40 CFR Appendix I to Part 265 - Recordkeeping Instructions

Code of Federal Regulations, 2012 CFR

2012-07-01

... T10Infrared furnace incinerator T11Molten salt destructor T12Pyrolysis T13Wet Air oxidation T14Calcination... T21Chemical fixation T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination... Chloride Process Oxidation Reactor T89Methane Reforming Furnace T90Pulping Liquor Recovery Furnace...

Namib Desert primary productivity is driven by cryptic microbial community N-fixation.

PubMed

Ramond, Jean-Baptiste; Woodborne, Stephan; Hall, Grant; Seely, Mary; Cowan, Don A

2018-05-02

Carbon exchange in drylands is typically low, but during significant rainfall events (wet anomalies) drylands act as a C sink. During these anomalies the limitation on C uptake switches from water to nitrogen. In the Namib Desert of southern Africa, the N inventory in soil organic matter available for mineralisation is insufficient to support the observed increase in primary productivity. The C4 grasses that flourish after rainfall events are not capable of N fixation, and so there is no clear mechanism for adequate N fixation in dryland ecosystems to support rapid C uptake. Here we demonstrate that N fixation by photoautotrophic hypolithic communities forms the basis for the N budget for plant productivity events in the Namib Desert. Stable N isotope (δ 15 N) values of Namib Desert hypolithic biomass, and surface and subsurface soils were measured over 3 years across dune and gravel plain biotopes. Hypoliths showed significantly higher biomass and lower δ 15 N values than soil organic matter. The δ 15 N values of hypoliths approach the theoretical values for nitrogen fixation. Our results are strongly indicative that hypolithic communities are the foundation of productivity after rain events in the Namib Desert and are likely to play similar roles in other arid environments.

Irrigation management and phosphorus addition alter the abundance of carbon dioxide-fixing autotrophs in phosphorus-limited paddy soil.

PubMed

Wu, Xiaohong; Ge, Tida; Yan, Wende; Zhou, Juan; Wei, Xiaomeng; Chen, Liang; Chen, Xiangbi; Nannipieri, Paolo; Wu, Jinshui

2017-12-01

In this study, we assessed the interactive effects of phosphorus (P) application and irrigation methods on the abundances of marker genes (cbbL, cbbM, accA and aclB) of CO2-fixing autotrophs. We conducted rice-microcosm experiments using a P-limited paddy soil, with and without the addition of P fertiliser (P-treated-pot (P) versus control pot (CK)), and using two irrigation methods, namely alternate wetting and drying (AWD) and continuous flooding (CF). The abundances of bacterial 16S rRNA, archaeal 16S rRNA, cbbL, cbbM, accA and aclB genes in the rhizosphere soil (RS) and bulk soil (BS) were quantified. The application of P significantly altered the soil properties and stimulated the abundances of Bacteria, Archaea and CO2-fixation genes under CF treatment, but negatively influenced the abundances of Bacteria and marker genes of CO2-fixing autotrophs in BS soils under AWD treatment. The response of CO2-fixing autotrophs to P fertiliser depended on the irrigation management method. The redundancy analysis revealed that 54% of the variation in the functional marker gene abundances could be explained by the irrigation method, P fertiliser and the Olsen-P content; however, the rhizosphere effect did not have any significant influence. P fertiliser application under CF was more beneficial in improving the abundance of CO2-fixing autotrophs compared to the AWD treatment; thus, it is an ideal irrigation management method to increase soil carbon fixation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Metatranscriptomic and metagenomic description of the bacterial nitrogen metabolism in waste water wet oxidation effluents.

PubMed

Crovadore, Julien; Soljan, Vice; Calmin, Gautier; Chablais, Romain; Cochard, Bastien; Lefort, François

2017-10-01

Anaerobic digestion is a common method for reducing the amount of sludge solids in used waters and enabling biogas production. The wet oxidation process (WOX) improves anaerobic digestion by converting carbon into methane through oxidation of organic compounds. WOX produces effluents rich in ammonia, which must be removed to maintain the activity of methanogens. Ammonia removal from WOX could be biologically operated by aerobic granules. To this end, granulation experiments were conducted in 2 bioreactors containing an activated sludge (AS). For the first time, the dynamics of the microbial community structure and the expression levels of 7 enzymes of the nitrogen metabolism in such active microbial communities were followed in regard to time by metagenomics and metatranscriptomics. It was shown that bacterial communities adapt to the wet oxidation effluent by increasing the expression level of the nitrogen metabolism, suggesting that these biological activities could be a less costly alternative for the elimination of ammonia, resulting in a reduction of the use of chemicals and energy consumption in sewage plants. This study reached a strong sequencing depth (from 4.4 to 7.6 Gb) and enlightened a yet unknown diversity of the microorganisms involved in the nitrogen pathway. Moreover, this approach revealed the abundance and expression levels of specialised enzymes involved in nitrification, denitrification, ammonification, dissimilatory nitrate reduction to ammonium (DNRA) and nitrogen fixation processes in AS.

Comparison of effects of seven treatment methods for distal radius fracture on minimizing complex regional pain syndrome

PubMed Central

Sun, Tao

2016-01-01

Introduction Using network meta-analysis, we evaluated the adverse effects of the seven most common treatment methods, i.e., bridging external fixation, non-bridging external fixation, K-wire fixation, plaster fixation, dorsal plating, volar plating, and dorsal and volar plating, by their associated risk of developing complex regional pain syndrome (CRPS) in distal radius fracture (DRF) patients. Material and methods Following an exhaustive search of scientific literature databases for high quality studies, randomized controlled trials (RCTs) related to our study topic were screened and selected based on stringent predefined inclusion and exclusion criteria. Data extracted from the selected studies were used for statistical analyses using Stata 12.0 software. Results A total of 17 RCTs, including 1658 DRF patients, were enrolled in this network meta-analysis. Among the 1658 DRF patients, 452 received bridging external fixation, 525 received non-bridging external fixation, 154 received K-wire fixation, 84 received plaster fixation, 132 received dorsal plating, 123 received volar plating, and 188 received dorsal and volar plating. When compared to bridging external fixation patients, there was no marked difference in the CRPS risk in DRF patients receiving different treatments (all p > 0.05). However, the surface under the cumulative ranking curves (SUCRA) for plaster fixation (77.0%) and non-bridging external fixation (71.3%) were significantly higher compared with the other five methods. Conclusions Our findings suggest that compared with bridging external fixation, K-wire fixation, dorsal plating, volar plating, dorsal and volar plating, plaster fixation and non-bridging external fixation might be the better treatment methods to reduce the risk of CRPS in DRF patients. PMID:28144268

The Use of Mouse Models of Breast Cancer and Quantitative Image Analysis to Evaluate Hormone Receptor Antigenicity after Microwave-assisted Formalin Fixation

PubMed Central

Engelberg, Jesse A.; Giberson, Richard T.; Young, Lawrence J.T.; Hubbard, Neil E.

2014-01-01

Microwave methods of fixation can dramatically shorten fixation times while preserving tissue structure; however, it remains unclear if adequate tissue antigenicity is preserved. To assess and validate antigenicity, robust quantitative methods and animal disease models are needed. We used two mouse mammary models of human breast cancer to evaluate microwave-assisted and standard 24-hr formalin fixation. The mouse models expressed four antigens prognostic for breast cancer outcome: estrogen receptor, progesterone receptor, Ki67, and human epidermal growth factor receptor 2. Using pathologist evaluation and novel methods of quantitative image analysis, we measured and compared the quality of antigen preservation, percentage of positive cells, and line plots of cell intensity. Visual evaluations by pathologists established that the amounts and patterns of staining were similar in tissues fixed by the different methods. The results of the quantitative image analysis provided a fine-grained evaluation, demonstrating that tissue antigenicity is preserved in tissues fixed using microwave methods. Evaluation of the results demonstrated that a 1-hr, 150-W fixation is better than a 45-min, 150-W fixation followed by a 15-min, 650-W fixation. The results demonstrated that microwave-assisted formalin fixation can standardize fixation times to 1 hr and produce immunohistochemistry that is in every way commensurate with longer conventional fixation methods. PMID:24682322

A new adhesive technique for internal fixation in midfacial surgery

PubMed Central

Endres, Kira; Marx, Rudolf; Tinschert, Joachim; Wirtz, Dieter Christian; Stoll, Christian; Riediger, Dieter; Smeets, Ralf

2008-01-01

Background The current surgical therapy of midfacial fractures involves internal fixation in which bone fragments are fixed in their anatomical positions with osteosynthesis plates and corresponding screws until bone healing is complete. This often causes new fractures to fragile bones while drilling pilot holes or trying to insert screws. The adhesive fixation of osteosynthesis plates using PMMA bone cement could offer a viable alternative for fixing the plates without screws. In order to achieve the adhesive bonding of bone cement to cortical bone in the viscerocranium, an amphiphilic bone bonding agent was created, analogous to the dentin bonding agents currently on the market. Methods The adhesive bonding strengths were measured using tension tests. For this, metal plates with 2.0 mm diameter screw holes were cemented with PMMA bone cement to cortical bovine bone samples from the femur diaphysis. The bone was conditioned with an amphiphilic bone bonding agent prior to cementing. The samples were stored for 1 to 42 days at 37 degrees C, either moist or completely submerged in an isotonic NaCl-solution, and then subjected to the tension tests. Results Without the bone bonding agent, the bonding strength was close to zero (0.2 MPa). Primary stability with bone bonding agent is considered to be at ca. 8 MPa. Moist storage over 42 days resulted in decreased adhesion forces of ca. 6 MPa. Wet storage resulted in relatively constant bonding strengths of ca. 8 MPa. Conclusion A new amphiphilic bone bonding agent was developed, which builds an optimizied interlayer between the hydrophilic bone surface and the hydrophobic PMMA bone cement and thus leads to adhesive bonding between them. Our in vitro investigations demonstrated the adhesive bonding of PMMA bone cement to cortical bone, which was also stable against hydrolysis. The newly developed adhesive fixing technique could be applied clinically when the fixation of osteosynthesis plates with screws is impossible. With the detected adhesion forces of ca. 6 to 8 MPa, it is assumed that the adhesive fixation system is able to secure bone fragments from the non-load bearing midfacial regions in their orthotopic positions until fracture consolidation is complete. PMID:18489785

Porcine Intestinal Mast Cells. Evaluation of Different Fixatives for Histochemical Staining Techniques Considering Tissue Shrinkage

PubMed Central

Rieger, J.; Twardziok, S.; Huenigen, H.; Hirschberg, R.M.; Plendl, J.

2013-01-01

Staining of mast cells (MCs), including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF) has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkagedifferences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from data using different fixation techniques can only be compared if the respective studyimmanent shrinkage factor has been determined and quantification results are adjusted accordingly. PMID:24085270

[Comparison of external fixation with or without limited internal fixation for open knee fractures].

PubMed

Li, K N; Lan, H; He, Z Y; Wang, X J; Yuan, J; Zhao, P; Mu, J S

2018-03-01

Objective: To explore the characteristics and methods of different fixation methods and prevention of open knee joint fracture. Methods: The data of 86 cases of open knee joint fracture admitted from January 2002 to December 2015 in Department of Orthopaedics, Affiliated Hospital of Chengdu University were analyzed retrospectively.There were 65 males and 21 females aged of 38.6 years. There were 38 cases treated with trans articular external fixation alone, 48 cases were in the trans articular external fixation plus auxiliary limited internal fixation group. All the patients were treated according to the same three stages except for different fixation methods. Observation of external fixation and fracture fixation, fracture healing, wound healing and treatment, treatment and related factors of infection control and knee function recovery. χ(2) test was used to analyze data. Results: Eleven patients had primary wound healing, accounting for 12.8%. Seventy-five patients had two wounds healed, accounting for 87.2%. Only 38 cases of trans articular external fixator group had 31 cases of articular surface reduction, accounting for 81.6%; Five cases of trans articular external fixator assisted limited internal fixation group had 5 cases of poor reduction, accounting for 10.4%; There was significant difference between the two groups (χ(2)=44.132, P <0.05). Take a single cross joint external fixation group, a total of 23 cases of patients with infection, accounted for 60.5% of external fixation group; trans articular external fixation assisted limited internal fixation group there were 30 cases of patients with infection, accounting for the assistance of external fixator and limited internal fixation group 62.5%; There was significant difference between the two groups(χ(2)=0.035, P >0.05). Five cases of fracture nonunion cases of serious infection, patients voluntarily underwent amputation. The Lysholm Knee Scale: In the external fixation group, 23 cases were less than 50 points, accounting for 60.5%, 15 cases were more than 50 points, accounting for 39.5%, external fixation and limited internal fixation group 20 cases were less than 50 points, accounting for 41.7%, 28 cases were more than 50 points, accounting for 58.3%; There was significant difference between the two groups(χ(2)=1.279, P >0.05). Conclusions: Prevention and control of infection is a central link in the treatment of open fracture of the knee. Trans articular external fixator plus limited internal fixation is an important measure to treat open fracture of the knee-joint.

Salvage of infected total knee fusion: the last option.

PubMed

Wiedel, Jerome D

2002-11-01

Currently the most common indication for an arthrodesis of the knee is a failed infected total knee prosthesis. Other causes of a failed total knee replacement that might necessitate a knee fusion include aseptic loosening, deficient extensor mechanism, poor soft tissues, and Charcot joint. Techniques available for achieving a knee fusion are external fixation and internal fixation methods. The external fixation compression devices have been the most widely used for knee fusion and have been successful until the indications for fusion changed to mostly failed prosthetic knee replacement. With failed total knee replacement, the problem of severe bone loss became an issue, and the external fixation compression devices, even including the biplane external fixators, have been the least successful method reported for gaining fusion. The Ilizarov technique has been shown to achieve rigid fixation despite this bone loss, and a review of reports are showing high fusion rates using this method. Internal fixation methods including plate fixation and intramedullary nails have had the best success in gaining fusion in the face of this bone loss and have replaced external fixation methods as the technique of choice for knee fusion when severe bone loss is present. A review of the literature and a discussion of different fusion techniques are presented including a discussion of the influence that infection has on the success of fusion.

Fabrication of superhydrophobic fluorinated silica nanoparticles for multifunctional liquid marbles

NASA Astrophysics Data System (ADS)

Shang, Qianqian; Hu, Lihong; Hu, Yun; Liu, Chengguo; Zhou, Yonghong

2018-01-01

A facile one-pot method for the fabrication of superhydrophobic fluorinated silica nanoparticles is reported. Fluorinated aggregated silica (A-SiO2/FAS) nanoparticles were synthesized by controlling the nanoparticles assembly, in situ fixation and overgrowth of particle seeds with the assist of tetraethoxysilane (TEOS) in ethanol/water solution and then modification with fluoroalkylsilane (FAS) molecules. Such kind of A-SiO2/FAS nanoparticles showed superhydrophobicity and was not wetted by water, thus it could be served as the encapsulating shells to manipulate liquid droplets. Liquid marbles fabricated from A-SiO2/FAS nanoparticles were used for ammonia gas sensing or emitting by taking advantage of the porosity and superhydrophobicity of the liquid marble shells. In addition, the posibility of A-SiO2/FAS-based liquid marbles as microreactor for dopamine polymerization also was explored.

Relevance of ammonium oxidation within biological soil crust communities

USGS Publications Warehouse

Johnson, S.L.; Budinoff, C.R.; Belnap, J.; Garcia-Pichel, F.

2005-01-01

Thin, vertically structured topsoil communities that become ecologically important in arid regions (biological soil crusts or BSCs) are responsible for much of the nitrogen inputs into pristine arid lands. We studied N2 fixation and ammonium oxidation (AO) at subcentimetre resolution within BSCs from the Colorado Plateau. Pools of dissolved porewater nitrate/ nitrite, ammonium and organic nitrogen in wetted BSCs were high in comparison with those typical of aridosoils. They remained stable during incubations, indicating that input and output processes were of similar magnitude. Areal N2 fixation rates (6.5-48 ??mol C2H2 m-2 h -1) were high, the vertical distribution of N2 fixation peaking close to the surface if populations of heterocystous cyanobacteria were present, but in the subsurface if they were absent. Areal AO rates (19-46 ??mol N m-2 h-1) were commensurate with N2 fixation inputs. When considering oxygen availability, AO activity invariably peaked 2-3 mm deep and was limited by oxygen (not ammonium) supply. Most probable number (MPN)-enumerated ammonia-oxidizing bacteria (6.7-7.9 ?? 103 cells g-1 on average) clearly peaked at 2-3 mm depth. Thus, AO (hence nitrification) is a spatially restricted but important process in the nitrogen cycling of BSC, turning much of the biologically fixed nitrogen into oxidized forms, the fate of which remains to be determined.

Mesh fixation in endoscopic inguinal hernia repair: evaluation of methodology based on a systematic review of randomised clinical trials.

PubMed

Lederhuber, Hans; Stiede, Franziska; Axer, Stephan; Dahlstrand, Ursula

2017-11-01

The issue of mesh fixation in endoscopic inguinal hernia repair is frequently debated and still no conclusive data exist on differences between methods regarding long-term outcome and postoperative complications. The quantity of trials and the simultaneous lack of high-quality evidence raise the question how future trials should be planned. PubMed, EMBASE and the Cochrane Library were searched, using the filters "randomised clinical trials" and "humans". Trials that compared one method of mesh fixation with another fixation method or with non-fixation in endoscopic inguinal hernia repair were eligible. To be included, the trial was required to have assessed at least one of the following primary outcome parameters: recurrence; surgical site infection; chronic pain; or quality-of-life. Fourteen trials assessing 2161 patients and 2562 hernia repairs were included. Only two trials were rated as low risk for bias. Eight trials evaluated recurrence or surgical site infection; none of these could show significant differences between methods of fixation. Two of 11 trials assessing chronic pain described significant differences between methods of fixation. One of two trials evaluating quality-of-life showed significant differences between fixation methods in certain functions. High-quality evidence for differences between the assessed mesh fixation techniques is still lacking. From a socioeconomic and ethical point of view, it is necessary that future trials will be properly designed. As small- and medium-sized single-centre trials have proven unable to find answers, register studies or multi-centre studies with an evident focus on methodology and study design are needed in order to answer questions about mesh fixation in inguinal hernia repair.

Distal tibial pilon fractures (AO/OTA type B, and C) treated with the external skeletal and minimal internal fixation method.

PubMed

Milenković, Sasa; Mitković, Milorad; Micić, Ivan; Mladenović, Desimir; Najman, Stevo; Trajanović, Miroslav; Manić, Miodrag; Mitković, Milan

2013-09-01

Distal tibial pilon fractures include extra-articular fractures of the tibial metaphysis and the more severe intra-articular tibial pilon fractures. There is no universal method for treating distal tibial pilon fractures. These fractures are treated by means of open reduction, internal fixation (ORIF) and external skeletal fixation. The high rate of soft-tissue complications associated with primary ORIF of pilon fractures led to the use of external skeletal fixation, with limited internal fixation as an alternative technique for definitive management. The aim of this study was to estimate efficacy of distal tibial pilon fratures treatment using the external skeletal and minimal internal fixation method. We presented a series of 31 operated patients with tibial pilon fractures. The patients were operated on using the method of external skeletal fixation with a minimal internal fixation. According to the AO/OTA classification, 17 patients had type B fracture and 14 patients type C fractures. The rigid external skeletal fixation was transformed into a dynamic external skeletal fixation 6 weeks post-surgery. This retrospective study involved 31 patients with tibial pilon fractures, average age 41.81 (from 21 to 60) years. The average follow-up was 21.86 (from 12 to 48) months. The percentage of union was 90.32%, nonunion 3.22% and malunion 6.45%. The mean to fracture union was 14 (range 12-20) weeks. There were 4 (12.19%) infections around the pins of the external skeletal fixator and one (3.22%) deep infections. The ankle joint arthrosis as a late complication appeared in 4 (12.90%) patients. All arthroses appeared in patients who had type C fractures. The final functional results based on the AOFAS score were excellent in 51.61%, good in 32.25%, average in 12.90% and bad in 3.22% of the patients. External skeletal fixation and minimal internal fixation of distal tibial pilon fractures is a good method for treating all types of inta-articular pilon fractures. In fractures types B and C dynamic external skeletal fixation allows early mobility in the ankle joint.

Biomechanical evaluation of three different fixation methods of the Chevron osteotomy of the olecranon: an analysis with Roentgen Stereophotogrammatic Analysis.

PubMed

Wagener, Marc L; Driesprong, Marco; Heesterbeek, Petra J C; Verdonschot, Nico; Eygendaal, Denise

2013-08-01

In this study three different methods for fixating the Chevron osteotomy of the olecranon are evaluated. Transcortical fixed Kirschner wires with a tension band, a large cancellous screw with a tension band, and a large cancellous screw alone are compared using Roentgen Stereophotogrammatic Analysis (RSA). The different fixation methods were tested in 17 cadaver specimens by applying increasing repetitive force to the triceps tendon. Forces applied were 200N, 350N, and 500N. Translation and rotation of the osteotomy were recorded using Roentgen Stereophotogrammatic Analysis. Both the fixations with a cancellous screw with tension band and with bi-cortical placed Kirschner wires with a tension band provide enough stability to withstand the forces of normal daily use. Since fixation with a cancellous screw with tension band is a fast and easy method and is related to minimal soft tissue damage this method can preferably be used for fixation of a Chevron osteotomy of the olecranon. © 2013.

Comparison of Tibiofemoral Contact Mechanics After Various Transtibial and All-Inside Fixation Techniques for Medial Meniscus Posterior Root Radial Tears in a Porcine Model.

PubMed

Chung, Kyu Sung; Choi, Choong Hyeok; Bae, Tae Soo; Ha, Jeong Ku; Jun, Dal Jae; Wang, Joon Ho; Kim, Jin Goo

2018-04-01

To compare tibiofemoral contact mechanics after fixation for medial meniscus posterior root radial tears (MMPRTs). Seven fresh knees from mature pigs were used. Each knee was tested under 5 conditions: normal knee, MMPRT, pullout fixation with simple sutures, fixation with modified Mason-Allen sutures, and all-inside fixation using Fastfix 360. The peak contact pressure and contact surface area were evaluated using a capacitive sensor positioned between the meniscus and tibial plateau, under a 1,000-N compression force, at different flexion angles (0°, 30°, 60°, and 90°). The peak contact pressure was significantly higher in MMPRTs than in normal knees (P = .018). Although the peak contact pressure decreased significantly after fixation at all flexion angles (P = .031), it never recovered to the values noted in the normal meniscus. No difference was observed among fixation groups (P = .054). The contact surface area was significantly lower in MMPRTs than in the normal meniscus (P = .018) and increased significantly after fixation at all flexion angles (P = .018) but did not recover to within normal limits. For all flexion angles except 60°, the contact surface area was significantly higher for fixation with Mason-Allen sutures than for fixation with simple sutures or all-inside fixation (P = .027). At 90° of flexion, the contact surface area was significantly better for fixation with simple sutures than for all-inside fixation (P = .031). The peak contact pressure and contact surface area improved significantly after fixation, regardless of the fixation method, but did not recover to the levels noted in the normal meniscus after any type of fixation. Among the fixation methods evaluated in this time 0 study, fixation using modified Mason-Allen sutures provided a superior contact surface area compared with that noted after fixation using simple sutures or all-inside fixation, except at 60° of flexion. However, this study had insufficient power to accurately detect the differences between the outcomes of various fixation methods. Our results in a porcine model suggest that fixation can restore tibiofemoral contact mechanics in MMPRT and that fixation with a locking mechanism leads to superior biomechanical properties. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Comparison of screw fixation with elastic fixation methods in the treatment of syndesmosis injuries in ankle fractures.

PubMed

Seyhan, Mustafa; Donmez, Ferdi; Mahirogullari, Mahir; Cakmak, Selami; Mutlu, Serhat; Guler, Olcay

2015-07-01

17 patients with ankle syndesmosic injury were treated with a 4.5mm single cortical screw fixation (passage of screw 4 cortices) and 15 patients were treated with single-level elastic fixation material. All patients were evaluated according to the AOFAS ankle and posterior foot scale at the third, sixth and twelfth months after the fixation. The ankle range of movement was recorded together with the healthy side. The Student's t test was used for statistical comparisons. No statistical significant difference was observed between the AOFAS scores (p>0.05). The range of dorsiflexion and plantar flexion motion of the elastic fixation group at the 6th and 12th months were significantly better compared to the screw fixation group (p<0.01). Elastic fixation is as functional as screw fixation in the treatment of ankle syndesmosis injuries. The unnecessary need of a second surgical intervention for removal of the fixation material is another advantageous aspect of this method of fixation. Copyright © 2015. Published by Elsevier Ltd.

Fixation strength analysis of cup to bone material using finite element simulation

NASA Astrophysics Data System (ADS)

Anwar, Iwan Budiwan; Saputra, Eko; Ismail, Rifky; Jamari, J.; van der Heide, Emile

2016-04-01

Fixation of acetabular cup to bone material is an important initial stability for artificial hip joint. In general, the fixation in cement less-type acetabular cup uses press-fit and screw methods. These methods can be applied alone or together. Based on literature survey, the additional screw inside of cup is effective; however, it has little effect in whole fixation. Therefore, an acetabular cup with good fixation, easy manufacture and easy installation is required. This paper is aiming at evaluating and proposing a new cup fixation design. To prove the strength of the present cup fixation design, the finite element simulation of three dimensional cup with new fixation design was performed. The present cup design was examined with twist axial and radial rotation. Results showed that the proposed cup design was better than the general version.

Fractures of the capitellum--a comparison of two fixation methods.

PubMed

Poynton, A R; Kelly, I P; O'Rourke, S K

1998-06-01

Isolated capitellar fractures are rare, accounting for only 1 per cent of all elbow fractures (Bryan and Morrey, The Elbow and its Disorders, 1985). Many different fixation methods have been described but no series has compared these treatment modalities because of the rarity of these fractures. This paper compares the outcome of two types of fixation of type I capitellar fractures. Group one (n = 6) had open reduction and Kirschner wire fixation while group two (n = 6) had open reduction and Herbert screw fixation. Both groups were compared clinically, functionally and radiographically. We found that Herbert screw fixation enabled earlier mobilization and a better functional outcome.

Sporicidal activity of chemical and physical tissue fixation methods.

