (i.e., the choice of the fusion length, the most appropriate instrumentation, and the degree of tolerable correction) did not progress as much as the implantable devices and the surgical techniques. In this work, a software approach for the biomechanical simulation of the correction of patient-specific spinal deformities aimed to the identification of its biomechanical principles is presented. The method is based on three-dimensional reconstructions of the spinal anatomy obtained from biplanar radiographic images. A user-friendly graphical user interface allows for the planning of the desired deformity correction and to simulate the implantation of pedicle screws. Robust meshing of the instrumented spine is provided by using consolidated computational geometry and meshing libraries. Based on a finite element simulation, the program is able to predict the loads and stresses acting in the instrumentation as well as those in the biological tissues. A simple test case (reduction of a low-grade spondylolisthesis at L3–L4) was simulated as a proof of concept, and showed plausible results. Despite the numerous limitations of this approach which will be addressed in future implementations, the preliminary outcome is promising and encourages a wide effort toward its refinement. PMID:26579518

DOE Office of Scientific and Technical Information (OSTI.GOV)

Midulla, Marco, E-mail: marco.midulla@chru-lille.fr; Moreno, Ramiro, E-mail: ramoroa@gmail.com; Negre-Salvayre, Anne, E-mail: anne.negre-salvayre@inserm.fr

PurposeAlthough the widespread acceptance of thoracic endovascular aortic repair (TEVAR) as a first-line treatment option for a multitude of thoracic aortic diseases, little is known about the consequences of the device implantation on the native aortic anatomy. We propose a comparative analysis of the pre- and postoperative geometry on a clinical series of patients and discuss the potential clinical implicationsMethodsCT pre- and postoperative acquisitions of 30 consecutive patients treated by TEVAR for different pathologies (20 thoracic aortic aneurysms, 6 false aneurysms, 3 penetrating ulcers, 1 traumatic rupture) were used to model the vascular geometry. Pre- and postoperative geometries were comparedmore » for each patient by pairing and matching the 3D models. An implantation site was identified, and focal differences were detected and described.ResultsSegmentation of the data sets was successfully performed for all 30 subjects. Geometry differences between the pre- and postoperative meshes were depicted in 23 patients (76 %). Modifications at the upper implantation site were detected in 14 patients (47 %), and among them, the implantation site involved the arch (Z0–3) in 11 (78 %).ConclusionModeling the vascular geometry on the basis of imaging data offers an effective tool to perform patient-specific analysis of the vascular geometry before and after the treatment. Future studies will evaluate the consequences of these changes on the aortic function.« less

Emerging technologies in arthroplasty: additive manufacturing.

PubMed

Banerjee, Samik; Kulesha, Gene; Kester, Mark; Mont, Michael A

2014-06-01

Additive manufacturing is an industrial technology whereby three-dimensional visual computer models are fabricated into physical components by selectively curing, depositing, or consolidating various materials in consecutive layers. Although initially developed for production of simulated models, the technology has undergone vast improvements and is currently increasingly being used for the production of end-use components in various aerospace, automotive, and biomedical specialties. The ability of this technology to be used for the manufacture of solid-mesh-foam monolithic and coated components of complex geometries previously considered unmanufacturable has attracted the attention of implant manufacturers, bioengineers, and orthopedic surgeons. Currently, there is a paucity of reports describing this fabrication method in the orthopedic literature. Therefore, we aimed to briefly describe this technology, some of the applications in other orthopedic subspecialties, its present use in hip and knee arthroplasty, and concerns with the present form of the technology. As there are few reports of clinical trials presently available, the true benefits of this technology can only be realized when studies evaluating the clinical and radiographic outcomes of cementless implants manufactured with additive manufacturing report durable fixation, less stress shielding, and better implant survivorship. Nevertheless, the authors believe that this technology holds great promise and may potentially change the conventional methods of casting, machining, and tooling for implant manufacturing in the future. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Development of a Regenerative Peripheral Nerve Interface for Control of a Neuroprosthetic Limb.

PubMed

Urbanchek, Melanie G; Kung, Theodore A; Frost, Christopher M; Martin, David C; Larkin, Lisa M; Wollstein, Adi; Cederna, Paul S

2016-01-01

Background. The purpose of this experiment was to develop a peripheral nerve interface using cultured myoblasts within a scaffold to provide a biologically stable interface while providing signal amplification for neuroprosthetic control and preventing neuroma formation. Methods. A Regenerative Peripheral Nerve Interface (RPNI) composed of a scaffold and cultured myoblasts was implanted on the end of a divided peroneal nerve in rats (n = 25). The scaffold material consisted of either silicone mesh, acellular muscle, or acellular muscle with chemically polymerized poly(3,4-ethylenedioxythiophene) conductive polymer. Average implantation time was 93 days. Electrophysiological tests were performed at endpoint to determine RPNI viability and ability to transduce neural signals. Tissue samples were examined using both light microscopy and immunohistochemistry. Results. All implanted RPNIs, regardless of scaffold type, remained viable and displayed robust vascularity. Electromyographic activity and stimulated compound muscle action potentials were successfully recorded from all RPNIs. Physiologic efferent motor action potentials were detected from RPNIs in response to sensory foot stimulation. Histology and transmission electron microscopy revealed mature muscle fibers, axonal regeneration without neuroma formation, neovascularization, and synaptogenesis. Desmin staining confirmed the preservation and maturation of myoblasts within the RPNIs. Conclusions. RPNI demonstrates significant myoblast maturation, innervation, and vascularization without neuroma formation.

