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Sample records for polymer nerve guides

  1. A polymer foam conduit seeded with Schwann cells promotes guided peripheral nerve regeneration.

    PubMed

    Hadlock, T; Sundback, C; Hunter, D; Cheney, M; Vacanti, J P

    2000-04-01

    Alternatives to autografts have long been sought for use in bridging neural gaps. Many entubulation materials have been studied, although with generally disappointing results in comparison with autografts. The purpose of this study was to design a more effective neural guidance conduit, to introduce Schwann cells into the conduit, and to determine regenerative capability through it in an in vivo model. A novel, fully biodegradable polymer conduit was designed and fabricated for use in peripheral nerve repair, which approximates the macro- and microarchitecture of native peripheral nerves. It comprised a series of longitudinally aligned channels, with diameters ranging from 60 to 550 microns. The lumenal surfaces promoted the adherence of Schwann cells, whose presence is known to play a key role in nerve regeneration. This unique channel architecture increased the surface area available for Schwann cell adherence up to five-fold over that available through a simple hollow conduit. The conduit was composed of a high-molecular-weight copolymer of lactic and glycolic acids (PLGA) (MW 130,000) in an 85:15 monomer ratio. A novel foam-processing technique, employing low-pressure injection molding, was used to create highly porous conduits (approximately 90% pore volume) with continuous longitudinal channels. Using this technique, conduits were constructed containing 1, 5, 16, 45, or more longitudinally aligned channels. Prior to cellular seeding of these conduits, the foams were prewet with 50% ethanol, flushed with physiologic saline, and coated with laminin solution (10 microg/mL). A Schwann cell suspension was dynamically introduced into these processed foams at a concentration of 5 X 10(5) cells/mL, using a simple bioreactor flow loop. In vivo regeneration studies were carried out in which cell-laden five-channel polymer conduits (individual channel ID 500 microm, total conduit OD 2.3 mm) were implanted across a 7-mm gap in the rat sciatic nerve (n = 4), and midgraft

  2. Evaluation of biodegradable polymer conduits--poly(L-lactic acid)--for guiding sciatic nerve regeneration in mice.

    PubMed

    Goulart, Camila Oliveira; Lopes, Fátima Rosalina Pereira; Monte, Zulmira Oliveira; Dantas, Severino Valentim; Souto, Allana; Oliveira, Júlia Teixeira; Almeida, Fernanda Martins; Tonda-Turo, Chiara; Pereira, Cristina Cardoso; Borges, Cristiano Piacsek; Martinez, Ana Maria Blanco

    2016-04-15

    Polymeric biomaterials are often used for stimulating nerve regeneration. Among different conduits, poly(lactide acid) - PLA polymer is considered to be a good substrate due to its biocompatibility and resorbable characteristics. This polymer is an aliphatic polyester which has been mostly used in biomedical application. It is an organic compound with low allergenic potential, low toxicity, high biocompatibility and predictable kinetics of degradation. In this study we fabricated and evaluated a PLA microporous hollow fiber as a conduit for its ability to bridge a nerve gap in a mouse sciatic nerve injury model. The PLA conduit was prepared from a polymer solution, throughout extrusion technique. The left sciatic nerve of C57BL/6 mouse was transected and the nerve stumps were placed into a resorbable PLA (PLA group) or a PCL conduit (PCL group), n=5 each group. We have also used another group in which the nerves were repaired by autograft (autograft group, n=5). Motor function was analyzed according to sciatic functional index (SFI). After 56days, the regenerated nerves were processed for light and electron microscopy and morphometric analyses were performed. A quantitative analysis of regenerated nerves showed significant increase in the number of myelinated fibers and blood vessels in animals that received PLA conduit. The PLA group exhibited better overall tissue organization compared to other groups. Presenting well-organized bundles, many regenerating clusters composed of preserved nerve fibers surrounded by layers of compacted perineurium-like cells. Also the SFI revealed a significant improvement in functional recovery. This work suggests that PLA conduits are suitable substrate for cell survival and it provides an effective strategy to be used to support axonal growth becoming a potential alternative to autograft.

  3. Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration

    DTIC Science & Technology

    2015-01-01

    guide conduits (NGCs) made of biodegradable materials offer a potential solution to this problem. Based on our previous accomplishments in developing...completed Task 2 and finalized the design of the nerve conduits. Optimizing Nanofiber Guidance (tasks 2a-2d) Final Composition of the Optimized NGC...WL, Cui FZ, Korgel BA, Gerecht S, Mao HQ. Creating polymer hydrogel microfibres with internal alignment via electrical and mechanical stretching

  4. Study of a (trimethylenecarbonate-co-epsilon-caprolactone) polymer part 1: preparation of a new nerve guide through controlled random copolymerization using rare earth catalysts.

    PubMed

    Schappacher, M; Fabre, T; Mingotaud, A F; Soum, A

    2001-11-01

    Random copolymers of trimethylene carbonate and epsilon-caprolactone have been synthesized through ring-opening polymerization using rare earth alkoxides as initiator. The structure of the copolymers has been characterized by 1H and 13C NMR. Their thermal behaviour, their permeability to liquid and their mechanical properties have also been evaluated. These copolymers have been used to process a new nerve guide.

  5. Multifunctional Silk Nerve Guides for Axon Outgrowth

    NASA Astrophysics Data System (ADS)

    Tupaj, Marie C.

    Peripheral nerve regeneration is a critical issue as 2.8% of trauma patients present with this type of injury, estimating a total of 200,000 nerve repair procedures yearly in the United States. While the peripheral nervous system exhibits slow regeneration, at a rate of 0.5 mm -- 9 mm/day following trauma, this regenerative ability is only possible under certain conditions. Clinical repairs have changed slightly in the last 30 years and standard methods of treatment include suturing damaged nerve ends, allografting, and autografting, with the autograft the gold standard of these approaches. Unfortunately, the use of autografts requires a second surgery and there is a shortage of nerves available for grafting. Allografts are a second option however allografts have lower success rates and are accompanied by the need of immunosuppressant drugs. Recently there has been a focus on developing nerve guides as an "off the shelf" approach. Although some natural and synthetic guidance channels have been approved by the FDA, these nerve guides are unfunctionalized and repair only short gaps, less than 3 cm in length. The goal of this project was to identify strategies for functionalizing peripheral nerve conduits for the outgrowth of neuron axons in vitro . To accomplish this, two strategies (bioelectrical and biophysical) were indentified for increasing axon outgrowth and promoting axon guidance. Bioelectrical strategies exploited electrical stimulation for increasing neurite outgrowth. Biophysical strategies tested a range of surface topographies for axon guidance. Novel methods were developed for integrating electrical and biophysical strategies into silk films in 2D. Finally, a functionalized nerve conduit system was developed that integrated all strategies for the purpose of attaching, elongating, and guiding nervous tissue in vitro. Future directions of this work include silk conduit translation into a rat sciatic nerve model in vivo for the purpose of repairing long

  6. Polymer scaffolds with preferential parallel grooves enhance nerve regeneration.

    PubMed

    Mobasseri, Atefeh; Faroni, Alessandro; Minogue, Ben M; Downes, Sandra; Terenghi, Giorgio; Reid, Adam J

    2015-03-01

    We have modified the surface topography of poly ɛ-caprolactone (PCL) and polylactic acid (PLA) blended films to improve cell proliferation and to guide the regeneration of peripheral nerves. Films with differing shaped grooves were made using patterned silicon templates, sloped walls (SL), V-shaped (V), and square-shaped (SQ), and compared with nongrooved surfaces with micropits. The solvent cast films were tested in vitro using adult adipose-derived stem cells differentiated to Schwann cell-like cells. Cell attachment, proliferation, and cell orientation were all improved on the grooved surfaces, with SL grooves giving the best results. We present in vivo data on Sprague-Dawley rat sciatic nerve injury with a 10-mm gap, evaluating nerve regeneration at 3 weeks across a polymer nerve conduit modified with intraluminal grooves (SL, V, and SQ) and differing wall thicknesses (70, 100, 120, and 210 μm). The SL-grooved nerve conduit showed a significant improvement over the other topographical-shaped grooves, while increasing the conduit wall thickness saw no positive effect on the biological response of the regenerating nerve. Furthermore, the preferred SL-grooved conduit (C) with 70 μm wall thickness was compared with the current clinical gold standard of autologous nerve graft (Ag) in the rat 10-mm sciatic nerve gap model. At 3 weeks postsurgery, all nerve gaps across both groups were bridged with regenerated nerve fibers. At 16 weeks, features of regenerated axons were comparable between the autograft (Ag) and conduit (C) groups. End organ assessments of muscle weight, electromyography, and skin reinnervation were also similar between the groups. The comparable experimental outcome between conduit and autograft, suggests that the PCL/PLA conduit with inner lumen microstructured grooves could be used as a potential alternative treatment for peripheral nerve repair.

  7. Functional gait evaluation of collagen chitosan nerve guides for sciatic nerve repair.

    PubMed

    Patel, Minal; Vandevord, Pamela J; Matthew, Howard W; Desilva, Stephen; Wu, Bin; Wooley, Paul H

    2008-12-01

    The objective of this work was to use a functional gait analysis technique to evaluate sciatic nerve repair through tissue-engineered nerve guides in a rodent animal model. The nerve guides were fabricated by blending collagen with chitosan material and evaluated over a 12-week period for motor and sensory nerve recovery assessed by gait analysis and behavioral testing. Gastrocnemius muscle weight measurements were obtained at the end of each experimental time point and correlated to motor nerve recovery. Functional gait analysis studied both the stance and swing phase angle formations during a normal gait cycle. During the stance phase, functional results revealed that blended nerve guides promoted increased motor nerve recovery than unblended chitosan nerve guides. Similar results were obtained from behavioral tests, indicating that blended nerve guides created increased sensitivity to applied stimulus compared to unblended nerve guides. Muscle strength also correlated with functional recovery and was significantly higher when compared to the unblended nerve guides. From this study, we conclude that collagen-blended chitosan nerve guides enhanced motor and sensory nerve recovery assayed through gait and behavioral testing compared to unblended nerve guides.

  8. Polymeric biomaterials for nerve regeneration: fabrication and implantation of a biodegradable nerve guide.

    PubMed

    Sivak, Wesley N; Bliley, Jacqueline M; Marra, Kacey G

    2014-01-01

    Optimizing the quantity, quality, and speed of axon regeneration is important in maximizing functional outcomes following peripheral nerve injury. When severed, injured nerves must be able to regenerate and reconnect to the structures they previously controlled within 12-18 months before sensation and motion are permanently lost. Nerve sprouts from the proximal stump will spontaneously migrate toward the distal stump in the event of a nerve transection. However, surgical intervention remains necessary to repair transection injuries. Regeneration becomes particularly troublesome with large gaps, where autologous nerve grafts or nerve guides are used to repair transected nerves. Nerve conduits function as therapeutic adjuncts, guiding axonal regeneration across gap defects. Despite the availability of several FDA-approved nerve conduits, functional outcomes following their use remain less than optimal. Much work has been focused on developing nerve conduits to improve peripheral nerve repair outcomes. This chapter describes fabrication of a poly(caprolactone) nerve guide and demonstrates its use in a rat sciatic nerve model.

  9. Recent Strategies in Tissue Engineering for Guided Peripheral Nerve Regeneration.

    PubMed

    Belanger, Kayla; Dinis, Tony M; Taourirt, Sami; Vidal, Guillaume; Kaplan, David L; Egles, Christopher

    2016-04-01

    The repair of large crushed or sectioned segments of peripheral nerves remains a challenge in regenerative medicine due to the complexity of the biological environment and the lack of proper biomaterials and architecture to foster reconstruction. Traditionally such reconstruction is only achieved by using fresh human tissue as a surrogate for the absence of the nerve. However, recent focus in the field has been on new polymer structures and specific biofunctionalization to achieve the goal of peripheral nerve regeneration by developing artificial nerve prostheses. This review presents various tested approaches as well their effectiveness for nerve regrowth and functional recovery.

  10. [The preparation and evaluation of tissue inducible nerve guide conduit].

    PubMed

    Zhao, Hongbin; Liu, Xingyan; Ge, Baofeng; Guo, Chao; Zhen, Ping

    2012-04-01

    The objective of this research was to fabricate a novel tissue inducible nerve guide conduit, and to evaluate its biologic property. The microspheres were prepared with chitosan that encapsulated ligustrazine. The drug release of the chitosan microspheres was detected with application of the controlled release method in vitro. Chitosan microspheres were mixed with collagen to fabricate the tissue inducible nerve conduit, which were crosslinked with 2% genipin for 24h. Mechanical properties of the nerve guide conduit samples, including maximum load and breaking load, were measured using an Instron Series IX Automated Materials Testing System. The flexibility of the nerve guide conduit was determined with the texture evaluation instrument. Different methods, such as scanning electron microscope (SEM), light microscope (LMS) and immunofluorescence were used to analyze the spatial structure of the nerve guide conduit, the distribution of the microspheres, the state of the nerve duct combined with mesenchymal stem cells (MSCs), and the effect of the ligustrazine that released from chitosan microsphere on MSCs differentiation into nerve cells, respectively. The results showed that the chitosan microspheres had better releasing effect. The mechanical properties resultant nerve guide conduit were determined. The maximum load and breaking load of the genipin crosslinked samples were significantly higher than that observed with the non-crosslinkers, increasing to (0.76 +/- 0.15) N and (0.69 +/- 0.17) N from (0.23 +/- 0.09) N and (0.20 +/- 0.12) N for the non-crosslinkers (P < 0.01). The degradation rates of non-crosslinked and crosslinked by genipin were(58.62 +/- 7.59) mg and (9.23 +/- 2.47) mg, respec- tively. This had a statistical significance (P < 0.01). The average linearities in dry and hygrometric state of the nerve guide conduit were (0.597 +/- 0.012) LC and (0.333 +/- 0.015) LC, respectively, which also had statistical significance (P < 0.01). The flexibility in

  11. Neuroprotective effects of ultrasound-guided nerve growth factor injections after sciatic nerve injury

    PubMed Central

    Li, Hong-fei; Wang, Yi-ru; Huo, Hui-ping; Wang, Yue-xiang; Tang, Jie

    2015-01-01

    Nerve growth factor (NGF) plays an important role in promoting neuroregeneration after peripheral nerve injury. However, its effects are limited by its short half-life; it is therefore important to identify an effective mode of administration. High-frequency ultrasound (HFU) is increasingly used in the clinic for high-resolution visualization of tissues, and has been proposed as a method for identifying and evaluating peripheral nerve damage after injury. In addition, HFU is widely used for guiding needle placement when administering drugs to a specific site. We hypothesized that HFU guiding would optimize the neuroprotective effects of NGF on sciatic nerve injury in the rabbit. We performed behavioral, ultrasound, electrophysiological, histological, and immunohistochemical evaluation of HFU-guided NGF injections administered immediately after injury, or 14 days later, and compared this mode of administration with intramuscular NGF injections. Across all assessments, HFU-guided NGF injections gave consistently better outcomes than intramuscular NGF injections administered immediately or 14 days after injury, with immediate treatment also yielding better structural and functional results than when the treatment was delayed by 14 days. Our findings indicate that NGF should be administered as early as possible after peripheral nerve injury, and highlight the striking neuroprotective effects of HFU-guided NGF injections on peripheral nerve injury compared with intramuscular administration. PMID:26807123

  12. Neuroprotective effects of ultrasound-guided nerve growth factor injections after sciatic nerve injury.

    PubMed

    Li, Hong-Fei; Wang, Yi-Ru; Huo, Hui-Ping; Wang, Yue-Xiang; Tang, Jie

    2015-11-01

    Nerve growth factor (NGF) plays an important role in promoting neuroregeneration after peripheral nerve injury. However, its effects are limited by its short half-life; it is therefore important to identify an effective mode of administration. High-frequency ultrasound (HFU) is increasingly used in the clinic for high-resolution visualization of tissues, and has been proposed as a method for identifying and evaluating peripheral nerve damage after injury. In addition, HFU is widely used for guiding needle placement when administering drugs to a specific site. We hypothesized that HFU guiding would optimize the neuroprotective effects of NGF on sciatic nerve injury in the rabbit. We performed behavioral, ultrasound, electrophysiological, histological, and immunohistochemical evaluation of HFU-guided NGF injections administered immediately after injury, or 14 days later, and compared this mode of administration with intramuscular NGF injections. Across all assessments, HFU-guided NGF injections gave consistently better outcomes than intramuscular NGF injections administered immediately or 14 days after injury, with immediate treatment also yielding better structural and functional results than when the treatment was delayed by 14 days. Our findings indicate that NGF should be administered as early as possible after peripheral nerve injury, and highlight the striking neuroprotective effects of HFU-guided NGF injections on peripheral nerve injury compared with intramuscular administration.

  13. Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration

    DTIC Science & Technology

    2014-01-01

    months 24-33) 3d. Retrograde labeling and tissue harvesting (months 32-33) 3e. Nerve morphometry (months 33-35) 3f. Histopathological evaluations...divided into specific tasks related to various components of optimization schemes. In vitro fiber size dependent Schwann cell migration for...5/7/13 17 4 S(design medium 1200 0 Uniform 6/27/13 Tier(5 18 4 S(Design medium 1200 0 Shallow(Gradient(60L180 6/28/13 19 8 S(Design medium 1200 0

  14. Types of neural guides and using nanotechnology for peripheral nerve reconstruction

    PubMed Central

    Biazar, Esmaeil; Khorasani, MT; Montazeri, Naser; Pourshamsian, Khalil; Daliri, Morteza; T, Mostafa Rezaei; B, Mahmoud Jabarvand; Khoshzaban, Ahad; K, Saeed Heidari; Jafarpour, Mostafa; Roviemiab, Ziba

    2010-01-01

    Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Different methods, such as conventional allograft procedures and use of biologic tubes present problems when used for damaged peripheral nerve reconstruction. Designed scaffolds comprised of natural and synthetic materials are now widely used in the reconstruction of damaged tissues. Utilization of absorbable and nonabsorbable synthetic and natural polymers with unique characteristics can be an appropriate solution to repair damaged nerve tissues. Polymeric nanofibrous scaffolds with properties similar to neural structures can be more effective in the reconstruction process. Better cell adhesion and migration, more guiding of axons, and structural features, such as porosity, provide a clearer role for nanofibers in the restoration of neural tissues. In this paper, basic concepts of peripheral nerve injury, types of artificial and natural guides, and methods to improve the performance of tubes, such as orientation, nanotechnology applications for nerve reconstruction, fibers and nanofibers, electrospinning methods, and their application in peripheral nerve reconstruction are reviewed. PMID:21042546

  15. Biomimetic Micropatterned Multi-channel Nerve Guides by Templated Electrospinning

    PubMed Central

    Jeffries, Eric; Wang, Yadong

    2012-01-01

    This report describes a new approach for fabricating micro-channels within three-dimensional electrospun constructs. These key features serve to mimic the fascicular architecture and fibrous extracellular matrix found in native nerve. Both electrospun fibers and multi-channeled structure nerve guides have become areas of increasing interest for their beneficial roles in nerve repair. However, to the best of our knowledge, this is the first report of a guide that incorporates both. Multiple parallel channels provide a greater number of defined paths and increased surface area compared to cylindrical guides. Additionally, the fibrous nature of electrospun fibers permits better mass transport than solid-walled constructs. The flexible fabrication scheme allows tailoring of nerve guide parameters such as channel diameters ranging from 33-176μm and various wall thicknesses. Channel and fiber structures were assessed by optical and electron microscope images. Geometric calculations estimated a porosity of over 85% for these guides with 16% or less from the channels. In vitro culture with Schwann cells demonstrated cellular infiltration into channels with restricted migration between fibers. Finally, cell proliferation and survival throughout the guide indicates that this design warrants future in vivo examination. PMID:22179932

  16. Nerve Stimulator versus Ultrasound-Guided Femoral Nerve Block; a Randomized Clinical Trial

    PubMed Central

    Forouzan, Arash; Masoumi, Kambiz; Motamed, Hasan; Gousheh, Mohammad Reza; Rohani, Akram

    2017-01-01

    Introduction: Pain control is the most important issue in emergency department management of patients with femoral bone fractures. The present study aimed to compare the procedural features of ultrasonography and nerve stimulator guided femoral nerve block in this regard. Method: In this randomized clinical trial, patients with proximal femoral fractures presenting to emergency department were randomly divided into two groups of ultrasonography or nerve stimulator guided femoral block and compared regarding success rate, procedural time, block time, and need for rescue doses of morphine sulfate, using SPSS 20. Results: 50 patients were randomly divided into two groups of 25 (60% male). The mean age of studied patients was 35.14 ± 12.95 years (19 – 69). The two groups were similar regarding age (p= 0.788), sex (p = 0.564), and initial pain severity (p = 0.513). In 2 cases of nerve stimulator guided block, loss of pinprick sensation did not happen within 30 minutes of injection (success rate: 92%; p = 0.490). Ultrasonography guided nerve block cases had significantly lower procedural time (8.06 ± 1.92 vs 13.60 ± 4.56 minutes; p < 0.001) and lower need for rescue doses of opioid (2.68 ± 0.74 vs 5.28 ± 1.88 minutes; p < 0.001). Conclusion: Ultrasonography and nerve stimulator guided femoral block had the same success rate and block duration. However, the ultrasonography guided group had lower procedure time and lower need for rescue doses of morphine sulfate. Therefore, ultrasonography guided femoral block could be considered as an available, safe, rapid, and efficient method for pain management of femoral fracture in emergency department.

  17. Ultrasound-Guided Lateral Femoral Cutaneous Nerve Conduction Study

    PubMed Central

    Park, Bum Jun; Joeng, Eui Soo; Choi, Jun Kyu; Kang, Seok; Yoon, Joon Shik

    2015-01-01

    Objective To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique. Methods Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques. Results Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 µV and 6.66±0.54 µV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique. Conclusion Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude. PMID:25750871

  18. Ultrasound-guided percutaneous injection of methylene blue to identify nerve pathology and guide surgery.

    PubMed

    Osorio, Joseph A; Breshears, Jonathan D; Arnaout, Omar; Simon, Neil G; Hastings-Robinson, Ashley M; Aleshi, Pedram; Kliot, Michel

    2015-09-01

    OBJECT The objective of this study was to provide a technique that could be used in the preoperative period to facilitate the surgical exploration of peripheral nerve pathology. METHODS The authors describe a technique in which 1) ultrasonography is used in the immediate preoperative period to identify target peripheral nerves, 2) an ultrasound-guided needle electrode is used to stimulate peripheral nerves to confirm their position, and then 3) a methylene blue (MB) injection is performed to mark the peripheral nerve pathology to facilitate surgical exploration. RESULTS A cohort of 13 patients with varying indications for peripheral nerve surgery is presented in which ultrasound guidance, stimulation, and MB were used to localize and create a road map for surgeries. CONCLUSIONS Preoperative ultrasound-guided MB administration is a promising technique that peripheral nerve surgeons could use to plan and execute surgery.

  19. Peripheral Nerve Regeneration Strategies: Electrically Stimulating Polymer Based Nerve Growth Conduits

    PubMed Central

    Anderson, Matthew; Shelke, Namdev B.; Manoukian, Ohan S.; Yu, Xiaojun; McCullough, Louise D.; Kumbar, Sangamesh G.

    2017-01-01

    Treatment of large peripheral nerve damages ranges from the use of an autologous nerve graft to a synthetic nerve growth conduit. Biological grafts, in spite of many merits, show several limitations in terms of availability and donor site morbidity, and outcomes are suboptimal due to fascicle mismatch, scarring, and fibrosis. Tissue engineered nerve graft substitutes utilize polymeric conduits in conjunction with cues both chemical and physical, cells alone and or in combination. The chemical and physical cues delivered through polymeric conduits play an important role and drive tissue regeneration. Electrical stimulation (ES) has been applied toward the repair and regeneration of various tissues such as muscle, tendon, nerve, and articular tissue both in laboratory and clinical settings. The underlying mechanisms that regulate cellular activities such as cell adhesion, proliferation, cell migration, protein production, and tissue regeneration following ES is not fully understood. Polymeric constructs that can carry the electrical stimulation along the length of the scaffold have been developed and characterized for possible nerve regeneration applications. We discuss the use of electrically conductive polymers and associated cell interaction, biocompatibility, tissue regeneration, and recent basic research for nerve regeneration. In conclusion, a multifunctional combinatorial device comprised of biomaterial, structural, functional, cellular, and molecular aspects may be the best way forward for effective peripheral nerve regeneration. PMID:27278739

  20. Manufacture of porous polymer nerve conduits through a lyophilizing and wire-heating process.

    PubMed

    Huang, Yi-Cheng; Huang, Yi-You; Huang, Chun-Chieh; Liu, Hwa-Chang

    2005-07-01

    We have developed a method for nerve tissue regeneration using longitudinally oriented channels within biodegradable polymers created by a combined lyophilizing and wire-heating process. This type of cell-adhesive scaffold provides increased area to support and guide extending axons subsequent to nerve injury. Utilizing Ni-Cr wires as mandrels to create channels in scaffold increased safety, effectiveness, and reproducibility. The scaffolds tested were made from different biodegradable polymers, chitosan and poly(D,L-lactide-co-glycolide) (PLGA), because of their availability, ease of processing, low inflammatory response, and approval by the FDA. According to our experimental results, the high permeability and the characteristic porous structure of chitosan proved to be a better material for nerve guidance than PLGA. The scanning electron micrographs revealed that the scaffolds were consistent along the longitudinal axis with channels being distributed evenly throughout the scaffolds. There was no evidence to suggest merging or splitting of individual channels. The diameter of the channels was about 100 mum, similar to the 115 micromameter of the Ni-Cr wire. Regulating the size and quantity of the Ni-Cr wires allow us to control the number and the diameter of the channels. Furthermore, the neutralizing processes significantly influenced the porous structure of chitosan scaffolds. Using weak base (NaHCO(3) 1M) to neutralize chitosan scaffolds made the porous structure more uniform. The innovative method of using Ni-Cr wires as mandrels could be easily tailored to other polymer and solvent systems. The high permeability and the characteristic porous structure of chitosan made it a superior material for nerve tissue engineering. These scaffolds could be useful for guiding regeneration of the peripheral nerve or spinal cord after a transection injury.

  1. Effect of surface pore structure of nerve guide conduit on peripheral nerve regeneration.

    PubMed

    Oh, Se Heang; Kim, Jin Rae; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Lee, Jin Ho

    2013-03-01

    Polycaprolactone (PCL)/Pluronic F127 nerve guide conduits (NGCs) with different surface pore structures (nano-porous inner surface vs. micro-porous inner surface) but similar physical and chemical properties were fabricated by rolling the opposite side of asymmetrically porous PCL/F127 membranes. The effect of the pore structure on peripheral nerve regeneration through the NGCs was investigated using a sciatic nerve defect model of rats. The nerve fibers and tissues were shown to have regenerated along the longitudinal direction through the NGC with a nano-porous inner surface (Nanopore NGC), while they grew toward the porous wall of the NGC with a micro-porous inner surface (Micropore NGC) and, thus, their growth was restricted when compared with the Nanopore NGC, as investigated by immunohistochemical evaluations (by fluorescence microscopy with anti-neurofilament staining and Hoechst staining for growth pattern of nerve fibers), histological evaluations (by light microscopy with Meyer's modified trichrome staining and Toluidine blue staining and transmission electron microscopy for the regeneration of axon and myelin sheath), and FluoroGold retrograde tracing (for reconnection between proximal and distal stumps). The effect of nerve growth factor (NGF) immobilized on the pore surfaces of the NGCs on nerve regeneration was not so significant when compared with NGCs not containing immobilized NGF. The NGC system with different surface pore structures but the same chemical/physical properties seems to be a good tool that is used for elucidating the surface pore effect of NGCs on nerve regeneration.

  2. A Biosynthetic Nerve Guide Conduit Based on Silk/SWNT/Fibronectin Nanocomposite for Peripheral Nerve Regeneration

    PubMed Central

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Zaminy, Arash; Kokabi, Mehrdad; Soleimani, Masoud; Mirahmadi, Fereshteh

    2013-01-01

    As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts. PMID:24098649

  3. A biosynthetic nerve guide conduit based on silk/SWNT/fibronectin nanocomposite for peripheral nerve regeneration.

    PubMed

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Zaminy, Arash; Kokabi, Mehrdad; Soleimani, Masoud; Mirahmadi, Fereshteh; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2013-01-01

    As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.

  4. Multidimensional conducting polymer nanotubes for ultrasensitive chemical nerve agent sensing.

    PubMed

    Kwon, Oh Seok; Park, Seon Joo; Lee, Jun Seop; Park, Eunyu; Kim, Taejoon; Park, Hyun-Woo; You, Sun Ah; Yoon, Hyeonseok; Jang, Jyongsik

    2012-06-13

    Tailoring the morphology of materials in the nanometer regime is vital to realizing enhanced device performance. Here, we demonstrate flexible nerve agent sensors, based on hydroxylated poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes (HPNTs) with surface substructures such as nanonodules (NNs) and nanorods (NRs). The surface substructures can be grown on a nanofiber surface by controlling critical synthetic conditions during vapor deposition polymerization (VDP) on the polymer nanotemplate, leading to the formation of multidimensional conducting polymer nanostructures. Hydroxyl groups are found to interact with the nerve agents. Representatively, the sensing response of dimethyl methylphosphonate (DMMP) as a simulant for sarin is highly sensitive and reversible from the aligned nanotubes. The minimum detection limit is as low as 10 ppt. Additionally, the sensor had excellent mechanical bendability and durability.

  5. Ultrasound guided nerve block for breast surgery.

    PubMed

    Diéguez, P; Casas, P; López, S; Fajardo, M

    2016-03-01

    The breast surgery has undergone changes in recent years, encouraging new initiatives for the anaesthetic management of these patients in order to achieve maximum quality and rapid recovery. The fundamental tool that has allowed a significant improvement in the progress of regional anaesthesia for breast disease has been ultrasound, boosting the description and introduction into clinical practice of interfascial chest wall blocks, although the reference standard is still the paravertebral block. It is very likely that these blocks will change the protocols in the coming years. A review is presented of the anatomy of the breast region, description of nerve blocks and techniques, as well as their indications, all according to published articles and the opinion of the authors based on their experience.

  6. Mechanical properties of a bioabsorbable nerve guide tube for long nerve defects.

    PubMed

    Ichihara, S; Facca, S; Liverneaux, P; Inada, Y; Takigawa, T; Kaneko, K; Nakamura, T

    2015-09-01

    The mechanical properties of nerve guide tubes must be taken into consideration when they are being developed. We previously reported the feasibility of using 50:50 tubes in a canine 40mm peroneal nerve defect model, where 50:50 represents the proportion of poly(L-lactic) acid (PLLA) and polyglycolic acid (PGA). The aim of the current study was to show that 50:50 tubes have suitable mechanical properties for repairing long nerve defects. Four types of nerve guide tubes made with PLLA to PGA fiber ratios of 100:0 (i.e. 100% PLLA) (100:0 tube), 50:50 (50:50 tube), 10:90 (10:90 tube), and 0:100 (0:100 tube) were designed and created using a tubular braiding machine. Their mechanical properties were examined in vitro (up to 16 weeks). In compression testing, 50:50 tubes had the highest normalized force value, followed in order by the 100:0, 10:90, and 0:100 tubes up to 8 weeks after immersion. From the point of view of biomechanics and bioresorbability, out of the 4 tube types tested, 50:50 tubes appeared to have the optimal mechanical properties for longer nerve defects.

  7. Morphology of nerve fiber regeneration along a biodegradable poly (DLLA-epsilon-CL) nerve guide filled with fresh skeletal muscle.

    PubMed

    Varejão, Artur S P; Cabrita, António M; Meek, Marcel F; Fornaro, Michele; Geuna, Stefano; Giacobini-Robecchi, Maria G

    2003-01-01

    Previous morphological and morphometrical studies showed that fresh-skeletal-muscle-enriched vein segments are good conduits for leading peripheral nerve regeneration. In the present study, we investigated the morphological features of peripheral nerve fibers regenerated along a 10-mm-long biodegradable poly (DLLA-epsilon-CL) nerve guide enriched with fresh skeletal muscle, comparing them to nerve fiber regeneration along 10-mm-long phosphate-buffered saline (PBS)-enriched poly (DLLA-epsilon-CL) tubes. Repaired nerves were analyzed at weeks 6 and 24 postoperatively. Structural and ultrastructural observation showed that good nerve fiber regeneration occurred in both PBS-enriched and fresh-skeletal-muscle-enriched nerve guides, and histomorphometrical analysis of regenerated myelinated fibers revealed no statistically significant differences between the two experimental groups at week 24 after surgery. The employment of fresh-muscle-enriched conduits for the repair of nerve defects is critically discussed in the light of these results.

  8. Pre-differentiation of mesenchymal stromal cells in combination with a microstructured nerve guide supports peripheral nerve regeneration in the rat sciatic nerve model.

    PubMed

    Boecker, Arne Hendrik; van Neerven, Sabien Geraldine Antonia; Scheffel, Juliane; Tank, Julian; Altinova, Haktan; Seidensticker, Katrin; Deumens, Ronald; Tolba, Rene; Weis, Joachim; Brook, Gary Anthony; Pallua, Norbert; Bozkurt, Ahmet

    2016-02-01

    Many bioartificial nerve guides have been investigated pre-clinically for their nerve regeneration-supporting function, often in comparison to autologous nerve transplantation, which is still regarded as the current clinical gold standard. Enrichment of these scaffolds with cells intended to support axonal regeneration has been explored as a strategy to boost axonal regeneration across these nerve guides Ansselin et al. (1998). In the present study, 20 mm rat sciatic nerve defects were implanted with a cell-seeded microstructured collagen nerve guide (Perimaix) or an autologous nerve graft. Under the influence of seeded, pre-differentiated mesenchymal stromal cells, axons regenerated well into the Perimaix nerve guide. Myelination-related parameters, like myelin sheath thickness, benefitted from an additional seeding with pre-differentiated mesenchymal stromal cells. Furthermore, both the number of retrogradely labelled sensory neurons and the axon density within the implant were elevated in the cell-seeded scaffold group with pre-differentiated mesenchymal stromal cells. However, a pre-differentiation had no influence on functional recovery. An additional cell seeding of the Perimaix nerve guide with mesenchymal stromal cells led to an extent of functional recovery, independent of the differentiation status, similar to autologous nerve transplantation. These findings encourage further investigations on pre-differentiated mesenchymal stromal cells as a cellular support for peripheral nerve regeneration.

  9. Ultrasound and electrical nerve stimulation-guided S1 nerve root block.

    PubMed

    Sato, Masaki; Mikawa, Yasuhito; Matuda, Akiko

    2013-10-01

    A selective lumbosacral nerve root block is generally is performed under X-ray fluoroscopy, which has the disadvantage of radiation exposure and the need for fluoroscopy equipment. In this study, we assessed the effectiveness of ultrasound and nerve stimulation-guided S1 nerve root block on 37 patients with S1 radicular syndrome. With the patient in a prone position, an ultrasound scan was performed by placing the probe parallel to the body axis. The needle was pointed slightly medial from the lateral side of the probe and advanced toward a hyperechoic area in the sacral foramina with ultrasound guidance. Contrast medium was then injected and its dispersion confirmed by fluoroscopy. The acquired contrast images were classified into intraneural, perineural, and paraneural patterns. The significance of differences in the effect of the block among the contrast image patterns was analyzed. After nerve block, decreased sensation at the S1 innervated region and pain relief was achieved in all patients. No significant difference was noted in the effect of the block between perineural and paraneural patterns. In conclusion, this technique provided reliable S1 nerve root block in patients with S1 radicular syndrome and minimized radiation exposure.

  10. Sonographic tracking of trunk nerves: essential for ultrasound-guided pain management and research

    PubMed Central

    Chang, Ke-Vin; Lin, Chih-Peng; Lin, Chia-Shiang; Wu, Wei-Ting; Karmakar, Manoj K; Özçakar, Levent

    2017-01-01

    Delineation of architecture of peripheral nerves can be successfully achieved by high-resolution ultrasound (US), which is essential for US-guided pain management. There are numerous musculoskeletal pain syndromes involving the trunk nerves necessitating US for evaluation and guided interventions. The most common peripheral nerve disorders at the trunk region include thoracic outlet syndrome (brachial plexus), scapular winging (long thoracic nerve), interscapular pain (dorsal scapular nerve), and lumbar facet joint syndrome (medial branches of spinal nerves). Until now, there is no single article systematically summarizing the anatomy, sonographic pictures, and video demonstration of scanning techniques regarding trunk nerves. In this review, the authors have incorporated serial figures of transducer placement, US images, and videos for scanning the nerves in the trunk region and hope this paper helps physicians familiarize themselves with nerve sonoanatomy and further apply this technique for US-guided pain medicine and research. PMID:28115867

  11. In vivo integration of poly(ε-caprolactone)/gelatin nanofibrous nerve guide seeded with teeth derived stem cells for peripheral nerve regeneration.

    PubMed

    Beigi, Mohammad-Hossein; Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Karbalaie, Khadijeh; Azadeh, Hamid; Ramakrishna, Seeram; Baharvand, Hossein; Nasr-Esfahani, Mohammad-Hossein

    2014-12-01

    Artificial nanofiber nerve guides have gained huge interest in bridging nerve gaps and associated peripheral nerve regeneration due to its high surface area, flexibility and porous structure. In this study, electrospun poly (ε-caprolactone)/gelatin (PCL/Gel) nanofibrous mats were fabricated, rolled around a copper wire and fixed by medical grade adhesive to obtain a tubular shaped bio-graft, to bridge 10 mm sciatic nerve gap in in vivo rat models. Stem cells from human exfoliated deciduous tooth (SHED) were transplanted to the site of nerve injury through the nanofibrous nerve guides. In vivo experiments were performed in animal models after creating a sciatic nerve gap, such that the nerve gap was grafted using (i) nanofiber nerve guide (ii) nanofiber nerve guide seeded with SHED (iii) suturing, while an untreated nerve gap remained as the negative control. In vitro cell culture study was carried out for primary investigation of SHED-nanofiber interaction and its viability within the nerve guides after 2 and 16 weeks of implantation time. Walking track analysis, plantar test, electrophysiology and immunohistochemistry were performed to evaluate functional recovery during nerve regeneration. Vascularization was also investigated by hematoxilin/eosine (H&E) staining. Overall results showed that the SHED seeded on nanofibrous nerve guide could survive and promote axonal regeneration in rat sciatic nerves, whereby the biocompatible PCL/Gel nerve guide with cells can support axonal regeneration and could be a promising tissue engineered graft for peripheral nerve regeneration.

  12. A guide to the evaluation of fourth cranial nerve palsies.

    PubMed

    Lee; Hayman; Beaver; Prager; Kelder; Scasta; Avilla; von Noorden GK; Tang

    1998-12-01

    PURPOSE To devise a cost-effective guide for the evaluation of fourth nerve palsies (FNP). METHODS A review of the pertinent English language literature was performed to devise a guide for the evaluation (including neuroimaging) of FNP. The authors report a retrospective review of imaging studies performed on 206 patients with FNP. RESULTS The literature was used to develop the imaging guide. In the retrospective chart review of 206 patients from two tertiary care centers, 28 patients (13.6%) underwent a computed tomography scan and/or a magnetic resonance scan. Of these patients, five had associated neurological symptoms (non-isolated), one was traumatic, five were congenital, four were vasculopathic, eleven were non-vasculopathic, and two were progressive. Following the recommendations of the imaging guide, the five isolated congenital FNP and the four isolated vasculopathic FNP would not have undergone neuroimaging studies. The total costs of these neuroimaging studies in these nine patients were 19,000 dollars. Four patients in the retrospective review with associated neurological deficits (non-isolated) should have undergone neuroimaging according to the guide, but did not. CONCLUSIONS Although the evaluation of FNP can be difficult, the decision to order neuroimaging can be improved by using an imaging guide. An imaging guide for the evaluation of FNP may allow more appropriate and cost-effective imaging of these patients. Isolated congenital, old traumatic, or vasculopathic FNP do not require neuroimaging studies. Patients with non-isolated FNP should have directed neuroimaging studies based upon the results of clinical examination.

  13. Peripheral nerve regeneration within an asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    PubMed

    Oh, Se Heang; Kim, Jun Ho; Song, Kyu Sang; Jeon, Byeong Hwa; Yoon, Jin Hwan; Seo, Tae Beom; Namgung, Uk; Lee, Il Woo; Lee, Jin Ho

    2008-04-01

    Asymmetrically porous tubes with selective permeability and hydrophilicity as nerve guide conduits (NGCs) were fabricated using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. The inner surface of the tube had nano-size pores ( approximately 50nm) which can effectively prevent from fibrous tissue infiltration but permeate nutrients and retain neurotrophic factors, while the outer surface had micro-size pores ( approximately 50microm) which can allow vascular ingrowth for effective supply of nutrients into the tube. From the animal study using a rat model, the hydrophilized PLGA/F127 (3wt%) tube showed better nerve regeneration behavior than the control silicone or hydrophobic PLGA tubes, as investigated by immunohistochemical observation (by fluorescent microscopy with anti-neurofilament staining), histological observations (by light microscopy with toluidine blue staining and transmission electron microscopy), and electrophysiological evaluation (by compound muscle action potential measurement). This is probably owing to the effective permeation of nutrients and prevention of fibrous scar tissue invasion as well as the good mechanical strength of the tube to maintain a stable support structure for the nerve regeneration.

  14. Fabrication and characterization of biomimetic multichanneled crosslinked-urethane doped polyester (CUPE) tissue engineered nerve guides

    PubMed Central

    Tran, Richard. T.; Choy, Wai Man; Cao, Hung; Qattan, Ibrahim; Chiao, Jung-Chih; Ip, Wing Yuk; Yeung, Kelvin Wai Kwok; Yang, Jian

    2013-01-01

    Biomimetic scaffolds that replicate the native architecture and mechanical properties of target tissues have been recently shown to be a very promising strategy to guide cellular growth and facilitate tissue regeneration. In this study, porous, soft, and elastic crosslinked urethane-doped polyester (CUPE) tissue engineered nerve guides were fabricated with multiple longitudinally oriented channels and an external non-porous sheath to mimic the native endoneurial microtubular and epineurium structure, respectively. The fabrication technique described herein is highly adaptable and allows for fine control over the resulting nerve guide architecture in terms of channel number, channel diameter, porosity, and mechanical properties. Biomimetic multichanneled CUPE guides were fabricated with various channel numbers and displayed an ultimate peak stress of 1.38 ± 0.22 MPa with a corresponding elongation at break of 122.76 ± 42.17 %, which were comparable to that of native nerve tissue. The CUPE nerve guides were also evaluated in vivo for the repair of a 1 cm rat sciatic nerve defect. Although histological evaluations revealed collapse of the inner structure from CUPE TENGs, the CUPE nerve guides displayed fiber populations and densities comparable with nerve autograft controls after 8 weeks of implantation. These studies are the first report of a CUPE-based biomimetic multichanneled nerve guide and warrant future studies towards optimization of the channel geometry for use in neural tissue engineering. PMID:24115502

  15. Fabrication and characterization of biomimetic multichanneled crosslinked-urethane-doped polyester tissue engineered nerve guides.

    PubMed

    Tran, Richard T; Choy, Wai Man; Cao, Hung; Qattan, Ibrahim; Chiao, Jung-Chih; Ip, Wing Yuk; Yeung, Kelvin Wai Kwok; Yang, Jian

    2014-08-01

    Biomimetic scaffolds that replicate the native architecture and mechanical properties of target tissues have been recently shown to be a very promising strategy to guide cellular growth and facilitate tissue regeneration. In this study, porous, soft, and elastic crosslinked urethane-doped polyester (CUPE) tissue engineered nerve guides were fabricated with multiple longitudinally oriented channels and an external non-porous sheath to mimic the native endoneurial microtubular and epineurium structure, respectively. The fabrication technique described herein is highly adaptable and allows for fine control over the resulting nerve guide architecture in terms of channel number, channel diameter, porosity, and mechanical properties. Biomimetic multichanneled CUPE guides were fabricated with various channel numbers and displayed an ultimate peak stress of 1.38 ± 0.22 MPa with a corresponding elongation at break of 122.76 ± 42.17%, which were comparable to that of native nerve tissue. The CUPE nerve guides were also evaluated in vivo for the repair of a 1 cm rat sciatic nerve defect. Although histological evaluations revealed collapse of the inner structure from CUPE TENGs, the CUPE nerve guides displayed fiber populations and densities comparable with nerve autograft controls after 8 weeks of implantation. These studies are the first report of a CUPE-based biomimetic multichanneled nerve guide and warrant future studies towards optimization of the channel geometry for use in neural tissue engineering.

  16. Chitosan-cross-linked nanofibrous PHBV nerve guide for rat sciatic nerve regeneration across a defect bridge.

    PubMed

    Biazar, Esmaeil; Keshel, Saeed Heidari

    2013-01-01

    The aim of this study was to produce a chitosan-cross-linked nanofibrous biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit. The artificial nerve scaffold designed by electrospinning method and cross-linked with chitosan by chemical method. Afterwards, the scaffolds were evaluated by microscopic, physical, and mechanical analyses and cell culture assays with Schwann cells. The conduits were implanted into a 10 mm gap in the sciatic nerves of the rats. Four months after surgery, the regenerated nerves were evaluated by macroscopic assessments and histology. This polymeric conduit had sufficiently good mechanical properties to serve as a nerve guide. Cellular experiments showed a better cell adhesion, growth, and proliferation inside the cross-linked nanofibrous scaffolds compared with un-cross-linked ones, also Schwann cells well attached on chitosan-cross-linked nanofibrous surface. The in vivo results demonstrated that in the nanofibrous graft, the sciatic nerve trunk had been reconstructed with restoration of nerve continuity and formatted nerve fibers with myelination. This neural conduit appears to have the right organization for testing in vivo nerve tissue engineering studies.

  17. Risk of Encountering Dorsal Scapular and Long Thoracic Nerves during Ultrasound-guided Interscalene Brachial Plexus Block with Nerve Stimulator

    PubMed Central

    Kim, Yeon Dong; Yu, Jae Yong; Shim, Junho; Heo, Hyun Joo

    2016-01-01

    Background Recently, ultrasound has been commonly used. Ultrasound-guided interscalene brachial plexus block (IBPB) by posterior approach is more commonly used because anterior approach has been reported to have the risk of phrenic nerve injury. However, posterior approach also has the risk of causing nerve injury because there are risks of encountering dorsal scapular nerve (DSN) and long thoracic nerve (LTN). Therefore, the aim of this study was to evaluate the risk of encountering DSN and LTN during ultrasound-guided IBPB by posterior approach. Methods A total of 70 patients who were scheduled for shoulder surgery were enrolled in this study. After deciding insertion site with ultrasound, awake ultrasound-guided IBPB with nerve stimulator by posterior approach was performed. Incidence of muscle twitches (rhomboids, levator scapulae, and serratus anterior muscles) and current intensity immediately before muscle twitches disappeared were recorded. Results Of the total 70 cases, DSN was encountered in 44 cases (62.8%) and LTN was encountered in 15 cases (21.4%). Both nerves were encountered in 10 cases (14.3%). Neither was encountered in 21 cases (30.4%). The average current measured immediately before the disappearance of muscle twitches was 0.44 mA and 0.50 mA at DSN and LTN, respectively. Conclusions Physicians should be cautious on the risk of injury related to the anatomical structures of nerves, including DSN and LTN, during ultrasound-guided IBPB by posterior approach. Nerve stimulator could be another option for a safer intervention. Moreover, if there is a motor response, it is recommended to select another way to secure better safety. PMID:27413483

  18. The role of microstructured and interconnected pore channels in a collagen-based nerve guide on axonal regeneration in peripheral nerves.

    PubMed

    Bozkurt, Ahmet; Lassner, Franz; O'Dey, Dan; Deumens, Ronald; Böcker, Arne; Schwendt, Tilman; Janzen, Christoph; Suschek, Christoph V; Tolba, Rene; Kobayashi, Eiji; Sellhaus, Bernd; Tholl, S; Eummelen, Lizette; Schügner, Frank; Damink, Leon Olde; Weis, Joachim; Brook, Gary A; Pallua, Norbert

    2012-02-01

    The use of bioengineered nerve guides as alternatives for autologous nerve transplantation (ANT) is a promising strategy for the repair of peripheral nerve defects. In the present investigation, we present a collagen-based micro-structured nerve guide (Perimaix) for the repair of 2 cm rat sciatic nerve defects. Perimaix is an open-porous biodegradable nerve guide containing continuous, longitudinally orientated channels for orientated nerve growth. The effects of these nerve guides on axon regeneration by six weeks after implantation have been compared with those of ANT. Investigation of the regenerated sciatic nerve indicated that Perimaix strongly supported directed axon regeneration. When seeded with cultivated rat Schwann cells (SC), the Perimaix nerve guide was found to be almost as supportive of axon regeneration as ANT. The use of SC from transgenic green-fluorescent-protein (GFP) rats allowed us to detect the viability of donor SC at 1 week and 6 weeks after transplantation. The GFP-positive SC were aligned in a columnar fashion within the longitudinally orientated micro-channels. This cellular arrangement was not only observed prior to implantation, but also at one week and 6 weeks after implantation. It may be concluded that Perimaix nerve guides hold great promise for the repair of peripheral nerve defects.

  19. AMEM-ADL Polymer Migration Estimation Model User's Guide

    EPA Pesticide Factsheets

    The user's guide of the Arthur D. Little Polymer Migration Estimation Model (AMEM) provides the information on how the model estimates the fraction of a chemical additive that diffuses through polymeric matrices.

  20. Acceleration of peripheral nerve regeneration through asymmetrically porous nerve guide conduit applied with biological/physical stimulation.

    PubMed

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2013-12-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve.

  1. Ultrastructural analysis of guided nerve regeneration using progesterone- and pregnenolone-loaded chitosan prostheses.

    PubMed

    Chávez-Delgado, M E; Gomez-Pinedo, U; Feria-Velasco, A; Huerta-Viera, M; Castañeda, S Castro; Toral, F A López-Dellamary; Parducz, A; Anda, S Luquín-De; Mora-Galindo, J; García-Estrada, J

    2005-07-01

    Recently, numerous guide chambers for the treatment of injured nerves made up of different biomaterials have been designed, capable of hosting living cells or carrying neurotrophic or neuroactive substances to be directly released to the injured tissue. In this study, chitosan prostheses containing neurosteroids (progesterone and pregnenolone) were used for bridging a 10-mm gap in the rabbit facial nerve. Gas chromatography was used to quantify neurosteroid content in the prostheses prior to and after subcutaneous implantation at different periods of up to 60 days. The regeneration of the nerve fibers were evaluated at 15 and 45 days after axotomy by means of ultrastructural morphometric analysis. Different nerve fibers regenerative patterns were seen depending the groups studied and the analyzed stages. At 15 days after axotomy, the newly regenerating tissue revealed Schwann cells holding nonmyelinated nerve fiber bundles in an incipient and organized regenerative pattern. At 45 days, the regenerating tissue showed myelinated nerve fibers of different sizes, shapes, and myelin sheath thickness. Although the regeneration of the nerve fibers under neurosteroid treatment showed statistically significant differences in comparison with vehicle regenerated tissue, progesterone-loaded chitosan prostheses produced the best guided nerve regeneration response. These findings indicate that chitosan prostheses allowed regeneration of nerve fibers in their lumen, and when containing neurosteroids produced a faster guided nerve regeneration acting as a long-lasting release delivery vehicle.

  2. Treatment of great auricular neuralgia with real-time ultrasound-guided great auricular nerve block

    PubMed Central

    Jeon, Younghoon; Kim, Saeyoung

    2017-01-01

    Abstract Rationale: The great auricular nerve can be damaged by the neck surgery, tumor, and long-time pressure on the neck. But, great auricular neuralgia is very rare condition. It was managed by several medication and landmark-based great auricular nerve block with poor prognosis. Patient concerns: A 25-year-old man presented with a pain in the left lateral neck and auricle. Diagnosis: He was diagnosed with great auricular neuralgia. Interventions: His pain was not reduced by medication. Therefore, the great auricular nerve block with local anesthetics and steroid was performed under ultrasound guidance. Outcomes: Ultrasound guided great auricular nerve block alleviated great auricular neuralgia. Lessons: This medication-resistant great auricular neuralgia was treated by the ultrasound guided great auricular nerve block with local anesthetic agent and steroid. Therefore, great auricular nerve block can be a good treatment option of medication resistant great auricular neuralgia. PMID:28328811

  3. Magnetic resonance neurography-guided nerve blocks for the diagnosis and treatment of chronic pelvic pain syndrome.

    PubMed

    Fritz, Jan; Chhabra, Avneesh; Wang, Kenneth C; Carrino, John A

    2014-02-01

    Magnetic resonance (MR) neurography - guided nerve blocks and injections describe a techniques for selective percutaneous drug delivery, in which limited MR neurography and interventional MR imaging are used jointly to map and target specific pelvic nerves or muscles, navigate needles to the target, visualize the injected drug and detect spread to confounding structures. The procedures described, specifically include nerve blocks of the obturator nerve, lateral femoral cutaneous nerve, pudendal nerve, posterior femoral cutaneous nerve, sciatic nerve, ganglion impar, sacral spinal nerve, and injection into the piriformis muscle.

  4. Ultrasound-stimulated peripheral nerve regeneration within asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    PubMed

    Park, Sang Chul; Oh, Se Heang; Seo, Tae Beom; Namgung, Uk; Kim, Jin Man; Lee, Jin Ho

    2010-08-01

    Recently, we developed a novel method to fabricate a nerve guide conduit (NGC) with asymmetrical pore structure and hydrophilicity using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. From the animal study using a rat model (sciatic nerve defect of rat), we recognized that the unique PLGA/Pluronic F127 tube provided good environments for nerve regeneration. In this study, we applied low-intensity pulsed ultrasound as a simple and noninvasive stimulus at the PLGA/F127 NGC-implanted site transcutaneously in rats to investigate the feasibility of ultrasound for the enhanced nerve regeneration through the tube. The nerve regeneration behaviors within the ultrasound-stimulated PLGA/Pluronic F127 NGCs were compared with the NGCs without the ultrasound treatment as well as normal nerve by histological and immunohistochemical observations. It was observed that the PLGA/Pluronic F127 tube-implanted group applied with the ultrasound had more rapid nerve regeneration behavior (approximately 0.71 mm/day) than the tube-implanted group without the ultrasound treatment (approximately 0.48 mm/day). The ultrasound-treated tube group also showed greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the ultrasound treatment, indicating better nerve regeneration. The better nerve regeneration behavior in the our NGC/ultrasound system may be caused by the synergistic effect of the asymmetrically porous PLGA/Pluronic F127 tube with unique properties (selective permeability, hydrophilicity, and structural stability, which can provide good environment for nerve regeneration) and physical stimulus (stimulation of the Schwann cells and activation of the neurotrophic factors).

  5. Electrospun poly(L-lactide-co-glycolide) biodegradable polymer nanofibre tubes for peripheral nerve regeneration

    NASA Astrophysics Data System (ADS)

    Bini, T. B.; Gao, Shujun; Chyan Tan, Ter; Wang, Shu; Lim, Aymeric; Ben Hai, Lim; Ramakrishna, S.

    2004-11-01

    Nanotechnology is an area receiving increasing attention as progress is made towards tailoring the morphology of polymeric biomaterial for a variety of applications. In the present study an attempt was made to electrospin poly(L-lactide-co-glycolide) biodegradable polymer nanofibres. In this process, polymer fibres with diameters down to the nanometre range are formed by subjecting a fluid jet to a high electric field. The nanofibres were collected on to a rotating Teflon mandrel and fabricated to tubes or conduits, to function as nerve guidance channels. The feasibility of in vivo nerve regeneration was investigated through several of these conduits. The biological performance of the conduits were examined in the rat sciatic nerve model with a 10 mm gap length. After implantation of the nanofibre nerve guidance conduit to the right sciatic nerve of the rat, there was no inflammatory response. One month after implantation five out of eleven rats showed successful nerve regeneration. None of the implanted tubes showed tube breakage. The nanofibre nerve guidance conduits were flexible, permeable and showed no swelling. Thus, these new poly(L-lactide-co-glycolide) nanofibre conduits can be effective aids for nerve regeneration and repair. Improvements could be done by impregnating nerve growth factors or Schwann cells and may lead to clinical applications.

  6. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect.

    PubMed

    Luo, Lihua; Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan; Wang, Xiong; Huselstein, Celine; Chen, Yun

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  7. A Novel CT-Guided Transpsoas Approach to Diagnostic Genitofemoral Nerve Block and Ablation

    PubMed Central

    Parris, David; Fischbein, Nancy; Mackey, Sean; Carroll, Ian

    2010-01-01

    Background Inguinal hernia repair is associated with a high incidence of chronic postsurgical pain. This pain may be caused by injury to the iliohypogastric, ilioinguinal, or genitofemoral nerves. It is often difficult to identify the specific source of the pain, in part, because these nerves are derived from overlapping nerve roots and closely colocalize in the area of surgery. It is therefore technically difficult to selectively block these nerves individually proximal to the site of surgical injury. In particular, the genitofemoral nerve is retroperitoneal before entering the inguinal canal, a position that puts anterior approaches to the proximal nerve at risk of transgressing into the peritoneum. We report a computed tomography (CT)-guided transpsoas technique to selectively block the genitofemoral nerve for both diagnostic and therapeutic purposes while avoiding injury to the nearby ureter and intestines. Case A 39-year-old woman with chronic lancinating right groin pain after inguinal hernia repair underwent multiple pharmacologic interventions and invasive procedures without relief. Using CT and Stimuplex nerve stimulator guidance, the genitofemoral nerve was localized on the anterior surface of the psoas muscle and a diagnostic block with local anesthetic block was performed. The patient had immediate relief of her symptoms for 36 hours, confirming the diagnosis of genitofemoral neuralgia. She subsequently underwent CT-guided radiofrequency and phenol ablation of the genitofemoral nerve but has not achieved long-term analgesia. Conclusion CT-guided transpsoas genitofemoral nerve block is a viable option for safely and selectively blocking the genitofemoral nerve for diagnostic or therapeutic purposes proximal to injury caused by inguinal surgery. PMID:20546515

  8. Ultrasound-Guided Genicular Nerve Thermal Radiofrequency Ablation for Chronic Knee Pain

    PubMed Central

    Wong, Joshua; Weyker, Paul D.

    2016-01-01

    Osteoarthritis (OA) of the knee is one of the most common joint diseases affecting adults in the United States. For elderly patients with multiple medical comorbidities who do not wish to undergo total knee arthroplasty (TKA), lifestyle modification, pharmacologic management, and injections are the mainstay of therapy. Previously, pain management interventions were limited to intra-articular joint injections and viscosupplementation with hyaluronic acid. Fluoroscopic-guided techniques for radiofrequency ablation (RFA) of the genicular nerves have been previously described and a recent cadaveric study suggests that ultrasound-guided genicular nerve blocks can be performed accurately. We performed an ultrasound-guided radiofrequency ablation of the genicular nerves in 88-year-old woman who had deferred surgical management given her age. Following successful ultrasound guided diagnostic genicular nerve blocks, she proceeded to RFA using the same ultrasound guided technique. The procedure resulted in significant pain relief and improvement in overall function for greater than 6 months. The use of ultrasound provides a relatively rapid and noninvasive method to directly visualize genicular nerves and surrounding vasculature. Our case suggests that, for genicular nerve blockade and RFA, ultrasound may be a useful alternative to fluoroscopy. Not only did the procedure result in significant pain relief that has persisted for greater than 6 months but also more importantly her function status and quality of life were improved. PMID:27822391

  9. Application of Hydrogen Bond Acidic Polycarbosilane Polymers and Solid-Phase Microextraction for the Collection of Nerve Agent Simulant

    DTIC Science & Technology

    2006-01-01

    and analyzed on a GC/MS with a SPME injection port. 20 3. Methodolgy This chapter describes the methods used to answer the research questions...can be improved by using a SPME polymer coating that is selective for nerve agents in place of current commercial polymers. This research focuses on...three hydrogen bond acidic polymers developed by the Naval Research Laboratory that have an increased affinity for nerve agents. These polymers

  10. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect

    SciTech Connect

    Luo, Lihua; Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan; Wang, Xiong; Huselstein, Celine; Chen, Yun

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  11. Electrically conductive biodegradable polymer composite for nerve regeneration: electricity-stimulated neurite outgrowth and axon regeneration.