PubMed Central

Vardaxis, N J; Hoogeveen, M M; Boon, M E; Hair, C G

1997-01-01

AIMS: The effects of alcohol based fixation and microwave stimulated alcohol fixation were investigated on spores of Bacillus stearothermophilus and Bacillus subtilis (var. niger). METHODS: Spores were exposed to 10% formalin, or different concentrations of various alcohol containing fixatives (Kryofix/Spuitfix). Adequate controls were also set up in conjunction with the test solutions. The spores were immersed with and without adjunctive microwave stimulation in the various solutions tested. Possible surviving spores were recovered in revival broth and after incubation, and Gram staining viable counts were performed. RESULTS: Alcohol based fixatives did not have a sporicidal effect on B stearothermophilus or B subtilis (var. niger) spores, and microwave stimulated alcohol fixation at 450 W and up to 75 degrees C did not have a sporicidal effect. CONCLUSIONS: When alcohol based fixatives are used for fixation, precautions should be taken with the material thus treated, as it may contain viable spores or other pathogens, which are destroyed after 24 hours of formalin treatment. Of the physicochemical methods tested involving microwaving, none was successful in eliminating viable spores from the test material. PMID:9215128

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness

PubMed Central

M. Mallery, Robert; Poolman, Pieter; J. Thurtell, Matthew; Wang, Jui-Kai; K. Garvin, Mona; Ledolter, Johannes; Kardon, Randy H.

2016-01-01

Purpose The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Methods Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Results Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Conclusions Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure–function relationship between fixation and areas of preserved GCC in patients with ON. PMID:27409502

Tolerance or avoidance: drought frequency determines the response of an N2 -fixing tree.

PubMed

Minucci, Jeffrey M; Miniat, Chelcy Ford; Teskey, Robert O; Wurzburger, Nina

2017-07-01

Climate change is increasing drought frequency, which may affect symbiotic N 2 fixation (SNF), a process that facilitates ecosystem recovery from disturbance. Here, we assessed the effect of drought frequency on the ecophysiology and SNF rate of a common N 2 -fixing tree in eastern US forests. We grew Robinia pseudoacacia seedlings under the same mean soil moisture, but with different drought frequency caused by wet-dry cycles of varying periodicity. We found no effect of drought frequency on final biomass or mean SNF rate. However, seedlings responded differently to wet and dry phases depending on drought frequency. Under low-frequency droughts, plants fixed carbon (C) and nitrogen (N) at similar rates during wet and dry phases. Conversely, under high-frequency droughts, plants fixed C and N at low rates during dry phases and at high rates during wet phases. Our findings suggest that R. pseudoacacia growth is resistant to increased drought frequency because it employs two strategies - drought tolerance or drought avoidance, followed by compensation. SNF may play a role in both by supplying N to leaf tissues for acclimation and by facilitating compensatory growth following drought. Our findings point to SNF as a mechanism for plants and ecosystems to cope with drought. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

[Development and current situation of reconstruction methods following total sacrectomy].

PubMed

Huang, Siyi; Ji, Tao; Guo, Wei

2018-05-01

To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy. The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized. After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system. Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.

Tension degradation of anterior cruciate ligament grafts with dynamic flexion-extension loading: a biomechanical model in porcine knees.

PubMed

Dargel, Jens; Koebke, Jürgen; Brüggemann, Gert-Peter; Pennig, Dietmar; Schmidt-Wiethoff, Rüdiger

2009-10-01

This study investigates the influence of various femoral anterior cruciate ligament graft fixation methods on the amount of tension degradation and the initial fixation strength after cyclic flexion-extension loading in a porcine knee model. One hundred twenty porcine digital extensor tendons, used as 4-stranded free tendon grafts, were fixated within porcine femoral bone tunnels by use of extracortical button, cross-pin, or interference screw fixation. One hundred twenty porcine patellar tendon-bone grafts were fixated by use of cross-pin, interference screw, or press-fit fixation. Each femur-graft complex was submitted to cyclic flexion-extension loading for 1,000 cycles throughout different loading ranges, and the total loss of tension was determined. After cyclic testing, the grafts were loaded to failure, and the data were compared with a pullout series without cyclic loading. Tension degradation after 1,000 cycles of flexion-extension loading averaged 62.6% +/- 10.0% in free tendon grafts and 48.9% +/- 13.35% in patellar tendon-bone grafts. There was no influence of the loading range on the total amount of tension degradation. The total amount of tension degradation was the highest with interference screw fixation of free tendon and patellar tendon-bone grafts. Despite excessive loss of tension, the initial fixation strength of the femur-graft complex was not reduced. The method of femoral graft fixation significantly influenced tension degradation during dynamic flexion-extension loading. Femoral graft fixation methods that secure the graft close to the tunnel entrance and that displace the graft substance from the center of the bone tunnel show the largest amount of tension degradation during cyclic flexion-extension loading. The graft substance, not the fixation site, was the weakest link of the graft complex within this investigation. We believe that the graft fixation method should be considered when aiming to improve the precision of femoral graft placement in anterior cruciate ligament reconstruction.

Discriminating between intentional and unintentional gaze fixation using multimodal-based fuzzy logic algorithm for gaze tracking system with NIR camera sensor

NASA Astrophysics Data System (ADS)

Naqvi, Rizwan Ali; Park, Kang Ryoung

2016-06-01

Gaze tracking systems are widely used in human-computer interfaces, interfaces for the disabled, game interfaces, and for controlling home appliances. Most studies on gaze detection have focused on enhancing its accuracy, whereas few have considered the discrimination of intentional gaze fixation (looking at a target to activate or select it) from unintentional fixation while using gaze detection systems. Previous research methods based on the use of a keyboard or mouse button, eye blinking, and the dwell time of gaze position have various limitations. Therefore, we propose a method for discriminating between intentional and unintentional gaze fixation using a multimodal fuzzy logic algorithm applied to a gaze tracking system with a near-infrared camera sensor. Experimental results show that the proposed method outperforms the conventional method for determining gaze fixation.

Strength of surgical wire fixation. A laboratory study.

PubMed

Guadagni, J R; Drummond, D S

1986-08-01

Because of the frequent use of stainless steel wire in spinal surgery and to augment fracture fixation, several methods of securing wire fixation were tested in the laboratory to determine the relative strength of fixation. Any method of fixation stronger than the yield strength of the wire is sufficient. Square knots, knot twists, symmetric twists, and the AO loop-tuck techniques afforded acceptable resistance against tension loads, but the wire wrap and AO loop technique were unacceptable. The double symmetric twist, which is frequently used for tension banding, was barely acceptable. The symmetric twist technique was the most practical because it is strong enough, efficient in maintaining tension applied during fixation, and least likely to cause damage to the wire. To optimize the fixation strength of the symmetrical twist, at least two twists are required at a reasonably tight pitch.

Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis.

PubMed

Latt, L Daniel; Glisson, Richard R; Adams, Samuel B; Schuh, Reinhard; Narron, John A; Easley, Mark E

2015-10-01

Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation. Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint. The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method. The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that which can be obtained with 3 headless compression screws. Screw and external fixator performance did not correlate with bone mineral density. This study supports the use of external fixation as an alternative method of generating compression to help stimulate fusion across the transverse tarsal joints. The findings provide biomechanical evidence to support the use of external fixation as a viable option in transverse tarsal joint fusion cases in which screw fixation has failed or is anticipated to be inadequate due to suboptimal bone quality. © The Author(s) 2015.

Comparison of Risk of Carpal Tunnel Syndrome in Patients with Distal Radius Fractures After 7 Treatments

PubMed Central

Zhao, Huan-Li; Wang, Gui-Bin; Jia, Yue-Qing; Zhu, Shi-Cai; Zhang, Feng-Fang; Liu, Hong-Mei

2015-01-01

Background To compare risk of carpal tunnel syndrome (CTS) in distal radius fracture (DRF) patients after 7 treatments using bridging external fixation (BrEF), non-bridging external fixation (non-BrEF), plaster fixation, K-wire fixation, dorsal plating fixation, volar plating fixation, and dorsal and volar plating by performing a network meta-analysis. Material/Methods An exhaustive search of electronic databases identified randomized controlled trails (RCTs) closely related to our study topic. The published articles were screened, based on predefined inclusion and exclusion criteria, to select high-quality studies for the present network meta-analysis. Data extracted from the selected studies were analyzed using STATA version 12.0 software. Results The literature search and selection process identified 12 eligible RCTs that contained a total of 1370 DRF patients (394 patients with BrEF, 377 patients with non-BrEF, 89 patients with K-wire fixation, 192 patients with plaster fixation, 42 patients with dorsal plating fixation, 152 patients with volar plating fixation, and 124 patients with dorsal and volar plating fixation). Our network meta-analysis results demonstrated no significant differences in CTS risk among the 7 treatments (P>0.05). The value of surface under the cumulative ranking curve (SUCRA), however, suggested that dorsal plating fixation is the optimal treatment, with the lowest risk of CTS in DRF patients (dorsal plating fixation: 89.2%; dorsal and volar plating: 57.8%; plaster fixation: 50.9%; non-BrEF: 50.6%; volar plating fixation: 39.6%; BrEF: 38.4%; K-wire fixation: 23.6%). Conclusions Our network meta-analysis provides evidence that dorsal plating fixation significantly decreases the risk of CTS and could be the method of choice in DRF patients. PMID:26391617

Screw-Wire Osteo-Traction: An Adjunctive or Alternative Method of Anatomical Reduction of Multisegment Midfacial Fractures? A Description of Technique and Prospective Study of 40 Patients

PubMed Central

O'Regan, Barry; Devine, Maria; Bhopal, Sats

2013-01-01

Stable anatomical fracture reduction and segment control before miniplate fixation can be difficult to achieve in comminuted midfacial fractures. Fracture mobilization and reduction methods include Gillies elevation, malar hook, and Dingman elevators. No single method is used universally. Disadvantages include imprecise segment alignment and poor segment stability/control. We have employed screw-wire osteo-traction (SWOT) to address this problem. A literature review revealed two published reports. The aims were to evaluate the SWOT technique effectiveness as a fracture reduction method and to examine rates of revision fixation and plate removal. We recruited 40 consecutive patients requiring open reduction and internal fixation of multisegment midfacial fractures (2009–2012) and employed miniplate osteosynthesis in all patients. SWOT was used as a default reduction method in all patients. The rates of successful fracture reduction achieved by SWOT alone or in combination and of revision fixation and plate removal, were used as outcome indices of the reduction method effectiveness. The SWOT technique achieved satisfactory anatomical reduction in 27/40 patients when used alone. Other reduction methods were also used in 13/40 patients. No patient required revision fixation and three patients required late plate removal. SWOT can be used across the midface fracture pattern in conjunction with other methods or as a sole reduction method before miniplate fixation. PMID:24436763

Acrylic Resin Molding Based Head Fixation Technique in Rodents.

PubMed

Roh, Mootaek; Lee, Kyungmin; Jang, Il-Sung; Suk, Kyoungho; Lee, Maan-Gee

2016-01-12

Head fixation is a technique of immobilizing animal's head by attaching a head-post on the skull for rigid clamping. Traditional head fixation requires surgical attachment of metallic frames on the skull. The attached frames are then clamped to a stationary platform resulting in immobilization of the head. However, metallic frames for head fixation have been technically difficult to design and implement in general laboratory environment. In this study, we provide a novel head fixation method. Using a custom-made head fixation bar, head mounter is constructed during implantation surgery. After the application of acrylic resin for affixing implants such as electrodes and cannula on the skull, additional resins applied on top of that to build a mold matching to the port of the fixation bar. The molded head mounter serves as a guide rails, investigators conveniently fixate the animal's head by inserting the head mounter into the port of the fixation bar. This method could be easily applicable if implantation surgery using dental acrylics is necessary and might be useful for laboratories that cannot easily fabricate CNC machined metal head-posts.

Microwave energy fixation for electron microscopy.

PubMed Central

Login, G. R.; Dvorak, A. M.

1985-01-01

We have demonstrated that microwave energy (MW) can be used in conjunction with chemical cross-linking agents in order to rapidly fix cell suspensions and tissue blocks for electron microscopy in 7-9 seconds. The optimal MW fixation method involved immersing tissues up to 1 cu cm in dilute aldehyde fixation and immediately irradiating the specimens in a conventional microwave oven for 9 seconds to 50 C. Ultrastructural preservation of samples irradiated by MW energy was comparable to that of the control samples immersed in aldehyde fixative for 2 hours at 25 C. Stereologic analysis showed that tissue blocks fixed by the MW fixation method did not cause organelles such as liver mitochondria and salivary gland granules to shrink or to swell. Potential applications for this new fixation technology include the investigation of rapid intracellular processes (eg, vesicular transport) and preservation of proteins that are difficult to demonstrate with routine fixation methods (eg, antigens and enzymes). Images Figure 4 Figure 5 Figure 2 Figure 3 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 PMID:3927740

Surgical Intervention for Instability of the Craniovertebral Junction

PubMed Central

TAKAYASU, Masakazu; AOYAMA, Masahiro; JOKO, Masahiro; TAKEUCHI, Mikinobu

2016-01-01

Surgical approaches for stabilizing the craniovertebral junction (CVJ) are classified as either anterior or posterior approaches. Among the anterior approaches, the established method is anterior odontoid screw fixation. Posterior approaches are classified as either atlanto-axial fixation or occipito-cervical (O-C) fixation. Spinal instrumentation using anchor screws and rods has become a popular method for posterior cervical fixation. Because this method achieves greater stability and higher success rates for fusion without the risk of sublaminar wiring, it has become a substitute for previous methods that used bone grafting and wiring. Several types of anchor screws are available, including C1/2 transarticular, C1 lateral mass, C2 pedicle, and translaminar screws. Appropriate anchor screws should be selected according to characteristics such as technical feasibility, safety, and strength. With these stronger anchor screws, shorter fixation has become possible. The present review discusses the current status of surgical interventions for stabilizing the CVJ. PMID:27041630

An ex vivo mechanical evaluation of single versus double semitubular plate fixation of a transverse distal-third scapular osteotomy in the dog.

PubMed

Mair, Jacqueline J; Belkoff, Stephen M; Boudrieau, Randy J

2003-01-01

To compare single versus double semitubular plate fixation for scapular body fractures. Ex vivo mechanical study. Eighteen paired cadaveric canine scapulae. Transverse scapular body osteotomies were created in the distal third of 18 pairs of scapulae. One scapula of each pair was repaired with a single plate, whereas the contralateral scapula was repaired with 2 plates. Initial strength and stiffness of the constructs were measured in 10 pairs of scapulae. Eight pairs of scapulae underwent cyclic loading and then were subjected to failure testing. Double-plate fixation was significantly stronger (3,899 +/- 632 N) but not stiffer (614 +/- 130 N/mm) than the single-plate fixation (3,238 +/- 935 N and 537 +/- 202 N/mm, respectively). Cyclic loading variables were not significantly different between the 2 methods of fixation. After cyclic loading, double-plate fixation was significantly stronger (2,916 +/- 618 N) than single-plate fixation (2,347 +/- 495 N). There was no significant difference (P =.11) in stiffness between double- versus single-plate fixations: 734 +/- 247 N/mm and 595 +/- 139 N/mm, respectively. Double-plate fixation was generally stronger and stiffer than single-plate fixation. Because all constructs failed at loads that greatly exceeded those estimated to occur clinically, any difference between the 2 methods of fixation probably is not clinically relevant. Single-plate fixation may be of sufficient strength for fixation of scapular body fractures. Copyright 2003 by The American College of Veterinary Surgeons

Influence of dielectric barrier discharge treatment on mechanical and dyeing properties of wool

NASA Astrophysics Data System (ADS)

Rahul, NAVIK; Sameera, SHAFI; Md Miskatul, ALAM; Md Amjad, FAROOQ; Lina, LIN; Yingjie, CAI

2018-06-01

Physical and chemical properties of wool surface significantly affect the absorbency, rate of dye bath exhaustion and fixation of the industrial dyes. Hence, surface modification is a necessary operation prior to coloration process in wool wet processing industries. Plasma treatment is an effective alternative for physiochemical modification of wool surface. However, optimum processing parameters to get the expected modification are still under investigation, hence this technology is still under development in the wool wet processing industries. Therefore, in this paper, treatment parameters with the help of simple dielectric barrier discharge plasma reactor and air as a plasma gas, which could be a promising combination for treatment of wool substrate at industrial scale were schematically studied, and their influence on the water absorbency, mechanical, and dyeing properties of twill woven wool fabric samples are reported. It is expected that the results will assist to the wool coloration industries to improve the dyeing processes.

The effect of fixatives and temperature on the quality of glycogen demonstration.

PubMed

Zakout, Yosef Mohamed Azzam; Salih, Magdi M; Ahmed, H G

2010-04-01

Glycogen is demonstrated in a number of lesions and is diagnostically significant, particularly in certain tumors. To stain glycogen accurately, it is essential to choose a suitable fixative, temperature and staining method. We used rabbit liver to assess these variables. Specimens were fixed in three fixatives at two temperatures: 10% formalin, neutral buffered formalin (NBF) and Bouin's solution at 37 and 4 degrees C. Seventy-two paraffin sections were prepared and stained with periodic acid-Schiff (PAS), hexamine (methenamine) silver and Best's carmine methods. Negative control sections using diastase digestion were used for all methods to confirm the presence of glycogen. For the PAS reaction, Bouin's fixative gave better results at both temperatures compared to the other fixatives. For hexamine (methenamine) silver, the quality of staining was improved for tissues fixed in both 10% formalin and NBF at 37 degrees C compared to Bouin's solution. Both 10% formalin and NBF at 4 degrees C gave better results than Bouin's solution. For Best's carmine, Bouin's solution gave the best results for tissues fixed at 4 degrees C. Fixation of tissues with NBF at 37 degrees C gave the best quality staining. We concluded that the quality of glycogen staining in paraffin sections is greatly affected by both the fixative and the temperature of fixation.

Limb lengthening over a nail can safely reduce the duration of external fixation

PubMed Central

Chaudhary, Milind

2008-01-01

Background: Limb lengthening using Ilizarov external fixation is safe, but the consolidation phase tends to take too long. A method that can safely reduce the time spent in external fixation would help increase patient tolerance and comfort. We report our results of lengthening over nails (LON) method in which an interlocking nail was used along with an Ilizarov external fixator to reduce external fixation duration in limb lengthening. This is a retrospective study. Materials and Methods: Twenty-seven lengthening surgeries were done with the LON method in 23 patients with 22 tibiae and five femora during the last 12 years. Length gain ranged from 1.5 cm to a maximum of 9.8 cm with a mean of 4.6 cm. The mean modified Paley difficulty score was 7.6 points. Fourteen associated procedures were performed in these patients, including equinus contracture releases, supracondylar osteotomies, ilizarov hip reonstruction and ankle fusion. We had a 29% rate of complications which included one problem, three obstacles and four complications with no serious deep intramedullary infections. Our rate of complications compares favorably with series reported in the literature. External fixation duration was reduced significantly to a mean of 17.8 days per cm. Conclusions: A combination of intramedullary nailing along with external fixation significantly reduces external fixation time while maintaining low rate of complications. Great care needs to be taken to prevent pin track infection and deep intramedullary sepsis. PMID:19753160

Tendon transfer fixation: comparing a tendon to tendon technique vs. bioabsorbable interference-fit screw fixation.

PubMed

Sabonghy, Eric Peter; Wood, Robert Michael; Ambrose, Catherine Glauber; McGarvey, William Christopher; Clanton, Thomas Oscar

2003-03-01

Tendon transfer techniques in the foot and ankle are used for tendon ruptures, deformities, and instabilities. This fresh cadaver study compares the tendon fixation strength in 10 paired specimens by performing a tendon to tendon fixation technique or using 7 x 20-25 mm bioabsorbable interference-fit screw tendon fixation technique. Load at failure of the tendon to tendon fixation method averaged 279N (Standard Deviation 81N) and the bioabsorbable screw 148N (Standard Deviation 72N) [p = 0.0008]. Bioabsorbable interference-fit screws in these specimens show decreased fixation strength relative to the traditional fixation technique. However, the mean bioabsorbable screw fixation strength of 148N provides physiologic strength at the tendon-bone interface.

Hinged external fixation of the elbow.

PubMed

Chen, Neal C; Julka, Abhishek

2010-08-01

Hinged external fixation of the elbow provides the advantages of static fixation with the benefits of continued motion through the joint. Indications for the use of this method of fixation include traumatic instability, distraction interposition arthroplasty, instability after contracture release, and instability after excision of heterotopic ossification. Orthopedic surgeons should be familiar with hinged fixators and their application when faced with an unstable ulnohumeral joint. 2010 Elsevier Inc. All rights reserved.

A theoretical analysis and finite element simulation of fixator-bone system stiffness on healing progression.

PubMed

Li, Jianfeng; Zhao, Xia; Hu, Xiaojie; Tao, Chunjing; Ji, Run

2018-03-01

The unilateral external fixator has become a quick and easy application for fracture stabilization of the extremities; the main value for evaluation of mechanical stability of the external fixator is stiffness. The stiffness property of the external fixator affects the local biomechanical environment of fractured bone. In this study, a theoretical model with changing Young's modulus of the callus is established by using the Castigliano's theory, investigating compression stiffness, torsional stiffness and bending stiffness of the fixator-bone system during the healing process. The effects of pin deviation angle on three stiffness methods are also investigated. In addition, finite element simulation is discussed regarding the stress distribution between the fixator and bone. The results reveal the three stiffness evaluation methods are similar for the fixator-bone system. Finite element simulation shows that with increased healing time, the transmission of the load between the fixator and bone are different. In addition, the finite element analyses verify the conclusions obtained from the theoretical model. This work helps orthopedic doctors to monitor the progression of fracture healing and determine the appropriate time for removal of a fixation device and provide important theoretical methodology.

External fixation of tibial pilon fractures and fracture healing.

PubMed

Ristiniemi, Jukka

2007-06-01

Distal tibial fractures are rare and difficult to treat because the bones are subcutaneous. External fixation is commonly used, but the method often results in delayed union. The aim of the present study was to find out the factors that affect fracture union in tibial pilon fractures. For this purpose, prospective data collection of tibial pilon fractures was carried out in 1998-2004, resulting in 159 fractures, of which 83 were treated with external fixation. Additionally, 23 open tibial fractures with significant > 3 cm bone defect that were treated with a staged method in 2000-2004 were retrospectively evaluated. The specific questions to be answered were: What are the risk factors for delayed union associated with two-ring hybrid external fixation? Does human recombinant BMP-7 accelerate healing? What is the role of temporary ankle-spanning external fixation? What is the healing potential of distal tibial bone loss treated with a staged method using antibiotic beads and subsequent autogenous cancellous grafting compared to other locations of the tibia? The following risk factors for delayed healing after external fixation were identified: post-reduction fracture gap of >3 mm and fixation of the associated fibula fracture. Fracture displacement could be better controlled with initial temporary external fixation than with early definitive fixation, but it had no significant effect on healing time, functional outcome or complication rate. Osteoinduction with rhBMP-7 was found to accelerate fracture healing and to shorten the sick leave. A staged method using antibiotic beads and subsequent autogenous cancellous grafting proved to be effective in the treatment of tibial bone loss. Healing potential of the bone loss in distal tibia was at least equally good as in other locations of the tibia.

[Laryngeal Tube Position Shift after Chest Compression: Comparison of Fixation Methods Using Durapore Tape, Multipore Tape, or a Neck Tape].

PubMed

Seno, Hisayo; Komasawa, Nobuyasu; Fujiwara, Shunsuke; Miyazaki, Shinichiro; Tatsumi, Shinichi; Minami, Toshiaki

2015-05-01

The laryngeal tube (LT ; Smiths Medical, Minnesota, U. S. A) is an inflatable supraglottic device for emergency airway management such as during chest compression, the instability after insertion remains a problem. We investigated the effectiveness of three fixation methods of LT using a manikin and automated chest compressor. After 10-minute chest compression, LT without fixation was shifted by 0.4 ± 0.1 cm, which was greater than with Durapore tape (0.2 ± 0.1 cm), Multipore tape (0.2 ± 0.1 cm), or a neck tape (0.1 ± 0.1 cm). The shift of the position was smaller with neck tape fixation compared to Durapore or Multipore tape fixation. A fixation neck tape may be useful in stabilizing the inserted position of LT during cardiopulmonary resuscitation.

Two-stage open reduction and internal fixation versus limited internal fixation combined with external fixation: a meta-analysis of postoperative complications in patients with severe Pilon fractures.

PubMed

Cui, Xueliang; Chen, Hui; Rui, Yunfeng; Niu, Yang; Li, He

2018-01-01

Objectives Two-stage open reduction and internal fixation (ORIF) and limited internal fixation combined with external fixation (LIFEF) are two widely used methods to treat Pilon injury. However, which method is superior to the other remains controversial. This meta-analysis was performed to quantitatively compare two-stage ORIF and LIFEF and clarify which method is better with respect to postoperative complications in the treatment of tibial Pilon fractures. Methods We conducted a meta-analysis to quantitatively compare the postoperative complications between two-stage ORIF and LIFEF. Eight studies involving 360 fractures in 359 patients were included in the meta-analysis. Results The two-stage ORIF group had a significantly lower risk of superficial infection, nonunion, and bone healing problems than the LIFEF group. However, no significant differences in deep infection, delayed union, malunion, arthritis symptoms, or chronic osteomyelitis were found between the two groups. Conclusion Two-stage ORIF was associated with a lower risk of postoperative complications with respect to superficial infection, nonunion, and bone healing problems than LIFEF for tibial Pilon fractures. Level of evidence 2.

Liquid-based cytology and cell block immunocytochemistry in veterinary medicine: comparison with standard cytology for the evaluation of canine lymphoid samples.

PubMed

Fernandes, N C C A; Guerra, J M; Réssio, R A; Wasques, D G; Etlinger-Colonelli, D; Lorente, S; Nogueira, E; Dagli, M L Z

2016-08-01

Liquid-based Cytology (LBC) consists of immediate wet cell fixation with automated slide preparation. We applied LBC, cell block (CB) and immunocytochemistry to diagnose canine lymphoma and compare results with conventional cytology. Samples from enlarged lymph nodes of 18 dogs were collected and fixed in preservative solution for automated slide preparation (LBC), CB inclusion and immunophenotyping. Two CB techniques were tested: fixed sediment method (FSM) and agar method (AM). Anti-CD79a, anti-Pax5, anti-CD3 and anti-Ki67 were used in immunocytochemistry. LBC smears showed better nuclear and nucleolar definition, without cell superposition, but presented smaller cell size and worse cytoplasmic definition. FSM showed consistent cellular groups and were employed for immunocytochemistry, while AM CBs presented sparse groups of lymphocytes, with compromised analysis. Anti-Pax-5 allowed B-cell identification, both in reactive and neoplastic lymph nodes. Our preliminary report suggests that LBC and FSM together may be promising tools to improve lymphoma diagnosis through fine-needle aspiration. © 2015 John Wiley & Sons Ltd.