Mechanical biocompatibility of highly deformable biomedical materials.

PubMed

Mazza, Edoardo; Ehret, Alexander E

2015-08-01

Mismatch of mechanical properties between highly deformable biomedical materials and adjacent native tissue might lead to short and long term health impairment. The capability of implants to deform at the right level, i.e. similar to the macroscopic mechanical response of the surrounding biological materials, is often associated with dissimilar microstructural deformation mechanisms. This mismatch on smaller length scales might lead to micro-injuries, cell damage, inflammation, fibrosis or necrosis. Hence, the mechanical biocompatibility of soft implants depends not only on the properties and composition of the implant material, but also on its organization, distribution and motion at one or several length scales. The challenges related to the analysis and attainment of mechanical biocompatibility are illustrated with two examples: prosthetic meshes for hernia and pelvic repair and electrospun scaffolds for tissue engineering. For these material systems we describe existing methods for characterization and analysis of the non-linear response to uniaxial and multiaxial stress states, its time and history dependence, and the changes in deformation behavior associated with tissue in-growth and material resorption. We discuss the multi-scale deformation behavior of biomaterials and adjacent tissue, and indicate major interdisciplinary questions to be addressed in future research. Copyright © 2015 Elsevier Ltd. All rights reserved.

Applications of Mesenchymal Stem Cells in Sinus Lift Augmentation as a Dental Implant Technology.

PubMed

Parnia, Feridoun; Yazdani, Javad; Maleki Dizaj, Solmaz

2018-01-01

The potential application of stem cell biology in human dentistry is a new and emerging field of research. The objective of the current review was to study the efficiency of mesenchymal stem cells (MSCs) in sinus lift augmentation (SLA). A literature review was performed in PubMed Central using MeSH keywords such as sinus lift, MSCs, dental implants, and augmentation. The searches involved full-text papers written in English, published in the past 10 years (2007-2017). The review included in vitro and in vivo studies on the use of MSCs in SLA. Electronic searching provided 45 titles, and among them, 8 papers were chosen as suitable based on the inclusion requirements of this review. The reviewed studies have revealed the potential of MSCs in SLA. According to these papers, stem cell therapy combined with different biomaterials may considerably improve bone regeneration in previous steps of dental implantation and may veritably lead to efficient clinical usages in the recent future. However, the identification of an ideal source of stem cells as well as long-term studies is vital to assess the success rate of this technology. Further clinical trials are also needed to approve the potential of MSCs in SLA.

Using "Rebar" to Stabilize Rigid Chest Wall Reconstruction.

PubMed

Robinson, Lary A; Grubbs, Deanna M

2016-04-01

After major chest wall resection, reconstruction of the bony defect with a rigid prosthesis is mandatory to protect the underlying thoracic organs, and to prevent flail chest physiology. Although many methods have been described for chest wall reconstruction, a commonly used technique employs a composite Marlex (polypropylene) mesh with methyl-methacrylate cement sandwiched between two layers of mesh (MMS), which is tailored to the defect size and shape. In building construction, steel "rebar" is used to strengthen and reinforce masonry structures. To avoid the initial residual motion of the rigid prosthesis used to reconstruct very large defects, particularly the sternum, we devised a simple technique of adding one or more Steinmann steel pins as "rebar" to strengthen and immediately stabilize the prosthesis to the surrounding ribs and sternum. For the very large defects, particularly over the heart and great vessels, titanium mesh may also be readily added into the sandwich construction for increased strength and to prevent late prosthetic fractures. Short- and long-term results of this inexpensive modification of the MMS reconstruction technique are excellent. This modified MMS tailor-made prosthesis is only one-third the cost of the recently popular prosthetic titanium systems, takes much less operative time to create and implant, and avoids the well-described complications of late titanium bar fracture and erosion/infection as well as loosening of screws and/or titanium bars. Georg Thieme Verlag KG Stuttgart · New York.

Effects of Structural Properties of Electrospun TiO2 Nano-fiber Meshes on their Osteogenic Potential

PubMed Central

Wang, Xiaokun; Gittens, Rolando A.; Song, Rosemary; Tannenbaum, Rina; Olivares-Navarrete, Rene; Schwartz, Zvi; Chen, Haifeng; Boyan, Barbara D.