    PubMed

    Zhang, Ze; Rouabhia, Mahmoud; Wang, Zhaoxu; Roberge, Christophe; Shi, Guixin; Roche, Phillippe; Li, Jiangming; Dao, Lê H

    2007-01-01

    Normal and electrically stimulated PC12 cell cultures and the implantation of nerve guidance channels were performed to evaluate newly developed electrically conductive biodegradable polymer composites. Polypyrrole (PPy) doped by butane sulfonic acid showed a significantly higher number of viable cells compared with PPy doped by polystyrenesulfonate after a 6-day culture. The PC12 cells were left to proliferate for 6 days, and the PPy-coated membranes, showing less initial cell adherence, recorded the same proliferation rate as did the noncoated membranes. Direct current electricity at various intensities was applied to the PC12 cell-cultured conductive membranes. After 7 days, the greatest number of neurites appeared on the membranes with a current intensity approximating 1.7-8.4 microA/cm. Nerve guidance channels made of conductive biodegradable composite were implanted into rats to replace 8 mm of sciatic nerve. The implants were harvested after 2 months and analyzed with immunohistochemistry and transmission electron microscopy. The regenerated nerve tissue displayed myelinated axons and Schwann cells that were similar to those in the native nerve. Electrical stimulation applied through the electrically conductive biodegradable polymers therefore enhanced neurite outgrowth in a current-dependent fashion. The conductive polymers also supported sciatic nerve regeneration in rats.

  12. Polymer microstructured optical fibers for terahertz wave guiding.

    PubMed

    Ung, Bora; Mazhorova, Anna; Dupuis, Alexandre; Rozé, Mathieu; Skorobogatiy, Maksim

    2011-12-12

    We outline the most recent technological advancements in the design, fabrication and characterization of polymer microstructured optical fibers (MOFs) for applications in the terahertz waveband. Focusing on specific experimental demonstrations, we show that polymer optical fibers provide a very flexible route towards THz wave guiding. Crucial incentives include the large variety of the low-cost and relatively low absorption loss polymers, the facile fiber preform fabrication by molding, drilling, stacking and extrusion, and finally, the simple fabrication through fiber drawing at low forming temperatures.

  13. Biological performance of a novel biodegradable polyamidoamine hydrogel as guide for peripheral nerve regeneration.

    PubMed

    Magnaghi, Valerio; Conte, Vincenzo; Procacci, Patrizia; Pivato, Giorgio; Cortese, Paolo; Cavalli, Erika; Pajardi, Giorgio; Ranucci, Elisabetta; Fenili, Fabio; Manfredi, Amedea; Ferruti, Paolo

    2011-07-01

    Polyamidoamines (PAAs) are a well-known family of synthetic biocompatible and biodegradable polymers, which can be prepared as soft hydrogels characterized by low interfacial tension and tunable elasticity. For the first time we report here on the in vivo performance of a PAA hydrogel implant as scaffold for tissue engineering. In particular, an amphoteric agmatine-deriving PAA hydrogel shaped as small tubing was obtained by radical polymerization of a soluble functional oligomeric precursor and used as conduit for nerve regeneration in a rat sciatic nerve cut model. The animals were analyzed at 30, 90, and 180 days post-surgery. PAA tubing proved to facilitate nerve regeneration. Good surgical outcomes were achieved with no signs of inflammation or neuroma. Moreover, nerve regeneration was morphologically sound and the quality of functional recovery satisfactory. In conclusion, PAA hydrogel scaffolds may represent a novel and promising material for peripheral nerve regeneration.

  14. Application of conductive polymers, scaffolds and electrical stimulation for nerve tissue engineering.

    PubMed

    Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein; Kiani, Sahar; Al-Deyab, Salem S; Ramakrishna, Seeram

    2011-04-01

    Among the numerous attempts to integrate tissue engineering concepts into strategies to repair nearly all parts of the body, neuronal repair stands out. This is partially due to the complexity of the nervous anatomical system, its functioning and the inefficiency of conventional repair approaches, which are based on single components of either biomaterials or cells alone. Electrical stimulation has been shown to enhance the nerve regeneration process and this consequently makes the use of electrically conductive polymers very attractive for the construction of scaffolds for nerve tissue engineering. In this review, by taking into consideration the electrical properties of nerve cells and the effect of electrical stimulation on nerve cells, we discuss the most commonly utilized conductive polymers, polypyrrole (PPy) and polyaniline (PANI), along with their design and modifications, thus making them suitable scaffolds for nerve tissue engineering. Other electrospun, composite, conductive scaffolds, such as PANI/gelatin and PPy/poly(ε-caprolactone), with or without electrical stimulation, are also discussed. Different procedures of electrical stimulation which have been used in tissue engineering, with examples on their specific applications in tissue engineering, are also discussed.

  15. Ultrasound-Guided Proximal Suprascapular Nerve Block With Radiofrequency Lesioning for Patients With Malignancy-Associated Recalcitrant Shoulder Pain.

    PubMed

    Chang, Ke-Vin; Hung, Chen-Yu; Wang, Tyng-Guey; Yang, Rong-Sen; Sun, Wei-Zen; Lin, Chih-Peng

    2015-11-01

    The classic suprascapular nerve block has limitations, such as postural requirements and lack of direct nerve visualization. This series investigated the analgesic effect of ultrasound-guided supraclavicular suprascapular nerve blocks in patients with malignancy-associated shoulder pain. Ablative radiofrequency lesioning of the suprascapular nerve in 6 patients provided substantial pain relief. The mean distance from the suprascapular nerve to the brachial plexus was 8.05 mm, and the mean angle of needle entry was 20.6°. This approach appears to be effective in relieving malignancy-associated shoulder pain and is tolerated by patients unable to sit or lie prone.

  16. Design and fabrication of a nanofibrous polycaprolactone tubular nerve guide for peripheral nerve tissue engineering using a two-pole electrospinning system.

    PubMed

    Panahi-Joo, Y; Karkhaneh, A; Nourinia, A; Abd-Emami, B; Negahdari, B; Renaud, P; Bonakdar, S

    2016-04-12

    Nerve guidance conduits are considered to be the new generation of scaffolds designed for nerve disorders. A tubular construct with a highly aligned fibrous structure, mimicking the endoneurium layer surrounding inner axons of a nerve fascicle, is a suitable candidate for a nerve guide. In this paper a new approach for the fabrication of 3D tubular nerve guides is introduced using simulation of a two-pole electrospinning system and describing its mechanism. The structure of this scaffold is then optimized using the Taguchi statistical method and after morphological studies by scanning electron microscopy, the crystallinity, tensile strength and protein adsorption of these highly aligned fibres are investigated, comparing them with semi-aligned and random fibres produced via conventional mandrel electrospinning. Cell attachment, proliferation and migration of PC12 neuronal like cells are studied on highly aligned, semi aligned and random structures, and morphological change and elongation are observed in PC12 cells. The results of these studies suggest that conduits fabricated using two-pole electrospinning are a suitable and promising scaffold for peripheral and even spinal nerve regeneration. This nerve guide has a great potential for further advanced modifications and regeneration in higher levels.

  17. Ultrasound-guided Pulsed Radiofrequency Lesioning of the Phrenic Nerve in a Patient with Intractable Hiccup

    PubMed Central

    Kang, Keum Nae; Park, In Kyung; Suh, Jeong Hun; Leem, Jeong Gill

    2010-01-01

    Persistent and intractable hiccups (with respective durations of more than 48 hours and 1 month) can result in depression, fatigue, impaired sleep, dehydration, weight loss, malnutrition, and aspiration syndromes. The conventional treatments for hiccups are either non-pharmacological, pharmacological or a nerve block treatment. Pulsed radiofrequency lesioning (PRFL) has been proposed for the modulation of the excited nervous system pathway of pain as a safe and nondestructive treatment method. As placement of the electrode in close proximity to the targeted nerve is very important for the success of PRFL, ultrasound appears to be well suited for this technique. A 74-year-old man suffering from intractable hiccups that had developed after a coronary artery bypass graft and had continued for 7 years was referred to our pain clinic. He had not been treated with conventional methods or medications. We performed PRFL of the phrenic nerve guided by ultrasound and the hiccups disappeared. PMID:20830266

  18. Macrophage-Induced Blood Vessels Guide Schwann Cell-Mediated Regeneration of Peripheral Nerves.

    PubMed

    Cattin, Anne-Laure; Burden, Jemima J; Van Emmenis, Lucie; Mackenzie, Francesca E; Hoving, Julian J A; Garcia Calavia, Noelia; Guo, Yanping; McLaughlin, Maeve; Rosenberg, Laura H; Quereda, Victor; Jamecna, Denisa; Napoli, Ilaria; Parrinello, Simona; Enver, Tariq; Ruhrberg, Christiana; Lloyd, Alison C

    2015-08-27

    The peripheral nervous system has remarkable regenerative capacities in that it can repair a fully cut nerve. This requires Schwann cells to migrate collectively to guide regrowing axons across a 'bridge' of new tissue, which forms to reconnect a severed nerve. Here we show that blood vessels direct the migrating cords of Schwann cells. This multicellular process is initiated by hypoxia, selectively sensed by macrophages within the bridge, which via VEGF-A secretion induce a polarized vasculature that relieves the hypoxia. Schwann cells then use the blood vessels as "tracks" to cross the bridge taking regrowing axons with them. Importantly, disrupting the organization of the newly formed blood vessels in vivo, either by inhibiting the angiogenic signal or by re-orienting them, compromises Schwann cell directionality resulting in defective nerve repair. This study provides important insights into how the choreography of multiple cell-types is required for the regeneration of an adult tissue.

  19. Analgesic Efficacy and Technique of Ultrasound-Guided Suprascapular Nerve Catheters after Shoulder Arthroscopy

    PubMed Central

    Elsharkawy, Hesham A.; Abd-Elsayed, Alaa A.; Cummings, Kenneth C.; Soliman, Loran Mounir

    2014-01-01

    Background Conventional approaches to brachial plexus blocks may not cover the suprascapular nerve. Accordingly, after shoulder arthroscopy, sensation from the posterior part of the shoulder is commonly spared. Most previous research involving suprascapular nerve blocks described single-injection techniques. However, with the widespread availability and fairly reasonable cost of disposable infusion pumps, continuous catheter techniques provide a more appealing method of prolonging postoperative analgesia. Case Report We describe 2 patients who were successfully treated with ultrasound-guided continuous suprascapular nerve catheters. With the patient seated, a high-frequency linear ultrasound probe was used. Both patients experienced excellent pain relief without complications. Conclusion Continuous suprascapular catheter techniques provide good pain relief and improve postoperative analgesia after shoulder arthroscopy. PMID:24940138

  20. Computationally Guided Design of Polymer Electrolytes for Battery Applications

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-Gang; Webb, Michael; Savoie, Brett; Miller, Thomas

    We develop an efficient computational framework for guiding the design of polymer electrolytes for Li battery applications. Short-times molecular dynamics (MD) simulations are employed to identify key structural and dynamic features in the solvation and motion of Li ions, such as the structure of the solvation shells, the spatial distribution of solvation sites, and the polymer segmental mobility. Comparative studies on six polyester-based polymers and polyethylene oxide (PEO) yield good agreement with experimental data on the ion conductivities, and reveal significant differences in the ion diffusion mechanism between PEO and the polyesters. The molecular insights from the MD simulations are used to build a chemically specific coarse-grained model in the spirit of the dynamic bond percolation model of Druger, Ratner and Nitzan. We apply this coarse-grained model to characterize Li ion diffusion in several existing and yet-to-be synthesized polyethers that differ by oxygen content and backbone stiffness. Good agreement is obtained between the predictions of the coarse-grained model and long-timescale atomistic MD simulations, thus providing validation of the model. Our study predicts higher Li ion diffusivity in poly(trimethylene oxide-alt-ethylene oxide) than in PEO. These results demonstrate the potential of this computational framework for rapid screening of new polymer electrolytes based on ion diffusivity.

  1. Ultrasound-Guided Obturator Nerve Block: A Focused Review on Anatomy and Updated Techniques

    PubMed Central

    Nakamoto, Tatsuo; Kamibayashi, Takahiko

    2017-01-01

    This review outlines the anatomy of the obturator nerve and the indications for obturator nerve block (ONB). Ultrasound-guided ONB techniques and unresolved issues regarding these procedures are also discussed. An ONB is performed to prevent thigh adductor jerk during transurethral resection of bladder tumor, provide analgesia for knee surgery, treat hip pain, and improve persistent hip adductor spasticity. Various ultrasound-guided ONB techniques can be used and can be classified according to whether the approach is distal or proximal. In the distal approach, a transducer is placed at the inguinal crease; the anterior and posterior branches of the nerve are then blocked by two injections of local anesthetic directed toward the interfascial planes where each branch lies. The proximal approach comprises a single injection of local anesthetic into the interfascial plane between the pectineus and obturator externus muscles. Several proximal approaches involving different patient and transducer positions are reported. The proximal approach may be superior for reducing the dose of local anesthetic and providing successful blockade of the obturator nerve, including the hip articular branch, when compared with the distal approach. This hypothesis and any differences between the proximal ONB techniques need to be explored in future studies. PMID:28280738

  2. Interventional multispectral photoacoustic imaging with a clinical linear array ultrasound probe for guiding nerve blocks

    NASA Astrophysics Data System (ADS)

    Xia, Wenfeng; West, Simeon J.; Nikitichev, Daniil I.; Ourselin, Sebastien; Beard, Paul C.; Desjardins, Adrien E.

    2016-03-01

    Accurate identification of tissue structures such as nerves and blood vessels is critically important for interventional procedures such as nerve blocks. Ultrasound imaging is widely used as a guidance modality to visualize anatomical structures in real-time. However, identification of nerves and small blood vessels can be very challenging, and accidental intra-neural or intra-vascular injections can result in significant complications. Multi-spectral photoacoustic imaging can provide high sensitivity and specificity for discriminating hemoglobin- and lipid-rich tissues. However, conventional surface-illumination-based photoacoustic systems suffer from limited sensitivity at large depths. In this study, for the first time, an interventional multispectral photoacoustic imaging (IMPA) system was used to image nerves in a swine model in vivo. Pulsed excitation light with wavelengths in the ranges of 750 - 900 nm and 1150 - 1300 nm was delivered inside the body through an optical fiber positioned within the cannula of an injection needle. Ultrasound waves were received at the tissue surface using a clinical linear array imaging probe. Co-registered B-mode ultrasound images were acquired using the same imaging probe. Nerve identification was performed using a combination of B-mode ultrasound imaging and electrical stimulation. Using a linear model, spectral-unmixing of the photoacoustic data was performed to provide image contrast for oxygenated and de-oxygenated hemoglobin, water and lipids. Good correspondence between a known nerve location and a lipid-rich region in the photoacoustic images was observed. The results indicate that IMPA is a promising modality for guiding nerve blocks and other interventional procedures. Challenges involved with clinical translation are discussed.

  3. Pain management via Ultrasound-guided Nerve Block in Emergency Department; a Case Series Study

    PubMed Central

    Nejati, Amir; Teymourian, Houman; Behrooz, Leili; mohseni, Gholamreza

    2017-01-01

    Introduction: Pain is the most common complaint of patients referring to emergency department (ED). Considering the importance of pain management in ED, this study aimed to investigate the efficacy and feasibility of ultrasound-guided nerve blocks in this setting. Methods: 46 patients who came to the ED with injured extremities were enrolled in the study and received either femoral, axillary or sciatic nerve block depending on their site of injury (1.5 mg Bupivacaine per kg of patient’s weight). Patients were asked about their level of pain before and after receiving the nerve block based on numerical rating scale. The difference between pre and post block pain severity was measured. Both patients and physicians were asked about their satisfaction with the nerve block in 5 tiered Likert scale. Results: 46 patients with the mean age of 37.5 ± 12.5 years (8-82 years) received ultrasound-guided nerve block (84.8% male). 6 Sciatic, 25 axillary, and 15 femoral nerve blocks were performed. Mean pain severity on NRS score at the time of admission was 8.1 ± 1.4, which reduced to 2.04 ± 2.06 after block. 25 (54.3%) patients were highly satisfied (Likert scale 5), 15 (32.6%) were satisfied (Likert scale 4), 3 (6.5%) were neutral and had no opinion (Likert scale 3), 1 (2.1%) was not satisfied (Likert scale 2), and 2 (4.3%) were highly unsatisfied (Likert scale 1). There was no significant difference among the satisfaction scores within the three block locations (p = 0.8). There was no significant difference in physicians’ level of satisfaction between the three block locations either (p = 0.9). 1 (2.1%) case of agitation and tachycardia and 1 (2.1%) case of vomiting were observed after the procedure. Conclusion: Ultrasound-guided nerve block of extremities is a safe and effective method that can be used for pain management in the ED. It results in high levels of satisfaction among both patients and physicians.

  4. Crosslinking of micropatterned collagen-based nerve guides to modulate the expected half-life.

    PubMed

    Salvatore, L; Madaghiele, M; Parisi, C; Gatti, F; Sannino, A

    2014-12-01

    The microstructural, mechanical, compositional, and degradative properties of a nerve conduit are known to strongly affect the regenerative process of the injured peripheral nerve. Starting from the fabrication of micropatterned collagen-based nerve guides, according to a spin-casting process reported in the literature, this study further investigates the possibility to modulate the degradation rate of the scaffolds over a wide time frame, in an attempt to match different rates of nerve regeneration that might be encountered in vivo. To this aim, three different crosslinking methods, that is, dehydrothermal (DHT), carbodiimide-based (EDAC), and glutaraldehyde-based (GTA) crosslinking, were selected. The elastically effective degree of crosslinking, attained by each method and evaluated according to the classical rubber elasticity theory, was found to significantly tune the in vitro half-life (t1/2 ) of the matrices, with an exponential dependence of the latter on the crosslink density. The high crosslinking efficacy of EDAC and GTA treatments, respectively threefold and fourfold when compared to the one attained by DHT, led to a sharp increase of the corresponding in vitro half-lives (ca., 10, 172, and 690 h, for DHT, EDAC, and GTA treated matrices, respectively). As shown by cell viability assays, the cytocompatibility of both DHT and EDAC treatments, as opposed to the toxicity of GTA, suggests that such methods are suitable to crosslink collagen-based scaffolds conceived for clinical use. In particular, nerve guides with expected high residence times in vivo might be produced by finely controlling the biocompatible reaction(s) adopted for crosslinking.

  5. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration.

    PubMed

    Widmer, M S; Gupta, P K; Lu, L; Meszlenyi, R K; Evans, G R; Brandt, K; Savel, T; Gurlek, A; Patrick, C W; Mikos, A G

    1998-11-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  6. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration

    NASA Technical Reports Server (NTRS)

    Widmer, M. S.; Gupta, P. K.; Lu, L.; Meszlenyi, R. K.; Evans, G. R.; Brandt, K.; Savel, T.; Gurlek, A.; Patrick, C. W. Jr; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  7. Carboxylic Acid-Functionalized Conducting-Polymer Nanotubes as Highly Sensitive Nerve-Agent Chemiresistors

    NASA Astrophysics Data System (ADS)

    Kwon, Oh Seok; Park, Chul Soon; Park, Seon Joo; Noh, Seonmyeong; Kim, Saerona; Kong, Hye Jeong; Bae, Joonwon; Lee, Chang-Soo; Yoon, Hyeonseok

    2016-09-01

    Organophosphates are powerful inhibitors of acetylcholinesterase, which is critical to nerve function. Despite continuous research for detecting the highly toxic organophosphates, a new and improved methodology is still needed. Herein we demonstrate simple-to-fabricate chemiresistive gas sensors using conducting-polymer polypyrrole (PPy) nanotube transducers, which are chemically specific and capable of recognizing sub-ppb concentrations (ca. 0.5 ppb) of dimethyl methylphosphonate (DMMP), a simulant of nerve agent sarin. Interestingly, the introduction of carboxylic groups on the surface of PPy nanotube transistors resulted in enhanced sensitivity to DMMP via intermolecular hydrogen bonding. Furthermore, it was found that the sensitivity of the nanotube transducer depended on the degree of the carboxylic group introduced. Finally, a sensor array composed of 5 different transducers including the carboxylated nanotubes exhibited excellent selectivity to DMMP in 16 vapor species.

  8. Carboxylic Acid-Functionalized Conducting-Polymer Nanotubes as Highly Sensitive Nerve-Agent Chemiresistors

    PubMed Central

    Kwon, Oh Seok; Park, Chul Soon; Park, Seon Joo; Noh, Seonmyeong; Kim, Saerona; Kong, Hye Jeong; Bae, Joonwon; Lee, Chang-Soo; Yoon, Hyeonseok

    2016-01-01

    Organophosphates are powerful inhibitors of acetylcholinesterase, which is critical to nerve function. Despite continuous research for detecting the highly toxic organophosphates, a new and improved methodology is still needed. Herein we demonstrate simple-to-fabricate chemiresistive gas sensors using conducting-polymer polypyrrole (PPy) nanotube transducers, which are chemically specific and capable of recognizing sub-ppb concentrations (ca. 0.5 ppb) of dimethyl methylphosphonate (DMMP), a simulant of nerve agent sarin. Interestingly, the introduction of carboxylic groups on the surface of PPy nanotube transistors resulted in enhanced sensitivity to DMMP via intermolecular hydrogen bonding. Furthermore, it was found that the sensitivity of the nanotube transducer depended on the degree of the carboxylic group introduced. Finally, a sensor array composed of 5 different transducers including the carboxylated nanotubes exhibited excellent selectivity to DMMP in 16 vapor species. PMID:27650635

  9. Large-area irradiated low-level laser effect in a biodegradable nerve guide conduit on neural regeneration of peripheral nerve injury in rats.

    PubMed

    Shen, Chiung-Chyi; Yang, Yi-Chin; Liu, Bai-Shuan

    2011-08-01

    This study used a biodegradable composite containing genipin-cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles (genipin-gelatin-tricalcium phosphate, GGT), developed in a previous study, as a nerve guide conduit. The aim of this study was to analyse the influence of a large-area irradiated aluminium-gallium-indium phosphide (AlGaInP) diode laser (660 nm) on the neural regeneration of the transected sciatic nerve after bridging the GGT nerve guide conduit in rats. The animals were divided into two groups: group 1 comprised sham-irradiated controls and group 2 rats underwent low-level laser (LLL) therapy. A compact multi-cluster laser system with 20 AlGaInP laser diodes (output power, 50mW) was applied transcutaneously to the injured peripheral nerve immediately after closing the wound, which was repeated daily for 5 min for 21 consecutive days. Eight weeks after implantation, walking track analysis showed a significantly higher sciatic function index (SFI) score (P<0.05) and better toe spreading development in the laser-treated group than in the sham-irradiated control group. For electrophysiological measurement, both the mean peak amplitude and nerve conduction velocity of compound muscle action potentials (CMAPs) were higher in the laser-treated group than in the sham-irradiated group. The two groups were found to be significantly different during the experimental period (P<0.005). Histomorphometric assessments revealed that the qualitative observation and quantitative analysis of the regenerated nerve tissue in the laser-treated group were superior to those of the sham-irradiated group. Thus, the motor functional, electrophysiologic and histomorphometric assessments demonstrate that LLL therapy can accelerate neural repair of the corresponding transected peripheral nerve after bridging the GGT nerve guide conduit in rats.

  10. In vivo regeneration of rat sciatic nerve in a double-halved stitch-less guide: a pilot-study.

    PubMed

    Merolli, A; Rocchi, L; Catalano, F; Planell, J; Engel, E; Martinez, E; Sbernardori, M C; Marceddu, S; Leali, P Tranquilli

    2009-01-01

    It is about 20 years that tubular nerve guides have been introduced into clinical practice as a reliable alternative to autograft, in gaps not-longer-than 20 mm, bringing the advantage of avoiding donor site sacrifice and morbidity. There are limitations in the application of tubular guides. First, tubular structure in itself makes surgical implantation difficult; second, stitch sutures required to secure the guide may represent a site of unfavorable fibroblastic reaction; third, maximum length and diameter of the guide correlate with the occurrence of a poorer central vascularization of regenerated nerve. We report on the in vivo testing of a new concept of nerve-guide (named NeuroBox) which is double-halved, not-degradable, rigid, and does not require any stitch to be held in place, employing acrylate glue instead. Five male Wistar rats had the new guide implanted in a 4-mm sciatic nerve defect; two guides incorporated a surface constituted of microtrenches aligned longitudinally. Further five rats had the 4-mm gap left without repair. Contralateral intact nerves were used as controls. After 2 months, nerve regeneration occurred in all animals treated by the NeuroBox; fine blood vessels were well represented. There was no regeneration in the un-treated animals. Even if the limited number of animals does not allow to draw definitive conclusions, some result can be highlighted: an easy surgical technique was associated with the box-shaped guide and acrylate glue was easily applied; an adequate intraneural vascularization was found concurrently with the regeneration of the nerve and no adverse fibroblastic proliferation was present.

  11. Retrocrural splanchnic nerve alchohol neurolysis with a CT-guided anterior transaortic approach

    SciTech Connect

    Fields, S.

    1996-01-01

    Retrocrural splanchnic nerve alcohol neurolysis with a CT-guided anterior transonic approach, a new method for splanchnic block alleviation of chronic abdominal pain, is described. Ten patients with chronic abdominal pain requiring narcotic treatment, six with pancreatic carcinoma, one with gastric carcinoma, two with chronic pancreatitis, and one with pain of unknown etiology, were referred for splanchnic nerve neurolysis. With CT guidance, a 20 gauge needle was placed through the aorta into the retrocrural space at T11-T12, and 5-15 ml 96% alcohol was injected into the retrocrural space. Following the procedure, 6 of 10 patients were pain free, 2 patients had temporary pain relief, and 2 patients were without response. There were no significant complications. CT-guided anterior transaortic retrocrural splanchnic nerve alcohol neurolysis is technically feasible, easier to perform than the classic posterolateral approach, and may have less risk of complications. The success rate in this initial trial was reasonable and, therefore, this technique provides an additional method for the treatment of abdominal pain. 12 refs., 2 figs.

  12. Nerve growth factor-immobilized polypyrrole: Bioactive electrically conducting polymer for enhanced neurite extension

    PubMed Central

    Gomez, Natalia; Schmidt, Christine E.

    2010-01-01

    Biomaterials that present multiple stimuli are attractive for a number of biomedical applications. In particular, electrical and biological cues are important factors to include in interfaces with neurons for applications such as nerve conduits and neural probes. Here, we report the combination of these two stimuli, by immobilizing nerve growth factor (NGF) on the surface of the electrically conducting polymer polypyrrole (PPy). NGF was immobilized using an intermediate linker provided by a layer of polyallylamine conjugated to an arylazido functional group. Upon exposure to UV light and activation of the azido groups, NGF was fixed to the substrate. Three different surface concentrations were obtained (0.21–0.98 ng/mm2) and similar levels of neurite extension were observed on immobilized NGF as with soluble NGF. Additionally, electrical stimulation experiments were conducted with the modified polymer and revealed a 50% increase in neurite outgrowth in PC12 cells compared to experiments without electrical stimulation. This novel modification of PPy provides both electrical and biological stimulation, by presenting tethered growth factors and only producing a small decrease in the material's properties (conductivity ~10 S cm−1) when compared to other modification techniques (conductivity ~10−3–10−6 S cm−1. PMID:17111407

  13. [Ultrasound-guided cutaneous intercostal branches nerves block: A good analgesic alternative for gallbladder open surgery].

    PubMed

    Fernández Martín, M T; López Álvarez, S; Mozo Herrera, G; Platero Burgos, J J

    2015-12-01

    Laparoscopic cholecystectomy has become the standard treatment for gallbladder diseases. However, there are still some patients for whom conversion to open surgery is required. This surgery can produce significant post-operative pain. Opioids drugs have traditionally been used to treat this pain, but side effects have led to seeking alternatives (plexus, nerve or fascia blocks or wound). The cases are presented of 4 patients subjected to ultrasound-guided intercostal branches blocks in the mid-axillary line from T6 to T12 with levobupivacaine as an analgesic alternative in open surgery of gallbladder, with satisfactory results.

  14. Electrospun Nerve Guide Scaffold of Poly (ε-caprolactone)/Collagen/Nano-Bioglass: An in-vitro Study in Peripheral Nerve Tissue Engineering.

    PubMed

    Mohamadi, Forouzan; Ebrahimi-Barough, Somayeh; Nourani, Mohammad Reza; Derakhshan, Mohammad Ali; Goodarzi, Vahabodin; Nazockdast, Mohammad Sadegh; Farokhi, Mehdi; Tajerian, Roksana; Faridi Majidi, Reza; Ai, Jafar

    2017-03-21

    In among of various methods, nerve tissue engineering (NTE) is one of the applicable methods to reconstruct damaged nerve tissues. Electrospinning technique and biomaterials are often considered to fabricate fibrous tissue engineered conduits which have great similarity to the extracellular matrix on fiber structure. Polymer blending is one of the most effective methods for production of new materials with outstanding features. In this research, conduit structures as main part of the peripheral nerve regeneration based on polymer blend nanocomposites PCL/Collagen/NBG (poly (ε-caprolactone)/Collagen/nano bioglass) were manufactured by electrospinning technique. The various properties of electrospun mats were investigated by using contact angle, tensile, degradation time, porosity, scanning electron microscopy (SEM), Fourier-transfer infrared (FTIR), and wide-angle X-ray scattering (WAXS). The SEM analysis was shown that size range and average pore size of polymer blend nanocomposite nanofibers were about 250-400 nm and 0.7µm respectively with an optimum porosity of 62.5%. The XRD result was shown that synthesized nanoparticles of NBG had amorphous structures. Also, FTIR analysis indicated that good interaction between polymer-polymer macromolecules and polymer-particles. The Contact-angle and tensile tests analysis were indicated that electrospun webs showed good hydrophilicity and toughness properties. According to SEM, MTT assay and DAPI staining technique, the ability to support cell attachment and viability of samples were characterized. In vitro study indicated electrospun collagen/PCL/NBG nanofibrous conduit promoted Human Endometrial Stem cells (hEnSCs) adhesion and proliferation. This article is protected by copyright. All rights reserved.

  15. Successful Ultrasound-Guided Femoral Nerve Blockade and Catheterization in a Patient with Von Willebrand Disease

    PubMed Central

    DiStefano, Youmna E.; Lazar, Michael D.

    2015-01-01

    Peripheral nerve blockade (PNB) is superior to neuraxial anesthesia and/or opioid therapy for perioperative analgesia in total knee replacement (TKR). Evidence on the safety of PNB in patients with coagulopathy is lacking. We describe the first documented account of continuous femoral PNB for perioperative analgesia in a patient with Von Willebrand Disease (vWD). Given her history of opioid tolerance and after an informative discussion, a continuous femoral PNB was planned for in this 34-year-old female undergoing TKR. A Humate-P intravenous infusion was started and the patient was positioned supinely. Using sterile technique with ultrasound guidance, a Contiplex 18 Gauge Tuohy needle was advanced in plane through the fascia iliaca towards the femoral nerve. A nerve catheter was threaded through the needle and secured without complications. Postoperatively, a levobupivacaine femoral catheter infusion was maintained, and twice daily Humate-P intravenous infusions were administered for 48 hours; enoxaparin thromboprophylaxis was initiated thereafter. The patient was discharged uneventfully on postoperative day 4. Given documentation of delayed, unheralded bleeding from PNB in coagulopathic patients, we recommend individualized PNB in vWD patients. Multidisciplinary team involvement is required to guide factor supplementation and thromboprophylaxis, as is close follow-up to elicit signs of bleeding throughout the delayed postoperative period. PMID:26113995

  16. Successful Ultrasound-Guided Femoral Nerve Blockade and Catheterization in a Patient with Von Willebrand Disease.

    PubMed

    DiStefano, Youmna E; Lazar, Michael D

    2015-01-01

    Peripheral nerve blockade (PNB) is superior to neuraxial anesthesia and/or opioid therapy for perioperative analgesia in total knee replacement (TKR). Evidence on the safety of PNB in patients with coagulopathy is lacking. We describe the first documented account of continuous femoral PNB for perioperative analgesia in a patient with Von Willebrand Disease (vWD). Given her history of opioid tolerance and after an informative discussion, a continuous femoral PNB was planned for in this 34-year-old female undergoing TKR. A Humate-P intravenous infusion was started and the patient was positioned supinely. Using sterile technique with ultrasound guidance, a Contiplex 18 Gauge Tuohy needle was advanced in plane through the fascia iliaca towards the femoral nerve. A nerve catheter was threaded through the needle and secured without complications. Postoperatively, a levobupivacaine femoral catheter infusion was maintained, and twice daily Humate-P intravenous infusions were administered for 48 hours; enoxaparin thromboprophylaxis was initiated thereafter. The patient was discharged uneventfully on postoperative day 4. Given documentation of delayed, unheralded bleeding from PNB in coagulopathic patients, we recommend individualized PNB in vWD patients. Multidisciplinary team involvement is required to guide factor supplementation and thromboprophylaxis, as is close follow-up to elicit signs of bleeding throughout the delayed postoperative period.

  17. Ultrasonography-guided pulsed radiofrequency of sciatic nerve for the treatment of complex regional pain syndrome Type II

    PubMed Central

    Choi, Yi Hwa; Chang, Dong Jin; Hwang, Woon Suk; Chung, Jin Hwan

    2017-01-01

    Although the major mechanism of complex regional pain syndrome (CRPS) involves dysfunctional central or sympathetic nervous system activation, the peripheral nervous system also contributes significantly to its clinical manifestations. Pulsed radiofrequency (PRF) is a recently developed treatment option for neuropathic pain syndromes. Here, we report a case of CRPS Type II after a femur fracture and sciatic nerve injury, in which the pain was treated successfully with ultrasonography-guided selective sciatic nerve PRF application. PMID:28217060

  18. MRI-guided cryoablation of the posterior femoral cutaneous nerve for the treatment of neuropathy-mediated sitting pain.

    PubMed

    Joshi, Dharmdev H; Thawait, Gaurav K; Del Grande, Filippo; Fritz, Jan

    2017-03-15

    Neuropathy of the posterior femoral cutaneous nerve may manifest as pain and paresthesia in the skin over the inferior buttocks, posterior thigh, and popliteal region. Current treatment options include physical and oral pain therapy, perineural injections, and surgical neurectomy. Perineural steroid injections may provide short-term pain relief; however, to our knowledge, there is currently no minimally invasive denervation procedure for sustained pain relief that could serve as an alternative to surgical neurectomy. Percutaneous cryoablation of nerves is a minimally invasive technique that induces a sustained nerve conduction block through temporary freezing of the neural layers. It can result in long-lasting pain relief, but has not been described for the treatment of neuropathy-mediated PFCN pain. We report a technique of MR-guided cryoablation of the posterior femoral cutaneous nerve resulting in successful treatment of PFCN-mediated sitting pain. Cryoablation of the posterior femoral cutaneous nerve seems a promising, minimally invasive treatment option that deserves further investigation.

  19. US-Guided Femoral and Sciatic Nerve Blocks for Analgesia During Endovenous Laser Ablation

    SciTech Connect

    Yilmaz, Saim Ceken, Kagan; Alimoglu, Emel; Sindel, Timur

    2013-02-15

    Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency. During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1-10) was used for pain assessment. After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7). Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

  20. Characteristics and biocompatibility of a biodegradable genipin-cross-linked gelatin/β-tricalcium phosphate reinforced nerve guide conduit.

    PubMed

    Yang, Yi-Chin; Shen, Chiung-Chyi; Huang, Tsung-Bin; Chang, Shun-Hsung; Cheng, Hsu-Chen; Liu, Bai-Shuan

    2010-10-01

    To modulate the mechanical properties of nerve guide conduit for surgical manipulation, this study develops a biodegradable composite containing genipin cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles as a nerve guide material. The conduit was dark bluish and round with a rough and compact outer surface compared to the genipin cross-linked gelatin conduit (without β-tricalcium phosphate). Water uptake and swelling tests indicate that the conduit noticeably increases the stability in water, and the hydrated conduit does not collapse and stenose. The conduit has a sufficiently high level of mechanical properties to serve as a nerve guide. After subcutaneous implantation on the dorsal side of a rat, the degraded conduit only evokes a mild tissue response, and the formation of a very thin fibrous capsule surrounds the conduit. This paper assesses the effectiveness of the conduit as a guidance channel when we use it to repair a 10 mm gap in the rat's sciatic nerve. The experimental results show no gross inflammatory reactions of the peripheral nerve tissues at the implantation site in either group. In overall gross examination, the diameter of the intratubular and newly formed nerve fibers in the conduits exceeds that of the silicone tubes during the implantation period. The quantitative results indicate the superiority of the conduits over the silicone tubes. This study microscopically observes the nerve regeneration in the tissue section at the middle region of all implanted conduits. Therefore, the histomorphometric assessment demonstrates that the conduit could be a candidate for peripheral nerve repair.

  1. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate

    PubMed Central

    Sammet, Steffen; Partanen, Ari; Yousuf, Ambereen; Sammet, Christina L; Ward, Emily V; Wardrip, Craig; Niekrasz, Marek; Antic, Tatjana; Razmaria, Aria; Farahani, Keyvan; Sokka, Shunmugavelu; Karczmar, Gregory; Oto, Aytekin

    2015-01-01

    AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These

  2. Long-term regeneration of the rat sciatic nerve through a biodegradable poly(DL-lactide-epsilon-caprolactone) nerve guide: tissue reactions with focus on collagen III/IV reformation.

    PubMed

    Jansen, Koen; Meek, Marcel F; van der Werff, John F A; van Wachem, Pauline B; van Luyn, Marja J A

    2004-05-01

    Long-term studies on nerve-guide regeneration are scarce. Therefore, in rats, long-term (16 months) sciatic nerve regeneration through poly(DL-lactide-epsilon-caprolactone) [poly(DLLA-epsilon-CL)] nerve guides was studied and compared with the nonoperated control side. Poly(DLLA-epsilon-CL) degradation and possible long-term foreign body reaction against poly(DLLA-epsilon-CL) nerve guides, as well as the distribution of both collagen type III and IV were studied. In vivo poly(DLLA-epsilon-CL) studies have been performed before but not for such long time points; also, a detailed analysis of collagen III/IV has not been presented before. The results demonstrate that biodegradable poly(DLLA-epsilon-CL) nerve guides yield good nerve regeneration and collagen III/IV deposition relative to the anatomy of the control side. Regenerated nerve showed almost similar collagen type III/IV distribution patterns as compared with the nonoperated control side, although the delineation of matrix was clearer in the control side. The relative amount of collagen III and IV immunostaining in nerve cross-sections did not, however, differ between the control nerve tissue and the operated side after 16 months. After 16 months of implantation, however, some very small fragments of biomaterial could still be found on the edge of the epineurium of the regenerated nerve, indicating remnants of a secondary foreign body reaction. The biomaterial fragments and foreign body reaction did not influence the nerve regeneration process after 16 months. Biodegradable poly(DLLA-epsilon-CL) nerve guides are useful for long-term bridging of short peripheral nerve gaps.

  3. Guide wire extension for shape memory polymer occlusion removal devices

    DOEpatents

    Maitland, Duncan J.; Small, IV, Ward; Hartman, Jonathan

    2009-11-03

    A flexible extension for a shape memory polymer occlusion removal device. A shape memory polymer instrument is transported through a vessel via a catheter. A flexible elongated unit is operatively connected to the distal end of the shape memory polymer instrument to enhance maneuverability through tortuous paths en route to the occlusion.

  4. Feasibility, repeatability, and safety of ultrasound-guided stimulation of the first cervical nerve at the alar foramen in horses.

    PubMed

    Mespoulhès-Rivière, Céline; Brandenberger, Olivier; Rossignol, Fabrice; Robert, Céline; Perkins, Justin D; Marie, Jean-Paul; Ducharme, Norm

    2016-11-01

    OBJECTIVE To develop and assess the feasibility, repeatability, and safety of an ultrasound-guided technique to stimulate the first cervical nerve (FCN) at the level of the alar foramen of the atlas of horses. ANIMALS 4 equine cadavers and 6 clinically normal Standardbreds. PROCEDURES In each cadaver, the FCN pathway was determined by dissection, and any anastomosis between the first and second cervical nerves was identified. Subsequently, each of 6 live horses underwent a bilateral ultrasound-guided stimulation of the FCN at the alar foramen 3 times at 3-week intervals. After each procedure, horses were examined daily for 5 days. RESULTS In each cadaver, the FCN passed through the alar foramen; a communicating branch between the FCN and the accessory nerve and anastomoses between the ventral branches of the FCN and second cervical nerve were identified. The anastomoses were located in the upper third of the FCN pathway between the wing of the atlas and the nerve's entry in the omohyoideus muscle. Successful ultrasound-guided electrical stimulation was confirmed by twitching of the ipsilateral omohyoideus muscle in all 6 live horses; this finding was observed bilaterally during each of the 3 experimental sessions. No complications developed at the site of stimulation. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ultrasound-guided stimulation of the FCN at the alar foramen appears to be a safe and straightforward procedure in horses. The procedure may have potential for use in horses with naturally occurring recurrent laryngeal neuropathy to assess reinnervation after FCN transplantation or nerve-muscle pedicle implantation in the cricoarytenoideus dorsalis muscle.

  5. Presentation of Neurolytic Effect of 10% Lidocaine after Perineural Ultrasound Guided Injection of a Canine Sciatic Nerve: A Pilot Study

    PubMed Central

    Asif, Asma; Kataria, Sandeep

    2016-01-01

    Background Phenol and alcohol have been used to ablate nerves to treat pain but are not specific for nerves and can damage surrounding soft tissue. Lidocaine at concentrations > 8% injected intrathecal in the animal model has been shown to be neurotoxic. Tests the hypothesis that 10% lidocaine is neurolytic after a peri-neural blockade in an ex vivo experiment on the canine sciatic nerve. Methods Under ultrasound, one canine sciatic nerve was injected peri-neurally with 10 cc saline and another with 10 cc of 10% lidocaine. After 20 minutes, the sciatic nerve was dissected with gross inspection. A 3 cm segment was excised and preserved in 10% buffered formalin fixative solution. Both samples underwent progressive dehydration and infusion of paraffin after which they were placed on paraffin blocks. The sections were cut at 4 µm and stained with hemoxylin and eosin. Microscopic review was performed by a pathologist from Henry Ford Hospital who was blinded to which experimental group each sample was in. Results The lidocaine injected nerve demonstrated loss of gross architecture on visual inspection while the saline injected nerve did not. No gross changes were seen in the surrounding soft tissue seen in either group. The lidocaine injected sample showed basophilic degeneration with marked cytoplasmic vacuolation in the nerve fibers with separation of individual fibers and endoneurial edema. The saline injected sample showed normal neural tissue. Conclusions Ten percent lidocaine causes rapid neurolytic changes with ultrasound guided peri-neural injection. The study was limited by only a single nerve being tested with acute exposure. PMID:27413480

  6. Comparison of three techniques for ultrasound-guided femoral nerve catheter insertion: A randomized, blinded trial

    PubMed Central

    Farag, Ehab; Atim, Abdulkadir; Ghosh, Raktim; Bauer, Maria; Sreenivasalu, Thilak; Kot, Michael; Kurz, Andrea; Dalton, Jarrod E.; Mascha, Edward J.; Mounir-Soliman, Loran; Zaky, Sherif; Esa, Wael Ali Sakr; Udeh, Belinda L.; Barsoum, Wael; Sessler, Daniel I.

    2014-01-01

    Background Ultrasound guidance for continuous femoral perineural catheters may be supplemented by electrical stimulation through a needle or through a stimulating catheter. We tested the primary hypothesis that ultrasound guidance alone is noninferior on both postoperative pain scores and opioid requirement and superior on at least one of the two. Secondarily, we compared all interventions on insertion time and incremental cost. Methods Patients having knee arthroplasty with femoral nerve catheters were randomly assigned to catheter insertion guided by: 1) ultrasound alone (n=147); 2) ultrasound and electrical stimulation through the needle (n=152); or, 3) ultrasound and electrical stimulation through both the needle and catheter (n=138). Noninferiority between any two interventions was defined for pain as no more than 0.5 points worse on a 0–10 Verbal Response Scale (VRS) scale and for opioid consumption as no more than 25% greater than the mean. Results The stimulating needle group was significantly noninferior to the stimulating catheter (difference (95% CI) in mean VRS pain score [stimulating needle versus stimulating catheter] of −0.16 (−0.61, 0.29), P<0.001; percent difference in mean IV morphine equivalent dose of −5% (−25%, 21%), P=0.002) and to ultrasound only (difference in mean VRS pain score of −0.28 (−0.72, 0.16), P<0.001; percent difference in mean IV morphine equivalent dose of −2% (−22%, 25%), P=0.006). In addition, the use of ultrasound alone for femoral nerve catheter insertion was faster and cheaper than the other two methods. Conclusion Ultrasound guidance alone without adding either stimulating needle or needle/catheter combination thus appears to be the best approach to femoral perineural catheters. PMID:24758775

  7. Management of pudendal neuralgia using ultrasound-guided pulsed radiofrequency: a report of two cases and discussion of pudendal nerve block techniques.

    PubMed

    Hong, Myong-Joo; Kim, Yeon-Dong; Park, Jeong-Ki; Hong, Hyon-Joo

    2016-04-01

    Pudendal neuralgia is characterized by chronic pain or discomfort in the area innervated by the pudendal nerve, with no obvious cause. A successful pudendal nerve block is crucial for the diagnosis of pudendal neuralgia. Blind or fluoroscopy-guided pudendal nerve blocks have been conventionally used for diagnosis and treatment; however, ultrasound-guided pudendal nerve blocks were also reported recently. With regard to the achievement of long-term effects, although pulsed radiofrequency performed under fluoroscopic guidance has been reported, that performed under ultrasound guidance is not well reported. This report describes two cases of pudendal neuralgia that were successfully managed using ultrasound-guided pulsed radiofrequency and presents a literature review of pudendal nerve block techniques. However, in the management of chronic neuropathic pain, physicians should keep in mind that the placebo effect related to invasive approaches must not be neglected.

  8. Ultrasound-guided continuous femoral nerve block vs continuous fascia iliaca compartment block for hip replacement in the elderly

    PubMed Central

    Yu, Bin; He, Miao; Cai, Guang-Yu; Zou, Tian-Xiao; Zhang, Na

    2016-01-01

    Abstract Background: Continuous femoral nerve block and fascia iliaca compartment block are 2 traditional anesthesia methods in orthopedic surgeries, but it is controversial which method is better. The objective of this study was to compare the practicality, efficacy, and complications of the 2 modalities in hip replacement surgery in the elderly and to assess the utility of a novel cannula-over-needle set. Methods: In this prospective, randomized controlled clinical investigation, 60 elderly patients undergoing hip replacement were randomly assigned to receive either continuous femoral nerve block or continuous fascia iliaca compartment block. After ultrasound-guided nerve block, all patients received general anesthesia for surgery and postoperative analgesia through an indwelling cannula. Single-factor analysis of variance was used to compare the outcome variables between the 2 groups. Results: There was a significant difference between the 2 groups in the mean visual analog scale scores (at rest) at 6 hours after surgery: 1.0 ± 1.3 in the femoral nerve block group vs 0.5 ± 0.8 in the fascia iliaca compartment block group (P < 0.05). The femoral nerve block group had better postoperative analgesia on the medial aspect of the thigh, whereas the fascia iliaca compartment block group had better analgesia on the lateral aspect of the thigh. There were no other significant differences between the groups. Conclusions: Both ultrasound-guided continuous femoral nerve block and fascia iliaca compartment block with the novel cannula-over-needle provide effective anesthesia and postoperative analgesia for elderly hip replacement patients. PMID:27759633

  9. Reduction in mechanical allodynia in complex regional pain syndrome patients with ultrasound-guided pulsed radiofrequency treatment of the superficial peroneal nerve

    PubMed Central

    Chae, Won Soek; Kim, Sang Hyun; Cho, Sung Hwan; Lee, Mi Sun

    2016-01-01

    The superficial peroneal nerve is vulnerable to damage from ankle sprain injuries and fractures as well as surgery to this region. And it is also one of the most commonly involved nerves in complex regional pain syndrome type II in the foot and ankle region. We report two cases of ultrasound-guided pulsed radiofrequency treatment of superficial peroneal nerve for reduction of allodynia in CRPS patients. PMID:27738506

  10. Bioactive glass/polymer composites for bone and nerve repair and regeneration

    NASA Astrophysics Data System (ADS)

    Mohammadkhah, Ali

    Bioactive glasses have several attractive properties in hard and soft tissue repair but their brittleness limited their use, as scaffolding materials, for applications in load-bearing hard tissue repair. At the same time, because of their bioactive properties, they are being studied more often for soft tissue repair. In the present work, a new glass/polymer composite scaffold was developed for the repair of load-bearing bones with high flexural strength and without brittle behavior. The new composites have 2.5 times higher flexural strength and ˜100 times higher work of fracture (without catastrophic failure) compared to a similar bare glass scaffold. Also the use of two known bioactive glasses (13-93-B3 and 45S5) was investigated in developing glass/Poly(epsilon-caprolactone) (PCL) composite films for peripheral nerve repair. It was found that a layer of globular hydroxyapatite (HA) formed on both sides of the composites. The borate glass in the composites was fully reacted in SBF and different ions were released into the solution. The addition of bioactive glass particles to the PCL lowered its elastic modulus and yield strength, but the composites remained intact after the 14 day period in SBF at 37°C. Finally, in an effort to design a better bioactive glass, new borosilicate glass compositions were developed that possess advantages of borate and silicate bioactive glasses at the same time. It was found that replacing small amounts of B2O3 with SiO2 improved glass formation, resistance to nucleation and crystallization, and increased the release rate of boron and silicon in vitro. This new borosilicate glass could be a good alternative to existing silicate and borate bioactive glasses.

  11. Photo-crosslinked poly(epsilon-caprolactone fumarate) networks for guided peripheral nerve regeneration: material properties and preliminary biological evaluations.

    PubMed

    Wang, Shanfeng; Yaszemski, Michael J; Knight, Andrew M; Gruetzmacher, James A; Windebank, Anthony J; Lu, Lichun

    2009-06-01

    In an effort to achieve suitable biomaterials for peripheral nerve regeneration, we present a material design strategy of combining a crystallite-based physical network and a crosslink-based chemical network. Biodegradable polymer disks and conduits have been fabricated by photo-crosslinking three poly(epsilon-caprolactone fumarate)s (PCLF530, PCLF1250, and PCLF2000), which were synthesized from the precursor poly(epsilon-caprolactone) (PCL) diols with nominal molecular weights of 530, 1250, and 2000 g mol(-1), respectively. Thermal properties such as glass transition temperature (T(g)), melting temperature (T(m)), and crystallinity of photo-crosslinked PCLFs were examined and correlated with their rheological and mechanical properties. Furthermore, in vitro degradation of uncrosslinked and crosslinked PCLFs in PBS crosslinked PCLFs in 1 N NaOH aqueous solution at 37 degrees C was studied. In vitro cytocompatibility, attachment, and proliferation of Schwann cell precursor line SPL201 cells on three PCLF networks were investigated. Crosslinked PCLF2000 with the highest crystallinity and mechanical properties was found to best support cell attachment and proliferation. Using a new photo-crosslinking method, single-lumen crosslinked PCLF nerve conduits without defects were fabricated in a glass mold. Crosslinked PCLF2000 nerve conduits were selected for evaluation in a 1cm gap rat sciatic nerve model. Histological evaluation demonstrated that the material was biocompatible with sufficient strength to hold sutures in place after 6 and 17 weeks of implantation. Nerve cable with myelinated axons was found in the crosslinked PCLF2000 nerve conduit.

  12. Intramuscular nerve distribution patterns of anterior forearm muscles in children: a guide for botulinum toxin injection.

    PubMed

    Yang, Fangjiu; Zhang, Xiaoming; Xie, Xiadan; Yang, Shengbo; Xu, Yan; Xie, Peng

    2016-01-01

    Botulinum toxin (BoNT) can relieve muscle spasticity by blocking axon terminals acetylcholine release at the motor endplate (MEP) and is the safest and most effective agent for the treatment of muscle spasticity in children with cerebral palsy. In order to achieve maximum effect with minimum effective dose of BoNT, one needs to choose an injection site as near to the MEP zone as possible. This requires a detailed understanding about the nerve terminal distributions within the muscles targeted for BoNT injection. This study focuses on BoNT treatment in children with muscle spasms caused by cerebral palsy. Considering the differences between children and adults in anatomy, we used child cadavers and measured both the nerve entry points and nerve terminal sense zones in three deep muscles of the anterior forearm: flexor digitorum profundus (FDP), flexor pollicis longus (FPL), and pronator quadratus (PQ). We measured the nerve entry points by using the forearm midline as a reference and demonstrated intramuscular nerve terminal dense zones by using a modified Sihler's nerve staining technique. The locations of the nerve entry points and that of the nerve terminal dense zones in the muscles were compared. We found that all nerve entry points are away from the corresponding intramuscular nerve terminal dense zones. Simply selecting nerve entry points as the sites for BoNT injection may not be an optimal choice for best effects in blocking muscle spasm. We propose that the location of the nerve terminal dense zones in each individual muscle should be used as the optimal target sites for BoNT injection when treating muscle spasms in children with cerebral palsy.

  13. Intramuscular nerve distribution patterns of anterior forearm muscles in children: a guide for botulinum toxin injection

    PubMed Central

    Yang, Fangjiu; Zhang, Xiaoming; Xie, Xiadan; Yang, Shengbo; Xu, Yan; Xie, Peng

    2016-01-01

    Botulinum toxin (BoNT) can relieve muscle spasticity by blocking axon terminals acetylcholine release at the motor endplate (MEP) and is the safest and most effective agent for the treatment of muscle spasticity in children with cerebral palsy. In order to achieve maximum effect with minimum effective dose of BoNT, one needs to choose an injection site as near to the MEP zone as possible. This requires a detailed understanding about the nerve terminal distributions within the muscles targeted for BoNT injection. This study focuses on BoNT treatment in children with muscle spasms caused by cerebral palsy. Considering the differences between children and adults in anatomy, we used child cadavers and measured both the nerve entry points and nerve terminal sense zones in three deep muscles of the anterior forearm: flexor digitorum profundus (FDP), flexor pollicis longus (FPL), and pronator quadratus (PQ). We measured the nerve entry points by using the forearm midline as a reference and demonstrated intramuscular nerve terminal dense zones by using a modified Sihler’s nerve staining technique. The locations of the nerve entry points and that of the nerve terminal dense zones in the muscles were compared. We found that all nerve entry points are away from the corresponding intramuscular nerve terminal dense zones. Simply selecting nerve entry points as the sites for BoNT injection may not be an optimal choice for best effects in blocking muscle spasm. We propose that the location of the nerve terminal dense zones in each individual muscle should be used as the optimal target sites for BoNT injection when treating muscle spasms in children with cerebral palsy. PMID:28078019

  14. A standardized method for 4D ultrasound-guided peripheral nerve blockade and catheter placement.

    PubMed

    Clendenen, N J; Robards, C B; Clendenen, S R

    2014-01-01

    We present a standardized method for using four-dimensional ultrasound (4D US) guidance for peripheral nerve blocks. 4D US allows for needle tracking in multiple planes simultaneously and accurate measurement of the local anesthetic volume surrounding the nerve following injection. Additionally, the morphology and proximity of local anesthetic spread around the target nerve is clearly seen with the described technique. This method provides additional spatial information in real time compared to standard two-dimensional ultrasound.

  15. Automatic Segmentation and Probe Guidance for Real-Time Assistance of Ultrasound-Guided Femoral Nerve Blocks.

    PubMed

    Smistad, Erik; Iversen, Daniel Høyer; Leidig, Linda; Lervik Bakeng, Janne Beate; Johansen, Kaj Fredrik; Lindseth, Frank

    2017-01-01

    Ultrasound-guided regional anesthesia can be challenging, especially for inexperienced physicians. The goal of the proposed methods is to create a system that can assist a user in performing ultrasound-guided femoral nerve blocks. The system indicates in which direction the user should move the ultrasound probe to investigate the region of interest and to reach the target site for needle insertion. Additionally, the system provides automatic real-time segmentation of the femoral artery, the femoral nerve and the two layers fascia lata and fascia iliaca. This aids in interpretation of the 2-D ultrasound images and the surrounding anatomy in 3-D. The system was evaluated on 24 ultrasound acquisitions of both legs from six subjects. The estimated target site for needle insertion and the segmentations were compared with those of an expert anesthesiologist. Average target distance was 8.5 mm with a standard deviation of 2.5 mm. The mean absolute differences of the femoral nerve and the fascia segmentations were about 1-3 mm.

  16. Human Schwann Cells Seeded on a Novel Collagen-Based Microstructured Nerve Guide Survive, Proliferate, and Modify Neurite Outgrowth

    PubMed Central

    van Neerven, Sabien G. A.; Haastert-Talini, Kirsten; Tolba, René H.; Pallua, Norbert; Bozkurt, Ahmet

    2014-01-01

    A variety of new bioartificial nerve guides have been tested preclinically for their safety and nerve regeneration supporting properties. So far, only a limited number of biomaterials have been tested in humans since the step from preclinical work to a clinical application is challenging. We here present an in vitro model with human Schwann cells (hSCs) as an intermediate step towards clinical application of the nerve guide Perimaix, a collagen-based microstructured 3D scaffold containing numerous longitudinal guidance channels for directed axonal growth. hSCs were seeded onto different prototypes of Perimaix and cultivated for 14 days. hSC adhered to the scaffold, proliferated, and demonstrated healthy Schwann cell morphology (spindle shaped cell bodies, bipolar oriented processes) not only at the surface of the material, but also in the deeper layers of the scaffold. The general well-being of the cells was quantitatively confirmed by low levels of lactate dehydrogenase release into the culture medium. Moreover, conditioned medium of hSCs that were cultivated on Perimaix was able to modify neurite outgrowth from sensory dorsal root ganglion neurons. Overall these data indicate that Perimaix is able to provide a matrix that can promote the attachment and supports process extension, migration, and proliferation of hSC. PMID:24895582

  17. Separation of Armchair SWNTs by Using Polymer Conformation Guided Assembly

    DTIC Science & Technology

    2013-08-22

    30 Publications 36 Reference List 38     2 Introduction Single-walled carbon nanotubes (SWNTs) are among the most...with 12, the polymer 15 of linear geometry also forms the donor-acceptor complex resulting in enhanced interactions with graphene or carbon nanotubes .32...Band engineering of oxygen doped single-walled carbon nanotubes , NANOSCALE 2011, 6 2465-2468.  R. Gunasingh; C. Kah; K. Quarles; et al

  18. Novel use of biodegradable casein conduits for guided peripheral nerve regeneration.

    PubMed

    Hsiang, Shih-Wei; Tsai, Chin-Chuan; Tsai, Fuu-Jen; Ho, Tin-Yun; Yao, Chun-Hsu; Chen, Yueh-Sheng

    2011-11-07

    Recent advances in nerve repair technology have focused on finding more biocompatible, non-toxic materials to imitate natural peripheral nerve components. In this study, casein protein cross-linked with naturally occurring genipin (genipin-cross-linked casein (GCC)) was used for the first time to make a biodegradable conduit for peripheral nerve repair. The GCC conduit was dark blue in appearance with a concentric and round lumen. Water uptake, contact angle and mechanical tests indicated that the conduit had a high stability in water and did not collapse and cramped with a sufficiently high level of mechanical properties. Cytotoxic testing and terminal deoxynucleotidyl transferase dUTP nick-end labelling assay showed that the GCC was non-toxic and non-apoptotic, which could maintain the survival and outgrowth of Schwann cells. Non-invasive real-time nuclear factor-κB bioluminescence imaging accompanied by histochemical assessment showed that the GCC was highly biocompatible after subcutaneous implantation in transgenic mice. Effectiveness of the GCC conduit as a guidance channel was examined as it was used to repair a 10 mm gap in the rat sciatic nerve. Electrophysiology, labelling of calcitonin gene-related peptide in the lumbar spinal cord, and histology analysis all showed a rapid morphological and functional recovery for the disrupted nerves. Therefore, we conclude that the GCC can offer great nerve regeneration characteristics and can be a promising material for the successful repair of peripheral nerve defects.

  19. Fluoroscopically guided extraforaminal cervical nerve root blocks: analysis of epidural flow of the injectate with respect to needle tip position.

    PubMed

    Shipley, Kyle; Riew, K Daniel; Gilula, Louis A

    2014-02-01

    Study Design Retrospective evaluation of consecutively performed fluoroscopically guided cervical nerve root blocks. Objective To describe the incidence of injectate central epidural flow with respect to needle tip position during fluoroscopically guided extraforaminal cervical nerve root blocks (ECNRBs). Methods Between February 19, 2003 and June 11, 2003, 132 consecutive fluoroscopically guided ECNRBs performed with contrast media in the final injected material (injectate) were reviewed on 95 patients with average of 1.3 injections per patient. Fluoroscopic spot images documenting the procedure were obtained as part of standard quality assurance. An independent observer not directly involved in the procedures retrospectively reviewed the images, and the data were placed into a database. Image review was performed to determine optimal needle tip positioning for injectate epidural flow. Results Central epidural injectate flow was obtained in only 28.9% of injections with the needle tip lateral to midline of the lateral mass (zone 2). 83.8% of injectate went into epidural space when the needle tip was medial to midline of the lateral mass (zone 3). 100% of injectate flowed epidurally when the needle tip was medial to or at the medial cortex of the lateral mass (zone 4). There was no statistically significant difference with regards to central epidural flow and the needle tip position on lateral view. Conclusion To ensure central epidural flow with ECNRBs one must be prepared to pass the needle tip medial to midplane of the lateral mass or to medial cortex of the lateral mass. Approximately 16% of ECNRBs with needle tip medial to midline of the lateral mass did not flow into epidural space. One cannot claim a nerve block is an epidural block unless epidural flow of injectate is observed.