Biomechanical analysis of titanium fixation plates and screws in sagittal split ramus osteotomies.

PubMed

Atik, F; Atac, M S; Özkan, A; Kılınc, Y; Arslan, M

2016-01-01

The aim of the study was to evaluate the mechanical behavior of three different fixation methods used in the bilateral sagittal split ramus osteotomy. Three different three-dimensional finite element models were created, each corresponding to three different fixation methods. The mandibles were fixed with double straight 4-hole, square 4-hole, and 5-hole Y plates. 150 N incisal occlusal loads were simulated on the distal segments. ANSYS software ((v 10; ANSYS Inc., Canonsburg, PA) was used to calculate the Von Mises stresses on fixative appliances. The highest Von Mises stress values were found in Y plate. The lowest values were isolated in double straight plate group. It was concluded that the use of double 4-hole straight plates provided the sufficient stability on the osteotomy site when compared with the other rigid fixation methods used in this study.

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

Capone, D.G.; Penhale, P.A.; Oremland, R.S.

N/sub 2/ (C/sub 2/H/sub 2/) fixation and primary production were measured in communities of Thalassia testudinum at two sites in Bimini Harbor (Bahamas). Production was determined by uptake of (/sup 14/C)NaHCO/sub 3/, by leaf growth measurements, and by applying an empirical formula based on leaf dimensions. The last two methods gave similar results but the /sup 14/C method gave higher values. Anaerobic sediment N/sub 2/ fixation supplied about 1/4 to 1/2 of the nitrogen demand for leaf production (by leaf growth method) and there was a significant correlation between N/sub 2/ fixation and CO/sub 2/ fixation rates when all componentsmore » of the communities were considered (macrophyte, phyllosphere epiphytes, and detrital leaves). N/sub 2/ fixation is important to production in Thalassia communities and the plant and its leaf epiphytes may be distinct entities in terms of nitrogen and carbon metabolism.« less

Heterophoria and fixation disparity: a review.

PubMed

Kommerell, G; Gerling, J; Ball, M; de Paz, H; Bach, M

2000-06-01

Heterophoria does not provide a reliable clue for ordering prisms in an asthenopic patient. The same reservation applies to associated phoria, as determined by prism correction of fixation disparity. Subjective tests for fixation disparity, even those with a fusionable fixation target, do not correctly indicate the vergence position of the eyes under natural viewing conditions. Attempts to measure fixation disparity on the basis of stereo disparity, using the "Measuring and Correction Methods of H.-J. Haase", have failed.

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness.

PubMed

Mallery, Robert M; Poolman, Pieter; Thurtell, Matthew J; Wang, Jui-Kai; Garvin, Mona K; Ledolter, Johannes; Kardon, Randy H

2016-07-01

The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure-function relationship between fixation and areas of preserved GCC in patients with ON.

Comparison of 39 post-traumatic tibia bone transports performed with and without the use of an intramedullary rod: the long-term outcomes.

PubMed

Liodakis, Emmanouil; Kenawey, Mohamed; Krettek, Christian; Wiebking, Ulrich; Hankemeier, Stefan

2011-09-01

Bone transport can be performed with an external fixator alone or with the monorail technique which entails the combination of a fixator and an intramedullary nail. The purpose of this study was to compare the complication rates and long-term outcomes of these methods. Two groups of patients, the external fixator (n = 21) and the monorail group (n = 18), were compared. The average follow-up period was 7.9 ± 5.6 years and the mean defect length 8.3 ± 3.1 cm. Healing was achieved in 19 (90%) and 13 (72%) of the fixator and monorail patients, respectively. Six patients underwent amputations because of persistent infections (two in the fixator and four in the monorail group). The rate of deformities was significantly higher in the fixator group (p = 0.049). No statistically significant difference was found when comparing categories of the SF-36 test or the ability to work or do sports. The main advantages of the monorail method are reduction of the external fixation time and the lower rate of deformities. However, the authors recommend segmental transport with external fixator in patients with chronic infections.

Biomechanical Comparison Study of Three Fixation Methods for Proximal Chevron Osteotomy of the First Metatarsal in Hallux Valgus

PubMed Central

Kim, Jin Su; Young, Ki Won; Kim, Ji Soo; Lee, Kyung Tai

2017-01-01

Background Fixation of proximal chevron metatarsal osteotomy has been accomplished using K-wires traditionally and with a locking plate recently. However, both methods have many disadvantages. Hence, we developed an intramedullary fixation technique using headless cannulated screws and conducted a biomechanical study to evaluate the superiority of the technique to K-wire and locking plate fixations. Methods Proximal chevron metatarsal osteotomy was performed on 30 synthetic metatarsal models using three fixation techniques. Specimens in group I were fixated with K-wires (1.6 mm × 2) and in group II with headless cannulated screws (3.0 mm × 2) distally through the intramedullary canal. Specimens in group III were fixated with a locking X-shaped plate (1.3-mm thick) and screws (2.5 mm × 4). Eight metatarsal specimens were selected from each group for walking fatigue test. Bending stiffness and dorsal angulation were measured by 1,000 repetitions of a cantilever bending protocol in a plantar to dorsal direction. The remaining two samples from each group were subjected to 5 mm per minute axial loading to assess the maximal loading tolerance. Results All samples in group I failed walking fatigue test while group II and group III tolerated the walking fatigue test. Group II showed greater resistance to bending force and smaller dorsal angulation than group III (p = 0.001). On the axial loading test, group I and group II demonstrated superior maximum tolerance to group III (54.8 N vs. 47.2 N vs. 28.3 N). Conclusions Authors have demonstrated proximal chevron metatarsal osteotomy with intramedullary screw fixation provides superior biomechanical stability to locking plate and K-wire fixations. The new technique using intramedullary screw fixation can offer robust fixation and may lead to better outcomes in surgical treatment of hallux valgus. PMID:29201305

Arthrodesis of the knee following failed arthroplasty.

PubMed

Van Rensch, P J H; Van de Pol, G J; Goosen, J H M; Wymenga, A B; De Man, F H R

2014-08-01

Primary stability in arthrodesis of the knee can be achieved by external fixation, intramedullary nailing or plate fixation. Each method has different features and results. We present a practical algorithm for arthrodesis of the knee following a failed (infected) arthroplasty, based on our own results and a literature review. Between 2004 and 2010, patients were included with an indication for arthrodesis after failed (revision) arthroplasty of the knee. Patients were analyzed with respect to indication, fusion method and bone contact. End-point was solid fusion. Twenty-six arthrodeses were performed. Eighteen patients were treated because of an infected arthroplasty. In total, ten external fixators, ten intramedullary nails and six plate fixations were applied; solid fusion was achieved in 3/10, 8/10 and 3/6, respectively. There is no definite answer as to which method is superior in performing an arthrodesis of the knee. Intramedullary nailing achieved the best fusion rates, but was used most in cases without--or cured--infection. Our data and the contemporary literature suggest that external fixation can be abandoned as standard fusion method, but can be of use following persisting infection. The Ilizarov circular external fixator, however, seems to render high fusion rates. Good patient selection and appropriate individual treatment are the key to a successful arthrodesis. Based upon these findings, a practical algorithm was developed.

Perioperative mortality after hemiarthroplasty related to fixation method.

PubMed

Costain, Darren J; Whitehouse, Sarah L; Pratt, Nicole L; Graves, Stephen E; Ryan, Philip; Crawford, Ross W

2011-06-01

The appropriate fixation method for hemiarthroplasty of the hip as it relates to implant survivorship and patient mortality is a matter of ongoing debate. We examined the influence of fixation method on revision rate and mortality. We analyzed approximately 25,000 hemiarthroplasty cases from the AOA National Joint Replacement Registry. Deaths at 1 day, 1 week, 1 month, and 1 year were compared for all patients and among subgroups based on implant type. Patients treated with cemented monoblock hemiarthroplasty had a 1.7-times higher day-1 mortality compared to uncemented monoblock components (p < 0.001). This finding was reversed by 1 week, 1 month, and 1 year after surgery (p < 0.001). Modular hemiarthroplasties did not reveal a difference in mortality between fixation methods at any time point. This study shows lower (or similar) overall mortality with cemented hemiarthroplasty of the hip.

Is there difference in chronic pain after Suture and Stapler fixation method of mesh in Ventral Hernia? Is stapler fixation method quicker? A randomized controlled trial.

PubMed

Shaukat, Noureen; Jaleel, Farhat; Jawaid, Masood; Zulfiqar, Imrana

2018-01-01

Chronic pain occurs in 20-30% of patients after hernia surgery. As a consequence of this chronic pain, almost one third of patients have limitations in daily activities. Frequency and severity of this pain varies with different techniques of hernia repair. The objective of this study was to compare polypropylene suture and skin staples for securing mesh in uncomplicated ventral hernioplasty in terms of acute and chronic postoperative pain and to compare the time taken for mesh fixation between polypropylene sutures and skin stapler in ventral hernioplasty. This study was conducted in Surgery Department of Dow University Hospital, Dow University of Health Sciences, Ojha Campus and included 53 patients from Jan 2015 to Dec 2016, after taking informed consent. All patients were operated under general anesthesia by the same surgical team. Patients were randomized into two groups; in one group mesh fixed with 2/0 polypropylene suture while in other group mesh stapler was used. Time taken to apply mesh was noted in minutes from laying the mesh over anterior rectus sheath to completion of fixation by either method. The severity of post-operative pain was measured with VAS (1-10) after one week, one month and after one year after surgery. Data was analysed using SPSS version 17. Patient characteristics and operative outcome were similar in the two groups and statistically non-significant in both. Early postoperative pain was more after suture fixation but it was not statistically significant. Mean ± SD pain score was after one week 3.47±2.7 after sutures while 2.91±1.88 after stapler. After four weeks, 0.40±0.49 after suture while 0.35±0.48 after stapler fixation. In both study groups 30-34% of the patients felt some pain in follow-up after one year. Severity of pain was 0.60±0.62 after suture while 1.65±1.94 after stapler fixation which is statistically significant as well (p<0.007). Mean operative time was 15.33±6.33 minutes for suture fixation while 1.56±0.41 minutes for fixation by staples, p-value < 0.001. The method of fixation does not appear to cause significant difference in early post-operative pain but chronic pain is more after stapler fixation of mesh. However, operative time was reduced significantly in staple fixation group as compared to suture fixation group.

Internal Versus External Fixation of Charcot Midfoot Deformity Realignment.

PubMed

Lee, Daniel J; Schaffer, Joseph; Chen, Tien; Oh, Irvin

2016-07-01

Internal and external fixation techniques have been described for realignment and arthrodesis of Charcot midfoot deformity. There currently is no consensus on the optimal method of surgical reconstruction. This systematic review compared the clinical results of surgical realignment with internal and external fixation, specifically in regard to return to functional ambulation, ulcer occurrence, nonunion, extremity amputation, unplanned further surgery, deep infection, wound healing problems, peri- or intraoperative fractures, and total cases with any complication. A search of multiple databases for all relevant articles published from January 1, 1990, to March 22, 2014, was performed. A logistic regression model evaluated each of the outcomes and its association with the type of fixation method. The odds of returning to functional ambulation were 25% higher for internal fixation (odds ratio [OR], 1.259). Internal fixation had a 42% reduced rate of ulcer occurrence (OR, 0.578). External fixation was 8 times more likely to develop radiographic nonunion than internal fixation (OR, 8.2). Internal fixation resulted in a 1.5-fold increase in extremity amputation (OR, 1.488), a 2-fold increase in deep infection (OR, 2.068), a 3.4-fold increase in wound healing complications (OR, 3.405), and a 1.5-fold increase in the total number of cases experiencing any complication (OR, 1.525). This was associated with a 20% increase in the need for unplanned further surgery with internal fixation (OR, 1.221). Although internal fixation may decrease the risk of nonunion and increase return to functional ambulation, it had a higher rate of overall complications than external fixation for realignment and arthrodesis of Charcot midfoot deformity. [Orthopedics. 2016; 39(4):e595-e601.]. Copyright 2016, SLACK Incorporated.

Axial loading screw fixation for chevron type osteotomies of the distal first metatarsal: a retrospective outcomes analysis.

PubMed

Murphy, Ryan M; Fallat, Lawrence M; Kish, John P

2014-01-01

The distal chevron osteotomy is a widely accepted technique for the treatment of hallux abductovalgus deformity. Although the osteotomy is considered to be stable, displacements of the capital fragment has been described. We propose a new method for fixation of the osteotomy involving the axial loading screw (ALS) used in addition to single screw fixation. We believe this method will provide a more mechanically stable construct. We reviewed the charts of 46 patients in whom 52 feet underwent a distal chevron osteotomy that was fixated with either 1 screw or 2 screws that included the ALS. We hypothesized that the ALS group would have fewer displacements and would heal more quickly than the single screw fixation group. We found that the group with ALS fixation had healed at a mean of 6.5 weeks and that the group with single screw fixation had healed at 9.53 weeks (p = .001). Also, 8 cases occurred of displacement of the capital fragment in the single screw, control group compared with 2 cases of displacement in the ALS group. However, this finding was not statistically significant. The addition of the ALS to single screw fixation allowed the patients to heal approximately 3 weeks earlier than single screw fixation alone. The ALS is a fixation option for the surgeon to consider when osseous correction of hallux abducto valgus is performed. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Comparison of a novel fixation device with standard suturing methods for spinal cord stimulators.

PubMed

Bowman, Richard G; Caraway, David; Bentley, Ishmael

2013-01-01

Spinal cord stimulation is a well-established treatment for chronic neuropathic pain of the trunk or limbs. Currently, the standard method of fixation is to affix the leads of the neuromodulation device to soft tissue, fascia or ligament, through the use of manually tying general suture. A novel semiautomated device is proposed that may be advantageous to the current standard. Comparison testing in an excised caprine spine and simulated bench top model was performed. Three tests were performed: 1) perpendicular pull from fascia of caprine spine; 2) axial pull from fascia of caprine spine; and 3) axial pull from Mylar film. Six samples of each configuration were tested for each scenario. Standard 2-0 Ethibond was compared with a novel semiautomated device (Anulex fiXate). Upon completion of testing statistical analysis was performed for each scenario. For perpendicular pull in the caprine spine, the failure load for standard suture was 8.95 lbs with a standard deviation of 1.39 whereas for fiXate the load was 15.93 lbs with a standard deviation of 2.09. For axial pull in the caprine spine, the failure load for standard suture was 6.79 lbs with a standard deviation of 1.55 whereas for fiXate the load was 12.31 lbs with a standard deviation of 4.26. For axial pull in Mylar film, the failure load for standard suture was 10.87 lbs with a standard deviation of 1.56 whereas for fiXate the load was 19.54 lbs with a standard deviation of 2.24. These data suggest a novel semiautomated device offers a method of fixation that may be utilized in lieu of standard suturing methods as a means of securing neuromodulation devices. Data suggest the novel semiautomated device in fact may provide a more secure fixation than standard suturing methods. © 2012 International Neuromodulation Society.

An Overview of Internal and External Fixation Methods for the Diabetic Charcot Foot and Ankle.

PubMed

Ramanujam, Crystal L; Zgonis, Thomas

2017-01-01

Diabetic Charcot neuroarthropathy (DCN) of the foot and ankle is a challenging disease with regard to clinical presentation, pathogenesis, and prognosis. Its surgical management is equally difficult to interpret based on the wide array of options available. In the presence of an ulceration or concomitant osteomyelitis, internal fixation by means of screws, plates, or intramedullary nailing needs to be avoided when feasible. External fixation becomes a great surgical tool when managing DCN with concomitant osteomyelitis. This article describes internal and external fixation methods along with available literature to enlighten surgeons faced with treating this complex condition. Copyright © 2016 Elsevier Inc. All rights reserved.

[Application of polyguanidine solution for fixation of biological and anatomical specimens].

PubMed

Anichkov, N M; Danilova, I A; Riabinin, I A; Kipenko, A V

2010-01-01

A new method for fixation of biological material is described, and its effectiveness is compared to that one of formalin fixation. As an embalming agent, polyhexamethylenguanidine (PHMG) hydrochloride was used. Using the proposed method of fixation, the anatomical and histological preparations of human organs and of chick embryos at developmental 12 days, were produced. The anatomical preparations obtained show the appearance, similar to that of the recently removed organs. Histological preparations were free from significant distortions of the microscopic characteristics of the specimens, which are typical to the material fixed with formalin. The results of the study suggest the possibility of PHMG application in the morphological studies.

[Internal fixation treatment of multiple rib fractures with absorbable rib-connecting-pins under epidural anesthesia].

PubMed

Liu, Jinliang; Li, Keyao; Ju, Zhenlong; Bai, Yan

2011-03-01

To study the indications, methods and experience of absorbable rib-connecting-pins fixation in the treatment of multiple rib fractures. 52 cases with multiple rib fractures were performed internal fixation with absorbable rib-connecting-pins under epidural anesthesia. All cases were followed up for 1 to 12 months, with an average of 5 months. All fractures were achieved healing in 3 to 6 months after the operation and were not found chest wall deformity. Absorbable rib-connecting-pins fixation is a simple and effective method and worthies recommending to perform operation for the appropriate cases with multiple rib fractures.

Clinical results of resection arthrodesis by triangular external fixation for posttraumatic arthrosis of the ankle joint in 89 cases

PubMed Central

2009-01-01

The methods for ankle arthrodesis differ significantly, probably a sign that no method is clearly superior to others. In the last ten years there is a clear favour toward internal fixation. We retrospectively evaluate the technique and evaluate the clinical long term results of external fixation in a triangular frame. Patients and Methods From 1994 to 2001 a consecutive series of 95 patients with end stage arthritis of the ankle joint were treated. Retrospectively the case notes were evaluated regarding trauma history, medical complaints, further injuries and illnesses, walking and pain status and occupational issues and the clinical examination before arthrodesis. Mean age at the index procedure was 45.4 years (18-82), 67 patients were male (70.5%). Via a bilateral approach the malleoli and the joint surfaces were resected. An AO fixator was applied with two Steinmann-nails inserted with approximately 8 cm distance in the distal tibia, one in the neck of the talus and one in the dorsal calcaneus. The fixator was removed after approximately 12 weeks. Follow up examination at mean 4.4 years included a standardised questionnaire and a clinical examination including the criteria of the AOFAS-Score and radiographs. Results: Due to different complications, 8 (8.9%) further surgical procedures were necessary including 1 below knee amputation. In 4 patients a non-union of the ankle arthrodesis developed (4.5%). The mean AOFAS score improved from 20.8 to 69.3 points. Conclusion Non-union rates and clinical results of arthrodesis by triangular external fixation of the ankle joint do not differ to internal fixation methods. The complication rate and the reduced patient comfort reserve this method mainly for infected arthritis and complicated soft tissue situations. PMID:19258207

Short-term N2 fixation kinetics in a moss-associated cyanobacteria.

PubMed

Jean, Marie-Eve; Cassar, Nicolas; Setzer, Cameron; Bellenger, Jean-Philippe

2012-08-21

N(2) fixation by moss-associated cyanobacteria plays an important role in the nitrogen cycling of terrestrial ecosystems. Recent studies have mainly focused on boreal ecosystems; little is known about such association in other ecosystems. Moss-associated cyanobacteria are subject to rapid changes (hourly or less) in environmental conditions that may affect N(2) fixation kinetics. Using a recently developed method (Acetylene Reduction Assays by Cavity ring-down laser Absorption Spectroscopy, ARACAS) with higher sensitivity and sampling frequency than the conventional method, we characterize short-term kinetics of N(2) fixation by cyanobacteria on moss carpets from warm and cold temperate forests. We report the identification of a heretofore unknown multispecies true-moss-cyanobacteria diazotrophic association. We demonstrate that short-term change in abiotic variables greatly influences N(2) fixation. We also show that difference in relative proportion of two epiphytic diazotrophs is consistent with divergent influences of temperature on their N(2) fixation kinetics. Further research is needed to determine whether this difference is consistent with a latitudinal trend.

Rapid microwave fixation of rat mast cells. I. Localization of granule chymase with an ultrastructural postembedding immunogold technique.

PubMed

Login, G R; Galli, S J; Morgan, E; Arizono, N; Schwartz, L B; Dvorak, A M

1987-11-01

We defined the ultrastructural localization of chymase in rat peritoneal mast cells using standard aldehyde fixation and a newly described microwave fixation method (Login GR, Dvorak AM: Microwave energy fixation for electron microscopy. Am J Pathol 120: 230, 1985; Login GR, Stavinoha WB, Dvorak AM: Ultrafast microwave energy fixation for electron microscopy. J Histochem Cytochem 34:381, 1986) and postembedding immunogold labeling. Thin sections were exposed first to goat IgG anti-rat chymase and second to gold-conjugated rabbit Ig directed against goat IgG. By transmission electron microscopy, gold particles were localized to the matrix of cytoplasmic granules. Control sections treated with nonimmune sera did not exhibit labeling of mast cells. Thin sections treated simultaneously with purified rat mast cell chymase and anti-chymase antibody in competition studies, showed a marked reduction in granule staining. These findings demonstrate that a microwave fixation method can be used to rapidly fix cell suspensions for postembedding immunocytochemical studies.

[Automated analysis of bacterial preparations manufactured on automatic heat fixation and staining equipment].

PubMed

2012-01-01

Heat fixation of preparations was made in the fixation bath designed by EMKO (Russia). Programmable "Emkosteiner" (EMKO, Russia) was used for trial staining. Reagents set Micko-GRAM-NITsF was applied for Gram's method of staining. It was demostrated that automatic smear fixation equipment and programmable staining ensure high-quality imaging (1% chromaticity variation) good enough for standardization of Gram's staining of microbial preparations.

Inner ear tissue preservation by rapid freezing: Improving fixation by high-pressure freezing and hybrid methods

PubMed Central

Bullen, A.; Taylor, R.R.; Kachar, B.; Moores, C.; Fleck, R.A.; Forge, A.

2014-01-01

In the preservation of tissues in as ‘close to life’ state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues. PMID:25016142

A new approach to modeling the influence of image features on fixation selection in scenes

PubMed Central

Nuthmann, Antje; Einhäuser, Wolfgang

2015-01-01

Which image characteristics predict where people fixate when memorizing natural images? To answer this question, we introduce a new analysis approach that combines a novel scene-patch analysis with generalized linear mixed models (GLMMs). Our method allows for (1) directly describing the relationship between continuous feature value and fixation probability, and (2) assessing each feature's unique contribution to fixation selection. To demonstrate this method, we estimated the relative contribution of various image features to fixation selection: luminance and luminance contrast (low-level features); edge density (a mid-level feature); visual clutter and image segmentation to approximate local object density in the scene (higher-level features). An additional predictor captured the central bias of fixation. The GLMM results revealed that edge density, clutter, and the number of homogenous segments in a patch can independently predict whether image patches are fixated or not. Importantly, neither luminance nor contrast had an independent effect above and beyond what could be accounted for by the other predictors. Since the parcellation of the scene and the selection of features can be tailored to the specific research question, our approach allows for assessing the interplay of various factors relevant for fixation selection in scenes in a powerful and flexible manner. PMID:25752239

Treatment of transverse patellar fractures: a comparison between metallic and non-metallic implants.

PubMed

Heusinkveld, Maarten H G; den Hamer, Anniek; Traa, Willeke A; Oomen, Pim J A; Maffulli, Nicola

2013-01-01

Several methods of transverse patellar fixation have been described. This study compares the clinical outcome and the occurrence of complications of various fixation methods. The databases PubMed, Web of Science, Science Direct, Google Scholar and Google were searched. A direct comparison between fixation techniques using mixed or non-metallic implants and metallic K-wire and tension band fixation shows no significant difference in clinical outcome between both groups. Additionally, studies reporting novel operation techniques show good clinical results. Studies describing the treatment of patients using non-metallic or mixed implants are fewer compared with those using metallic fixation. A large variety of clinical scoring systems were used for assessing the results of treatment, which makes direct comparison difficult. More data of fracture treatment using non-metallic or mixed implants is needed to achieve a more balanced comparison.

Legume abundance along successional and rainfall gradients in Neotropical forests.

PubMed

Gei, Maga; Rozendaal, Danaë M A; Poorter, Lourens; Bongers, Frans; Sprent, Janet I; Garner, Mira D; Aide, T Mitchell; Andrade, José Luis; Balvanera, Patricia; Becknell, Justin M; Brancalion, Pedro H S; Cabral, George A L; César, Ricardo Gomes; Chazdon, Robin L; Cole, Rebecca J; Colletta, Gabriel Dalla; de Jong, Ben; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan Manuel; Durán, Sandra M; do Espírito Santo, Mário Marcos; Fernandes, G Wilson; Nunes, Yule Roberta Ferreira; Finegan, Bryan; Moser, Vanessa Granda; Hall, Jefferson S; Hernández-Stefanoni, José Luis; Junqueira, André B; Kennard, Deborah; Lebrija-Trejos, Edwin; Letcher, Susan G; Lohbeck, Madelon; Marín-Spiotta, Erika; Martínez-Ramos, Miguel; Meave, Jorge A; Menge, Duncan N L; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Ostertag, Rebecca; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Reich, Peter B; Reyes-García, Casandra; Rodríguez-Velázquez, Jorge; Romero-Pérez, I Eunice; Sanaphre-Villanueva, Lucía; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; de Almeida, Arlete Silva; Almeida-Cortez, Jarcilene S; Silver, Whendee; de Souza Moreno, Vanessa; Sullivan, Benjamin W; Swenson, Nathan G; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria das Dores Magalhães; Vester, Hans F M; Vieira, Ima Célia Guimarães; Zimmerman, Jess K; Powers, Jennifer S

2018-05-28

The nutrient demands of regrowing tropical forests are partly satisfied by nitrogen-fixing legume trees, but our understanding of the abundance of those species is biased towards wet tropical regions. Here we show how the abundance of Leguminosae is affected by both recovery from disturbance and large-scale rainfall gradients through a synthesis of forest inventory plots from a network of 42 Neotropical forest chronosequences. During the first three decades of natural forest regeneration, legume basal area is twice as high in dry compared with wet secondary forests. The tremendous ecological success of legumes in recently disturbed, water-limited forests is likely to be related to both their reduced leaflet size and ability to fix N 2 , which together enhance legume drought tolerance and water-use efficiency. Earth system models should incorporate these large-scale successional and climatic patterns of legume dominance to provide more accurate estimates of the maximum potential for natural nitrogen fixation across tropical forests.