2011-01-01

Ideal outcomes in the field of tissue engineering and regenerative medicine involve biomaterials that can enhance cell differentiation and production of local factors for natural tissue regeneration without the use of systemic drugs. Biomaterials typically used in tissue engineering applications include polymeric scaffolds that mimic the 3-D structural environment of the native tissue, but these are often functionalized with proteins or small peptides to improve their biological performance. For bone applications, titanium (Ti) implants, or more appropriately the titania (TiO2) passive oxide layer formed on their surface, have been shown to enhance osteoblast differentiation in vitro and to promote osseointegration in vivo. In this study we evaluated the effect on osteoblast differentiation of pure TiO2 nano-fiber meshes with different surface micro-roughness and nano-fiber diameters, prepared by the electrospinning method. MG63 cells were seeded on TiO2 meshes, and cell number, differentiation markers and local factor production were analyzed. The results showed that cells grew throughout the entire surfaces and with similar morphology in all groups. Cell number was sensitive to surface micro-roughness, whereas cell differentiation and local factor production was regulated by both surface roughness and nano-fiber diameter. These results indicate that scaffold structural cues alone can be used to drive cell differentiation and create an osteogenic environment without the use of exogenous factors. PMID:22075122

ELRIS2D: A MATLAB Package for the 2D Inversion of DC Resistivity/IP Data

NASA Astrophysics Data System (ADS)

Akca, Irfan

2016-04-01

ELRIS2D is an open source code written in MATLAB for the two-dimensional inversion of direct current resistivity (DCR) and time domain induced polarization (IP) data. The user interface of the program is designed for functionality and ease of use. All available settings of the program can be reached from the main window. The subsurface is discre-tized using a hybrid mesh generated by the combination of structured and unstructured meshes, which reduces the computational cost of the whole inversion procedure. The inversion routine is based on the smoothness constrained least squares method. In order to verify the program, responses of two test models and field data sets were inverted. The models inverted from the synthetic data sets are consistent with the original test models in both DC resistivity and IP cases. A field data set acquired in an archaeological site is also used for the verification of outcomes of the program in comparison with the excavation results.

Parameterizing unresolved obstacles with source terms in wave modeling: A real-world application

NASA Astrophysics Data System (ADS)

Mentaschi, Lorenzo; Kakoulaki, Georgia; Vousdoukas, Michalis; Voukouvalas, Evangelos; Feyen, Luc; Besio, Giovanni

2018-06-01

Parameterizing the dissipative effects of small, unresolved coastal features, is fundamental to improve the skills of wave models. The established technique to deal with this problem consists in reducing the amount of energy advected within the propagation scheme, and is currently available only for regular grids. To find a more general approach, Mentaschi et al., 2015b formulated a technique based on source terms, and validated it on synthetic case studies. This technique separates the parameterization of the unresolved features from the energy advection, and can therefore be applied to any numerical scheme and to any type of mesh. Here we developed an open-source library for the estimation of the transparency coefficients needed by this approach, from bathymetric data and for any type of mesh. The spectral wave model WAVEWATCH III was used to show that in a real-world domain, such as the Caribbean Sea, the proposed approach has skills comparable and sometimes better than the established propagation-based technique.

Newmark local time stepping on high-performance computing architectures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rietmann, Max, E-mail: max.rietmann@erdw.ethz.ch; Institute of Geophysics, ETH Zurich; Grote, Marcus, E-mail: marcus.grote@unibas.ch

In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strongmore » element-size contrasts (more than 100x). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.« less

Tissue Reinforcement in Implant-based Breast Reconstruction

PubMed Central

Scheflan, Michael

2014-01-01

Background: Tissue reinforcement with allogeneic or xenogeneic acellular dermal matrices (ADMs) is increasingly used in single-stage (direct-to-implant) and 2-stage implant-based breast reconstruction following mastectomy. ADMs allow surgeons to control implant position and obviate the need for submuscular implant placement. Here, we review the benefits and risks of using ADMs in implant-based breast reconstruction based on available data. Methods: A comprehensive analysis of the literature with focus on recent publications was performed. Additional information regarding the proper use of ADMs was based on our institutional experience. Results: ADM use may improve definition of the lateral confines of the breast and lower pole projection. It may facilitate direct-to-implant procedures and improve aesthetic outcomes. The effect of ADMs on complication rates remains controversial. Known patient risk factors such as obesity, smoking, and radiotherapy should be considered during patient selection. For patients with healthy, well-vascularized skin envelopes, ADM-assisted direct-to- implant reconstruction is a safe and cost-effective alternative to 2-stage implant reconstruction, with low complication rates. ADMs may be used to treat capsular contracture, and limited available data further suggest the possibility that ADMs may reduce the risk of capsular contracture. Novel synthetic or biosynthetic tissue reinforcement devices with different physical and ease-of-use properties than ADMs are emerging options for reconstructive surgeons and patients who seek to avoid tissue products from human or mammalian cadavers. Conclusions: ADM-assisted implant-based breast reconstruction may improve aesthetic outcomes. However, appropriate patient selection, surgical technique, and postoperative management are critical for its success, including minimizing the risk of complications. PMID:25426375

3D CSEM inversion based on goal-oriented adaptive finite element method

NASA Astrophysics Data System (ADS)

Zhang, Y.; Key, K.