  20. Ultrasound-guided ilioinguinal and iliohypogastric nerve block, a comparison with the conventional technique: An observational study

    PubMed Central

    Khedkar, Sunita Milind; Bhalerao, Pradnya Milind; Yemul-Golhar, Shweta Rahul; Kelkar, Kalpana Vinod

    2015-01-01

    Background: The conventional technique of ilioinguinal and iliohypogastric nerve block may be associated with drug toxicity, block failure and needs large drug volume. The ultrasound-guided (USG) nerve block enables accurate needle positioning that may reduce the chances of drug toxicity, drug dose and block failure. Aim: In this study, we compared the onset and duration of the motor and sensory nerve block, the drug volume required and time to rescue analgesic between USG and conventional technique. Settings and Design: Sixty male patients aged between 18 and 60 years, belonging to American society of Anesthesiology I-II, scheduled for inguinal hernia repair were enrolled in this prospective study and were randomly allocated into two groups of thirty each by computerized method. Materials and Methods: Group A patients received hernia block by conventional method using 0.75% ropivacaine 15 ml, and Group B patients were given the block guided by ultrasound using 0.75% ropivacaine, till the nerves were surrounded on all sides by the drug. Statistical Analysis: The data were analyzed using two independent sample t-tests for demographic and hemodynamic parameters. Nonparametric test (Mann-Whitney U-test) was used to find the significance between visual analog scale. Results: There was significantly early onset of sensory block in Group B 14.03 ± 2.82 min as compared to Group A 15.57 ± 1.52 min (P = 0.047). The onset of motor block was also earlier in Group B 19.40 ± 2.85 min as compared to Group A 20.67 ± 1.90 min. The time to rescue analgesia was more in Group B 7.22 ± 0.97 h as compared to Group A 6.80 ± 0.70 h (P = 0.062). The volume of drug required was less with ultrasound guided block. Conclusions: Ultrasound-guided hernia block thus has the advantage of early onset, less dose requirement and increase in time to rescue analgesia. PMID:26240549

  1. Guided tissue fabrication from periosteum using preformed biodegradable polymer scaffolds.

    PubMed

    Thomson, R C; Mikos, A G; Beahm, E; Lemon, J C; Satterfield, W C; Aufdemorte, T B; Miller, M J

    1999-11-01

    A successful tissue engineering method for bone replacement would imitate natural bone graft by providing the essential elements for new bone formation using synthetic scaffolds, osteogenic cell populations, and bone induction factors. This is a study of the suitability of various formulations of poly(DL-lactic-co-glycolic acid) (PLGA) foams to provide a tissue conducting scaffold in an ovine model for bone flap fabrication. Three formulations were used of different copolymer ratio and molecular weight. Porous wafers of PLGA were stacked into rectangular chambers (volume 4 cm3) enclosed on five sides. Some chambers also contained autologous morcellized bone graft (MBG). The chambers were inserted with the open face adjacent to the cambium layer of the periosteum in rib beds of seven sheep and harvested after 8 weeks in vivo. Gross and histologic examination of the resulting tissue specimens demonstrated molded units of vascularized tissue generally conforming to the shape of the chambers and firmly attached to the periosteum. Polymer degradation appeared to occur by varying degrees based on polymer formulation. New bone formation was observed only in areas containing MBG. There was no evidence of significant inflammatory reaction or local tissue damage at 8 weeks. We conclude that a PLGA foam scaffold is (1) an efficient conductor of new tissue growth but not osteoinductive, (2) contributes to the shape of molded tissue, and (3) biocompatible when used in this model. Further studies are warranted to develop practical methods to deliver bone induction factors to the system to promote osseous tissue generation throughout the synthetic scaffold.

  2. Ultrasound-Guided Intercostobrachial Nerve Block for Intercostobrachial Neuralgia in Breast Cancer Patients: A Case Series.

    PubMed

    Wisotzky, Eric M; Saini, Vikramjeet; Kao, Cyrus

    2016-03-01

    This case series describes 3 cases in which ultrasound-guided intercostobrachial perineural injection was used for intercostobrachial neuralgia, a common cause of postmastectomy pain syndrome. All cases had undergone modified radical mastectomy with axillary lymph node dissection for breast cancer. Two cases developed axillary and unilateral chest wall pain. The third case initially presented with axillary pain and lateral shoulder pain 1 year out from radical mastectomy. After a cervical epidural steroid injection, her lateral shoulder pain resolved, but she continued to have residual chest wall paresthesia. It was at this time, we decided to treat with an intercostobrachial nerve perineural injection. Injury to the intercostobrachial nerve is thought to be a common cause of postmastectomy pain. In our case series, all patients had pain relief after the intercostobrachial perineural injection. There is a relative dearth of published information on the treatment of postmastectomy pain and more specifically intercostobrachial neuralgia. We review the anatomy of the intercostobrachial nerve and its variants, etiologies of intercostobrachial neuralgia, and current indications and methods of an intercostobrachial perineural injection.

  3. Functional recovery guided by an electrospun silk fibroin conduit after sciatic nerve injury in rats.

    PubMed

    Park, Sook Young; Ki, Chang Seok; Park, Young Hwan; Lee, Kwang Gill; Kang, Seok Woo; Kweon, Hae Yong; Kim, Hyun Jeong

    2015-01-01

    The aim of this study was to evaluate the regenerative capacity of a newly developed nerve guidance conduit using electrospun silk fibroin (SFNC) implanted in a 10-mm defect of the sciatic nerve in rats. After evaluating the physical properties and cytocompatibility of SFNC in vitro, rats were randomly allocated into three groups: defect only, autograft and SFNC. To compare motor function and abnormal sensation among groups, ankle stance angle (ASA) and severity of autotomy were observed for 10 weeks after injury. Immunostaining with axonal neurofilament (NF) and myelin basic protein (MBP) antibodies were performed to investigate regenerated nerve fibres inside SFNC. ASA increased significantly in the SFNC group at 1, 7 and 10 weeks after injury compared to the defect only group (p<0.05). At one week, mean ASA of the SFNC group was significantly higher than that of the autograft group (p<0.05). Onset and severity of autotomy decreased significantly in the SFNC group compared to other groups (p<0.05). Autotomy in the SFNC group started at 4 weeks and maximally reached toe level. However, the defect only and autograft groups first showed autotomy at 2 and 1 weeks following injury, respectively, and then reached the sole level. Well myelinated nerve fibres stained with NF and MBP were found inside SFNC. In conclusion, SFNC could be helpful in restoring motor function and preventing abnormal sensations after nerve injury.

  4. Novel CT-guided biopsy of isolated perineural spread of adenoid cystic carcinoma along the trigeminal nerve masquerading as chronic trigeminal neuropathy.

    PubMed

    Yong, Xian Zhang Eric; Dillon, Jonathan; Smith, Paul; Salinas-La Rosa, Cesar; Jhamb, Ashu

    2017-02-01

    The differential diagnoses for chronic peripheral neuropathy are broad and diagnosing a cause can be challenging. We present a case of isolated perineural spread of adenoid cystic carcinoma to the trigeminal nerve involving skull base foramina and Meckel's cave in the setting of chronic trigeminal neuropathy and no known prior malignancy. Computed tomography-guided core (CT) needle biopsy was needed to arrive at a diagnosis and a novel approach was required to obtain tissue from the trigeminal nerve lesion at foramen ovale.

  5. The reflectivity of carbon fiber reinforced polymer short circuit illuminated by guided microwaves

    NASA Astrophysics Data System (ADS)

    Bojovschi, A.; Scott, J.; Ghorbani, K.

    2013-09-01

    An investigation of the interaction between guided electromagnetic waves and carbon fibre reinforced polymer waveguide short circuits is presented. To determine the electromagnetic response of the composite waveguide short circuit, its anisotropic characteristics are considered. The reflection coefficients of the short circuit, at the reference plane, are about 0.98 over the whole 8 GHz to 12 GHz band. The results indicate the viability of carbon fiber based short circuits for lightweight waveguides.

  6. Development of chitosan-crosslinked nanofibrous PHBV guide for repair of nerve defects.

    PubMed

    Biazar, Esmaeil; Heidari Keshel, Saeed

    2014-12-01

    The aim of this study was to produce a chitosan-crosslinked nanofibrous biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nerve conduit. The artificial scaffold was designed by electrospinning method, and cross-linked with chitosan by chemical method. The scaffolds were evaluated by microscopic, physical, and mechanical analyses, and cell culture assays with Schwann cells. Results of analyses showed a good resilience and compliance with movement as a neural graft. Cellular experiments showed a better cell adhesion and growth inside the crosslinked nanofibrous scaffolds compared with un-crosslinked ones. This neural conduit appears to have the right organization for testing in vivo nerve tissue engineering studies.

  7. Polymer Coatings of Cochlear Implant Electrode Surface – An Option for Improving Electrode-Nerve-Interface by Blocking Fibroblast Overgrowth

    PubMed Central

    Hadler, C.; Aliuos, P.; Brandes, G.; Warnecke, A.; Bohlmann, J.; Dempwolf, W.; Menzel, H.; Lenarz, T.; Reuter, G.; Wissel, K.

    2016-01-01

    Overgrowth of connective tissue and scar formation induced by the electrode array insertion increase the impedance and, thus, diminish the interactions between neural probes as like cochlear implants (CI) and the target tissue. Therefore, it is of great clinical interest to modify the carrier material of the electrodes to improve the electrode nerve interface for selective cell adhesion. On one side connective tissue growth needs to be reduced to avoid electrode array encapsulation, on the other side the carrier material should not compromise the interaction with neuronal cells. The present in vitro-study qualitatively and quantitatively characterises the interaction of fibroblasts, glial cells and spiral ganglion neurons (SGN) with ultrathin poly(N,N-dimethylacrylamide) (PDMAA), poly(2-ethyloxazoline) (PEtOx) and poly([2-methacryloyloxy)ethyl]trimethylammoniumchlorid) (PMTA) films immobilised onto glass surfaces using a photoreactive anchor layer. The layer thickness and hydrophilicity of the polymer films were characterised by ellipsometric and water contact angle measurement. Moreover the topography of the surfaces was investigated using atomic force microscopy (AFM). The neuronal and non-neuronal cells were dissociated from spiral ganglions of postnatal rats and cultivated for 48 h on top of the polymer coatings. Immunocytochemical staining of neuronal and intermediary filaments revealed that glial cells predominantly attached on PMTA films, but not on PDMAA and PEtOx monolayers. Hereby, strong survival rates and neurite outgrowth were only found on PMTA, whereas PDMAA and PEtOx coatings significantly reduced the SG neuron survival and neuritogenesis. As also shown by scanning electron microscopy (SEM) SGN strongly survived and retained their differentiated phenotype only on PMTA. In conclusion, survival and neuritogenesis of SGN may be associated with the extent of the glial cell growth. Since PMTA was the only of the polar polymers used in this study bearing

  8. Rehabilitation, Using Guided Cerebral Plasticity, of a Brachial Plexus Injury Treated with Intercostal and Phrenic Nerve Transfers

    PubMed Central

    Dahlin, Lars B.; Andersson, Gert; Backman, Clas; Svensson, Hampus; Björkman, Anders

    2017-01-01

    Recovery after surgical reconstruction of a brachial plexus injury using nerve grafting and nerve transfer procedures is a function of peripheral nerve regeneration and cerebral reorganization. A 15-year-old boy, with traumatic avulsion of nerve roots C5–C7 and a non-rupture of C8–T1, was operated 3 weeks after the injury with nerve transfers: (a) terminal part of the accessory nerve to the suprascapular nerve, (b) the second and third intercostal nerves to the axillary nerve, and (c) the fourth to sixth intercostal nerves to the musculocutaneous nerve. A second operation—free contralateral gracilis muscle transfer directly innervated by the phrenic nerve—was done after 2 years due to insufficient recovery of the biceps muscle function. One year later, electromyography showed activation of the biceps muscle essentially with coughing through the intercostal nerves, and of the transferred gracilis muscle by deep breathing through the phrenic nerve. Voluntary flexion of the elbow elicited clear activity in the biceps/gracilis muscles with decreasing activity in intercostal muscles distal to the transferred intercostal nerves (i.e., corresponding to eighth intercostal), indicating cerebral plasticity, where neural control of elbow flexion is gradually separated from control of breathing. To restore voluntary elbow function after nerve transfers, the rehabilitation of patients operated with intercostal nerve transfers should concentrate on transferring coughing function, while patients with phrenic nerve transfers should focus on transferring deep breathing function. PMID:28316590

  9. Comparison of peripheral nerve stimulator versus ultrasonography guided axillary block using multiple injection technique

    PubMed Central

    Kumar, Alok; Sharma, DK; Sibi, Maj. E; Datta, Barun; Gogoi, Biraj

    2014-01-01

    Background: The established methods of nerve location were based on either proper motor response on nerve stimulation (NS) or ultrasound guidance. In this prospective, randomised, observer-blinded study, we compared ultrasound guidance with NS for axillary brachial plexus block using 0.5% bupivacaine with the multiple injection techniques. Methods: A total of 120 patients receiving axillary brachial plexus block with 0.5% bupivacaine, using a multiple injection technique, were randomly allocated to receive either NS (group NS, n = 60), or ultrasound guidance (group US, n = 60) for nerve location. A blinded observer recorded the onset of sensory and motor blocks, skin punctures, needle redirections, procedure-related pain and patient satisfaction. Results: The median (range) number of skin punctures were 2 (2–4) in group US and 3 (2–5) in group NS (P < 0.001). No differences were observed in the onset of sensory block in group NS (6.17 ± 1.22 min) and in group US (6.33 ± 0.48 min) (P = 0.16), and in onset of motor block (23.33 ± 1.26 min) in group US and (23.17 ± 1.79 min) in group NS; P > =0.27). Insufficient block was observed in three patient (5%) of group US and four patients (6.67%) of group NS (P > =0.35). Patient acceptance was similarly good in the two groups. Conclusion: Multiple injection axillary blocks with ultrasound guidance provided similar success rates and comparable incidence of complications as compared with NS guidance with 20 ml 0.5% bupivacaine. PMID:25624532

  10. Salicylic Acid-Based Polymers for Guided Bone Regeneration Using Bone Morphogenetic Protein-2

    PubMed Central

    Subramanian, Sangeeta; Mitchell, Ashley; Yu, Weiling; Snyder, Sabrina; Uhrich, Kathryn

    2015-01-01

    Bone morphogenetic protein-2 (BMP-2) is used clinically to promote spinal fusion, treat complex tibia fractures, and to promote bone formation in craniomaxillofacial surgery. Excessive bone formation at sites where BMP-2 has been applied is an established complication and one that could be corrected by guided tissue regeneration methods. In this study, anti-inflammatory polymers containing salicylic acid [salicylic acid-based poly(anhydride-ester), SAPAE] were electrospun with polycaprolactone (PCL) to create thin flexible matrices for use as guided bone regeneration membranes. SAPAE polymers hydrolyze to release salicylic acid, which is a nonsteroidal anti-inflammatory drug. PCL was used to enhance the mechanical integrity of the matrices. Two different SAPAE-containing membranes were produced and compared: fast-degrading (FD-SAPAE) and slow-degrading (SD-SAPAE) membranes that release salicylic acid at a faster and slower rate, respectively. Rat femur defects were treated with BMP-2 and wrapped with FD-SAPAE, SD-SAPAE, or PCL membrane or were left unwrapped. The effects of different membranes on bone formation within and outside of the femur defects were measured by histomorphometry and microcomputed tomography. Bone formation within the defect was not affected by membrane wrapping at BMP-2 doses of 12 μg or more. In contrast, the FD-SAPAE membrane significantly reduced bone formation outside the defect compared with all other treatments. The rapid release of salicylic acid from the FD-SAPAE membrane suggests that localized salicylic acid treatment during the first few days of BMP-2 treatment can limit ectopic bone formation. The data support development of SAPAE polymer membranes for guided bone regeneration applications as well as barriers to excessive bone formation. PMID:25813520

  11. Salicylic Acid-Based Polymers for Guided Bone Regeneration Using Bone Morphogenetic Protein-2.

    PubMed

    Subramanian, Sangeeta; Mitchell, Ashley; Yu, Weiling; Snyder, Sabrina; Uhrich, Kathryn; O'Connor, J Patrick

    2015-07-01

    Bone morphogenetic protein-2 (BMP-2) is used clinically to promote spinal fusion, treat complex tibia fractures, and to promote bone formation in craniomaxillofacial surgery. Excessive bone formation at sites where BMP-2 has been applied is an established complication and one that could be corrected by guided tissue regeneration methods. In this study, anti-inflammatory polymers containing salicylic acid [salicylic acid-based poly(anhydride-ester), SAPAE] were electrospun with polycaprolactone (PCL) to create thin flexible matrices for use as guided bone regeneration membranes. SAPAE polymers hydrolyze to release salicylic acid, which is a nonsteroidal anti-inflammatory drug. PCL was used to enhance the mechanical integrity of the matrices. Two different SAPAE-containing membranes were produced and compared: fast-degrading (FD-SAPAE) and slow-degrading (SD-SAPAE) membranes that release salicylic acid at a faster and slower rate, respectively. Rat femur defects were treated with BMP-2 and wrapped with FD-SAPAE, SD-SAPAE, or PCL membrane or were left unwrapped. The effects of different membranes on bone formation within and outside of the femur defects were measured by histomorphometry and microcomputed tomography. Bone formation within the defect was not affected by membrane wrapping at BMP-2 doses of 12 μg or more. In contrast, the FD-SAPAE membrane significantly reduced bone formation outside the defect compared with all other treatments. The rapid release of salicylic acid from the FD-SAPAE membrane suggests that localized salicylic acid treatment during the first few days of BMP-2 treatment can limit ectopic bone formation. The data support development of SAPAE polymer membranes for guided bone regeneration applications as well as barriers to excessive bone formation.

  12. Treatment of proximal hamstring tendinopathy-related sciatic nerve entrapment: presentation of an ultrasound-guided “Intratissue Percutaneous Electrolysis” application

    PubMed Central

    Mattiussi, Gabriele; Moreno, Carlos

    2016-01-01

    Summary Background Proximal Hamstring Tendinopathy-related Sciatic Nerve Entrapment (PHTrSNE) is a neuropathy caused by fibrosis interposed between the semimembranosus tendon and the sciatic nerve, at the level of the ischial tuberosity. Methods Ultrasound-guided Intratissue Percutaneous Electrolysis (US-guided EPI) involves galvanic current transfer within the treatment target tissue (fibrosis) via a needle 0.30 to 0.33 mm in diameter. The galvanic current in a saline solution instantly develops the chemical process of electrolysis, which in turn induces electrochemical ablation of fibrosis. In this article, the interventional procedure is presented in detail, and both the strengths and limits of the technique are discussed. Results US-guided EPI eliminates the fibrotic accumulation that causes PHTrSNE, without the semimembranosus tendon or the sciatic nerve being directly involved during the procedure. The technique is however of limited use in cases of compression neuropathy. Conclusion US-guided EPI is a technique that is quick to perform, minimally invasive and does not force the patient to suspend their activities (work or sports) to make the treatment effective. This, coupled to the fact that the technique is generally well-tolerated by patients, supports use of US-guided EPI in the treatment of PHTrSNE. PMID:27900300

  13. Ultrasound-Guided Femoral and Sciatic Nerve Blocks for Repair of Tibia and Fibula Fractures in a Bennett's Wallaby (Macropus rufogriseus)

    PubMed Central

    Campoy, Luis; Adami, Chiara

    2016-01-01

    Locoregional anesthetic techniques may be a very useful tool for the anesthetic management of wallabies with injuries of the pelvic limbs and may help to prevent capture myopathies resulting from stress and systemic opioids' administration. This report describes the use of ultrasound-guided femoral and sciatic nerve blocks in Bennett's wallaby (Macropus rufogriseus) referred for orthopaedic surgery. Ultrasound-guided femoral and sciatic nerve blocks were attempted at the femoral triangle and proximal thigh level, respectively. Whilst the sciatic nerve could be easily visualised, the femoral nerve could not be readily identified. Only the sciatic nerve was therefore blocked with ropivacaine, and methadone was administered as rescue analgesic. The ultrasound images were stored and sent for external review. Anesthesia and recovery were uneventful and the wallaby was discharged two days postoperatively. At the time of writing, it is challenging to provide safe and effective analgesia to Macropods. Detailed knowledge of the anatomy of these species is at the basis of successful locoregional anesthesia. The development of novel analgesic techniques suitable for wallabies would represent an important step forward in this field and help the clinicians dealing with these species to improve their perianesthetic management. PMID:27803817

  14. Assessment of in vivo behavior of polymer tube nerve grafts simultaneously with the peripheral nerve regeneration process using scanning electron microscopy technique.

    PubMed

    Szarek, Dariusz; Marycz, Krzysztof; Laska, Jadwiga; Bednarz, Paulina; Jarmundowicz, Włodzimierz

    2013-01-01

    In this study, scanning electron microscopy (SEM) has been applied for instantaneous assessment of processes occurring at the site of regenerating nerve. The technique proved to be especially useful when an artificial implant should have been observed but have not yet been extensively investigated before for assessment of nerve tissue. For in vivo studies, evaluation of implant's morphology and its neuroregenerative properties is of great importance when new prototype is developed. However, the usually applied histological techniques require separate and differently prepared samples, and therefore, the results are never a 100% comparable. In our research, we found SEM as a technique providing detailed data both on an implant behavior and the nerve regeneration process inside the implant. Observations were carried out during 12-week period on rat sciatic nerve injury model reconstructed with nerve autografts and different tube nerve grafts. Samples were analyzed with haematoxylin-eosin (HE), immunocytochemical staining for neurofillament and S-100 protein, SEM, TEM, and the results were compared. SEM studies enabled to obtain characteristic pictures of the regeneration process similarly to TEM and histological studies. Schwann cell transformation and communication as well as axonal outgrowth were identified, newly created and matured axons could be recognized. Concurrent analysis of biomaterial changes in the implant (degradation, collapsing of the tube wall, migration of alginate gel) was possible. This study provides the groundwork for further use of the described technique in the nerve regeneration studies.

  15. Feasibility Study on MR-Guided High-Intensity Focused Ultrasound Ablation of Sciatic Nerve in a Swine Model: Preliminary Results

    SciTech Connect

    Kaye, Elena A.; Gutta, Narendra Babu; Monette, Sebastien; Gulati, Amitabh Loh, Jeffrey; Srimathveeravalli, Govindarajan; Ezell, Paula C.; Erinjeri, Joseph P. Solomon, Stephen B. Maybody, Majid

    2015-08-15

    IntroductionSpastic patients often seek neurolysis, the permanent destruction of the sciatic nerve, for better pain management. MRI-guided high-intensity focused ultrasound (MRgHIFU) may serve as a noninvasive alternative to the prevailing, more intrusive techniques. This in vivo acute study is aimed at performing sciatic nerve neurolysis using a clinical MRgHIFU system.MethodsThe HIFU ablation of sciatic nerves was performed in swine (n = 5) using a HIFU system integrated with a 3 T MRI scanner. Acute lesions were confirmed using T1-weighted contrast-enhanced (CE) MRI and histopathology using hematoxylin and eosin staining. The animals were euthanized immediately following post-ablation imaging.ResultsReddening and mild thickening of the nerve and pallor of the adjacent muscle were seen in all animals. The HIFU-treated sections of the nerves displayed nuclear pyknosis of Schwann cells, vascular hyperemia, perineural edema, hyalinization of the collagenous stroma of the nerve, myelin sheet swelling, and loss of axons. Ablations were visible on CE MRI. Non-perfused volume of the lesions (5.8–64.6 cc) linearly correlated with estimated lethal thermal dose volume (4.7–34.2 cc). Skin burn adjacent to the largest ablated zone was observed in the first animal. Bilateral treatment time ranged from 55 to 138 min, and preparation time required 2 h on average.ConclusionThe acute pilot study in swine demonstrated the feasibility of a noninvasive neurolysis of the sciatic nerve using a clinical MRgHIFU system. Results revealed that acute HIFU nerve lesions were detectable on CE MRI, gross pathology, and histology.

  16. Extracellular matrix components in peripheral nerve regeneration.

    PubMed

    Gonzalez-Perez, Francisco; Udina, Esther; Navarro, Xavier

    2013-01-01

    Injured axons of the peripheral nerve are able to regenerate and, eventually, reinnervate target organs. However, functional recovery is usually poor after severe nerve injuries. The switch of Schwann cells to a proliferative state, secretion of trophic factors, and the presence of extracellular matrix (ECM) molecules (such as collagen, laminin, or fibronectin) in the distal stump are key elements to create a permissive environment for axons to grow. In this review, we focus attention on the ECM components and their tropic role in axonal regeneration. These components can also be used as molecular cues to guide the axons through artificial nerve guides in attempts to better mimic the natural environment found in a degenerating nerve. Most used scaffolds tested are based on natural molecules that form the ECM, but use of synthetic polymers and functionalization of hydrogels are bringing new options. Progress in tissue engineering will eventually lead to the design of composite artificial nerve grafts that may replace the use of autologous nerve grafts to sustain regeneration over long gaps.

  17. Topography-guided buckling of swollen polymer bilayer films into three-dimensional structures.

    PubMed

    Jeong, Joonwoo; Cho, Yigil; Lee, Su Yeon; Gong, Xingting; Kamien, Randall D; Yang, Shu; Yodh, A G

    2017-02-07

    Thin films that exhibit spatially heterogeneous swelling often buckle into the third dimension to minimize stress. These effects, in turn, offer a promising strategy to fabricate complex three-dimensional structures from two-dimensional sheets. Here we employ surface topography as a new means to guide buckling of swollen polymer bilayer films and thereby control the morphology of resulting three-dimensional objects. Topographic patterns are created on poly(dimethylsiloxane) (PDMS) films selectively coated with a thin layer of non-swelling parylene on different sides of the patterned films. After swelling in an organic solvent, various structures are formed, including half-pipes, helical tubules, and ribbons. We demonstrate these effects and introduce a simple geometric model that qualitatively captures the relationship between surface topography and the resulting swollen film morphologies. The model's limitations are also examined.

  18. Influence of cross-linking degree of a biodegradable genipin-cross-linked gelatin guide on peripheral nerve regeneration.

    PubMed

    Lu, Ming-Chin; Hsiang, Shih-Wei; Lai, Tung-Yuan; Yao, Chun-Hsu; Lin, Li-Yu; Chen, Yueh-Sheng

    2007-01-01

    We evaluated peripheral nerve regeneration using biodegradable genipin-cross-linked gelatin nerve conduits (GGCs) with three different cross-linking degrees, 24, 36 and 51%. Biocompatibility and biodegradability of the GGC and its efficiency as a guidance channel were examined based on the repair process of a 10-mm gap in the rat sciatic nerve. From this pilot study we concluded that GGCs with a mean cross-linking degree of 36% can ensure nerve regeneration with a more mature structure, as demonstrated by better developed epineural and perineural organisation and axonal development, as well as better-recovered electrophysiology with a relatively positive sciatic functional index and a shorter latency of the muscle action potential curve. Regenerated nerves in the GGCs with mean cross-linking degrees of 24 and 51% were less favourable, due to irritation caused by degradation material and compression by the remaining tube walls, respectively.

  19. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants Dimethylmethylphosphonate and Diisopropy

    NASA Astrophysics Data System (ADS)

    Hopkins, Alan R.; Lewis, Nathan S.

    2002-06-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black-organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m-3. These values are lower than the EC50 value for the nerve agents sarin (methylphosphonofluoridic acid, (1-methylethyl) ester) and soman, which have been established as equals 0.8 mg m-3. Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes in a laboratory air background. In addition, DMMP at 27 mg m-3 could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferents in the background ambient, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

  20. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants dimethylmethylphosphonate and diisopropylmethylphosponate.

    PubMed

    Hopkins, A R; Lewis, N S

    2001-03-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black/ organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m(-3). These values are lower than the EC50 value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 min) for the nerve agents sarin (methylphosphonofluoridic acid, 1-methylethyl ester) and soman (methylphosphonofluoridic acid, 1,2,2-trimethylpropyl ester), which has been established as approximately 0.8 mg m(-3). Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes (including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran) in a laboratory air background. In addition, DMMP at 27 mg m(-3) could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferences, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

  1. Polymer-drug compatibility: a guide to the development of delivery systems for the anticancer agent, ellipticine.

    PubMed

    Liu, Jubo; Xiao, Yuehua; Allen, Christine

    2004-01-01

    To establish a method for predicting polymer-drug compatibility as a means to guide formulation development, we carried out physicochemical analyses of polymer-drug pairs and compared the difference in total and partial solubility parameters of polymer and drug. For these studies, we employed a range of biodegradable polymers and the anticancer agent Ellipticine as the model drug. The partial and total solubility parameters for the polymer and drug were calculated using the group contribution method. Drug-polymer pairs with different enthalpy of mixing values were analyzed by physicochemical techniques including X-ray diffraction and Fourier transform infrared. Polymers identified to be compatible [i.e., polycaprolactone (PCL) and poly-beta-benzyl-L-aspartate (PBLA)] and incompatible [i.e., poly (d,l-lactide (PLA)], by the above mentioned methods, were used to formulate Ellipticine. Specifically, Ellipticine was loaded into PBLA, PCL, and PLA films using a solvent casting method to produce a local drug formulation; while, polyethylene oxide (PEO)-b-polycaprolactone (PCL) and PEO-b-poly (d,l-lactide) (PLA) copolymer micelles were prepared by both dialysis and dry down methods resulting in a formulation for systemic administration. The drug release profiles for all formulations and the drug loading efficiency for the micelle formulations were also measured. In this way, we compared formulation characteristics with predictions from physicochemical analyses and comparison of total and partial solubility parameters. Overall, a good correlation was obtained between drug formulation characteristics and findings from our polymer-drug compatibility studies. Further optimization of the PEO-b-PCL micelle formulation for Ellipticine was also performed.

  2. Improved perioperative analgesia with ultrasound-guided ilioinguinal/iliohypogastric nerve or transversus abdominis plane block for open inguinal surgery: a systematic review and meta-analysis of randomized controlled trials

    PubMed Central

    Wang, Yuexiang; Wu, Tao; Terry, Marisa J.; Eldrige, Jason S.; Tong, Qiang; Erwin, Patricia J.; Wang, Zhen; Qu, Wenchun

    2016-01-01

    [Purpose] Ultrasound-guided ilioinguinal/iliohypogastric (II/IH) nerve and transversus abdominis plane (TAP) blocks have been increasingly utilized in patients for perioperative analgesia. We conducted this meta-analysis to evaluate the clinical efficacy of ultrasound-guided II/IH nerve or TAP blocks for perioperative analgesia in patients undergoing open inguinal surgery. [Subjects and Methods] A systematic search was conducted of 7 databases from the inception to March 5, 2015. Randomized controlled trials (RCTs) comparing the clinical efficacy of ultrasound-guided vs. landmark-based techniques to perform II/IH nerve and TAP blocks in patients with open inguinal surgery were included. We constructed random effects models to pool the standardized mean difference (SMD) for continuous outcomes and the odds ratio (OR) for dichotomized outcomes. [Results] Ultrasound-guided II/IH nerve or TAP blocks were associated with a reduced use of intraoperative additional analgesia and a significant reduction of pain scores during day-stay. The use of rescue drugs was also significantly lower in the ultrasound-guided group. [Conclusion] The use of ultrasound-guidance to perform an II/IH nerve or a TAP block was associated with improved perioperative analgesia in patients following open inguinal surgery compared to landmark-based methods. PMID:27134411

  3. Chronic recording of regenerating VIIIth nerve axons with a sieve electrode

    NASA Technical Reports Server (NTRS)

    Mensinger, A. F.; Anderson, D. J.; Buchko, C. J.; Johnson, M. A.; Martin, D. C.; Tresco, P. A.; Silver, R. B.; Highstein, S. M.

    2000-01-01

    A micromachined silicon substrate sieve electrode was implanted within transected toadfish (Opsanus tau) otolith nerves. High fidelity, single unit neural activity was recorded from seven alert and unrestrained fish 30 to 60 days after implantation. Fibrous coatings of genetically engineered bioactive protein polymers and nerve guide tubes increased the number of axons regenerating through the electrode pores when compared with controls. Sieve electrodes have potential as permanent interfaces to the nervous system and to bridge missing connections between severed or damaged nerves and muscles. Recorded impulses might also be amplified and used to control prosthetic devices.

  4. Cold bupivacaine versus magnesium sulfate added to room temperature bupivacaine in sonar-guided femoral and sciatic nerve block in arthroscopic anterior cruciate ligament reconstruction surgery

    PubMed Central

    Alzeftawy, Ashraf Elsayed; El-Daba, Ahmad Ali

    2016-01-01

    Background: Cooling of local anesthetic potentiates its action and increases its duration. Magnesium sulfate (MgSo4) added to local anesthetic prolongs the duration of anesthesia and postoperative analgesia with minimal side effects. Aim: The aim of this prospective, randomized, double-blind study was to compare the effect of cold to 4°C bupivacaine 0.5% and Mg added to normal temperature (20–25°C) bupivacaine 0.5% during sonar-guided combined femoral and sciatic nerve blocks on the onset of sensory and motor block, intraoperative anesthesia, duration of sensory and motor block, and postoperative analgesia in arthroscopic anterior cruciate ligament (ACL) reconstruction surgery. Patients and Methods: A total of 90 American Society of Anesthesiologists classes I and II patients who were scheduled to undergo elective ACL reconstruction were enrolled in the study. The patients were randomly allocated to 3 equal groups to receive sonar-guided femoral and sciatic nerve blocks. In Group I, 17 ml of room temperature (20–25°C) 0.5% bupivacaine and 3 ml of room temperature saline were injected for each nerve block whereas in Group II, 17 ml of cold (4°C) 0.5% bupivacaine and 3 ml of cold saline were injected for each nerve block. In Group III, 17 ml of room temperature 0.5% bupivacaine and 3 ml of MgSo4 5% were injected for each nerve block. The onset of sensory and motor block was evaluated every 3 min for 30 min. Surgery was started after complete sensory and motor block were achieved. Intraoperatively, the patients were evaluated for heart rate and mean arterial pressure, rescue analgesic and sedative requirements plus patient and surgeon satisfaction. Postoperatively, hemodynamics, duration of analgesia, resolution of motor block, time to first analgesic, total analgesic consumption, and the incidence of side effects were recorded. Results: There was no statistically significant difference in demographic data, mean arterial pressure, heart rate, and duration of

  5. Development of a guided bone regeneration device using salicylic acid-poly(anhydride-ester) polymers and osteoconductive scaffolds.

    PubMed

    Mitchell, Ashley; Kim, Brian; Cottrell, Jessica; Snyder, Sabrina; Witek, Lukasz; Ricci, John; Uhrich, Kathryn E; O'Connor, J Patrick

    2014-03-01

    Successful repair of craniofacial and periodontal tissue defects ideally involves a combined therapy that includes inflammation modulation, control of soft tissue infiltration, and bone regeneration. In this study, an anti-inflammatory polymer, salicylic acid-based poly(anhydride-ester) (SAPAE) and a three-dimensional osteoconductive ceramic scaffold were evaluated as a combined guided bone regeneration (GBR) system for concurrent control of inflammation, soft tissue ingrowth, and bone repair in a rabbit cranial defect model. At time periods of 1, 3, and 8 weeks, five groups were compared: (1) scaffolds with a solid ceramic cap (as a GBR structure); (2) scaffolds with no cap; (3) scaffolds with a poly(lactide-glycolide) cap; (4) scaffolds with a slow release SAPAE polymer cap; and (5) scaffolds with a fast release SAPAE polymer cap. Cellular infiltration and bone formation in these scaffolds were evaluated to assess inflammation and bone repair capacity of the test groups. The SAPAE polymers suppressed inflammation and displayed no deleterious effect on bone formation. Additional work is warranted to optimize the anti-inflammatory action of the SAPAE, GBR suppression of soft tissue infiltration, and stimulation of bone formation in the scaffolds and create a composite device for successful repair of craniofacial and periodontal tissue defects.

  6. Polymers All Around You!

    ERIC Educational Resources Information Center

    Gertz, Susan

    Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers…

  7. Polymers.

    ERIC Educational Resources Information Center

    Tucker, David C.

    1986-01-01

    Presents an open-ended experiment which has students exploring polymer chemistry and reverse osmosis. This activity involves construction of a polymer membrane, use of it in a simple osmosis experiment, and application of its principles in solving a science-technology-society problem. (ML)

  8. Engineering a multimodal nerve conduit for repair of injured peripheral nerve

    NASA Astrophysics Data System (ADS)

    Quigley, A. F.; Bulluss, K. J.; Kyratzis, I. L. B.; Gilmore, K.; Mysore, T.; Schirmer, K. S. U.; Kennedy, E. L.; O'Shea, M.; Truong, Y. B.; Edwards, S. L.; Peeters, G.; Herwig, P.; Razal, J. M.; Campbell, T. E.; Lowes, K. N.; Higgins, M. J.; Moulton, S. E.; Murphy, M. A.; Cook, M. J.; Clark, G. M.; Wallace, G. G.; Kapsa, R. M. I.

    2013-02-01

    Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate

  9. Surface microstructures on planar substrates and textile fibers guide neurite outgrowth: a scaffold solution to push limits of critical nerve defect regeneration?

    PubMed

    Weigel, Stefan; Osterwalder, Thomas; Tobler, Ursina; Yao, Li; Wiesli, Manuel; Lehnert, Thomas; Pandit, Abhay; Bruinink, Arie

    2012-01-01

    The treatment of critical size peripheral nerve defects represents one of the most serious problems in neurosurgery. If the gap size exceeds a certain limit, healing can't be achieved. Connection mismatching may further reduce the clinical success. The present study investigates how far specific surface structures support neurite outgrowth and by that may represent one possibility to push distance limits that can be bridged. For this purpose, growth cone displacement of fluorescent embryonic chicken spinal cord neurons was monitored using time-lapse video. In a first series of experiments, parallel patterns of polyimide ridges of different geometry were created on planar silicon oxide surfaces. These channel-like structures were evaluated with and without amorphous hydrogenated carbon (a-C:H) coating. In a next step, structured and unstructured textile fibers were investigated. All planar surface materials (polyimide, silicon oxide and a-C:H) proved to be biocompatible, i.e. had no adverse effect on nerve cultures and supported neurite outgrowth. Mean growth cone migration velocity measured on 5 minute base was marginally affected by surface structuring. However, surface structure variability, i.e. ridge height, width and inter-ridge spacing, significantly enhanced the resulting net velocity by guiding the growth cone movement. Ridge height and inter-ridge distance affected the frequency of neurites crossing over ridges. Of the evaluated dimensions ridge height, width, and inter-ridge distance of respectively 3, 10, and 10 µm maximally supported net axon growth. Comparable artificial grooves, fabricated onto the surface of PET fibers by using an excimer laser, showed similar positive effects. Our data may help to further optimize surface characteristics of artificial nerve conduits and bioelectronic interfaces.

  10. Landmark-based versus ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of chronic postherniorrhaphy groin pain: a retrospective study

    PubMed Central

    Trainor, Drew; Moeschler, Susan; Pingree, Matthew; Hoelzer, Brian; Wang, Zhen; Mauck, William; Qu, Wenchun

    2015-01-01

    Background Chronic postherniorrhaphy groin pain (CPGP) is a debilitating condition, which is often refractory to conservative medical management. To our knowledge, there have been no studies directly comparing landmarked-based and ultrasound-guided approaches in this population. Objective To compare the effectiveness of landmark-based and ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of CPGP. Study design This is a retrospective chart review of patients who presented to our tertiary care pain medicine clinic with a diagnosis of CPGP. Inclusion criteria were the following: age >18 years, diagnosis of groin pain, and prior history of herniorrhaphy. Exclusion criteria included those who were seen for initial consultation but were lost to follow-up. Primary outcomes were 50% or greater reduction in pain on visual analog scale (VAS). Secondary outcomes were 30% or greater reduction in VAS pain score, changes in VAS pain scores, and reported complications. Results A total of 36 patients were included in the study. Of them, 20 patients underwent the landmark-based and 16 underwent the ultrasound-guided techniques. There was no significant difference in baseline demographics. The average VAS score preinjection was 7.08 in the landmark-based and 7.0 in the ultrasound-guided groups (P=0.65). A total of 14 patients (70%) in the landmark-based and eleven patients (79%) in the ultrasound-guided groups experienced at least a 50% reduction in VAS scores. There was no statistically significant difference between the two groups (P=1.0), and no complications were noted. We also did not find a significant difference in terms of number of patients with 30% or greater reduction (P=0.71) and changes in VAS pain scores (P=0.64). No complications were reported in either group. Conclusion In our study, there was no statistically significant difference between the landmark-based and ultrasound-guided groups in terms of a reduction in VAS pain scores, and no

  11. In vitro evaluation of gelatin and chitosan electrospun fibers as artificial guide in peripheral nerve repair: a comparative study.

    PubMed

    Gnavi, S; Fornasari, B E; Tonda-Turo, C; Laurano, R; Zanetti, M; Ciardelli, G; Geuna, S

    2016-11-12

    Random and aligned gelatin and chitosan nano-fibers have been prepared by electrospinning tuning the collector rotation speed. The effect of fiber alignment on cell adhesion and proliferation was assessed in vitro by using different Schwann cell and neuronal models. Moreover, actin cytoskeleton organization, lamellipodia and filipodia formation and axon outgrowth were evaluated. Gelatin and chitosan fibers induced similar adhesion and proliferation rate. Gelatin and chitosan random fibers promoted higher adhesion and proliferation rate induction in comparisons to the aligned ones. Although, gelatin and chitosan fibers alignment resulted in SC and axon oriented growth. Filipodia formation was higher on aligned fibers, suggesting that these substrates can promote higher cell migration in comparison to random ones. 50B11 (neuronal cell line) differentiation was higher on gelatin fibers, whereas no differences were observed in DRG explants model. These data suggest that both gelatin and chitosan fibers can be promising substrates to be used in peripheral nerve reconstruction.

  12. Lower cranial nerves.

    PubMed

    Soldatos, Theodoros; Batra, Kiran; Blitz, Ari M; Chhabra, Avneesh

    2014-02-01

    Imaging evaluation of cranial neuropathies requires thorough knowledge of the anatomic, physiologic, and pathologic features of the cranial nerves, as well as detailed clinical information, which is necessary for tailoring the examinations, locating the abnormalities, and interpreting the imaging findings. This article provides clinical, anatomic, and radiological information on lower (7th to 12th) cranial nerves, along with high-resolution magnetic resonance images as a guide for optimal imaging technique, so as to improve the diagnosis of cranial neuropathy.

  13. Transplant of polymer-encapsulated cells genetically engineered to release nerve growth factor allows a normal functional development of the visual cortex in dark-reared rats.

    PubMed

    Pizzorusso, T; Porciatti, V; Tseng, J L; Aebischer, P; Maffei, L

    1997-09-01

    Visual experience is necessary for the normal development of the visual system. Dark-reared mammals show abnormal vision when reintroduced into a normal environment. The absence of visual experience during the critical period results in reduced and/or inappropriate neural responses in visual cortical neurons. The change in electrical activity induced by dark rearing is probably reflected by the modulation of specific unknown molecules. Neurotrophins are present in the developing visual cortex and their production depends on visually driven electrical activity. Recent findings support the possibility that an important link between electrical activity in the visual pathway and correct development of visual properties is represented by neurotrophins. We advance the hypothesis that the visual abnormalities present in dark-reared animals could be due to a decreased production of a neurotrophin secondary to the lack of visual stimulation. We report that some properties of visual cortical response such as receptive field size, orientation selectivity, adaptation to repeated stimulation, response latency and visual acuity are virtually normal in dark-reared rats transplanted with polymer-encapsulated baby hamster kidney cells genetically engineered to release nerve growth factor.

  14. Polymer-based lanthanide luminescent sensor for detection of the hydrolysis product of the nerve agent Soman in water.

    PubMed

    Jenkins, A L; Uy, O M; Murray, G M

    1999-01-15

    The techniques of molecular imprinting and sensitized lanthanide luminescence have been combined to create the basis for a sensor that can selectively measure the hydrolysis product of the nerve agent Soman in water. The sensor functions by selectively and reversibly binding the phosphonate hydrolysis product of this agent to a functionality-imprinted copolymer possessing a coordinatively bound luminescent lanthanide ion, Eu3+. Instrumental support for this device is designed to monitor the appearance of a narrow luminescence band in the 610-nm region of the Eu3+ spectrum that results when the analyte is coordinated to the copolymer. The ligand field shifted luminescence was excited using 1 mW of the 465.8-nm line of an argon ion laser and monitored via an optical fiber using a miniature spectrometer. For this configuration, the limit of detection for the hydrolysis product is 7 parts per trillion (ppt) in solution with a linear range from 10 ppt to 10 ppm. Chemical and spectroscopic selectivities have been combined to reduce the likelihood of false positive analyses. Chemically analogous organophosphorus pesticides tested against the sensor have been shown to not interfere with determination.

  15. Axonal regeneration and remyelination evaluation of chitosan/gelatin-based nerve guide combined with transforming growth factor-β1 and Schwann cells.

    PubMed

    Nie, Xin; Deng, Manjing; Yang, Maojin; Liu, Luchuan; Zhang, Yongjie; Wen, Xiujie

    2014-01-01

    Despite efforts in peripheral nerve injury and regeneration, it is difficult to achieve a functional recovery following extended peripheral nerve lesions. Even if artificial nerve conduit, cell components and growth factors can enhance nerve regeneration, integration in peripheral nerve repair and regeneration remains yet to be explored. For this study, we used chitosan/gelatin nerve graft constructed with collagenous matrices as a vehicle for Schwann cells and transforming growth factor-β1 to bridge a 10-mm gap of the sciatic nerve and explored the feasibility of improving regeneration and reinnervation in rats. The nerve regeneration was assessed with functional recovery, electrophysiological test, retrograde labeling, and immunohistochemistry analysis during the post-operative period of 16 weeks. The results showed that the internal sides of the conduits were compact enough to prevent the connective tissues from ingrowth. Nerve conduction velocity, average regenerated myelin area, and myelinated axon count were similar to those treated with autograft (p > 0.05) but significantly higher than those bridged with chitosan/gelatin nerve graft alone (p < 0.05). Evidences from retrograde labeling and immunohistochemistry analysis are further provided in support of improving axonal regeneration and remyelination. A designed graft incorporating all of the tissue-engineering strategies for peripheral nerve regeneration may provide great progress in tissue engineering for nerve repair.

  16. Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU): Pilot Study in a Swine Model

    PubMed Central

    Huisman, Merel; Staruch, Robert M.; Ladouceur-Wodzak, Michelle; van den Bosch, Maurice A.; Burns, Dennis K.; Chhabra, Avneesh; Chopra, Rajiv

    2015-01-01

    Purpose Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR)-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU) has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system. Methods Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160–300 W). Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson’s trichrome and toluidine blue staining. Results All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation. Conclusion Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may

  17. The optimal timing of post-prostate biopsy magnetic resonance imaging to guide nerve-sparing surgery

    PubMed Central

    Ko, Young Hwii; Song, Phil Hyun; Moon, Ki Hak; Jung, Hee Chang; Cheon, Jun; Sung, Deuk Jae

    2014-01-01

    The goal of our study was to evaluate the impact of the interval between prostate biopsy and magnetic resonance imaging (MRI) on the accuracy of simple tumor localization, which is essential information that enables nerve-sparing surgery. We also sought to determine the optimal timing of a post-biopsy MRI. A total of 184 patients who had undergone MRI before radical prostatectomy at an institution without a predetermined schedule for MRI after a prostate biopsy were enrolled. The mean interval from the biopsy to the MRI was 30.8 ± 18.6 days. The accuracy of the MRI for simplified tumor location (right, left, bilateral and none) was 44.6%. In the group with discordant pathologic and MRI findings, the most common reason recorded was ‘MRI predicted a unilateral lesion, but pathology revealed bilateral lesions’ (58.3%), followed by ‘MRI predicted no lesion, but pathology revealed the presence of a lesion’ (32.0%). Multivariable analysis showed that the discordant group had a shorter interval (25.0 ± 14.3 vs 38.1 ± 20.6 days, P < 0.01) preceding the MRI and a higher rate of hemorrhage as observed by MRI (80.4% vs 54.8%, P < 0.01) in comparison with the accordant group. In receiver operating characteristics analysis, the area under the curve of the MRI interval in accurate prediction of the tumor location was 0.707 (P < 0.001). At the MRI interval's cutoff of 28.5 days, the sensitivity was 73.2% and the specificity was 63.7%. When the MRI was performed within 28 days, the accumulated accuracy was only 26.1% (23/88); however, when it was performed after 28 days, the reversely accumulated accuracy was 61.5% (59/96). These data support a waiting period of at least 4 weeks after a biopsy before performing an MRI for the purposes of surgical refinement. PMID:24407179

  18. A nerve guidance conduit with topographical and biochemical cues: potential application using human neural stem cells.

    PubMed

    Jenkins, Phillip M; Laughter, Melissa R; Lee, David J; Lee, Young M; Freed, Curt R; Park, Daewon

    2015-12-01

    Despite major advances in the pathophysiological understanding of peripheral nerve damage, the treatment of nerve injuries still remains an unmet medical need. Nerve guidance conduits present a promising treatment option by providing a growth-permissive environment that 1) promotes neuronal cell survival and axon growth and 2) directs axonal extension. To this end, we designed an electrospun nerve guidance conduit using a blend of polyurea and poly-caprolactone with both biochemical and topographical cues. Biochemical cues were integrated into the conduit by functionalizing the polyurea with RGD to improve cell attachment. Topographical cues that resemble natural nerve tissue were incorporated by introducing intraluminal microchannels aligned with nanofibers. We determined that electrospinning the polymer solution across a two electrode system with dissolvable sucrose fibers produced a polymer conduit with the appropriate biomimetic properties. Human neural stem cells were cultured on the conduit to evaluate its ability to promote neuronal growth and axonal extension. The nerve guidance conduit was shown to enhance cell survival, migration, and guide neurite extension.

  19. A nerve guidance conduit with topographical and biochemical cues: potential application using human neural stem cells

    NASA Astrophysics Data System (ADS)

    Jenkins, Phillip M.; Laughter, Melissa R.; Lee, David J.; Lee, Young M.; Freed, Curt R.; Park, Daewon

    2015-06-01

    Despite major advances in the pathophysiological understanding of peripheral nerve damage, the treatment of nerve injuries still remains an unmet medical need. Nerve guidance conduits present a promising treatment option by providing a growth-permissive environment that 1) promotes neuronal cell survival and axon growth and 2) directs axonal extension. To this end, we designed an electrospun nerve guidance conduit using a blend of polyurea and poly-caprolactone with both biochemical and topographical cues. Biochemical cues were integrated into the conduit by functionalizing the polyurea with RGD to improve cell attachment. Topographical cues that resemble natural nerve tissue were incorporated by introducing intraluminal microchannels aligned with nanofibers. We determined that electrospinning the polymer solution across a two electrode system with dissolvable sucrose fibers produced a polymer conduit with the appropriate biomimetic properties. Human neural stem cells were cultured on the conduit to evaluate its ability to promote neuronal growth and axonal extension. The nerve guidance conduit was shown to enhance cell survival, migration, and guide neurite extension.

  20. Direct Administration of Nerve-Specific Contrast to Improve Nerve Sparing Radical Prostatectomy

    PubMed Central

    Barth, Connor W.; Gibbs, Summer L.

    2017-01-01

    Nerve damage remains a major morbidity following nerve sparing radical prostatectomy, significantly affecting quality of life post-surgery. Nerve-specific fluorescence guided surgery offers a potential solution by enhancing nerve visualization intraoperatively. However, the prostate is highly innervated and only the cavernous nerve structures require preservation to maintain continence and potency. Systemic administration of a nerve-specific fluorophore would lower nerve signal to background ratio (SBR) in vital nerve structures, making them difficult to distinguish from all nervous tissue in the pelvic region. A direct administration methodology to enable selective nerve highlighting for enhanced nerve SBR in a specific nerve structure has been developed herein. The direct administration methodology demonstrated equivalent nerve-specific contrast to systemic administration at optimal exposure times. However, the direct administration methodology provided a brighter fluorescent nerve signal, facilitating nerve-specific fluorescence imaging at video rate, which was not possible following systemic administration. Additionally, the direct administration methodology required a significantly lower fluorophore dose than systemic administration, that when scaled to a human dose falls within the microdosing range. Furthermore, a dual fluorophore tissue staining method was developed that alleviates fluorescence background signal from adipose tissue accumulation using a spectrally distinct adipose tissue specific fluorophore. These results validate the use of the direct administration methodology for specific nerve visualization with fluorescence image-guided surgery, which would improve vital nerve structure identification and visualization during nerve sparing radical prostatectomy. PMID:28255352

  1. Direct Administration of Nerve-Specific Contrast to Improve Nerve Sparing Radical Prostatectomy.

    PubMed

    Barth, Connor W; Gibbs, Summer L

    2017-01-01

    Nerve damage remains a major morbidity following nerve sparing radical prostatectomy, significantly affecting quality of life post-surgery. Nerve-specific fluorescence guided surgery offers a potential solution by enhancing nerve visualization intraoperatively. However, the prostate is highly innervated and only the cavernous nerve structures require preservation to maintain continence and potency. Systemic administration of a nerve-specific fluorophore would lower nerve signal to background ratio (SBR) in vital nerve structures, making them difficult to distinguish from all nervous tissue in the pelvic region. A direct administration methodology to enable selective nerve highlighting for enhanced nerve SBR in a specific nerve structure has been developed herein. The direct administration methodology demonstrated equivalent nerve-specific contrast to systemic administration at optimal exposure times. However, the direct administration methodology provided a brighter fluorescent nerve signal, facilitating nerve-specific fluorescence imaging at video rate, which was not possible following systemic administration. Additionally, the direct administration methodology required a significantly lower fluorophore dose than systemic administration, that when scaled to a human dose falls within the microdosing range. Furthermore, a dual fluorophore tissue staining method was developed that alleviates fluorescence background signal from adipose tissue accumulation using a spectrally distinct adipose tissue specific fluorophore. These results validate the use of the direct administration methodology for specific nerve visualization with fluorescence image-guided surgery, which would improve vital nerve structure identification and visualization during nerve sparing radical prostatectomy.

  2. Nerve biopsy

    MedlinePlus

    ... Loss of axon tissue Metabolic neuropathies Necrotizing vasculitis Sarcoidosis Risks Allergic reaction to the local anesthetic Discomfort ... Neurosarcoidosis Peripheral neuropathy Primary amyloidosis Radial nerve dysfunction Sarcoidosis Tibial nerve dysfunction Review Date 6/1/2015 ...

  3. Clinical Neuropathology practice guide 3-2014: Combined nerve and muscle biopsy in the diagnostic work-up of neuropathy – the Bordeaux experience

    PubMed Central

    Vital, Anne; Vital, Claude

    2014-01-01

    Simultaneous combined superficial peroneal nerve and peroneous brevis muscle biopsy, via the same cutaneous incision, allows examination of several tissue specimens and significantly improves the diagnosis of systemic diseases with peripheral nerve involvement. Vasculitides are certainly the most frequently diagnosed on neuro-muscular biopsies, but this procedure is also well advised to asses a diagnosis of sarcoidosis or amyloidosis. More occasionally, combined nerve and muscle biopsy may reveal an unpredicted diagnosis of cholesterol embolism, intra-vascular lymphoma, or enables complementary diagnosis investigations on mitochondrial cytopathy or storage disease. PMID:24618073

  4. Common peroneal nerve dysfunction

    MedlinePlus

    Neuropathy - common peroneal nerve; Peroneal nerve injury; Peroneal nerve palsy ... type of peripheral neuropathy (damage to nerves outside the brain ... nerve injuries. Damage to the nerve disrupts the myelin sheath ...

  5. Peripheral nerve conduits: technology update

    PubMed Central

    Arslantunali, D; Dursun, T; Yucel, D; Hasirci, N; Hasirci, V

    2014-01-01

    Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS) and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers) and designs (tubular, fibrous, and matrix type) are being presented. PMID:25489251

  6. Comparison of Nerve Stimulation-guided Axillary Brachial Plexus Block, Single Injection versus Four Injections: A Prospective Randomized Double-blind Study

    PubMed Central

    Badiger, Santoshi V.; Desai, Sameer N.

    2017-01-01

    Background: A variety of techniques have been described for the axillary block using nerve stimulator, either with single injection, two, three, or four separate injections. Identification of all the four nerves is more difficult and time-consuming than other methods. Aims: Aim of the present study is to compare success rate, onset, and duration of sensory and motor anesthesia of axillary block using nerve stimulator, either with single injection after identification of any one of the four nerves or four separate injections following identification of each of nerve. Setting and Design: Prospective, randomized, double-blind study. Patients undergoing forearm and hand surgeries under axillary block. Methodology: One hundred patients, aged 18–75 years, were randomly allocated into two groups of 50 each. Axillary block was performed under the guidance of nerve stimulator with a mixture of 18 ml of 1.5% lignocaine and 18 ml of 0.5% bupivacaine. In the first group (n = 50), all 36 ml of local anesthetic was injected after the identification of motor response to any one of the nerves and in Group 2, all the four nerves were identified by the motor response, and 9 ml of local anesthetic was injected at each of the nerves. The success rate of the block, onset, and duration of sensory and motor block was assessed. Statistical Analysis: Categorical variables were compared using the Chi-square test, and continuous variables were compared using independent t-test. Results: The success rate of the block with four injection technique was higher compared to single-injection technique (84% vs. 56%, P = 0.02). Four injection groups had a faster onset of sensory and motor block and prolonged duration of analgesia compared to single-injection group (P < 0.001). There were no significant differences in the incidence of accidental arterial puncture and hemodynamic parameter between the groups. Conclusion: Identification of all the four nerves produced higher success rate and better

  7. Real-time ultrasound-guided comparison of adductor canal block and psoas compartment block combined with sciatic nerve block in laparoscopic knee surgeries

    PubMed Central

    Messeha, Medhat M.

    2016-01-01

    Background: Lumbar plexus block, combined with a sciatic nerve block, is an effective locoregional anesthetic technique for analgesia and anesthesia of the lower extremity. The aim of this study was to compare the clinical results outcome of the adductor canal block versus the psoas compartment block combined with sciatic nerve block using real time ultrasound guidance in patients undergoing elective laparoscopic knee surgeries. Patients and Methods: Ninety patients who were undergoing elective laparoscopic knee surgeries were randomly allocated to receive a sciatic nerve block in addition to lumbar plexus block using either an adductor canal block (ACB) or a posterior psoas compartment approach (PCB) using 25 ml of bupivacine 0.5% with adrenaline 1:400,000 injection over 2-3 minutes while observing the distribution of the local anesthetic in real time. Successful nerve block was defined as a complete loss of pinprick sensation in the region that is supplied by the three nerves along with adequate motor block, 30 minutes after injection. The degree of motor block was evaluated 30 minutes after the block procedure. The results of the present study showed that the real time ultrasound guidance of PCB is more effective than ACB approach. Although the sensory blockade of the femoral nerve achieved equally by both techniques, the LFC and OBT nerves were faster and more effectively blocked with PCB technique. Also PCB group showed significant complete sensory block without need for general anesthesia, significant decrease in the post-operative VAS and significant increase time of first analgesic requirement as compared to the ACB group. Result and Conclusion: The present study demonstrates that blockade of lumber plexus by psoas compartment block is more effective in complete sensory block without general anesthesia supplementation in addition to decrease post-operative analgesic requirement than adductor canal block. PMID:27212766

  8. Electrospray synthesis of monodisperse polymer particles in a broad (60 nm-2 μm) diameter range: guiding principles and formulation recipes.

    PubMed

    Almería, Begoña; Gomez, Alessandro

    2014-03-01

    This study reports on a methodology to control the size of polymer particles generated by the electrospray (ES) drying route, with emphasis on the generation of biodegradable polymer nanoparticles that are well suited for biomedical applications. The ability to produce spherical poly(lactic-co-glycolic) acid (PLGA) particles with and without encapsulated active agent, with relative standard deviation not exceeding 15%, was demonstrated over a remarkably broad (60 nm-2 μm) diameter range. By judiciously choosing ES parameters and solution properties, we can control the monodispersity and the size of the obtained particles, tailoring it to a specific application. The main parameters affecting particle size include solution electrical conductivity, flow rate and initial polymer volume fraction. Quasi-monodispersity at both the micro- and the more challenging nano-scale was achieved by avoiding Coulomb fission in the spray droplets, via entanglement of the polymer chains within the droplets rather than by charge neutralization. Guiding principles in the formulation of the solutions to satisfy a multiplicity of constraints are provided along with an extensive database of "recipes".

  9. Fabrication of seamless electrospun collagen/PLGA conduits whose walls comprise highly longitudinal aligned nanofibers for nerve regeneration.