Comparison of the gas-liquid dual support fixation and Heitzman fixation techniques for preparing lung specimens

PubMed Central

Yu, Dongsheng; Qu, Weili; Xia, Haipeng; Li, Xiaofeng; Luan, Zhenfeng; Yan, Renjie; Lu, Xiaodong; Zhao, Peng

2017-01-01

The aim of the present study was to compare the gas-liquid dual support fixation and Heitzman fixation techniques for the preparation of lung specimens. A total of 40 fresh lung samples were surgically collected from 40 male patients with lung cancer by biopsy. Patients were recruited from the Affiliated Hospital of Qingdao University Medical College (Qingdao, China) between July 2007 and June 2014. Samples were prepared using either the gas-liquid dual support fixation method (group A; n=26) or the Heitzman fixation method (group B; n=14). High-resolution computed tomography (HRCT) scanning was performed prior to surgery and corresponding postoperative HRCT scanning was conducted for the lung specimens; the gross transverse specimen section, cord photography images and histological sections were evaluated. Morphological observations of lung specimens indicated that there were 22 cases in group A with grade I (84.6%) and 4 cases with grade II (15.4%), whereas, in group B, there were 5 cases with grade II (35.7%) and 9 cases with grade III (64.3%). Statistical analysis demonstrated that the grades of specimens between the two groups were significantly different (P<0.01). Results from imaging and histological studies found that the quality of lung specimens was superior in group A, compared with group B. In conclusion, the present study demonstrated that, compared with the Heitzman fixation method, gas-liquid dual support fixation may be a superior technique for the preparation of lung specimens. This finding may facilitate the improvement of lung HRCT and pathological studies. PMID:28673006

Monoaxial external fixation of the calcaneus: An anatomical study assessing the safety of monoaxial pin insertion.

PubMed

Thomson, Callum M; Esparon, Tom; Rea, Paul M; Jamal, Bilal

2016-10-01

The use of external fixation for intra-articular calcaneal fractures is increasing in popularity. Studies have shown fine wire and monoaxial external fixation to be a viable surgical alternative to more invasive methods of open reduction and internal fixation of the calcaneus. However, there is an absence of literature that quantifies the risk of pin insertion for monoaxial fixation. This study aimed to determine the safety of inserting monoaxial pins within the calcaneus to house the Orthofix Calcaneal Mini-Fixator. Five formalin embalmed cadaveric ankle and lower leg specimens were inserted with six monoaxial pins. Careful dissection then revealed the presence of the tendons of peroneus longus and brevis, the sural nerve and the small saphenous vein in relation to these pins. Measurements from each pin to each of these structures were made as the structures transected lines drawn from each pin to two palpable bony landmarks: the inferior tip of the lateral malleolus and the posterosuperior calcaneus. In doing this, the risk posed by each pin could be evaluated. We found that two particular pins, those used to hold the articular surface of the subtalar joint in a reduced position, posed a larger risk of injury to surrounding structures than the remaining pins. These findings therefore suggest that monoaxial fixation of the calcaneus using a six pin approach is a relatively safe method of rectifying calcaneal fractures and thus may serve as a welcome alternative to other methods of calcaneal fixation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of the gas-liquid dual support fixation and Heitzman fixation techniques for preparing lung specimens.

PubMed

Yu, Dongsheng; Qu, Weili; Xia, Haipeng; Li, Xiaofeng; Luan, Zhenfeng; Yan, Renjie; Lu, Xiaodong; Zhao, Peng

2017-07-01

The aim of the present study was to compare the gas-liquid dual support fixation and Heitzman fixation techniques for the preparation of lung specimens. A total of 40 fresh lung samples were surgically collected from 40 male patients with lung cancer by biopsy. Patients were recruited from the Affiliated Hospital of Qingdao University Medical College (Qingdao, China) between July 2007 and June 2014. Samples were prepared using either the gas-liquid dual support fixation method (group A; n=26) or the Heitzman fixation method (group B; n=14). High-resolution computed tomography (HRCT) scanning was performed prior to surgery and corresponding postoperative HRCT scanning was conducted for the lung specimens; the gross transverse specimen section, cord photography images and histological sections were evaluated. Morphological observations of lung specimens indicated that there were 22 cases in group A with grade I (84.6%) and 4 cases with grade II (15.4%), whereas, in group B, there were 5 cases with grade II (35.7%) and 9 cases with grade III (64.3%). Statistical analysis demonstrated that the grades of specimens between the two groups were significantly different (P<0.01). Results from imaging and histological studies found that the quality of lung specimens was superior in group A, compared with group B. In conclusion, the present study demonstrated that, compared with the Heitzman fixation method, gas-liquid dual support fixation may be a superior technique for the preparation of lung specimens. This finding may facilitate the improvement of lung HRCT and pathological studies.

Biomechanical Comparison Study of Three Fixation Methods for Proximal Chevron Osteotomy of the First Metatarsal in Hallux Valgus.

PubMed

Kim, Jin Su; Cho, Hun Ki; Young, Ki Won; Kim, Ji Soo; Lee, Kyung Tai

2017-12-01

Fixation of proximal chevron metatarsal osteotomy has been accomplished using K-wires traditionally and with a locking plate recently. However, both methods have many disadvantages. Hence, we developed an intramedullary fixation technique using headless cannulated screws and conducted a biomechanical study to evaluate the superiority of the technique to K-wire and locking plate fixations. Proximal chevron metatarsal osteotomy was performed on 30 synthetic metatarsal models using three fixation techniques. Specimens in group I were fixated with K-wires (1.6 mm × 2) and in group II with headless cannulated screws (3.0 mm × 2) distally through the intramedullary canal. Specimens in group III were fixated with a locking X-shaped plate (1.3-mm thick) and screws (2.5 mm × 4). Eight metatarsal specimens were selected from each group for walking fatigue test. Bending stiffness and dorsal angulation were measured by 1,000 repetitions of a cantilever bending protocol in a plantar to dorsal direction. The remaining two samples from each group were subjected to 5 mm per minute axial loading to assess the maximal loading tolerance. All samples in group I failed walking fatigue test while group II and group III tolerated the walking fatigue test. Group II showed greater resistance to bending force and smaller dorsal angulation than group III ( p = 0.001). On the axial loading test, group I and group II demonstrated superior maximum tolerance to group III (54.8 N vs. 47.2 N vs. 28.3 N). Authors have demonstrated proximal chevron metatarsal osteotomy with intramedullary screw fixation provides superior biomechanical stability to locking plate and K-wire fixations. The new technique using intramedullary screw fixation can offer robust fixation and may lead to better outcomes in surgical treatment of hallux valgus.

Do you see what I see? Mobile eye-tracker contextual analysis and inter-rater reliability.

PubMed

Stuart, S; Hunt, D; Nell, J; Godfrey, A; Hausdorff, J M; Rochester, L; Alcock, L

2018-02-01

Mobile eye-trackers are currently used during real-world tasks (e.g. gait) to monitor visual and cognitive processes, particularly in ageing and Parkinson's disease (PD). However, contextual analysis involving fixation locations during such tasks is rarely performed due to its complexity. This study adapted a validated algorithm and developed a classification method to semi-automate contextual analysis of mobile eye-tracking data. We further assessed inter-rater reliability of the proposed classification method. A mobile eye-tracker recorded eye-movements during walking in five healthy older adult controls (HC) and five people with PD. Fixations were identified using a previously validated algorithm, which was adapted to provide still images of fixation locations (n = 116). The fixation location was manually identified by two raters (DH, JN), who classified the locations. Cohen's kappa correlation coefficients determined the inter-rater reliability. The algorithm successfully provided still images for each fixation, allowing manual contextual analysis to be performed. The inter-rater reliability for classifying the fixation location was high for both PD (kappa = 0.80, 95% agreement) and HC groups (kappa = 0.80, 91% agreement), which indicated a reliable classification method. This study developed a reliable semi-automated contextual analysis method for gait studies in HC and PD. Future studies could adapt this methodology for various gait-related eye-tracking studies.

The effect of two fixation methods (TAF and DESS) on morphometric parameters of Aphelenchoides ritzemabosi.

PubMed

Chałańska, Aneta; Bogumił, Aleksandra; Malewski, Tadeusz; Kowalewska, Katarzyna

2016-02-19

Identification of nematode species by using conventional methods requires fixation of the isolated material and a suitable preparation for further analyses. Tentative identification using microscopic methods should also be performed prior to initiating molecular studies. In the literature, various methods are described for the preparation of nematodes from the genus Aphelenchoides for identification and microscopic studies. The most commonly used fixatives are formalin (Timm 1969; Szczygieł & Cid del Prado Vera 1981, Crozzoli et al. 2008, Khan et al. 2008), FAA (Wasilewska 1969; Vovlas et al. 2005, Khan et al. 2007) and TAF (Hooper 1958, Chizhov et al. 2006, Jagdale & Grewal 2006).

A New Antigen Retrieval Technique for Human Brain Tissue

PubMed Central

Byne, William; Haroutunian, Vahram; García-Villanueva, Mercedes; Rábano, Alberto; García-Amado, María; Prensa, Lucía; Giménez-Amaya, José Manuel

2008-01-01

Immunohistochemical staining of tissues is a powerful tool used to delineate the presence or absence of an antigen. During the last 30 years, antigen visualization in human brain tissue has been significantly limited by the masking effect of fixatives. In the present study, we have used a new method for antigen retrieval in formalin-fixed human brain tissue and examined the effectiveness of this protocol to reveal masked antigens in tissues with both short and long formalin fixation times. This new method, which is based on the use of citraconic acid, has not been previously utilized in brain tissue although it has been employed in various other tissues such as tonsil, ovary, skin, lymph node, stomach, breast, colon, lung and thymus. Thus, we reported here a novel method to carry out immunohistochemical studies in free-floating human brain sections. Since fixation of brain tissue specimens in formaldehyde is a commonly method used in brain banks, this new antigen retrieval method could facilitate immunohistochemical studies of brains with prolonged formalin fixation times. PMID:18852880

Calibration and standardization of microwave ovens for fixation of brain and peripheral nerve tissue.

PubMed

Login, G R; Leonard, J B; Dvorak, A M

1998-06-01

Rapid and reproducible fixation of brain and peripheral nerve tissue for light and electron microscopy studies can be done in a microwave oven. In this review we report a standardized nomenclature for diverse fixation techniques that use microwave heating: (1) microwave stabilization, (2) fast and ultrafast primary microwave-chemical fixation, (3) microwave irradiation followed by chemical fixation, (4) primary chemical fixation followed by microwave irradiation, and (5) microwave fixation used in various combinations with freeze fixation. All of these methods are well suited to fix brain tissue for light microscopy. Fast primary microwave-chemical fixation is best for immunoelectron microscopy studies. We also review how the physical characteristics of the microwave frequency and the dimensions of microwave oven cavities can compromise microwave fixation results. A microwave oven can be calibrated for fixation when the following parameters are standardized: irradiation time; water load volume, initial temperature, and placement within the oven; fixative composition, volume, and initial temperature; and specimen container shape and placement within the oven. Using two recently developed calibration tools, the neon bulb array and the agar-saline-Giemsa tissue phantom, we report a simple calibration protocol that identifies regions within a microwave oven for uniform microwave fixation. Copyright 1998 Academic Press.

History of internal fixation (part 1): early developments with wires and plates before World War II.

PubMed

Hernigou, Philippe; Pariat, Jacques

2017-06-01

Though the date at which an orthopaedic implant was first used cannot be ascertained with any certainty, the fixation of bone fracture using an iron wire was reported for the first time in a French manuscript in 1775. The first techniques of operative fracture treatment were developed at the end of the 18th and in the beginning of the 19th centuries. The use of cerclage wires to fix fractures was the most frequent fixation at this time. The French Berenger-Feraud (1832-1900) had written the first book on internal fixation. However internal fixation of fractures could not become a practical method before Lister had ensured the safety of open reduction and internal fixation in the treatment of fractures. Lister is not only the father of asepsis; he also used metal wires to fix even closed fractures. The first internal fixation by means of a plate and screws was described by Carl Hansmann in 1858 in Hamburg. Nevertheless, Arbuthnot Lane (1892) and Albin Lambotte (1905) are considered to be the founders of this method, which was further developed by Sherman in the first part of the 20th century.

Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI.

PubMed

Henderson, John M; Choi, Wonil; Luke, Steven G; Desai, Rutvik H

2015-10-01

A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading. Copyright © 2015 Elsevier Inc. All rights reserved.

CO2 and soil water potential as regulators of the growth and N fraction derived from fixation of a legume in tallgrass prairie communities

USDA-ARS?s Scientific Manuscript database

CO2 enrichment may increase N input to ecosystems by increasing N2 fixation, but the fixation-CO2 response depends on factors such as soil water availability that are influenced by both CO2 and soil properties. We used the d15N natural abundance method to determine N2 fixation by the legume Desmant...

Modified Goel’s Methods for Basilar Impression: A Case Report with Literature

PubMed Central

Asamoto, Shunji; Fukui, Yasuyuki; Nishiyama, Makoto; Ishikawa, Masayuki; Nakamura, Satoshi; Nagashima, Masaki; Muto, Jun; Jimbo, Hiroyuki

2016-01-01

We report the case of a 57-year-old woman who had basilar impression manifesting as severe myelopathy and occipital neuralgia and was treated by distraction and fixation performed using a modification of Goel’s method. Magnetic resonance imaging (MRI) and computed tomography (CT) scans showed severe myelocompression by the dens of the axis from the ventral side and occipitalization of the atlas. After traction using a Halo vest, C1–2 facet distraction and fixation was performed in one stage using a modified Goel’s method. Although Goel et al. used a custom-made spacer to distract the facet joints, we used a threaded titanium cylindrical cage that was inserted into the joint to fix the C1–2 facet joint with posterior fixation from occipital bone to C5. Postoperatively, gradual symptomatic and neurological amelioration were observed. The atlantoaxial joints were bone-fused at 3 years post-operation. Distraction and fixation performed using this modified version of Goel’s method was effective for treating basilar invagination. The threaded titanium cylindrical cage provided adequate C1–2 space and strong initial fixation. PMID:28663991

Effects of land use and climate change on ecosystem services in Central Asia's arid regions: A case study in Altay Prefecture, China.

PubMed

Fu, Qi; Li, Bo; Hou, Ying; Bi, Xu; Zhang, Xinshi

2017-12-31

The sustainable use of ecosystem services (ES) can contribute to enhancing human well-being. Understanding the effects of land use and climate change on ES can provide scientific and targeted guidance for the sustainable use of ES. The objective of this study was to reveal the way in which land use and climate change influence the spatial and temporal variations of ES in the mountain-oasis-desert system (MODS). In this study, we assessed water yield, soil conservation, crop production, and sand fixation in 1990, 2000, and 2010 in Altay Prefecture, which is representative of the MODS, based on widely used biophysical models. Moreover, we analyzed the effects of different land use and climate change conditions on ES. The results show that the area of forest and bare land decreased in Altay Prefecture. In contrast, the area of grassland with low coverage and cropland increased. The climate of this area presented an overall warming-wetting trend, with warming-drying and cooling-wetting phenomena in some areas. Soil conservation in the mountain zone, water yield in the oasis zone, and sand fixation in the desert zone all decreased under the influence of land use change alone. The warming-drying trend led to decreased water yield in the oasis zone and increased wind erosion in the desert zone. Based on the results, we recommend that local governments achieve sustainable use of ES by planting grasslands with high coverage in the oasis zone, increasing investment in agricultural science and technology, and establishing protected areas in the mountain and desert zones. The methodology in our study can also be applied to other regions with a MODS structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Fixation method does not affect restoration of rotation center in hip replacements: A single-site retrospective study

PubMed Central

2012-01-01

Background Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique. Methods We retrospectively compared pre- and post-operative positions of the hip rotation center in 25 and 68 patients who underwent artificial hip replacements in our department in 2007 using cemented or cementless cup fixation, respectively, with digital radiographic image analysis. Results The mean horizontal and vertical distances between the rotation center and the acetabular teardrop were compared in radiographic images taken pre- and post-operatively. The mean horizontal difference was −2.63 mm (range: -11.00 mm to 10.46 mm, standard deviation 4.23 mm) for patients who underwent cementless fixation, and −2.84 mm (range: -10.87 to 5.30 mm, standard deviation 4.59 mm) for patients who underwent cemented fixation. The mean vertical difference was 0.60 mm (range: -20.15 mm to 10.00 mm, standard deviation 3.93 mm) and 0.41 mm (range: -9.26 mm to 6.54 mm, standard deviation 3.58 mm) for the cementless and cemented fixation groups, respectively. The two fixation techniques had no significant difference on the position of the hip rotation center in the 93 patients in this study. Conclusions The hip rotation center was similarly restored using either the cemented or cementless fixation techniques in this patient cohort, indicating that the fixation technique itself does not interfere with the position of the center of rotation. To completely answer this question further studies with more patients are needed. PMID:22686355

Inner ear tissue preservation by rapid freezing: improving fixation by high-pressure freezing and hybrid methods.

PubMed

Bullen, A; Taylor, R R; Kachar, B; Moores, C; Fleck, R A; Forge, A

2014-09-01

In the preservation of tissues in as 'close to life' state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Skin Graft Fixation Using Hydrofiber (Aquacel® Extra).

PubMed

Yen, Ya-Hui; Lin, Chih-Ming; Hsu, Honda; Chen, Ying-Chen; Chen, Yi-Wen; Li, Wan-Yu; Hsieh, Chia-Nan; Huang, Chieh-Chi

2018-06-01

The traditional method of skin graft fixation is with tie-over bollus dressing. The use of splints in the extremities for skin graft fixation is a common practice. However, these splints are heavy and uncomfortable and contribute considerably to our overall medical waste. Hydrofiber (Aquacel Extra) has a strong fluid absorption property and fixates well to the underlying wound once applied. In this study, we used hydrofiber for fixation, avoiding the use of splints after skin grafting. A total of 56 patients reconstructed with split-thickness skin graft that was fixated only with hydrofiber between March 2015 and March 2016 were included in this retrospective study. There were 44 men and 12 women with a mean age of 61 ± 18 years. The defect size ranged from 1 × 1 cm for fingertips to 30 × 12 cm for lower limb defects. The average defect size was 61 ± 78 cm. The mean skin graft take was 96% ± 6%. Because splints were not required, we saved around 48 kg of medical waste over the space of 1 year. The use of hydrofiber for skin graft fixation was effective and technically very simple. Splints were not required with this method, decreasing the medical waste created and increasing patient comfort. We suggest that this is an excellent alternative for skin graft fixation while at the same time decreasing our carbon footprint as surgeons.

A Comparison of Three Different Methods of Fixation in the Management of Thoracolumbar Fractures.

PubMed

Panteliadis, Pavlos; Musbahi, Omar; Muthian, Senthil; Goyal, Shivam; Montgomery, Alexander Sheriff; Ranganathan, Arun

2017-01-01

Management of thoracolumbar fractures remains controversial in the literature. The primary aims of this study were to assess different levels of fixation with respect to radiological outcomes in terms of fracture reduction and future loss of correction. This is a single center, retrospective study. Fifty-five patients presenting with thoracolumbar fractures between January 2012 and December 2015 were analyzed in the study. The levels of fixation were divided in 3 groups, 1 vertebra above and 1 below the fracture (1/1), 2 above and 2 below (2/2), and 2 above and 1 below (2/1). The most common mechanism was high fall injury and the most common vertebra L1. Burst fractures were the ones with the highest incidence. The 2/2 fixation achieved the best reduction of the fracture but with no statistical significance. The correction is maintained better by the 2/2 fixation but there is no statistical difference compared to the other fixations. Insertion of screws at the fracture level did not improve outcomes. The data of this study identified a trend towards better radiological outcomes for fracture reduction and maintenance of the correction in the 2/2 fixations. However these results are not statistically significant. Future multicenter prospective clinical trials are needed in order to agree on the ideal management and method of fixation for thoracolumbar fractures.

Internal fixation of distal tibiofibular syndesmotic injuries: a systematic review with meta-analysis.

PubMed

Wang, Chen; Ma, Xin; Wang, Xu; Huang, Jiazhang; Zhang, Chao; Chen, Li

2013-09-01

No consensus had been reached about the optimal method for syndesmotic fixation. The present study analysed syndesmotic fixation based on the highest level of clinical evidence in order to obtain more reliable results. Medline, Embase and Cochrane database were searched through the OVID retrieval engine. Manual searching was undertaken afterward to identify additional studies. Only randomized controlled trials (RCT) and prospective comparative studies were selected for final inclusion. Study screening and data extraction were completed independently by two reviewers. All study characteristics were summarized into a table. The extracted data were used for data analysis. Twelve studies were finally included: six of them were RCTs, two were quasi-randomized studies and four were prospective comparative studies. Four comparisons with traditional metallic screw were identified in terms of bioabsorbable screws, tricortical fixation method, suture-button device as well as non-fixation choice in low syndesmotic injuries. Both absorbable screws and the tricortical fixation method showed almost no better results than traditional quadricortical metallic screw (p > 0.05). Additionally, existing studies could not illustrate their efficiency of reducing hardware removal rate. The suture button technique had significantly better functional score (p = 0.003), ankle motion (p = 0.02), time to full weightbearing (p < 0.0001) and much less complications (p = 0.0008) based on short and intermediate term follow-up data. Transfixation in low syndesmotic injuries showed poorer results than the non fixed group in all outcome measurements, but didn't reach a significant level (p > 0.05). The present evidence still couldn't find superior performance of the bioabsorbable screw and tricortical fixation method. Their true effects in decreasing second operation rate need further specific studies. Better results of the suture-button made it a promising technique, but it still needs long-term testing and cost-efficiency studies. The patients with low syndemotic injuries should be well assessed before fixation determination and the indication of screw placement in such conditions needs to be further defined.

Effects of three different preservation methods on the mechanical properties of human and bovine cortical bone.

PubMed

Unger, Stefan; Stefan, Unger; Blauth, Michael; Michael, Blauth; Schmoelz, Werner; Werner, Schmoelz

2010-12-01

In the development of new strategies for fracture fixation, new methods have to be tested biomechanically under in vitro conditions before clinical trials can be performed. The gold standard for laboratory evaluations is fresh-frozen specimen. As the availability of fresh-frozen specimens is limited and since their use bears infectious risks, specimens treated with various chemical embalming fluids are also used. These preservation methods may alter the mechanical properties of the specimens used. Therefore, the aims of the present study were to determine the effects of three different preservation methods (formalin fixation (FO), Thiel-fixation (TH), and alcohol-glycerine fixation (AG)) on the elastic and postyield mechanical properties of cortical bone and to compare these properties to those of fresh-frozen (FF) specimens. Cylindrical cortical specimens (diameter 3mm, length 60 mm) were obtained from human femurs (n=48) and bovine tibiae (n=40). Before specimen immersion in different fixation fluids, bone mineral density (BMD) as well as the initial Young's modulus was determined. The Young's modulus was determined in a nondestructive bending test, and measurements were repeated after 6 months of immersion in fixative solution. Subsequent to the nondestructive test, a destructive 3-point bending test was conducted to assess the postyield and fracture properties. The BMD as well as the initial Young's modulus showed no significant differences between the four test groups. After 6 months in fixative solution, the Young's modulus was significantly lowered in human Thiel specimens and only showed minor changes in formalin- and alcohol-glycerine-treated specimens. The plastic energy absorption of human and bovine specimens was altered significantly. Formalin as well as alcohol-glycerine fixation yielded a significant decrease in plastic energy absorption, whereas Thiel fixation significantly increased the plastic energy absorption. Because of the significantly altered plastic mechanical properties of cortical bone, the use fresh-frozen bone specimens is recommended in biomechanical studies investigating failure loads of orthopaedic implants. The use of embalmed specimens should be restricted to pilot tests. Copyright © 2010 Elsevier Inc. All rights reserved.

The comparative risk of developing postoperative complications in patients with distal radius fractures following different treatment modalities

PubMed Central

Qiu, Wen-Jun; Li, Yi-Fan; Ji, Yun-Han; Xu, Wei; Zhu, Xiao-Dong; Tang, Xian-Zhong; Zhao, Huan-Li; Wang, Gui-Bin; Jia, Yue-Qing; Zhu, Shi-Cai; Zhang, Feng-Fang; Liu, Hong-Mei

2015-01-01

In this study, we performed a network meta-analysis to compare the outcomes of seven most common surgical procedures to fix DRF, including bridging external fixation, non-bridging external fixation, K-wire fixation, plaster fixation, dorsal plating, volar plating, and dorsal and volar plating. Published studies were retrieved through PubMed, Embase and Cochrane Library databases. The database search terms used were the following keywords and MeSH terms: DRF, bridging external fixation, non-bridging external fixation, K-wire fixation, plaster fixation, dorsal plating, volar plating, and dorsal and volar plating. The network meta-analysis was performed to rank the probabilities of postoperative complication risks for the seven surgical modalities in DRF patients. This network meta-analysis included data obtained from a total of 19 RCTs. Our results revealed that compared to DRF patients treated with bridging external fixation, marked differences in pin-track infection (PTI) rate were found in patients treated with plaster fixation, volar plating, and dorsal and volar plating. Cluster analysis showed that plaster fixation is associated with the lowest probability of postoperative complication in DRF patients. Plaster fixation is associated with the lowest risk for postoperative complications in DRF patients, when compared to six other common DRF surgical methods examined. PMID:26549312

Clinical results of resection arthrodesis by triangular external fixation for posttraumatic arthrosis of the ankle joint in 89 cases.