2016-12-01

We present a parallel 3D frequency domain controlled-source electromagnetic inversion code name MARE3DEM. Non-linear inversion of observed data is performed with the Occam variant of regularized Gauss-Newton optimization. The forward operator is based on the goal-oriented finite element method that efficiently calculates the responses and sensitivity kernels in parallel using a data decomposition scheme where independent modeling tasks contain different frequencies and subsets of the transmitters and receivers. To accommodate complex 3D conductivity variation with high flexibility and precision, we adopt the dual-grid approach where the forward mesh conforms to the inversion parameter grid and is adaptively refined until the forward solution converges to the desired accuracy. This dual-grid approach is memory efficient, since the inverse parameter grid remains independent from fine meshing generated around the transmitter and receivers by the adaptive finite element method. Besides, the unstructured inverse mesh efficiently handles multiple scale structures and allows for fine-scale model parameters within the region of interest. Our mesh generation engine keeps track of the refinement hierarchy so that the map of conductivity and sensitivity kernel between the forward and inverse mesh is retained. We employ the adjoint-reciprocity method to calculate the sensitivity kernels which establish a linear relationship between changes in the conductivity model and changes in the modeled responses. Our code uses a direcy solver for the linear systems, so the adjoint problem is efficiently computed by re-using the factorization from the primary problem. Further computational efficiency and scalability is obtained in the regularized Gauss-Newton portion of the inversion using parallel dense matrix-matrix multiplication and matrix factorization routines implemented with the ScaLAPACK library. We show the scalability, reliability and the potential of the algorithm to deal with complex geological scenarios by applying it to the inversion of synthetic marine controlled source EM data generated for a complex 3D offshore model with significant seafloor topography.

European Hernia Society guidelines on prevention and treatment of parastomal hernias.

PubMed

Antoniou, S A; Agresta, F; Garcia Alamino, J M; Berger, D; Berrevoet, F; Brandsma, H-T; Bury, K; Conze, J; Cuccurullo, D; Dietz, U A; Fortelny, R H; Frei-Lanter, C; Hansson, B; Helgstrand, F; Hotouras, A; Jänes, A; Kroese, L F; Lambrecht, J R; Kyle-Leinhase, I; López-Cano, M; Maggiori, L; Mandalà, V; Miserez, M; Montgomery, A; Morales-Conde, S; Prudhomme, M; Rautio, T; Smart, N; Śmietański, M; Szczepkowski, M; Stabilini, C; Muysoms, F E

2018-02-01

International guidelines on the prevention and treatment of parastomal hernias are lacking. The European Hernia Society therefore implemented a Clinical Practice Guideline development project. The guidelines development group consisted of general, hernia and colorectal surgeons, a biostatistician and a biologist, from 14 European countries. These guidelines conformed to the AGREE II standards and the GRADE methodology. The databases of MEDLINE, CINAHL, CENTRAL and the gray literature through OpenGrey were searched. Quality assessment was performed using Scottish Intercollegiate Guidelines Network checklists. The guidelines were presented at the 38th European Hernia Society Congress and each key question was evaluated in a consensus voting of congress participants. End colostomy is associated with a higher incidence of parastomal hernia, compared to other types of stomas. Clinical examination is necessary for the diagnosis of parastomal hernia, whereas computed tomography scan or ultrasonography may be performed in cases of diagnostic uncertainty. Currently available classifications are not validated; however, we suggest the use of the European Hernia Society classification for uniform research reporting. There is insufficient evidence on the policy of watchful waiting, the route and location of stoma construction, and the size of the aperture. The use of a prophylactic synthetic non-absorbable mesh upon construction of an end colostomy is strongly recommended. No such recommendation can be made for other types of stomas at present. It is strongly recommended to avoid performing a suture repair for elective parastomal hernia. So far, there is no sufficient comparative evidence on specific techniques, open or laparoscopic surgery and specific mesh types. However, a mesh without a hole is suggested in preference to a keyhole mesh when laparoscopic repair is performed. An evidence-based approach to the diagnosis and management of parastomal hernias reveals the lack of evidence on several topics, which need to be addressed by multicenter trials. Parastomal hernia prevention using a prophylactic mesh for end colostomies reduces parastomal herniation. Clinical outcomes should be audited and adverse events must be reported.

Mesh fixation with glue versus suture for chronic pain and recurrence in Lichtenstein inguinal hernioplasty.