    PubMed

    Ouyang, Yuanming; Huang, Chen; Zhu, Yi; Fan, Cunyi; Ke, Qinfei

    2013-06-01

    An ideal nerve scaffold should supply structural guidance and trophic support to facilitate nerve regeneration. Aligned electrospun nanofibers have shown considerable promise for the precise guidance of regenerating axons in vitro and in vivo. Therefore, uniaxially aligned three-dimension (3D) nanofiberous scaffolds may allow regenerating axons to traverse large gaps to treat severe nerve injuries. However, the aligned 3D conduit was always rolled by an aligned 2-dimensional (2D) sheet in current fabrication methods, which was inconvenient for transplant due to the discontinuous joint and inconsistent size. We developed a modified one-step electrospinning technique to produce a seamless 3D nanofiberous nerve conduit (NC) with highly longitudinal aligned nanofibers that combines the biocompatibility of natural collagen and the strength of the synthetic polymer poly(lactic-co-glycolic acid) (PLGA). Scanning electron microscopy (SEM) confirmed the parallel alignment of the scaffold fibers. To test the effectiveness of these scaffolds at restoring neuronal connections, they were implanted into adult rats across a 13 mm sciatic nerve defect. Tests of, motor function, nerve conduction, axonal and Schwann cell morphology, and marker expression all revealed that uniaxially aligned seamless 3D electrospun collagen/PLGA NCs were superior to randomly oriented NCs and inferior to autografts for promoting axon regeneration, myelination, action potential propagation, neuromuscular transmission, and functional recovery. These uniaxially aligned seamless 3D electrospun collagen/PLGA nerve guides can also incorporate signaling molecules and additional structural cues to guide nerve growth, and so may be a promising substitute for autogenous nerve grafts.

  10. Minimally Invasive Magnetic Resonance Imaging-Guided Free-Hand Aspiration of Symptomatic Nerve Route Compressing Lumbosacral Cysts Using a 1.0-Tesla Open Magnetic Resonance Imaging System

    SciTech Connect

    Bucourt, Maximilian de Streitparth, Florian Collettini, Federico; Guettler, Felix; Rathke, Hendrik; Lorenz, Britta; Rump, Jens; Hamm, Bernd; Teichgraeber, U. K.

    2012-02-15

    Purpose: To evaluate the feasibility of minimally invasive magnetic resonance imaging (MRI)-guided free-hand aspiration of symptomatic nerve route compressing lumbosacral cysts in a 1.0-Tesla (T) open MRI system using a tailored interactive sequence. Materials and Methods: Eleven patients with MRI-evident symptomatic cysts in the lumbosacral region and possible nerve route compressing character were referred to a 1.0-T open MRI system. For MRI interventional cyst aspiration, an interactive sequence was used, allowing for near real-time position validation of the needle in any desired three-dimensional plane. Results: Seven of 11 cysts in the lumbosacral region were successfully aspirated (average 10.1 mm [SD {+-} 1.9]). After successful cyst aspiration, each patient reported speedy relief of initial symptoms. Average cyst size was 9.6 mm ({+-}2.6 mm). Four cysts (8.8 {+-} 3.8 mm) could not be aspirated. Conclusion: Open MRI systems with tailored interactive sequences have great potential for cyst aspiration in the lumbosacral region. The authors perceive major advantages of the MR-guided cyst aspiration in its minimally invasive character compared to direct and open surgical options along with consecutive less trauma, less stress, and also less side-effects for the patient.

  11. Chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor promotes sciatic nerve repair

    PubMed Central

    Zhang, Yanru; Zhang, Hui; Katiella, Kaka; Huang, Wenhua

    2014-01-01

    A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune rejection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regeneration. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group > chemically extracted acellular nerve graft + ciliary neurotrophic factor group > chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anastomosis, but superior to chemically extracted acellular allogeneic nerve bridging alone. PMID:25221592

  12. Use of GDNF-Releasing Nanofiber Nerve Guide Conduits for the Repair of Conus Medullaris/Cauda Equina Injury in the Nonhuman Primate

    DTIC Science & Technology

    2012-10-01

    nanofibers are deposited onto the gelatin films via electrospinning so that the fibers are aligned upon the short axis. The films are crosslinked with...covered with a random mesh of PCL nanofibers via electrospinning to generate suitably thick but porous conduit walls to protect the regenerating nerve

  13. Three-layer microfibrous peripheral nerve guide conduit composed of elastin-laminin mimetic artificial protein and poly(L-lactic acid)

    NASA Astrophysics Data System (ADS)

    Kakinoki, Sachiro; Nakayama, Midori; Moritan, Toshiyuki; Yamaoka, Tetsuji

    2014-07-01

    We developed a microfibrous poly(L-lactic acid) (PLLA) nerve conduit with a three-layered structure to simultaneously enhance nerve regeneration and prevent adhesion of surrounding tissue. The inner layer was composed of PLLA microfiber containing 25% elastin-laminin mimetic protein (AG73-(VPGIG)30) that promotes neurite outgrowth. The thickest middle layer was constructed of pure PLLA microfibers that impart the large mechanical stremgth to the conduit. A 10% poly(ethylene glycol) was added to the outer layer to prevent the adhesion with the surrounding tissue. The AG73-(VPGIG)30 composisting of an elastin-like repetitive sequence (VPGIG)30 and a laminin-derived sequence (RKRLQVQLSIRT: AG73) was biosynthesized using Escherichia coli. The PLLA microfibrous conduits were fabricated using an electrospinning procedure. AG73-(VPGIG)30 was successfully mixed in the PLLA microfibers, and the PLLA/AG73-(VPGIG)30 microfibers were stable under physiological conditions. The PLLA/AG73-(VPGIG)30 microfibers enhanced adhesion and neurite outgrowth of PC12 cells. The electrospun microfibrous conduit with a three-layered structure was implanted for bridging a 2.0-cm gap in the tibial nerve of a rabbit. Two months after implantation, no adhesion of surrounding tissue was observed, and the action potential was slightly improved in the nerve conduit with the PLLA/AG73-(VPGIG)30 inner layer.

  14. Prevention and Management of Nerve Injuries in Thoracic Surgery.

    PubMed

    Auchincloss, Hugh G; Donahue, Dean M

    2015-11-01

    Nerve injuries can cause substantial morbidity after thoracic surgical procedures. These injuries are preventable, provided that the surgeon has a thorough understanding of the anatomy and follows important surgical principles. When nerve injuries occur, it is important to recognize the options available in the immediate and postoperative settings, including expectant management, immediate nerve reconstruction, or auxiliary procedures. This article covers the basic anatomy and physiology of nerves and nerve injuries, an overview of techniques in nerve reconstruction, and a guide to the nerves most commonly involved in thoracic operative procedures.

  15. Photoluminescent and biodegradable polycitrate-polyethylene glycol-polyethyleneimine polymers as highly biocompatible and efficient vectors for bioimaging-guided siRNA and miRNA delivery.

    PubMed

    Wang, Min; Guo, Yi; Yu, Meng; Ma, Peter X; Mao, Cong; Lei, Bo

    2017-02-20

    Development of biodegradable and biocompatible non-viral vectors with intrinsical multifunctional properties such as bioimaging ability for highly efficient nucleic acids delivery still remains a challenge. Here, a biodegradable poly (1,8-octanedio-citric acid)-co-polyethylene glycol grafted with polyethyleneimine (PEI) (POCG-PEI) polymers with the photoluminescent capacity were synthesized for nucleic acids delivery (siRNA and miRNA). POCG-PEI polymers can efficiently bind various nucleic acids, protect them against enzymatic degradation and release the genes in the presence of polyanionic heparin. POCG-PEI also showed a significantly low cytotoxicity, enhanced cellular uptake and high transfection efficiency of nucleic acids, as compared to commercial transfection agents, lipofectamine 2000 (Lipo) and polyethylenimine (PEI 25K). POCG-PEI polymers demonstrate an excellent photostability, which allows for imaging the cells and real-time tracking the nucleic acids delivery. The photoluminescent property, low cytotoxicity, biodegradation, good gene binding and protection ability and high genes delivery efficiency make POCG-PEI highly competitive as a non-virus vector for genes delivery and real-time bioimaging applications. Our results may be also an important step for designing biodegradable biomaterials with multifunctional properties towards bioimaging-guided genes therapeutic applications.

  16. Nerve Blocks

    MedlinePlus

    ... Sometimes the needle has to be inserted fairly deep to reach the nerve causing your problem. This ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  17. Fluoroscopic-guided radiofrequency ablation of the basivertebral nerve: application and analysis with multiple imaging modalities in an ovine model (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Bergeron, Jeffrey A.; Eskey, Cliff J.; Attawia, Mohammed; Patel, Samit J.; Ryan, Thomas P.; Pellegrino, Richard; Sutton, Jeffrey; Crombie, John; Paul, B. T.; Hoopes, P. J.

    2005-04-01

    Pathologic involvement of the basivertebral nerve, an intraosseous vertebral nerve found in humans and most mammalian species, may play a role in some forms of back pain. This study was designed to assess the feasibility and effects of the percutaneous delivery of radiofrequency (RF) energy to thermally ablate the basivertebral nerve in the lumbar vertebrae of mature sheep. Using fluoroscopic guidance, a RF bipolar device was placed and a thermal dose delivered to lumbar vertebral bodies in sheep. Post-treatment assessment included multiple magnetic resonance imaging (MRI) techniques and computed tomography (CT). These data were analyzed and correlated to histopathology and morphometry findings to describe the cellular and boney structural changes resulting from the treatment. Imaging modalities MRI and CT can be implemented to non-invasively describe treatment region and volume, marrow cellular effects, and bone density alterations immediately following RF treatment and during convalescence. Such imaging can be utilized to assess treatment effects and refine the thermal dose to vertebral body volume ratio used in treatment planning. This information will be used to improve the therapeutic ratio and develop a treatment protocol for human applications.

  18. [Localization of peripheral nerves. Success and safety with electrical nerve stimulation].

    PubMed

    Neuburger, M; Schwemmer, U; Volk, T; Gogarten, W; Kessler, P; Steinfeldt, T

    2014-05-01

    Peripheral electrical nerve stimulation is one of the standard applications in peripheral regional anesthesia in addition to the ultrasound technique. Among other findings, the visualization of needle and nerve during ultrasound-guided blockade caused a change in clinical practice of peripheral nerve stimulation in the last decade. In the present article old and new aspects of principles and clinical practice of the nerve stimulation technique are presented and summarized in a total clinical concept in order to achieve safe and successful peripheral regional anesthesia using electrical peripheral nerve stimulation.

  19. Development of a smart guide wire using an electrostrictive polymer: option for steerable orientation and force feedback

    PubMed Central

    Ganet, F.; Le, M. Q.; Capsal, J. F.; Lermusiaux, P.; Petit, L.; Millon, A.; Cottinet, P. J.

    2015-01-01

    The development of steerable guide wire or catheter designs has been strongly limited by the lack of enabling actuator technologies. This paper presents the properties of an electrostrive actuator technology for steerable actuation. By carefully tailoring material properties and the actuator design, which can be integrated in devices, this technology should realistically make it possible to obtain a steerable guide wire design with considerable latitude. Electromechanical characteristics are described, and their impact on a steerable design is discussed. PMID:26673883

  20. Development of a smart guide wire using an electrostrictive polymer: option for steerable orientation and force feedback.

    PubMed

    Ganet, F; Le, M Q; Capsal, J F; Lermusiaux, P; Petit, L; Millon, A; Cottinet, P J

    2015-12-17

    The development of steerable guide wire or catheter designs has been strongly limited by the lack of enabling actuator technologies. This paper presents the properties of an electrostrive actuator technology for steerable actuation. By carefully tailoring material properties and the actuator design, which can be integrated in devices, this technology should realistically make it possible to obtain a steerable guide wire design with considerable latitude. Electromechanical characteristics are described, and their impact on a steerable design is discussed.

  1. Optic Nerve Decompression

    MedlinePlus

    ... Nerve Decompression Dacryocystorhinostomy (DCR) Disclosure Statement Printer Friendly Optic Nerve Decompression John Lee, MD Introduction Optic nerve decompression is a surgical procedure aimed at ...

  2. Ulnar nerve dysfunction

    MedlinePlus

    Neuropathy - ulnar nerve; Ulnar nerve palsy; Mononeuropathy; Cubital tunnel syndrome ... compressed in the elbow, a problem called cubital tunnel syndrome may result. When damage destroys the nerve ...

  3. The role of peripheral nerve ECM components in the tissue engineering nerve construction.

    PubMed

    Gao, Xupeng; Wang, Yu; Chen, Jifeng; Peng, Jiang

    2013-01-01

    The extracellular matrix (ECM) is the naturally occurring substrate that provides a support structure and an attachment site for cells. It also produces a biological signal, which plays an important role in and has significant impact on cell adhesion, migration, proliferation, differentiation, and gene expression. Peripheral nerve repair is a complicated process involving Schwann cell proliferation and migration, 'bands of Büngner' formation, and newborn nerve extension. In the ECM of peripheral nerves, macromolecules are deposited among cells; these constitute the microenvironment of Schwann cell growth. Such macromolecules include collagen (I, III, IV, V), laminin, fibronectin, chondroitin sulfate proteoglycans (CSPGs), and other nerve factors. Collagen, the main component of ECM, provides structural support and guides newborn neurofilament extension. Laminin, fibronectin, CSPGs, and neurotrophic factors, are promoters or inhibitors, playing different roles in nerve repair after injury. By a chemical decellularization process, acellular nerve allografting eliminates the antigens responsible for allograft rejection and maintains most of the ECM components, which can effectively guide and enhance nerve regeneration. Thus, the composition and features of peripheral nerve ECM suggest its superiority as nerve repair material. This review focuses on the structure, function, and application in the tissue engineering nerve construction of the peripheral nerve ECM components.

  4. Essential regional nerve blocks for the dermatologist: Part 2.

    PubMed

    Davies, T; Karanovic, S; Shergill, B

    2014-12-01

    Following on from Part 1 of the series (regional nerve blocks for the face and scalp), we guide the clinician through the anatomy and cutaneous innervation of the digits, wrist and ankle, providing a practical step-by-step guide to regional nerve blockade of these areas.

  5. Vagus Nerve Stimulation

    MedlinePlus

    Vagus nerve stimulation Overview By Mayo Clinic Staff Vagus nerve stimulation is a procedure that involves implantation of a device that stimulates the vagus nerve with electrical impulses. There's one vagus nerve on ...

  6. Nerve biopsy (image)

    MedlinePlus

    Nerve biopsy is the removal of a small piece of nerve for examination. Through a small incision, a sample ... is removed and examined under a microscope. Nerve biopsy may be performed to identify nerve degeneration, identify ...

  7. Localized delivery of doxorubicin in vivo from polymer-modified thermosensitive liposomes with MR-guided focused ultrasound-mediated heating

    PubMed Central

    Ta, Terence; Bartolak-Suki, Elizabeth; Park, Eun-Joo; Karrobi, Kavon M.; McDannold, Nathan J.; Porter, Tyrone M.

    2014-01-01

    Thermosensitive liposomes have emerged as a viable strategy for localized delivery and triggered release of chemotherapy. MR-guided focused ultrasound (MRgFUS) has the capability of heating tumors in a controlled manner, and when combined with thermosensitive liposomes can potentially reduce tumor burden in vivo. However, the impact of this drug delivery strategy has rarely been investigated. We have developed a unique liposome formulation modified with p(NIPAAm-co-PAA), a polymer that confers sensitivity to both temperature and pH. These polymer-modified thermosensitive liposomes (PTSL) demonstrated sensitivity to focused ultrasound, and required lower thermal doses and were more cytotoxic than traditional formulations in vitro. A set of acoustic parameters characterizing optimal release from PTSL in vitro was applied in the design of a combined MRgFUS/PTSL delivery platform. This platform more effectively reduced tumor burden in vivo when compared to free drug and traditional formulations. Histological analysis indicated greater tumor penetration, more extensive ECM remodeling, and greater cell destruction in tumors administered PTSL, correlating with improved response to the therapy. PMID:25151982

  8. Fire Safety Aspects of Polymeric Materials. Volume 5. Elements of Polymer Fire Safety and Guide to the Designer

    DTIC Science & Technology

    1979-01-01

    can be prepared by substituting the corresponding acid for hydrochloric acid in the reaction with phosphine and formaldehyde . A fire retardant for...one phenolic fiber, Kynol®, has been developed. In its preparation a phenol- formaldehyde polymer is first spun into multifilament yarns and is then...cured with formaldehyde . The Kynol® fiber is light yellow, but can be bleached to a pure white. The strength of the fiber is low, as is its abrasion

  9. The swimmeret system of crayfish: a practical guide for the dissection of the nerve cord and extracellular recordings of the motor pattern.

    PubMed

    Seichter, Henriette A; Blumenthal, Felix; Smarandache-Wellmann, Carmen R

    2014-11-25

    Here we demonstrate the dissection of the crayfish abdominal nerve cord. The preparation comprises the last two thoracic ganglia (T4, T5) and the chain of abdominal ganglia (A1 to A6). This chain of ganglia includes the part of the central nervous system (CNS) that drives coordinated locomotion of the pleopods (swimmerets): the swimmeret system. It is known for over five decades that in crayfish each swimmeret is driven by its own independent pattern generating kernel that generates rhythmic alternating activity . The motor neurons innervating the musculature of each swimmeret comprise two anatomically and functionally distinct populations. One is responsible for the retraction (power stroke, PS) of the swimmeret. The other drives the protraction (return stroke, RS) of the swimmeret. Motor neurons of the swimmeret system are able to produce spontaneously a fictive motor pattern, which is identical to the pattern recorded in vivo. The aim of this report is to introduce an interesting and convenient model system for studying rhythm generating networks and coordination of independent microcircuits for students' practical laboratory courses. The protocol provided includes step-by-step instructions for the dissection of the crayfish's abdominal nerve cord, pinning of the isolated chain of ganglia, desheathing the ganglia and recording the swimmerets fictive motor pattern extracellularly from the isolated nervous system. Additionally, we can monitor the activity of swimmeret neurons recorded intracellularly from dendrites. Here we also describe briefly these techniques and provide some examples. Furthermore, the morphology of swimmeret neurons can be assessed using various staining techniques. Here we provide examples of intracellular (by iontophoresis) dye filled neurons and backfills of pools of swimmeret motor neurons. In our lab we use this preparation to study basic functions of fictive locomotion, the effect of sensory feedback on the activity of the CNS, and

  10. Long-term stable transmission of 3-keV Ne7+ ions guided through nanocapillaries in polymers

    NASA Astrophysics Data System (ADS)

    Stolterfoht, N.; Herczku, P.; Juhász, Z.; Kovács, S. T. S.; Rácz, R.; Biri, S.; Sulik, B.

    2016-11-01

    We studied blocking effects on 3-keV Ne7+ ion guiding through nanocapillaries in highly insulating polyethylene terephthalate (PET) manufactured at different laboratories. The experiments were motivated in view of previous measurement with PET capillaries prepared at the GSI Helmholtz-Zentrum for which significant blocking effects were observed, whereas in various previous studies with PET capillaries these effects could not be detected. As the blocking effect on the GSI capillaries strongly depends on their areal density, similar dependencies were studied with the FLNR capillaries. Long-term stable transmission was observed for all densities of the FLNR capillaries in contrast to the previous results. These observations are interpreted by differences in the capillary surface conductivities in accordance with charge patch formations within the capillaries. It is pointed out that the observed stable transmission is favorable for applications of ion guiding in capillaries.

  11. Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.

    PubMed

    Jiang, Xu; Mi, Ruifa; Hoke, Ahmet; Chew, Sing Yian

    2014-05-01

    Fibre structures represent a potential class of materials for the formation of synthetic nerve conduits due to their biomimicking architecture. Although the advantages of fibres in enhancing nerve regeneration have been demonstrated, in vivo evaluation of fibre size effect on nerve regeneration remains limited. In this study, we analyzed the effects of fibre diameter of electrospun conduits on peripheral nerve regeneration across a 15-mm critical defect gap in a rat sciatic nerve injury model. By using an electrospinning technique, fibrous conduits comprised of aligned electrospun poly (ε-caprolactone) (PCL) microfibers (981 ± 83 nm, Microfiber) or nanofibers (251 ± 32 nm, Nanofiber) were obtained. At three months post implantation, axons regenerated across the defect gap in all animals that received fibrous conduits. In contrast, complete nerve regeneration was not observed in the control group that received empty, non-porous PCL film conduits (Film). Nanofiber conduits resulted in significantly higher total number of myelinated axons and thicker myelin sheaths compared to Microfiber and Film conduits. Retrograde labeling revealed a significant increase in number of regenerated dorsal root ganglion sensory neurons in the presence of Nanofiber conduits (1.93 ± 0.71 × 10(3) vs. 0.98 ± 0.30 × 10(3) in Microfiber, p < 0.01). In addition, the compound muscle action potential (CMAP) amplitudes were higher and distal motor latency values were lower in the Nanofiber conduit group compared to the Microfiber group. This study demonstrated the impact of fibre size on peripheral nerve regeneration. These results could provide useful insights for future nerve guide designs.

  12. The effect of acetylcholine-like biomimetic polymers on neuronal growth.

    PubMed

    Tu, Qin; Li, Li; Zhang, Yanrong; Wang, Jianchun; Liu, Rui; Li, Manlin; Liu, Wenming; Wang, Xueqin; Ren, Li; Wang, Jinyi

    2011-04-01

    Driven by clinical needs, nerve regeneration studies have recently become the focus of research and area of growth in tissue engineering. Biomimetic polymer synthesis and functional interface construction is a promising solution to induce neuritic sprouting and guide the regenerating nerve. However, few studies have been made on primary hippocampal neurons. In this study, a new type of acetylcholine-like biomimetic polymers for their potential in biomaterial-modulated nerve regeneration application is synthesized using click chemistry and free radical polymerization. The structure of the synthesized polymers includes a "bioactive" unit (acetylcholine-like unit) and a "bioinert" unit [poly(ethylene glycol) unit]. To explore the effects of the bioactive unit and the bioinert unit on neuronal growth, different ratios of the two initial monomers poly(ethylene glycol) monomethyl ether-glycidyl methacrylate (MePEG-GMA) and dimethylaminoethyl methacrylate (DMAEMA) were employed and five different polymers were synthesized. Their chemical structures were characterized using (1)H nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, polydispersity, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. Culturing of the primary rat hippocampal neurons on the polymeric surfaces show that the ratio of the two initial monomers utilized for polymer synthesis significantly affects neuronal growth. Rat hippocampal neurons show different growth morphologies on different polymeric surfaces. The polymeric surface prepared with 1:60 (mol/mol) of MePEG-GMA to DMAEMA induces neuronal regenerative responses similar to that on poly-l-lysine, a very common benchmark material for nerve cell cultures. These results suggest that acetylcholine-like biomimetic polymers are potential biomaterials for neural engineering applications

  13. Ultrasound-guided femoro-sciatic nerve block for post-operative analgesia after below knee orthopaedic surgeries under subarachnoid block: Comparison between clonidine and dexmedetomidine as adjuvants to levobupivacaine

    PubMed Central

    Chaudhary, Sudarshan Kumar; Verma, Ravinder Kumar; Rana, Shelly; Singh, Jai; Gupta, Bhanu; Singh, Yuvraj

    2016-01-01

    Background and Aims: The advent of ultrasonographic-guided techniques has led to increased interest in femoro-sciatic nerve block (FSNB) for lower limb surgeries. α2-agonists have been used recently as adjuvants to local anaesthetics in nerve blocks. We aimed to compare equal doses of clonidine or dexmedetomidine as an adjuvant to levobupivacaine in FSNB for post-operative analgesia. Methods: Ninety patients scheduled to undergo below knee orthopaedic surgeries under subarachnoid block were divided into three groups: Group LL (n = 30) patients received 38 mL of 0.125% levobupivacaine with 2 mL normal saline, Group LD (n = 30) patients received 38 mL of 0.125% levobupivacaine with 0.5 μg/kg dexmedetomidine and Group LC (n = 30) received 38 mL of 0.125% levobupivacaine with 0.5 μg/kg clonidine in saline to make total drug volume of 40 mL. The primary and secondary outcome variables were duration of analgesia and rescue analgesic requirement, verbal rating score respectively. Continuous variables were analysed with analysis of variance or the Kruskal–Wallis test on the basis of data distribution. Categorical variables were analysed with the contingency table analysis and the Fisher's exact test. Results: Duration of analgesia was prolonged with dexmedetomidine (10.17 ± 2.40 h) and clonidine (7.31 ± 1.76 h) as compared to control (4.16 ± 1.04 h, P = 0.00). Significantly lower pain scores were observed in dexmedetomidine group as compared to clonidine up to 8 h post-operatively. Conclusion: Equal doses of clonidine or dexmedetomidine added to levobupivacaine prolonged the duration of analgesia, decreased requirement of rescue analgesia. Dexmedetomidine delays the requirement of rescue analgesics with better pain scores as compared to clonidine. PMID:27512164

  14. Smart polymer brush nanostructures guide the self-assembly of pore-spanning lipid bilayers with integrated membrane proteins

    NASA Astrophysics Data System (ADS)

    Wilhelmina de Groot, G.; Demarche, Sophie; Santonicola, M. Gabriella; Tiefenauer, Louis; Vancso, G. Julius

    2014-01-01

    Nanopores in arrays on silicon chips are functionalized with pH-responsive poly(methacrylic acid) (PMAA) brushes and used as supports for pore-spanning lipid bilayers with integrated membrane proteins. Robust platforms are created by the covalent grafting of polymer brushes using surface-initiated atom transfer radical polymerization (ATRP), resulting in sensor chips that can be successfully reused over several assays. His-tagged proteins are selectively and reversibly bound to the nitrilotriacetic acid (NTA) functionalization of the PMAA brush, and consequently lipid bilayer membranes are formed. The enhanced membrane resistance as determined by electrochemical impedance spectroscopy and free diffusion of dyed lipids observed as fluorescence recovery after photobleaching confirmed the presence of lipid bilayers. Immobilization of the His-tagged membrane proteins on the NTA-modified PMAA brush near the pore edges is characterized by fluorescence microscopy. This system allows us to adjust the protein density in free-standing bilayers, which are stabilized by the polymer brush underneath. The potential application of the integrated platform for ion channel protein assays is demonstrated.

  15. Optic Nerve.

    PubMed

    Gordon, Lynn K

    2016-10-28

    Optic nerve diseases arise from many different etiologies including inflammatory, neoplastic, genetic, infectious, ischemic, and idiopathic. Understanding some of the characteristics of the most common optic neuropathies along with therapeutic approaches to these diseases is helpful in designing recommendations for individual patients. Although many optic neuropathies have no specific treatment, some do, and it is those potentially treatable or preventable conditions which need to be recognized in order to help patients regain their sight or develop a better understanding of their own prognosis. In this chapter several diseases are discussed including idiopathic intracranial hypertension, optic neuritis, ischemic optic neuropathies, hereditary optic neuropathies, trauma, and primary tumors of the optic nerve. For each condition there is a presentation of the signs and symptoms of the disease, in some conditions the evaluation and diagnostic criteria are highlighted, and where possible, current therapy or past trials are discussed.

  16. Mind over Matter. Teacher's Guide.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHHS/PHS), Rockville, MD.

    This teacher's guide aims to develop an understanding among students in grades 5-9 about the biological effects of drug use. The guide provides background information on the anatomy of the brain, nerve cells and neurotransmission, and the effects of drugs on the brain. Drugs described in this guide include marijuana, opiates, inhalants,…

  17. A Romanian therapeutic approach to peripheral nerve injury.

    PubMed

    Zegrea, I; Chivu, Laura Ioana; Albu, Mădălina Georgiana; Zamfirescu, D; Chivu, R D; Ion, Daniela Adriana; Lascăr, I

    2012-01-01

    The study of nerve regeneration and functional recovery of the injured peripheral nerves represents a worldwide subject of clinical and scientific research. Our team aimed to obtain the first guide for nerve regeneration, bioartificial and biodegradable, using exclusively Romanian resources and having the advantages of price and quality, over the imported nerve conduits already used in clinical practice. First steps of this project consisted in obtaining the prototype of nerve guide conduit and its' testing in vitro and in vivo. Tests of physicochemical characterization, FTIR (Fourier Transform Infrared) spectrometry, thermal analysis (differential calorimetry, thermo-gravimetry), electron microscopy, water absorption and enzymatic degradation of the obtained prototype were followed by in vivo testing. The first results, obtained on a group of Brown Norway rats who suffered experimental lesions of 1 cm at the level of left sciatic nerve, which have then been repaired using the Romanian conduit prototype, are favorable in terms of biocompatibility, biodegradable capacity and support of nerve regeneration.

  18. Thermally Drawn Fibers as Nerve Guidance Scaffolds

    PubMed Central

    Koppes, Ryan A.; Park, Seongjun; Hood, Tiffany; Jia, Xiaoting; Poorheravi, Negin Abdolrahim; Achyuta, Anilkumar Harapanahalli; Fink, Yoel; Anikeeva, Polina

    2016-01-01

    Synthetic neural scaffolds hold promise to eventually replace nerve autografts for tissue repair following peripheral nerve injury. Despite substantial evidence for the influence of scaffold geometry and dimensions on the rate of axonal growth, systematic evaluation of these parameters remains a challenge due to limitations in materials processing. We have employed fiber drawing to engineer a wide spectrum of polymer-based neural scaffolds with varied geometries and core sizes. Using isolated whole dorsal root ganglia as an in vitro model system we have identified key features enhancing nerve growth within these fiber scaffolds. Our approach enabled straightforward integration of microscopic topography at the scale of nerve fascicles within the scaffold cores, which led to accelerated Schwann cell migration, as well as neurite growth and alignment. Our findings indicate that fiber drawing provides a scalable and versatile strategy for producing nerve guidance channels capable of controlling direction and accelerating the rate of axonal growth. PMID:26717246

  19. Thermally drawn fibers as nerve guidance scaffolds.

    PubMed

    Koppes, Ryan A; Park, Seongjun; Hood, Tiffany; Jia, Xiaoting; Abdolrahim Poorheravi, Negin; Achyuta, Anilkumar Harapanahalli; Fink, Yoel; Anikeeva, Polina

    2016-03-01

    Synthetic neural scaffolds hold promise to eventually replace nerve autografts for tissue repair following peripheral nerve injury. Despite substantial evidence for the influence of scaffold geometry and dimensions on the rate of axonal growth, systematic evaluation of these parameters remains a challenge due to limitations in materials processing. We have employed fiber drawing to engineer a wide spectrum of polymer-based neural scaffolds with varied geometries and core sizes. Using isolated whole dorsal root ganglia as an in vitro model system we have identified key features enhancing nerve growth within these fiber scaffolds. Our approach enabled straightforward integration of microscopic topography at the scale of nerve fascicles within the scaffold cores, which led to accelerated Schwann cell migration, as well as neurite growth and alignment. Our findings indicate that fiber drawing provides a scalable and versatile strategy for producing nerve guidance channels capable of controlling direction and accelerating the rate of axonal growth.

  20. Microtubular architecture of biodegradable polymer scaffolds.

    PubMed

    Ma, P X; Zhang, R

    2001-09-15

    It is a relatively new approach to generate tissues with mammalian cells and scaffolds (temporary synthetic extracellular matrices). Many tissues, such as nerve, muscle, tendon, ligament, blood vessel, bone, and teeth, have tubular or fibrous bundle architectures and anisotropic properties. In this work, we have designed and fabricated highly porous scaffolds from biodegradable polymers with a novel phase-separation technique to generate controllable parallel array of microtubular architecture. Porosity as high as 97% has been achieved. The porosity, diameter of the microtubules, the tubular morphology, and their orientation are controlled by the polymer concentration, solvent system, and temperature gradient. The mechanical properties of these scaffolds are anisotropic. Osteoprogenitor cells are seeded in these three-dimensional scaffolds and cultured in vitro. The cell distribution and the neo-tissue organization are guided by the microtubular architecture. The fabrication technique can be applied to a variety of polymers, therefore the degradation rate and cell--matrix interactions can be controlled by the chemical composition of the polymers and the incorporation of bioactive moieties. These microtubular scaffolds may be used to engineer a variety of tissues with anisotropic architecture and properties.

  1. Enhancement of Second-Harmonic Power Due to Self-Construction of an Anti-Guide Structure in a Thin-Film Waveguide of a Nonlinear-Optical Photoconducting Polymer

    NASA Astrophysics Data System (ADS)

    Sassa, Takafumi; Umegaki, Shinsuke

    1998-04-01

    A theoretical analysis, to explain the increase of the Cerenkov-radiation-type second-harmonic power with time in a thin-film waveguide of a nonlinear-optical photoconducting polymer, is given. An anti-guide structure, which confines both a fundamental wave and its second-harmonic wave, is gradually constructed by reorientation of the nonlinear-optical chromophores within the fundamental beam width in the thin-film polymer. The space-charge field formed by the initially weak second-harmonic wave itself causes the reorientation.

  2. Electrospun micro- and nanofiber tubes for functional nervous regeneration in sciatic nerve transections

    PubMed Central

    Panseri, Silvia; Cunha, Carla; Lowery, Joseph; Del Carro, Ubaldo; Taraballi, Francesca; Amadio, Stefano; Vescovi, Angelo; Gelain, Fabrizio

    2008-01-01

    Background Although many nerve prostheses have been proposed in recent years, in the case of consistent loss of nervous tissue peripheral nerve injury is still a traumatic pathology that may impair patient's movements by interrupting his motor-sensory pathways. In the last few decades tissue engineering has opened the door to new approaches;: however most of them make use of rigid channel guides that may cause cell loss due to the lack of physiological local stresses exerted over the nervous tissue during patient's movement. Electrospinning technique makes it possible to spin microfiber and nanofiber flexible tubular scaffolds composed of a number of natural and synthetic components, showing high porosity and remarkable surface/volume ratio. Results In this study we used electrospun tubes made of biodegradable polymers (a blend of PLGA/PCL) to regenerate a 10-mm nerve gap in a rat sciatic nerve in vivo. Experimental groups comprise lesioned animals (control group) and lesioned animals subjected to guide conduits implantated at the severed nerve stumps, where the tubular scaffolds are filled with saline solution. Four months after surgery, sciatic nerves failed to reconnect the two stumps of transected nerves in the control animal group. In most of the treated animals the electrospun tubes induced nervous regeneration and functional reconnection of the two severed sciatic nerve tracts. Myelination and collagen IV deposition have been detected in concurrence with regenerated fibers. No significant inflammatory response has been found. Neural tracers revealed the re-establishment of functional neuronal connections and evoked potential results showed the reinnervation of the target muscles in the majority of the treated animals. Conclusion Corroborating previous works, this study indicates that electrospun tubes, with no additional biological coating or drug loading treatment, are promising scaffolds for functional nervous regeneration. They can be knitted in meshes

  3. Nerves Regulate Cardiomyocyte Proliferation and Heart Regeneration.

    PubMed

    Mahmoud, Ahmed I; O'Meara, Caitlin C; Gemberling, Matthew; Zhao, Long; Bryant, Donald M; Zheng, Ruimao; Gannon, Joseph B; Cai, Lei; Choi, Wen-Yee; Egnaczyk, Gregory F; Burns, Caroline E; Burns, C Geoffrey; MacRae, Calum A; Poss, Kenneth D; Lee, Richard T

    2015-08-24

    Some organisms, such as adult zebrafish and newborn mice, have the capacity to regenerate heart tissue following injury. Unraveling the mechanisms of heart regeneration is fundamental to understanding why regeneration fails in adult humans. Numerous studies have revealed that nerves are crucial for organ regeneration, thus we aimed to determine whether nerves guide heart regeneration. Here, we show using transgenic zebrafish that inhibition of cardiac innervation leads to reduction of myocyte proliferation following injury. Specifically, pharmacological inhibition of cholinergic nerve function reduces cardiomyocyte proliferation in the injured hearts of both zebrafish and neonatal mice. Direct mechanical denervation impairs heart regeneration in neonatal mice, which was rescued by the administration of neuregulin 1 (NRG1) and nerve growth factor (NGF) recombinant proteins. Transcriptional analysis of mechanically denervated hearts revealed a blunted inflammatory and immune response following injury. These findings demonstrate that nerve function is required for both zebrafish and mouse heart regeneration.

  4. Habilitation of facial nerve dysfunction after resection of a vestibular schwannoma.

    PubMed

    Rudman, Kelli L; Rhee, John S

    2012-04-01

    Facial nerve dysfunction after resection of a vestibular schwannoma is one of the most common indications for facial nerve habilitation. This article presents an overview of common and emerging management options for facial habilitation following resection of a vestibular schwannoma. Immediate and delayed nerve repair options, as well as adjunctive surgical, medical, and physical therapies for facial nerve dysfunction, are discussed. Two algorithms are provided as guides for the assessment and treatment of facial nerve paralysis after resection of vestibular schwannoma.

  5. Nerve conduction velocity

    MedlinePlus

    ... polyneuropathy Tibial nerve dysfunction Ulnar nerve dysfunction Any peripheral neuropathy can cause abnormal results. Damage to the spinal ... Herniated disk Lambert-Eaton syndrome Mononeuropathy Multiple ... azotemia Primary amyloidosis Radial nerve dysfunction Sciatica ...

  6. Nerve Impulses in Plants

    ERIC Educational Resources Information Center

    Blatt, F. J.

    1974-01-01

    Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

  7. Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration

    DTIC Science & Technology

    2013-01-01

    there was any dose response to the nanofibers, by varying the density of nanofibers per unit area of conduit by electrospinning for different lengths...the films with nanofibers by electrospinning directly upon them, requiring the films to be sufficiently strong to not break when rotated at over 1000...within the conduits. Next, we will use the electrospinning parameters optimized over the last year to spin larger and smaller fibers (1200 nm and

  8. Normal and sonographic anatomy of selected peripheral nerves. Part II: Peripheral nerves of the upper limb

    PubMed Central

    Sudoł-Szopińska, Iwona

    2012-01-01

    The ultrasonographic examination is frequently used for imaging peripheral nerves. It serves to supplement the physical examination, electromyography, and magnetic resonance imaging. As in the case of other USG imaging studies, the examination of peripheral nerves is non-invasive, well-tolerated by patients, and relatively inexpensive. Part I of this article series described in detail the characteristic USG picture of peripheral nerves and the proper examination technique, following the example of the median nerve. This nerve is among the most often examined peripheral nerves of the upper limb. This part presents describes the normal anatomy and ultrasound picture of the remaining large nerve branches in the upper extremity and neck – the spinal accessory nerve, the brachial plexus, the suprascapular, axillary, musculocutaneous, radial and ulnar nerves. Their normal anatomy and ultrasonographic appearance have been described, including the division into individual branches. For each of them, specific reference points have been presented, to facilitate the location of the set trunk and its further monitoring. Sites for the application of the ultrasonographic probe at each reference point have been indicated. In the case of the ulnar nerve, the dynamic component of the examination was emphasized. The text is illustrated with images of probe positioning, diagrams of the normal course of the nerves as well as a series of ultrasonographic pictures of normal nerves of the upper limb. This article aims to serve as a guide in the ultrasound examination of the peripheral nerves of the upper extremity. It should be remembered that a thorough knowledge of the area's topographic anatomy is required for this type of examination. PMID:26674017

  9. A novel internal fixator device for peripheral nerve regeneration.

    PubMed

    Chuang, Ting-Hsien; Wilson, Robin E; Love, James M; Fisher, John P; Shah, Sameer B

    2013-06-01

    Recovery from peripheral nerve damage, especially for a transected nerve, is rarely complete, resulting in impaired motor function, sensory loss, and chronic pain with inappropriate autonomic responses that seriously impair quality of life. In consequence, strategies for enhancing peripheral nerve repair are of high clinical importance. Tension is a key determinant of neuronal growth and function. In vitro and in vivo experiments have shown that moderate levels of imposed tension (strain) can encourage axonal outgrowth; however, few strategies of peripheral nerve repair emphasize the mechanical environment of the injured nerve. Toward the development of more effective nerve regeneration strategies, we demonstrate the design, fabrication, and implementation of a novel, modular nerve-lengthening device, which allows the imposition of moderate tensile loads in parallel with existing scaffold-based tissue engineering strategies for nerve repair. This concept would enable nerve regeneration in two superposed regimes of nerve extension--traditional extension through axonal outgrowth into a scaffold and extension in intact regions of the proximal nerve, such as that occurring during growth or limb-lengthening. Self-sizing silicone nerve cuffs were fabricated to grip nerve stumps without slippage, and nerves were deformed by actuating a telescoping internal fixator. Poly(lactic co-glycolic) acid (PLGA) constructs mounted on the telescoping rods were apposed to the nerve stumps to guide axonal outgrowth. Neuronal cells were exposed to PLGA using direct contact and extract methods, and they exhibited no signs of cytotoxic effects in terms of cell morphology and viability. We confirmed the feasibility of implanting and actuating our device within a sciatic nerve gap and observed axonal outgrowth following device implantation. The successful fabrication and implementation of our device provides a novel method for examining mechanical influences on nerve regeneration.

  10. A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers

    PubMed Central

    Yalom, Anisa; Berns, Eric J.; Stephanopoulos, Nicholas; McClendon, Mark T.; Segovia, Luis A.; Spigelman, Igor; Stupp, Samuel I.; Jarrahy, Reza

    2014-01-01

    Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may

  11. Ultrasonography Evaluation of Vulnerable Vessels Around Cervical Nerve Roots During Selective Cervical Nerve Root Block

    PubMed Central

    2017-01-01

    Objective To evaluate the prevalence of vulnerable blood vessels around cervical nerve roots before cervical nerve root block in the clinical setting. Methods This retrospective study included 74 patients with cervical radiculopathy who received an ultrasonography-guided nerve block at an outpatient clinic from July 2012 to July 2014. Before actual injection of the steroid was performed, we evaluated the vulnerable blood vessels around each C5, C6, and C7 nerve root of each patient's painful side, with Doppler ultrasound. Results Out of 74 cases, the C5 level had 2 blood vessels (2.7%), the C6 level had 4 blood vessels (5.45%), and the C7 level had 6 blood vessels (8.11%) close to each targeted nerve root. Moreover, the C5 level had 2 blood vessels (2.7%), the C6 level 5 blood vessels (6.75%), and the C7 level had 4 blood vessels (5.45%) at the site of an imaginary needle's projected pathway to the targeted nerve root, as revealed by axial transverse ultrasound imaging with color Doppler imaging. In total, the C5 level had 4 blood vessels (5.45%), the C6 level 9 blood vessels (12.16%), and the C7 level 10 had blood vessels (13.51%) either at the targeted nerve root or at the site of the imaginary needle's projected pathway to the targeted nerve root. There was an unneglectable prevalence of vulnerable blood vessels either at the targeted nerve root or at the site of the needle' projected pathway to the nerve root. Also, it shows a higher prevalence of vulnerable blood vessels either at the targeted nerve root or at the site of an imaginary needle's projected pathway to the nerve root as the spinal nerve root level gets lower. Conclusion To prevent unexpected critical complications involving vulnerable blood vessel injury during cervical nerve root block, it is recommended to routinely evaluate for the presence of vulnerable blood vessels around each cervical nerve root using Doppler ultrasound imaging before the cervical nerve root block, especially for the lower

  12. A nanofibrous PHBV tube with Schwann cell as artificial nerve graft contributing to rat sciatic nerve regeneration across a 30-mm defect bridge.

    PubMed

    Biazar, Esmaeil; Heidari Keshel, Saeed

    2013-02-01

    A nanofibrous PHBV nerve conduit has been used to evaluate its efficiency based on the promotion of nerve regeneration in rats. The designed conduits were investigated by physical, mechanical and microscopic analyses. The conduits were implanted into a 30-mm gap in the sciatic nerves of the rats. Four months after surgery, the regenerated nerves were evaluated by macroscopic assessments and histology. This polymeric conduit had sufficiently high mechanical properties to serve as a nerve guide. The results demonstrated that in the nanofibrous graft with cells, the sciatic nerve trunk had been reconstructed with restoration of nerve continuity and formatted nerve fibers with myelination. For the grafts especially the nanofibrous conduits with cells, muscle cells of gastrocnemius on the operated side were uniform in their size and structures. This study proves the feasibility of artificial conduit with Schwann cells for nerve regeneration by bridging a longer defect in a rat model.

  13. Optic Nerve Sheath Meningiomas.

    PubMed

    Radhakrishnan, Sunita; Lee, Michael S

    2005-01-01

    Optic nerve sheath meningiomas (ONSMs) grow slowly and, if untreated, patients may have stable visual function for up to several years. Treatment of an ONSM may lead to vision loss (radiation retinopathy or optic neuropathy). Therefore, observation is recommended for a patient with ONSM and relatively preserved visual acuity, color vision, pupils, and visual fields. Follow-up every 4 to 6 months initially is recommended extending to annual examinations if visual function and tumor size remain stable for a few years. Neuroimaging can be repeated every 12 months. An undisputed decline in visual function or any intracranial extension warrants treatment of the ONSM. The treatment of choice for a tumor confined to the orbit is stereotactic fractionated radiation. Stereotactic fractionated radiation uses multiple small doses of radiation using tight margins. A reasonable alternative, three-dimensional conformal fractionated radiation uses computed tomography-guided planning but usually requires wider margins. Conventional radiation uses much wider margins and would not be recommended for treatment of ONSM. The radiation can be administered during 5 to 6 weeks in 28 daily fractions of 1.8 to 2 Gy/fraction to a total of 50.4 to 56 Gy. Many patients have improvement or stabilization of their visual function. Gamma knife radiosurgery does not have a role in ONSM because the required dose is toxic to the optic nerve. A tumor that extends intracranially may be treated with fractionated radiation if any vision remains. Surgical excision can be considered for significant intracranial extension but this often leads to complete vision loss in the ipsilateral eye. A blind, disfigured eye also may be treated with en bloc surgical resection of the meningioma.

  14. Nerve Injuries in Athletes.

    ERIC Educational Resources Information Center

    Collins, Kathryn; And Others

    1988-01-01

    Over a two-year period this study evaluated the condition of 65 athletes with nerve injuries. These injuries represent the spectrum of nerve injuries likely to be encountered in sports medicine clinics. (Author/MT)

  15. Electromechanical Nerve Stimulator

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

    1993-01-01

    Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

  16. Induction of rat facial nerve regeneration by functional collagen scaffolds.

    PubMed

    Cao, Jiani; Xiao, Zhifeng; Jin, Wei; Chen, Bing; Meng, Danqing; Ding, Wenyong; Han, Sufang; Hou, Xiaoshan; Zhu, Tiansheng; Yuan, Baoyu; Wang, Jing; Liang, Weibang; Dai, Jianwu

    2013-01-01

    Nerve conduit provides a promising strategy for nerve regeneration, and the proper microenvironment in the lumen could improve the regeneration. Our previous work had demonstrated that linear ordered collagen scaffold (LOCS) could effectively guide the oriented growth of axons. Laminin is known as an important nerve growth promoting factor and can facilitate the growth cone formation. In addition, ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) can effectively improve the nerve regeneration after nerve injuries. However, in practice, diffusion caused by the body fluids is the major obstacle in their applications. To retain CNTF or BDNF on the scaffolds, we produced collagen binding CNTF (CBD-CNTF), collagen binding BDNF (CBD-BDNF) and laminin binding CNTF (LBD-CNTF), laminin binding BDNF (LBD-BDNF) respectively. In this work, we developed laminin modified LOCS fibers (L × LOCS) by chemical cross-linking LOCS fibers with laminin. Collagen binding or laminin binding neurotrophic factors were combined with LOCS or L × LOCS, and then filled them into the collagen nerve conduit. They were found to guide the ordered growth of axons, and improve the nerve functional recovery in the rat facial nerve transection model. The combination of CNTF and BDNF greatly enhanced the facial nerve regeneration and functional recovery.

  17. The Anatomic Relationship of the Tibial Nerve to the Common Peroneal Nerve in the Popliteal Fossa: Implications for Selective Tibial Nerve Block in Total Knee Arthroplasty

    PubMed Central

    Silverman, Eric R.; Vydyanathan, Amaresh; Gritsenko, Karina; Shaparin, Naum; Singh, Nair; Downie, Sherry A.

    2017-01-01

    Background. A recently described selective tibial nerve block at the popliteal crease presents a viable alternative to sciatic nerve block for patients undergoing total knee arthroplasty. In this two-part investigation, we describe the effects of a tibial nerve block at the popliteal crease. Methods. In embalmed cadavers, after the ultrasound-guided dye injection the dissection revealed proximal spread of dye within the paraneural sheath. Consequentially, in the clinical study twenty patients scheduled for total knee arthroplasty received the ultrasound-guided selective tibial nerve block at the popliteal crease, which also resulted in proximal spread of local anesthetic. A sensorimotor exam was performed to monitor the effect on the peroneal nerve. Results. In the cadaver study, dye was observed to spread proximal in the paraneural sheath to reach the sciatic nerve. In the clinical observational study, local anesthetic was observed to spread a mean of 4.7 + 1.9 (SD) cm proximal to popliteal crease. A negative correlation was found between the excess spread of local anesthetic and bifurcation distance. Conclusions. There is significant proximal spread of local anesthetic following tibial nerve block at the popliteal crease with possibility of the undesirable motor blocks of the peroneal nerve. PMID:28260964

  18. Optic Nerve Pit

    MedlinePlus

    ... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Optic Nerve Pit What is optic nerve pit? An optic nerve pit is a ... may be seen in both eyes. How is optic pit diagnosed? If the pit is not affecting ...

  19. A Silk Fibroin/Collagen Nerve Scaffold Seeded with a Co-Culture of Schwann Cells and Adipose-Derived Stem Cells for Sciatic Nerve Regeneration.

    PubMed

    Xu, Yunqiang; Zhang, Zhenhui; Chen, Xuyi; Li, Ruixin; Li, Dong; Feng, Shiqing

    2016-01-01

    As a promising alternative to autologous nerve grafts, tissue-engineered nerve grafts have been extensively studied as a way to bridge peripheral nerve defects and guide nerve regeneration. The main difference between autogenous nerve grafts and tissue-engineered nerve grafts is the regenerative microenvironment formed by the grafts. If an appropriate regenerative microenvironment is provided, the repair of a peripheral nerve is feasible. In this study, to mimic the body's natural regenerative microenvironment closely, we co-cultured Schwann cells (SCs) and adipose-derived stem cells (ADSCs) as seed cells and introduced them into a silk fibroin (SF)/collagen scaffold to construct a tissue-engineered nerve conduit (TENC). Twelve weeks after the three different grafts (plain SF/collagen scaffold, TENC, and autograft) were transplanted to bridge 1-cm long sciatic nerve defects in rats, a series of electrophysiological examinations and morphological analyses were performed to evaluate the effect of the tissue-engineered nerve grafts on peripheral nerve regeneration. The regenerative outcomes showed that the effect of treatment with TENCs was similar to that with autologous nerve grafts but superior to that with plain SF/collagen scaffolds. Meanwhile, no experimental animals had inflammation around the grafts. Based on this evidence, our findings suggest that the TENC we developed could improve the regenerative microenvironment and accelerate nerve regeneration compared to plain SF/collagen and may serve as a promising strategy for peripheral nerve repair.

  20. Optic Nerve Elongation

    PubMed Central

    Alvi, Aijaz; Janecka, Ivo P.; Kapadia, Silloo; Johnson, Bruce L.; McVay, William

    1996-01-01

    The length of the optic nerves is a reflection of normal postnatal cranio-orbital development. Unilateral elongation of an optic nerve has been observed in two patients with orbital and skull base neoplasms. In the first case as compared to the patient's opposite, normal optic nerve, an elongated length of the involved optic nerve of 45 mm was present. The involved optic nerve in the second patient was 10 mm longer than the normal opposite optic nerve. The visual and extraocular function was preserved in the second patient. The first patient had only light perception in the affected eye. In this paper, the embryology, anatomy, and physiology of the optic nerve and its mechanisms of stretch and repair are discussed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10Figure 11Figure 13 PMID:17170975

  1. Assessment of nerve morphology in nerve activation during electrical stimulation

    NASA Astrophysics Data System (ADS)

    Gomez-Tames, Jose; Yu, Wenwei

    2013-10-01

    The distance between nerve and stimulation electrode is fundamental for nerve activation in Transcutaneous Electrical Stimulation (TES). However, it is not clear the need to have an approximate representation of the morphology of peripheral nerves in simulation models and its influence in the nerve activation. In this work, depth and curvature of a nerve are investigated around the middle thigh. As preliminary result, the curvature of the nerve helps to reduce the simulation amplitude necessary for nerve activation from far field stimulation.

  2. Trends in the design of nerve guidance channels in peripheral nerve tissue engineering.

    PubMed

    Chiono, Valeria; Tonda-Turo, Chiara

    2015-08-01

    The current trend of peripheral nerve tissue engineering is the design of advanced nerve guidance channels (NGCs) acting as physical guidance for regeneration of nerves across lesions. NGCs should present multifunctional properties aiming to direct the sprouting of axons from the proximal nerve end, to concentrate growth factors secreted by the injured nerve ends, and to reduce the ingrowth of scar tissue into the injury site. A critical aspect in the design of NGCs is conferring them the ability to provide topographic, chemotactic and haptotactic cues that lead to functional nerve regeneration thus increasing the axon growth rate and avoiding or minimizing end-organ (e.g. muscle) atrophy. The present work reviews the recent state of the art in NGCs engineering and defines the external guide and internal fillers structural and compositional requirements that should be satisfied to improve nerve regeneration, especially in the case of large gaps (>2 cm). Techniques for NGCs fabrication were described highlighting the innovative approaches direct to enhance the regeneration of axon stumps compared to current clinical treatments. Furthermore, the possibility to apply stem cells as internal cues to the NGCs was discussed focusing on scaffold properties necessary to ensure cell survival. Finally, the optimized features for NGCs design were summarized showing as multifunctional cues are needed to produce NGCs having improved results in clinics.

  3. Different Learning Curves for Axillary Brachial Plexus Block: Ultrasound Guidance versus Nerve Stimulation

    PubMed Central

    Luyet, C.; Schüpfer, G.; Wipfli, M.; Greif, R.; Luginbühl, M.; Eichenberger, U.

    2010-01-01

    Little is known about the learning of the skills needed to perform ultrasound- or nerve stimulator-guided peripheral nerve blocks. The aim of this study was to compare the learning curves of residents trained in ultrasound guidance versus residents trained in nerve stimulation for axillary brachial plexus block. Ten residents with no previous experience with using ultrasound received ultrasound training and another ten residents with no previous experience with using nerve stimulation received nerve stimulation training. The novices' learning curves were generated by retrospective data analysis out of our electronic anaesthesia database. Individual success rates were pooled, and the institutional learning curve was calculated using a bootstrapping technique in combination with a Monte Carlo simulation procedure. The skills required to perform successful ultrasound-guided axillary brachial plexus block can be learnt faster and lead to a higher final success rate compared to nerve stimulator-guided axillary brachial plexus block. PMID:21318138

  4. Case report: computed tomography scan-guided Gasserian ganglion injection of dexamethasone and lidocaine for the treatment of recalcitrant pain associated with herpes simplex type 1 infection of the ophthalmic division of the trigeminal nerve.

    PubMed

    Candido, Kenneth D; Germanovich, Andrew; Ghaly, Ramsis F; Gorelick, Gleb H; Knezevic, Nebojsa Nick

    2011-01-01

    We describe the case of a 17-year-old boy with dermatologic herpes simplex virus-1 outbreaks with incapacitating facial pain requiring multiple hospitalizations. He failed to respond to aggressive treatments including antiviral drugs, opioid analgesics, stellate ganglion, and supraorbital and supratrochlear nerve blocks. The patient elected to undergo dexamethasone and lidocaine Gasserian ganglion block under computed tomography-scan guidance. He had immediate and complete relief of his pain for the first time in almost 2 years. The patient remained pain free during 6-month follow-up visits. This is the first reported use of Gasserian ganglion block for treatment of herpes simplex virus-1 infection of the trigeminal nerve.

  5. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  6. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  7. Lateralization Technique and Inferior Alveolar Nerve Transposition

    PubMed Central

    Sanches, Marco Antonio; Ramalho, Gabriel Cardoso; Manzi, Marcello Roberto

    2016-01-01

    Bone resorption of the posterior mandible can result in diminished bone edge and, therefore, the installation of implants in these regions becomes a challenge, especially in the presence of the mandibular canal and its contents, the inferior alveolar nerve. Several treatment alternatives are suggested: the use of short implants, guided bone regeneration, appositional bone grafting, distraction osteogenesis, inclined implants tangential to the mandibular canal, and the lateralization of the inferior alveolar nerve. The aim was to elucidate the success rate of implants in the lateralization technique and in inferior alveolar nerve transposition and to determine the most effective sensory test. We conclude that the success rate is linked to the possibility of installing implants with long bicortical anchor which favors primary stability and biomechanics. PMID:27433360

  8. Essential regional nerve blocks for the dermatologist: part 1.

    PubMed

    Davies, T; Karanovic, S; Shergill, B

    2014-10-01

    The aim of this two-part series is to provide an up-to-date review of essential regional nerve blocks for dermatological practice. In Part 1, we give a concise overview of local anaesthetics and their potential complications, as well as the relevant anatomy and cutaneous innervation of the face and scalp. This culminates in a step-by-step practical guide to performing each nerve block.

  9. Tibial nerve intraneural ganglion cyst in a 10-year-old boy.

    PubMed

    Squires, Judy H; Emery, Kathleen H; Johnson, Neil; Sorger, Joel

    2014-04-01

    Intraneural ganglion cysts are uncommon cystic lesions of peripheral nerves that are typically encountered in adults. In the lower extremity, the peroneal nerve is most frequently affected with involvement of the tibial nerve much less common. This article describes a tibial intraneural ganglion cyst in a 10-year-old boy. Although extremely rare, intraneural ganglion cysts of the tibial nerve should be considered when a nonenhancing cystic structure with intra-articular extension is identified along the course of the nerve. This report also details the unsuccessful attempt at percutaneous treatment with US-guided cyst aspiration and steroid injection, an option recently reported as a viable alternative to open surgical resection.

  10. High aspect ratio template and method for producing same for central and peripheral nerve repair

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeff S. (Inventor); Tuszynski, Mark Henry (Inventor); Gros, Thomas (Inventor); Chan, Christina (Inventor); Mehrotra, Sumit (Inventor)

    2011-01-01

    Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers. The scaffolds may be used in, among other applications, the repair of central and peripheral nerves. Scaffolds for the repair of peripheral nerves may include a reservoir for the sustained release of nerve growth factor. The scaffolds may also include a multifunctional polyelectrolyte layer for the sustained release of nerve growth factor and enhance biocompatibility.

  11. Utilization of theoretical studies of the imprinting ratio to guide experimental research into the molecular imprinted polymers formed using enrofloxacin and methacrylic acid.

    PubMed

    Liu, Junbo; Dai, Zhengqiang; Li, Bo; Tang, Shanshan; Jin, Ruifa

    2014-10-01

    Computational approaches have been suggested as rational and fast methods for optimizing imprinting ratios. The B3LYP/6-31 g(d,p) level was applied to simulate the self-assembled system of molecularly imprinted polymers (MIPs) formed by enrofloxacin (ENRO) and methacrylic acid (MAA). Geometry optimization, the bonding situation, and the binding energies involved were studied to determine the impact of varying the imprinting ratio on the recognition characteristics. These theoretical results showed that the compound with an ENRO:MAA ratio of 1:7 had the lowest binding energy and the most stable structure. MIPs with different imprinting ratios of ENRO to MAA were then prepared in order to study the binding capacities of the polymers experimentally. The experimental and theoretically calculated results for these polymers were found to be consistent with each other. In dynamic adsorption experiments on the MIPs, the adsorption reaction was observed to reach a balanced state after 120 min. Analysis of the Scatchard plot revealed that the dissociation constant (K d) and the apparent maximum binding capacity (Q max) of MIPs with high-affinity sites were 451.67 mg/L and 42.23 mg/g, respectively, whereas the dissociation constant and apparent maximum binding capacity of MIPs with low-affinity sites were 883.39 mg/L and 73.15 mg/g, respectively. The quantity of ENRO adsorbed onto the MIPs was considerably higher than the quantities of ciprofloxacin (CIP) and ofloxacin (OFL) adsorbed, indicating that these MIPs have a much higher specific absorption capacity than the corresponding non-imprinted polymers.

  12. Peripheral nerve surgery.

    PubMed

    McQuarrie, I G

    1985-05-01

    In treating the three main surgical problems of peripheral nerves--nerve sheath tumors, entrapment neuropathies, and acute nerve injuries--the overriding consideration is the preservation and restoration of neurologic function. Because of this, certain other principles may need to be compromised. These include achieving a gross total excision of benign tumors, employing conservative therapy as long as a disease process is not clearly progressing, and delaying repair of a nerve transection until the skin wound has healed. Only three pathophysiologic processes need be considered: neurapraxia (focal segmental dymyelination), axonotmesis (wallerian degeneration caused by a lesion that does not disrupt fascicles of nerve fibers), and neurotmesis (wallerian degeneration caused by a lesion that interrupts fascicles). With nerve sheath tumors and entrapment neuropathies, the goal is minimize the extent to which neurapraxia progresses to axonotmesis. The compressive force is relieved without carrying out internal neurolysis, a procedure that is poorly tolerated, presumably because a degree of nerve ischemia exists with any long-standing compression. When the nerve has sustained blunt trauma (through acute compression, percussion, or traction), the result can be a total loss of function and an extensive neuroma-in-continuity (scarring within the nerve). However, the neural pathophysiology may amount to nothing more than axonotmesis. Although this lesion, in time, leads to full and spontaneous recovery, it must be differentiated from the neuroma-in-continuity that contains disrupted fascicles requiring surgery. Finally, with open nerve transection, the priority is to match the fascicles of the proximal stump with those of the distal stump, a goal that is best achieved if primary neurorrhaphy is carried out.