PubMed

Kiene, J; Schulz, Arndt P; Hillbricht, S; Jürgens, Ch; Paech, A

2009-01-28

The methods for ankle arthrodesis differ significantly, probably a sign that no method is clearly superior to others. In the last ten years there is a clear favour toward internal fixation. We retrospectively evaluate the technique and evaluate the clinical long term results of external fixation in a triangular frame. From 1994 to 2001 a consecutive series of 95 patients with end stage arthritis of the ankle joint were treated. Retrospectively the case notes were evaluated regarding trauma history, medical complaints, further injuries and illnesses, walking and pain status and occupational issues and the clinical examination before arthrodesis. Mean age at the index procedure was 45.4 years (18-82), 67 patients were male (70.5%). Via a bilateral approach the malleoli and the joint surfaces were resected. An AO fixator was applied with two Steinmann-nails inserted with approximately 8 cm distance in the distal tibia, one in the neck of the talus and one in the dorsal calcaneus. The fixator was removed after approximately 12 weeks. Follow up examination at mean 4.4 years included a standardised questionnaire and a clinical examination including the criteria of the AOFAS-Score and radiographs. Due to different complications, 8 (8.9%) further surgical procedures were necessary including 1 below knee amputation. In 4 patients a non-union of the ankle arthrodesis developed (4.5%). The mean AOFAS score improved from 20.8 to 69.3 points. Non-union rates and clinical results of arthrodesis by triangular external fixation of the ankle joint do not differ to internal fixation methods. The complication rate and the reduced patient comfort reserve this method mainly for infected arthritis and complicated soft tissue situations.

Automated Cellient(™) cytoblocks: better, stronger, faster?

PubMed

Prendeville, S; Brosnan, T; Browne, T J; McCarthy, J

2014-12-01

Cytoblocks (CBs), or cell blocks, provide additional morphological detail and a platform for immunocytochemistry (ICC) in cytopathology. The Cellient(™) system produces CBs in 45 minutes using methanol fixation, compared with traditional CBs, which require overnight formalin fixation. This study compares Cellient and traditional CB methods in terms of cellularity, morphology and immunoreactivity, evaluates the potential to add formalin fixation to the Cellient method for ICC studies and determines the optimal sectioning depth for maximal cellularity in Cellient CBs. One hundred and sixty CBs were prepared from 40 cytology samples (32 malignant, eight benign) using four processing methods: (A) traditional; (B) Cellient (methanol fixation); (C) Cellient using additional formalin fixation for 30 minutes; (D) Cellient using additional formalin fixation for 60 minutes. Haematoxylin and eosin-stained sections were assessed for cellularity and morphology. ICC was assessed on 14 cases with a panel of antibodies. Three additional Cellient samples were serially sectioned to determine the optimal sectioning depth. Scoring was performed by two independent, blinded reviewers. For malignant cases, morphology was superior with Cellient relative to traditional CBs (P < 0.001). Cellularity was comparable across all methods. ICC was excellent in all groups and the addition of formalin at any stage during the Cellient process did not influence the staining quality. Serial sectioning through Cellient CBs showed optimum cellularity at 30-40 μm with at least 27 sections obtainable. Cellient CBs provide superior morphology to traditional CBs and, if required, formalin fixation may be added to the Cellient process for ICC. Optimal Cellient CB cellularity is achieved at 30-40 μm, which will impact on the handling of cases in daily practice. © 2014 John Wiley & Sons Ltd.

Immunity to human cytomegalovirus measured and compared by complement fixation, indirect fluorescent-antibody, indirect hemagglutination, and enzyme-linked immunosorbent assays.

PubMed Central

Brandt, J A; Kettering, J D; Lewis, J E

1984-01-01

The complement fixation test is currently the test employed most frequently to determine the presence of antibody to human cytomegalovirus. Several other techniques have been adapted for this purpose. A comparison of cytomegalovirus antibody titers was made between the complement fixation test, a commercially available enzyme-linked immunosorbent assay, an indirect immunofluorescent technique, and a modified indirect hemagglutination test. Forty-three serum samples were tested for antibodies by each of the above procedures. The enzyme-linked immunosorbent, immunofluorescent, and indirect hemagglutination assays were in close agreement on all samples tested; the titers obtained with these methods were all equal to or greater than the complement fixation titer for 38 of the 41 samples (92.6%). Two samples were anticomplementary in the complement fixation test but gave readable results in the other tests. The complement fixation test was the least sensitive of the procedures examined. The commercial enzyme-linked immunosorbent assay system was the most practical method and offered the highest degree of sensitivity in detecting antibodies to cytomegalovirus. PMID:6321544

Open reduction and internal fixation compared to closed reduction and external fixation in distal radial fractures

PubMed Central

Kopylov, Philippe; Geijer, Mats; Tägil, Magnus

2009-01-01

Background and purpose In unstable distal radial fractures that are impossible to reduce or to maintain in reduced position, the treatment of choice is operation. The type of operation and the choice of implant, however, is a matter of discussion. Our aim was to investigate whether open reduction and internal fixation would produce a better result than traditional external fixation. Methods 50 patients with an unstable or comminute distal radius fracture were randomized to either closed reduction and bridging external fixation, or open reduction and internal fixation using the TriMed system. The primary outcome parameter was grip strength, but the patients were followed for 1 year with objective clinical assessment, subjective outcome using DASH, and radiographic examination. Results At 1 year postoperatively, grip strength was 90% (SD 16) of the uninjured side in the internal fixation group and 78% (17) in the external fixation group. Pronation/supination was 150° (15) in the internal fixation group and 136° (20) in the external fixation group at 1 year. There were no differences in DASH scores or in radiographic parameters. 5 patients in the external fixation group were reoperated due to malunion, as compared to 1 in the internal fixation group. 7 other cases were classified as radiographic malunion: 5 in the external fixation group and 2 in the internal fixation group. Interpretation Internal fixation gave better grip strength and a better range of motion at 1 year, and tended to have less malunions than external fixation. No difference could be found regarding subjective outcome. PMID:19857180

PECTUS CARINATUM: A NOVEL METHOD OF STERNAL FIXATION.

PubMed

Taha, Assad; Sfeir, Pierre; Al-Taki, Muhyeddine

2016-01-01

The traditional method for fixing the sternum during surgical repair of pectus carinatum is through the use of a stainless steel bar (Adkin’s strut). In this article we describe a new method of sternal fixation using nonabsorbable sutures which are placed in a transverse and crossed fashion anterior to the sternum. This method provides stable sternal fixation and spares the patient a second operation to remove the steel bar. The absence of metallic implants allows clearer view of the thoracic structures in future X-rays, CT scans and MRI, and is likely to be more acceptable to patients than the implantation of a metallic strut in their chest. In addition, it is less costly.

Selection of a rigid internal fixation construct for stabilization at the craniovertebral junction in pediatric patients.

PubMed

Anderson, Richard C E; Ragel, Brian T; Mocco, J; Bohman, Leif-Erik; Brockmeyer, Douglas L

2007-07-01

Atlantoaxial and occipitocervical instability in children have traditionally been treated with posterior bone and wire fusion and external halo orthoses. Recently, successful outcomes have been achieved using rigid internal fixation, particularly C1-2 transarticular screws. The authors describe flow diagrams created to help clinicians determine which method of internal fixation to use in complex anatomical circumstances when bilateral transarticular screw placement is not possible. The records of children who underwent either atlantoaxial or occipitocervical fixation with rigid internal fixation over an 11-year period were retrospectively reviewed to define flow diagrams used to determine treatment protocols. Among the 95 patients identified who underwent atlantoaxial or occipitocervical fixation, the craniocervical anatomy in 25 patients (six atlantoaxial and 19 occipitocervical fixations [26%]) required alternative methods of internal fixation. Types of screw fixation included loop or rod constructs anchored by combinations of C1-2 transarticular screws (15 constructs), C-1 lateral mass screws (11), C-2 pars screws (24), C-2 translaminar screws (one), and subaxial lateral mass screws (six). The mean age of the patients (15 boys and 10 girls) was 9.8 years (range 1.3-17 years). All 22 patients with greater than 3-month follow-up duration achieved solid bone fusion and maintained stable constructs on radiographic studies. Clinical improvement was seen in all patients who had preoperative symptoms. Novel flow diagrams are suggested to help guide selection of rigid internal fixation constructs when performing pediatric C1-2 and occipitocervical stabilizations. Use of these flow diagrams has led to successful fusion in 25 pediatric patients with difficult anatomy requiring less common constructs.

The Trumorph® system: The new universal technique for the observation and analysis of the morphology of living sperm. [corrected].

PubMed

Soler, C; García-Molina, A; Contell, J; Silvestre, M A; Sancho, M

2015-07-01

Evaluation of sperm morphology is a fundamental component of semen analysis, but its real significance has been obscured by a plethora of techniques that involve fixation and staining procedures that induce artefacts. Here we describe Trumorph℗®, a new method for sperm morphology assessment that is based upon examination of wet preparations of living spermatozoa immobilized by a short 60°C shock using negative phase contrast microscopy. We have observed samples from five animals of the following species: bull, boar, goat and rabbit. In every case, all the components of the sperm head and tail were perfectly defined, including the acrosome and midpiece (in all its length, including cytoplasmic droplets). A range of morphological forms was observed, similar to those found by conventional fixed and stained preparations, but other forms were found, distinguishable only by the optics used. The ease of preparation makes it a robust method applicable for analysis of living unmodified spermatozoa in a range of situations. Subsequent studies on well-characterized samples are required to describe the morphology of potentially fertilizing spermatozoa. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of Monolateral External Fixation and Internal Fixation for Skeletal Stabilisation in the Management of Small Tibial Bone Defects following Successful Treatment of Chronic Osteomyelitis

PubMed Central

Wang, Yicun; Jiang, Hui; Deng, Zhantao; Meng, Jia; Wang, Jun

2017-01-01

Background To compare the salvage rate and complication between internal fixation and external fixation in patients with small bone defects caused by chronic infectious osteomyelitis debridement. Methods 125 patients with chronic infectious osteomyelitis of tibia fracture who underwent multiple irrigation, debridement procedure, and local/systemic antibiotics were enrolled. Bone defects, which were less than 4 cm, were treated with bone grafting using either internal fixation or monolateral external fixation. 12-month follow-up was conducted with an interval of 3 months to evaluate union of bone defect. Results Patients who underwent monolateral external fixation had higher body mass index and fasting blood glucose, longer time since injury, and larger bone defect compared with internal fixation. No significant difference was observed in incidence of complications (23.5% versus 19.3%), surgery time (156 ± 23 minutes versus 162 ± 21 minutes), and time to union (11.1 ± 3.0 months versus 10.9 ± 3.1 months) between external fixation and internal fixation. Internal fixation had no significant influence on the occurrence of postoperation complications after multivariate adjustment when compared with external fixation. Furthermore, patients who underwent internal fixation experienced higher level of daily living scales and lower level of anxiety. Conclusions It was relatively safe to use internal fixation for stabilization in osteomyelitis patients whose bone defects were less than 4 cm and infection was well controlled. PMID:29333448

Appraisal of the nitrogen-15 natural-abundance method for quantifying dinitrogen fixation

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

Bremer, E.; van Kessel, C.

Several investigators have questioned the use of the {sup 15}N natural-abundance method of estimating N{sub 2} fixation because of variability in soil {delta}{sup 15}N and small differences between the {delta}{sup 15}N of soil N and atmospheric N. Investigations were conducted to compare the {sup 15}N natural-abundance and {sup 15}N-isotope-dilution methods for estimating N{sub 2} fixation of field-grown pea (Pisum sativum L.) and lentil (Lens culinaris Medik.). Spatial variability was assessed at three sites by determining the {delta}{sup 15}N of non-N{sub 2}-fixing plants. Seasonal variation in {delta}{sup 15}N for spring and winter wheat (Triticum aestivum L.), flax (Linum usitatissimum L.), barleymore » (Hordeum vulgare L.), rape (Brassica napus L.) and lentil was determined at one site. Comparisons between {delta}{sup 15}N and {sup 15}N-enriched isotope-dilution methods for estimating N{sub 2} fixation by lentil were conducted at several sites over a 3-yr period. Variability in {delta}{sup 15}N of the reference plant was site dependent: the {delta}{sup 15}N ranged from 2.8 to 9.3 at the first site, 3.4 to 8.8 at the second site, and 3.5 to 6.2 at the third site. The average {delta}{sup 15}N of four of the five non-N{sub 2}-fixing plants increased from 5.4 at 42 d after planting to 6.9 at the final harvest. The fifth non-N{sub 2}-fixing plant, rape, accumulated most of its N during the first 42 d after planting, and its {delta}{sup 15}N value declined from 8.1 at 42 d after planting to 7.3 at the final harvest. Estimates of N{sub 2} fixation were not significantly different in 18 out of 21 comparisons; in two comparisons in the {delta}{sup 15}N method and in one comparison the {sup 15}N-enriched method provided higher estimates of N{sub 2} fixation. Overall, both methods appeared to provide equally reliable estimates of N{sub 2} fixation for lentil.« less

Tension band suture fixation for olecranon fractures.

PubMed

Phadnis, Joideep; Watts, Adam C

2017-10-01

Olecranon fractures are common and often require surgical treatment when displaced. Traditional methods of stabilization using tension band wire fixation and plate fixation achieve adequate union and function but are associated with a high rate of re-operation and wound problems because of prominent metalwork. The purpose of the present article is to describe an all suture technique for fixation of simple olecranon fractures that maintains inter-fragmentary compression, provides bony union and reduces the rate of re-operation caused by prominent metalwork.

Fixation of silicone stents in the subglottic trachea: preventing stent migration using a fixation apparatus.

PubMed

Miwa, Keisuke; Takamori, Shinzo; Hayashi, Akihiro; Fukunaga, Mari; Shirouzu, Kazuo

2004-12-01

Silicone stents are widely used to treat benign or malignant airway stenosis. However, since straight silicone stents placed into the subglottic trachea to treat stenosis display a high risk of migration, novel approaches are required. The present report outlines our method of external fixation for silicone stents in the subglottic trachea. This technique utilizes a fixation apparatus, is readily performed, and may help to overcome the hesitation seen in placing silicone stents for subglottic tracheal stenosis.

Application of alternative fixatives to formalin in diagnostic pathology

PubMed Central

Gatta, L. Benerini; Cadei, M.; Balzarini, P.; Castriciano, S.; Paroni, R.; Verzeletti, A.; Cortellini, V.; De Ferrari, F.; Grigolato, P.

2012-01-01

Fixation is a critical step in the preparation of tissues for histopathology. The aim of this study was to investigate the effects of different fixatives vs formalin on proteins and DNA, and to evaluate alternative fixation for morphological diagnosis and nucleic acid preservation for molecular methods. Forty tissues were fixed for 24 h with six different fixatives: the gold standard fixative formalin, the historical fixatives Bouin and Hollande, and the alternative fixatives Greenfix, UPM and CyMol. Tissues were stained (Haematoxylin-Eosin, Periodic Acid Schiff, Trichromic, Alcian-blue, High Iron Diamine stainings), and their antigenicity was determined by immunohistochemistry (performed with PAN-CK, CD31, Ki-67, S100, CD68, AML antibodies). DNA extraction, KRAS sequencing, FISH for CEP-17, and flow cytometry analysis of nuclear DNA content were applied. For cell morphology the alternative fixatives (Greenfix, UPM, CyMol) were equivalent to formalin. As expected, Hollande proved to be the best fixative for morphology. The morphology obtained with Bouin was comparable to the one with formalin. Hollande was the best fixative for histochemistry. Bouin proved to be equivalent to formalin. The alternative fixatives were equivalent to formalin, although with greater variability in haematoxylin-eosin staining. It proved the possibility to obtain immunohistochemical staining largely equivalent to that following formalin-fixation with the following fixatives: Greenfix, Hollande, UPM and CyMol. The tissues fixed in Bouin did not provide results comparable to those obtained with formalin. The DNA extracted from samples fixed with alternative fixatives was found to be suitable for molecular analysis. PMID:22688293

Novel Anterior Plating Technique for Patella Fracture Fixation.

PubMed

Siljander, Matthew P; Vara, Alexander D; Koueiter, Denise M; Wiater, Brett P; Wiater, Patrick J

2017-07-01

Patella fracture fixation remains a significant challenge for orthopedic surgeons. Although tension band fixation allows for reliable osseous union, especially in simple fracture patterns, it still presents several problems. Plate fixation of patella fractures is a method that allows for more rigid stabilization and earlier mobilization. At the authors' level 1 trauma center, one fellowship-trained trauma surgeon has transitioned to using a novel anterior, low-profile mesh plate construct for all types of patella fractures. This construct allows for stable fixation, osseous union, and neutralization of the inferior pole for even the most comminuted of patella fractures. [Orthopedics. 2017; 40(4):e739-e743.]. Copyright 2017, SLACK Incorporated.

Modeling fixation locations using spatial point processes.

PubMed

Barthelmé, Simon; Trukenbrod, Hans; Engbert, Ralf; Wichmann, Felix

2013-10-01

Whenever eye movements are measured, a central part of the analysis has to do with where subjects fixate and why they fixated where they fixated. To a first approximation, a set of fixations can be viewed as a set of points in space; this implies that fixations are spatial data and that the analysis of fixation locations can be beneficially thought of as a spatial statistics problem. We argue that thinking of fixation locations as arising from point processes is a very fruitful framework for eye-movement data, helping turn qualitative questions into quantitative ones. We provide a tutorial introduction to some of the main ideas of the field of spatial statistics, focusing especially on spatial Poisson processes. We show how point processes help relate image properties to fixation locations. In particular we show how point processes naturally express the idea that image features' predictability for fixations may vary from one image to another. We review other methods of analysis used in the literature, show how they relate to point process theory, and argue that thinking in terms of point processes substantially extends the range of analyses that can be performed and clarify their interpretation.

Transosseous fixation of pediatric displaced mandibular fractures with polyglactin resorbable suture--a simplified technique.

PubMed

Chandan, Sanjay; Halli, Rajshekhar; Joshi, Samir; Chhabaria, Gaurav; Setiya, Sneha

2013-11-01

Management of pediatric mandibular fractures presents a unique challenge to surgeons in terms of its numerous variations compared to adults. Both conservative and open methods have been advocated with their obvious limitations and complications. However, conservative modalities may not be possible in grossly displaced fractures, which necessitate the open method of fixation. We present a novel and simplified technique of transosseous fixation of displaced pediatric mandibular fractures with polyglactin resorbable suture, which provides adequate stability without any interference with tooth buds and which is easy to master.

Comparing different preparation methods to study human fibrin fibers and platelets using TEM.

PubMed

Buys, Antoinette V; Pretorius, Etheresia

2012-06-01

For the study of cellular ultrastructure, the sample needs to be stabilized by fixation, with the ultimate aim to preserve the native tissue organization and to protect the tissue against later stages of preparation. Chemical and freezing fixation are most used, and chemical fixation employs agents that permeate tissues and cells by diffusion and covalently bind with their major biochemical constituents to fix them. Most widely used chemical fixatives are aldehydes, e.g., formaldehyde and glutaraldehyde, which are noncoagulating, crosslinking agents. Cryofixation methods for ultrastructural studies are also popular, and high-pressure freezing immobilizes all cell constituents and arrests biological activity by removing the thermal energy from the system. In the current research, we used platelet-rich plasma (PRP) to study expansive fibrin fibers and platelet ultrastructure to compare the two fixation techniques. We also used thrombin and calcium chloride as a clotting agent to determine the technique most suitable for the formation of extensive fibrin networks. Chemically fixated fibrin fibers were more compact and condensed and also showed a banding pattern on longitudinal sections. High-pressure frozen samples were more dispersed while platelets fixated showed better preserved cellular membranes and organelle structure. PRP coagulated by addition of CaCl(2) showed blood platelets that are noticeably more activated compared with PRP; however, with thrombin, a sharp ultrastructure was seen. We conclude that PRP mixed with thrombin, and freeze substituted, is the most suitable method for the study of extensive fibrin fibers as well as platelets. Copyright © 2011 Wiley Periodicals, Inc.

Plate fixation versus intramedullary nailing of completely displaced midshaft fractures of the clavicle: a prospective randomised controlled trial.

PubMed

Fuglesang, H F S; Flugsrud, G B; Randsborg, P H; Oord, P; Benth, J Š; Utvåg, S E

2017-08-01

This is a prospective randomised controlled trial comparing the functional outcomes of plate fixation and elastic stable intramedullary nailing (ESIN) of completely displaced mid-shaft fractures of the clavicle in the active adult population. We prospectively recruited 123 patients and randomised them to either plate fixation or ESIN. Patients completed the Quick Disabilities of the Arm, Shoulder and Hand (DASH) score at one to six weeks post-operatively. They were followed up at six weeks, three and six months and one year with radiographs, and their clinical outcome was assessed using both the DASH and the Constant Score. Plate fixation provided a faster functional recovery during the first six months compared with ESIN, but there was no difference after one year. The duration of surgery was shorter for ESIN (mean 53.4 minutes, 22 to 120) than for plate fixation (mean 69.7 minutes, 35 to 106, p < 0.001). The recovery after ESIN was slower with increasing fracture comminution and with open reduction (p < 0.05). Both methods return the patients to their pre-injury functional levels, but plate fixation has a faster recovery period in comminuted fractures than ESIN. ESIN has a shorter operative time and lower infection and implant rates of failure when using 2.5 mm nails or wider, suggesting that this is the preferred method in mid-shaft fractures with no comminution, whereas plate fixation is the superior method in comminuted fractures. Cite this article: Bone Joint J 2017;99-B:1095-1101. ©2017 The British Editorial Society of Bone & Joint Surgery.

The role of fixation and bone quality on the mechanical stability of tibial knee components.

PubMed

Lee, R W; Volz, R G; Sheridan, D C

1991-12-01

Tibial component loosening remains one of the major causes of failure of cemented and noncemented total knee arthroplasties. In this study, the authors identified the role of implant design, method of fixation, and bone density as it related to implant stability. The physical properties of "good" and "bad" bone were simulated using a "good" and "bad" foam model of the proximal tibia, fabricated in the laboratory from DARO RF-100 foam. A generic tibial component permitting various fixation designs was implanted into "good" and "bad" variable density foam tibial models in both cemented and noncemented modes. The mechanical stability of the implants was determined using a Materials Testing Machine by the application of an eccentrically applied cyclic load. The micromotion (subsidence and lift-off) of the tibial implants was recorded using two Linear Variable Differential Transformers. Statistically significant differences in implant stability were recorded as a function of fixation method. The most rigid implant fixation was achieved using four peripherally placed, 6.5-mm cancellous screws. The addition of a central stem added stability only in the case of "poor" quality foam. The mechanical stability of noncemented implants related directly to the density of the foam. Implant stability was greatly enhanced in "poor" quality foam by the use of cement. The method of implant fixation and bone density are critical determinants to tibial implant stability.

[Miniplate internal fixation and autogenous iliac bone graft in surgical treatment of old metatarsal fractures].

PubMed

Pan, Hao; Yu, Guangrong; Xiong, Wen; Zhao, Zhiming; Ding, Fan; Zheng, Qiong; Kan, Wushen

2011-07-01

To summarize the experience of treating old metatarsal fractures with surgery methods of miniplate internal fixation and autogenous iliac bone. Between May 2009 and July 2010, 7 patients with old metatarsal fractures were treated surgically, including 5 multi-metatarsal fractures and 2 single metatarsal fractures. There were 5 males and 2 females aged from 25 to 43 years (mean, 33 years). The time from fracture to operation was 4-12 weeks. The X-ray films showed that a small amount of callus formed at both broken ends with shortening, angulation, or rotation displacement. The surgical treatments included open reduction, internal fixation by miniplate, and autogenous iliac bone graft (1.5-2.5 cm(3)). The external plaster fixation was used in all patients for 4 to 6 weeks postoperatively (mean, 5 weeks). All incisions healed by first intention. The 7 patients were followed up 8-18 months (mean, 13.5 months). The clinical fracture healing time was 6 to 12 weeks postoperatively (mean, 8.4 weeks). No pain of planta pedis occurred while standing and walking. The American Orthopaedic Foot and Ankle Society (AOFAS) mesopedes and propodium score was 75-96 (mean, 86.4). It has the advantages of reliable internal fixation, high fracture healing rate, less complications to treat old metatarsal fractures with surgery methods of miniplate internal fixation and autogenous iliac bone graft, so it is an effective treatment method.

[Complications of open reduction and internal fixation versus external fixation for unstable distal radius fractures: a meta-analysis].

PubMed

Yang, Z; Yuan, Z Z; Ma, J X; Ma, X L

2016-12-20

Objective: To make a systematic assessment of the complications of open reduction and internal fixation versus external fixation for unstable distal radius fractures. Method: A computer-based online search of PubMed, ScienceDirect, EMBASE, BIOSIS, Springer and Cochrane Library were performed.The randomized and controlled trials of open reduction and internal fixation versus external fixation for unstable distal radius fractures were collected.The included trials were screened out strictly based on the criterion of inclusion and exclusion.The quality of included trials was evaluated.RevMan 5.0 was used for data analysis. Result: A total of 17 studies involving 1 402 patients were included.There were 687 patients with open reduction and internal fixation and 715 with external fixation.The results of Meta-analysis indicated that there were statistically significant differences with regard to the postoperatively total complications, infection, malunion, tendon rupture ( I 2 =8%, RR =0.77(95% CI 0.65-0.91, Z =3.10, P <0.05). There were no statistically significant differences observed between two approaches with respect to nounion, re-operation, complex regional pain syndrome, carpal tunnel syndrome, neurapraxia, tendonitis, painful hardware, scar( P >0.05). Conclusion: Postoperative complications are present in both open reduction and internal fixation and external fixation.Compared with external fixation, open reduction and internal fixation is lower in total complications postoperatively, infection and malunion, but external fixation has lower tendon rupture incidence.

Is prophylactic fixation a cost-effective method to prevent a future contralateral fragility hip fracture?