PubMed

Sun, Ping; Cheng, Xiang; Deng, Shichang; Hu, Qinggang; Sun, Yi; Zheng, Qichang

2017-02-07

Chronic pain following mesh-based inguinal hernia repair is frequently reported, and has a significant impact on quality of life. Whether mesh fixation with glue can reduce chronic pain without increasing the recurrence rate is still controversial. To determine whether tissue adhesives can reduce postoperative complications, especially chronic pain, with no increase in recurrence rate, compared with sutures for mesh fixation in Lichtenstein hernia repair. We searched the following electronic databases with no language restrictions: the Cochrane Central Register of Controlled Trials (CENTRAL; issue 4, 2016) in the Cochrane Library (searched 11 May 2016), MEDLINE Ovid (1986 to 11 May 2016), Embase Ovid (1986 to 11 May 2016), Science Citation Index (Web of Science) (1986 to 11 May 2016), CBM (Chinese Biomedical Database), CNKI (China National Knowledge Infrastructure), VIP (a full-text database in China), Wanfang databases. We also checked reference lists of identified papers (included studies and relevant reviews). We included all randomised and quasi-randomised controlled trials comparing glue versus sutures for mesh fixation in Lichtenstein hernia repair. Cluster-RCTs were also eligible. Two review authors extracted data and assessed the risk of bias independently. Dichotomous outcomes were expressed as odds ratio (OR) with 95% confidence intervals (CI). Continuous outcomes were expressed as mean differences (MD) with 95% CIs. Twelve trials with a total of 1932 participants were included in this review. The overall postoperative chronic pain in the glue group was reduced by 37% (OR 0.63, 95% CI 0.44 to 0.91; 10 studies, 1418 participants, low-quality evidence) compared with the suture group. However, the results changed when we conducted subgroup analysis with regard to the type of mesh. Subgroup analysis of included studies using lightweight mesh showed the reduction of chronic pain was less profound and insignificant (OR 0.77, 95% CI 0.50 to 1.17). Subgroup analysis of included studies using heavyweight mesh resulted in a significant benefit from the fixation with glue (OR 0.38, 95% CI 0.17 to 0.82).Hernia recurrence was similar between the two groups (OR 1.44, 95% CI 0.63 to 3.28; 12 studies, 1932 participants, low-quality evidence). Fixation with glue was superior to suture regarding duration of the operation (MD -3.13, 95% CI -4.48 to -1.78; 9 studies, 1790 participants, low-quality evidence); haematoma (OR 0.52, 95% CI 0.31 to 0.86; 10 studies, 1384 participants, moderate-quality evidence); and recovery time to daily activities (MD -1.26, 95% CI -1.89 to -0.63; 3 studies, 403 participants, low-quality evidence).We also investigated adverse events. There were no significant differences between the two groups. For superficial wound infection pooled analyses showed OR 1.23, 95% CI 0.37 to 4.11; 7 studies, 763 participants (low-quality evidence); for mesh/deep infection OR 0.67, 95% CI 0.16 to 2.83; 8 studies, 1393 participants (low-quality evidence). Furthermore, we investigated seroma (a postoperative swelling caused by fluid) (OR 0.83, 95% CI 0.51 to 1.33); and persisting numbness (OR 0.81, 95% CI 0.57 to 1.14).Finally, six trials involving 1009 participants reported postoperative length of stay, resulting in non-significant difference between the two groups (MD -0.12, 95% CI: -0.35 to 0.10)Due to the lack of data, it was impossible to draw any distinction between synthetic glue and biological glue.Eight out of 12 trials showed high risk of bias in at least one of the investigated domains. Two studies were quasi-randomised controlled trials and the allocation sequence of one trial was not concealed. Nearly half of the included trials either did not provide adequate information or had high risk of bias regarding blinding processes. The risk of bias for incomplete outcome data of all the included studies varied from low to high risk of bias. Two trials did not report on some important outcomes. One study was funded by the manufacturer producing the fibrin sealant. Therefore, according to the 'Summary of findings' tables, the quality of the evidence (GRADE) for the outcomes is moderate to low. Based on the short-term results, glue may reduce postoperative chronic pain and not simultaneously increase the recurrence rate, compared with sutures for mesh fixation in Lichtenstein hernia repair. Glue may therefore be a sensible alternative to suture for mesh fixation in Lichtenstein repair. Larger trials with longer follow-up and high quality are warranted. The difference between synthetic glue and biological glue should also be assessed in the future.

Three-Dimensional Bioprinting and Its Potential in the Field of Articular Cartilage Regeneration

PubMed Central

Mouser, Vivian H. M.; Levato, Riccardo; Bonassar, Lawrence J.; D’Lima, Darryl D.; Grande, Daniel A.; Klein, Travis J.; Saris, Daniel B. F.; Zenobi-Wong, Marcy; Gawlitta, Debby; Malda, Jos

2016-01-01

Three-dimensional (3D) bioprinting techniques can be used for the fabrication of personalized, regenerative constructs for tissue repair. The current article provides insight into the potential and opportunities of 3D bioprinting for the fabrication of cartilage regenerative constructs. Although 3D printing is already used in the orthopedic clinic, the shift toward 3D bioprinting has not yet occurred. We believe that this shift will provide an important step forward in the field of cartilage regeneration. Three-dimensional bioprinting techniques allow incorporation of cells and biological cues during the manufacturing process, to generate biologically active implants. The outer shape of the construct can be personalized based on clinical images of the patient’s defect. Additionally, by printing with multiple bio-inks, osteochondral or zonally organized constructs can be generated. Relevant mechanical properties can be obtained by hybrid printing with thermoplastic polymers and hydrogels, as well as by the incorporation of electrospun meshes in hydrogels. Finally, bioprinting techniques contribute to the automation of the implant production process, reducing the infection risk. To prompt the shift from nonliving implants toward living 3D bioprinted cartilage constructs in the clinic, some challenges need to be addressed. The bio-inks and required cartilage construct architecture need to be further optimized. The bio-ink and printing process need to meet the sterility requirements for implantation. Finally, standards are essential to ensure a reproducible quality of the 3D printed constructs. Once these challenges are addressed, 3D bioprinted living articular cartilage implants may find their way into daily clinical practice. PMID:28934880

Clinical effectiveness and cost-effectiveness of surgical options for the management of anterior and/or posterior vaginal wall prolapse: two randomised controlled trials within a comprehensive cohort study - results from the PROSPECT Study.