  13. Preoperative transcutaneous electrical nerve stimulation for localizing superficial nerve paths.

    PubMed

    Natori, Yuhei; Yoshizawa, Hidekazu; Mizuno, Hiroshi; Hayashi, Ayato

    2015-12-01

    During surgery, peripheral nerves are often seen to follow unpredictable paths because of previous surgeries and/or compression caused by a tumor. Iatrogenic nerve injury is a serious complication that must be avoided, and preoperative evaluation of nerve paths is important for preventing it. In this study, transcutaneous electrical nerve stimulation (TENS) was used for an in-depth analysis of peripheral nerve paths. This study included 27 patients who underwent the TENS procedure to evaluate the peripheral nerve path (17 males and 10 females; mean age: 59.9 years, range: 18-83 years) of each patient preoperatively. An electrode pen coupled to an electrical nerve stimulator was used for superficial nerve mapping. The TENS procedure was performed on patients' major peripheral nerves that passed close to the surgical field of tumor resection or trauma surgery, and intraoperative damage to those nerves was apprehensive. The paths of the target nerve were detected in most patients preoperatively. The nerve paths of 26 patients were precisely under the markings drawn preoperatively. The nerve path of one patient substantially differed from the preoperative markings with numbness at the surgical region. During surgery, the nerve paths could be accurately mapped preoperatively using the TENS procedure as confirmed by direct visualization of the nerve. This stimulation device is easy to use and offers highly accurate mapping of nerves for surgical planning without major complications. The authors conclude that TENS is a useful tool for noninvasive nerve localization and makes tumor resection a safe and smooth procedure.

  14. The lower cranial nerves: IX, X, XI, XII.

    PubMed

    Sarrazin, J-L; Toulgoat, F; Benoudiba, F

    2013-10-01

    The lower cranial nerves innervate the pharynx and larynx by the glossopharyngeal (CN IX) and vagus (CN X) (mixed) nerves, and provide motor innervation of the muscles of the neck by the accessory nerve (CN XI) and the tongue by the hypoglossal nerve (CN XII). The symptomatology provoked by an anomaly is often discrete and rarely in the forefront. As with all cranial nerves, the context and clinical examinations, in case of suspicion of impairment of the lower cranial nerves, are determinant in guiding the imaging. In fact, the impairment may be located in the brain stem, in the peribulbar cisterns, in the foramens or even in the deep spaces of the face. The clinical localization of the probable seat of the lesion helps in choosing the adapted protocol in MRI and eventually completes it with a CT-scan. In the bulb, the intra-axial pathology is dominated by brain ischemia (in particular, with Wallenberg syndrome) and multiple sclerosis. Cisternal pathology is tumoral with two tumors, schwannoma and meningioma. The occurrence is much lower than in the cochleovestibular nerves as well as the leptomeningeal nerves (infectious, inflammatory or tumoral). Finally, foramen pathology is tumoral with, outside of the usual schwannomas and meningiomas, paragangliomas. For radiologists, fairly hesitant to explore these lower cranial pairs, it is necessary to be familiar with (or relearn) the anatomy, master the exploratory technique and be aware of the diagnostic possibilities.

  15. Pathophysiology of nerve regeneration and nerve reconstruction in burned patients.

    PubMed

    Coert, J Henk

    2010-08-01

    In extensive burns peripheral nerves can be involved. The injury to the nerve can be direct by thermal or electrical burns, but nerves can also be indirectly affected by the systemic reaction that follows the burn. Mediators will be released causing a neuropathy to nerves remote from the involved area. Involved mediators and possible therapeutic options will be discussed. In burned patients nerves can be reconstructed using autologous nerve grafts or nerve conduits. A key factor is an adequate wound debridement and a well-vascularized bed to optimize the outgrowth of the axons. Early free tissue transfers have shown promising results.

  16. Glossopharyngeal Nerve Schwannoma

    PubMed Central

    Puzzilli, F.; Mastronardi, L.; Agrillo, U.; Nardi, P.

    1999-01-01

    Complete resection with conservation of cranial nerves is the primary goal of contemporary surgery for lower cranial nerve tumors. We describe the case of a patient with a schwannoma of the left glossopharyngeal nerve, operated on in our Neurosurgical Unit. The far lateral approach combined with laminectomy of the posterior arch of C1 was done in two steps. The procedure allowed total tumor resection and was found to be better than classic unilateral suboccipital or combined supra- and infratentorial approaches. The advantages and disadvantages of the far lateral transcondylar approach, compared to the other more common approaches, are discussed. ImagesFigure 1Figure 2 PMID:17171083

  17. Multispectral photoacoustic imaging of nerves with a clinical ultrasound system

    NASA Astrophysics Data System (ADS)

    Mari, Jean Martial; West, Simeon; Beard, Paul C.; Desjardins, Adrien E.

    2014-03-01

    Accurate and efficient identification of nerves is of great importance during many ultrasound-guided clinical procedures, including nerve blocks and prostate biopsies. It can be challenging to visualise nerves with conventional ultrasound imaging, however. One of the challenges is that nerves can have very similar appearances to nearby structures such as tendons. Several recent studies have highlighted the potential of near-infrared optical spectroscopy for differentiating nerves and adjacent tissues, as this modality can be sensitive to optical absorption of lipids that are present in intra- and extra-neural adipose tissue and in the myelin sheaths. These studies were limited to point measurements, however. In this pilot study, a custom photoacoustic system with a clinical ultrasound imaging probe was used to acquire multi-spectral photoacoustic images of nerves and tendons from swine ex vivo, across the wavelength range of 1100 to 1300 nm. Photoacoustic images were processed and overlaid in colour onto co-registered conventional ultrasound images that were acquired with the same imaging probe. A pronounced optical absorption peak centred at 1210 nm was observed in the photoacoustic signals obtained from nerves, and it was absent in those obtained from tendons. This absorption peak, which is consistent with the presence of lipids, provides a novel image contrast mechanism to significantly enhance the visualization of nerves. In particular, image contrast for nerves was up to 5.5 times greater with photoacoustic imaging (0.82 +/- 0.15) than with conventional ultrasound imaging (0.148 +/- 0.002), with a maximum contrast of 0.95 +/- 0.02 obtained in photoacoustic mode. This pilot study demonstrates the potential of photoacoustic imaging to improve clinical outcomes in ultrasound-guided interventions in regional anaesthesia and interventional oncology.

  18. An animal model of peripheral nerve regeneration after the application of a collagen-polyvinyl alcohol scaffold and mesenchymal stem cells.

    PubMed

    Marinescu, Silviu Adrian; Zărnescu, Otilia; Mihai, Ioana Ruxandra; Giuglea, Carmen; Sinescu, Ruxandra Diana

    2014-01-01

    Extensive nerve injuries often leading to nerve gaps can benefit, besides the gold standard represented by autologous nerve grafts, by the inciting field of tissue engineering. To enhance the role of biomaterials in nerve regeneration, the nerve conduits are associated with Schwann or Schwann-like cells. In this study, we evaluated rat sciatic nerve regeneration, by using a biodegradable nerve guide composed of Collagen (COL) and Polyvinyl Alcohol (PVA), associated with mesenchymal stem cells (MSC). After the exposure of the rat sciatic nerve, a nerve gap was created by excising 1 cm of the nerve. Three experimental groups were used for nerve gap bridging: autografts, nerve conduits filled with medium culture and nerve conduits filled with MSC. The methods of sensory and motor assessment consisted of the functional evaluation of sciatic nerve recovery - toe-spread, pinprick tests and gastrocnemius muscle index (GMI). The histological and immunocytochemical analysis of the probes that were harvested from the repair site was performed at 12 weeks. Successful nerve regeneration was noted in all three groups at the end of the 12th week. The functional and immunocytochemical results suggested that COL-PVA tubes supported with mesenchymal stem cells could be considered similar to autologous nerve grafts in peripheral nerve regeneration, without the drawbacks of the last ones. The functional results were better for the autografts and the ultrastructural data were better for the nerve conduits, but there were not noticed any statistical differences.

  19. Degenerative Nerve Diseases

    MedlinePlus

    Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical ...

  20. Optic Nerve Imaging

    MedlinePlus

    ... machines can help monitor and detect loss of optic nerve fibers. The Heidelberg Retina Tomograph (HRT) is a special ... keeping organized, you can establish a routine that works for you. Read more » Are You at Risk ...

  1. Axillary nerve dysfunction

    MedlinePlus

    ... Causes Axillary nerve dysfunction is a form of peripheral neuropathy . It occurs when there is damage to the ... Multiple mononeuropathy Muscle function loss Numbness and tingling Peripheral neuropathy Systemic Review Date 2/3/2015 Updated by: ...

  2. Tibial nerve dysfunction

    MedlinePlus

    ... Tibial nerve dysfunction is an unusual form of peripheral neuropathy . It occurs when there is damage to the ... PA: Elsevier Saunders; 2012:chap 76. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  3. Vagus Nerve Stimulation.

    PubMed

    Howland, Robert H

    2014-06-01

    The vagus nerve is a major component of the autonomic nervous system, has an important role in the regulation of metabolic homeostasis, and plays a key role in the neuroendocrine-immune axis to maintain homeostasis through its afferent and efferent pathways. Vagus nerve stimulation (VNS) refers to any technique that stimulates the vagus nerve, including manual or electrical stimulation. Left cervical VNS is an approved therapy for refractory epilepsy and for treatment resistant depression. Right cervical VNS is effective for treating heart failure in preclinical studies and a phase II clinical trial. The effectiveness of various forms of non-invasive transcutaneous VNS for epilepsy, depression, primary headaches, and other conditions has not been investigated beyond small pilot studies. The relationship between depression, inflammation, metabolic syndrome, and heart disease might be mediated by the vagus nerve. VNS deserves further study for its potentially favorable effects on cardiovascular, cerebrovascular, metabolic, and other physiological biomarkers associated with depression morbidity and mortality.

  4. Ulnar nerve damage (image)

    MedlinePlus

    ... is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where it crosses the elbow, so prolonged pressure on the elbow or entrapment ...

  5. Optic Nerve Disorders

    MedlinePlus

    ... of optic nerve disorders, including: Glaucoma is a group of diseases that are the leading cause of blindness in the United States. Glaucoma usually happens when the fluid pressure inside the eyes slowly rises and damages the ...

  6. Nerve Damage (Diabetic Neuropathies)

    MedlinePlus

    ... may include numbness or insensitivity to pain or temperature a tingling, burning, or prickling sensation sharp pains ... from working properly, the body cannot regulate its temperature as it should. Nerve damage can also cause ...

  7. Diabetes and nerve damage

    MedlinePlus

    Diabetic neuropathy; Diabetes - neuropathy; Diabetes - peripheral neuropathy ... In people with diabetes, the body's nerves can be damaged by decreased blood flow and a high blood sugar level. This condition is ...

  8. Vagus Nerve Stimulation

    PubMed Central

    Howland, Robert H.

    2014-01-01

    The vagus nerve is a major component of the autonomic nervous system, has an important role in the regulation of metabolic homeostasis, and plays a key role in the neuroendocrine-immune axis to maintain homeostasis through its afferent and efferent pathways. Vagus nerve stimulation (VNS) refers to any technique that stimulates the vagus nerve, including manual or electrical stimulation. Left cervical VNS is an approved therapy for refractory epilepsy and for treatment resistant depression. Right cervical VNS is effective for treating heart failure in preclinical studies and a phase II clinical trial. The effectiveness of various forms of non-invasive transcutaneous VNS for epilepsy, depression, primary headaches, and other conditions has not been investigated beyond small pilot studies. The relationship between depression, inflammation, metabolic syndrome, and heart disease might be mediated by the vagus nerve. VNS deserves further study for its potentially favorable effects on cardiovascular, cerebrovascular, metabolic, and other physiological biomarkers associated with depression morbidity and mortality. PMID:24834378

  9. Diabetic Nerve Problems

    MedlinePlus

    ... at the wrong times. This damage is called diabetic neuropathy. Over half of people with diabetes get it. ... you change positions quickly Your doctor will diagnose diabetic neuropathy with a physical exam and nerve tests. Controlling ...

  10. Comparison of the Effect of Lidocaine versus a Lidocaine-Bupivacaine Combination in a Periprostatic Nerve Block Undergoing Transrectal Ultrasound-Guided Prostate Biopsy: A Double-Blind Randomized Controlled Trial

    PubMed Central

    Yilmaz, Ali H.; Ziypak, Elif; Ziypak, Tevfik; Aksoy, Mehmet; Adanur, Senol; Kocakgol, Hüseyin; Demirdogen, Saban O.; Polat, Ozkan

    2016-01-01

    Introduction To determine whether a combination of the long acting local anesthetic, bupivacaine, and lidocaine is better than lidocaine alone in the long-term pain control, which is a short-acting anesthetic. Materials and Methods In group 1, periprostatic nerve block was applied to both neurovascular areas with 2% lidocaine (5 ml) in an isotonic solution (5 ml). In group 2, the combination of 2% lidocaine (5 ml) and 5mg/ml bupivacaine (5 ml) was used for the PPNB. Results In the first 30 minutes the mean VAS scores of groups 1 and 2 were 2.1 ± 0.2 and 1.2 ± 0.1, respectively (p = 0.002). VAS scores of group II determined at 1, 2, 4, 6, and 8 hours after the biopsy were significantly lower since it was (p < 0.05). Conclusion While periprostatic nerve block for late phase pain control, applying a combination of a long-acting local anesthetic, such as bupivacaine, is effective in terms of pain control and patient comfort. PMID:27867334

  11. Nerves and Tissue Repair.

    DTIC Science & Technology

    1992-05-21

    complete dependence on nerves. Organ culture of sciatic nerves, combined with an assay for axolotl transferrin developed earlier, allows quantitative study...axonal release of various unknown proteins. Combining this approach with the ELISA for quantitative measurement of axolotl transferrin developed with...light microscope autoradiographic analysis following binding of radiolabelled Tf. Studies of Tf synthesis will employ cDNA probes for axolotl Tf mRNA

  12. Traumatic facial nerve injury.

    PubMed

    Lee, Linda N; Lyford-Pike, Sofia; Boahene, Kofi Derek O

    2013-10-01

    Facial nerve trauma can be a devastating injury resulting in functional deficits and psychological distress. Deciding on the optimal course of treatment for patients with traumatic facial nerve injuries can be challenging, as there are many critical factors to be considered for each patient. Choosing from the great array of therapeutic options available can become overwhelming to both patients and physicians, and in this article, the authors present a systematic approach to help organize the physician's thought process.

  13. Optic nerve aspergillosis.

    PubMed

    Yuan, Lisi; Prayson, Richard A

    2015-07-01

    We report a 55-year-old woman with optic nerve Aspergillosis. Aspergillus is an ubiquitous airborne saprophytic fungus. Inhaled Aspergillus conidia are normally eliminated in the immunocompetent host by innate immune mechanisms; however, in immunosuppressed patients, they can cause disease. The woman had a past medical history of hypertension and migraines. She presented 1 year prior to death with a new onset headache behind the left eye and later developed blurred vision and scotoma. A left temporal artery biopsy was negative for giant cell arteritis. One month prior to the current admission, she had an MRI showing optic nerve thickening with no other findings. Because of the visual loss and a positive antinuclear antibody test, she was given a trial of high dose steroids and while it significantly improved her headache, her vision did not improve. At autopsy, the left optic nerve at the level of the cavernous sinus and extending into the optic chiasm was enlarged in diameter and there was a 1.3 cm firm nodule surrounding the left optic nerve. Histologically, an abscess surrounded and involved the left optic nerve. Acute angle branching, angioinvasive fungal hyphae were identified on Grocott's methenamine silver stained sections, consistent with Aspergillus spp. No gross or microscopic evidence of systemic vasculitis or infection was identified in the body. The literature on optic nerve Aspergillosis is reviewed.

  14. Current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury using polymer scaffolds☆

    PubMed Central

    Madigan, Nicolas N.; McMahon, Siobhan; O’Brien, Timothy; Yaszemski, Michael J.; Windebank, Anthony J.

    2010-01-01

    This review highlights current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury. The concept of developing 3-dimensional polymer scaffolds for placement into a spinal cord transection model has recently been more extensively explored as a solution for restoring neurologic function after injury. Given the patient morbidity associated with respiratory compromise, the discrete tracts in the spinal cord conveying innervation for breathing represent an important and achievable therapeutic target. The aim is to derive new neuronal tissue from the surrounding, healthy cord that will be guided by the polymer implant through the injured area to make functional reconnections. A variety of naturally derived and synthetic biomaterial polymers have been developed for placement in the injured spinal cord. Axonal growth is supported by inherent properties of the selected polymer, the architecture of the scaffold, permissive microstructures such as pores, grooves or polymer fibres, and surface modifications to provide improved adherence and growth directionality. Structural support of axonal regeneration is combined with integrated polymeric and cellular delivery systems for therapeutic drugs and for neurotrophic molecules to regionalize growth of specific nerve populations. PMID:19737633

  15. Microgravity Polymers

    NASA Technical Reports Server (NTRS)

    1986-01-01

    A one-day, interactive workshop considering the effects of gravity on polymer materials science was held in Cleveland, Ohio, on May 9, 1985. Selected programmatic and technical issues were reviewed to introduce the field to workshop participants. Parallel discussions were conducted in three disciplinary working groups: polymer chemistry, polymer physics, and polymer engineering. This proceedings presents summaries of the workshop discussions and conclusions.

  16. [New treatment for peripheral nerve defects: nerve elongation].

    PubMed

    Kou, Y H; Jiang, B G

    2016-10-18

    Peripheral nerve defects are still a major challenge in clinical practice, and the most commonly used method of treatment for peripheral nerve defects is nerve transplantation, which has certain limitations and shortcomings, so new repair methods and techniques are needed. The peripheral nerve is elongated in limb lengthening surgery without injury, from which we got inspirations and proposed a new method to repair peripheral nerve defects: peripheral nerve elongation. The peripheral nerve could beelongated by a certain percent, but the physiological change and the maximum elongation range were still unknown. This study discussed the endurance, the physiological and pathological change of peripheral nerve elongation in detail, and got a lot of useful data. First, we developed peripheral nerve extender which could match the slow and even extension of peripheral nerve. Then, our animal experiment result confirmed that the peripheral nerve had better endurance for chronic elongation than that of acute elongation and cleared the extensibility of peripheral nerve and the range of repair for peripheral nerve defects. Our result also revealed the histological basis and changed the rule for pathological physiology of peripheral nerve elongation: the most important structure foundation of peripheral nerve elongation was Fontana band, which was the coiling of nerve fibers under the epineurium, so peripheral nerve could be stretched for 8.5%-10.0% without injury because of the Fontana band. We confirmed that peripheral nerve extending technology could have the same repair effect as traditional nerve transplantation through animal experiments. Finally, we compared the clinical outcomes between nerve elongation and performance of the conventional method in the repair of short-distance transection injuries in human elbows, and the post-operative follow-up results demonstrated that early neurological function recovery was better in the nerve elongation group than in the

  17. Polymerizing Pyrrole Coated Poly (l-lactic acid-co-ε-caprolactone) (PLCL) Conductive Nanofibrous Conduit Combined with Electric Stimulation for Long-Range Peripheral Nerve Regeneration

    PubMed Central

    Song, Jialin; Sun, Binbin; Liu, Shen; Chen, Wei; Zhang, Yuanzheng; Wang, Chunyang; Mo, Xiumei; Che, Junyi; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

    2016-01-01

    Electrospinning and electric stimulation (ES) are both promising methods to support neuron adhesion and guide extension of neurons for nerve regeneration. Concurrently, all studies focus on either electrospinning for conduits material or ES in vitro study to accelerate nerve regeneration; few work on the combined use of these two strategies or ES in vivo study. Therefore, this study aimed to investigate the abilities of direct current ES through electrospinning conductive polymer composites composed of polypyrrole and Poly (l-lactic acid-co-ε-caprolactone) (PPY/PLCL) in peripheral nerve regeneration. PPY/PLCL composite conduits were synthesized by polymerizing pyrrole coated electrospun PLCL scaffolds. Morphologies and chemical compositions were characterized by scanning electron microscope and attenuated total reflection fourier transform infrared (ATR-FTIR) microscope. Rat pheochromocytoma 12 (PC12) cells and dorsal root ganglia (DRG) cells cultured on PPY/PLCL scaffolds were stimulated with 100 mV/cm for 4 h per day. The median neurite length and cell viability were measured in PC-12 cells. The levels of brain-derived neurotrophic factor (BDNF), glial cell derived neurotrophic factor (GDNF) and neurotrophin-3 (NT-3) were analyzed in DRG cells. In rats, 15 mm gaps of sciatic nerves were bridged using an autograft, non-stimulated PPY/PLCL conduit and PPY/PLCL conduit stimulated with 100 mV potential, respectively. A 100 mV potential direct current ES was applied for 1 h per day at 1, 3, 5 and 7 days post-implantation. The PPY/PLCL conduits with ES showed a similar performance compared with the autograft group, and significantly better than the non-stimulated PPY/PLCL conduit group. These promising results show that the PPY/PLCL conductive conduits’ combined use with ES has great potential for peripheral nerve regeneration. PMID:27877111

  18. Polymerizing Pyrrole Coated Poly (l-lactic acid-co-ε-caprolactone) (PLCL) Conductive Nanofibrous Conduit Combined with Electric Stimulation for Long-Range Peripheral Nerve Regeneration.

    PubMed

    Song, Jialin; Sun, Binbin; Liu, Shen; Chen, Wei; Zhang, Yuanzheng; Wang, Chunyang; Mo, Xiumei; Che, Junyi; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

    2016-01-01

    Electrospinning and electric stimulation (ES) are both promising methods to support neuron adhesion and guide extension of neurons for nerve regeneration. Concurrently, all studies focus on either electrospinning for conduits material or ES in vitro study to accelerate nerve regeneration; few work on the combined use of these two strategies or ES in vivo study. Therefore, this study aimed to investigate the abilities of direct current ES through electrospinning conductive polymer composites composed of polypyrrole and Poly (l-lactic acid-co-ε-caprolactone) (PPY/PLCL) in peripheral nerve regeneration. PPY/PLCL composite conduits were synthesized by polymerizing pyrrole coated electrospun PLCL scaffolds. Morphologies and chemical compositions were characterized by scanning electron microscope and attenuated total reflection fourier transform infrared (ATR-FTIR) microscope. Rat pheochromocytoma 12 (PC12) cells and dorsal root ganglia (DRG) cells cultured on PPY/PLCL scaffolds were stimulated with 100 mV/cm for 4 h per day. The median neurite length and cell viability were measured in PC-12 cells. The levels of brain-derived neurotrophic factor (BDNF), glial cell derived neurotrophic factor (GDNF) and neurotrophin-3 (NT-3) were analyzed in DRG cells. In rats, 15 mm gaps of sciatic nerves were bridged using an autograft, non-stimulated PPY/PLCL conduit and PPY/PLCL conduit stimulated with 100 mV potential, respectively. A 100 mV potential direct current ES was applied for 1 h per day at 1, 3, 5 and 7 days post-implantation. The PPY/PLCL conduits with ES showed a similar performance compared with the autograft group, and significantly better than the non-stimulated PPY/PLCL conduit group. These promising results show that the PPY/PLCL conductive conduits' combined use with ES has great potential for peripheral nerve regeneration.

  19. Fiber-optic-based surface plasmon resonance (SPR) sensors for the detection of toxic nerve agents

    NASA Astrophysics Data System (ADS)

    Prakash, Anna M. C.; Kim, Yoon-Chang; Banerji, Soame; Masson, Jean-Francois; Booksh, Karl S.

    2004-03-01

    Analytical instruments capable of detecting nerve agents in battlefield conditions where speed, accuracy and ease of operation are a must in today's military. Fast detection and decontamination of nerve agents in very low concentrations is the primary focus of our research. The method presented here focuses on optimizing polymer stabilized sensing elements on the surface of SPR fiber-optic probes. A number of polymers & polymer supported metal complexes capable of reversibly binding to the species of interest & which have robust operation in hostile environments are incorporated with the fiber optic sensing elements. An optical technique, such as Surface Plasmon Resonance (SPR), better suited to rapid data collection without sample pretreatment is employed. The approach using polymer-based optical fibers with off-the-shelf SPR system components has been tested for the detection of Pinacolyl methylphosphonate (PMP), a simulant for nerve agent Soman. Surface initiated polymeric sensors have higher sensitivity toward detecting PMP than bulk-polymerized sensors.

  20. Influences of guide-tube and bluff-body on advanced atmospheric pressure plasma source for single-crystalline polymer nanoparticle synthesis at low temperature

    NASA Astrophysics Data System (ADS)

    Kim, Dong Ha; Park, Choon-Sang; Kim, Won Hyun; Shin, Bhum Jae; Hong, Jung Goo; Park, Tae Seon; Seo, Jeong Hyun; Tae, Heung-Sik

    2017-02-01

    The use of a guide-tube and bluff-body with an advanced atmospheric pressure plasma source is investigated for the low-temperature synthesis of single-crystalline high-density plasma polymerized pyrrole (pPPy) nano-materials on glass and flexible substrates. Three process parameters, including the position of the bluff-body, Ar gas flow rate, and remoteness of the substrate from the intense and broadened plasma, are varied and examined in detail. Plus, for an in-depth understanding of the flow structure development with the guide-tube and bluff-body, various numerical simulations are also conducted using the same geometric conditions as the experiments. As a result, depending on both the position of the bluff-body and the Ar gas flow rate, an intense and broadened plasma as a glow-like discharge was produced in a large area. The production of the glow-like discharge played a significant role in increasing the plasma energy required for full cracking of the monomers in the nucleation region. Furthermore, a remote growth condition was another critical process parameter for minimizing the etching and thermal damage during the plasma polymerization, resulting in single- and poly-crystalline pPPy nanoparticles at a low temperature with the proposed atmospheric pressure plasma jet device.

  1. Decellularisation and histological characterisation of porcine peripheral nerves

    PubMed Central

    Zilic, Leyla

    2016-01-01

    ABSTRACT Peripheral nerve injuries affect a large proportion of the global population, often causing significant morbidity and loss of function. Current treatment strategies include the use of implantable nerve guide conduits (NGC's) to direct regenerating axons between the proximal and distal ends of the nerve gap. However, NGC's are limited in their effectiveness at promoting regeneration Current NGCs are not suitable as substrates for supporting either neuronal or Schwann cell growth, as they lack an architecture similar to that of the native extracellular matrix (ECM) of the nerve. The aim of this study was to create an acellular porcine peripheral nerve using a novel decellularisation protocol, in order to eliminate the immunogenic cellular components of the tissue, while preserving the three‐dimensional histoarchitecture and ECM components. Porcine peripheral nerve (sciatic branches were decellularised using a low concentration (0.1%; w/v) sodium dodecyl sulphate in conjunction with hypotonic buffers and protease inhibitors, and then sterilised using 0.1% (v/v) peracetic acid. Quantitative and qualitative analysis revealed a ≥95% (w/w) reduction in DNA content as well as preservation of the nerve fascicles and connective tissue. Acellular nerves were shown to have retained key ECM components such as collagen, laminin and fibronectin. Slow strain rate to failure testing demonstrated the biomechanical properties of acellular nerves to be comparable to fresh controls. In conclusion, we report the production of a biocompatible, biomechanically functional acellular scaffold, which may have use in peripheral nerve repair. Biotechnol. Bioeng. 2016;113: 2041–2053. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc. PMID:26926914

  2. Advances and Future Applications of Augmented Peripheral Nerve Regeneration

    PubMed Central

    Jones, Salazar; Eisenberg, Howard M.; Jia, Xiaofeng

    2016-01-01

    Peripheral nerve injuries remain a significant source of long lasting morbidity, disability, and economic costs. Much research continues to be performed in areas related to improving the surgical outcomes of peripheral nerve repair. In this review, the physiology of peripheral nerve regeneration and the multitude of efforts to improve surgical outcomes are discussed. Improvements in tissue engineering that have allowed for the use of synthetic conduits seeded with neurotrophic factors are highlighted. Selected pre-clinical and available clinical data using cell based methods such as Schwann cell, undifferentiated, and differentiated stem cell transplantation to guide and enhance peripheral nerve regeneration are presented. The limitations that still exist in the utility of neurotrophic factors and cell-based therapies are outlined. Strategies that are most promising for translation into the clinical arena are suggested. PMID:27618010

  3. Vagus nerve stimulation and magnet use: optimizing benefits.

    PubMed

    Tatum, William O; Helmers, Sandra L

    2009-07-01

    More than 10 years ago, the vagus nerve stimulator became the first device approved by the Food and Drug Administration for use in persons with epilepsy. The vagus nerve stimulator has subsequently served to spearhead the concept of neurostimulation for seizures. Chronic intermittent electrical stimulation of the left vagus nerve is the foundation for vagus nerve stimulation, yet little is known about its capability to deliver acute, on-demand, activation of stimulation through use of a magnet. Thus far, clinical use of magnet-induced vagus nerve stimulation has not been elucidated. In an effort to help guide management, we highlight current and potential uses of acute abortive therapy with vagus nerve stimulation. We review the current evidence that is available for vagus nerve stimulator magnet use, discuss potential clinical applications that exist, offer a protocol for magnet application within the institutional setting, provide our approach to titrating the magnet parameters, and make recommendations for magnet use that support an evolving standard of care.

  4. Focused ultrasound effects on nerve action potential in vitro

    PubMed Central

    Colucci, Vincent; Strichartz, Gary; Jolesz, Ferenc; Vykhodtseva, Natalia; Hynynen, Kullervo

    2009-01-01

    Minimally invasive applications of thermal and mechanical energy to selective areas of the human anatomy have led to significant advances in treatment of and recovery from typical surgical interventions. Image-guided focused ultrasound allows energy to be deposited deep into the tissue, completely noninvasively. There has long been interest in using this focal energy delivery to block nerve conduction for pain control and local anesthesia. In this study, we have performed an in vitro study to further extend our knowledge of this potential clinical application. The sciatic nerves from the bullfrog (Rana catesbeiana) were subjected to focused ultrasound (at frequencies of 0.661MHz and 1.986MHz) and to heated Ringer’s solution. The nerve action potential was shown to decrease in the experiments and correlated with temperature elevation measured in the nerve. The action potential recovered either completely, partially, or not at all, depending on the parameters of the ultrasound exposure. The reduction of the baseline nerve temperature by circulating cooling fluid through the sonication chamber did not prevent the collapse of the nerve action potential; but higher power was required to induce the same endpoint as without cooling. These results indicate that a thermal mechanism of focused ultrasound can be used to block nerve conduction, either temporarily or permanently. PMID:19647923

  5. Masseteric-facial nerve neurorrhaphy: results of a case series.

    PubMed

    Biglioli, Federico; Colombo, Valeria; Rabbiosi, Dimitri; Tarabbia, Filippo; Giovanditto, Federica; Lozza, Alessandro; Cupello, Silvia; Mortini, Pietro

    2017-01-01

    OBJECTIVE Facial palsy is a well-known functional and esthetic problem that bothers most patients and affects their social relationships. When the time between the onset of paralysis and patient presentation is less than 18 months and the proximal stump of the injured facial nerve is not available, another nerve must be anastomosed to the facial nerve to reactivate its function. The masseteric nerve has recently gained popularity over the classic hypoglossus nerve as a new motor source because of its lower associated morbidity rate and the relative ease with which the patient can activate it. The aim of this work was to evaluate the effectiveness of masseteric-facial nerve neurorrhaphy for early facial reanimation. METHODS Thirty-four consecutive patients (21 females, 13 males) with early unilateral facial paralysis underwent masseteric-facial nerve neurorrhaphy in which an interpositional nerve graft of the great auricular or sural nerve was placed. The time between the onset of paralysis and surgery ranged from 2 to 18 months (mean 13.3 months). Electromyography revealed mimetic muscle fibrillations in all the patients. Before surgery, all patients had House-Brackmann Grade VI facial nerve dysfunction. Twelve months after the onset of postoperative facial nerve reactivation, each patient underwent a clinical examination using the modified House-Brackmann grading scale as a guide. RESULTS Overall, 91.2% of the patients experienced facial nerve function reactivation. Facial recovery began within 2-12 months (mean 6.3 months) with the restoration of facial symmetry at rest. According to the modified House-Brackmann grading scale, 5.9% of the patients had Grade I function, 61.8% Grade II, 20.6% Grade III, 2.9% Grade V, and 8.8% Grade VI. The morbidity rate was low; none of the patients could feel the loss of masseteric nerve function. There were only a few complications, including 1 case of postoperative bleeding (2.9%) and 2 local infections (5.9%), and a few

  6. Barriers of the peripheral nerve

    PubMed Central

    Peltonen, Sirkku; Alanne, Maria; Peltonen, Juha

    2013-01-01

    This review introduces the traditionally defined anatomic compartments of the peripheral nerves based on light and electron microscopic topography and then explores the cellular and the most recent molecular basis of the different barrier functions operative in peripheral nerves. We also elucidate where, and how, the homeostasis of the normal human peripheral nerve is controlled in situ and how claudin-containing tight junctions contribute to the barriers of peripheral nerve. Also, the human timeline of the development of the barriers of the peripheral nerve is depicted. Finally, potential future therapeutic modalities interfering with the barriers of the peripheral nerve are discussed. PMID:24665400

  7. Neuromuscular ultrasound of cranial nerves.

    PubMed

    Tawfik, Eman A; Walker, Francis O; Cartwright, Michael S

    2015-04-01

    Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.

  8. Topography-guided spreading and drying of 6,13-bis(triisopropylsilylethynyl)-pentacene solution on a polymer insulator for the field-effect mobility enhancement

    NASA Astrophysics Data System (ADS)

    Keum, Chang-Min; Bae, Jin-Hyuk; Kim, Min-Hoi; Park, Hea-Lim; Payne, Marcia M.; Anthony, John E.; Lee, Sin-Doo

    2013-05-01

    We report on the enhancement of the field-effect mobility of solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) by unidirectional topography (UT) of an inkjet-printed polymer insulator. The UT leads to anisotropic spreading and drying of the TIPS-pentacene droplet and enables to spontaneously develop the ordered structures during the solvent evaporation. The mobility of the UT-dictated TIPS-pentacene film (0.202 ± 0.012 cm2/Vs) is found to increase by more than a factor of two compared to that of the isotropic case (0.090 ± 0.032 cm2/Vs). The structural arrangement of the TIPS-pentacene molecules in relation to the mobility enhancement is described within an anisotropic wetting formalism. Our UT-based approach to the mobility enhancement is easily applicable to different classes of soluble organic field-effect transistors by adjusting the geometrical parameters such as the height, the width, and the periodicity of the UT of an inkjet-printed insulator.

  9. Interventional multispectral photoacoustic imaging with a clinical ultrasound probe for discriminating nerves and tendons: an ex vivo pilot study

    NASA Astrophysics Data System (ADS)

    Mari, Jean Martial; Xia, Wenfeng; West, Simeon J.; Desjardins, Adrien E.

    2015-11-01

    Accurate and efficient identification of nerves is an essential component of peripheral nerve blocks. While ultrasound (US) imaging is increasingly used as a guidance modality, it often provides insufficient contrast for identifying nerves from surrounding tissues such as tendons. Electrical nerve stimulators can be used in conjunction with US imaging for discriminating nerves from surrounding tissues, but they are insufficient to reliably prevent neural punctures, so that alternative methods are highly desirable. In this study, an interventional multispectral photoacoustic (PA) imaging system was used to directly compare the signal amplitudes and spectra acquired from nerves and tendons ex vivo, for the first time. The results indicate that the system can provide significantly higher image contrast for discriminating nerves and tendons than that provided by US imaging. As such, photoacoustic imaging could be valuable as an adjunct to US for guiding peripheral nerve blocks.

  10. Interventional multispectral photoacoustic imaging with a clinical ultrasound probe for discriminating nerves and tendons: an ex vivo pilot study.

    PubMed

    Mari, Jean Martial; Xia, Wenfeng; West, Simeon J; Desjardins, Adrien E

    2015-11-01

    Accurate and efficient identification of nerves is an essential component of peripheral nerve blocks. While ultrasound (US) imaging is increasingly used as a guidance modality, it often provides insufficient contrast for identifying nerves from surrounding tissues such as tendons. Electrical nerve stimulators can be used in conjunction with US imaging for discriminating nerves from surrounding tissues, but they are insufficient to reliably prevent neural punctures, so that alternative methods are highly desirable. In this study, an interventional multispectral photoacoustic (PA) imaging system was used to directly compare the signal amplitudes and spectra acquired from nerves and tendons ex vivo, for the first time. The results indicate that the system can provide significantly higher image contrast for discriminating nerves and tendons than that provided by US imaging. As such, photoacoustic imaging could be valuable as an adjunct to US for guiding peripheral nerve blocks.

  11. Mesenchymal stem cells in a polycaprolactone conduit promote sciatic nerve regeneration and sensory neuron survival after nerve injury.

    PubMed

    Frattini, Flávia; Lopes, Fatima Rosalina Pereira; Almeida, Fernanda Martins; Rodrigues, Rafaela Fintelman; Boldrini, Leonardo Cunha; Tomaz, Marcelo A; Baptista, Abrahão Fontes; Melo, Paulo A; Martinez, Ana Maria Blanco

    2012-10-01

    Despite the fact that the peripheral nervous system is able to regenerate after traumatic injury, the functional outcomes following damage are limited and poor. Bone marrow mesenchymal stem cells (MSCs) are multipotent cells that have been used in studies of peripheral nerve regeneration and have yielded promising results. The aim of this study was to evaluate sciatic nerve regeneration and neuronal survival in mice after nerve transection followed by MSC treatment into a polycaprolactone (PCL) nerve guide. The left sciatic nerve of C57BL/6 mice was transected and the nerve stumps were placed into a biodegradable PCL tube leaving a 3-mm gap between them; the tube was filled with MSCs obtained from GFP+ animals (MSC-treated group) or with a culture medium (Dulbecco's modified Eagle's medium group). Motor function was analyzed according to the sciatic functional index (SFI). After 6 weeks, animals were euthanized, and the regenerated sciatic nerve, the dorsal root ganglion (DRG), the spinal cord, and the gastrocnemius muscle were collected and processed for light and electron microscopy. A quantitative analysis of regenerated nerves showed a significant increase in the number of myelinated fibers in the group that received, within the nerve guide, stem cells. The number of neurons in the DRG was significantly higher in the MSC-treated group, while there was no difference in the number of motor neurons in the spinal cord. We also found higher values of trophic factors expression in MSC-treated groups, especially a nerve growth factor. The SFI revealed a significant improvement in the MSC-treated group. The gastrocnemius muscle showed an increase in weight and in the levels of creatine phosphokinase enzyme, suggesting an improvement of reinnervation and activity in animals that received MSCs. Immunohistochemistry documented that some GFP+ -transplanted cells assumed a Schwann-cell-like phenotype, as evidenced by their expression of the S-100 protein, a Schwann cell

  12. Genes and nerves.

    PubMed

    Dieu, Tam; Johnstone, Bruce R; Newgreen, Don F

    2005-04-01

    The unpredictability of a brachial plexus graft, a median nerve repair, or a facial-nerve reconstruction is well known. No matter how precise the technical skills, a perfect recovery from a peripheral-nerve lesion is elusive. To resolve this problem, understanding of the normal development of the peripheral nervous system is needed. Presently, the development of the innervation in the upper limb is complex and not fully understood. However, many of the genes involved in this process are now known, and the link between anatomy and genetics is becoming clearer. This short review aims to acquaint the clinical surgeon with some of the main genes. The principal steps in the establishment of neural circuits will be summarized, in particular, the specification and development of neurons and glia, the pathfinding of cells and axons towards their target, and the downstream molecules that control the circuitry of these neurons.

  13. [Lumbosacral nerve bowstring disease].

    PubMed

    Shi, J G; Xu, X M; Sun, J C; Wang, Y; Guo, Y F; Yang, H S; Kong, Q J; Yang, Y; Shi, G D; Yuan, W; Jia, L S

    2017-03-21

    Objective: To define a novel disease-lumbosacral nerve bowstring disease, and propose the diagnostic criteria, while capsule surgery was performed and evaluated in the preliminary study. Methods: From June 2016 to December 2016, a total of 30 patients (22 male and 8 female; mean age of 55.1±9.7 years) with lumbosacral nerve bowstring disease were included in Department of Spine Surgery, Changzheng Hospital, the Second Military Medical University.Lumbosacral nerve bowstring disease was defined as axial hypertension of nerve root and spinal cord caused by congenital anomalies, which could be accompanied by other lesions as lumbar disc herniation, spinal cord stenosis or spondylolisthesis, or aggravated by iatrogenic lesions, resulting in neurological symptoms.This phenomenon is similar to a stretched string, the higher tension on each end the louder sound.Meanwhile, the shape of lumbosacral spine looks like a bow, thus, the disease is nominated as lumbosacral nerve bowstring disease.All the patients underwent capsule surgery and filled out Owestry disability index (ODI) and Tempa scale for kinesiophobia (TSK) before and after surgery. Results: The mean surgery time was (155±36) min, (4.3±0.4) segments were performed surgery.The pre-operative VAS, TSK and ODI scores were (7.6±0.8), (52.0±10.3) and (68.4±12.7), respectively.The post-operative VAS, TSK and ODI scores were (3.3±0.4), ( 24.6±5.2) and (32.1±7.4)(P<0.05, respectively), respectively. Conclusion: The definition and diagnostic criteria of lumbosacral nerve bowstring disease was proposed.Capsule surgery was an effective strategy with most patients acquired excellent outcomes as symptoms relieved and quality of life improved.

  14. Design of barrier coatings on kink-resistant peripheral nerve conduits

    PubMed Central

    Clements, Basak Acan; Bushman, Jared; Murthy, N Sanjeeva; Ezra, Mindy; Pastore, Christopher M; Kohn, Joachim

    2016-01-01

    Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1) electrospinning a layer of polymer fibers onto the surface of the conduit and (2) coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery. PMID:26977288

  15. Skin-derived precursors as a source of progenitors for cutaneous nerve regeneration.

    PubMed

    Chen, Zhiguo; Pradhan, Sanjay; Liu, Chiachi; Le, Lu Q

    2012-10-01

    Peripheral nerves have the potential to regenerate axons and reinnervate end organs. Chronic denervation and disturbed nerve regeneration are thought to contribute to peripheral neuropathy, pain, and pruritus in the skin. The capacity of denervated distal nerves to support axonal regeneration requires proliferation by Schwann cells, which guide regenerating axons to their denervated targets. However, adult peripheral nerve Schwann cells do not retain a growth-permissive phenotype, as is required to produce new glia. Therefore, it is believed that following injury, mature Schwann cells dedifferentiate to a progenitor/stem cell phenotype to promote axonal regrowth. In this study, we show that skin-derived precursors (SKPs), a recently identified neural crest-related stem cell population in the dermis of skin, are an alternative source of progenitors for cutaneous nerve regeneration. Using in vivo and in vitro three-dimensional cutaneous nerve regeneration models, we show that the SKPs are neurotropic toward injured nerves and that they have a full capacity to differentiate into Schwann cells and promote axon regeneration. The identification of SKPs as a physiologic source of progenitors for cutaneous nerve regeneration in the skin, where SKPs physiologically reside, has important implications for understanding early cellular events in peripheral nerve regeneration. It also provides fertile ground for the elucidation of intrinsic and extrinsic factors within the nerve microenvironment that likely play essential roles in cutaneous nerve homeostasis.

  16. Skin-derived precursors as a source of progenitors for cutaneous nerve regeneration

    PubMed Central

    Chen, Zhiguo; Pradhan, Sanjay; Liu, Chiachi; Le, Lu Q.

    2012-01-01

    Peripheral nerves have the potential to regenerate axons and reinnervate end organs. Chronic denervation and disturbed nerve regeneration are thought to contribute to peripheral neuropathy, pain and pruritus in the skin. The capacity of denervated distal nerves to support axonal regeneration requires proliferation by Schwann cells, which guide regenerating axons to their denervated targets. However, adult peripheral nerve Schwann cells do not retain a growth-permissive phenotype, as is required to produce new glia. Therefore, it is believed that following injury, mature Schwann cells de-differentiate to a progenitor/stem cell phenotype to promote axonal re-growth. In this study, we show that Skin-derived precursors (SKPs), a recently identified neural-crest related stem cell population in the dermis of skin, are an alternative source of progenitors for cutaneous nerve regeneration. Using in vivo and in vitro 3-D cutaneous nerve regeneration models, we show that the SKPs are neurotropic toward injured nerves and that they have a full capacity to differentiate into Schwann cells and promote axon regeneration. The identification of SKPs as a physiologic source of progenitors for cutaneous nerve regeneration in the skin, where SKPs physiologically reside, has important implications for understanding early cellular events in peripheral nerve regeneration. It also provides fertile ground for the elucidation of intrinsic and extrinsic factors within the nerve microenvironment that likely play essential roles in cutaneous nerve homeostasis. PMID:22851518

  17. Nerve Transfers in Tetraplegia.

    PubMed

    Fox, Ida K

    2016-05-01

    Hand and upper extremity function is instrumental to basic activities of daily living and level of independence in cervical spinal cord injury (SCI). Nerve transfer surgery is a novel and alternate approach for restoring function in SCI. This article discusses the biologic basis of nerve transfers in SCI, patient evaluation, management, and surgical approaches. Although the application of this technique is not new; recent case reports and case series in the literature have increased interest in this field. The challenges are to improve function, achieve maximal gains in function, avoid complications, and to primum non nocere.

  18. Data Mining as a Guide for the Construction of Cross-Linked Nanoparticles with Low Immunotoxicity via Control of Polymer Chemistry and Supramolecular Assembly.

    PubMed

    Elsabahy, Mahmoud; Wooley, Karen L

    2015-06-16

    The potential immunotoxicity of nanoparticles that are currently being approved, in different phases of clinical trials, or undergoing rigorous in vitro and in vivo characterizations in several laboratories has recently raised special attention. Products with no apparent in vitro or in vivo toxicity may still trigger various components of the immune system unintentionally and lead to serious adverse reactions. Cytokines are one of the useful biomarkers for predicting the effect of biotherapeutics on modulation of the immune system and for screening the immunotoxicity of nanoparticles both in vitro and in vivo, and they were recently found to partially predict the in vivo pharmacokinetics and biodistribution of nanomaterials. Control of polymer chemistry and supramolecular assembly provides a great opportunity for the construction of biocompatible nanoparticles for biomedical clinical applications. However, the sources of data collected regarding immunotoxicities of nanomaterials are diverse, and experiments are usually conducted using different assays under specific conditions. As a result, making direct comparisons nearly impossible, and thus, tailoring the properties of nanomaterials on the basis of the available data is challenging. In this Account, the effects of chemical structure, cross-linking, degradability, morphology, concentration, and surface chemistry on the immunotoxicity of an expansive array of polymeric nanomaterials will be highlighted, with a focus on assays conducted using the same in vitro and in vivo models and experimental conditions. Furthermore, numerical descriptive values have been utilized uniquely to stand for induction of cytokines by nanoparticles. This treatment of available data provides a simple way to compare the immunotoxicities of various nanomaterials, and the values were found to correlate well with published data. On the basis of the polymeric systems investigated in this study, valuable information has been collected that

  19. Overview of the Cranial Nerves

    MedlinePlus

    ... and toxins. Some cranial nerve disorders interfere with eye movement. Eye movement is controlled by 3 pairs of muscles. These ... be able to move their eyes normally. How eye movement is affected depends on which nerve is affected. ...

  20. Nerve Injuries of the Upper Extremity

    MedlinePlus

    ... of individual nerve fibers and surrounding outer sheath (“insulation”) Figure 2: Nerve repair with realignment of bundles © ... of individual nerve fibers and surrounding outer sheath insulation Figure 2 - Nerve repair with realignment of bundles ...

  1. Polymer concepts in tissue engineering.

    PubMed

    Peter, S J; Miller, M J; Yasko, A W; Yaszemski, M J; Mikos, A G

    1998-01-01

    Traumatic injuries, cancer treatment, and congenital abnormalities are often associated with abnormal bone shape or segmental bone loss. Restoration of normal structure and function in these cases requires replacement of the missing bone that may be accomplished by surgical transfer of natural tissue from an uninjured location elsewhere in the body. However, this procedure is limited by availability, adequate blood supply, and secondary deformities at the donor site. One strategy to overcome these problems is to develop living tissue substitutes based on synthetic biodegradable polymers. Three methods of bone regeneration using biodegradable polymers are being studied in our laboratory: tissue induction, cell transplantation, and fabrication of vascularized bone flaps. Injectable polymers are used for filling skeletal defects and guiding bone tissue growth. Their main advantage is minimizing the surgical intervention or the severity of the surgery. Polymer-cell constructs also hold great promise in the field of tissue engineering. They provide a scaffold on which cells grow and organize themselves. As the cells begin to secrete their own extracellular matrix, the polymer degrades and is eventually eliminated from the body, resulting in completely natural tissue replacement. Bone flaps can be fabricated ectopically into precise shapes and sizes. With an attached vascular supply, these flaps can be transferred into areas deficient in vascularity. This article discusses polymer concepts regarding bone tissue engineering and reviews recent advances of our laboratory on guided bone regeneration using biodegradable polymer scaffolds.

  2. Optic nerve hypoplasia in children.

    PubMed Central

    Zeki, S. M.; Dutton, G. N.

    1990-01-01

    Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving. Images PMID:2191713

  3. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy

    NASA Astrophysics Data System (ADS)

    Yan, Sijing; Lu, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-08-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic.

  4. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy

    PubMed Central

    Yan, Sijing; LU, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-01-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic. PMID:27535093

  5. Orientated Guidance of Peripheral Nerve Regeneration Using Conduits with a Microtube Array Sheet (MTAS).

    PubMed

    Wang, Yueming; Wang, Wenjin; Wo, Yan; Gui, Ting; Zhu, Hao; Mo, Xiumei; Chen, Chien-Chung; Li, Qingfeng; Ding, Wenlong

    2015-04-29

    Material surface topography has been shown to affect the biological behavior of cells in vitro; however, the in vivo effect on peripheral nerve regeneration has not been explored. Here, we studied the potential of a microtube array sheet (MTAS) with a unique longitudinal surface topography to promote peripheral nerve regeneration efficiency, both in vivo and in vitro. Schwann cells, spinal cord motor neurons, and dorsal root ganglion neurons were seeded on the MTAS to study the effect of the construct on the biological properties and behaviors of neural cells. The MTAS guided the oriented migration of Schwann cells without affecting other critical biological properties, such as proliferation and neurotrophin expression. In addition, the MTAS guided the directed extension of neurites from both types of neurons. Next, we tested the capability of the MTAS to facilitate peripheral nerve regeneration by bridging a 10 mm sciatic nerve defect in rats with a nerve conduit equipped with an MTAS lining. The MTAS significantly promoted peripheral nerve regeneration, as suggested by the greater fiber caliber in the midconduit and the greater abundance of fibers in nerve segment distal to the conduit. Moreover, scanning electron microscopy (SEM) analysis suggested the orientated guidance of nerve regeneration by the MTAS, as indicated by the smaller eccentricity of the nerve fibers and the concordant arrangement of the collagen fiber in both the fibers and the matrix in the MTAS group. Our results collectively suggest that the conduits with the MTAS developed in this study have significant potential for facilitating peripheral nerve regeneration by modifying critical biological behaviors and guiding orientated nerve growth.

  6. Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Harrison, J. S.; Ounaies, Z.; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    The purpose of this review is to detail the current theoretical understanding of the origin of piezoelectric and ferroelectric phenomena in polymers; to present the state-of-the-art in piezoelectric polymers and emerging material systems that exhibit promising properties; and to discuss key characterization methods, fundamental modeling approaches, and applications of piezoelectric polymers. Piezoelectric polymers have been known to exist for more than forty years, but in recent years they have gained notoriety as a valuable class of smart materials.

  7. Active Polymer Microfiber with Controlled Polarization Sensitivity

    PubMed Central

    Xia, Hongyan; Wang, Ruxue; Liu, Yingying; Cheng, Junjie; Zou, Gang; Zhang, Qijin; Zhang, Douguo; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

    2016-01-01

    Controlled Polarization Sensitivity of an active polymer microfiber has been proposed and realized with the electrospun method. The fluorescence intensity guiding through this active polymer microfiber shows high sensitivity to the polarization state of the excitation light. What is more, the fluorescence out-coupled from tip of the microfiber can be of designed polarization state. Principle of these phenomena lies on the ordered and controlled orientation of the polydiacetylene (PDA) main chains inside polymer microfiber. PMID:27099828

  8. Femoral nerve dysfunction

    MedlinePlus

    ... Read More Abscess Diabetes Mononeuropathy Multiple mononeuropathy Myelin Peripheral neuropathy Polyarteritis nodosa Systemic Tumor Review Date 1/5/ ... Related MedlinePlus Health Topics Leg Injuries and Disorders Peripheral Nerve Disorders Browse the Encyclopedia A.D.A.M., Inc. ...

  9. Nerves and Tissue Repair.

    DTIC Science & Technology

    1994-07-01

    axolotl limbs are transected the concentration of transferrin in the distal limb tissue declines rapidly and limb regeneration stops. These results...transferrin binding and expression of the transferrin gene in cells of axolotl peripheral nerve indicate that both uptake and synthesis of this factor occur

  10. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  11. Sciatic nerve repair with tissue engineered nerve: Olfactory ensheathing cells seeded poly(lactic-co-glygolic acid) conduit in an animal model

    PubMed Central

    Tan, C W; Ng, M H; Ohnmar, H; Lokanathan, Y; Nur-Hidayah, H; Roohi, S A; Ruszymah, BHI; Nor-Hazla, M H; Shalimar, A; Naicker, A S

    2013-01-01

    Background and Aim: Synthetic nerve conduits have been sought for repair of nerve defects as the autologous nerve grafts causes donor site morbidity and possess other drawbacks. Many strategies have been investigated to improve nerve regeneration through synthetic nerve guided conduits. Olfactory ensheathing cells (OECs) that share both Schwann cell and astrocytic characteristics have been shown to promote axonal regeneration after transplantation. The present study was driven by the hypothesis that tissue-engineered poly(lactic-co-glycolic acid) (PLGA) seeded with OECs would improve peripheral nerve regeneration in a long sciatic nerve defect. Materials and Methods: Sciatic nerve gap of 15 mm was created in six adult female Sprague-Dawley rats and implanted with PLGA seeded with OECs. The nerve regeneration was assessed electrophysiologically at 2, 4 and 6 weeks following implantation. Histopathological examination, scanning electron microscopic (SEM) examination and immunohistochemical analysis were performed at the end of the study. Results: Nerve conduction studies revealed a significant improvement of nerve conduction velocities whereby the mean nerve conduction velocity increases from 4.2 ΁ 0.4 m/s at week 2 to 27.3 ΁ 5.7 m/s at week 6 post-implantation (P < 0.0001). Histological analysis revealed presence of spindle-shaped cells. Immunohistochemical analysis further demonstrated the expression of S100 protein in both cell nucleus and the cytoplasm in these cells, hence confirming their Schwann-cell-like property. Under SEM, these cells were found to be actively secreting extracellular matrix. Conclusion: Tissue-engineered PLGA conduit seeded with OECs provided a permissive environment to facilitate nerve regeneration in a small animal model. PMID:24379458

  12. Cellulose/soy protein composite-based nerve guidance conduits with designed microstructure for peripheral nerve regeneration

    NASA Astrophysics Data System (ADS)

    Gan, Li; Zhao, Lei; Zhao, Yanteng; Li, Ke; Tong, Zan; Yi, Li; Wang, Xiong; Li, Yinping; Tian, Weiqun; He, Xiaohua; Zhao, Min; Li, Yan; Chen, Yun

    2016-10-01

    Objective. The objective of this work was to develop nerve guidance conduits from natural polymers, cellulose and soy protein isolate (SPI), by evaluating the effects of cellulose/SPI film-based conduit (CSFC) and cellulose/SPI sponge-based conduit (CSSC) on regeneration of nerve defects in rats. Approach. CSFC and CSSC with the same chemical components were fabricated from cellulose and SPI. Effects of CSSC and CSFC on regeneration of the defective nerve were comparatively investigated in rats with a 10 mm long gap in sciatic nerve. The outcomes of peripheral nerve repair were evaluated by a combination of electrophysiological assessment, Fluoro-Gold retrograde tracing, double NF200/S100 immunofluorescence analysis, toluidine blue staining, and electron microscopy. The probable molecular mechanism was investigated using quantitative real-time PCR (qPCR) analysis. Main results. Compared with CSFC, CSSC had 2.69 times higher porosity and 5.07 times higher water absorption, thus ensuring much higher permeability. The nerve defects were successfully bridged and repaired by CSSC and CSFC. Three months after surgery, the CSSC group had a higher compound muscle action potential amplitude ratio, a higher percentage of positive NF200 and S100 staining, and a higher axon diameter and myelin sheath thickness than the CSFC group, showing the repair efficiency of CSSC was higher than that of CSFC. qPCR analysis indicated the mRNA levels of nerve growth factor, IL-10, IL-6, and growth-associated protein 43 (GAP-43) were higher in the CSSC group. This also indicated that there was better nerve repair with CSSC due to the higher porosity and permeability of CSSC providing a more favourable microenvironment for nerve regeneration than CSFC. Significance. A promising nerve guidance conduit was developed from cellulose/SPI sponge that showed potential for application in the repair of nerve defect. This work also suggests that nerve guidance conduits with better repair efficiency

  13. Dorsal clitoral nerve injury following transobturator midurethral sling

    PubMed Central

    Moss, Chailee F; Damitz, Lynn A; Gracely, Richard H; Mintz, Alice C; Zolnoun, Denniz A; Dellon, A Lee

    2016-01-01

    Introduction Transobturator slings can be successfully used to treat stress urinary incontinence and improve quality of life through a minimally invasive vaginal approach. Persistent postoperative pain can occur and pose diagnostic and therapeutic dilemmas. Following a sling procedure, a patient complained of pinching clitoral and perineal pain. Her symptoms of localized clitoral pinching and pain became generalized over the ensuing years, eventually encompassing the entire left vulvovaginal region. Aim The aim of this study was to highlight the clinical utility of conventional pain management techniques used for the evaluation and management of patients with postoperative pain following pelvic surgery. Methods We described a prototypical patient with persistent pain in and around the clitoral region complicating the clinical course of an otherwise successful sling procedure. We specifically discussed the utility of bedside sensory assessment techniques and selective nerve blocks in the evaluation and management of this prototypical patient. Results Neurosensory assessments and a selective nerve block enabled us to trace the source of the patient’s pain to nerve entrapment along the dorsal nerve of the clitoris. We then utilized a nerve stimulator-guided hydrodissection technique to release the scar contracture Conclusion This case demonstrates that the dorsal nerve of the clitoris is vulnerable to injury directly and/or indirectly. Assimilation of a time-honored pain management construct for the evaluation and management of patients’ pain may improve outcomes while obviating the need for invasive surgery. PMID:27729812

  14. Scaffolds from block polyurethanes based on poly(ɛ-caprolactone) (PCL) and poly(ethylene glycol) (PEG) for peripheral nerve regeneration.

    PubMed

    Niu, Yuqing; Chen, Kevin C; He, Tao; Yu, Wenying; Huang, Shuiwen; Xu, Kaitian

    2014-05-01

    Nerve guide scaffolds from block polyurethanes without any additional growth factors or protein were prepared using a particle leaching method. The scaffolds of block polyurethanes (abbreviated as PUCL-ran-EG) based on poly(ɛ-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) possess highly surface-area porous for cell attachment, and can provide biochemical and topographic cues to enhance tissue regeneration. The nerve guide scaffolds have pore size 1-5 μm and porosity 88%. Mechanical tests showed that the polyurethane nerve guide scaffolds have maximum loads of 4.98 ± 0.35 N and maximum stresses of 6.372 ± 0.5 MPa. The histocompatibility efficacy of these nerve guide scaffolds was tested in a rat model for peripheral nerve injury treatment. Four types of guides including PUCL-ran-EG scaffolds, autograft, PCL scaffolds and silicone tubes were compared in the rat model. After 14 weeks, bridging of a 10 mm defect gap by the regenerated nerve was observed in all rats. The nerve regeneration was systematically characterized by sciatic function index (SFI), histological assessment including HE staining, immunohistochemistry, ammonia silver staining, Masson's trichrome staining and TEM observation. Results revealed that polyurethane nerve guide scaffolds exhibit much better regeneration behavior than PCL, silicone tube groups and comparable to autograft. Electrophysiological recovery was also seen in 36%, 76%, and 87% of rats in the PCL, PUCL-ran-EG, and autograft groups respectively, whilst 29.8% was observed in the silicone tube groups. Biodegradation in vitro and in vivo show proper degradation of the PUCL-ran-EG nerve guide scaffolds. This study has demonstrated that without further modification, plain PUCL-ran-EG nerve guide scaffolds can help peripheral nerve regeneration excellently.