PubMed

Faucett, Scott C; Genuario, James W; Tosteson, Anna N A; Koval, Kenneth J

2010-02-01

: A previous hip fracture more than doubles the risk of a contralateral hip fracture. Pharmacologic and environmental interventions to prevent hip fracture have documented poor compliance. The purpose of this study was to examine the cost-effectiveness of prophylactic fixation of the uninjured hip to prevent contralateral hip fracture. : A Markov state-transition model was used to evaluate the cost and quality-adjusted life-years (QALYs) for unilateral fixation of hip fracture alone (including internal fixation or arthroplasty) compared with unilateral fixation and contralateral prophylactic hip fixation performed at the time of hip fracture or unilateral fixation and bilateral hip pad protection. Prophylactic fixation involved placement of a cephalomedullary nail in the uninjured hip and was initially assumed to have a relative risk of a contralateral fracture of 1%. Health states included good health, surgery-related complications requiring a second operation (infection, osteonecrosis, nonunion, and malunion), fracture of the uninjured hip, and death. The primary outcome measure was the incremental cost-effectiveness ratio estimated as cost per QALY gained in 2006 US dollars with incremental cost-effectiveness ratios below $50,000 per QALY gained considered cost-effective. Sensitivity analyses evaluated the impact of patient age, annual mortality and complication rates, intervention effectiveness, utilities, and costs on the value of prophylactic fixation. : In the baseline analysis, in a 79-year-old woman, prophylactic fixation was not found to be cost-effective (incremental cost-effectiveness ratio = $142,795/QALY). However, prophylactic fixation was found to be a cost-effective method to prevent contralateral hip fracture in: 1) women 71 to 75 years old who had 30% greater relative risk for a contralateral fracture; and 2) women younger than age 70 years. Cost-effectiveness was greater when the additional costs of prophylaxis were less than $6000. However, for most analyses, the success of prophylactic fixation was highly sensitive to the effectiveness and the relative morbidity and mortality of the additional procedure. : Prophylactic fixation with a cephalomedullary nail was not found to be cost-effective for the average older woman who sustained a hip fracture. However, it may be appropriate for select patient populations. The study supports the need for basic science and clinical trials investigating the effectiveness of prophylactic fixation for patient populations at higher lifetime risk for contralateral hip fracture.

Biomechanical analysis of tension band fixation for olecranon fracture treatment.

PubMed

Kozin, S H; Berglund, L J; Cooney, W P; Morrey, B F; An, K N

1996-01-01

This study assessed the strength of various tension band fixation methods with wire and cable applied to simulated olecranon fractures to compare stability and potential failure or complications between the two. Transverse olecranon fractures were simulated by osteotomy. The fracture was anatomically reduced, and various tension band fixation techniques were applied with monofilament wire or multifilament cable. With a material testing machine load displacement curves were obtained and statistical relevance determined by analysis of variance. Two loading modes were tested: loading on the posterior surface of olecranon to simulate triceps pull and loading on the anterior olecranon tip to recreate a potential compressive loading on the fragment during the resistive flexion. All fixation methods were more resistant to posterior loading than to an anterior load. Individual comparative analysis for various loading conditions concluded that tension band fixation is more resilient to tensile forces exerted by the triceps than compressive forces on the anterior olecranon tip. Neither wire passage anterior to the K-wires nor the multifilament cable provided statistically significant increased stability.

Pediatric distal femur fixation by proximal humeral plate.

PubMed

Abdelgawad, Amr Atef; Kanlic, Enes M

2013-12-01

Distal femoral metaphyseal fractures are common injuries in children. Multiple treatment options have been described for this type of injury. For older children with distal metaphyseal fracture, there is still no optimal method of fixation. We propose that the commonly used proximal humeral plate can provide good method of fixation for this fracture in adolescents. Two children (12 and 14 years old) with distal metaphyseal femoral fracture were treated with proximal humeral plate. We describe the surgical technique and postoperative management. The two children healed with good alignment and full range of motion of the knee. No external immobilization (other than knee immobilizer for the first 2 weeks) was used. We concluded that proximal humeral plate can provide adequate fixation for teenagers with distal femoral metaphyseal fracture. It is readily available; provide multiple options for screw fixation in the distal part of the fracture and fits easily on the distal part of the femur proximal to the physis. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Lag screw fixation of anterior mandibular fractures: a retrospective analysis of intraoperative and postoperative complications.

PubMed

Tiwana, Paul S; Kushner, George M; Alpert, Brian

2007-06-01

To review, retrospectively, the outcomes of 102 patients who underwent lag screw technique fixation of fractures of the anterior mandible. A total of 102 consecutive, skeletally mature patients who have undergone open reduction internal fixation for fractures of the anterior mandible utilizing the lag screw technique were reviewed. All patients had a clinically mobile fracture between the mental foramina of the mandible. The patients were followed at usual postoperative intervals with shortest long-term follow-up of 2 months. Intraoperative and long-term postoperative outcomes including status of union, infection, and intraoperative surgical misadventure were recorded. Data from the 102 patients showed that there was 1 fixation failure due to inappropriate patient selection, 1 nonunion requiring bone grafting, 1 with infected screws but with union, 1 with an infected screw and delayed union treated conservatively, and 6 with broken drills from intraoperative surgical misadventures. Lag screw osteosynthesis of anterior mandibular fractures is a sensitive, facile, predictable, and relatively inexpensive method for internal fixation of indicated fractures. As with all methods of rigid internal fixation, most failures or complications are the result of operator judgment or technique.

Femoral Reconstruction Using External Fixation

PubMed Central

Palatnik, Yevgeniy; Rozbruch, S. Robert

2011-01-01

Background. The use of an external fixator for the purpose of distraction osteogenesis has been applied to a wide range of orthopedic problems caused by such diverse etiologies as congenital disease, metabolic conditions, infections, traumatic injuries, and congenital short stature. The purpose of this study was to analyze our experience of utilizing this method in patients undergoing a variety of orthopedic procedures of the femur. Methods. We retrospectively reviewed our experience of using external fixation for femoral reconstruction. Three subgroups were defined based on the primary reconstruction goal lengthening, deformity correction, and repair of nonunion/bone defect. Factors such as leg length discrepancy (LLD), limb alignment, and external fixation time and complications were evaluated for the entire group and the 3 subgroups. Results. There was substantial improvement in the overall LLD, femoral length discrepancy, and limb alignment as measured by mechanical axis deviation (MAD) and lateral distal femoral angle (LDFA) for the entire group as well as the subgroups. Conclusions. The Ilizarov external fixator allows for decreased surgical exposure and preservation of blood supply to bone, avoidance of bone grafting and internal fixation, and simultaneous lengthening and deformity correction, making it a very useful technique for femoral reconstruction. PMID:21991425

External wire-frame fixation of digital skin grafts: a non-invasive alternative to the K-wire insertion method.

PubMed

Huang, Chenyu; Ogawa, Rei; Hyakusoku, Hiko

2014-08-01

The current skin graft fixation methods for digits, including the Kirschner wire insertion technique, can be limited by inadequate or excessive fixation and complications such as infection or secondary injuries. Therefore, the external wire-frame fixation method was invented and used for skin grafting of digits. This study aimed to investigate external wire-frame fixation of digital skin grafts as a non-invasive alternative to the K-wire insertion method. In 2005-2012, 15 patients with burn scar contractures on the hand digits received a skin graft that was then fixed with an external wire frame. The intra-operative time needed to make the wire frame, the postoperative time to frame and suture removal, the graft survival rate, the effect of contracture release and the complications were recorded. In all cases, the contracture release was 100%. The complete graft survival rate was 98.6%. Four patients had epithelial necrosis in <5% of the total area. There were no other complications such as pressure ulcer or hypoxia of fingers. External wire-frame fixation is simple, minimally invasive and a custom-made technique for skin grafting of the fingers. It was designed for its potential benefits and the decreased risk it poses to patients with scar contractures on their fingers. It can be implemented in three phases of grafting, does not affect the epiphyseal line or subsequent finger growth and is suitable for children with multi-digit involvement. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Locking plate fixation provides superior fixation of humerus split type greater tuberosity fractures than tension bands and double row suture bridges.

PubMed

Gaudelli, Cinzia; Ménard, Jérémie; Mutch, Jennifer; Laflamme, G-Yves; Petit, Yvan; Rouleau, Dominique M

2014-11-01

This paper aims to determine the strongest fixation method for split type greater tuberosity fractures of the proximal humerus by testing and comparing three fixation methods: a tension band with No. 2 wire suture, a double-row suture bridge with suture anchors, and a manually contoured calcaneal locking plate. Each method was tested on eight porcine humeri. A osteotomy of the greater tuberosity was performed 50° to the humeral shaft and then fixed according to one of three methods. The humeri were then placed in a testing apparatus and tension was applied along the supraspinatus tendon using a thermoelectric cooling clamp. The load required to produce 3mm and 5mm of displacement, as well as complete failure, was recorded using an axial load cell. The average load required to produce 3mm and 5mm of displacement was 658N and 1112N for the locking plate, 199N and 247N for the double row, and 75N and 105N for the tension band. The difference between the three groups was significant (P<0.01). The average load to failure of the locking plate (810N) was significantly stronger than double row (456N) and tension band (279N) (P<0.05). The stiffness of the locking plate (404N/mm) was significantly greater than double row (71N/mm) and tension band (33N/mm) (P<0.01). Locking plate fixation provides the strongest and stiffest biomechanical fixation for split type greater tuberosity fractures. Copyright © 2014 Elsevier Ltd. All rights reserved.

[The use of negative pressure wound therapy in the fixation of split-thickness skin grafts].

PubMed

Ulianko, J; Janek, J; Laca, Ľ

2017-01-01

Negative pressure wound therapy is one of the latest methods of dealing with complicated healing wounds. It promotes granulation, mechanically attracts the edges of the wound, removes secretions, reduces the number of bacteria in the wound and reduces swelling. In addition to its use to start and enhance the healing process, this method is also important in the fixation of split-thickness skin grafts in non-ideal conditions. The goal of this article is to establish basic indications for negative pressure fixation of meshed split-thickness skin grafts in non-ideal conditions in the wound and to assess the impact of contamination of wounds on engraftment using vacuum therapy. Additional goals are to verify the use of this method of fixation in defects of various etiologies (trauma, ischemia), to optimize and determine the advantages and disadvantages of fixation of grafts using this method in clinical practice, and to evaluate the effectiveness of fixation of meshed split-thickness skin grafts. Set of 89 operated patients of both sexes, various ages, etiologies of defects, in non-ideal conditions; statistical evaluation of the percentage of engraftment, depending on the etiology of the defect, microbial contamination and location of the defect. Measured in vivo using a centimeter measure at the point of maximum length and width. Our set of 100% engraftments of StSG included 68 persons, 65 males and 24 females, in the following age groups: up to 30 years 11 persons; 3050 years 19 persons; 5070 years 38 persons; and above 70 years 21 persons, with negative microbial contamination of the defect in 20 cases, contamination with one germ in 33 cases, contamination with two germs in 22 cases and contamination with three germs in 14 cases. We obtained 100% engraftment in 68 cases, 9099% engraftment in 7 cases, 8089% engraftment in 5 cases, 7079% engraftment in 7 cases, and the 6069% and 5059% sets of engraftment were combined because of the low number of patients in this set. 51 of the patients had a traumatic origin of their defect, 22 had an ischemic origin of their defect and 16 had a different origin of their defect. We found a significant relationship between contamination and the percentage of engraftment, as well as dependence between patient age and the percentage of engraftment. Negative pressure fixation of meshed split-thickness skin grafts seems to be a convenient method of fixation in patients with defects of various origins in non-ideal conditions; this method increases the percentage of engraftment and apparently reduces the time required for fixation of the graft and the length of hospitalisation. We obtained 100% engraftment of StSG using negative pressure fixation. We concluded that traumatic origin had no effect on the percentage of engraftment, while ischemic origin had a significant effect on engraftment. Also, negative contamination of the defect had a positive effect on StSG engraftment, and contamination wit three microbial germs had a significant negative effect on the percentage of StSG engraftment using negative pressure fixation.Key words: negative pressure therapy - NPWT plastic surgery skin grafts complicated wounds.

An ethanol-based fixation method for anatomical and micro-morphological characterization of leaves of various tree species.

PubMed

Chieco, C; Rotondi, A; Morrone, L; Rapparini, F; Baraldi, R

2013-02-01

The use of formalin constitutes serious health hazards for laboratory workers. We investigated the suitability and performance of the ethanol-based fixative, FineFIX, as a substitute for formalin for anatomical and cellular structure investigations of leaves by light microscopy and for leaf surface and ultrastructural analysis by scanning electron microscopy (SEM). We compared the anatomical features of leaf materials prepared using conventional formalin fixation with the FineFIX. Leaves were collected from ornamental tree species commonly used in urban areas. FineFIX was also compared with glutaraldehyde fixation and air drying normally used for scanning electron microscopy to develop a new method for evaluating leaf morphology and microstructure in three ornamental tree species. The cytological features of the samples processed for histological analysis were well preserved by both fixatives as demonstrated by the absence of nuclear swelling or shrinkage, cell wall detachment or tissue flaking, and good presentation of cytoplasmic vacuolization. In addition, good preservation of surface details and the absence of shrinkage artefacts confirmed the efficacy of FineFIX fixation for SEM analysis. Cuticular wax was preserved only in air dried samples. Samples treated with chemical substances during the fixation and dehydration phases showed various alterations of the wax structures. In some air dried samples a loss of turgidity of the cells was observed that caused general wrinkling of the epidermal surfaces. Commercial FineFIX is an adequate substitute for formalin in histology and it can be applied successfully also for SEM investigation, while reducing the health risks of glutaraldehyde or other toxic fixatives. To investigate the potential for plants to absorb and capture particulates in air, which requires preservation of the natural morphology of trichomes and epicuticular waxes, a combination of FineFIX fixation and air drying is recommended.

Fixation probability on clique-based graphs

NASA Astrophysics Data System (ADS)

Choi, Jeong-Ok; Yu, Unjong

2018-02-01

The fixation probability of a mutant in the evolutionary dynamics of Moran process is calculated by the Monte-Carlo method on a few families of clique-based graphs. It is shown that the complete suppression of fixation can be realized with the generalized clique-wheel graph in the limit of small wheel-clique ratio and infinite size. The family of clique-star is an amplifier, and clique-arms graph changes from amplifier to suppressor as the fitness of the mutant increases. We demonstrate that the overall structure of a graph can be more important to determine the fixation probability than the degree or the heat heterogeneity. The dependence of the fixation probability on the position of the first mutant is discussed.

Medial malleolar fractures: a biomechanical study of fixation techniques.

PubMed

Fowler, T Ty; Pugh, Kevin J; Litsky, Alan S; Taylor, Benjamin C; French, Bruce G

2011-08-08

Fracture fixation of the medial malleolus in rotationally unstable ankle fractures typically results in healing with current fixation methods. However, when failure occurs, pullout of the screws from tension, compression, and rotational forces is predictable. We sought to biomechanically test a relatively new technique of bicortical screw fixation for medial malleoli fractures. Also, the AO group recommends tension-band fixation of small avulsion type fractures of the medial malleolus that are unacceptable for screw fixation. A well-documented complication of this technique is prominent symptomatic implants and secondary surgery for implant removal. Replacing stainless steel 18-gauge wire with FiberWire suture could theoretically decrease symptomatic implants. Therefore, a second goal was to biomechanically compare these 2 tension-band constructs. Using a tibial Sawbones model, 2 bicortical screws were compared with 2 unicortical cancellous screws on a servohydraulic test frame in offset axial, transverse, and tension loading. Second, tension-band fixation using stainless steel wire was compared with FiberWire under tensile loads. Bicortical screw fixation was statistically the stiffest construct under tension loading conditions compared to unicortical screw fixation and tension-band techniques with FiberWire or stainless steel wire. In fact, unicortical screw fixation had only 10% of the stiffness as demonstrated in the bicortical technique. In a direct comparison, tension-band fixation using stainless steel wire was statistically stiffer than the FiberWire construct. Copyright 2011, SLACK Incorporated.

Antimicrobial efficacy of external fixator pins coated with a lipid stabilized hydroxyapatite/chlorhexidine complex to prevent pin tract infection in a goat model.

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

Dejong, E. Schuyler; Deberardino, T. M.; Brooks, D. E.

Background: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. Methods: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. Results: Infection developed in 100% of uncoatedmore » pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). Conclusion: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.« less

Bacteria on external fixators: which prep is best?

PubMed

Stinner, Daniel J; Beltran, Michael J; Masini, Brendan D; Wenke, Joseph C; Hsu, Joseph R

2012-03-01

There are no established guidelines for the surgical prep of an external fixator in the operative field. This study investigates the effectiveness of different prep solutions and methods of application. Forty external fixator constructs, consisting of a rod, pin, and pin to rod coupling device, were immersed in a broth of Staphylococcus aureus (lux) for 12 hours. Constructs were then randomized into four treatment groups: chlorhexidine-gluconate (CHG) (4%) scrub, CHG (4%) spray, povidone-iodine (PI) (10%) scrub, and PI (10%) spray. Each construct was imaged with a specialized photon capturing camera system yielding the quantitative and spatial distribution of bacteria both before and after the prep. Each pin to bar clamp was loosened and moved 2 cm down the construct, simulating an external fixator adjustment, and reimaged. Spatial distribution of bacteria and total bacteria counts were compared. There was a similar reduction in bacteria after surgical prep when comparing all four groups independently (p = 0.19), method of application (spray vs. scrub, p = 0.27), and different solutions (CHG vs. PI, p = 0.41). Although bacteria were evident in newly exposed areas after external fixator adjustment, most notably within the loosened pin to bar clamp, it did not result in an increase in bacteria counts (all four groups, p = 0.11; spray vs. scrub, p = 0.18; CHG vs. PI, p = 0.99). Although there was no increase in bacteria counts after the simulated external fixator adjustment, it did expose additional bacteria previously unseen. Although there was no difference in surgical prep solution or method of application, consideration must be given to performing an additional surgical prep of the newly exposed surface after loosening of each individual external fixator component as this may further minimize potential bacteria exposure.

Diagnostic accuracy of eye movements in assessing pedophilia.

PubMed

Fromberger, Peter; Jordan, Kirsten; Steinkrauss, Henrike; von Herder, Jakob; Witzel, Joachim; Stolpmann, Georg; Kröner-Herwig, Birgit; Müller, Jürgen Leo

2012-07-01

Given that recurrent sexual interest in prepubescent children is one of the strongest single predictors for pedosexual offense recidivism, valid and reliable diagnosis of pedophilia is of particular importance. Nevertheless, current assessment methods still fail to fulfill psychometric quality criteria. The aim of the study was to evaluate the diagnostic accuracy of eye-movement parameters in regard to pedophilic sexual preferences. Eye movements were measured while 22 pedophiles (according to ICD-10 F65.4 diagnosis), 8 non-pedophilic forensic controls, and 52 healthy controls simultaneously viewed the picture of a child and the picture of an adult. Fixation latency was assessed as a parameter for automatic attentional processes and relative fixation time to account for controlled attentional processes. Receiver operating characteristic (ROC) analyses, which are based on calculated age-preference indices, were carried out to determine the classifier performance. Cross-validation using the leave-one-out method was used to test the validity of classifiers. Pedophiles showed significantly shorter fixation latencies and significantly longer relative fixation times for child stimuli than either of the control groups. Classifier performance analysis revealed an area under the curve (AUC) = 0.902 for fixation latency and an AUC = 0.828 for relative fixation time. The eye-tracking method based on fixation latency discriminated between pedophiles and non-pedophiles with a sensitivity of 86.4% and a specificity of 90.0%. Cross-validation demonstrated good validity of eye-movement parameters. Despite some methodological limitations, measuring eye movements seems to be a promising approach to assess deviant pedophilic interests. Eye movements, which represent automatic attentional processes, demonstrated high diagnostic accuracy. © 2012 International Society for Sexual Medicine.

Assessing nitrogen fixation in mixed- and single-species plantations of Eucalyptus globulus and Acacia mearnsii.

PubMed

Forrester, David I; Schortemeyer, Marcus; Stock, William D; Bauhus, Jürgen; Khanna, Partap K; Cowie, Annette L

2007-09-01

Mixtures of Eucalyptus globulus Labill. and Acacia mearnsii de Wildeman are twice as productive as E. globulus monocultures growing on the same site in East Gippsland, Victoria, Australia, possibly because of increased nitrogen (N) availability owing to N(2) fixation by A. mearnsii. To investigate whether N(2) fixation by A. mearnsii could account for the mixed-species growth responses, we assessed N(2) fixation by the accretion method and the (15)N natural abundance method. Nitrogen gained by E. globulus and A. mearnsii mixtures and monocultures was calculated by the accretion method with plant and soil samples collected 10 years after plantation establishment. Nitrogen in biomass and soil confirmed that A. mearnsii influenced N dynamics. Assuming that the differences in soil, forest floor litter and biomass N of plots containing A. mearnsii compared with E. globulus monocultures were due to N(2) fixation, the 10-year annual mean rates of N(2) fixation were 38 and 86 kg ha(-1) year(-1) in 1:1 mixtures and A. mearnsii monocultures, respectively. Nitrogen fixation by A. mearnsii could not be quantified on the basis of the natural abundance of (15)N because such factors as mycorrhization type and fractionation of N isotopes during N cycling within the plant confounded the effect of the N source on the N isotopic signature of plants. This study shows that A. mearnsii fixed significant quantities of N(2) when mixed with E. globulus. A decline in delta(15)N values of E. globulus and A. mearnsii with time, from 2 to 10 years, is further evidence that N(2) was fixed and cycled through the stands. The increased aboveground biomass production of E. globulus trees in mixtures when compared with monocultures can be attributed to increases in N availability.

[Finite element study of maxillary Le Fort-I osteotomy with rigid internal fixation].

PubMed

Zhou, Jian; Sun, Geng-Lin; Wu, Wei; Xu, Chong-Tao; Wang, Peng-Lin

2010-05-01

To study the biomechanical characteristic of maxillary Le fort- I osteotomy with rigid internal fixation (RIF) , so as to choose best fixation method. The 3-dimensional finite element models of maxillary Le Fort-I osteotomy with 9 kinds of RIF methods were established. Then the models were divided into three groups to calculate the stress distribution of the maxilla and the displacement of bone segment under 3 kinds of occlusion condition. The fixation stability of the different RIF methods was evaluated. Under the incisor occlusion condition, the stress of the cranio maxillary complex transmits mainly along the nasal-maxillary buttress. Under the premolar and molar occlusion condition, the stress transmits along the alveolar process first, then turns to the nasal-maxillary and zygomatic-maxillary buttress. The focused stress position of the internal fixation system is at the connection between the screws and the plate and at the plate near the osteotomy line. Under the premolar occlusion condition, the displacement of bone segment with different RIF methods was (in a decreasing order) 0.396509 mm (with bio-absorbable plate), 0.148393 mm (with micro-plate ), 0.078436 mm (with mini-plate) in group 1; 0.188791 mm (fixing at the nasal-maxillary buttress), 0.121718 mm (fixing at the zygomatic-maxillary buttress), 0.078436 mm (fixing at the both buttress) in group 2; 0.091023 mm (with straight plate), 0.078436 mm (with L shape plate), 0.072450 mm (with Y shape plate), 0.065617 mm (with T shape plate) in group 3. The fixation stability of using the bio-absorbable plate in Le Fort-I osteotomy is less stable than using the titanium plate. Fixing at the zygomatic-maxillary buttress is more stable than at the naso-maxillary buttress. The fixation stability is different by using different shapes of plates.

Reverse Anterior Cruciate Ligament Reconstruction Fixation: A Biomechanical Comparison Study of Tibial Cross-Pin and Femoral Interference Screw Fixation.

PubMed

Lawley, Richard J; Klein, Samuel E; Chudik, Steven C

2017-03-01

To evaluate the biomechanical performance of tibial cross-pin (TCP) fixation relative to femoral cross-pin (FCP), femoral interference screw (FIS), and tibial interference screw (TIS) fixation. We randomized 40 porcine specimens (20 tibias and 20 femurs) to TIS fixation (group 1, n = 10), FIS fixation (group 2, n = 10), TCP fixation (group 3, n = 10), or FCP fixation (group 4, n = 10) and performed biomechanical testing to compare ultimate load, stiffness, yield load, cyclic displacement, and load at 5-mm displacement. We performed cross-pin fixation of the looped end and interference screw fixation of the free ends of 9-mm-diameter bovine extensor digitorum communis tendon grafts. Graft fixation constructs were cyclically loaded and then loaded to failure in line with the tunnels. Regarding yield load, FIS was superior to TIS (704 ± 125 N vs 504 ± 118 N, P = .002), TCP was superior to TIS (1,449 ± 265 N vs 504 ± 118 N, P < .001), and TCP was superior to FCP (1,449 ± 265 N vs 792 ± 397 N, P < .001). Cyclic displacement for FCP was superior to TCP. Cyclic displacement for TIS versus FIS showed no statistically significant difference (2.5 ± 1.0 mm vs 2.2 ± 0.6 mm, P = .298). Interference screw fixation consistently failed by graft slippage, whereas TCP fixation failed by tibial bone failure. FCP fixation failed by either femoral bone failure or failure elsewhere in the testing apparatus. Regarding yield load, TCP fixation performed biomechanically superior to the clinically proven FCP at time zero. Because TIS fixation shows the lowest yield strength, it represents the weak link, and combined TCP-FIS fixation theoretically would be biomechanically superior relative to combined FCP-TIS fixation with regard to yield load. Cyclic displacement showed a small difference in favor of FCP over TCP fixation and no difference between TIS and FIS. Time-zero biomechanics of TCP fixation paired with FIS fixation show that this method of fixation can be considered a potential alternative to current practice and may pose clinical benefits in different clinical scenarios of anterior cruciate ligament reconstruction. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Suture Button Fixation Versus Syndesmotic Screws in Supination-External Rotation Type 4 Injuries: A Cost-Effectiveness Analysis.