PubMed

Glazener, Cathryn; Breeman, Suzanne; Elders, Andrew; Hemming, Christine; Cooper, Kevin; Freeman, Robert; Smith, Anthony; Hagen, Suzanne; Montgomery, Isobel; Kilonzo, Mary; Boyers, Dwayne; McDonald, Alison; McPherson, Gladys; MacLennan, Graeme; Norrie, John

2016-12-01

The use of mesh in prolapse surgery is controversial, leading to a number of enquiries into its safety and efficacy. To compare synthetic non-absorbable mesh inlay, biological graft and mesh kit with a standard repair in terms of clinical effectiveness, adverse effects, quality of life (QoL), costs and cost-effectiveness. Two randomised controlled trials within a comprehensive cohort (CC) study. Allocation was by a remote web-based randomisation system in a 1 :1 : 1 ratio (Primary trial) or 1 : 1 : 2 ratio (Secondary trial), and was minimised on age, type of prolapse repair planned, need for a concomitant continence procedure, need for a concomitant upper vaginal prolapse procedure and surgeon. Participants and outcome assessors were blinded to randomisation; participants were unblinded if they requested the information. Surgeons were not blinded to allocated procedure. Thirty-five UK hospitals. Primary study : 2474 women in the analysis (including 1348 randomised) having primary anterior or posterior prolapse surgery. Secondary study : 398 in the analysis (including 154 randomised) having repeat anterior or posterior prolapse surgery. CC3 : 215 women having either uterine or vault prolapse repair. Anterior or posterior repair alone, or with mesh inlay, biological graft or mesh kit. Prolapse symptoms [Pelvic Organ Prolapse Symptom Score (POP-SS)]; prolapse-specific QoL; cost-effectiveness [incremental cost per quality-adjusted life-year (QALY)]. Primary trials : adjusting for baseline and minimisation covariates, mean POP-SS was similar for each comparison {standard 5.4 [standard deviation (SD) 5.5] vs. mesh 5.5 (SD 5.1), mean difference (MD) 0.00, 95% confidence interval (CI) -0.70 to 0.71; standard 5.5 (SD 5.6) vs. graft 5.6 (SD 5.6), MD -0.15, 95% CI -0.93 to 0.63}. Serious non-mesh adverse effects rates were similar between the groups in year 1 [standard 7.2% vs. mesh 7.8%, risk ratio (RR) 1.08, 95% CI 0.68 to 1.72; standard 6.3% vs. graft 9.8%, RR 1.57, 95% CI 0.95 to 2.59]. There were no statistically significant differences between groups in any other outcome measure. The cumulative mesh complication rates over 2 years were 2 of 430 (0.5%) for standard repair (trial 1), 46 of 435 (10.6%) for mesh inlay and 2 of 368 (0.5%) for biological graft. The CC findings were comparable. Incremental costs were £363 (95% CI -£32 to £758) and £565 (95% CI £180 to £950) for mesh and graft vs. standard, respectively. Incremental QALYs were 0.071 (95% CI -0.004 to 0.145) and 0.039 (95% CI -0.041 to 0.120) for mesh and graft vs. standard, respectively. A Markov decision model extrapolating trial results over 5 years showed standard repair had the highest probability of cost-effectiveness, but results were surrounded by considerable uncertainty. Secondary trials : there were no statistically significant differences between the randomised groups in any outcome measure, but the sample size was too small to be conclusive. The cumulative mesh complication rates over 2 years were 7 of 52 (13.5%) for mesh inlay and 4 of 46 (8.7%) for mesh kit, with no mesh exposures for standard repair. In women who were having primary repairs, there was evidence of no benefit from the use of mesh inlay or biological graft compared with standard repair in terms of efficacy, QoL or adverse effects (other than mesh complications) in the short term. The Secondary trials were too small to provide conclusive results. Women in the Primary trials included some with a previous repair in another compartment. Follow-up is vital to identify any long-term potential benefits and serious adverse effects. Long-term follow-up to at least 6 years after surgery is ongoing to identify recurrence rates, need for further prolapse surgery, adverse effects and cost-effectiveness. Current Controlled Trials ISRCTN60695184. This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 20, No. 95. See the NIHR Journals Library website for further project information.