  15. Nerve root replantation.

    PubMed

    Carlstedt, Thomas

    2009-01-01

    Traumatic avulsion of nerve roots from the spinal cord is a devastating event that usually occurs in the brachial plexus of young adults following motor vehicle or sports accidents or in newborn children during difficult childbirth. A strategy to restore motor function in the affected arm by reimplanting into the spinal cord the avulsed ventral roots or autologous nerve grafts connected distally to the avulsed roots has been developed. Surgical outcome is good and useful recovery in shoulder and proximal arm muscles occurs. Pain is alleviated with motor recovery but sensory improvement is poor when only motor conduits have been reconstructed. In experimental studies, restoration of sensory connections with general improvement in the outcome from this surgery is pursued.

  16. Suprascapular nerve block in chronic shoulder pain: are the radiologists better?

    PubMed Central

    Shanahan, E; Smith, M; Wetherall, M; Lott, C; Slavotinek, J; FitzGerald, O; Ahern, M

    2004-01-01

    Background: Suprascapular nerve block is a safe and effective treatment for chronic shoulder pain in arthritis, which can be performed either by direct imaging (CT guided) or in the clinic using anatomical landmarks to determine needle placement. Objective: To compare a CT guided versus an anatomical landmark approach in a randomised, single blind trial examining the efficacy of suprascapular nerve block for shoulder pain in patients with degenerative joint/rotator cuff disease. Methods: 67 patients with chronic shoulder pain from degenerative disease participated in the trial. 77 shoulders were randomised. The group randomised to receive the block through the anatomical landmark approach received a single suprascapular nerve block. Those in the CT guided group received an injection of methylprednisolone acetate and a smaller volume of bupivacaine around the suprascapular nerve. The patients were followed up for 12 weeks by a "blinded" observer and reviewed at weeks 1, 4, and 12 after the injection. Results: Significant improvements were seen in all pain scores and disability in the shoulders receiving both types of nerve block, with no significant differences in the improvement in pain and disability between the two approaches at any time. Improvements in pain and disability scores were clinically and statistically significant. No significant adverse effects occurred in either group. Patient satisfaction scores for pain relief using either approach were high. Conclusion: The CT guided control and landmark approaches to performing suprascapular nerve blocks result in similar significant and prolonged pain and disability reductions; both approaches are safe. PMID:15308514

  17. Conjugated poly(fluorene-quinoxaline) for fluorescence imaging and chemical detection of nerve agents with its paper-based strip.

    PubMed

    Jo, Seonyoung; Kim, Daigeun; Son, Sang-Ho; Kim, Yongkyun; Lee, Taek Seung

    2014-01-22

    Conjugated polymer of poly(fluorene-co-quinoxaline) was synthesized via Suzuki coupling polymerization. The emission color of the polymer can be tuned depending on the concentration of the polymer in solution. A low-energy bandgap is observed both in the concentrated solution and in the solid state, caused by aggregation of the polymer chains, resulting in long wavelength emission from the quinoxaline moiety, while short wavelength emission can be seen in diluted, well-dissolved solution. The presence of quinoxaline units enables us to demonstrate fluorescence switching and imaging. Paper-based strips containing the polymer are prepared via simple immersion of filter paper in the polymer solution for practical use in the detection of nerve agents. The emission of the paper-based strip is quenched upon exposure to diethyl chlorophosphate (DCP), a nerve agent simulant, and the initial emission intensity can be almost restored by treatment with aqueous sodium hydroxide solution, making a possible reversible paper-based sensor.

  18. Microvascular Cranial Nerve Palsy

    MedlinePlus

    ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  19. Polylactic-co-glycolic acid microspheres containing three neurotrophic factors promote sciatic nerve repair after injury.

    PubMed

    Zhao, Qun; Li, Zhi-Yue; Zhang, Ze-Peng; Mo, Zhou-Yun; Chen, Shi-Jie; Xiang, Si-Yu; Zhang, Qing-Shan; Xue, Min

    2015-09-01

    A variety of neurotrophic factors have been shown to repair the damaged peripheral nerve. However, in clinical practice, nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor are all peptides or proteins that may be rapidly deactivated at the focal injury site; their local effective concentration time following a single medication cannot meet the required time for spinal axons to regenerate and cross the glial scar. In this study, we produced polymer sustained-release microspheres based on the polylactic-co-glycolic acid copolymer; the microspheres at 300-μm diameter contained nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor. Six microspheres were longitudinally implanted into the sciatic nerve at the anastomosis site, serving as the experimental group; while the sciatic nerve in the control group was subjected to the end-to-end anastomosis using 10/0 suture thread. At 6 weeks after implantation, the lower limb activity, weight of triceps surae muscle, sciatic nerve conduction velocity and the maximum amplitude were obviously better in the experimental group than in the control group. Compared with the control group, more regenerating nerve fibers were observed and distributed in a dense and ordered manner with thicker myelin sheaths in the experimental group. More angiogenesis was also visible. Experimental findings indicate that polylactic-co-glycolic acid composite microspheres containing nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor can promote the restoration of sciatic nerve in rats after injury.

  20. Polylactic-co-glycolic acid microspheres containing three neurotrophic factors promote sciatic nerve repair after injury

    PubMed Central

    Zhao, Qun; Li, Zhi-yue; Zhang, Ze-peng; Mo, Zhou-yun; Chen, Shi-jie; Xiang, Si-yu; Zhang, Qing-shan; Xue, Min

    2015-01-01

    A variety of neurotrophic factors have been shown to repair the damaged peripheral nerve. However, in clinical practice, nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor are all peptides or proteins that may be rapidly deactivated at the focal injury site; their local effective concentration time following a single medication cannot meet the required time for spinal axons to regenerate and cross the glial scar. In this study, we produced polymer sustained-release microspheres based on the polylactic-co-glycolic acid copolymer; the microspheres at 300-μm diameter contained nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor. Six microspheres were longitudinally implanted into the sciatic nerve at the anastomosis site, serving as the experimental group; while the sciatic nerve in the control group was subjected to the end-to-end anastomosis using 10/0 suture thread. At 6 weeks after implantation, the lower limb activity, weight of triceps surae muscle, sciatic nerve conduction velocity and the maximum amplitude were obviously better in the experimental group than in the control group. Compared with the control group, more regenerating nerve fibers were observed and distributed in a dense and ordered manner with thicker myelin sheaths in the experimental group. More angiogenesis was also visible. Experimental findings indicate that polylactic-co-glycolic acid composite microspheres containing nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor can promote the restoration of sciatic nerve in rats after injury. PMID:26604912

  1. Nanostructured Guidance for Peripheral Nerve Injuries: A Review with a Perspective in the Oral and Maxillofacial Area

    PubMed Central

    Sivolella, Stefano; Brunello, Giulia; Ferrarese, Nadia; Puppa, Alessandro Della; D’Avella, Domenico; Bressan, Eriberto; Zavan, Barbara

    2014-01-01

    Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments. PMID:24562333

  2. Peripheral Nerve Injury: Stem Cell Therapy and Peripheral Nerve Transfer

    PubMed Central

    Sullivan, Robert; Dailey, Travis; Duncan, Kelsey; Abel, Naomi; Borlongan, Cesario V.

    2016-01-01

    Peripheral nerve injury can lead to great morbidity in those afflicted, ranging from sensory loss, motor loss, chronic pain, or a combination of deficits. Over time, research has investigated neuronal molecular mechanisms implicated in nerve damage, classified nerve injury, and developed surgical techniques for treatment. Despite these advancements, full functional recovery remains less than ideal. In this review, we discuss historical aspects of peripheral nerve injury and introduce nerve transfer as a therapeutic option, as well as an adjunct therapy to transplantation of Schwann cells and their stem cell derivatives for repair of the damaged nerve. This review furthermore, will provide an elaborated discussion on the sources of Schwann cells, including sites to harvest their progenitor and stem cell lines. This reflects the accessibility to an additional, concurrent treatment approach with nerve transfers that, predicated on related research, may increase the efficacy of the current approach. We then discuss the experimental and clinical investigations of both Schwann cells and nerve transfer that are underway. Lastly, we provide the necessary consideration that these two lines of therapeutic approaches should not be exclusive, but conversely, should be pursued as a combined modality given their mutual role in peripheral nerve regeneration. PMID:27983642

  3. Nerve regeneration in nerve grafts conditioned by vibration exposure.

    PubMed

    Bergman, S; Widerberg, A; Danielsen, N; Lundborg, G; Dahlin, L B

    1995-01-01

    Regeneration distances were studied in nerves from vibration-exposed limbs. One hind limb of anaesthetized rats was attached to a vibration exciter and exposed to vibration (80 Hz/32 m/s2) for 5 h/day for 2 or 5 days. Seven days after the latest vibration period a 10-mm long nerve graft was taken from the vibrated sciatic nerve and sutured into a corresponding defect in the con-tralateral sciatic nerve and vice versa, thereby creating two different models within the same animal: (i) regeneration from a freshly transected unvibrated nerve into a vibrated graft and (ii) regeneration from a vibrated nerve into a fresh nerve graft (vibrated recipient side). Four, 6 or 8 days postoperatively (p.o.) the distances achieved by the regenerating axons were determined using the pinch reflex test. Two days of vibration did not influence the regeneration, but 5 days of vibration reduced the initial delay period and a slight reduction of regeneration rate was observed. After 5 days of vibration an increased regeneration distance was observed in both models at day 4 p.o. and at day 6 p.o. in vibrated grafts. This study demonstrates that vibration can condition peripheral nerves and this may be caused by local changes in the peripheral nerve trunk and in the neuron itself.

  4. Star Polymers.

    PubMed

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  5. Polymer Chemistry

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  6. Neuromuscular Ultrasound of Cranial Nerves

    PubMed Central

    Tawfik, Eman A.; Cartwright, Michael S.

    2015-01-01

    Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed. PMID:25851889

  7. Nerve Cross-Bridging to Enhance Nerve Regeneration in a Rat Model of Delayed Nerve Repair

    PubMed Central

    2015-01-01

    There are currently no available options to promote nerve regeneration through chronically denervated distal nerve stumps. Here we used a rat model of delayed nerve repair asking of prior insertion of side-to-side cross-bridges between a donor tibial (TIB) nerve and a recipient denervated common peroneal (CP) nerve stump ameliorates poor nerve regeneration. First, numbers of retrogradely-labelled TIB neurons that grew axons into the nerve stump within three months, increased with the size of the perineurial windows opened in the TIB and CP nerves. Equal numbers of donor TIB axons regenerated into CP stumps either side of the cross-bridges, not being affected by target neurotrophic effects, or by removing the perineurium to insert 5-9 cross-bridges. Second, CP nerve stumps were coapted three months after inserting 0-9 cross-bridges and the number of 1) CP neurons that regenerated their axons within three months or 2) CP motor nerves that reinnervated the extensor digitorum longus (EDL) muscle within five months was determined by counting and motor unit number estimation (MUNE), respectively. We found that three but not more cross-bridges promoted the regeneration of axons and reinnervation of EDL muscle by all the CP motoneurons as compared to only 33% regenerating their axons when no cross-bridges were inserted. The same 3-fold increase in sensory nerve regeneration was found. In conclusion, side-to-side cross-bridges ameliorate poor regeneration after delayed nerve repair possibly by sustaining the growth-permissive state of denervated nerve stumps. Such autografts may be used in human repair surgery to improve outcomes after unavoidable delays. PMID:26016986

  8. Nanohelices from planar polymer self-assembled in carbon nanotubes.

    PubMed

    Fu, Hongjin; Xu, Shuqiong; Li, Yunfang

    2016-07-21

    The polymer possessing with planar structure can be activated and guided to encapsulate the inner space of SWNT and form a helix through van der Waals interaction and the π-π stacking effect between the polymer and the inner surface of SWNT. The SWNT size, the nanostructure and flexibility of polymer chain are all determine the final structures. The basic interaction between the polymer and the nanotubes is investigated, and the condition and mechanism of the helix-forming are explained particularly. Hybrid polymers improve the ability of the helix formation. This study provides scientific basis for fabricating helical polymers encapsulated in SWNTs and eventually on their applications in various areas.

  9. Nanohelices from planar polymer self-assembled in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Fu, Hongjin; Xu, Shuqiong; Li, Yunfang

    2016-07-01

    The polymer possessing with planar structure can be activated and guided to encapsulate the inner space of SWNT and form a helix through van der Waals interaction and the π-π stacking effect between the polymer and the inner surface of SWNT. The SWNT size, the nanostructure and flexibility of polymer chain are all determine the final structures. The basic interaction between the polymer and the nanotubes is investigated, and the condition and mechanism of the helix-forming are explained particularly. Hybrid polymers improve the ability of the helix formation. This study provides scientific basis for fabricating helical polymers encapsulated in SWNTs and eventually on their applications in various areas.

  10. Neutron guide

    DOEpatents

    Greene, Geoffrey L.

    1999-01-01

    A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

  11. Nerve blocks for chronic pain.

    PubMed

    Hayek, Salim M; Shah, Atit

    2014-10-01

    Nerve blocks are often performed as therapeutic or palliative interventions for pain relief. However, they are often performed for diagnostic or prognostic purposes. When considering nerve blocks for chronic pain, clinicians must always consider the indications, risks, benefits, and proper technique. Nerve blocks encompass a wide variety of interventional procedures. The most common nerve blocks for chronic pain and that may be applicable to the neurosurgical patient population are reviewed in this article. This article is an introduction and brief synopsis of the different available blocks that can be offered to a patient.

  12. Nerves on magnetic resonance imaging.

    PubMed Central

    Collins, J. D.; Shaver, M. L.; Batra, P.; Brown, K.

    1989-01-01

    Nerves are often visualized on magnetic resonance imaging (MRI) studies of the soft tissues on the chest and shoulder girdle. To learn the reasons for the contrast between the nerves and adjacent tissues, the authors obtained a fresh specimen containing part of the brachial plexus nerves from the left axilla and compared MRI with x-ray projections and photomicrographs of histologic sections. The results suggest that the high signals from the nerves stand out in contrast to the low signals from their rich vascular supply. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6A Figure 6B Figure 7 PMID:2733051

  13. [Imaging anatomy of cranial nerves].

    PubMed

    Hermier, M; Leal, P R L; Salaris, S F; Froment, J-C; Sindou, M

    2009-04-01

    Knowledge of the anatomy of the cranial nerves is mandatory for optimal radiological exploration and interpretation of the images in normal and pathological conditions. CT is the method of choice for the study of the skull base and its foramina. MRI explores the cranial nerves and their vascular relationships precisely. Because of their small size, it is essential to obtain images with high spatial resolution. The MRI sequences optimize contrast between nerves and surrounding structures (cerebrospinal fluid, fat, bone structures and vessels). This chapter discusses the radiological anatomy of the cranial nerves.

  14. Accessory nerve palsy.

    PubMed

    Olarte, M; Adams, D

    1977-11-01

    After apparently uncomplicated excision of benign lesions in the posterior cervical triangle, two patients had shoulder pain. In one, neck pain and trapezius weakness were not prominent until one month after surgery. Inability to elevate the arm above the horizontal without externally rotating it, and prominent scapular displacement on arm abduction, but not on forward pushing movements, highlighted the trapezius dysfunction and differentiated it from serratus anterior weakness. Spinal accessory nerve lesions should be considered when minor surgical procedures, lymphadenitis, minor trauma, or tumours involved the posterior triangle of the neck.

  15. Pattern of Peripheral Nerve Involvement in Spinocerebellar Ataxia Type 2: a Neurophysiological Assessment.

    PubMed

    Bezerra, Marcio Luiz Escorcio; Pedroso, José Luiz; Braga-Neto, Pedro; Abrahao, Agessandro; de Albuquerque, Marcus Vinicius Cristino; Borges, Franklin Roberto Pereira; Saraiva-Pereira, Maria Luiza; Jardim, Laura Bannach; de Oliveira Braga, Nadia Iandoli; Manzano, Gilberto Mastrocola; Barsottini, Orlando G P

    2016-12-01

    Peripheral neuropathy is frequent in spinocerebellar ataxia type 2 (SCA2), but the pattern and characteristics of nerve involvement are still an unsettled issue. This study aimed to evaluate the prevalence, extent, and distribution of nerve involvement in SCA2 patients through neurophysiological studies. Thirty-one SCA2 patients and 20 control subjects were enrolled in this study. All subjects were prospectively evaluated through electromyography, including nerve conduction, needle electromyography in proximal and distal muscles of the upper and lower limbs, and sural radial amplitude ratio (SRAR). We aimed to differentiate distal axonopathy from diffuse nerve commitment, characterizing neuronopathy. Nerve involvement was observed in 83.6 % (26 individuals) of SCA2 patients. Among these, 19 had diffuse sensory abnormalities on nerve conduction predominantly on the upper limbs, with diffuse chronic denervation on needle electromyography and elevated SRAR values. Four individuals had only diffuse sensory involvement, and 2 had only motor involvement on needle evaluation and normal nerve conduction. These were interpreted as neuronopathy due to the diffuse distribution of the involvement. One individual had distal sensory axonopathy, with lower limb predominance. In this study, we found neuronopathy as the main pattern of nerve involvement in SCA2 patients and that motor involvement is a frequent feature. This information brings new insights into the understanding of the pathophysiology of nerve involvement in SCA2 and sets some key points about the phenotype, which is relevant to guide the genetic/molecular diagnosis.

  16. Polymers & People

    ERIC Educational Resources Information Center

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  17. Six3 regulates optic nerve development via multiple mechanisms.

    PubMed

    Samuel, Anat; Rubinstein, Ariel M; Azar, Tehila T; Ben-Moshe Livne, Zohar; Kim, Seok-Hyung; Inbal, Adi

    2016-01-29

    Malformations of the optic nerve lead to reduced vision or even blindness. During optic nerve development, retinal ganglion cell (RGC) axons navigate across the retina, exit the eye to the optic stalk (OS), and cross the diencephalon midline at the optic chiasm en route to their brain targets. Many signalling molecules have been implicated in guiding various steps of optic nerve pathfinding, however much less is known about transcription factors regulating this process. Here we show that in zebrafish, reduced function of transcription factor Six3 results in optic nerve hypoplasia and a wide repertoire of RGC axon pathfinding errors. These abnormalities are caused by multiple mechanisms, including abnormal eye and OS patterning and morphogenesis, abnormal expression of signalling molecules both in RGCs and in their environment and anatomical deficiency in the diencephalic preoptic area, where the optic chiasm normally forms. Our findings reveal new roles for Six3 in eye development and are consistent with known phenotypes of reduced SIX3 function in humans. Hence, the new zebrafish model for Six3 loss of function furthers our understanding of the mechanisms governing optic nerve development and Six3-mediated eye and forebrain malformations.

  18. Medial antebrachial cutaneous nerve injury after brachial plexus block: two case reports.

    PubMed

    Jung, Mi Jin; Byun, Ha Young; Lee, Chang Hee; Moon, Seung Won; Oh, Min-Kyun; Shin, Heesuk

    2013-12-01

    Medial antebrachial cutaneous (MABC) nerve injury associated with iatrogenic causes has been rarely reported. Local anesthesia may be implicated in the etiology of such injury, but has not been reported. Two patients with numbness and painful paresthesia over the medial aspect of the unilateral forearm were referred for electrodiagnostic study, which revealed MABC nerve lesion in each case. The highly selective nature of the MABC nerve injuries strongly suggested that they were the result of direct nerve injury by an injection needle during previous brachial plexus block procedures. Electrodiagnostic studies can be helpful in evaluating cases of sensory disturbance after local anesthesia. To our knowledge, these are the first documented cases of isolated MABC nerve injury following ultrasound-guided axillary brachial plexus block.

  19. Peripheral nerve injury grading simplified on MR neurography: As referenced to Seddon and Sunderland classifications.

    PubMed

    Chhabra, Avneesh; Ahlawat, Shivani; Belzberg, Allan; Andreseik, Gustav

    2014-07-01

    The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment. While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene. With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems. The article discusses peripheral nerve anatomy, pathophysiology of nerve injury, traditional grading systems for classifying the severity of nerve injury, and the role of MR neurography in this domain, with respective clinical and surgical correlations, as one follows the anatomic paths of various nerve injury grading systems.

  20. Peripheral nerve injury grading simplified on MR neurography: As referenced to Seddon and Sunderland classifications

    PubMed Central

    Chhabra, Avneesh; Ahlawat, Shivani; Belzberg, Allan; Andreseik, Gustav

    2014-01-01

    The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment. While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene. With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems. The article discusses peripheral nerve anatomy, pathophysiology of nerve injury, traditional grading systems for classifying the severity of nerve injury, and the role of MR neurography in this domain, with respective clinical and surgical correlations, as one follows the anatomic paths of various nerve injury grading systems. PMID:25114384

  1. Long thoracic nerve injury.

    PubMed

    Wiater, J M; Flatow, E L

    1999-11-01

    Injury to the long thoracic nerve causing paralysis or weakness of the serratus anterior muscle can be disabling. Patients with serratus palsy may present with pain, weakness, limitation of shoulder elevation, and scapular winging with medial translation of the scapula, rotation of the inferior angle toward the midline, and prominence of the vertebral border. Long thoracic nerve dysfunction may result from trauma or may occur without injury. Fortunately, most patients experience a return of serratus anterior function with conservative treatment, but recovery may take as many as 2 years. Bracing often is tolerated poorly. Patients with severe symptoms in whom 12 months of conservative treatment has failed may benefit from surgical reconstruction. Although many surgical procedures have been described, the current preferred treatment is transfer of the sternal head of the pectoralis major tendon to the inferior angle of the scapula reinforced with fascia or tendon autograft. Many series have shown good to excellent results, with consistent improvement in function, elimination of winging, and reduction of pain.

  2. Facial nerve palsy due to birth trauma

    MedlinePlus

    Seventh cranial nerve palsy due to birth trauma; Facial palsy - birth trauma; Facial palsy - neonate; Facial palsy - infant ... infant's facial nerve is also called the seventh cranial nerve. It can be damaged just before or at ...

  3. Functions of the Renal Nerves.

    ERIC Educational Resources Information Center

    Koepke, John P.; DiBona, Gerald F.

    1985-01-01

    Discusses renal neuroanatomy, renal vasculature, renal tubules, renin secretion, renorenal reflexes, and hypertension as related to renal nerve functions. Indicates that high intensitites of renal nerve stimulation have produced alterations in several renal functions. (A chart with various stimulations and resultant renal functions and 10-item,…

  4. Neuromas of the calcaneal nerves.

    PubMed

    Kim, J; Dellon, A L

    2001-11-01

    A neuroma of a calcaneal nerve has never been reported. A series of 15 patients with heel pain due to a neuroma of a calcaneal nerve are reviewed. These patients previously had either a plantar fasciotomy (n = 4), calcaneal spur removal (n = 2), ankle fusion (n = 2), or tarsal tunnel decompression (n = 7). Neuromas occurred on calcaneal branches that arose from either the posterior tibial nerve (n = 1), lateral plantar nerve (n = 1), the medial plantar nerve (n = 9), or more than one of these nerves (n = 4). Operative approach was through an extended tarsal tunnel incision to permit identification of all calcaneal nerves. The neuroma was resected and implanted into the flexor hallucis longus muscle. Excellent relief of pain occurred in 60%, and good relief in 33%. One patient (17%) had no improvement and required resection of the lateral plantar nerve. Awareness that the heel may be innervated by multiple calcaneal branches suggests that surgery for heel pain of neural origin employ a surgical approach that permits identification of all possible calcaneal branches.

  5. Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes.

    PubMed

    Piao, Chengdong; Li, Peng; Liu, Guangyao; Yang, Kun

    2013-11-25

    Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. Ten sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds, the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require-ments for a biomaterial used to repair sciatic nerve injury.

  6. Collagen nerve conduits promote enhanced axonal regeneration, schwann cell association, and neovascularization compared to silicone conduits.

    PubMed

    Kemp, Stephen W P; Syed, Shahbaz; Walsh, Walsh; Zochodne, Douglas W; Midha, Rajiv

    2009-08-01

    Peripheral nerve regeneration within guidance conduits involves a critical association between regenerating axons, Schwann cells (SCs), and neovascularization. However, it is currently unknown if there is a greater association between these factors in nonpermeable versus semipermeable nerve guide conduits. We therefore examined this collaboration in both silicone- and collagen-based nerve conduits in both 5- and 10-mm-injury gaps in rat sciatic nerves. Results indicate that collagen conduits promoted enhanced axonal and SC regeneration and association when compared to silicone conduits in the shorter 5-mm-gap model. In addition, collagen tubes displayed enhanced neovascularization over silicone conduits, suggesting that these three factors are intimately related in successful peripheral nerve regeneration. At later time points (1- and 2-month analysis) in a 10-mm-gap model, collagen tubes displayed enhanced axonal regeneration, myelination, and vascularization when compared to silicone-based conduits. Results from these studies suggest that regenerating cables within collagen-based conduits are revascularized earlier and more completely, which in turn enhances peripheral nerve regeneration through these nerve guides as compared to silicone conduits.

  7. Nerve glue for upper extremity reconstruction.

    PubMed

    Tse, Raymond; Ko, Jason H

    2012-11-01

    Nerve glue is an attractive alternative to sutures to improve the results of nerve repair. Improved axon alignment, reduced scar and inflammation, greater and faster reinnervation, and better functional results have been reported with the use of nerve glue. The different types of nerve glue and the evidence to support or oppose their use are reviewed. Although the ideal nerve glue has yet to be developed, fibrin sealants can be used as nerve glue in select clinical situations. Technology to allow suture-free nerve repair is one development that can potentially improve functional nerve recovery and the outcomes of upper extremity reconstruction.

  8. Facial nerve rerouting in skull base surgery.

    PubMed

    Parhizkar, Nooshin; Hiltzik, David H; Selesnick, Samuel H

    2005-08-01

    Facial nerve rerouting techniques were developed to facilitate re-section of extensive tumors occupying the skull base. Facial nerve rerouting has its own limitations and risks, requiring microsurgical expertise, additional surgical time, and often some degree of facial nerve paresis. This article presents different degrees of anterior and posterior facial nerve rerouting, techniques of facial nerve rerouting, and a comprehensive review of outcomes. It then reviews anatomic and functional preservation of the facial nerve in acoustic neuroma resection, technical aspects of facial nerve dissection, intracranial facial nerve repair options, and outcomes for successful acoustic neuroma surgery.

  9. Polynorbornene derived 8-hydroxyquinoline paper strips for ultrasensitive chemical nerve agent surrogate sensing.

    PubMed

    Sarkar, Santu; Shunmugam, Raja

    2014-08-11

    The detection of nerve agent simulants is achieved by the photoinduced electron transfer (PET) mechanism. A "turn-on" fluorescence response upon phosphorylation at 8-hydroxyquinoline of norbornene-based triazolyl functionalized 8-hydroxyquinoline () followed by intramolecular rearrangement provides very intense green emission. The detection limit of polymer () coated paper strips is 25 ppb with instantaneous response.

  10. Anterior cutaneous nerve entrapment syndrome: management challenges

    PubMed Central

    Chrona, Eleni; Kostopanagiotou, Georgia; Damigos, Dimitrios; Batistaki, Chrysanthi

    2017-01-01

    Anterior cutaneous nerve entrapment syndrome (ACNES) is a commonly underdiagnosed and undertreated chronic state of pain. This syndrome is characterized by the entrapment of the cutaneous branches of the lower thoracoabdominal intercostal nerves at the lateral border of the rectus abdominis muscle, which causes severe, often refractory, chronic pain. This narrative review aims to identify the possible therapeutic strategies for the management of the syndrome. Seventeen studies about ACNES therapy were reviewed; of them, 15 were case–control studies, case series, or case reports, and two were randomized controlled trials. The presently available management strategies for ACNES include trigger point injections (diagnostic and therapeutic), ultrasound-guided blocks, chemical neurolysis, and surgical neurectomy, in combination with systemic medication, as well as some emerging techniques, such as radiofrequency ablation and neuromodulation. An increased awareness of the syndrome and the use of specific diagnostic criteria for its recognition are required to facilitate an early and successful management. This review compiles the proposed management strategies for ACNES. PMID:28144159

  11. Lumbosacral nerve root avulsion.

    PubMed

    Chin, C H; Chew, K C

    1997-01-01

    Lumbosacral nerve root avulsion is a rare clinical entity. Since the first description in 1955, only 35 cases have been reported. It is often associated with pelvic fractures and may be missed in the initial clinical examination as these patients usually present with multiple injuries. We present three such cases with clinical and radiological findings. These patients were involved in road traffic accidents. Two had fractures of the sacroiliac joint with diastasis of the symphysis pubis (Tile type C 1.2) and one had fractures of the public rami (Tile type B 2.1). All three had various degrees of sensory and motor deficit of the lower limbs. Lumbar myelogram shows characteristic pseudomeningoceles in the affected lumboscral region. Magnetic resonance (MR) imaging provides an additional non-invasive modality to diagnose this condition.

  12. Recovery of erectile function comparing autologous nerve grafts, unseeded conduits, Schwann-cell-seeded guidance tubes and GDNF-overexpressing Schwann cell grafts

    PubMed Central

    Buchner, Alexander; Matiasek, Kaspar; Schlenker, Boris; Stief, Christian; Weidner, Norbert

    2016-01-01

    ABSTRACT Dissection of the cavernous nerves during radical prostatectomy for prostate cancer eliminates spontaneous erections. Using the rat as an experimental model, we compared the regenerative capacity of autologous nerve grafts and Schwann-cell-seeded nerve guides. After bilateral excision of cavernous nerve segments, cavernous nerves were reconstructed using unseeded silicon tubes, nerve autografts and silicon tubes seeded with either Glial-cell-line-derived (GDNF)-overexpressing or green fluorescent protein (GFP)-expressing Schwann cells (SCs) (16 study nerves per group). Control groups underwent either a sham operation or bilateral excision of cavernous nerve segments without repair. After 12 weeks erectile function was assessed by neurostimulation and intracavernous pressure (ICP) measurement. The reconstructed nerve segments were excised and histologically analyzed. We demonstrated an intact erectile response upon neurostimulation in 25% (4/16) of autologous nerve grafts, in 50% (8/16) of unseeded tubes, in 75% (12/16) of the Schwann-cell–GFP group and in 93.75% (15/16) of the GDNF group. ICP was significantly increased when comparing the Schwann-cell–GFP group with nerve autografts, unseeded conduits and negative controls (P<0.005). In conclusion, Schwann-cell-seeded scaffolds combined with neurotrophic factors are superior to unseeded tubes and autologous nerve grafts. They present a promising therapeutic approach for the repair of erectile nerve gaps. PMID:27874834

  13. Biological activity of ionene polymers

    NASA Technical Reports Server (NTRS)

    Rembaum, A.

    1973-01-01

    Ionene polymers are polyammonium salts with positive nitrogens in the backbone, resulting from the polycondensation of diamines with dihalides or from the polycondensation of halo amines. The mechanism of formation of ionene polymers of different structures and their biological activity is reviewed. The antimicrobial and antifungal properties are compared with low molecular weight ammonium salts. Ionenes were found to combine with DNA by means of ionic bonds to yield similar complexes to those obtained with polyamines (spermine and spermidine). They also combine with nerve cell receptors and exercise a more powerful and longer duration ganglionic blocking action than their monomeric analogs. The antiheparin activity of ionenes and the thromboresistance of elastomeric ionene heparin coatings is described. The enhanced biological activity of ionenes as compared with low molecular weight compounds is attributed to a cooperative effect of a large number of positive charges on the polymeric chains.

  14. Organometallic Polymers.

    ERIC Educational Resources Information Center

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  15. Polymer flooding

    SciTech Connect

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  16. [Post-traumatic infraorbital nerve neuropathy].

    PubMed

    Sakavicius, Dalius; Kubilius, Ricardas; Sabalys, Gintautas

    2002-01-01

    The authors have investigated functional state of infraorbital nerve of 479 patients with zygomatic fractures. The degree of nerve damage was evaluated according to changes of pain threshold during damaged nerve stimulation. It was estimated that in 64.3% of zygomatic fractures the infraorbital nerve was affected. The nerve damage degree could be mild, moderate and severe. In 43.18% of moderate and severe nerve damage cases the neuropathy develops. The symptoms, signs and treatment of neuropathy have been described. The neuropathy with clinical symptoms as permanent soreness and paresthesias (itch, "running ant", fibrillations of cheek tissues etc.) in the infraorbital nerve innervation zone occur to 43.18% of the patients after moderate and severe damage of the nerve. The treatment of neuropathy was analysed. In cases of moderate and severe nerve damages, authors recommend to perform decompression of the nerve, because if not applied, the function of nerve does not recover.

  17. A Flat Interface Nerve Electrode With Integrated Multiplexer

    PubMed Central

    Lertmanorat, Zeng; Montague, F. W; Durand, Dominique M.

    2009-01-01

    One of the goals of peripheral nerve cuff electrode development is the design of an electrode capable of selectively activating a specific population of axons in a common nerve trunk. Several designs such as the round spiral electrode or the flat interface nerve electrode (FINE) have shown such ability. However, multiple contact electrodes require many leads, making the implantation difficult and potentially damaging to the nerve. Taking advantage of the flat geometry of the FINE, multiplexers were embedded within the cuff electrode to reduce the number of leads needed to control thirty two channels. The circuit was implemented on a polyimide film using off-the-shelf electronic components. The electronic module was surface-mounted directly onto the electrode’s flat substrate. Two circuit designs were designed, built and tested; 1) a single supply design with only two wires but limited to cathodic-first pulse and 2) a dual-supply design requiring three lead wires but an arbitrary stimulation waveform. The electrode design includes thirty-two contacts in a 1mm×8mm opening. The contact size is 300μm ×400μm with access resistance less than 1kΩ. This electrode is not intended for long-term use, but developed as a feasibility study for future development using low-water-absorption materials such as liquid crystal polymer and an application specific integrated circuit. PMID:19362897

  18. Spider Silk Constructs Enhance Axonal Regeneration and Remyelination in Long Nerve Defects in Sheep

    PubMed Central

    Radtke, Christine; Allmeling, Christina; Waldmann, Karl-Heinz; Reimers, Kerstin; Thies, Kerstin; Schenk, Henning C.; Hillmer, Anja; Guggenheim, Merlin; Brandes, Gudrun; Vogt, Peter M.

    2011-01-01

    Background Surgical reapposition of peripheral nerve results in some axonal regeneration and functional recovery, but the clinical outcome in long distance nerve defects is disappointing and research continues to utilize further interventional approaches to optimize functional recovery. We describe the use of nerve constructs consisting of decellularized vein grafts filled with spider silk fibers as a guiding material to bridge a 6.0 cm tibial nerve defect in adult sheep. Methodology/Principal Findings The nerve constructs were compared to autologous nerve grafts. Regeneration was evaluated for clinical, electrophysiological and histological outcome. Electrophysiological recordings were obtained at 6 months and 10 months post surgery in each group. Ten months later, the nerves were removed and prepared for immunostaining, electrophysiological and electron microscopy. Immunostaining for sodium channel (NaV 1.6) was used to define nodes of Ranvier on regenerated axons in combination with anti-S100 and neurofilament. Anti-S100 was used to identify Schwann cells. Axons regenerated through the constructs and were myelinated indicating migration of Schwann cells into the constructs. Nodes of Ranvier between myelin segments were observed and identified by intense sodium channel (NaV 1.6) staining on the regenerated axons. There was no significant difference in electrophysiological results between control autologous experimental and construct implantation indicating that our construct are an effective alternative to autologous nerve transplantation. Conclusions/Significance This study demonstrates that spider silk enhances Schwann cell migration, axonal regrowth and remyelination including electrophysiological recovery in a long-distance peripheral nerve gap model resulting in functional recovery. This improvement in nerve regeneration could have significant clinical implications for reconstructive nerve surgery. PMID:21364921

  19. Discovery Guide.

    ERIC Educational Resources Information Center

    Edwards, Claudia

    This guide describes a project (Teamwork Approach to Better Schools) developed to promote the establishment of a formal teacher support network in a variety of schools within a local support district. The model is a guide to newcomers to the project, helping eliminate startup problems and providing a sound base of experiences. The program began…

  20. Nerve cuff electrode using embedded magnets and its application to hypoglossal nerve stimulation

    NASA Astrophysics Data System (ADS)

    Seo, Jungmin; Hye Wee, Jee; Hoan Park, Jeong; Park, Pona; Kim, Jeong-Whun; Kim, Sung June

    2016-12-01

    Objective. A novel nerve cuff electrode with embedded magnets was fabricated and developed. In this study, a pair of magnets was fully embedded and encapsulated in a liquid crystal polymer (LCP) substrate to utilize magnetic force in order to replace the conventional installing techniques of cuff electrodes. In vitro and in vivo experiments were conducted to evaluate the feasibility of the magnet-embedded nerve cuff electrode (MENCE). Lastly, several issues pertaining to the MENCE such as the cuff-to-nerve diameter ratio, the force of the magnets, and possible concerns were discussed in the discussion section. Approach. Electrochemical impedance spectrum and cyclic voltammetry assessments were conducted to measure the impedance and charge storage capacity of the cathodal phase (CSCc). The MENCE was installed onto the hypoglossal nerve (HN) of a rabbit and the movement of the genioglossus was recorded through C-arm fluoroscopy while the HN was stimulated by a pulsed current. Main results. The measured impedance was 0.638 ∠ -67.8° kΩ at 1 kHz and 5.27 ∠ -82.1° kΩ at 100 Hz. The average values of access resistance and cut-off frequency were 0.145 kΩ and 3.98 kHz, respectively. The CSCc of the electrode was measured as 1.69 mC cm-2 at the scan rate of 1 mV s-1. The movement of the genioglossus contraction was observed under a pulsed current with an amplitude level of 0.106 mA, a rate of 0.635 kHz, and a duration of 0.375 ms applied through the MENCE. Significance. A few methods to close and secure cuff electrodes have been researched, but they are associated with several drawbacks. To overcome these, we used magnetic force as a closing method of the cuff electrode. The MENCE can be precisely installed on a target nerve without any surgical techniques such as suturing or molding. Furthermore, it is convenient to remove the installed MENCE because it requires little force to detach one magnet from the other, enabling repeatable installation and removal. We

  1. Solitary fibrous tumour of the vagus nerve.

    PubMed

    Scholsem, Martin; Scholtes, Felix

    2012-04-01

    We describe the complete removal of a foramen magnum solitary fibrous tumour in a 36-year-old woman. It originated on a caudal vagus nerve rootlet, classically described as the 'cranial' accessory nerve root. This ninth case of immunohistologically confirmed cranial or spinal nerve SFT is the first of the vagus nerve.

  2. Surgical management of painful peripheral nerves.

    PubMed

    Elliot, David

    2014-07-01

    This article deals with the classification, assessment, and management of painful nerves of the distal upper limb. The author's preferred surgical and rehabilitation techniques in managing these conditions are discussed in detail and include (1) relocation of end-neuromas to specific sites, (2) division and relocation of painful nerves in continuity (neuromas-in-continuity and scar-tethered nerves) involving small nerves to the same sites, and (3) fascial wrapping of painful nerves in continuity involving larger nerves such as the median and ulnar nerves. The results of these treatments are presented as justification for current use of these techniques.

  3. Overview of Optic Nerve Disorders

    MedlinePlus

    ... where the problem is in the pathway. Visual Pathways and the Consequences of Damage Nerve signals travel ... eyes. Damage to an eye or the visual pathway causes different types of vision loss depending on ...

  4. Nerve entrapment and gene therapy.

    PubMed

    Sud, Vipul

    2002-01-01

    Peripheral entrapment neuropathy is a common cause of upper-extremity pain, paresthesias, and weakness. Although any of the major nerves can be affected, compression of the median nerve at the carpal tunnel is the commonest site of clinically significant nerve compression. Etiologically, carpal tunnel syndrome (CTS) has numerous causes, but the idiopathic group greatly outnumbers the rest. Moreover, the pathophysiology of CTS patients claiming work-related repetitive hand motion as a basis for their disorder has been the subject of intensive study because of its economic ramifications for industry. CTS can serve as a model for reviewing the pathophysiology and biochemical changes of the nerve and its exterior milieu at the cellular level, as well as the possibilities of modifying these changes at the molecular level.

  5. Schwannomatosis of Cervical Vagus Nerve

    PubMed Central

    Sasi, M. P.

    2016-01-01

    Cervical vagal schwannoma is a rare entity among lesions presenting as a neck mass. They are usually slow-growing benign lesions closely associated with the vagus nerve. They are usually solitary and asymptomatic. Multiple schwannomas occurring in patients without neurofibromatosis (NF) are rare and have recently been referred to as schwannomatosis. Here, we present a case of a neck mass that had imaging features suggestive of vagal schwannoma and was operated upon. Intraoperatively, it was discovered to be a case of multiple vagal cervical schwannoma, all directly related to the right vagus nerve, and could be resected from the nerve in toto preserving the function of the vagus nerve. Final HPR confirmed our pre-op suspicion of vagal schwannomatosis. PMID:27807496

  6. Ultrasound-guided bilateral combined inguinal femoral and subgluteal sciatic nerve blocks for simultaneous bilateral below-knee amputations due to bilateral diabetic foot gangrene unresponsive to peripheral arterial angioplasty and bypass surgery in a coagulopathic patient on antiplatelet therapy with a history of percutaneous coronary intervention for ischemic heart disease

    PubMed Central

    Byun, Sung Hye; Lee, Jonghoon; Kim, Jong Hae

    2016-01-01

    Abstract Background: Patients on antiplatelet therapy following percutaneous coronary intervention can become coagulopathic due to infection. Performing regional anesthesia for bilateral surgery in such cases is challenging. We report a case of successful combined inguinal femoral and subgluteal sciatic nerve blocks (CFSNBs) for simultaneous bilateral below-knee amputations in a coagulopathic patient on antiplatelet therapy. Methods: A 70-year-old male patient presented with pain in both feet due to diabetic foot syndrome. The condition could not be managed by open amputations of the toes at the metatarsal bones and subsequent antibiotic therapy. Computed tomographic angiography showed significant stenosis in the arteries supplying the lower limbs, indicating atherosclerotic gangrene in both feet. Balloon angioplasty and bypass surgery with subsequent debridements with application of negative-pressure wound therapy and additional open amputations did not improve the patient's clinical condition: his leukocyte counts and C-reactive protein levels were above the normal range, and his prothrombin and activated partial thromboplastin times were increased. Results: Simultaneous bilateral below-knee amputations were performed under ultrasound-guided CFSNBs. Following left CFSNBs using 45 mL of a local anesthetic mixture (1:1 ratio of 1.0% mepivacaine and 0.75% ropivacaine), the left below-knee amputation was performed for 76 minutes. Subsequently, under right CFSNBs using 47 mL of the local anesthetic mixture, the right below-knee amputation proceeded for 85 minutes. Throughout each surgery, dexmedetomidine was continuously administered, and a sensory blockade was well maintained in both limbs. The patient did not complain of pain due to regression of the first CFSNBs during the second surgery. The CFSNBs successfully prevented tourniquet pain. Local anesthetic systemic toxicity (LAST) and hemodynamic instability due to tourniquet deflation and administration of

  7. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2015-10-01

    regeneration using our approach with an acellular nerve allograft to be equivalent to standard autograft repair in rodent models. An ongoing large animal ...be clinically acceptable for use in the animal studies in Aim 2. The anatomy of HAM is shown pictorially in Figure 7. In vivo, the epithelial...product. Given that the large animal studies with large caliber nerves in Aim 3 will use AxoGuard we feel that the single layer SIS material is totally

  8. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2013-10-01

    around the nerve ends performed following application of 0.1% Rose Bengal dye in saline to wrap and epineurium with illumination at 532 nm. The HAM...results obtained with the three fixation methods under study (a) epineurial suture, (b) fibrin glue and (c) photochemical tissue bonding (PTB) with a...wrap material. All methods induced bonding between the nerve segments with bond strength in the order of suture>PTB> fibrin glue. Conventional

  9. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2013-10-01

    performed following application of 0.1% Rose Bengal dye in saline to wrap and epineurium with illumination at 532 nm. The HAM wrap/nerve sample was then...the three fixation methods under study (a) epineurial suture, (b) fibrin glue and (c) photochemical tissue bonding (PTB) with a wrap material. All...methods induced bonding between the nerve segments with bond strength in the order of suture>PTB> fibrin glue. Conventional epineurial suturing using

  10. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2013-10-01

    harvested from donor rats immediately post-euthanasia (Task 1g) and bonding of the wrap around the nerve ends performed following application of 0.1...a) epineurial suture, (b) fibrin glue and (c) photochemical tissue bonding (PTB) with a wrap material. All methods induced bonding between the nerve...segments with bond strength in the order of suture>PTB> fibrin glue. Conventional epineurial suturing using six 10.0 nylon sutures resulted in the

  11. [Peripheral Nerve Injuries in Sports].

    PubMed

    Tettenborn, B; Mehnert, S; Reuter, I

    2016-09-01

    Peripheral nerve injuries due to sports are relatively rare but the exact incidence is not known due to a lack of epidemiological studies. Particular sports activities tend to cause certain peripheral nerve injuries including direct acute compression or stretching, repetitive compression and stretching over time, or another mechanism such as ischemia or laceration. These nerve lesions may be severe and delay or preclude the athlete's return to sports, especially in cases with delayed diagnosis. Repetitive and vigorous use or overuse makes the athlete vulnerable to disorders of the peripheral nerves, and sports equipment may cause compression of the nerves. Depending on etiology, the treatment is primarily conservative and includes physiotherapy, modification of movements and sports equipment, shoe inserts, splinting, antiphlogistic drugs, sometimes local administration of glucocorticoids or, lately, the use of extracorporeal shock waves. Most often, cessation of the offending physical activity is necessary. Surgery is only indicated in the rare cases of direct traumatic nerve injury or when symptoms are refractory to conservative therapy. Prognosis mainly depends on the etiology and the available options of modifying measures.This article is based on the publications "Reuter I, Mehnert S. Engpasssyndrome peripherer Nerven bei Sportlern". Akt Neurol 2012;39:292-308 and Sportverl Sportschad 2013;27:130-146.

  12. Antimocrobial Polymer

    DOEpatents

    McDonald, William F.; Huang, Zhi-Heng; Wright, Stacy C.

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  13. Antimicrobial Polymer

    DOEpatents

    McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2004-09-28

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one example embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl; and the metallic antimicrobial agent is selected from chelated silver ions, silver metal, chelated copper ions, copper metal, chelated zinc ions, zinc metal and mixtures thereof.

  14. Polymer inflation

    NASA Astrophysics Data System (ADS)

    Hassan, Syed Moeez; Husain, Viqar; Seahra, Sanjeev S.

    2015-03-01

    We consider the semiclassical dynamics of a free massive scalar field in a homogeneous and isotropic cosmological spacetime. The scalar field is quantized using the polymer quantization method assuming that it is described by a Gaussian coherent state. For quadratic potentials, the semiclassical equations of motion yield a universe that has an early "polymer inflation" phase which is generic and almost exactly de Sitter, followed by an epoch of slow-roll inflation. We compute polymer corrections to the slow-roll formalism, and discuss the probability of inflation in this model using a physical Hamiltonian arising from time gauge fixing. We also show how in this model, it is possible to obtain a significant amount of slow-roll inflation from sub-Planckian initial data, hence circumventing some of the criticisms of standard scenarios. These results show the extent to which a quantum gravity motivated quantization method affects early universe dynamics.

  15. Axon-Sorting Multifunctional Nerve Guides: Accelerating Restoration of Nerve Function

    DTIC Science & Technology

    2014-10-01

    design for E . coli based expression. The variants include dual binding domains for heparin sulfate and / or laminin. 25-Mar-2014 • Completed...distribution unlimited The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an...5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) LTC Luis Alvarez, PhD 5d. PROJECT NUMBER 5e. TASK NUMBER E -Mail: luis.m.alvarez4.mil@mail.mi 5f. WORK

  16. Colostomy Guide

    MedlinePlus

    ... Side Effects Managing Cancer-related Side Effects Ostomies Colostomy Guide Colostomy surgery is done for many different diseases and problems. Some colostomies are done because of cancer; others are not. ...

  17. Platysma Motor Nerve Transfer for Restoring Marginal Mandibular Nerve Function

    PubMed Central

    Jensson, David; Weninger, Wolfgang J.; Schmid, Melanie; Meng, Stefan; Tzou, Chieh-Han John

    2016-01-01

    Background: Injuries of the marginal mandibular nerve (MMN) of the facial nerve result in paralysis of the lower lip muscle depressors and an asymmetrical smile. Nerve reconstruction, when possible, is the method of choice; however, in cases of long nerve gaps or delayed nerve reconstruction, conventional nerve repairs may be difficult to perform or may provide suboptimal outcomes. Herein, we investigate the anatomical technical feasibility of transfer of the platysma motor nerve (PMN) to the MMN for restoration of lower lip function, and we present a clinical case where this nerve transfer was successfully performed. Methods: Ten adult fresh cadavers were dissected. Measurements included the number of MMN and PMN branches, the maximal length of dissection of the PMN from the parotid, and the distance from the anterior border of the parotid to the facial artery. The PMN reach for direct coaptation to the MMN at the level of the crossing with the facial artery was assessed. We performed histomorphometric analysis of the MMN and PMN branches. Results: The anatomy of the MMN and PMN was consistent in all dissections, with an average number of subbranches of 1.5 for the MMN and 1.2 for the PMN. The average maximal length of dissection of the PMN was 46.5 mm, and in every case, tension-free coaptation with the MMN was possible. Histomorphometric analysis demonstrated that the MMN contained an average of 3,866 myelinated fiber counts per millimeter, and the PMN contained 5,025. After a 3-year follow-up of the clinical case, complete recovery of MMN function was observed, without the need of central relearning and without functional or aesthetic impairment resulting from denervation of the platysma muscle. Conclusions: PMN to MMN transfer is an anatomically feasible procedure for reconstruction of isolated MMN injuries. In our patient, by direct nerve coaptation, a faster and full recovery of lower lip muscle depressors was achieved without the need of central

  18. Tissue-Engineered Nanofibrous Nerve Grafts for Enhancing the Rate of Nerve Regeneration

    DTIC Science & Technology

    2014-10-01

    bioactivity, transport features and mechanics ideal for enhancing the rate of nerve regeneration and healing critical sized nerve defects. We further...scaffolds in bioreactors prior to implantation in rat critical sized nerve defect model. 2. KEYWORDS: nerve regeneration, nerve guidance conduit...for an optimal nerve graft (Figure 1; Figure 2). Different wall thickness was achieved by using 6 different salt sizes . The 0.1mm wall thickness

  19. Piriformis Syndrome With Variant Sciatic Nerve Anatomy: A Case Report.

    PubMed

    Kraus, Emily; Tenforde, Adam S; Beaulieu, Christopher F; Ratliff, John; Fredericson, Michael

    2016-02-01

    A 68-year-old male long distance runner presented with low back and left buttock pain, which eventually progressed to severe and debilitating pain, intermittently radiating to the posterior thigh and foot. A comprehensive workup ruled out possible spine or hip causes of his symptoms. A pelvic magnetic resonance imaging neurogram with complex oblique planes through the piriformis demonstrated variant anatomy of the left sciatic nerve consistent with the clinical diagnosis of piriformis syndrome. The patient ultimately underwent neurolysis with release of the sciatic nerve and partial resection of the piriformis muscle. After surgery the patient reported significant pain reduction and resumed running 3 months later. Piriformis syndrome is uncommon but should be considered in the differential diagnosis for buttock pain. Advanced imaging was essential to guide management.

  20. Antimicrobial polymers.

    PubMed

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  1. Polymer solutions

    DOEpatents

    Krawczyk, Gerhard Erich; Miller, Kevin Michael

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  2. What Protects Certain Nerves from Stretch Injury?

    PubMed

    Schraut, Nicholas B; Walton, Sharon; Bou Monsef, Jad; Shott, Susan; Serici, Anthony; Soulii, Lioubov; Amirouche, Farid; Gonzalez, Mark H; Kerns, James M

    2016-01-01

    The human tibial nerves is less prone to injury following joint arthroplasty compared with the peroneal nerves. Besides the anatomical distribution, other features may confer protection from stretch injury. We therefore examined the size, shape and connective tissue distribution for the two nerves. The tibial and peroneal nerves from each side of nine fresh human cadavers we reharvested mid-thigh. Proximal segments manually stretched 20%-25% were fixed in aldehyde, while the adjacent distal segments were fixed in their natural length. Paraffin sections stained by Masson's trichrome method for connective tissue were examined by light microscopy. Tibial nerves had 2X more fascicles compared with the peroneal, but the axonal content appeared similar. Analysis showed that neither nerve had a significant reduction in cross sectional area of the fascicles following stretch. However, fascicles from stretched tibial nerves become significantly more oval compared with those from unstretched controls and peroneal nerves. Tibial nerves had a greater proportion that was extrafascicular tissue (50-55%) compared with peroneal nerves (38%-42%). This epineurium was typically adipose tissue. Perineurial thickness in both nerves was directly related to fascicular size. Tibial nerves have several unique histological features associated with size, shape and tissue composition compared with the peroneal nerve. We suggest that more fascicles with their tightly bound perineurium and more robust epineurium afford protection against stretch injury. Mechanical studies should clarify how size and shape contribute to nerve protection and/or neurapraxia.

  3. US of the Peripheral Nerves of the Upper Extremity: A Landmark Approach.

    PubMed

    Brown, Jordan M; Yablon, Corrie M; Morag, Yoav; Brandon, Catherine J; Jacobson, Jon A

    2016-01-01

    Ultrasonography (US) has become a first-line modality for the evaluation of the peripheral nerves of the upper extremity. The benefits of US over magnetic resonance (MR) imaging include higher soft-tissue resolution, cost effectiveness, portability, real-time and dynamic imaging, and the ability to scan an entire extremity quickly and efficiently. US can be performed on patients who are not eligible for MR imaging. Metallic implant artifacts are usually not problematic. US has been shown to have equal specificity and greater sensitivity than MR imaging in the evaluation of peripheral nerves. Any abnormal findings can be easily compared with the contralateral side. The published literature has shown that US has demonstrated clinical utility in patients with suspected peripheral nerve disease by guiding diagnostic and therapeutic decisions as well as by confirming electrodiagnostic findings. Common indications for upper extremity peripheral nerve US are the evaluation for injury due to penetrating trauma, entrapment by scar tissue, and tumor. US of the upper extremity is most commonly performed to evaluate carpal and cubital tunnel syndrome. It is important for the radiologist or sonographer to have a detailed knowledge of anatomy and specific anatomic landmarks for each nerve to efficiently and accurately perform an examination. The goal of this article is to introduce readers to the basics of US of the peripheral nerves of the upper extremity with a focus on the median, ulnar, and radial nerves. Common sites of disease and the location of important anatomic landmarks will be reviewed.

  4. Cardiac autonomic nerve distribution and arrhythmia☆

    PubMed Central

    Liu, Quan; Chen, Dongmei; Wang, Yonggang; Zhao, Xin; Zheng, Yang

    2012-01-01

    OBJECTIVE: To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia. DATA RETRIEVAL: A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation as the key words. SELECTION CRITERIA: A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included. MAIN OUTCOME MEASURES: The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase (main markers of cardiac autonomic nerve distribution). In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated. RESULTS: Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system. CONCLUSION: The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in

  5. Extracranial spinal accessory nerve injury.

    PubMed

    Donner, T R; Kline, D G

    1993-06-01

    Eighty-three consecutive patients with extracranial accessory nerve injury seen over a 12-year period are reviewed. The most common etiology was iatrogenic injury to the nerve at the time of previous surgery. Such operations were usually minor in nature and often related to lymph node or benign tumor removal. Examination usually distinguished winging due to trapezius weakness from that of serratus anterior palsy. Trapezius weakness was seen in all cases. Sternocleidomastoid weakness was unusual. Patients with accessory palsy were evaluated by both clinical and electromyographic studies. Patients who exhibited no clinical or electrical evidence of regeneration were operated on (44 cases). Based on intraoperative nerve action potential studies, 8 lesions in continuity had neurolysis alone. Resection with repair either by end-to-end suture or by grafts was necessary in 31 cases. One case had suture removed from nerve, two had nerve placed into target muscle, and two had more proximal neurotization. Function was usually improved in both operative and nonoperative patients. Related anatomy is discussed.

  6. Imaging the ocular motor nerves.

    PubMed

    Ferreira, Teresa; Verbist, Berit; van Buchem, Mark; van Osch, Thijs; Webb, Andrew

    2010-05-01

    The ocular motor nerves (OMNs) comprise the oculomotor, trochlear and the abducens nerves. According to their course, they are divided into four or five anatomic segments: intra-axial, cisternal, cavernous and intra-orbital and, for the abducens nerve, an additional interdural segment. Magnetic resonance imaging is the imaging method of choice in the evaluation of the normal and pathologic ocular motor nerves. CT still plays a limited but important role in the evaluation of the intraosseous portions at the skull base and bony foramina. We describe for each segment of these cranial nerves, the normal anatomy, the most appropriate image sequences and planes, their imaging appearance and pathologic conditions. Magnetic resonance imaging with high magnetic fields is a developing and promising technique. We describe our initial experience with a Phillips 7.0T MRI scanner in the evaluation of the brainstem segments of the OMNs. As imaging becomes more refined, an understanding of the detailed anatomy is increasingly necessary, as the demand on radiology to diagnose smaller lesions also increases.

  7. Rehabilitation of the trigeminal nerve

    PubMed Central

    Iro, Heinrich; Bumm, Klaus; Waldfahrer, Frank

    2005-01-01

    When it comes to restoring impaired neural function by means of surgical reconstruction, sensory nerves have always been in the role of the neglected child when compared with motor nerves. Especially in the head and neck area, with its either sensory, motor or mixed cranial nerves, an impaired sensory function can cause severe medical conditions. When performing surgery in the head and neck area, sustaining neural function must not only be highest priority for motor but also for sensory nerves. In cases with obvious neural damage to sensory nerves, an immediate neural repair, if necessary with neural interposition grafts, is desirable. Also in cases with traumatic trigeminal damage, an immediate neural repair ought to be considered, especially since reconstructive measures at a later time mostly require for interposition grafts. In terms of the trigeminal neuralgia, commonly thought to arise from neurovascular brainstem compression, a pharmaceutical treatment is considered as the state of the art in terms of conservative therapy. A neurovascular decompression of the trigeminal root can be an alternative in some cases when surgical treatment is sought after. Besides the above mentioned therapeutic options, alternative treatments are available. PMID:22073060

  8. Treatment of abdominal nerve entrapment syndrome using a nerve stimulator.

    PubMed Central

    McGrady, E. M.; Marks, R. L.

    1988-01-01

    Seventy-six patients treated at York Pain Relief Clinic for Abdominal Nerve Entrapment Syndrome (ANES) between 1982 and 1986, using aqueous phenol and nerve stimulator control are reviewed. A questionnaire was sent to all the patients who had been discharged from the clinic to try to confirm that the initial improvements had been maintained and 60 patients replied. Group A (n = 44) had been diagnosed with confidence; 95% had gained complete or partial relief of symptoms. Group B (n = 32) had other symptoms making the diagnosis less certain; 50% gained some relief. Clinical presentation of ANES and the method of treatment are described. Images Fig. 1 PMID:2970241

  9. Nerve Agent Sensing Biopolymer Wipe

    DTIC Science & Technology

    2003-04-01

    minutes. Polymer synthesis is complete in less than 10 minutes. The CO2 evolved during the reaction of water and isocyanate lifts the foam to a...concrete, stone and asphalt . Excessive dirt or any material that significantly masks clear viewing of the sensor polymer may invalidate sensor

  10. Ferroelectric all-polymer hollow Bragg fibers for terahertz guidance

    NASA Astrophysics Data System (ADS)

    Skorobogatiy, Maksim; Dupuis, Alexandre

    2007-03-01

    Design of hollow all-polymer Bragg fibers using periodic multilayers of ferroelectric polyvinylidene fluoride (PVDF) polymer and a low loss polycarbonate (PC) polymer is demonstrated. Efficient band gap guiding is predicted near the transverse optical frequency of a PVDF material in the terahertz regime. Optimal reflector designs are investigated in the whole terahertz region. Depending on frequency, the lowest loss hollow Bragg fiber can be one of the following: a photonic crystal fiber guiding in the band gap regime, a metamaterial fiber with a subwavelength reflector period, a single PC, or a PVDF tube.

  11. A Polymer "Pollution Solution" Classroom Activity.

    ERIC Educational Resources Information Center

    Helser, Terry L.

    1996-01-01

    Explains an approach to presenting polymer chemistry to nonmajors that employs polystyrene foam, foam peanuts made from water soluble starch, and water soluble plastic bags. Students are presented with a pollution scenario and are guided to the discovery of solutions. (DDR)

  12. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane.