PubMed

Neary, Kaitlin C; Mormino, Matthew A; Wang, Hongmei

2017-01-01

In stress-positive, unstable supination-external rotation type 4 (SER IV) ankle fractures, implant selection for syndesmotic fixation is a debated topic. Among the available syndesmotic fixation methods, the metallic screw and the suture button have been routinely compared in the literature. In addition to strength of fixation and ability to anatomically restore the syndesmosis, costs associated with implant use have recently been called into question. This study aimed to examine the cost-effectiveness of the suture button and determine whether suture button fixation is more cost-effective than two 3.5-mm syndesmotic screws not removed on a routine postoperative basis. Economic and decision analysis; Level of evidence, 2. Studies with the highest evidence levels in the available literature were used to estimate the hardware removal and failure rates for syndesmotic screws and suture button fixation. Costs were determined by examining the average costs for patients who underwent surgery for unstable SER IV ankle fractures at a single level-1 trauma institution. A decision analysis model that allowed comparison of the 2 fixation methods was developed. Using a 20% screw hardware removal rate and a 4% suture button hardware removal rate, the total cost for 2 syndesmotic screws was US$20,836 and the total effectiveness was 5.846. This yielded a total cost of $3564 per quality-adjusted life-year (QALY) over an 8-year time period. The total cost for suture button fixation was $19,354 and the total effectiveness was 5.904, resulting in a total cost of $3294 per QALY over the same time period. A sensitivity analysis was then conducted to assess suture button fixation costs as well as screw and suture button hardware removal rates. Other possible treatment scenarios were also examined, including 1 screw and 2 suture buttons for operative fixation of the syndesmosis. To become more cost-effective, the screw hardware removal rate would have to be reduced to less than 10%. Furthermore, fixation with a single suture button continued to be the dominant treatment strategy compared with 2 suture buttons, 1 screw, and 2 screws for syndesmotic fixation. This cost-effectiveness analysis suggests that for unstable SER IV ankle fractures, suture button fixation is more cost-effective than syndesmotic screws not removed on a routine basis. Suture button fixation was a dominant treatment strategy, because patients spent on average $1482 less and had a higher quality of life by 0.058 QALYs compared with patients who received fixation with 2 syndesmotic screws. Assuming that functional outcomes and failure rates were equivalent, screw fixation only became more cost-effective when the screw hardware removal rate was reduced to less than 10% or when the suture button cost exceeded $2000. In addition, fixation with a single suture button device proved more cost-effective than fixation with either 1 or 2 syndesmotic screws.

A critical analysis of one standard and five methods to monitor surface wetness and time-of-wetness

NASA Astrophysics Data System (ADS)

Camuffo, Dario; della Valle, Antonio; Becherini, Francesca

2018-05-01

Surface wetness is a synergistic factor to determine atmospheric corrosion, monument weathering, mould growth, sick buildings, etc. However, its detection and monitoring are neither easy nor homogeneous, for a number of factors that may affect readings. Various types of methods and sensors, either commercial or prototypes built in the lab, have been investigated and compared, i.e. the international standard ISO 9223 to evaluate corrosivity after wetness and time-of-wetness; indirect evaluation of wetness, based on the dew point calculated after the output of temperature and relative humidity sensors and direct measurements by means of capacitive wetness sensors, safety sensors, rain sensors (also known as leaf wetness sensors), infrared reflection sensors and fibre optic sensors. A comparison between the different methods is presented, specifying physical principles, forms of wetting to which they are respondent (i.e. condensation, ice melting, splashing drops, percolation and capillary rise), critical factors, use and cost.

Long-bone fractures in llamas and alpacas: 28 cases (1998–2008)

PubMed Central

Knafo, S. Emmanuelle; Getman, Liberty M.; Richardson, Dean W.; Fecteau, Marie-Eve

2012-01-01

Treatment and outcome of camelids with long-bone fractures are described. Medical records (1998–2008) of camelids (n = 28) with long-bone fractures were reviewed for signalment, time to presentation, fracture type, method of repair, duration of hospitalization, and post-operative complications. Follow-up information was obtained via telephone interviews with owners. Mean age and weight at presentation were 3.4 years and 56.3 kg, respectively. Twenty-six fractures were treated with internal fixation (n = 11), external fixation (n = 10), combination of internal and external fixation (n = 3), amputation (n = 1), and external fixation followed by amputation (n = 1). Long-term follow-up information was obtained for 19 of the 26 animals. The post-operative complication rate was 23% and owner satisfaction was high. Animals with open fractures were more likely to experience complications. Internal fixation was associated with superior alignment and outcome. Internal fixation techniques should be recommended for camelids. PMID:23277645

Long-bone fractures in llamas and alpacas: 28 cases (1998-2008).

PubMed

Knafo, S Emmanuelle; Getman, Liberty M; Richardson, Dean W; Fecteau, Marie-Eve

2012-07-01

Treatment and outcome of camelids with long-bone fractures are described. Medical records (1998-2008) of camelids (n = 28) with long-bone fractures were reviewed for signalment, time to presentation, fracture type, method of repair, duration of hospitalization, and post-operative complications. Follow-up information was obtained via telephone interviews with owners. Mean age and weight at presentation were 3.4 years and 56.3 kg, respectively. Twenty-six fractures were treated with internal fixation (n = 11), external fixation (n = 10), combination of internal and external fixation (n = 3), amputation (n = 1), and external fixation followed by amputation (n = 1). Long-term follow-up information was obtained for 19 of the 26 animals. The post-operative complication rate was 23% and owner satisfaction was high. Animals with open fractures were more likely to experience complications. Internal fixation was associated with superior alignment and outcome. Internal fixation techniques should be recommended for camelids.

Microwave fixation versus formalin fixation of surgical and autopsy tissue.

PubMed

Login, G R

1978-05-01

Microwave irradiation of surgical and autopsy tissue penetrates, fixes, and hardens the tissue almost immediately (the fluid media used in the microwave consisted of saline, ten percent phosphate buffered formalin, and distilled water). Tissue sections from a representative sample of organs were tested. Comparable sections were simultaneously fixed in a phosphate buffered ten percent formalin bath in a vaccum oven as a control. Hematoxylin and eosin were used to stain the sections. Results equal to and superior to the control method were obtained. Saline microwave fixation was superior to formalin microwave fixation. Tissues placed in Zenker's solution and fixed in standard microwave oven (for approximately one minute) yielded results at least equal to conventional Zenker fixation (approximately two hours). No tissue hardening resulted from Zenker microwave fixation. A unique time versus temperature graph (microwave heating curve) reduces individual variation with this technique.

The lingual splint: an often forgotten method for fixating pediatric mandibular fractures.

PubMed

Binahmed, Abdulaziz; Sansalone, Claudio; Garbedian, Justin; Sándor, George K B

2007-01-01

Maxillofacial fractures are uncommon in the pediatric population, and their treatment is unique due to the psychological, physiological, developmental and anatomical characteristics of children. We present the case of a boy who was treated in an outpatient dental clinic using a lingual splint for the reduction, stabilization and fixation of a mandibular body fracture. This technique is a reliable, noninvasive procedure that dentists may consider in selected cases by referral to an oral and maxillofacial surgeon. It also limits the discomfort and morbidity that can be associated with maxillomandibular fixation or open reduction and internal fixation in pediatric patients.

Fixation of tritium in a highly stable polymer form

DOEpatents

Steinberg, Meyer; Colombo, Peter; Pruzansky, Jacob

1977-01-01

A method for the fixation of tritium comprising reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix.

Computer-assisted virtual preoperative planning in orthopedic surgery for acetabular fractures based on actual computed tomography data.

PubMed

Wang, Guang-Ye; Huang, Wen-Jun; Song, Qi; Qin, Yun-Tian; Liang, Jin-Feng

2016-12-01

Acetabular fractures have always been very challenging for orthopedic surgeons; therefore, appropriate preoperative evaluation and planning are particularly important. This study aimed to explore the application methods and clinical value of preoperative computer simulation (PCS) in treating pelvic and acetabular fractures. Spiral computed tomography (CT) was performed on 13 patients with pelvic and acetabular fractures, and Digital Imaging and Communications in Medicine (DICOM) data were then input into Mimics software to reconstruct three-dimensional (3D) models of actual pelvic and acetabular fractures for preoperative simulative reduction and fixation, and to simulate each surgical procedure. The times needed for virtual surgical modeling and reduction and fixation were also recorded. The average fracture-modeling time was 45 min (30-70 min), and the average time for bone reduction and fixation was 28 min (16-45 min). Among the surgical approaches planned for these 13 patients, 12 were finally adopted; 12 cases used the simulated surgical fixation, and only 1 case used a partial planned fixation method. PCS can provide accurate surgical plans and data support for actual surgeries.

Biomechanical Evaluation of Standard Versus Extended Proximal Fixation Olecranon Plates for Fixation of Olecranon Fractures.

PubMed

Boden, Allison L; Daly, Charles A; Dalwadi, Poonam P; Boden, Stephanie A; Hutton, William C; Muppavarapu, Raghuveer C; Gottschalk, Michael B

2018-01-01

Small olecranon fractures present a significant challenge for fixation, which has resulted in development of plates with proximal extension. Olecranon-specific plates with proximal extensions are widely thought to offer superior fixation of small proximal fragments but have distinct disadvantages: larger dissection, increased hardware prominence, and the increased possibility of impingement. Previous biomechanical studies of olecranon fracture fixation have compared methods of fracture fixation, but to date there have been no studies defining olecranon plate fixation strength for standard versus extended olecranon plates. The purpose of this study is to evaluate the biomechanical utility of the extended plate for treatment of olecranon fractures. Sixteen matched pairs of fresh-frozen human cadaveric elbows were used. Of the 16, 8 matched pairs received a transverse osteotomy including 25% and 8 including 50% of the articular surface on the proximal fragment. One elbow from each pair was randomly assigned to a standard-length plate, and the other elbow in the pair received the extended-length plate, for fixation of the fracture. The ulnae were cyclically loaded and subsequently loaded to failure, with ultimate load, number of cycles, and gap formation recorded. There was no statistically significant difference between the standard and extended fixation plates in simple transverse fractures at either 25% or 50% from the proximal most portion of the articular surface of the olecranon. Standard fixation plates are sufficient for the fixation of small transverse fractures, but caution should be utilized particularly with comminution and nontransverse fracture patterns.

Abnormal Fixational Eye Movements in Amblyopia

PubMed Central

Shaikh, Aasef G.; Otero-Millan, Jorge; Kumar, Priyanka; Ghasia, Fatema F.

2016-01-01

Purpose Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. Methods Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. Results We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. Discussion This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity. PMID:26930079

Fixation Patterns and Reading Rates in Eyes with Central Scotomas from Advanced Atrophic Age-related Macular Degeneration and Stargardt Disease

PubMed Central

Sunness, Janet S.; Applegate, Carol A.; Haselwood, David; Rubin, Gary S.

2009-01-01

Purpose To study fixation patterns and reading rates in eyes with central scotomas from geographic atrophy (GA) of age-related macular degeneration and to compare fixation patterns with those of patients with Stargardt disease. Methods Scanning laser ophthalmoscope analysis of fixation patterns in eyes with 20/80 to 20/200 visual acuity. Included were 41 eyes of 35 patients with GA and 10 eyes of 5 patients with Stargardt disease. The patients with GA also were tested for maximum reading rate, and the size of the areas of atrophy were measured by fundus photograph analysis. Results Sixty-three percent of GA eyes fixating outside the atrophy placed the scotoma to the right of fixation in visual field space, 22% placed the scotoma above fixation, and 15% placed it to the left, regardless of the laterality of the GA eye. Fixation was stable in subsequent years of testing for scotoma placement to the right of or above fixation. All GA eyes fixated immediately adjacent to the atrophy. In contrast, seven of ten eyes with Stargardt disease fixated at a considerable distance from the scotoma border, with the dense scotoma far above the fixation site in visual field space. For the patients with GA, the maximum reading rate was highly correlated with size of the atrophic area, but not with age or visual acuity within the limited visual acuity range tested. There was a trend to more rapid reading with the scotoma above fixation and slower reading with the scotoma to the left. Conclusion There is a preference for fixation with the scotoma to the right in eyes with GA. Patients with Stargardt disease use different strategies for fixation, perhaps due to subclinical pathology adjacent to the atrophic regions. The size of the atrophic area in GA plays the predominant role in reading rate for eyes that have already lost foveal vision. PMID:8841306

Method for wetting a boron alloy to graphite

DOEpatents

Storms, E.K.

1987-08-21

A method is provided for wetting a graphite substrate and spreading a a boron alloy over the substrate. The wetted substrate may be in the form of a needle for an effective ion emission source. The method may also be used to wet a graphite substrate for subsequent joining with another graphite substrate or other metal, or to form a protective coating over a graphite substrate. A noneutectic alloy of boron is formed with a metal selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt) with excess boron, i.e., and atomic percentage of boron effective to precipitate boron at a wetting temperature of less than the liquid-phase boundary temperature of the alloy. The alloy is applied to the substrate and the graphite substrate is then heated to the wetting temperature and maintained at the wetting temperature for a time effective for the alloy to wet and spread over the substrate. The excess boron is evenly dispersed in the alloy and is readily available to promote the wetting and spreading action of the alloy. 1 fig.

Plantar-to-dorsal compared to dorsal-to-plantar screw fixation for proximal chevron osteotomy: a biomechanical analysis.

PubMed

Sharma, Krishn M; Parks, Brent G; Nguyen, Augustine; Schon, Lew C

2005-10-01

A change in screw orientation in fixing the chevron proximal first metatarsal osteotomy was noted anecdotally to improve fixation strength. The authors hypothesized that plantar-to-dorsal screw orientation would be more stable than the conventional dorsal-to-plantar screw orientation for fixation of the chevron osteotomy. The purpose of this study was to determine if the load-to-failure and stiffness of the chevron type proximal first metatarsal osteotomy stabilized using plantar-to-dorsal screw fixation were greater than with the more conventional dorsal-to-plantar screw fixation method. One foot from each of eight matched cadaver pairs was randomly assigned to one of two groups: 1) fixation with a dorsal-to-plantar lag screw or 2) fixation with a plantar-to-dorsal lag screw. A proximal chevron osteotomy was then created using standard technique and the metatarsal was fixed according to previously established method. The bone was potted in polyester resin, and the construct was fitted into a materials testing system machine in which load was applied to the plantar aspect of the metatarsal until failure. The two groups were compared using a two-tailed Student t test. The average load-to-failure and stiffness of the chevron osteotomy fixed with the plantar-to-dorsal lag screw were significantly greater (p < 0.05) than the group fixed with more conventional dorsal-to-plantar lag screws. Plantar-to-dorsal screw orientation was more stable than the conventional dorsal-to-plantar screw orientation for fixation of the proximal chevron osteotomy. Plantar-to-dorsal screw orientation should be considered when using the chevron proximal first metatarsal osteotomy.

Preoperative posterior tilt of at least 20° increased the risk of fixation failure in Garden-I and -II femoral neck fractures.

PubMed

Dolatowski, Filip C; Adampour, Mina; Frihagen, Frede; Stavem, Knut; Erik Utvåg, Stein; Hoelsbrekken, Sigurd Erik

2016-06-01

Background and purpose - It has been suggested that preoperative posterior tilt of the femoral head may increase the risk of fixation failure in Garden-I and -II femoral neck fractures. To investigate this association, we studied a cohort of 322 such patients. Patients and methods - Patients treated with internal fixation between 2005 and 2012 were retrospectively identified using hospital records and the digital image bank. 2 raters measured the preoperative posterior tilt angle and categorized it into 3 groups: < 10°, 10-20°, and ≥ 20°. The inter-rater reliability (IRR) was determined. Patients were observed until September 2013 (with a minimum follow-up of 18 months) or until failure of fixation necessitating salvage arthroplasty. The risk of fixation failure was assessed using competing-risk regression analysis, adjusting for time to surgery. Results - Patients with a posterior tilt of ≥ 20° had a higher risk of fixation failure: 19% (8/43) as compared to 11% (14/127) in the 10-20° category and 6% (9/152) in the < 10° category (p = 0.03). Posterior tilt of ≥ 20° increased the risk of fixation failure, with an adjusted hazard ratio of 3.4 (95% CI: 1.3-8.9; p = 0.01). The interclass correlation coefficient for angular measurements of posterior tilt was 0.90 (95% CI: 0.87-0.92), and the IRR for the categorization of posterior tilt into 3 groups was 0.76 (95% CI: 0.69-0.81). Interpretation - Preoperative posterior tilt of ≥ 20° in Garden-I and -II femoral neck fractures increased the risk of fixation failure necessitating salvage arthroplasty. The reliability of the methods that we used to measure posterior tilt ranged from good to excellent.

Advantages of external hybrid fixators for treating Schatzker V-VI tibial plateau fractures: A retrospective study of 40 cases.

PubMed

Gross, J-B; Gavanier, B; Belleville, R; Coudane, H; Mainard, D

2017-10-01

Proximal tibia fractures make up 1% of all fractures in adults. The fractures classified as Schatzker V and VI fractures can compromise knee structure and function. They are challenging to treat and often have complications. While plate fixation is the gold standard, the resulting infection rate has led us to favor external hybrid fixation. The aims of this study were to assess the radiographic and functional outcomes along with the complication rate when using this method and to compare them to historical plate fixation data. This was a retrospective study of 40 patients. The complications, quality of reduction, IKS, Lysholm and Rasmussen functional scores at the latest follow-up and factors affecting the functional outcome were evaluated. These parameters were compared to published results from plate fixation studies. The deep infection rate was 2.5%. The union rate was 80%. Satisfactory reduction was obtained in 70% of cases; however, 52% of patients had malunion. The mean IKS score was 73.74, the mean Rasmussen score was 22.85 and the mean Lysholm score was 75.53. Age, reduction at latest follow-up, mechanical axis and anteroposterior laxity had a significant effect on the functional outcome. Despite the malunion rate being higher than other studies, the functional outcomes were nearly identical based on the variables measured. There are several advantages associated with using a hybrid external fixator: shorter operative time, less bleeding, shorter hospital stays and lower infection rate. Hybrid external fixation is a reliable fracture fixation method that leads to satisfactory functional outcomes, while reducing the infection rate and allowing arthroplasty to be performed in the future if needed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Detecting fixation on a target using time-frequency distributions of a retinal birefringence scanning signal

PubMed Central

2013-01-01

Background The fovea, which is the most sensitive part of the retina, is known to have birefringent properties, i.e. it changes the polarization state of light upon reflection. Existing devices use this property to obtain information on the orientation of the fovea and the direction of gaze. Such devices employ specific frequency components that appear during moments of fixation on a target. To detect them, previous methods have used solely the power spectrum of the Fast Fourier Transform (FFT), which, unfortunately, is an integral method, and does not give information as to where exactly the events of interest occur. With very young patients who are not cooperative enough, this presents a problem, because central fixation may be present only during very short-lasting episodes, and can easily be missed by the FFT. Method This paper presents a method for detecting short-lasting moments of central fixation in existing devices for retinal birefringence scanning, with the goal of a reliable detection of eye alignment. Signal analysis is based on the Continuous Wavelet Transform (CWT), which reliably localizes such events in the time-frequency plane. Even though the characteristic frequencies are not always strongly expressed due to possible artifacts, simple topological analysis of the time-frequency distribution can detect fixation reliably. Results In all six subjects tested, the CWT allowed precise identification of both frequency components. Moreover, in four of these subjects, episodes of intermittent but definitely present central fixation were detectable, similar to those in Figure 4. A simple FFT is likely to treat them as borderline cases, or entirely miss them, depending on the thresholds used. Conclusion Joint time-frequency analysis is a powerful tool in the detection of eye alignment, even in a noisy environment. The method is applicable to similar situations, where short-lasting diagnostic events need to be detected in time series acquired by means of scanning some substrate along a specific path. PMID:23668264

Soybean nodulation and symbiotic nitrogen fixation in response to soil compaction and mulching

NASA Astrophysics Data System (ADS)

Siczek, A.; Lipiec, J.

2009-04-01

Symbiotic nitrogen fixation by legume crops such as soybean plays a key role in supplying nitrogen for agricultural systems. In symbiotic associations with Bradyrhizobium japonicum soybean can fix up to 200 kg N ha-1 yr-1. This reduces the need for expensive and often environmentally harmful because of leaching nitrogen fertilization. However both soybean nodulation and nitrogen fixation are sensitive to soil conditions. One of the critical soil constraints is soil compaction. Increasing use of heavy equipment and intensive cropping in modern agriculture leads to excessive soil compaction. Compaction often is found as a result of field operations that have to be performed in a very short period of time and when soils are wet and more susceptible to compaction. This results in unfavourable water content, temperature, aeration, pore size distribution, strength for plant growth and microbial activity. The surface mulching can alleviate the adverse effect of the environmental factors on soil by decreasing fluctuation of soil temperature, increasing moisture by controlling evaporation from the soil surface, decreasing bulk density, preventing soil crusting. The effect of mulch on soil conditions largely depends on soil compaction and weather conditions during growing season. The positive effect of the straw mulch on soil moisture has been seen under seasons with insufficient rainfalls. However thicker layers of mulch can act as diffusion barrier, especially when the mulch is wet. Additionally, low soil temperature prevalent during early spring under mulch can impede development of nodule, nodule size and delay onset of nodulation. The aim of this study was to determine the effect of the straw mulch on nodulation and nitrogen fixation of soybean in variously compacted soil. The experimental field was 192 m2and was divided into three parts composed of 6 micro-plots with area 7 m2. Three degrees of soil compaction obtained in each field part through tractor passes were compared: low, medium and heavy (0, 3 or 5 passes, respectively). This resulted in a wide range of soil bulk density (1.2 to 1.65 Mg m-3) that can occur in the arable fields. To obtain uniform conditions for seed germination and initial seedling growth the entire plot area was tilled with a cultivator-harrow to a depth of 5 cm after soil compaction. Soybean "Aldana" seeds inoculated with B. japonicum were sown in rows with spacing of 0.3 m. After sowing half of each micro-plot was mulched with wheat straw (0.5 kg m-2) and another one - not. Nodulation was evaluated by using the parameters of nodule number and nodule weight and acetylene reduction assay was used for the measurement of nitrogenase activity. Number of nodules on root system under mulched and not mulched soil was the highest in not compacted and medium compacted soil, respectively and the lowest - in most compacted soil with mulch. Nitrogenase activity ( mol C2H4 h-1 plant-1) decreased as soil compaction increased but the more pronounced tendency and higher values were obtained in mulched plots. The results indicate that mulching in some range of soil compaction can improve soybean nodulation and nitrogen fixation. This work was funded in part by the Polish Ministry of Science and Higher Education (Grant No N N310 149635).

A new method suitable for calculating accurately wetting temperature over a wide range of conditions: Based on the adaptation of continuation algorithm to classical DFT

NASA Astrophysics Data System (ADS)

Zhou, Shiqi

2017-11-01

A new scheme is put forward to determine the wetting temperature (Tw) by utilizing the adaptation of arc-length continuation algorithm to classical density functional theory (DFT) used originally by Frink and Salinger, and its advantages are summarized into four points: (i) the new scheme is applicable whether the wetting occurs near a planar or a non-planar surface, whereas a zero contact angle method is considered only applicable to a perfectly flat solid surface, as demonstrated previously and in this work, and essentially not fit for non-planar surface. (ii) The new scheme is devoid of an uncertainty, which plagues a pre-wetting extrapolation method and originates from an unattainability of the infinitely thick film in the theoretical calculation. (iii) The new scheme can be similarly and easily applied to extreme instances characterized by lower temperatures and/or higher surface attraction force field, which, however, can not be dealt with by the pre-wetting extrapolation method because of the pre-wetting transition being mixed with many layering transitions and the difficulty in differentiating varieties of the surface phase transitions. (iv) The new scheme still works in instance wherein the wetting transition occurs close to the bulk critical temperature; however, this case completely can not be managed by the pre-wetting extrapolation method because near the bulk critical temperature the pre-wetting region is extremely narrow, and no enough pre-wetting data are available for use of the extrapolation procedure.

Treatment of femoral shaft fractures with monoaxial external fixation in polytrauma patients

PubMed Central

Testa, Gianluca; Aloj, Domenico; Ghirri, Alessandro; Petruccelli, Eraclite; Pavone, Vito; Massé, Alessandro

2017-01-01

Background: Femoral shaft fractures, typical in younger people, are often associated with polytrauma followed by traumatic shock. In these situations, despite intramedullary nailing being the treatment of choice, external fixation could be used as the definitive treatment. The aim of this study is to report evidence regarding definitive treatment of femoral shaft fractures with monoaxial external fixation. Methods: Between January 2006 and December 2015, 83 patients with 87 fractures were treated at the Department of Orthopaedics and Traumatology CTO of Turin, with a monoaxial external fixation device. Mean age at surgery, type of fracture, mean follow-up, time and modalities of treatment, non-weight bearing period, average healing, external fixation removal time, and complications were reported. Results: The average patient age was 31.43±15.19 years. In 37 cases (42.53%) the right femur was involved. 73 (83.91%) fractures were closed, and 14 (16.09%) were open. The average follow-up time was 61.07±21.86 weeks.  In 68 (78.16%) fractures the fixation was carried out in the first 24 hours, using a monoaxial external fixator. In the remaining 19 cases, the average delay was 6.80±4.54 days. Mean non-weight bearing time was 25.82±27.66 days (ranging from 0 to 120). The 87 fractures united at an average of 23.60±11.37 weeks (ranging from 13 to 102). The external fixator was removed after an average of 33.99±14.33 weeks (ranging from 20 to 120). Reported complications included 9.19% of delayed union, 1.15% of septic non-union, 5.75% of malunion, and 8.05% cases of loss of reduction. Conclusions: External fixation of femoral shaft fractures in polytrauma is an ideal method for definitive fracture stabilization, with minimal additional operative trauma and an acceptable complication rate. PMID:28928953

The Biomechanical Properties of Pedicle Screw Fixation Combined With Trajectory Bone Cement Augmentation in Osteoporotic Vertebrae.

PubMed

Fan, Haitao T; Zhang, Renjie J; Shen, Cailiang L; Dong, Fulong L; Li, Yong; Song, Peiwen W; Gong, Chen; Wang, Yijin J

2016-03-01

The biomechanics of pedicle screw fixation combined with trajectory cement augmentation with various filling volumes were measured by pull-out, periodic antibending, and compression fatigue tests. To investigate the biomechanical properties of the pedicle screw fixation combined with trajectory bone cement (polymethylmethacrylate) augmentation in osteoporotic vertebrae and to explore the optimum filling volume of the bone cement. Pedicle screw fixation is considered to be the most effective posterior fixation method. The decrease of the bone mineral density apparently increases the fixation failure risk caused by screw loosening and displacement. Trajectory bone cement augmentation has been confirmed to be an effective method to increase the bone intensity and could markedly increase the stability of the fixation interface. Sixteen elderly cadaveric 1-5 lumbar vertebral specimens were diagnosed with osteoporosis. The left and right vertebral pedicles were alternatively randomized for treatment in all groups, with the contralateral pedicles as control. The study groups included: group A (pedicle screw fixation with full trajectory bone cement augmentation), group B (75% filling), group C (50% filling), and group D (25% filling). Finally, the bone cement leakage and dispersion were assessed and the mechanical testing was conducted. The bone cement was well dispersed around the pedicle screw. The augmented bone intensity, pull-out strength, periodic loading times, and compression fatigue performance were markedly higher than those of the control groups. With the increase in trajectory bone cement, the leakage was also increased (P<0.05). The pull-out strength of the pedicle screw was increased with an increase in bone mineral density and trajectory bone cement. It peaked at 75% filling, with the largest power consumption. The optimal filling volume of the bone cement was 75% of the trajectory volume (about 1.03 mL). The use of excessive bone cement did not increase the fixation intensity but increased the risk of leakage.