The development of a composite bone model for training on placement of dental implants

PubMed Central

Alkhodary, Mohamed Ahmed; Abdelraheim, Abdelraheim Emad Eldin; Elsantawy, Abd Elaleem Hassan; Al Dahman, Yousef Hamad; Al-Mershed, Mohammed

2015-01-01

Objectives It takes a lot of training on patients for both undergraduate to develop clinical sense as regards to the placement of dental implants in the jaw bones, also, the models provided by the dental implant companies for training are usually made of strengthened synthetic foams, which are far from the composition, and tactile sense provided by natural bone during drilling for clinical placement of dental implants. Methodology This is an in-vitro experimental study which utilized bovine femur bone, where the shaft of the femur provided the surface compact layer, and the head provided the cancellous bone layer, to provide a training model similar to jaw bones macroscopic anatomy. Both the compact and cancellous bone samples were characterized using mechanical compressive testing. Results The elastic moduli of the cancellous and cortical femur bone were comparable to those of the human mandible, and the prepared training model provided a more lifelike condition during the drilling and placement of dental implants. Conclusion The composite bone model developed simulated the macroscopic anatomy of the jaw bones having a surface layer of compact bone, and a core of cancellous bone, and provided a better and a more natural hands-on experience for placement of dental implants as compared to plastic models made of polyurethane. PMID:26309434

The development of a composite bone model for training on placement of dental implants.

PubMed

Alkhodary, Mohamed Ahmed; Abdelraheim, Abdelraheim Emad Eldin; Elsantawy, Abd Elaleem Hassan; Al Dahman, Yousef Hamad; Al-Mershed, Mohammed

2015-04-01

It takes a lot of training on patients for both undergraduate to develop clinical sense as regards to the placement of dental implants in the jaw bones, also, the models provided by the dental implant companies for training are usually made of strengthened synthetic foams, which are far from the composition, and tactile sense provided by natural bone during drilling for clinical placement of dental implants. This is an in-vitro experimental study which utilized bovine femur bone, where the shaft of the femur provided the surface compact layer, and the head provided the cancellous bone layer, to provide a training model similar to jaw bones macroscopic anatomy. Both the compact and cancellous bone samples were characterized using mechanical compressive testing. The elastic moduli of the cancellous and cortical femur bone were comparable to those of the human mandible, and the prepared training model provided a more lifelike condition during the drilling and placement of dental implants. The composite bone model developed simulated the macroscopic anatomy of the jaw bones having a surface layer of compact bone, and a core of cancellous bone, and provided a better and a more natural hands-on experience for placement of dental implants as compared to plastic models made of polyurethane.

Osteotome-Mediated Sinus Lift without Grafting Material: A Review of Literature and a Technique Proposal

PubMed Central

Taschieri, Silvio; Corbella, Stefano; Saita, Massimo; Tsesis, Igor; Del Fabbro, Massimo

2012-01-01

Implant rehabilitation of the edentulous posterior maxilla may be a challenging procedure in the presence of insufficient bone volume for implant placement. Maxillary sinus augmentation with or without using grafting materials aims to provide adequate bone volume. The aim of the present study was to systematically review the existing literature on transalveolar maxillary sinus augmentation without grafting materials and to propose and describe an osteotome-mediated approach in postextraction sites in combination with platelet derivative. The systematic review showed that high implant survival rate (more than 96% after 5 years) can be achieved even without grafting the site, with a low rate of complications. Available alveolar bone height before surgery was not correlated to survival rate. In the described case report, three implants were placed in posterior maxilla after extraction of two teeth. An osteotome-mediated sinus lifting technique was performed with the use of platelet derivative (PRGF); a synthetic bone substitute was used to fill the gaps between implant and socket walls. No complications occurred, and implants were successfully in site after 1 year from prosthetic loading. The presented technique might represent a viable alternative for the treatment of edentulous posterior maxilla with atrophy of the alveolar bone though it needs to be validated by studies with a large sample size. PMID:22792108

Controlled-release systemic delivery - a new concept in cancer chemoprevention

PubMed Central

2012-01-01

Many chemopreventive agents have encountered bioavailability issues in pre-clinical/clinical studies despite high oral doses. We report here a new concept utilizing polycaprolactone implants embedded with test compounds to obtain controlled systemic delivery, circumventing oral bioavailability issues and reducing the total administered dose. Compounds were released from the implants in vitro dose dependently and for long durations (months), which correlated with in vivo release. Polymeric implants of curcumin significantly inhibited tissue DNA adducts following the treatment of rats with benzo[a]pyrene, with the total administered dose being substantially lower than typical oral doses. A comparison of bioavailability of curcumin given by implants showed significantly higher levels of curcumin in the plasma, liver and brain 30 days after treatment compared with the dietary route. Withaferin A implants resulted in a nearly 60% inhibition of lung cancer A549 cell xenografts, but no inhibition occurred when the same total dose was administered intraperitoneally. More than 15 phytochemicals have been tested successfully by this formulation. Together, our data indicate that this novel implant-delivery system circumvents oral bioavailability issues, provides continuous delivery for long durations and lowers the total administered dose, eliciting both chemopreventive/chemotherapeutic activities. This would also allow the assessment of activity of minor constituents and synthetic metabolites, which otherwise remain uninvestigated in vivo. PMID:22696595

[Current requirements for polymeric biomaterials in ear, nose and throat medicine].