    PubMed

    Peng, Shih-Wen; Li, Ching-Wen; Chiu, Ing-Ming; Wang, Gou-Jen

    2017-01-01

    Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid) (PLGA) bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is feasible for use in clinical applications.

  13. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane

    PubMed Central

    Peng, Shih-Wen; Li, Ching-Wen; Chiu, Ing-Ming; Wang, Gou-Jen

    2017-01-01

    Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid) (PLGA) bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is feasible for use in clinical applications. PMID:28138239

  14. Embryonic anastomosis between hypoglossal nerves.

    PubMed

    Rodríguez-Vázquez, J F; Mérida-Velasco, J R; Verdugo-López, S; Sanz-Casado, J V; Jiménez-Collado, J

    2009-12-01

    This article presents two cases of anastomosis of hypoglossal nerves in the suprahyoid region in human embryos of CR length 10.75 and 17.5 mm. This variation was studied in two human specimens at this stage of development and compared with the normal arrangement of the hypoglossal nerves in embryos at the same stage. The anastomotic branches were of similar caliber to the main trunks. In both cases the anastomosis was located dorsal to the origin of the geniohyoid muscles and caudal to the genioglossus muscles, lying transversally over the cranial face of the body of the hyoid bone anlage. The anastomosis formed a suprahyoid nerve chiasm on the midline in the embryo of 10.75 mm CR length.

  15. A precision mechanical nerve stimulator

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

    1988-01-01

    An electromechanical device, used to apply and monitor stimulating pulses to a mammalian motor nerve, has been successfully developed at NASA Langley Research Center. Two existing force transducers, a flight skin friction balance and a miniature skin friction balance which were designed for making aerodynamic drag measurements, were modified and incorporated to form this precision instrument. The nerve stimulator is a type one servomechanism capable of applying and monitoring stimulating pulses of 0 to 10 grams with a precision of better than +/- 0.05 grams. Additionally, the device can be independently used to apply stimulating pulses by displacing the nerve from 0 to 0.25 mm with a precision of better than +/- 0.001 mm while measuring the level of the load applied.

  16. Facial nerve paralysis in children

    PubMed Central

    Ciorba, Andrea; Corazzi, Virginia; Conz, Veronica; Bianchini, Chiara; Aimoni, Claudia

    2015-01-01

    Facial nerve palsy is a condition with several implications, particularly when occurring in childhood. It represents a serious clinical problem as it causes significant concerns in doctors because of its etiology, its treatment options and its outcome, as well as in little patients and their parents, because of functional and aesthetic outcomes. There are several described causes of facial nerve paralysis in children, as it can be congenital (due to delivery traumas and genetic or malformative diseases) or acquired (due to infective, inflammatory, neoplastic, traumatic or iatrogenic causes). Nonetheless, in approximately 40%-75% of the cases, the cause of unilateral facial paralysis still remains idiopathic. A careful diagnostic workout and differential diagnosis are particularly recommended in case of pediatric facial nerve palsy, in order to establish the most appropriate treatment, as the therapeutic approach differs in relation to the etiology. PMID:26677445

  17. Nerve lesioning with direct current

    NASA Astrophysics Data System (ADS)

    Ravid, E. Natalie; Shi Gan, Liu; Todd, Kathryn; Prochazka, Arthur

    2011-02-01

    Spastic hypertonus (muscle over-activity due to exaggerated stretch reflexes) often develops in people with stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Lesioning of nerves, e.g. with phenol or botulinum toxin is widely performed to reduce spastic hypertonus. We have explored the use of direct electrical current (DC) to lesion peripheral nerves. In a series of animal experiments, DC reduced muscle force by controlled amounts and the reduction could last several months. We conclude that in some cases controlled DC lesioning may provide an effective alternative to the less controllable molecular treatments available today.

  18. Responsive Guest Encapsulation of Dynamic Conjugated Microporous Polymers.

    PubMed

    Xu, Lai; Li, Youyong

    2016-06-30

    The host-guest complexes of conjugated microporous polymers encapsulating C60 and dye molecules have been investigated systematically. The orientation of guest molecules inside the cavities, have different terms: inside the open cavities of the polymer, or inside the cavities formed by packing different polymers. The host backbone shows responsive dynamic behavior in order to accommodate the size and shape of incoming guest molecule or guest aggregates. Simulations show that the host-guest binding of conjugated polymers is stronger than that of non-conjugated polymers. This detailed study could provide a clear picture for the host-guest interaction for dynamic conjugated microporous polymers. The mechanism obtained could guide designing new conjugated microporous polymers.

  19. Responsive Guest Encapsulation of Dynamic Conjugated Microporous Polymers

    PubMed Central

    Xu, Lai; Li, Youyong

    2016-01-01

    The host-guest complexes of conjugated microporous polymers encapsulating C60 and dye molecules have been investigated systematically. The orientation of guest molecules inside the cavities, have different terms: inside the open cavities of the polymer, or inside the cavities formed by packing different polymers. The host backbone shows responsive dynamic behavior in order to accommodate the size and shape of incoming guest molecule or guest aggregates. Simulations show that the host-guest binding of conjugated polymers is stronger than that of non-conjugated polymers. This detailed study could provide a clear picture for the host-guest interaction for dynamic conjugated microporous polymers. The mechanism obtained could guide designing new conjugated microporous polymers. PMID:27356483

  20. Stimulation of Neurite Outgrowth Using an Electrically Conducting Polymer

    NASA Astrophysics Data System (ADS)

    Schmidt, Christine E.; Shastri, Venkatram R.; Vacanti, Joseph P.; Langer, Robert

    1997-08-01

    Damage to peripheral nerves often cannot be repaired by the juxtaposition of the severed nerve ends. Surgeons have typically used autologous nerve grafts, which have several drawbacks including the need for multiple surgical procedures and loss of function at the donor site. As an alternative, the use of nerve guidance channels to bridge the gap between severed nerve ends is being explored. In this paper, the electrically conductive polymer--oxidized polypyrrole (PP)--has been evaluated for use as a substrate to enhance nerve cell interactions in culture as a first step toward potentially using such polymers to stimulate in vivo nerve regeneration. Image analysis demonstrates that PC-12 cells and primary chicken sciatic nerve explants attached and extended neurites equally well on both PP films and tissue culture polystyrene in the absence of electrical stimulation. In contrast, PC-12 cells interacted poorly with indium tin oxide (ITO), poly(L-lactic acid) (PLA), and poly(lactic acid-coglycolic acid) surfaces. However, PC-12 cells cultured on PP films and subjected to an electrical stimulus through the film showed a significant increase in neurite lengths compared with ones that were not subjected to electrical stimulation through the film and tissue culture polystyrene controls. The median neurite length for PC-12 cells grown on PP and subjected to an electrical stimulus was 18.14 μ m (n = 5643) compared with 9.5 μ m (n = 4440) for controls. Furthermore, animal implantation studies reveal that PP invokes little adverse tissue response compared with poly(lactic acid-coglycolic acid).

  1. Advanced Polymer

    NASA Technical Reports Server (NTRS)

    1992-01-01

    In the mid-1980's, Langley developed a polyimide sulfone, combining desirable properties of two classes of polymers. Composites and other products made from polyimide sulfone can be used with solvents and corrosive fluids, are light weight, low cost and can be easily fabricated for a wide range of industrial uses. High Technology Systems, Inc. obtained a license for the polymer and was awarded a Small Business Innovation Research (SBIR) contract for development in a powder form. Although its principal use is as a matrix resin for composites, the material can also be used as a high temperature structural adhesive for aircraft structures and as a coating for protection from heat and radiation for electronic components.

  2. Theoretical Polymers.

    DTIC Science & Technology

    1976-10-07

    for the correlation length of 3/4, while 0.72 is observed. Then followed several talks on the expansion coefficient a, the virial coefficients and...calculation of the virial coefficient and c~2. These quantities can be considered merely a testing ground for the use of this method to polymer...the second viria]. coefficient , A2, to be zero and the intrinsic viscosity dependent on~VW for polystyrene mole-cular weights between 33,000 and one

  3. Phthalocyanine polymers

    NASA Technical Reports Server (NTRS)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  4. Periodic Polymers

    NASA Astrophysics Data System (ADS)

    Thomas, Edwin

    2013-03-01

    Periodic polymers can be made by self assembly, directed self assembly and by photolithography. Such materials provide a versatile platform for 1, 2 and 3D periodic nano-micro scale composites with either dielectric or impedance contrast or both, and these can serve for example, as photonic and or phononic crystals for electromagnetic and elastic waves as well as mechanical frames/trusses. Compared to electromagnetic waves, elastic waves are both less complex (longitudinal modes in fluids) and more complex (longitudinal, transverse in-plane and transverse out-of-plane modes in solids). Engineering of the dispersion relation between wave frequency w and wave vector, k enables the opening of band gaps in the density of modes and detailed shaping of w(k). Band gaps can be opened by Bragg scattering, anti-crossing of bands and discrete shape resonances. Current interest is in our group focuses using design - modeling, fabrication and measurement of polymer-based periodic materials for applications as tunable optics and control of phonon flow. Several examples will be described including the design of structures for multispectral band gaps for elastic waves to alter the phonon density of states, the creation of block polymer and bicontinuous metal-carbon nanoframes for structures that are robust against ballistic projectiles and quasi-crystalline solid/fluid structures that can steer shock waves.

  5. Medial and Lateral Plantar Nerve Entrapment

    MedlinePlus

    ... Problems Achilles Tendon Bursitis Achilles Tendon Enthesopathy Bunion Corns and Calluses Damage to the Nerves in the ... Problems Achilles Tendon Bursitis Achilles Tendon Enthesopathy Bunion Corns and Calluses Damage to the Nerves in the ...

  6. Vagus Nerve Stimulation for Treating Epilepsy

    MedlinePlus

    ... Evidence-based Guideline for PATIENTS and their FAMILIES VAGUS NERVE STIMULATION FOR TREATING EPILEPSY This information sheet is provided to help you understand how vagus nerve stimulation (VNS) may help treat epilepsy. The American ...

  7. Specialized Nerve Tests: EMG, NCV and SSEP

    MedlinePlus

    ... lowest part of the brain down through the spinal column. In humans, spinal nerves branch off from the ... are grouped according to where they leave the spinal column. There are eight pairs of neck (cervical) nerves, ...

  8. Infraspinatus muscle atrophy from suprascapular nerve compression.

    PubMed

    Cordova, Christopher B; Owens, Brett D

    2014-02-01

    Muscle weakness without pain may signal a nerve compression injury. Because these injuries should be identified and treated early to prevent permanent muscle weakness and atrophy, providers should consider suprascapular nerve compression in patients with shoulder muscle weakness.

  9. Palsies of Cranial Nerves That Control Eye Movement

    MedlinePlus

    ... Medical News Palsies of Cranial Nerves That Control Eye Movement By Michael Rubin, MDCM, Weill Cornell Medical College; ... Gaze Palsies Palsies of Cranial Nerves That Control Eye Movement Third Cranial Nerve (Oculomotor Nerve) Palsy Fourth Cranial ...

  10. Stem cell-based approaches to improve nerve regeneration: potential implications for reconstructive transplantation?

    PubMed

    Khalifian, Saami; Sarhane, Karim A; Tammia, Markus; Ibrahim, Zuhaib; Mao, Hai-Quan; Cooney, Damon S; Shores, Jaimie T; Lee, W P Andrew; Brandacher, Gerald

    2015-02-01

    Reconstructive transplantation has become a viable option to restore form and function after devastating tissue loss. Functional recovery is a key determinant of overall success and critically depends on the quality and pace of nerve regeneration. Several molecular and cell-based therapies have been postulated and tested in pre-clinical animal models to enhance nerve regeneration. Schwann cells remain the mainstay of research focus providing neurotrophic support and signaling cues for regenerating axons. Alternative cell sources such as mesenchymal stem cells and adipose-derived stromal cells have also been tested in pre-clinical animal models and in clinical trials due to their relative ease of harvest, rapid expansion in vitro, minimal immunogenicity, and capacity to integrate and survive within host tissues, thereby overcoming many of the challenges faced by culturing of human Schwann cells and nerve allografting. Induced pluripotent stem cell-derived Schwann cells are of particular interest since they can provide abundant, patient-specific autologous Schwann cells. The majority of experimental evidence on cell-based therapies, however, has been generated using stem cell-seeded nerve guides that were developed to enhance nerve regeneration across "gaps" in neural repair. Although primary end-to-end repair is the preferred method of neurorrhaphy in reconstructive transplantation, mechanistic studies elucidating the principles of cell-based therapies from nerve guidance conduits will form the foundation of further research employing stem cells in end-to-end repair of donor and recipient nerves. This review presents key components of nerve regeneration in reconstructive transplantation and highlights the pre-clinical studies that utilize stem cells to enhance nerve regeneration.

  11. Patterned substrates and methods for nerve regeneration

    DOEpatents

    Mallapragada, Surya K.; Heath, Carole; Shanks, Howard; Miller, Cheryl A.; Jeftinija, Srdija

    2004-01-13

    Micropatterned substrates and methods for fabrication of artificial nerve regeneration conduits and methods for regenerating nerves are provided. Guidance compounds or cells are seeded in grooves formed on the patterned substrate. The substrates may also be provided with electrodes to provide electrical guidance cues to the regenerating nerve. The micropatterned substrates give physical, chemical, cellular and/or electrical guidance cues to promote nerve regeneration at the cellular level.

  12. An anatomical study of porcine peripheral nerve and its potential use in nerve tissue engineering.

    PubMed

    Zilic, Leyla; Garner, Philippa E; Yu, Tong; Roman, Sabiniano; Haycock, John W; Wilshaw, Stacy-Paul

    2015-09-01

    Current nerve tissue engineering applications are adopting xenogeneic nerve tissue as potential nerve grafts to help aid nerve regeneration. However, there is little literature that describes the exact location, anatomy and physiology of these nerves to highlight their potential as a donor graft. The aim of this study was to identify and characterise the structural and extracellular matrix (ECM) components of porcine peripheral nerves in the hind leg. Methods included the dissection of porcine nerves, localisation, characterisation and quantification of the ECM components and identification of nerve cells. Results showed a noticeable variance between porcine and rat nerve (a commonly studied species) in terms of fascicle number. The study also revealed that when porcine peripheral nerves branch, a decrease in fascicle number and size was evident. Porcine ECM and nerve fascicles were found to be predominately comprised of collagen together with glycosaminoglycans, laminin and fibronectin. Immunolabelling for nerve growth factor receptor p75 also revealed the localisation of Schwann cells around and inside the fascicles. In conclusion, it is shown that porcine peripheral nerves possess a microstructure similar to that found in rat, and is not dissimilar to human. This finding could extend to the suggestion that due to the similarities in anatomy to human nerve, porcine nerves may have utility as a nerve graft providing guidance and support to regenerating axons.

  13. Routine exposure of recurrent laryngeal nerve in thyroid surgery can prevent nerve injury★

    PubMed Central

    Shen, Chenling; Xiang, Mingliang; Wu, Hao; Ma, Yan; Chen, Li; Cheng, Lan

    2013-01-01

    To determine the value of dissecting the recurrent laryngeal nerve during thyroid surgery with respect to preventing recurrent laryngeal nerve injury, we retrospectively analyzed clinical data from 5 344 patients undergoing thyroidectomy. Among these cases, 548 underwent dissection of the recurrent laryngeal nerve, while 4 796 did not. There were 12 cases of recurrent laryngeal nerve injury following recurrent laryngeal nerve dissection (injury rate of 2.2%) and 512 cases of recurrent laryngeal nerve injury in those not undergoing nerve dissection (injury rate of 10.7%). This difference remained statistically significant between the two groups in terms of type of thyroid disease, type of surgery, and number of surgeries. Among the 548 cases undergoing recurrent laryngeal nerve dissection, 128 developed anatomical variations of the recurrent laryngeal nerve (incidence rate of 23.4%), but no recurrent laryngeal nerve injury was found. In addition, the incidence of recurrent laryngeal nerve injury was significantly lower in patients with the inferior parathyroid gland and middle thyroid veins used as landmarks for locating the recurrent laryngeal nerve compared with those with the entry of the recurrent laryngeal nerve into the larynx as a landmark. These findings indicate that anatomical variations of the recurrent laryngeal nerve are common, and that dissecting the recurrent laryngeal nerve during thyroid surgery is an effective means of preventing nerve injury. PMID:25206452

  14. [Transformation of trigeminal nerve tumor into malignant peripheral nerve sheath tumor (MPNST)].

    PubMed

    Nenashev, E A; Cherekaev, V A; Kadasheva, A B; Kozlov, A V; Rotin, D L; Stepanian, M A

    2012-01-01

    Malignant peripheral nerve sheath tumor (MPNST) is a rare entity with only 18 cases of trigeminal nerve MPNST described by now and only one report of malignant transformation of trigeminal nerve tumor into MPNST published up to date. One more case of malignant transformation of trigeminal nerve (1st division) tumor into MPNST is demonstrated.

  15. Simultaneous paresthesia of the lingual nerve and inferior alveolar nerve caused by a radicular cyst.

    PubMed

    Hamada, Yoshiki; Yamada, Hiroyuki; Hamada, Akiko; Kondoh, Toshirou; Suzuki, Mami; Noguchi, Kazuhide; Ito, Ko; Seto, Kanichi

    2005-10-01

    The inferior alveolar nerve is sometimes affected by periapical pathoses and mandibular cysts. However, mandibular intraosseous lesions have not been reported to disturb the lingual nerve. A case of simultaneous paresthesia of the right lingual nerve and the right inferior alveolar nerve is presented. The possible mechanisms of this extremely uncommon condition are discussed.

  16. An anatomical study of porcine peripheral nerve and its potential use in nerve tissue engineering

    PubMed Central

    Zilic, Leyla; Garner, Philippa E; Yu, Tong; Roman, Sabiniano; Haycock, John W; Wilshaw, Stacy-Paul

    2015-01-01

    Current nerve tissue engineering applications are adopting xenogeneic nerve tissue as potential nerve grafts to help aid nerve regeneration. However, there is little literature that describes the exact location, anatomy and physiology of these nerves to highlight their potential as a donor graft. The aim of this study was to identify and characterise the structural and extracellular matrix (ECM) components of porcine peripheral nerves in the hind leg. Methods included the dissection of porcine nerves, localisation, characterisation and quantification of the ECM components and identification of nerve cells. Results showed a noticeable variance between porcine and rat nerve (a commonly studied species) in terms of fascicle number. The study also revealed that when porcine peripheral nerves branch, a decrease in fascicle number and size was evident. Porcine ECM and nerve fascicles were found to be predominately comprised of collagen together with glycosaminoglycans, laminin and fibronectin. Immunolabelling for nerve growth factor receptor p75 also revealed the localisation of Schwann cells around and inside the fascicles. In conclusion, it is shown that porcine peripheral nerves possess a microstructure similar to that found in rat, and is not dissimilar to human. This finding could extend to the suggestion that due to the similarities in anatomy to human nerve, porcine nerves may have utility as a nerve graft providing guidance and support to regenerating axons. PMID:26200940

  17. Homebuyer's Guide.

    ERIC Educational Resources Information Center

    Sindt, Roger P.; Harris, Jack

    Designed to assist prospective buyers in making such important decisions as whether to buy a new or older home and within what price range, the guide provides information on the purchase process. Discussion of the purchase process covers the life-cycle costs (recurring homeownership costs that must be met every month); selection of a home;…

  18. Teachers Guide.

    ERIC Educational Resources Information Center

    Linsky, Ronald B.; Schnitger, Ronald L.

    This guide provides teachers with copies of the materials given to students participating in the oceanography program of the Orange County Floating Laboratory Program and provides information concerning colleges and universities offering courses in oceanography and marine science, source of films, and sources of publications concerning the Navy's…

  19. Persuasion Guide.

    ERIC Educational Resources Information Center

    1971

    In this teacher's guide to the textbook called "Persuasion" the emphasis is on assisting the teacher to develop in his students the skills of critical and creative thinking. Each instructional unit moves from the experience of persuasive techniques, through critical analysis, to the creative practice of the technique in question. Essays on…

  20. Instructor Guide.

    ERIC Educational Resources Information Center

    Langer, Philip; Borg, Walter R.

    This Instructor Guide is designed to acquaint the teacher educator with the Utah State University Protocol Project training materials. It deals with the protocol materials generally and with each module specifically, including the following: (a) an introduction to, and rationale for protocol modules; (b) ways of identifying specific kinds of…

  1. Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

    SciTech Connect

    Tsoumakidou, Georgia Garnon, Julien Ramamurthy, Nitin Buy, Xavier Gangi, Afshin

    2013-12-15

    Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

  2. Cranial nerve palsies in childhood

    PubMed Central

    Lyons, C J; Godoy, F; ALQahtani, E

    2015-01-01

    We review ocular motor cranial nerve palsies in childhood and highlight many of the features that differentiate these from their occurrence in adulthood. The clinical characteristics of cranial nerve palsies in childhood are affected by the child's impressive ability to repair and regenerate after injury. Thus, aberrant regeneration is very common after congenital III palsy; Duane syndrome, the result of early repair after congenital VI palsy, is invariably associated with retraction of the globe in adduction related to the innervation of the lateral rectus by the III nerve causing co-contraction in adduction. Clinical features that may be of concern in adulthood may not be relevant in childhood; whereas the presence of mydriasis in III palsy suggests a compressive aetiology in adults, this is not the case in children. However, the frequency of associated CNS abnormalities in III palsy and the risk of tumour in VI palsy can be indications for early neuroimaging depending on presenting features elicited through a careful history and clinical examination. The latter should include the neighbouring cranial nerves. We discuss the impact of our evolving knowledge of congenital cranial dysinnervation syndromes on this field. PMID:25572578

  3. Fate of combat nerve injury

    DTIC Science & Technology

    2012-11-01

    Exoskeletal Orthosis are promising, even in patients complicated by the presence of a foot drop (0/5 motor strength to the peroneal nerve), allowing them...after limb salvage. J Trauma. 2011;71:S120 S124. 32. Patzkowski JC, Blanck RV, Owens JG, et al. Can an ankle-foot orthosis change hearts and minds? J

  4. Peripheral nerve injury during anesthesia.

    PubMed

    Lieblich, S E

    1990-01-01

    A case is presented where a peripheral nerve injury occurred due to the pressure of a restraint buckle causing a postoperative motor and sensory deficit. Because these are iatrogenic injuries it is useful to review the mechanism of injury and means of prevention.

  5. Peripheral nerve injury during anesthesia.

    PubMed Central

    Lieblich, S. E.

    1990-01-01

    A case is presented where a peripheral nerve injury occurred due to the pressure of a restraint buckle causing a postoperative motor and sensory deficit. Because these are iatrogenic injuries it is useful to review the mechanism of injury and means of prevention. Images Figure 1 PMID:2096751

  6. Endoscopic-assisted infraorbital nerve release

    PubMed Central

    Sosin, Michael; De La Cruz, Carla; Christy, Michael R.

    2014-01-01

    Abstract Endoscopic-assisted techniques in plastic and craniofacial surgeries are limited. We present a patient with infraorbital nerve entrapment following traumatic facial injury that failed conservative management. Compression of the nerve was treated with an endoscopic-assisted nerve release of the surrounding soft tissue with a circumferential foraminal osteotomy. PMID:27252952

  7. Vagus nerve stimulation in clinical practice.

    PubMed

    Farmer, Adam D; Albu-Soda, Ahmed; Aziz, Qasim

    2016-11-02

    The diverse array of end organ innervations of the vagus nerve, coupled with increased basic science evidence, has led to vagus nerve stimulation becoming a management option in a number of clinical disorders. This review discusses methods of electrically stimulating the vagus nerve and its current and potential clinical uses.

  8. 21 CFR 882.5275 - Nerve cuff.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve...

  9. 21 CFR 882.5275 - Nerve cuff.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve...

  10. 21 CFR 882.5275 - Nerve cuff.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve...

  11. 21 CFR 882.5275 - Nerve cuff.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve...

  12. 21 CFR 882.5275 - Nerve cuff.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve...

  13. Trigeminal nerve: Anatomic correlation with MR imaging

    SciTech Connect

    Daniels, D.L.; Pech, P.; Pojunas, K.W.; Kilgore, D.P.; Williams, A.L.; Haughton, V.M.

    1986-06-01

    Through correlation with cryomicrotic sections, the appearance of the trigeminal nerve and its branches on magnetic resonance images is described in healthy individuals and in patients with tumors involving this nerve. Coronal images are best for defining the different parts of the nerve and for making a side-to-side comparison. Sagittal images are useful to demonstrate tumors involving the Gasserian ganglion.

  14. Extensive lipoma causing suprascapular nerve entrapment.

    PubMed

    Zvijac, John E; Sheldon, Daniel A; Schürhoff, Matthias R

    2003-03-01

    Suprascapular nerve entrapment is a frequently misdiagnosed phenomenon. In this case report, we describe a benign lipomatous tumor causing suprascapular nerve entrapment in the spinoglenoid notch, and we describe the history, clinical examination, and radiographic evaluation. Benign lipomatous tumor compressing the suprascapular nerve is mentioned in the literature, but we believe this is the first case report.

  15. Nerve Degeneration and Regeneration Associated with NF1 Tumors

    DTIC Science & Technology

    2014-09-01

    Infiltrating peripheral nerve sheath tumors (PNST) are associated with significant neurological deficits and nerve damage. An initial aim of this project is...nerve graft implanted to bridge the gap and restore nerve continuity. 15. SUBJECT TERMS peripheral nerve sheath tumor, neurofibroma, photodynamic...7 1 INTRODUCTION Infiltrating   peripheral  nerve  sheath  tumors  (PNST

  16. Sacral nerve stimulation lead implantation using the o-arm

    PubMed Central

    2013-01-01

    Background Sacral neuromodulation operations have usually been performed based on 2D fluoro images. However, sacral nerve stimulation lead implantation may be challenging when the normal anatomy is confused by obesity or congenital anomalies. Thus the surgical navigation and intraoperative imaging methods could be helpful as those same methods have proven to be feasible methods for guiding other surgical operations. Our recent knowledge about the O-arm in trauma pelvic operations encouraged us to evaluate the usefulness of O-arm guided navigation in sacral neuromodulation. Similar navigation would be useful for complex sacral nerve stimulation lead implantations. Methods In this preliminary article we report our experience of utilizing the orthopedically optimized O-arm to implant the S3 stimulation electrode in a patient. The 3D O-arm imaging was performed intraoperatively under surgical navigation control. General anesthesia was used. The obtained 3D image dataset was registered automatically into the patient’s anatomy. The stimulation needle was guided and the tined lead electrode was implanted using navigation. Results The bony sacral structures were clearly visualized. Due to automatic registration, the navigation was practicable instantly after the O-arm scanning and operation could be performed successfully under navigation control. Conclusions To our knowledge, this is the first published tined lead implantation which was guided based on the surgical navigation and intraoperative O-arm images. In this case, the applied method was useful and helped the surgeon to demarcate the region of surgical interest. The method is slightly more invasive than the formal technique but could be an option in anatomically challenging cases and reoperations. However, further evaluation with larger patient series is required before definitive recommendations can be made. PMID:24131790

  17. Mind Over Matter: The Brain's Response to Drugs. Teacher's Guide.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHHS/PHS), Rockville, MD.

    This teacher's guide aims to develop an understanding among students grades 5 through 9 of the physical reality of drug use. Contents include: (1) "Brain Anatomy"; (2) "Nerve Cells and Neurotransmission"; (3) "Effects of Drugs on the Brain"; (4) "Marijuana"; (5) "Opiates"; (6) "Inhalants"; (7) "Hallucinogens"; (8) "Steroids"; (9) "Stimulants";…

  18. Application of implantable wireless biomicrosystem for monitoring nerve impedance of rat after sciatic nerve injury.

    PubMed

    Li, Yu-Ting; Peng, Chih-Wei; Chen, Lung-Tai; Lin, Wen-Shan; Chu, Chun-Hsun; Chen, Jia-Jin Jason

    2013-01-01

    Electrical stimulation is usually applied percutaneously for facilitating peripheral nerve regeneration. However, few studies have conducted long-term monitoring of the condition of nerve regeneration. This study implements an implantable biomicrosystem for inducing pulse current for aiding nerve repair and monitoring the time-course changes of nerve impedance for assessing nerve regeneration in sciatic nerve injury rat model. For long-term implantation, a transcutaneous magnetic coupling technique is adopted for power and data transmission. For in vivo study, the implanted module was placed in the rat's abdomen and the cuff electrode was wrapped around an 8-mm sciatic nerve gap of the rat for nerve impedance measurement for 42 days. One group of animals received monophasic constant current via the cuff electrode and a second group had no stimulation between days 8-21. The nerve impedance increased to above 150% of the initial value in the nerve regeneration groups with and without stimulation whereas the group with no nerve regeneration increased to only 113% at day 42. The impedance increase in nerve regeneration groups can be observed before evident functional recovery. Also, the nerve regeneration group that received electrical stimulation had relatively higher myelinated fiber density than that of no stimulation group, 20686 versus 11417 fiber/mm (2). The developed implantable biomicrosystem is proven to be a useful experimental tool for long-term stimulation in aiding nerve fiber growth as well as impedance assessment for understanding the time-course changes of nerve regeneration.

  19. Nerve growth factor enhances sleep in rabbits.

    PubMed

    Takahashi, S; Krueger, J M

    1999-04-02

    Nerve growth factor (NGF) elicits rapid-eye-movement sleep (REMS) in cats. Removal of NGF receptor-positive cholinergic basal forebrain neurons inhibits REMS in rats. The aim of the present study was to determine the effects of NGF on sleep and brain temperature (Tbr) in rabbits. Male rabbits were implanted with electroencephalograph (EEG) electrodes, a brain thermistor and an intraventricular (i.c.v.) guide cannula. Rabbits received human beta-NGF i.c.v. (0.01, 0.1, 1.0 or 10 microg] and on a separate day, 25 microl pyrogen-free saline i.c.v. as control. EEG and Tbr were recorded for 23 h after injections. The highest two doses of NGF increased both non-REMS and REMS across the 23-h recording period. REMS was enhanced dose-dependently. Tbr was not affected by any dose of NGF. These results suggest that NGF is involved in both REMS and non-REMS regulation.

  20. Suprascapular Nerve Pathology: A Review of the Literature

    PubMed Central

    Kostretzis, Lazaros; Theodoroudis, Ioannis; Boutsiadis, Achilleas; Papadakis, Nikolaos; Papadopoulos, Pericles

    2017-01-01

    Background: Suprascapular nerve pathology is a rare diagnosis that is increasingly gaining popularity among the conditions that cause shoulder pain and dysfunction. The suprascapular nerve passes through several osseoligamentous structures and can be compressed in several locations. Methods: A thorough literature search was performed using online available databases in order to carefully define the pathophysiology and to guide diagnosis and treatment. Results: Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. Although the incidence and prevalence of the condition remain unknown, it is highly diagnosed in specific groups (overhead athletes, patients with a massive rotator cuff tear) probably due to higher interest. The location and the etiology of the compression are those that define the treatment modality. Conclusion: Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. The purpose of this article is to describe the anatomy of the suprascapular nerve, to define the pathophysiology of suprascapular neuropathy and to present methodically the current diagnostic and treatment strategies.

  1. Nerve agent detection using networks of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Novak, J. P.; Snow, E. S.; Houser, E. J.; Park, D.; Stepnowski, J. L.; McGill, R. A.

    2003-11-01

    We report the use of carbon nanotubes as a sensor for chemical nerve agents. Thin-film transistors constructed from random networks of single-walled carbon nanotubes were used to detect dimethyl methylphosphonate (DMMP), a simulant for the nerve agent sarin. These sensors are reversible and capable of detecting DMMP at sub-ppb concentration levels, and they are intrinsically selective against interferent signals from hydrocarbon vapors and humidity. We provide additional chemical specificity by the use of filters coated with chemoselective polymer films. These results indicate that the electronic detection of sub-ppb concentrations of nerve agents and potentially other chemical warfare agents is possible with simple-to-fabricate carbon nanotube devices.

  2. Pharmacology of airway afferent nerve activity

    PubMed Central

    Undem, Bradley J; Carr, Michael J

    2001-01-01

    Afferent nerves in the airways serve to regulate breathing pattern, cough, and airway autonomic neural tone. Pharmacologic agents that influence afferent nerve activity can be subclassified into compounds that modulate activity by indirect means (e.g. bronchial smooth muscle spasmogens) and those that act directly on the nerves. Directly acting agents affect afferent nerve activity by interacting with various ion channels and receptors within the membrane of the afferent terminals. Whether by direct or indirect means, most compounds that enter the airspace will modify afferent nerve activity, and through this action alter airway physiology. PMID:11686889

  3. Morphological studies of the vestibular nerve

    NASA Technical Reports Server (NTRS)

    Bergstroem, B.

    1973-01-01

    The anatomy of the intratemporal part of the vestibular nerve in man, and the possible age related degenerative changes in the nerve were studied. The form and structure of the vestibular ganglion was studied with the light microscope. A numerical analysis of the vestibular nerve, and caliber spectra of the myelinated fibers in the vestibular nerve branches were studied in individuals of varying ages. It was found that the peripheral endings of the vestibular nerve form a complicated pattern inside the vestibular sensory epithelia. A detailed description of the sensory cells and their surface organelles is included.

  4. Cranial nerves XIII and XIV: nerves in the shadows

    PubMed Central

    Bordoni, Bruno; Zanier, Emiliano

    2013-01-01

    It has been known for over a century that these cranial nerves exist, and that they are not typographical errors nor a sensational event reported in the medical literature. A number of scientific articles on anatomy highlight how textbooks on descriptive anatomy do not always consider variables such as differences related to the geographical areas where people live, and these differences do exist. This is an important concept not only for surgeons, but also for all medical professionals who use manual techniques when treating their patients, ie, osteopaths, chiropractors, physiotherapists, and other manual therapists. This paper highlights the latest developments regarding these cranial nerves, offering at the same time some ideas for further reflection when looking at clinical scenarios that appear to bear little relationship to each other. Inclusion of these concepts in everyday anamnesis is encouraged. PMID:23516138

  5. The efficacy of combined regional nerve blocks in awake orotracheal fiberoptic intubation

    PubMed Central

    Chatrath, Veena; Sharan, Radhe; Jain, Payal; Bala, Anju; Ranjana; Sudha

    2016-01-01

    Aims of Study: To evaluate the efficacy, hemodynamic changes, and patient comfort during awake fiberoptic intubation done under combined regional blocks. Materials and Methods: In the present observational study, 50 patients of American Society of Anesthesiologists ( ASA) Grade I–II, Mallampati Grade I–IV were given nerve blocks - bilateral glossopharyngeal nerve block, bilateral superior laryngeal nerve block, and recurrent laryngeal nerve block before awake fiberoptic intubation using 2% lidocaine. Results: Procedure was associated with minimal increases in hemodynamic parameters during the procedure and until 3 min after it. Most of the intubations were being carried out within 3 min. Patient comfort was satisfactory with 90% of patients having favorable grades. Discussion: The most common cause of mortality and serious morbidity due to anesthesia is from airway problems. One-third of all anesthetic deaths are due to failure to intubate and ventilate. Awake flexible fiberoptic intubation under local anesthesia is now an accepted technique for managing such situations. In awake patient's anatomy, muscle tone, airway protection, and ventilation are preserved, but it is essential to sufficiently anesthetize the upper airway before the performance of awake fiberoptic bronchoscope-guided intubation to ensure patient comfort and cooperation for which in our study we used the nerve block technique. Conclusion: A properly performed technique of awake fiberoptic intubation done under combined regional nerve blocks provides good intubating conditions, patient comfort and safety and results in minimal hemodynamic changes. PMID:27212757

  6. Experimental Polymer Mechanochemistry and its Interpretational Frameworks.

    PubMed

    Akbulatov, Sergey; Boulatov, Roman

    2017-03-03

    Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non-equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self-strengthening and stress-reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose

  7. 'Nerves': folk idiom for anxiety and depression?

    PubMed

    Nations, M K; Camino, L A; Walker, F B

    1988-01-01

    This study suggests that 'nerves' as presented in a primary care clinic is a lay idiom for emotional distress and documents a relationship between the folk ailment 'nerves' and anxiety and depression. One hundred and forty-nine patients at a Virginia clinic were studied, 47 with 'nerves', and 102 controls. Testing with the General Health Questionnaire (GHQ) and the Beck Depression Inventory (BDI) showed 'nerves' patients to be more anxious and depressed than controls. 'Nerves' patients had a mean GHQ score of 13.0 compared to 5.8 for controls (P less than 0.0001) and a BDI score of 7.6 compared to 2.5 for controls (P less than 0.0001). Testing with the Holmes-Rahe Social Readjustment Rating Scale showed 'nerves' patients to suffer more recent life stresses than controls: 'nerves' patients had a mean score of 187.1 compared to 119.3 for controls (P less than 0.05). 'Nerves' patients had somatic symptoms including gastrointestinal disturbances, headaches and shaking. 'Nerves' is most common among women and housewives, and is often attributed to misfortune and tragedy. The ethnomedical illness 'nerves' encompasses a rich array of cultural meanings reflecting the lifestyle and worldview of its sufferers. Despite its chronic debilitating nature, it is rarely recognized by physicians; it is, however, treated by alternative healers. Clinical implications are discussed and recommendations advanced, among them that physicians work with such healers in the recognition and treatment of 'nerves'.

  8. Vagus nerve stimulation regulates hemostasis in swine.

    PubMed

    Czura, Christopher J; Schultz, Arthur; Kaipel, Martin; Khadem, Anna; Huston, Jared M; Pavlov, Valentin A; Redl, Heinz; Tracey, Kevin J

    2010-06-01

    The central nervous system regulates peripheral immune responses via the vagus nerve, the primary neural component of the cholinergic anti-inflammatory pathway. Electrical stimulation of the vagus nerve suppresses proinflammatory cytokine release in response to endotoxin, I/R injury, and hypovolemic shock and protects against lethal hypotension. To determine the effect of vagus nerve stimulation on coagulation pathways, anesthetized pigs were subjected to partial ear resection before and after electrical vagus nerve stimulation. We observed that electrical vagus nerve stimulation significantly decreased bleeding time (pre-electrical vagus nerve stimulation = 1033 +/- 210 s versus post-electrical vagus nerve stimulation = 585 +/- 111 s; P < 0.05) and total blood loss (pre-electrical vagus nerve stimulation = 48.4 +/- 6.8 mL versus post-electrical vagus nerve stimulation = 26.3 +/- 6.7 mL; P < 0.05). Reduced bleeding time after vagus nerve stimulation was independent of changes in heart rate or blood pressure and correlated with increased thrombin/antithrombin III complex generation in shed blood. These data indicate that electrical stimulation of the vagus nerve attenuates peripheral hemorrhage in a porcine model of soft tissue injury and that this protective effect is associated with increased coagulation factor activity.

  9. Parotid lymphangioma associated with facial nerve paralysis.

    PubMed

    Imaizumi, Mitsuyoshi; Tani, Akiko; Ogawa, Hiroshi; Omori, Koichi

    2014-10-01

    Parotid lymphangioma is a relatively rare disease that is usually detected in infancy or early childhood, and which has typical features. Clinical reports of facial nerve paralysis caused by lymphangioma, however, are very rare. Usually, facial nerve paralysis in a child suggests malignancy. Here we report a very rare case of parotid lymphangioma associated with facial nerve paralysis. A 7-year-old boy was admitted to hospital with a rapidly enlarging mass in the left parotid region. Left peripheral-type facial nerve paralysis was also noted. Computed tomography and magnetic resonance imaging also revealed multiple cystic lesions. Open biopsy was undertaken in order to investigate the cause of the facial nerve paralysis. The histopathological findings of the excised tumor were consistent with lymphangioma. Prednisone (40 mg/day) was given in a tapering dose schedule. Facial nerve paralysis was completely cured 1 month after treatment. There has been no recurrent facial nerve paralysis for eight years.

  10. Microsurgical anatomy of the trigeminal nerve.

    PubMed

    Joo, Wonil; Yoshioka, Fumitaka; Funaki, Takeshi; Mizokami, Koji; Rhoton, Albert L

    2014-01-01

    The objective of this study is to review surgical anatomy of the trigeminal nerve. We also demonstrate some pictures involving the trigeminal nerve and its surrounding connective and neurovascular structures. Ten adult cadaveric heads were studied, using a magnification ranging from 3× to 40×, after perfusion of the arteries and veins with colored latex. The trigeminal nerve is the largest and most complex of the cranial nerves. It serves as a major conduit of sensory input from the face and provides motor innervation to the muscles of mastication. Because of its size and complexity, it is essential to have thorough knowledge of the nerve before diagnoses and treatment of the pathologic processes in the orofacial, temporomandibular, infratemporal, and pterygopalatine areas. The trigeminal nerve is encountered with imaging or surgery of the skull base surgery. Thus, a comprehensive knowledge of the anatomy of the trigeminal nerve is crucial for performing the surgical procedures without significant complication.

  11. Interpretations of Polymer-Polymer Miscibility.

    ERIC Educational Resources Information Center

    Olabisi, Olagoke

    1981-01-01

    Discusses various aspects of polymeric mixtures, mixtures of structurally different homopolymers, copolymers, terpolymers, and the like. Defines concepts of polymer-polymer miscibility from practical and theoretical viewpoints, and ways of predicting such miscibility. (JN)

  12. Tapered Bottlebrush Polymers: A New Polymer Architecture

    DTIC Science & Technology

    2015-07-30

    length of the backbone polymer . This type of covalent, cone- shaped polymer may have applications in supersoft elastomeric materials and as...rate of polymerization must be as high as possible for the synthesis of precise tapered bottlebrush polymers . An example of the kinetics data obtained... polymers with anchor group 1 allow for faster polymerization . MM Name k p (10 -3 L * mol -1 * s -1 ) t1/2 (s) krel 1S 3k 11 ± 2 68 ± 20

  13. Selective Guide to Literature on Chemical Engineering. Engineering Literature Guides, Number 9.

    ERIC Educational Resources Information Center

    Rousseau, Rosemary, Comp.

    The material in this guide covers areas important to the chemical industries. Topics such as heat and mass transfer, plastics, polymers, fluid flow, and process engineering are included. This document is a survey of information sources in chemical engineering and is intended to identify those core resources which can help engineers and librarians…

  14. Exogenous nerve growth factor protects the hypoglossal nerve against crush injury

    PubMed Central

    Fan, Li-yuan; Wang, Zhong-chao; Wang, Pin; Lan, Yu-yan; Tu, Ling

    2015-01-01

    Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase (MAPK) pathway, but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear. Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury, but there has been little research focusing on the hypoglossal nerve injury and repair. In this study, we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days. p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury; exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus. Under transmission electron microscopy, we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury. Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury. PMID:26889186

  15. Vascularized Nerve Grafts and Vascularized Fascia for Upper Extremity Nerve Reconstruction

    PubMed Central

    Kostopoulos, Vasileios K.

    2009-01-01

    Since 1976, experimental and clinical studies have suggested the superiority of vascularized nerve grafts. In this study, a 27-year experience of the senior author is presented regarding vascularized nerve grafts and fascia for complex upper extremity nerve reconstruction. The factors influencing outcomes as well as a comparison with conventional nerve grafts is presented. Since 1981, 21 vascularized nerve grafts, other than vascularized ulnar nerve, were used for reconstruction of nerve injuries in the upper extremity. Indications were prolonged denervation time, failure of the previously used conventional nerve grafts, and excessive scar in the recipient site. Injury was in the hand/wrist area (n = 5), in the forearm (n = 4), in the elbow (n = 2), in the arm (n = 4), or in the plexus (n = 6). Vascularized sural (n = 9), saphenous (n = 8), superficial radial (n = 3), and peroneal (superficial and deep) nerves were used. The mean follow-up was 31.4 months. Vascularized nerve grafts for upper extremity injuries provided good to excellent sensory return in severely scarred upper extremities in patients in whom conventional nerve grafts had failed. They have also provided relief of causalgia after painful neuroma resection and motor function recovery in selective cases even for above the elbow injuries. Small diameter vascularized nerve grafts should be considered for bridging long nerve gaps in regions of excessive scar or for reconstructions where conventional nerve grafts have failed. PMID:19381727

  16. Pleiotrophin and peripheral nerve injury.

    PubMed

    Jin, Li; Jianghai, Chen; Juan, Liu; Hao, Kang

    2009-10-01

    The proto-oncogene pleiotrophin, discovered in 1989, was considered as a multifunctional growth factor, which played an important role in tumor occurrence, development, and central nervous system. The latest research showed that pleiotrophin signal pathway probably participated in neural repair after peripheral nerve injury, especially in the following critical points, such as the protection of spinal cord neuron, the promotion of the speed of neuron axon regeneration, the guidance of neuron axon regeneration, skeleton muscle reinnervation, and so on. It potentially plays a key role in the guidance of neural axon regeneration in peripheral nervous system and muscle reinnervation. With the deepening of related researches, pleiotrophin gene would become a controllable target for improving the repairing effect of peripheral nerve injury and reconstruction of the neuromuscular junction.

  17. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2015-10-01

    approach with an acellular nerve allograft to be equivalent to standard autograft repair in rodent models. An ongoing large animal validation study...the animal studies in Aim 2. The anatomy of HAM is shown pictorially in Figure 7. In vivo, the epithelial layer is in contact with the amniotic...AxoGuard and Oasis SIS products are manufactured by Cook Medical. AxoGuard is simply a multi-layered SIS product. Given that the large animal studies with

  18. Large Extremity Peripheral Nerve Repair

    DTIC Science & Technology

    2015-10-01

    in rodent models. An ongoing large animal validation study will pave the way for human studies of this technology. 15. SUBJECT TERMS 16. SECURITY...to be clinically acceptable for use in the animal studies in Aim 2. The anatomy of HAM is shown pictorially in Figure 7. In vivo, the epithelial... animal studies with large caliber nerves in Aim 3 will use AxoGuard we feel that the single layer SIS material is totally appropriate for these small

  19. Nanohelices from planar polymer self-assembled in carbon nanotubes

    PubMed Central

    Fu, Hongjin; Xu, Shuqiong; Li, Yunfang

    2016-01-01

    The polymer possessing with planar structure can be activated and guided to encapsulate the inner space of SWNT and form a helix through van der Waals interaction and the π-π stacking effect between the polymer and the inner surface of SWNT. The SWNT size, the nanostructure and flexibility of polymer chain are all determine the final structures. The basic interaction between the polymer and the nanotubes is investigated, and the condition and mechanism of the helix-forming are explained particularly. Hybrid polymers improve the ability of the helix formation. This study provides scientific basis for fabricating helical polymers encapsulated in SWNTs and eventually on their applications in various areas. PMID:27440493

  20. Controlling Molecular Ordering in Solution-State Conjugated Polymers

    SciTech Connect

    Zhu, Jiahua; Han, Youngkyu; Kumar, Rajeev; Hong, Kunlun; Bonnesen, Peter V.; Sumpter, Bobby G.; Smith, Gregory Scott; Ivanov, Ilia N.; Do, Changwoo

    2015-07-17

    Rationally encoding molecular interactions that can control the assembly structure and functional expression in solution of conjugated polymers holds great potential for enabling optimal organic optoelectronic and sensory materials. In this work, we show that thermally-controlled and surfactant-guided assembly of water-soluble conjugated polymers in aqueous solution is a simple and effective strategy to generate optoelectronic materials with desired molecular ordering. We have studied a conjugated polymer consisting of a hydrophobic thiophene backbone and hydrophilic, thermo-responsive ethylene oxide side groups, which shows a step-wise, multi-dimensional assembly in water. By incorporating the polymer into phase-segregated domains of an amphiphilic surfactant in solution, we demonstrate that both chain conformation and degree of molecular ordering of the conjugated polymer can be tuned in hexagonal, micellar and lamellar phases of the surfactant solution. The controlled molecular ordering in conjugated polymer assembly is demonstrated as a key factor determining the electronic interaction and optical function.

  1. The behavior of neuronal cells on tendon-derived collagen sheets as potential substrates for nerve regeneration.

    PubMed

    Alberti, Kyle A; Hopkins, Amy M; Tang-Schomer, Min D; Kaplan, David L; Xu, Qiaobing

    2014-04-01

    Peripheral nervous system injuries result in a decreased quality of life, and generally require surgical intervention for repair. Currently, the gold standard of nerve autografting, based on the use of host tissue such as sensory nerves is suboptimal as it results in donor-site loss of function and requires a secondary surgery. Nerve guidance conduits fabricated from natural polymers such as collagen are a common alternative to bridge nerve defects. In the present work, tendon sections derived through a process named bioskiving were studied for their potential for use as a substrate to fabricate nerve guidance conduits. We show that cells such as rat Schwann cells adhere, proliferate, and align along the fibrous tendon substrate which has been shown to result in a more mature phenotype. Additionally we demonstrate that chick dorsal root ganglia explants cultured on the tendon grow to similar lengths compared to dorsal root ganglia cultured on collagen gels, but also grow in a more oriented manner on the tendon sections. These results show that tendon sections produced through bioskiving can support directional nerve growth and may be of use as a substrate for the fabrication of nerve guidance conduits.

  2. Transfer of the extensor indicis proprius branch of posterior interosseous nerve to reconstruct ulnar nerve and median nerve injured proximally: an anatomical study

    PubMed Central

    Wang, Pei-ji; Zhang, Yong; Zhao, Jia-ju; Zhou, Ju-pu; Zuo, Zhi-cheng; Wu, Bing-bing

    2017-01-01

    Proximal or middle lesions of the ulnar or median nerves are responsible for extensive loss of hand motor function. This occurs even when the most meticulous microsurgical techniques or nerve grafts are used. Previous studies had proposed that nerve transfer was more effective than nerve grafting for nerve repair. Our hypothesis is that transfer of the posterior interosseous nerve, which contains mainly motor fibers, to the ulnar or median nerve can innervate the intrinsic muscles of hands. The present study sought to investigate the feasibility of reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve by transferring the extensor indicis proprius branch of the posterior interosseous nerve obtained from adult cadavers. The results suggested that the extensor indicis proprius branch of the posterior interosseous nerve had approximately similar diameters and number of fascicles and myelinated nerve fibers to those of the deep branch of ulnar nerve and the thenar branch of the median nerve. These confirm the feasibility of extensor indicis proprius branch of posterior interosseous nerve transfer for reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve. This procedure could be a novel and effective method for the functional recovery of the intrinsic muscles of hands after ulnar nerve or median nerve injury. PMID:28250760

  3. Bio-inspired tactile sensor with arrayed structures based on electroactive polymers

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Sato, Hiroshi; Taya, Minoru

    2009-03-01

    We reported some work on flexible tactile sensors based on Flemion ionic polymer metal composites previously. In this work, we compared the signals in both voltage and current with the signals obtained from a giant nerve fiber reported previously by other researchers. We found some similarities between the artificial tactile sensor and the nerve fiber, in both of which ionic movement play a very important role. This bio-inspired Flemion based ionic polymer metal composites would be a good candidate for bio-related sensors especially for prosthetic limb socket interface applications.

  4. Microsurgical anatomy of the ocular motor nerves.

    PubMed

    Zhang, Yi; Liu, Hao; Liu, En-Zhong; Lin, You-Zhi; Zhao, Shi-Guang; Jing, Guo-Hua

    2010-08-01

    This study was designed to provide anatomic data to help surgeons avoid damage to the ocular motor nerves during intraorbital operations. The microsurgical anatomy of the ocular motor nerves was studied in 50 adult cadaveric heads (100 orbits). Dissections were performed with a microscope. The nerves were exposed and the neural and muscular relationships of each portion of the nerve were examined and measured. The superior division of the oculomotor nerve coursed between the optic nerve and the superior rectus muscle after it left the annular tendon, and its branches entered into the superior rectus muscle and levator muscle. A mean of five fibers (range 3-7) innervated the superior rectus muscle, and a mean of one fiber (range 1-2) followed a medial direction (84%) or went straight through the superior rectus muscle (16%). The inferior division of the oculomotor nerve branched into the medial rectus, inferior rectus and inferior oblique muscles. The trochlear nerve ended on the orbital side of the posterior one-third of the superior oblique muscle in 76 specimens. The abducens nerve ended on the posterior one-third of the lateral rectus muscle in 86 specimens. If the belly of the lateral rectus muscle was divided into three superior-inferior parts, the nerve commonly entered into the middle one-third in 74 specimens. Based on the observed data, microanatomical relationships of the orbital contents were revised.

  5. Inferior alveolar nerve block: Alternative technique

    PubMed Central

    Thangavelu, K.; Kannan, R.; Kumar, N. Senthil

    2012-01-01

    Background: Inferior alveolar nerve block (IANB) is a technique of dental anesthesia, used to produce anesthesia of the mandibular teeth, gingivae of the mandible and lower lip. The conventional IANB is the most commonly used the nerve block technique for achieving local anesthesia for mandibular surgical procedures. In certain cases, however, this nerve block fails, even when performed by the most experienced clinician. Therefore, it would be advantageous to find an alternative simple technique. Aim and Objective: The objective of this study is to find an alternative inferior alveolar nerve block that has a higher success rate than other routine techniques. To this purpose, a simple painless inferior alveolar nerve block was designed to anesthetize the inferior alveolar nerve. Materials and Methods: This study was conducted in Oral surgery department of Vinayaka Mission's dental college Salem from May 2009 to May 2011. Five hundred patients between the age of 20 years and 65 years who required extraction of teeth in mandible were included in the study. Out of 500 patients 270 were males and 230 were females. The effectiveness of the IANB was evaluated by using a sharp dental explorer in the regions innervated by the inferior alveolar, lingual, and buccal nerves after 3, 5, and 7 min, respectively. Conclusion: This study concludes that inferior alveolar nerve block is an appropriate alternative nerve block to anesthetize inferior alveolar nerve due to its several advantages. PMID:25885503

  6. Effects of melatonin on peripheral nerve regeneration.

    PubMed

    Turgut, Mehmet; Kaplan, Süleyman

    2011-05-01

    In the available literature, there are thousands of studies on peripheral nerve regeneration using many nerves of several animals at different ages with various types of lesions and different methods of evaluation at certain time of follow-up. Despite many experimental data and clinical observations, there is still no ideal treatment method enhancing peripheral nerve regeneration. In clinical practice, various types of surgical nerve repair techniques do not frequently result in complete recovery due to neuroma formation, lipid peroxidative damage, ischemia and other factors. Recently, a number of neuroscientists demonstrated that pineal neurohormone melatonin (MLT) has an effect on the morphologic features of the nerve tissue, suggesting its neuroprotective, free radical scavenging, antioxidative, and analgesic effects in degenerative diseases of peripheral nerves. At present, it is widely accepted that MLT has a useful effect on axon length and sprouting after traumatic events to peripheral nerves. Our studies using various experimental injury models clearly suggest positive effects of MLT on the number of axons, thickness of myelin sheath by inhibition of collagen accumulation and neuroma formation following traumatic events to peripheral nerves, myelination of developing peripheral nerve after intrauterine ethanol exposure. Nevertheless, further experimental and randomized controlled clinical studies are vital to identify the clinical use of MLT hormone. This is an overview of recent patents and current literature in terms of the effects of MLT on peripheral nerve regeneration based on a critical analysis of electrophysiological, biochemical and light and electron microscopic findings, in addition to functional observations.

  7. From commodity polymers to functional polymers.

    PubMed

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-04-08

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications.

  8. From Commodity Polymers to Functional Polymers

    PubMed Central

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  9. Diverse mechanisms for assembly of branchiomeric nerves.

    PubMed

    Cox, Jane A; Lamora, Angela; Johnson, Stephen L; Voigt, Mark M

    2011-09-15

    The formation of branchiomeric nerves (cranial nerves V, VII, IX and X) from their sensory, motor and glial components is poorly understood. The current model for cranial nerve formation is based on the Vth nerve, in which sensory afferents are formed first and must enter the hindbrain in order for the motor efferents to exit. Using transgenic zebrafish lines to discriminate between motor neurons, sensory neurons and peripheral glia, we show that this model does not apply to the remaining three branchiomeric nerves. For these nerves, the motor efferents form prior to the sensory afferents, and their pathfinding show no dependence on sensory axons, as ablation of cranial sensory neurons by ngn1 knockdown had no effect. In contrast, the sensory limbs of the IXth and Xth nerves (but not the Vth or VIIth) were misrouted in gli1 mutants, which lack hindbrain bmn, suggesting that the motor efferents are crucial for appropriate sensory axon projection in some branchiomeric nerves. For all four nerves, peripheral glia were the intermediate component added and had a critical role in nerve integrity but not in axon guidance, as foxd3 null mutants lacking peripheral glia exhibited defasciculation of gVII, gIX, and gX axons. The bmn efferents were unaffected in these mutants. These data demonstrate that multiple mechanisms underlie formation of the four branchiomeric nerves. For the Vth, sensory axons initiate nerve formation, for the VIIth the sensory and motor limbs are independent, and for the IXth/Xth the motor axons initiate formation. In all cases the glia are patterned by the initiating set of axons and are needed to maintain axon fasciculation. These results reveal that coordinated interactions between the three neural cell types in branchiomeric nerves differ according to their axial position.

  10. [Anatomical variants of the medial calcaneal nerve and the Baxter nerve in the tarsal tunnel].

    PubMed

    Martín-Oliva, X; Elgueta-Grillo, J; Veliz-Ayta, P; Orosco-Villaseñor, S; Elgueta-Grillo, M; Viladot-Perice, R

    2013-01-01

    The tarsal tunnel is composed of the posterior border of the medial malleoulus, the posterior aspect of the talus and the medial aspect of the calcaneus. The medial calcaneal nerve emerges from the posterior aspect of the posterior tibial nerve in 75% of cases and from the lateral plantar nerve in the remaining 25%. Finally, the medial calcaneal nerve ends as a single terminal branch in 79% of cases and in numerous terminal branches in the remaining 21%. To describe the anatomical variants of the posterior tibial nerve and its terminal branches. To describe the steps for tarsal tunnel release. To describe Baxter nerve release. The anatomical variants of the posterior tibial nerve and its terminal branches within the tarsal tunnel were studied. Then the Lam technique was performed; it consists of: 1) opening of the laciniate ligament, 2) opening of the fascia over the abductor hallucis muscle, 3) exoneurolysis of the posterior tibial nerve and its terminal branches, identifying the emergence and pathway of the medial calcaneal branch, the lateral plantar nerve and its Baxter nerve branch and the medial plantar nerve. Baxter nerve was found in 100% of cases. In 100% of cases in our series the nerve going to the abductor digiti minimi muscle of the foot was found; 87.5% of cases had two terminal branches. The dissections proved that a crucial step was the release of the distal tarsal tunnel.

  11. Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects

    PubMed Central

    Biazar, Esmaeil; Keshel, Saeed Heidari; Pouya, Majid; Rad, Hadi; Nava, Melody Omrani; Azarbakhsh, Mohammad; Hooshmand, Shirin

    2013-01-01

    It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were cally observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. Masson's trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cells on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects. PMID:25206536

  12. Sciatic nerve regeneration using a nerve growth factor-containing fibrin glue membrane.

    PubMed

    Ma, Shengzhong; Peng, Changliang; Wu, Shiqing; Wu, Dongjin; Gao, Chunzheng

    2013-12-25

    Our previous findings confirmed that the nerve growth factor-containing fibrin glue membrane provides a good microenvironment for peripheral nerve regeneration; however, the precise mechanism remains unclear. p75 neurotrophin receptor (p75(NTR)) plays an important role in the regulation of peripheral nerve regeneration. We hypothesized that a nerve growth factor-containing fibrin glue membrane can promote neural regeneration by up-regulating p75(NTR) expression. In this study, we used a silicon nerve conduit to bridge a 15 mm-long sciatic nerve defect and injected a mixture of nerve growth factor and fibrin glue at the anastomotic site of the nerve conduit and the sciatic nerve. Through RT-PCR and western blot analysis, nerve growth factor-containing fibrin glue membrane significantly increased p75(NTR) mRNA and protein expression in the Schwann cells at the anastomotic site, in particular at 8 weeks after injection of the nerve growth factor/fibrin glue mixture. These results indicate that nerve growth factor-containing fibrin glue membrane can promote peripheral nerve regeneration by up-regulating p75(NTR) expression in Schwann cells.

  13. Compact fluorescence and white-light imaging system for intraoperative visualization of nerves

    NASA Astrophysics Data System (ADS)

    Gray, Dan; Kim, Evgenia; Cotero, Victoria; Staudinger, Paul; Yazdanfar, Siavash; tan Hehir, Cristina

    2012-02-01

    Fluorescence image guided surgery (FIGS) allows intraoperative visualization of critical structures, with applications spanning neurology, cardiology and oncology. An unmet clinical need is prevention of iatrogenic nerve damage, a major cause of post-surgical morbidity. Here we describe the advancement of FIGS imaging hardware, coupled with a custom nerve-labeling fluorophore (GE3082), to bring FIGS nerve imaging closer to clinical translation. The instrument is comprised of a 405nm laser and a white light LED source for excitation and illumination. A single 90 gram color CCD camera is coupled to a 10mm surgical laparoscope for image acquisition. Synchronization of the light source and camera allows for simultaneous visualization of reflected white light and fluorescence using only a single camera. The imaging hardware and contrast agent were evaluated in rats during in situ surgical procedures.

  14. A compact fluorescence and white light imaging system for intraoperative visualization of nerves

    NASA Astrophysics Data System (ADS)

    Gray, Dan; Kim, Evgenia; Cotero, Victoria; Staudinger, Paul; Yazdanfar, Siavash; Tan Hehir, Cristina

    2012-03-01

    Fluorescence image guided surgery (FIGS) allows intraoperative visualization of critical structures, with applications spanning neurology, cardiology and oncology. An unmet clinical need is prevention of iatrogenic nerve damage, a major cause of post-surgical morbidity. Here we describe the advancement of FIGS imaging hardware, coupled with a custom nerve-labeling fluorophore (GE3082), to bring FIGS nerve imaging closer to clinical translation. The instrument is comprised of a 405nm laser and a white light LED source for excitation and illumination. A single 90 gram color CCD camera is coupled to a 10mm surgical laparoscope for image acquisition. Synchronization of the light source and camera allows for simultaneous visualization of reflected white light and fluorescence using only a single camera. The imaging hardware and contrast agent were evaluated in rats during in situ surgical procedures.

  15. The influence of nerve conduits diameter in motor nerve recovery after segmental nerve repair.

    PubMed

    Giusti, Guilherme; Shin, Richard H; Lee, Joo-Yup; Mattar, Tiago G; Bishop, Allen T; Shin, Alexander Y

    2014-11-01

    Many conduits have demonstrated potential to substitute nerve autografts; however, the influence of conduit inner diameter (ID) has never been studied as a separate parameter. This experimental study compared motor recovery after segmental nerve repair with two different ID collagen conduits: 1.5 and 2.0 mm. In addition, the conduits were analyzed in vitro to determine the variations of ID before and after hydration. Thirty rats were divided into three groups: 2.0 mm ID, 1.5 mm ID, and a control group autograft. After 12 weeks, the 1.5 mm ID group demonstrated significant increase in force (P < 0.0001) and weight (P < 0.0001) of the tibialis anterior muscle and better histomorphometry results of the peroneal nerve (P < 0.05) compared to 2.0 mm ID group; nevertheless, autograft results outperformed both conduits (P < 0.0001). Conduits ID were somewhat smaller than advertised, measuring 1.59 ± 0.03 mm and 1.25 ± 0.0 mm. Only the larger conduit showed a 6% increase in ID after hydration, changing to 1.69 ± 0.02 mm. Although autografts perform best, an improvement in motor recovery can be achieved with collagen conduits when a better size match conduit is being used. Minimal changes in collagen conduits ID can be expected after implantation.

  16. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  17. Ultrasound-Guided Suprainguinal Fascia Iliaca Technique Provides Benefit as an Analgesic Adjunct for Patients Undergoing Total Hip Arthroplasty.

    PubMed

    Bullock, W Michael; Yalamuri, Suraj M; Gregory, Stephen H; Auyong, David B; Grant, Stuart A

    2017-02-01

    Analgesia after total hip arthroplasty is often accomplished by the fascia iliaca compartment block, traditionally performed below the inguinal ligament, to anesthetize both femoral and lateral femoral cutaneous nerves. The course of the lateral femoral cutaneous nerve below the inguinal ligament is variable as opposed to consistent above the inguinal ligament in the pelvis. In this case series including 5 patients, we demonstrate that an ultrasound-guided suprainguinal fascia iliaca approach would consistently anesthetize the lateral femoral cutaneous nerve along with anterior cutaneous femoral nerve branches and provide cutaneous analgesia after total hip arthroplasty, as shown by decreased opioid consumption.

  18. Imaging the Facial Nerve: A Contemporary Review

    PubMed Central

    Gupta, Sachin; Mends, Francine; Hagiwara, Mari; Fatterpekar, Girish; Roehm, Pamela C.

    2013-01-01

    Imaging plays a critical role in the evaluation of a number of facial nerve disorders. The facial nerve has a complex anatomical course; thus, a thorough understanding of the course of the facial nerve is essential to localize the sites of pathology. Facial nerve dysfunction can occur from a variety of causes, which can often be identified on imaging. Computed tomography and magnetic resonance imaging are helpful for identifying bony facial canal and soft tissue abnormalities, respectively. Ultrasound of the facial nerve has been used to predict functional outcomes in patients with Bell's palsy. More recently, diffusion tensor tractography has appeared as a new modality which allows three-dimensional display of facial nerve fibers. PMID:23766904

  19. Microsurgical anatomy of the trochlear nerve.

    PubMed

    Joo, Wonil; Rhoton, Albert L

    2015-10-01

    The trochlear nerve is the cranial nerve with the longest intracranial course, but also the thinnest. It is the only nerve that arises from the dorsal surface of the brainstem and decussates in the superior medullary velum. After leaving the dorsal surface of the brainstem, it courses anterolaterally around the lateral surface of the brainstem and then passes anteriorly just beneath the free edge of the tentorium. It passes forward to enter the cavernous sinus, traverses the superior orbital fissure and terminates in the superior oblique muscle in the orbit. Because of its small diameter and its long course, the trochlear nerve can easily be injured during surgical procedures. Therefore, precise knowledge of its surgical anatomy and its neurovascular relationships is essential for approaching and removing complex lesions of the orbit and the middle and posterior fossae safely. This review describes the microsurgical anatomy of the trochlear nerve and is illustrated with pictures involving the nerve and its surrounding connective and neurovascular structures.

  20. Magnetic resonance imaging of optic nerve

    PubMed Central

    Gala, Foram

    2015-01-01

    Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies. PMID:26752822

  1. OCDR guided laser ablation device

    DOEpatents

    Dasilva, Luiz B.; Colston, Jr., Bill W.; James, Dale L.

    2002-01-01

    A guided laser ablation device. The device includes a mulitmode laser ablation fiber that is surrounded by one or more single mode optical fibers that are used to image in the vicinity of the laser ablation area to prevent tissue damage. The laser ablation device is combined with an optical coherence domain reflectometry (OCDR) unit and with a control unit which initializes the OCDR unit and a high power laser of the ablation device. Data from the OCDR unit is analyzed by the control unit and used to control the high power laser. The OCDR images up to about 3 mm ahead of the ablation surface to enable a user to see sensitive tissue such as a nerve or artery before damaging it by the laser.

  2. Drug Delivery for Peripheral Nerve Regeneration

    DTIC Science & Technology

    2015-11-01

    hydrogels. The shortcomings of current devices in terms of burst effect , nonuniform dosage, and uneven drug delivery, necessitates a new approach to...Specific Aim 2 -- To evaluate the effectiveness of the conduit- drug delivery device to enhance nerve regeneration across a 15mm nerve gap in a rat sciatic...main tasks of Aim 1. Specific Aim 2 -- To evaluate the effectiveness of the conduit- drug delivery device to enhance nerve regeneration across a

  3. Drug Delivery for Peripheral Nerve Regeneration

    DTIC Science & Technology

    2014-09-01

    require special bridging strategies for tension-free repair. Autologous nerve grafts serve as the state-of-the-art in repairing such gaps but numerous...the regenerating nerves and can allow for tension free bridging without the need to harvest donor nerve. A number of research groups have proposed...Optimize nanoporous membrane dimensions ......................(Gale)(months 2-3) c. Optimize reservoir dimensions

  4. Stimulation of neurite outgrowth using an electrically conducting polymer

    PubMed Central

    Schmidt, Christine E.; Shastri, Venkatram R.; Vacanti, Joseph P.; Langer, Robert

    1997-01-01

    Damage to peripheral nerves often cannot be repaired by the juxtaposition of the severed nerve ends. Surgeons have typically used autologous nerve grafts, which have several drawbacks including the need for multiple surgical procedures and loss of function at the donor site. As an alternative, the use of nerve guidance channels to bridge the gap between severed nerve ends is being explored. In this paper, the electrically conductive polymer—oxidized polypyrrole (PP)—has been evaluated for use as a substrate to enhance nerve cell interactions in culture as a first step toward potentially using such polymers to stimulate in vivo nerve regeneration. Image analysis demonstrates that PC-12 cells and primary chicken sciatic nerve explants attached and extended neurites equally well on both PP films and tissue culture polystyrene in the absence of electrical stimulation. In contrast, PC-12 cells interacted poorly with indium tin oxide (ITO), poly(l-lactic acid) (PLA), and poly(lactic acid-co-glycolic acid) surfaces. However, PC-12 cells cultured on PP films and subjected to an electrical stimulus through the film showed a significant increase in neurite lengths compared with ones that were not subjected to electrical stimulation through the film and tissue culture polystyrene controls. The median neurite length for PC-12 cells grown on PP and subjected to an electrical stimulus was 18.14 μm (n = 5643) compared with 9.5 μm (n = 4440) for controls. Furthermore, animal implantation studies reveal that PP invokes little adverse tissue response compared with poly(lactic acid-co-glycolic acid). PMID:9256415

  5. NERVE AS MODEL TEMPERATURE END ORGAN

    PubMed Central

    Bernhard, C. G.; Granit, Ragnar

    1946-01-01

    Rapid local cooling of mammalian nerve sets up a discharge which is preceded by a local temperature potential, the cooled region being electronegative relative to a normal portion of the nerve. Heating the nerve locally above its normal temperature similarly makes the heated region electronegative relative to a region at normal temperature, and again a discharge is set up from the heated region. These local temperature potentials, set up by the nerve itself, are held to serve as "generator potentials" and the mechanism found is regarded as the prototype for temperature end organs. PMID:19873460

  6. Vagus nerve stimulation inhibits cortical spreading depression.

    PubMed

    Chen, Shih-Pin; Ay, Ilknur; de Morais, Andreia Lopes; Qin, Tao; Zheng, Yi; Sadeghian, Homa; Oka, Fumiaki; Simon, Bruce; Eikermann-Haerter, Katharina; Ayata, Cenk

    2016-04-01

    Vagus nerve stimulation has recently been reported to improve symptoms of migraine. Cortical spreading depression is the electrophysiological event underlying migraine aura and is a trigger for headache. We tested whether vagus nerve stimulation inhibits cortical spreading depression to explain its antimigraine effect. Unilateral vagus nerve stimulation was delivered either noninvasively through the skin or directly by electrodes placed around the nerve. Systemic physiology was monitored throughout the study. Both noninvasive transcutaneous and invasive direct vagus nerve stimulations significantly suppressed spreading depression susceptibility in the occipital cortex in rats. The electrical stimulation threshold to evoke a spreading depression was elevated by more than 2-fold, the frequency of spreading depressions during continuous topical 1 M KCl was reduced by ∼40%, and propagation speed of spreading depression was reduced by ∼15%. This effect developed within 30 minutes after vagus nerve stimulation and persisted for more than 3 hours. Noninvasive transcutaneous vagus nerve stimulation was as efficacious as direct invasive vagus nerve stimulation, and the efficacy did not differ between the ipsilateral and contralateral hemispheres. Our findings provide a potential mechanism by which vagus nerve stimulation may be efficacious in migraine and suggest that susceptibility to spreading depression is a suitable platform to optimize its efficacy.

  7. Raman microspectroscopy for visualization of peripheral nerves

    NASA Astrophysics Data System (ADS)

    Minamikawa, Takeo; Harada, Yoshinori; Koizumi, Noriaki; Takamatsu, Tetsuro

    2013-02-01

    The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery is essential for improving quality of life of patients. To preserve peripheral nerves, detection of ne peripheral nerves that cannot be identi ed by human eye or under white light imaging is necessary. In this study, we sought to provide a proof-of-principle demonstration of a label-free detection technique of peripheral nerve tissues against adjacent tissues that employs spontaneous Raman microspectroscopy. A line-illumination confocal Raman microscope was used for the experiment. A laser operating at the wavelength of 532 nm was used as an excitation laser light. We obtained Raman spectra of peripheral nerve, brous connective tissue, skeletal muscle, blood vessel, and adipose tissue of Wistar rats, and extracted speci c spectral features of peripheral nerves and adjacent tissues. By applying multivariate image analysis, peripheral nerves were clearly detected against adjacent tissues without any preprocessing neither xation nor staining. These results suggest the potential of the Raman spectroscopic observation for noninvasive and label-free nerve detection, and we expect this method could be a key technique for nerve-sparing surgery.

  8. Tissue engineered constructs for peripheral nerve surgery

    PubMed Central

    Johnson, P. J.; Wood, M. D.; Moore, A. M.; Mackinnon, S. E.

    2013-01-01

    Summary Background Tissue engineering has been defined as “an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ”. Traumatic peripheral nerve injury resulting in significant tissue loss at the zone of injury necessitates the need for a bridge or scaffold for regenerating axons from the proximal stump to reach the distal stump. Methods A review of the literature was used to provide information on the components necessary for the development of a tissue engineered peripheral nerve substitute. Then, a comprehensive review of the literature is presented composed of the studies devoted to this goal. Results Extensive research has been directed toward the development of a tissue engineered peripheral nerve substitute to act as a bridge for regenerating axons from the proximal nerve stump seeking the distal nerve. Ideally this nerve substitute would consist of a scaffold component that mimics the extracellular matrix of the peripheral nerve and a cellular component that serves to stimulate and support regenerating peripheral nerve axons. Conclusions The field of tissue engineering should consider its challenge to not only meet the autograft “gold standard” but also to understand what drives and inhibits nerve regeneration in order to surpass the results of an autograft. PMID:24385980

  9. Ventral nerve cord in Phoronopsis harmeri larvae.

    PubMed

    Temereva, Elena N

    2012-01-15

    The nervous system organization is considered a phylogenetically important character among metazoans. The phylum Phoronida is included in a supraphyletic taxon known as Lophotrochozoa. Many lophotrochozoans possess a metameric ventral nerve cord as adults or larvae. Phoronids do not exhibit external metamery either as larvae or as adults. The current study describes the ventral nerve cord in the young larva of Phoronopsis harmeri. This structure is apparent both in the serotonergic and FMRF-amidergic nervous system in young larvae. The ventral nerve cord extends from the mouth to the tentacular ridge. Both serotonergic and FMRF-amidergic components consist of two ventrolateral nerves, each with several unipolar neurons. The ventrolateral nerves connect to each other by means of thin repetitive transversal nerves ("commissures"). The abundance of neurons and nerves in the epidermis of the oral field of actinotrocha larva likely reflects the importance of this area in collection of food particles. The ventral nerve cords of the actinotrocha and the metatrochophore differ in their positions with respect to ciliated bands: the cord is located between the preoral and postoral ciliated bands in the actinotrocha but between the postoral ciliated band and telotroch in the metatrochophore. The presence of the ventral nerve cord, which contains repetitive elements (neurons and "commissures"), in the early development of P. harmeri may recapitulate some stages of nervous system development during phoronid phylogeny. The larval nervous system does not contain nervous centers under the tentacular ridge that can correlate with the catastrophic metamorphosis and unique body plan of phoronids.

  10. Nerve Transfers to Restore Shoulder Function.

    PubMed

    Leechavengvongs, Somsak; Malungpaishorpe, Kanchai; Uerpairojkit, Chairoj; Ng, Chye Yew; Witoonchart, Kiat

    2016-05-01

    The restoration of shoulder function after brachial plexus injury represents a significant challenge facing the peripheral nerve surgeons. This is owing to a combination of the complex biomechanics of the shoulder girdle, the multitude of muscles and nerves that could be potentially injured, and a limited number of donor options. In general, nerve transfer is favored over tendon transfer, because the biomechanics of the musculotendinous units are not altered. This article summarizes the surgical techniques and clinical results of nerve transfers for restoration of shoulder function.

  11. Facial Nerve Schwannoma of the Cerebellopontine Angle

    PubMed Central

    Lassaletta, Luis; Roda, José María; Frutos, Remedios; Patrón, Mercedes; Gavilán, Javier

    2002-01-01

    Facial nerve schwannomas are rare lesions that may involve any segment of the facial nerve. Because of their rarity and the lack of a consistent clinical and radiological pattern, facial nerve schwannomas located at the cerebellopontine angle (CPA) and internal auditory canal (IAC) represent a diagnostic and therapeutic challenge for clinicians. In this report, a case of a CPA/IAC facial nerve schwannoma is presented. Contemporary diagnosis and management of this rare lesion are analyzed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:17167683

  12. Normal and sonographic anatomy of selected peripheral nerves. Part III: Peripheral nerves of the lower limb.

    PubMed

    Kowalska, Berta; Sudoł-Szopińska, Iwona

    2012-06-01

    The ultrasonographic examination is currently increasingly used in imaging peripheral nerves, serving to supplement the physical examination, electromyography and magnetic resonance imaging. As in the case of other USG imaging studies, the examination of peripheral nerves is non-invasive and well-tolerated by patients. The typical ultrasonographic picture of peripheral nerves as well as the examination technique have been discussed in part I of this article series, following the example of the median nerve. Part II of the series presented the normal anatomy and the technique for examining the peripheral nerves of the upper limb. This part of the article series focuses on the anatomy and technique for examining twelve normal peripheral nerves of the lower extremity: the iliohypogastric and ilioinguinal nerves, the lateral cutaneous nerve of the thigh, the pudendal, sciatic, tibial, sural, medial plantar, lateral plantar, common peroneal, deep peroneal and superficial peroneal nerves. It includes diagrams showing the proper positioning of the sonographic probe, plus USG images of the successively discussed nerves and their surrounding structures. The ultrasonographic appearance of the peripheral nerves in the lower limb is identical to the nerves in the upper limb. However, when imaging the lower extremity, convex probes are more often utilized, to capture deeply-seated nerves. The examination technique, similarly to that used in visualizing the nerves of upper extremity, consists of locating the nerve at a characteristic anatomic reference point and tracking it using the "elevator technique". All 3 parts of the article series should serve as an introduction to a discussion of peripheral nerve pathologies, which will be presented in subsequent issues of the "Journal of Ultrasonography".

  13. Permanent nerve damage from inferior alveolar nerve blocks: a current update.

    PubMed

    Pogrel, M Anthony

    2012-10-01

    Permanent nerve involvement has been reported following inferior alveolar nerve blocks. This study provides an update on cases reported to one unit in the preceding six years. Lidocaine was associated with 25 percent of cases, articaine with 33 percent of cases, and prilocaine with 34 percent of cases. It does appear that inferior alveolar nerve blocks can cause permanent nerve damage with any local anesthetic, but the incidences may vary.

  14. Wnt-Ror signaling to SIA and SIB neurons directs anterior axon guidance and nerve ring placement in C. elegans

    PubMed Central

    Kennerdell, Jason R.; Fetter, Richard D.; Bargmann, Cornelia I.

    2009-01-01

    Summary Wnt signaling through Frizzled proteins guides posterior cells and axons in C. elegans into different spatial domains. Here we demonstrate an essential role for Wnt signaling through Ror tyrosine kinase homologs in the most prominent anterior neuropil, the nerve ring. A genetic screen uncovered cwn-2, the C. elegans homolog of Wnt5, as a regulator of nerve ring placement. In cwn-2 mutants, all neuronal structures in and around the nerve ring are shifted to an abnormal anterior position. cwn-2 is required at the time of nerve ring formation; it is expressed by cells posterior of the nerve ring, but its precise site of expression is not critical for its function. In nerve ring development, cwn-2 acts primarily through the Wnt receptor CAM-1 (Ror), together with the Frizzled protein MIG-1, with parallel roles for the Frizzled protein CFZ-2. The identification of CAM-1 as a CWN-2 receptor contrasts with CAM-1 action as a non-receptor in other C. elegans Wnt pathways. Cell-specific rescue of cam-1 and cell ablation experiments reveal a crucial role for the SIA and SIB neurons in positioning the nerve ring, linking Wnt signaling to specific cells that organize the anterior nervous system. PMID:19855022

  15. Comparison of Nerve Excitability Testing, Nerve Conduction Velocity, and Behavioral Observations for Acrylamide Induced Peripheral Neuropathy

    EPA Science Inventory

    Nerve excitability (NE) testing is a sensitive method to test for peripheral neurotoxicity in humans,and may be more sensitive than compound nerve action potential (CNAP) or nerve conduction velocity (NCV).We used acrylamide to compare the NE and CNAP/NCV methods. Behavioral test...

  16. The Cranial Nerve Skywalk: A 3D Tutorial of Cranial Nerves in a Virtual Platform

    ERIC Educational Resources Information Center

    Richardson-Hatcher, April; Hazzard, Matthew; Ramirez-Yanez, German

    2014-01-01

    Visualization of the complex courses of the cranial nerves by students in the health-related professions is challenging through either diagrams in books or plastic models in the gross laboratory. Furthermore, dissection of the cranial nerves in the gross laboratory is an extremely meticulous task. Teaching and learning the cranial nerve pathways…

  17. Lost in translation: ambiguity in nerve sheath tumor nomenclature and its resultant treatment effect.

    PubMed

    Bernthal, Nicholas M; Jones, Kevin B; Monument, Michael J; Liu, Ting; Viskochil, David; Randall, R Lor

    2013-05-08

    There is much ambiguity surrounding the diagnosis of nerve sheath tumors, including atypical neurofibroma and low-grade MPNST, and yet, the distinction between these entities designates either benign or malignant behavior and thus carries presumed profound prognostic importance that often guides treatment. This study reviews the diagnostic criteria used to designate atypical neurofibroma from low-grade MPNSTs and reviews existing literature the natural history of each of these tumors to see if the distinction is, in fact, of importance.

  18. A case report of complex auricular neuralgia treated with the great auricular nerve and facet blocks

    PubMed Central

    Eghtesadi, Marzieh; Leroux, Elizabeth; Vargas-Schaffer, Grisell

    2017-01-01

    Background The great auricular nerve is a cutaneous branch of the cervical plexus originating from the C2 and C3 spinal nerves. It innervates the skin over the external ear, the angle of the mandible and the parotid gland. It communicates with the ansa cervicalis. Great auricular neuralgia is rarely diagnosed in clinical practice and can be refractory. We present a new approach using ultrasound-guided nerve blocks. Case We present a case of a 41-year-old female with paroxysmal ear pain accompanied by dysautonomia, tingling in the tongue, dysphagia, dysarthria and abdominal symptoms. No significant findings were found on cervical and brain imaging. The patient responded partially to a great auricular nerve block. A combined approach using this block with facet block of C2 and C3 induced a more pronounced and prolonged benefit. Conclusion Great auricular neuralgia is not often encountered in practice and can be accompanied by symptoms originating from the ansa cervicalis network. A combined approach of nerve blocks can be considered in refractory cases. PMID:28255253

  19. Long-term survival and integration of transplanted engineered nervous tissue constructs promotes peripheral nerve regeneration.

    PubMed

    Huang, Jason H; Cullen, D Kacy; Browne, Kevin D; Groff, Robert; Zhang, Jun; Pfister, Bryan J; Zager, Eric L; Smith, Douglas H

    2009-07-01

    Although peripheral nerve injury is a common consequence of trauma or surgery, there are insufficient means for repair. In particular, there is a critical need for improved methods to facilitate regeneration of axons across major nerve lesions. Here, we engineered transplantable living nervous tissue constructs to provide a labeled pathway to guide host axonal regeneration. These constructs consisted of stretch-grown, longitudinally aligned living axonal tracts inserted into poly(glycolic acid) tubes. The constructs (allogenic) were transplanted to bridge an excised segment of sciatic nerve in the rat, and histological analyses were performed at 6 and 16 weeks posttransplantation to determine graft survival, integration, and host regeneration. At both time points, the transplanted constructs were found to have maintained their pretransplant geometry, with surviving clusters of graft neuronal somata at the extremities of the constructs spanned by tracts of axons. Throughout the transplanted region, there was an intertwining plexus of host and graft axons, suggesting that the transplanted axons mediated host axonal regeneration across the lesion. By 16 weeks posttransplant, extensive myelination of axons was observed throughout the transplant region. Further, graft neurons had extended axons beyond the margins of the transplanted region, penetrating into the host nerve. Notably, this survival and integration of the allogenic constructs occurred in the absence of immunosuppression therapy. These findings demonstrate the promise of living tissue-engineered axonal constructs to bridge major nerve lesions and promote host regeneration, potentially by providing axon-mediated axonal outgrowth and guidance.

  20. 3D-engineering of Cellularized Conduits for Peripheral Nerve Regeneration

    PubMed Central

    Hu, Yu; Wu, Yao; Gou, Zhiyuan; Tao, Jie; Zhang, Jiumeng; Liu, Qianqi; Kang, Tianyi; Jiang, Shu; Huang, Siqing; He, Jiankang; Chen, Shaochen; Du, Yanan; Gou, Maling

    2016-01-01

    Tissue engineered conduits have great promise for bridging peripheral nerve defects by providing physical guiding and biological cues. A flexible method for integrating support cells into a conduit with desired architectures is wanted. Here, a 3D-printing technology is adopted to prepare a bio-conduit with designer structures for peripheral nerve regeneration. This bio-conduit is consisted of a cryopolymerized gelatin methacryloyl (cryoGelMA) gel cellularized with adipose-derived stem cells (ASCs). By modeling using 3D-printed “lock and key” moulds, the cryoGelMA gel is structured into conduits with different geometries, such as the designed multichannel or bifurcating and the personalized structures. The cryoGelMA conduit is degradable and could be completely degraded in 2-4 months in vivo. The cryoGelMA scaffold supports the attachment, proliferation and survival of the seeded ASCs, and up-regulates the expression of their neurotrophic factors mRNA in vitro. After implanted in a rat model, the bio-conduit is capable of supporting the re-innervation across a 10 mm sciatic nerve gap, with results close to that of the autografts in terms of functional and histological assessments. The study describes an indirect 3D-printing technology for fabricating cellularized designer conduits for peripheral nerve regeneration, and could lead to the development of future nerve bio-conduits for clinical use. PMID:27572698

  1. Presacral abscess as a rare complication of sacral nerve stimulator implantation.

    PubMed

    Gumber, A; Ayyar, S; Varia, H; Pettit, S

    2017-03-01

    A 50-year-old man with intractable anal pain attributed to proctalgia fugax underwent insertion of a sacral nerve stimulator via the right S3 vertebral foramen for pain control with good symptomatic relief. Thirteen months later, he presented with signs of sepsis. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large presacral abscess. MRI demonstrated increased enhancement along the pathway of the stimulator electrode, indicating that the abscess was caused by infection introduced at the time of sacral nerve stimulator placement. The patient was treated with broad spectrum antibiotics, and the sacral nerve stimulator and electrode were removed. Attempts were made to drain the abscess transrectally using minimally invasive techniques but these were unsuccessful and CT guided transperineal drainage was then performed. Despite this, the presacral abscess progressed, developing enlarging gas locules and extending to the pelvic brim to involve the aortic bifurcation, causing hydronephrosis and radiological signs of impending sacral osteomyelitis. MRI showed communication between the rectum and abscess resulting from transrectal drainage. In view of the progressive presacral sepsis, a laparotomy was performed with drainage of the abscess, closure of the upper rectum and formation of a defunctioning end sigmoid colostomy. Following this, the presacral infection resolved. Presacral abscess formation secondary to an infected sacral nerve stimulator electrode has not been reported previously. Our experience suggests that in a similar situation, the optimal management is to perform laparotomy with drainage of the presacral abscess together with simultaneous removal of the sacral nerve stimulator and electrode.

  2. 3D-engineering of Cellularized Conduits for Peripheral Nerve Regeneration

    NASA Astrophysics Data System (ADS)

    Hu, Yu; Wu, Yao; Gou, Zhiyuan; Tao, Jie; Zhang, Jiumeng; Liu, Qianqi; Kang, Tianyi; Jiang, Shu; Huang, Siqing; He, Jiankang; Chen, Shaochen; Du, Yanan; Gou, Maling

    2016-08-01

    Tissue engineered conduits have great promise for bridging peripheral nerve defects by providing physical guiding and biological cues. A flexible method for integrating support cells into a conduit with desired architectures is wanted. Here, a 3D-printing technology is adopted to prepare a bio-conduit with designer structures for peripheral nerve regeneration. This bio-conduit is consisted of a cryopolymerized gelatin methacryloyl (cryoGelMA) gel cellularized with adipose-derived stem cells (ASCs). By modeling using 3D-printed “lock and key” moulds, the cryoGelMA gel is structured into conduits with different geometries, such as the designed multichannel or bifurcating and the personalized structures. The cryoGelMA conduit is degradable and could be completely degraded in 2-4 months in vivo. The cryoGelMA scaffold supports the attachment, proliferation and survival of the seeded ASCs, and up-regulates the expression of their neurotrophic factors mRNA in vitro. After implanted in a rat model, the bio-conduit is capable of supporting the re-innervation across a 10 mm sciatic nerve gap, with results close to that of the autografts in terms of functional and histological assessments. The study describes an indirect 3D-printing technology for fabricating cellularized designer conduits for peripheral nerve regeneration, and could lead to the development of future nerve bio-conduits for clinical use.

  3. Repair of peripheral nerve defects in rabbits using keratin hydrogel scaffolds.

    PubMed

    Hill, Paulina S; Apel, Peter J; Barnwell, Jonathan; Smith, Tom; Koman, L Andrew; Atala, Anthony; Van Dyke, Mark

    2011-06-01

    Entubulation of transected nerves using bioabsorbable conduits is a promising alternative to sural nerve autografting, but full functional recovery is rarely achieved. Numerous studies have suggested that scaffold-based conduit fillers may promote axon regeneration, but no neuroinductive biomaterial filler has been identified. We previously showed that a nerve guide filled with keratin hydrogel actively stimulates regeneration in a mouse model, and results in functional outcomes superior to empty conduits at early time points. The goal of the present study was to develop a peripheral nerve defect model in a rabbit and assess the effectiveness of a keratin hydrogel filler. Although repairs with keratin-filled conduits were not as consistently successful as autograft overall, the use of keratin resulted in a significant improvement in conduction delay compared to both empty conduits and autograft, as well as a significant improvement in amplitude recovery compared to empty conduits when measurable regeneration did occur. Taking into account all study animals (i.e., regenerated and nonregenerated), histological assessment showed that keratin-treated nerves had significantly greater myelin thickness than empty conduits. These data support the findings of our earlier study and suggest that keratin hydrogel fillers have the potential to be used clinically to improve conduit repair.

  4. Silk fibroin matrices for the controlled release of nerve growth factor (NGF).

    PubMed

    Uebersax, Lorenz; Mattotti, Marta; Papaloïzos, Michaël; Merkle, Hans P; Gander, Bruno; Meinel, Lorenz

    2007-10-01

    Nerve conduits (NC) for peripheral nerve repair should guide the sprouting axons and physically protect the axonal cone from any damage. The NC should also degrade after completion of its function to obviate the need of subsequent explanation and should optionally be suitable for controlled drug release of embedded growth factors to enhance nerve regeneration. Silk fibroin (SF) is a biocompatible and slowly biodegradable biomaterial with excellent mechanical properties that could meet the above stated requirements. SF material (films) supported the adherence and metabolic activity of PC12 cells, and, in combination with nerve growth factor (NGF), supported neurite outgrowth during PC12 cell differentiation. NGF-loaded SF-NC were prepared from aqueous solutions of NGF and SF (20%, w/w), which were air-dried or freeze-dried (freezing at -20 or -196 degrees C) in suitable molds. NGF release from the three differently prepared SF-NC was prolonged over at least 3 weeks, but the total amount released depended on the drying procedure of the NC. The potency of released NGF was retained within all formulations. Control experiments with differently dried NGF-lactose solutions did not evidence marked protein aggregation (SEC, HPLC), loss of ELISA-reactivity or PC12 cell bioactivity. This study encourages the further exploitation of SF-NC for growth factor delivery and evaluation in peripheral nerve repair.

  5. Polymer Functionalized Nanoparticles in Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Jayaraman, Arthi

    2013-03-01

    Significant interest has grown around the ability to control spatial arrangement of nanoparticles in a polymer nanocomposite to engineer materials with target properties. Past work has shown that one could achieve controlled assembly of nanoparticles in the polymer matrix by functionalizing nanoparticle surfaces with homopolymers. This talk will focus on our recent work using Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations and GPU-based molecular dynamics simulations to specifically understand how heterogeneity in the polymer functionalization in the form of a) copolymers with varying monomer chemistry and monomer sequence, and b) polydispersity in homopolymer grafts can tune effective interactions between functionalized nanoparticles, and the assembly of functionalized nanoparticles.

  6. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  7. Carbon dioxide laser-assisted nerve repair: effect of solder and suture material on nerve regeneration in rat sciatic nerve.

    PubMed

    Menovsky, Tomas; Beek, Johan F

    2003-01-01

    In order to further improve and explore the role of lasers for nerve reconstruction, this study was designed to investigate regeneration of sharply transected peripheral nerves repaired with a CO(2) milliwatt laser in combination with three different suture materials and a bovine albumin protein solder as an adjunct to the welding process. Unilateral sciatic nerve repair was performed in 44 rats. In the laser group, nerves were gently apposed, and two stay sutures (10-0 nylon, 10-0 polyglycolic acid, or 25 microm stainless steel) were placed epi/perineurially. Thereafter, the repair site was fused at 100 mW with pulses of 1.0 s. In the subgroup of laser-assisted nerve repair (LANR), albumen was used as a soldering agent to further reinforce the repair site. The control group consisted of nerves repaired by conventional microsurgical suture repair (CMSR), using 4-6 10-0 nylon sutures. Evaluation was performed at 1 and 6 weeks after surgery, and included qualitative and semiquantitative light microscopy. LANR performed with a protein solder results in a good early peripheral nerve regeneration, with an optimal alignment of nerve fibers and minimal connective tissue proliferation at the repair site. All three suture materials produced a foreign body reaction; the least severe was with polyglycolic acid sutures. CMSR resulted in more pronounced foreign-body granulomas at the repair site, with more connective-tissue proliferation and axonal misalignment. Furthermore, axonal regeneration in the distal nerve segment was better in the laser groups. Based on these results, CO(2) laser-assisted nerve repair with soldering in combination with absorbable sutures has the potential of allowing healing to occur with the least foreign-body reaction at the repair site. Further experiments using this combination are in progress.

  8. Two-level motor nerve transfer for the treatment of long thoracic nerve palsy.

    PubMed

    Ray, Wilson Z; Pet, Mitchell A; Nicoson, Michael C; Yee, Andrew; Kahn, Lorna C; Mackinnon, Susan E

    2011-10-01

    The authors report a case of long thoracic nerve (LTN) palsy treated with two-level motor nerve transfers of a pectoral fascicle of the middle trunk, and a branch of the thoracodorsal nerve. This procedure resulted in near-total improvement of the winged scapula deformity, and a return of excellent shoulder function. A detailed account of the postoperative physical therapy regimen is included, as this critical component of the favorable result cannot be overlooked. This case establishes the two-level motor nerve transfer as a new option for treating LTN palsy, and demonstrates that nerve transfers should be considered in the therapeutic algorithm of an idiopathic mononeuritis.

  9. Immediate versus delayed primary nerve repair in the rabbit sciatic nerve

    PubMed Central

    Piskin, Ahmet; Altunkaynak, Berrin Zühal; Çιtlak, Atilla; Sezgin, Hicabi; Yazιcι, Ozgür; Kaplan, Süleyman

    2013-01-01

    It is well known that peripheral nerve injury should be treated immediately in the clinic, but in some instances, repair can be delayed. This study investigated the effects of immediate versus delayed (3 days after injury) neurorrhaphy on repair of transected sciatic nerve in New Zealand rabbits using stereological, histomorphological and biomechanical methods. At 8 weeks after immediate and delayed neurorrhaphy, axon number and area in the sciatic nerve, myelin sheath and epineurium thickness, Schwann cell morphology, and the mechanical property of nerve fibers did not differ obviously. These results indicate that delayed neurorrhaphy do not produce any deleterious effect on sciatic nerve repair. PMID:25206663

  10. Modeling leukocyte trafficking at the human blood-nerve barrier in vitro and in vivo geared towards targeted molecular therapies for peripheral neuroinflammation.

    PubMed

    Greathouse, Kelsey M; Palladino, Steven P; Dong, Chaoling; Helton, Eric S; Ubogu, Eroboghene E

    2016-01-06

    Peripheral neuroinflammation is characterized by hematogenous mononuclear leukocyte infiltration into peripheral nerves. Despite significant clinical knowledge, advancements in molecular biology and progress in developing specific drugs for inflammatory disorders such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis, there are currently no specific therapies that modulate pathogenic peripheral nerve inflammation. Modeling leukocyte trafficking at the blood-nerve barrier using a reliable human in vitro model and potential intravital microscopy techniques in representative animal models guided by human observational data should facilitate the targeted modulation of the complex inflammatory cascade needed to develop safe and efficacious therapeutics for immune-mediated neuropathies and chronic neuropathic pain.

  11. Protective Action Guides (PAGs)

    EPA Pesticide Factsheets

    The Protective Action Guide (PAG) manual contains radiation dose guidelines that would trigger public safety measures. EPA developed Protective Action Guides to help responders plan for radiation emergencies.

  12. COATING ALTERNATIVES GUIDE (CAGE) USER'S GUIDE

    EPA Science Inventory

    The guide provides instructions for using the Coating Alternatives GuidE (CAGE) software program, version 1.0. It assumes that the user is familiar with the fundamentals of operating an IBM-compatible personal computer (PC) under the Microsoft disk operating system (MS-DOS). CAGE...

  13. Purely extradural spinal nerve root hemangioblastomas

    PubMed Central

    Aytar, Murat Hamit; Yener, Ulaş; Ekşi, Murat Şakir; Kaya, Behram; Özgen, Serdar; Sav, Aydin; Alanay, Ahmet

    2016-01-01

    Spinal nerve root hemangioblastomas present mostly as intradural-extradurally. Purely extradural spinal nerve root hemangioblastoma is a very rare entity. In this study, we aimed to analyze epidemiological perspectives of purely extradural spinal nerve root hemangioblastomas presented in English medical literature in addition to our own exemplary case. PubMed/MEDLINE was searched using the terms “hemangioblastoma,” “extradural,” “spinal,” and “nerve root.” Demographical variables of age, gender, concomitant presence of von Hippel–Lindau (VHL) disease; spinal imaging and/or intraoperative findings for tumor location were surveyed from retrieved articles. There are 38 patients with purely extradural spinal nerve root hemangioblastoma. The median age is 45 years (range = 24–72 years). Female:male ratio is 0.6. Spinal levels for purely extradural spinal nerve root hemangioblastomas, in order of decreasing frequency, are thoracic (48.6%), cervical (13.5%), lumbar (13.5%), lumbosacral (10.8%), sacral (8.1%), and thoracolumbar (5.4%). Concomitant presence of VHL disease is 45%. Purely extradural spinal nerve root hemangioblastomas are very rare and can be confused with other more common extradural spinal cord tumors. Concomitant presence of VHL disease is observed in less than half of the patients with purely extradural spinal nerve root hemangioblastomas. Surgery is the first-line treatment in these tumors. PMID:27891027

  14. Facial nerve paralysis after cervical traction.

    PubMed

    So, Edmund Cheung

    2010-10-01

    Cervical traction is a frequently used treatment in rehabilitation clinics for cervical spine problems. This modality works, in principle, by decompressing the spinal cord or its nerve roots by applying traction on the cervical spine through a harness placed over the mandible (Olivero et al., Neurosurg Focus 2002;12:ECP1). Previous reports on treatment complications include lumbar radicular discomfort, muscle injury, neck soreness, and posttraction pain (LaBan et al., Arch Phys Med Rehabil 1992;73:295-6; Lee et al., J Biomech Eng 1996;118:597-600). Here, we report the first case of unilateral facial nerve paralysis developed after 4 wks of intermittent cervical traction therapy. Nerve conduction velocity examination revealed a peripheral-type facial nerve paralysis. Symptoms of facial nerve paralysis subsided after prednisolone treatment and suspension of traction therapy. It is suspected that a misplaced or an overstrained harness may have been the cause of facial nerve paralysis in this patient. Possible causes were (1) direct compression by the harness on the right facial nerve near its exit through the stylomastoid foramen; (2) compression of the right external carotid artery by the harness, causing transient ischemic injury at the geniculate ganglion; or (3) coincidental herpes zoster virus infection or idiopathic Bell's palsy involving the facial nerve.

  15. Biomaterials and strategies for nerve regeneration.

    PubMed

    Huang, Yi-Cheng; Huang, Yi-You

    2006-07-01

    Nerve regeneration is a complex biological phenomenon. Once the nervous system is impaired, its recovery is difficult and malfunctions in other parts of the body may occur because mature neurons do not undergo cell division. To increase the prospects of axonal regeneration and functional recovery, researches have focused on designing "nerve guidance channels" or "nerve conduits." When developing ideal tissue-engineered nerve conduits, several components come to mind. They include a biodegradable and porous channel wall, the ability to deliver bioactive growth factors, incorporation of support cells, an internal oriented matrix to support cell migration, intraluminal channels to mimic the structure of nerve fascicles, and electrical activities. This article reviews the factors that are critical for nerve repair, and the advanced technologies that are explored to fabricate nerve conduits. To more accurately mimic natural repair in the body, recent studies have focused on the use of various advanced approaches to create ideal nerve conduits that combine multiple stimuli in an effort to better mimic the complex signals normally found in the body.

  16. A Safe Lab on Nerve Gases.

    ERIC Educational Resources Information Center

    Tucker, David C.

    1988-01-01

    Describes an experiment involving pineapples and gelatin that allows students to investigate the conditions that typically render an enzyme functionless, similar to the effect of nerve gasses. Discusses the materials, procedures, and results, drawing analogies to the effects of a nerve gas. (CW)

  17. Femoral nerve entrapment: a new insight.

    PubMed

    Vázquez, M T; Murillo, J; Maranillo, E; Parkin, I G; Sanudo, J

    2007-03-01

    Compression of the femoral nerve in the iliac fossa has been reported as a consequence of several pathologies, but never as a result of muscular compression. Aberrant slips of iliacus, however, have occasionally been reported to cover or split the femoral nerve. This study aimed to assess such variations as potential factors in femoral nerve compression. A large and homogeneous sample of 121 embalmed cadavers (242 specimens) was studied. Statistical comparisons were made using the chi-squared test. Muscular slips from iliacus and psoas, piercing or covering the femoral nerve, were found in 19 specimens (7.9%). No significant differences by sex or side were found. The more frequent variation was piercing of the femoral nerve by a muscular slip (17 specimens, 7.0%). The nerve then entered the thigh as one or more branches. The less frequent variation found was a muscular slip or sheet covering the femoral nerve as it lay on iliacus (2 specimens, 0.8%). Each disposition may be a potential risk for nerve entrapment.

  18. Use of natural neural scaffolds consisting of engineered vascular endothelial growth factor immobilized on ordered collagen fibers filled in a collagen tube for peripheral nerve regeneration in rats.

    PubMed

    Ma, Fukai; Xiao, Zhifeng; Meng, Danqing; Hou, Xianglin; Zhu, Jianhong; Dai, Jianwu; Xu, Ruxiang

    2014-10-15

    The search for effective strategies for peripheral nerve regeneration has attracted much attention in recent years. In this study, ordered collagen fibers were used as intraluminal fibers after nerve injury in rats. Vascular endothelial growth factor (VEGF) plays an important role in nerve regeneration, but its very fast initial burst of activity within a short time has largely limited its clinical use. For the stable binding of VEGF to ordered collagen fibers, we fused a collagen-binding domain (CBD) to VEGF through recombinant DNA technology. Then, we filled the ordered collagen fibers-CBD-VEGF targeting delivery system in a collagen tube to construct natural neural scaffolds, which were then used to bridge transected nerve stumps in a rat sciatic nerve transection model. After transplantation, the natural neural scaffolds showed minimal foreign body reactions and good integration into the host tissue. Oriented collagen fibers in the collagen tube could guide regenerating axons in an oriented manner to the distal, degenerating nerve segment, maximizing the chance of target reinnervation. Functional and histological analyses indicated that the recovery of nerve function in the natural neural scaffolds-treated group was superior to the other grafted groups. The guiding of oriented axonal regeneration and effective delivery systems surmounting the otherwise rapid and short-lived diffusion of growth factors in body fluids are two important strategies in promoting peripheral nerve regeneration. The natural neural scaffolds described take advantage of these two aspects and may produce synergistic effects. These properties qualified the artificial nerve conduits as a putative candidate system for the fabrication of peripheral nerve reconstruction devices.

  19. A silk sericin/silicone nerve guidance conduit promotes regeneration of a transected sciatic nerve.

    PubMed

    Xie, Hongjian; Yang, Wen; Chen, Jianghai; Zhang, Jinxiang; Lu, Xiaochen; Zhao, Xiaobo; Huang, Kun; Li, Huili; Chang, Panpan; Wang, Zheng; Wang, Lin

    2015-10-28

    Peripheral nerve gap defects lead to significant loss of sensory or motor function. Tissue engineering has become an important alternative to nerve repair. Sericin, a major component of silk, is a natural protein whose value in tissue engineering has just begun to be explored. Here, the first time use of sericin in vivo is reported as a long-term implant for peripheral nerve regeneration. A sericin nerve guidance conduit is designed and fabricated. This conduit is highly porous with mechanical strength matching peripheral nerve tissue. It supports Schwann cell proliferation and is capable of up-regulating the transcription of glial cell derived neurotrophic factor and nerve growth factor in Schwann cells. The sericin conduit wrapped with a silicone conduit (sericin/silicone double conduits) is used for bridging repair of a 5 mm gap in a rat sciatic nerve transection model. The sericin/silicone double conduits achieve functional recovery comparable to that of autologous nerve grafting as evidenced by drastically improved nerve function and morphology. Importantly, this improvement is mainly attributed to the sericin conduit as the silicone conduit alone only produces marginal functional recovery. This sericin/silicone-double-conduit strategy offers an efficient and valuable alternative to autologous nerve grafting for repairing damaged peripheral nerve.

  20. Cross-Face Nerve Grafting with Infraorbital Nerve Pathway Protection: Anatomic and Histomorphometric Feasibility Study

    PubMed Central

    Catapano, Joseph; Demsey, Daniel R.B.; Ho, Emily S.; Zuker, Ronald M.

    2016-01-01

    Smiling is an important aspect of emotional expression and social interaction, leaving facial palsy patients with impaired social functioning and decreased overall quality of life. Although there are several techniques available for facial reanimation, staged facial reanimation using donor nerve branches from the contralateral, functioning facial nerve connected to a cross-face nerve graft (CFNG) is the only technique that can reliably reproduce an emotionally spontaneous smile. Although CFNGs provide spontaneity, they typically produce less smile excursion than when the subsequent free functioning muscle flap is innervated with the motor nerve to the masseter muscle. This may be explained in part by the larger number of donor motor axons when using the masseter nerve, as studies have shown that only 20% to 50% of facial nerve donor axons successfully cross the nerve graft to innervate their targets. As demonstrated in our animal studies, increasing the number of donor axons that grow into and traverse the CFNG to innervate the free muscle transfer increases muscle movement, and this phenomenon may provide patients with the benefit of improved smile excursion. We have previously shown in animal studies that sensory nerves, when coapted to a nerve graft, improve axonal growth through the nerve graft and improve muscle excursion. Here, we describe the feasibility of and our experience in translating these results clinically by coapting the distal portion of the CFNG to branches of the infraorbital nerve. PMID:27757349

  1. Transient unilateral combined paresis of the hypoglossal nerve and lingual nerve following intubation anesthesia.

    PubMed

    Ulusoy, Hulya; Besir, Ahmet; Cekic, Bahanur; Kosucu, Muge; Geze, Sukran

    2014-01-01

    Nerve damage may occur in the pharyngolaryngeal region during general anesthesia. The most frequently injured nerves are the hypoglossal, lingual and recurrent laryngeal. These injuries may arise in association with several factors, such as laryngoscopy, endotracheal intubation and tube insertion, cuff pressure, mask ventilation, the triple airway maneuver, the oropharyngeal airway, manner of intubation tube insertion, head and neck position and aspiration. Nerve injuries in this region may take the form of an isolated single nerve or of paresis of two nerves together in the form of hypoglossal and recurrent laryngeal nerve palsy (Tapia's syndrome). However, combined injury of the lingual and hypoglossal nerves following intubation anesthesia is a much rarer condition. The risk of this damage can be reduced with precautionary measures. We describe a case of combined unilateral nervus hypoglossus and nervus lingualis paresis developing after intubation anesthesia.

  2. On the terminology of cranial nerves.

    PubMed

    Simon, František; Marečková-Štolcová, Elena; Páč, Libor

    2011-10-20

    The present contribution adopts various points of view to discuss the terminology of the twelve nervi craniales. These are paired nerves and have dual names, terms with Roman ordinal numerals, i.e., the nerves are numbered in the top-to-bottom direction, and descriptive historical names. The time of origin and motivation behind the investigated terms are determined. The majority of terms come from the 17th and 18th centuries. The motivation behind most of them is (a) nerve localization, as this is in conformity with anatomical nomenclature in general, (b) nerve function, and rarely (c) nerve appearance. The occurrence of synonymous names and variants is also a focus of attention. In several cases, reference is made to the process called terminologization, meaning when a certain expression acquires technical meaning and the characteristic/feature of the term.

  3. Ulnar nerve sonography in leprosy neuropathy.

    PubMed

    Wang, Zhu; Liu, Da-Yue; Lei, Yang-Yang; Yang, Zheng; Wang, Wei

    2016-01-01

    A 23-year-old woman presented with a half-year history of right forearm sensory and motor dysfunction. Ultrasound imaging revealed definite thickening of the right ulnar nerve trunk and inner epineurium, along with heterogeneous hypoechogenicity and unclear nerve fiber bundle. Color Doppler exhibited a rich blood supply, which was clearly different from the normal ulnar nerve presentation with a scarce blood supply. The patient subsequently underwent needle aspiration of the right ulnar nerve, and histopathological examination confirmed that granulomatous nodules had formed with a large number of infiltrating lymphocytes and a plurality of epithelioid cells in the fibrous connective tissues, with visible atypical foam cells and proliferous vascularization, consistent with leprosy. Our report will familiarize readers with the characteristic sonographic features of the ulnar nerve in leprosy, particularly because of the decreasing incidence of leprosy in recent years.

  4. Peripheral nerve morphogenesis induced by scaffold micropatterning

    PubMed Central

    Memon, Danish; Boneschi, Filippo Martinelli; Madaghiele, Marta; Brambilla, Paola; Del Carro, Ubaldo; Taveggia, Carla; Riva, Nilo; Trimarco, Amelia; Lopez, Ignazio D.; Comi, Giancarlo; Pluchino, Stefano; Martino, Gianvito; Sannino, Alessandro; Quattrini, Angelo

    2014-01-01

    Several bioengineering approaches have been proposed for peripheral nervous system repair, with limited results and still open questions about the underlying molecular mechanisms. We assessed the biological processes that occur after the implantation of collagen scaffold with a peculiar porous microstructure of the wall in a rat sciatic nerve transection model compared to commercial collagen conduits and nerve crush injury using functional, histological and genome wide analyses. We demonstrated that within 60 days, our conduit had been completely substituted by a normal nerve. Gene expression analysis documented a precise sequential regulation of known genes involved in angiogenesis, Schwann cells/axons interactions and myelination, together with a selective modulation of key biological pathways for nerve morphogenesis induced by porous matrices. These data suggest that the scaffold’s microstructure profoundly influences cell behaviors and creates an instructive micro-environment to enhance nerve morphogenesis that can be exploited to improve recovery and understand the molecular differences between repair and regeneration. PMID:24559639

  5. Meaningful power grip recovery after salvage reconstruction of a median nerve avulsion injury with a pedicled vascularized ulnar nerve

    PubMed Central

    Van Slyke, Aaron C; Jansen, Leigh A; Hynes, Sally; Hicks, Jane; Bristol, Sean; Carr, Nicholas

    2015-01-01

    In cases of median nerve injury alongside an unsalvageable ulnar nerve, a vascularized ulnar nerve graft to reconstruct the median nerve is a viable option. While restoration of median nerve sensation is consistently reported, recovery of significant motor function is less frequently observed. The authors report a case involving a previously healthy man who sustained upper arm segmental median and ulnar nerve injuries and, after failure of sural nerve grafts, was treated with a pedicled vascularized ulnar nerve graft to restore median nerve function. Long-term follow-up showed near full fist, with 12 kg of grip strength, key pinch with 1.5 kg of strength and protective sensation in the median nerve distribution. The present case demonstrates that pedicled ulnar vascularized nerve grafts can provide significant improvements to median nerve sensory and motor function in a heavily scarred environment. PMID:26665144

  6. Engineered neural tissue with aligned, differentiated adipose-derived stem cells promotes peripheral nerve regeneration across a critical sized defect in rat sciatic nerve.

    PubMed

    Georgiou, Melanie; Golding, Jon P; Loughlin, Alison J; Kingham, Paul J; Phillips, James B

    2015-01-01

    Adipose-derived stem cells were isolated from rats and differentiated to a Schwann cell-like phenotype in vitro. The differentiated cells (dADSCs) underwent self-alignment in a tethered type-1 collagen gel, followed by stabilisation to generate engineered neural tissue (EngNT-dADSC). The pro-regenerative phenotype of dADSCs was enhanced by this process, and the columns of aligned dADSCs in the aligned collagen matrix supported and guided neurite extension in vitro. EngNT-dADSC sheets were rolled to form peripheral nerve repair constructs that were implanted within NeuraWrap conduits to bridge a 15 mm gap in rat sciatic nerve. After 8 weeks regeneration was assessed using immunofluorescence imaging and transmission electron microscopy and compared to empty conduit and nerve graft controls. The proportion of axons detected in the distal stump was 3.5 fold greater in constructs containing EngNT-dADSC than empty tube controls. Our novel combination of technologies that can organise autologous therapeutic cells within an artificial tissue construct provides a promising new cellular biomaterial for peripheral nerve repair.

  7. Cadaveric nerve allotransplantation in the treatment of persistent thoracic neuralgia.

    PubMed

    Barbour, John R; Yee, Andrew; Moore, Amy M; Trulock, Elbert P; Buchowski, Jacob M; Mackinnon, Susan E

    2015-04-01

    When relief from neuralgia cannot be achieved with traditional methods, neurectomy may be considered to abate the stimulus, and primary opposition of the terminal nerve ending is recommended to prevent neuroma. Nerve repair with autograft is limited by autologous nerves available for large nerve defects. Cadaveric allografts provide an unlimited graft source without donor-site morbidities, but are rapidly rejected unless appropriate immunosuppression is achieved. An optimal treatment method for nerve allograft transplantation would minimize rejection while simultaneously permitting nerve regeneration. This report details a novel experience of nerve allograft transplantation using cadaveric nerve grafts to desensitize persistent postoperative thoracic neuralgia.

  8. Playing with Polymers.

    ERIC Educational Resources Information Center

    Chemecology, 1997

    1997-01-01

    Presents an activity that enables students to gain a better understanding of the importance of polymers. Students perform an experiment in which polymer chains of polyvinyl acetate form crosslinks. Includes background information and discussion questions. (DDR)

  9. Polymer composites containing nanotubes

    NASA Technical Reports Server (NTRS)

    Bley, Richard A. (Inventor)

    2008-01-01

    The present invention relates to polymer composite materials containing carbon nanotubes, particularly to those containing singled-walled nanotubes. The invention provides a polymer composite comprising one or more base polymers, one or more functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers and carbon nanotubes. The invention also relates to functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers, particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having side chain functionalization, and more particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having olefin side chains and alkyl epoxy side chains. The invention further relates to methods of making polymer composites comprising carbon nanotubes.

  10. Polymer Fluid Dynamics.

    ERIC Educational Resources Information Center

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  11. Introduction to Polymer Chemistry.

    ERIC Educational Resources Information Center

    Harris, Frank W.

    1981-01-01

    Reviews the physical and chemical properties of polymers and the two major methods of polymer synthesis: addition (chain, chain-growth, or chain-reaction), and condensation (step-growth or step-reaction) polymerization. (JN)

  12. Mechanical Properties of Polymers.

    ERIC Educational Resources Information Center

    Aklonis, J. J.

    1981-01-01

    Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

  13. Further Development of Scaffolds for Regeneration of Nerves

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey; Tuszynski, Mark

    2009-01-01

    Progress has been made in continuing research on scaffolds for the guided growth of nerves to replace damaged ones. The scaffolds contain pores that are approximately cylindrical and parallel, with nearly uniform widths ranging from tens to hundreds of microns. At the earlier stage of development, experimental scaffolds had been made from agarose hydrogel. Such a scaffold was made in a multistep process in which poly(methyl methacrylate) [PMMA] fibers were used as templates for the pores. The process included placement of a bundle of the PMMA fibers in a tube, filling the interstices in the tube with a hot agarose solution, cooling to turn the solution into a gel, and then immersion in acetone to dissolve the PMMA fibers. The scaffolds were typically limited to about 25 pores per scaffold, square cross sections of no more than about 1.5 by 1.5 mm, and lengths of no more than about 2 mm.

  14. ALUMINUM-CONTAINING POLYMERS

    DTIC Science & Technology

    ALUMINUM COMPOUNDS, *ORGANOMETALLIC COMPOUNDS, *POLYMERIZATION, *POLYMERS, ACRYLIC RESINS, ALKYL RADICALS, CARBOXYLIC ACIDS, COPOLYMERIZATION, LIGHT TRANSMISSION, STABILITY, STYRENES, TRANSPARENT PANELS.

  15. Dendritic polyurea polymers.

    PubMed

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  16. Engineered Protein Polymers

    DTIC Science & Technology

    2010-05-31

    of each pure polymer, we plan to combine the various polymer solutions in different ratios to tune the composition and physico-chemical properties...protein materials as vehicles for storage and delivery of small molecules. Each protein polymer under concentrations for particle formation ( vida

  17. Synthetic hydrophilic polymers

    NASA Astrophysics Data System (ADS)

    Rajasekharan Pillai, V. N.; Mutter, Manfred

    1981-11-01

    Synthetic hydrophilic polymers find promising applications in pharmacology, biotechnology and chemistry. The biocompatibility, biodegradability and pharmacological activity of these polymers depend much on their hydrophilic nature. This article summarizes the recent developments in the utilization of the different classes of these hydrophilic polymers as pharmacologically active agents, for enzyme modification and as catalysts and supports for chemical reactions.

  18. Dynamic covalent polymers.

    PubMed

    García, Fátima; Smulders, Maarten M J

    2016-11-15

    This Highlight presents an overview of the rapidly growing field of dynamic covalent polymers. This class of polymers combines intrinsic reversibility with the robustness of covalent bonds, thus enabling formation of mechanically stable, polymer-based materials that are responsive to external stimuli. It will be discussed how the inherent dynamic nature of the dynamic covalent bonds on the molecular level can be translated to the macroscopic level of the polymer, giving access to a range of applications, such as stimuli-responsive or self-healing materials. A primary distinction will be made based on the type of dynamic covalent bond employed, while a secondary distinction will be based on the consideration whether the dynamic covalent bond is used in the main chain of the polymer or whether it is used to allow side chain modification of the polymer. Emphasis will be on the chemistry of the dynamic covalent bonds present in the polymer, in particular in relation to how the specific (dynamic) features of the bond impart functionality to the polymer material, and to the conditions under which this dynamic behavior is manifested. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3551-3577.

  19. Biodegradable polymer optical fiber (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Chenji; Kalaba, Surge; Shan, Dingying; Xu, Kaitian; Yang, Jian; Liu, Zhiwen

    2016-10-01

    Biocompatible and even biodegradable polymers have unique advantages in various biomedical applications. Recent years, photonic devices fabricated using biocompatible polymers have been widely studied. In this work, we manufactured an optical fiber using biodegradable polymer POC and POMC. This step index optical fiber is flexible and easy to handle. Light was coupled into this polymer fiber by directly using objective. The fiber has a good light guiding property and an approximate loss of 2db/cm. Due to the two layer structure, our fiber is able to support applications inside biological tissue. Apart from remarkable optical performance, our fiber was also found capable of performing imaging. By measuring the impulse response of this multimode polymer fiber and using the linear inversion algorithm, concept proving experiments were completed. Images input into our fiber were able to be retrieved from the intensity distribution of the light at the output end. Experiment result proves the capability of our optical fiber to be used as a fiber endoscopy no needs to remove.

  20. Polymer photonic crystal fibre for sensor applications

    NASA Astrophysics Data System (ADS)

    Webb, David J.

    2010-04-01

    Polymer photonic crystal fibres combine two relatively recent developments in fibre technology. On the one hand, polymer optical fibre has very different physical and chemical properties to silica. In particular, polymer fibre has a much smaller Young's modulus than silica, can survive higher strains, is amenable to organic chemical processing and, depending on the constituent polymer, may absorb water. All of these features can be utilised to extend the range of applications of optical fibre sensors. On the other hand, the photonic crystal - or microstructured - geometry also offers advantages: flexibility in the fibre design including control of the dispersion properties of core and cladding modes, the possibility of introducing minute quantities of analyte directly into the electric field of the guided light and enhanced pressure sensitivity. When brought together these two technologies provide interesting possibilities for fibre sensors, particularly when combined with fibre Bragg or long period gratings. This paper discusses the features of polymer photonic crystal fibre relevant to sensing and provides examples of the applications demonstrated to date.