PubMed

Sternberg, K

2009-05-01

In recent years the ear, nose and throat medicine (ENT medicine) has been stimulated by numerous innovations in the field of implants which are based on new biomaterials and modern implant technologies. In this context, biomaterials integrated in living organisms have to allow for the technical requirements and the biological interactions between the implant and the tissue. With regard to their suitability, functional capability of the implant, which is complementary to the mechanical implant properties, sufficient stability against physiological media, as well as high biocompatibility are to be demanded. Another purpose of the use of biomaterials is the maintenance and the enhancement of biofunctionality over a long time period. These general requirements for biomaterials also have their validity in ENT medicine. Different materials are applied as biomaterials. Metals belong to the oldest biomaterials. In addition, alloys, ceramics, inorganic glasses and composites were tested. Furthermore, natural and synthetic polymers, which are primarily presented in this article regarding their properties and their applications as materials for cochlear implants, osteosynthesis implants, stents and novel scaffolds for tissue engineering, are increasingly applied. According to their use in permanent and temporary implants, polymers are to be differentiated between biostable and biodegradable polymers. The presented general and current requirements for biomaterials and biomaterial applications in ENT medicine demonstrate key aspects of the current biomaterial research in this field. They do as well document the high impact of the interdisciplinary collaboration of natural and medical scientists and engineers.

Robust adaptive 3-D segmentation of vessel laminae from fluorescence confocal microscope images and parallel GPU implementation.

PubMed

Narayanaswamy, Arunachalam; Dwarakapuram, Saritha; Bjornsson, Christopher S; Cutler, Barbara M; Shain, William; Roysam, Badrinath

2010-03-01

This paper presents robust 3-D algorithms to segment vasculature that is imaged by labeling laminae, rather than the lumenal volume. The signal is weak, sparse, noisy, nonuniform, low-contrast, and exhibits gaps and spectral artifacts, so adaptive thresholding and Hessian filtering based methods are not effective. The structure deviates from a tubular geometry, so tracing algorithms are not effective. We propose a four step approach. The first step detects candidate voxels using a robust hypothesis test based on a model that assumes Poisson noise and locally planar geometry. The second step performs an adaptive region growth to extract weakly labeled and fine vessels while rejecting spectral artifacts. To enable interactive visualization and estimation of features such as statistical confidence, local curvature, local thickness, and local normal, we perform the third step. In the third step, we construct an accurate mesh representation using marching tetrahedra, volume-preserving smoothing, and adaptive decimation algorithms. To enable topological analysis and efficient validation, we describe a method to estimate vessel centerlines using a ray casting and vote accumulation algorithm which forms the final step of our algorithm. Our algorithm lends itself to parallel processing, and yielded an 8 x speedup on a graphics processor (GPU). On synthetic data, our meshes had average error per face (EPF) values of (0.1-1.6) voxels per mesh face for peak signal-to-noise ratios from (110-28 dB). Separately, the error from decimating the mesh to less than 1% of its original size, the EPF was less than 1 voxel/face. When validated on real datasets, the average recall and precision values were found to be 94.66% and 94.84%, respectively.

The ADER-DG method for seismic wave propagation and earthquake rupture dynamics

NASA Astrophysics Data System (ADS)

Pelties, Christian; Gabriel, Alice; Ampuero, Jean-Paul; de la Puente, Josep; Käser, Martin

2013-04-01

We will present the Arbitrary high-order DERivatives Discontinuous Galerkin (ADER-DG) method for solving the combined elastodynamic wave propagation and dynamic rupture problem. The ADER-DG method enables high-order accuracy in space and time while being implemented on unstructured tetrahedral meshes. A tetrahedral element discretization provides rapid and automatized mesh generation as well as geometrical flexibility. Features as mesh coarsening and local time stepping schemes can be applied to reduce computational efforts without introducing numerical artifacts. The method is well suited for parallelization and large scale high-performance computing since only directly neighboring elements exchange information via numerical fluxes. The concept of fluxes is a key ingredient of the numerical scheme as it governs the numerical dispersion and diffusion properties and allows to accommodate for boundary conditions, empirical friction laws of dynamic rupture processes, or the combination of different element types and non-conforming mesh transitions. After introducing fault dynamics into the ADER-DG framework, we will demonstrate its specific advantages in benchmarking test scenarios provided by the SCEC/USGS Spontaneous Rupture Code Verification Exercise. An important result of the benchmark is that the ADER-DG method avoids spurious high-frequency contributions in the slip rate spectra and therefore does not require artificial Kelvin-Voigt damping, filtering or other modifications of the produced synthetic seismograms. To demonstrate the capabilities of the proposed scheme we simulate an earthquake scenario, inspired by the 1992 Landers earthquake, that includes branching and curved fault segments. Furthermore, topography is respected in the discretized model to capture the surface waves correctly. The advanced geometrical flexibility combined with an enhanced accuracy will make the ADER-DG method a useful tool to study earthquake dynamics on complex fault systems in realistic rheologies.