Hybrid external fixation in the treatment of tibial pilon fractures: A retrospective analysis of 162 fractures.

PubMed

Galante, Vito N; Vicenti, Giovanni; Corina, Gianfranco; Mori, Claudio; Abate, Antonella; Picca, Girolamo; Conserva, Vito; Speciale, Domenico; Scialpi, Lorenzo; Tartaglia, Nicola; Caiaffa, Vincenzo; Moretti, Biagio

2016-10-01

To determine the efficacy of hybrid external fixation in the treatment of tibial pilon fractures. Retrospective, multicentre study. Adult patients with tibial pilon fractures treated with hybrid external fixation. Fracture reduction with ligamentotaxis and fixation with XCaliber hybrid external fixator. Fracture union, complications, functional outcome (Mazur Ankle Score). Union was obtained in 159 fractures at an average of 125days; there were three delayed unions and three non-unions. The most frequent complication was superficial pin-track infections (48), all of which responded to local wound care and antibiotics. There were no deep infections and no DVT. Only one fracture had loss of reduction that required frame revision. The overall functional scores were 91 (excellent) for AO/OTA type A fractures, 89 (good) for type B fractures, and 75 (satisfactory) for type C fractures. Hybrid external fixation is an effective method of stabilising tibial pilon fractures, particularly those with marked comminution. The minimally-invasive technique and stable fixation enable early mobilisation, with good functional results and minimal complications. Level IV Case series. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbon nanotube fiber spun from wetted ribbon

DOEpatents

Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

2014-04-29

A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

Scanning electron microscopy of bone.

PubMed

Boyde, Alan

2012-01-01

This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

A wet/wet differential pressure sensor for measuring vertical hydraulic gradient.

PubMed

Fritz, Brad G; Mackley, Rob D

2010-01-01

Vertical hydraulic gradient is commonly measured in rivers, lakes, and streams for studies of groundwater-surface water interaction. While a number of methods with subtle differences have been applied, these methods can generally be separated into two categories; measuring surface water elevation and pressure in the subsurface separately or making direct measurements of the head difference with a manometer. Making separate head measurements allows for the use of electronic pressure sensors, providing large datasets that are particularly useful when the vertical hydraulic gradient fluctuates over time. On the other hand, using a manometer-based method provides an easier and more rapid measurement with a simpler computation to calculate the vertical hydraulic gradient. In this study, we evaluated a wet/wet differential pressure sensor for use in measuring vertical hydraulic gradient. This approach combines the advantage of high-temporal frequency measurements obtained with instrumented piezometers with the simplicity and reduced potential for human-induced error obtained with a manometer board method. Our results showed that the wet/wet differential pressure sensor provided results comparable to more traditional methods, making it an acceptable method for future use.

In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.

PubMed

Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

2013-03-01

Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions. Copyright © 2012 Orthopaedic Research Society.

Stabilizing potential of anterior, posterior, and circumferential fixation for multilevel cervical arthrodesis: an in vitro human cadaveric study of the operative and adjacent segment kinematics.

PubMed

Dmitriev, Anton E; Kuklo, Timothy R; Lehman, Ronald A; Rosner, Michael K

2007-03-15

This is an in vitro biomechanical study. The current investigation was performed to evaluate the stabilizing potential of anterior, posterior, and circumferential cervical fixation on operative and adjacent segment motion following 2 and 3-level reconstructions. Previous studies reported increases in adjacent level range of motion (ROM) and intradiscal pressure following single-level cervical arthrodesis; however, no studies have compared adjacent level effects following multilevel anterior versus posterior reconstructions. Ten human cadaveric cervical spines were biomechanically tested using an unconstrained spine simulator under axial rotation, flexion-extension, and lateral bending loading. After intact analysis, all specimens were sequentially instrumented from C3 to C5 with: (1) lateral mass fixation, (2) anterior cervical plate with interbody cages, and (3) combined anterior and posterior fixation. Following biomechanical analysis of 2-level constructs, fixation was extended to C6 and testing repeated. Full ROM was monitored at the operative and adjacent levels, and data normalized to the intact (100%). All reconstructive methods reduced operative level ROM relative to intact specimens under all loading methods (P < 0.05). However, circumferential fixation provided the greatest segmental stability among 2 and 3-level constructs (P < 0.05). Moreover, anterior cervical plate fixation was least efficient at stabilizing operative segments following C3-C6 arthrodesis (P < 0.05). Supradjacent ROM was increased for all treatment groups compared to normal data during flexion-extension testing (P < 0.05). Similar trends were observed under axial rotation and lateral bending loading. At the distal level, flexion-extension and axial rotation testing revealed comparable intergroup differences (P < 0.05), while lateral bending loading indicated greater ROM following 2-level circumferential fixation (P < 0.05). Results from our study revealed greater adjacent level motion following all 3 fixation types. No consistent significant intergroup differences in neighboring segment kinematics were detected among reconstructions. Circumferential fixation provided the greatest level of segmental stability without additional significant increase in adjacent level ROM.

An alternative means of retaining ocular structure and improving immunoreactivity for light microscopy studies

PubMed Central

Sun, Ning; Shibata, Brad; Hess, John F.

2015-01-01

Purpose Several properties of ocular tissue make fixation for light microscopy problematic. Because the eye is spherical, immersion fixation necessarily results in a temporal gradient of fixation, with surfaces fixing more rapidly and thoroughly than interior structures. The problem is compounded by the fact that the layers of the eye wall are compositionally quite different, resulting in different degrees of fixation-induced shrinkage and distortion. Collectively, these result in non-uniform preservation, as well as buckling and/or retinal detachment. This gradient problem is most acute for the lens, where the density of proteins can delay fixation of the central lens for days, and where the fixation gradient parallels the age gradient of lens cells, which complicates data interpretation. Our goal was to identify a simple method for minimizing some of the problems arising from immersion fixation, which avoided covalent modification of antigens, retained high quality structure, and maintained tissue in a state that is amenable to common cytochemical techniques. Methods A simple and inexpensive derivative of the freeze-substitution approach was developed and compared to fixation by immersion in formalin. Preservation of structure, immunoreactivity, GFP and tdTomato fluorescence, lectin reactivity, outer segment auto fluorescence, Click-iT chemistry, compatibility with in situ hybdrdization, and the ability to rehydrate eyes after fixation by freeze substitution for subsequent cryo sectioning were assessed. Results An inexpensive and simple variant of the freeze substitution approach provides excellent structural preservation for light microscopy, and essentially eliminates ocular buckling, retinal detachment, and outer segment auto-fluorescence, without covalent modification of tissue antigens. The approach shows a notable improvement in preservation of immunoreactivity. TdTomato intrinsic fluorescence is also preserved, as is compatibility with in situ hybridization, lectin labeling, and the Click-iT chemistry approach to labeling the thymidine analog EdU. On the negative side, this approach dramatically reduced intrinsic GFP fluorescence. Conclusions A simple, cost-effective derivative of the freeze substitution process is described that is of particular value in the study of rodent or other small eyes, where fixation gradients, globe buckling, retinal detachment, differential shrinkage, autofluorescence, and tissue immunoreactivity have been problematic. PMID:25991907

Effectiveness of wetting method for control of konzo and reduction of cyanide poisoning by removal of cyanogens from cassava flour.

PubMed

Banea, Jean Pierre; Bradbury, J Howard; Mandombi, Chretienne; Nahimana, Damien; Denton, Ian C; Kuwa, N'landa; Tshala Katumbay, D

2014-03-01

Konzo is an irreversible paralysis of the legs that occurs mainly among children and young women in remote villages in tropical Africa and is associated with a monotonous diet of bitter cassava. Konzo was discovered in 1938 by Dr. G. Trolli in the Democratic Republic of Congo (DRC). It also occurs in Mozambique, Tanzania, Cameroon, Central African Republic, and Angola. It was first controlled in Kay Kalenge village, DRC, in 2011 with the use of a wetting method to remove cyanogens from cassava flour. Fourteen months later, another visit was made to Kay Kalenge. To determine whether Kay Kalenge women were still using the wetting method, whether there were new cases of konzo, and whether the wetting method had spread to other villages. Meetings were held with chiefs, leaders, and heads of mothers' groups, women from 30 households were interviewed, and three nearby villages were visited. Total cyanide and thiocyanate were analyzed in cassava flour and urine samples, respectively. The women in Kay Kalenge village still used the wetting method. There were no new cases of konzo. The mean cyanide content of the flour samples was 9 ppm, and no child had a mean urinary thiocyanate content greater than 350 micromol/L. The use of the wetting method had spread naturally to three adjacent villages. The wetting method has been readily accepted by rural women as a simple and useful method to control konzo by removing cyanide from cassava flour, and its use has spread to nearby villages. The wetting method should be promoted by health authorities to control konzo and reduce cyanide poisoning from high-cyanide cassava flour.

Plate versus intramedullary fixation of two-part and multifragmentary displaced midshaft clavicle fractures - a long-term analysis.

PubMed

Chan, Gareth; Korac, Zelimir; Miletic, Matija; Vidovic, Dinko; Phadnis, Joideep; Bakota, Bore

2017-11-01

Surgical fixation of displaced midshaft clavicle fractures is predominantly achieved with intramedullary (IM) or plate fixation. Both techniques have potential pitfalls: plate fixation involves greater periosteal stripping and protuberance of the implant, whereas IM fixation may be associated with implant-related complications, such as migration or skin irritation, which may lead to further surgery for implant removal. The aim of this study was to compare these two methods in simple (Robinson 2b.1) and multifragmentary (Robinson 2b.2) displaced midshaft clavicle fractures. A total of 133 consecutive patients who underwent surgical fixation for a displaced midshaft clavicle fracture with either IM fixation using a 2.5-mm Kirschner wire or plate fixation using an 8-hole Dynamic Compression Plate (DCP) were retrospectively reviewed. Follow-up was a minimum of 1 year. The patients were allocated into two injury groups: displaced simple 2-part fractures (64 IM vs. 16 DCP) and displaced multifragmentary fractures (27 IM vs. 26 DCP). The major observed outcome measures were: infection rate, non-union rate, reoperation rate and postoperative range of motion (ROM). Rates of non-union for displaced 2-part fractures were 2/64 (3.13%) with IM fixation and 0/16 (0.00%) with plate fixation (p = 0.477). For displaced multifragmentary fractures, rates of non-union were 2/27 (7.41%) with IM fixation and 0/26 (0.00%) with plate fixation (p = 0.161). No significant difference was observed between the two fixation modalities in patient-reported time to regain ROM on the injured side for displaced 2-part fractures (p = 0.129) and displaced multifragmentary fractures (p = 0.070). Deep infection rate was zero (p = 1.000) overall in the study, and reoperation rate for IM and plate fixation, respectively, was 3.13% and 6.25% in the Robinson 2b.1 group (p = 0.559) and 7.41% and 7.69% in the Robinson 2b.2 group (p = 0.969). IM fixation of displaced midshaft clavicle fractures (Robinson 2b.1) has an equivalent non-union rate to plate fixation and similarly low complication and reoperation rates. For displaced midshaft multifragmentary clavicle fractures (Robinson 2b.2), the higher non-union rates observed with IM fixation leads us to recommend consideration of plate fixation for Robinson 2b.2 fractures. © 2017 Elsevier Ltd. All rights reserved.

Comparison of Collagen Graft Fixation Methods in the Porcine Knee: Implications for Matrix-Assisted Chondrocyte Implantation and Second-Generation Autologous Chondrocyte Implantation.

PubMed

Whyte, Graeme P; McGee, Alan; Jazrawi, Laith; Meislin, Robert

2016-05-01

To evaluate the fixation integrity at time zero of a type I/III collagen patch secured to a chondral defect in the porcine knee using methods typically employed in autologous chondrocyte implantation (ACI) and matrix-assisted chondrocyte implantation. Twenty-four porcine knee specimens underwent a medial parapatellar arthrotomy. A prefabricated template was used to create cartilage defects of 2 cm(2) in the medial femoral condyle. A size-matched collagen patch was fashioned. Four methods of fixation to the chondral defect were analyzed: group 1-saline, group 2-fibrin glue around the periphery of the patch, group 3-fibrin glue applied to the base of the defect and around the periphery of the patch, group 4-6-0 vicryl suture and fibrin glue around the periphery of the patch. Collagen patch fixation was assessed at intervals of 60, 300, 600, 900, and 1,200 cycles from full extension to 90° of flexion, performed manually without application of axial force. Patch fixation was evaluated by 2 independent observers using a customized scoring scale. Mean peripheral detachment of the patch and chondral defect uncovering remained less than 25% for all groups. Area of defect uncovering was significantly increased in group 2 compared with group 4 after 900 and 1,200 cycles (P = .0014 and P = .0025, respectively). Fibrin glue applied to the base of the defect, or suturing of the patch, reduced deformation significantly after 900 cycles. Suture increases the stability of fixation of a type I/III collagen patch to a chondral defect better than fibrin glue alone in the porcine knee after repetitive cycling, with respect to patch detachment and chondral defect uncovering. Application of fibrin glue to the base of the defect, or securing the patch with suture, decreases collagen patch deformation. In cases where minimally invasive techniques do not allow suture fixation of the collagen patch, scaffold fixation may be compromised during articular motion protocols typically used after second- and third-generation ACI procedures. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Dual Low-Rank Pursuit: Learning Salient Features for Saliency Detection.

PubMed

Lang, Congyan; Feng, Jiashi; Feng, Songhe; Wang, Jingdong; Yan, Shuicheng

2016-06-01

Saliency detection is an important procedure for machines to understand visual world as humans do. In this paper, we consider a specific saliency detection problem of predicting human eye fixations when they freely view natural images, and propose a novel dual low-rank pursuit (DLRP) method. DLRP learns saliency-aware feature transformations by utilizing available supervision information and constructs discriminative bases for effectively detecting human fixation points under the popular low-rank and sparsity-pursuit framework. Benefiting from the embedded high-level information in the supervised learning process, DLRP is able to predict fixations accurately without performing the expensive object segmentation as in the previous works. Comprehensive experiments clearly show the superiority of the proposed DLRP method over the established state-of-the-art methods. We also empirically demonstrate that DLRP provides stronger generalization performance across different data sets and inherits the advantages of both the bottom-up- and top-down-based saliency detection methods.

Calculating Soil Wetness, Evapotranspiration and Carbon Cycle Processes Over Large Grid Areas Using a New Scaling Technique

NASA Technical Reports Server (NTRS)

Sellers, Piers

2012-01-01

Soil wetness typically shows great spatial variability over the length scales of general circulation model (GCM) grid areas (approx 100 km ), and the functions relating evapotranspiration and photosynthetic rate to local-scale (approx 1 m) soil wetness are highly non-linear. Soil respiration is also highly dependent on very small-scale variations in soil wetness. We therefore expect significant inaccuracies whenever we insert a single grid area-average soil wetness value into a function to calculate any of these rates for the grid area. For the particular case of evapotranspiration., this method - use of a grid-averaged soil wetness value - can also provoke severe oscillations in the evapotranspiration rate and soil wetness under some conditions. A method is presented whereby the probability distribution timction(pdf) for soil wetness within a grid area is represented by binning. and numerical integration of the binned pdf is performed to provide a spatially-integrated wetness stress term for the whole grid area, which then permits calculation of grid area fluxes in a single operation. The method is very accurate when 10 or more bins are used, can deal realistically with spatially variable precipitation, conserves moisture exactly and allows for precise modification of the soil wetness pdf after every time step. The method could also be applied to other ecological problems where small-scale processes must be area-integrated, or upscaled, to estimate fluxes over large areas, for example in treatments of the terrestrial carbon budget or trace gas generation.

Partitioning of water flux in a Sierra Nevada ponderosa pine plantation

USGS Publications Warehouse

Kurpius, M.R.; Panek, J.A.; Nikolov, N.T.; McKay, M.; Goldstein, Allen H.

2003-01-01

The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus ponderosa) in this region. To investigate how year-round water fluxes were partitioned in a young ponderosa pine ecosystem in the Sierra Nevada Mountains, water fluxes were continually measured from June 2000 to May 2001 using a combination of sap flow and eddy covariance techniques (above- and below-canopy). Water fluxes were modeled at our study site using a biophysical model, FORFLUX. During summer and fall water fluxes were equally partitioned between transpiration and soil evaporation while transpiration dominated the water fluxes in winter and spring. The trees had high rates of canopy conductance and transpiration in the early morning and mid-late afternoon and a mid-day depression during the dry season. We used a diurnal centroid analysis to show that the timing of high canopy conductance and transpiration relative to high vapor pressure deficit (D) shifted with soil moisture: during periods of low soil moisture canopy conductance and transpiration peaked early in the day when D was low. Conversely, during periods of high soil moisture canopy conductance and transpiration peaked at the same time or later in the day than D. Our observations suggest a general strategy by the pine trees in which they maximize stomatal conductance, and therefore carbon fixation, throughout the day on warm sunny days with high soil moisture (i.e. warm periods in winter and late spring) and maximize stomatal conductance and carbon fixation in the morning through the dry periods. FORFLUX model estimates of evaporation and transpiration were close to measured/calculated values during the dry period, including the drought, but underestimated transpiration and overestimated evaporation during the wet period. ?? 2003 Elsevier Science B.V. All rights reserved.

Temporary and definitive external fixation of war injuries: use of a French dedicated fixator.

PubMed

Mathieu, Laurent; Ouattara, Naklan; Poichotte, Antoine; Saint-Macari, Erwan; Barbier, Olivier; Rongiéras, Fréderic; Rigal, Sylvain

2014-08-01

External fixation is the recommended stabilization method for both open and closed fractures of long bones in forward surgical hospitals. Specific combat surgical tactics are best performed using dedicated external fixators. The Percy Fx (Biomet) fixator was developed for this reason by the French Army Medical Service, and has been used in various theatres of operations for more than ten years. The tactics of Percy Fx (Biomet) fixator use were analysed in two different situations: for the treatment of French soldiers wounded on several battlefields and then evacuated to France and for the management of local nationals in forward medical treatment facilities in Afghanistan and Chad. Overall 48 externals fixators were implanted on 37 French casualties; 28 frames were temporary and converted to definitive rigid frames or internal fixation after medical evacuation. The 77 Afghan patients totalled 85 external fixators, including 13 temporary frames applied in Forward Surgical Teams (FSTs) prior to their arrival at the Kabul combat support hospital. All of the 47 Chadian patients were treated in a FST with primary definitive frames because of delayed surgical management and absence of higher level of care in Chad. Temporary frames were mostly used for French soldiers to facilitate strategic air medical evacuation following trauma damage control orthopaedic principles. Definitive rigid frames permitted achieving treatment of all types of war extremity injuries, even in poor conditions.

A Meta-Analysis for Postoperative Complications in Tibial Plafond Fracture: Open Reduction and Internal Fixation Versus Limited Internal Fixation Combined With External Fixator.

PubMed

Wang, Dong; Xiang, Jian-Ping; Chen, Xiao-Hu; Zhu, Qing-Tang

2015-01-01

The treatment of tibial plafond fractures is challenging to foot and ankle surgeons. Open reduction and internal fixation and limited internal fixation combined with an external fixator are 2 of the most commonly used methods of tibial plafond fracture repair. However, conclusions regarding the superior choice remain controversial. The present meta-analysis aimed to quantitatively compare the postoperative complications between open reduction and internal fixation and limited internal fixation combined with an external fixator for tibial plafond fractures. Nine studies with 498 fractures in 494 patients were included in the present study. The meta-analysis found no significant differences in bone healing complications (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.68 to 2.01, p = .58], nonunion (RR 1.09, 95% CI 0.51 to 2.36, p = .82), malunion or delayed union (RR 1.24, 95% CI 0.57 to 2.69, p = .59), superficial (RR 1.56, 95% CI 0.43 to 5.61, p = .50) and deep (RR 1.89, 95% CI 0.62 to 5.80) infections, arthritis symptoms (RR 1.20, 95% CI 0.92 to 1.58, p = .18), or chronic osteomyelitis (RR 0.31, 95% CI 0.05 to 1.84, p = .20) between the 2 groups. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Limb Lengthening and Then Insertion of an Intramedullary Nail: A Case-matched Comparison

PubMed Central

Kleinman, Dawn; Fragomen, Austin T.; Ilizarov, Svetlana

2008-01-01

Distraction osteogenesis is an effective method for lengthening, deformity correction, and treatment of nonunions and bone defects. The classic method uses an external fixator for both distraction and consolidation leading to lengthy times in frames and there is a risk of refracture after frame removal. We suggest a new technique: lengthening and then nailing (LATN) technique in which the frame is used for gradual distraction and then a reamed intramedullary nail inserted to support the bone during the consolidation phase, allowing early removal of the external fixator. We performed a retrospective case-matched comparison of patients lengthened with LATN (39 limbs in 27 patients) technique versus the classic (34 limbs in 27 patients). The LATN group wore the external fixator for less time than the classic group (12 versus 29 weeks). The LATN group had a lower external fixation index (0.5 versus 1.9) and a lower bone healing index (0.8 versus 1.9) than the classic group. LATN confers advantages over the classic method including shorter times needed in external fixation, quicker bone healing, and protection against refracture. There are also advantages over the lengthening over a nail and internal lengthening nail techniques. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18800209

Distal femoral osteotomy in genovalgum: internal fixation with blade plate versus casting.

PubMed

Makhmalbaf, Hadi; Moradi, Ali; Ganji, Saeid

2014-10-01

To compare the results of two different ways of distal femoral osteotomy stabilization in patients suffering from genuvalgum: internal fixation with plate, and casting. In a non-randomized prospective study, after distal femoral osteotomy with the zigzag method, patients were divided into two groups: long leg casting, and internal fixation with blade plate. For all patients, questionnaires were filled to obtain data. Information such as range of motion, tibiofemoral anatomical angle and complications were recorded. 38 knees with valgus deformity underwent distal femoral supracondylar osteotomy. (8 with plaster cast and 30 with internal fixation using a blade plate). Preoperative range of motion was 129±6° and six months later it was 120±14°. The preoperative tibiofemoral angle was 32±6°; postoperative tibiofemoral angles were 3±3°, 6±2°, and 7±3° just after operation, six months, and two years later, respectively. Although this angle was greater among the group stabilized with a cast, this difference was not statistically significant. In postoperative complications, over-correction was found in five, recorvatom deformity in one, knee stiffness in three and superficial wound infection was recorded in three knees. There is no prominent difference in final range of motion and alignment whether fixation is done with casting or internal fixation. However, the complication rate seems higher in the casting method.

External fixators in the treatment of midshaft clavicle non-unions: a systematic review.

PubMed

Barlow, Tim; Upadhyay, Piyush; Barlow, David

2014-02-01

Non- or mal-union of the clavicle is reported to occur in up to 15 % of conservatively treated fractures: the purpose of this systematic review is to examine the evidence for the use of external fixation in the treatment of clavicular non-union. We performed a search of MEDLINE and Embase, including all papers using external fixators for the treatment of clavicular non-union. Four papers satisfied our eligibility criteria: three case series and one case-control study. Level of evidence and quality assessment scoring were performed using published methods. Due to the heterogeneity of the study populations and interventions, no attempt at meta-analysis was made. External fixation in hypertrophic non-union of the clavicle, but not atrophic non-union, appears to be a reasonable treatment option. A pragmatic, multicentre, randomised controlled trial comparing external fixation and open reduction internal fixation in the treatment of hypertrophic non-union of the clavicle would be valuable.

Basin-wide N2 fixation in the deep waters of the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Benavides, Mar; Bonnet, Sophie; Hernández, Nauzet; Martínez-Pérez, Alba María.; Nieto-Cid, Mar; Álvarez-Salgado, Xosé Antón; Baños, Isabel; Montero, María. F.; Mazuecos, Ignacio P.; Gasol, Josep M.; Osterholz, Helena; Dittmar, Thorsten; Berman-Frank, Ilana; Arístegui, Javier

2016-06-01

Recent findings indicate that N2 fixation is significant in aphotic waters, presumably due to heterotrophic diazotrophs depending on organic matter for their nutrition. However, the relationship between organic matter and heterotrophic N2 fixation remains unknown. Here we explore N2 fixation in the deep chlorophyll maximum and underneath deep waters across the whole Mediterranean Sea and relate it to organic matter composition, characterized by optical and molecular methods. Our N2 fixation rates were in the range of those previously reported for the euphotic zone of the Mediterranean Sea (up to 0.43 nmol N L-1 d-1) and were significantly correlated to the presence of relatively labile organic matter with fluorescence and molecular formula properties representative for peptides and unsaturated aliphatics and associated with the presence of more oxygenated ventilated water masses. Finally, and despite that the aphotic N2 fixation contributes largely to total water column diazotrophic activity (>50%), its contribution to overall nitrogen inputs to the basin is negligible (<0.5%).

The Use of Mesh Plates for Difficult Fractures of the Patella.

PubMed

Volgas, David; Dreger, Tina K

2017-03-01

Patella fractures present some of the more complicated fracture patterns in orthopaedic trauma care. This is partially due to the small size of the fragments but also the articular nature of each fragment. Fixation methods such as cerclage wiring, excision of smaller fragments, and screw fixation of larger fragments all have their own challenges. Our study examined our Level I trauma center's experience with variable angle locked 2.7 mm titanium plates for treatment of comminuted patella fractures or treatment of patellar nonunion. After Institutional Review Board approval, we used billing records to identify 105 patients who had undergone operative management of a displaced patella fracture between January 2011 and December 2015. We reviewed the radiographs of these patients to identify which patients underwent treatment with a mesh plate. We found 16 patients (6 males and 10 females) who had undergone fixation with a mesh plate; mean age was 47 years. Nine patients underwent primary open reduction internal fixation (ORIF) and seven underwent mesh plate fixation for failed ORIF of a patella fracture. The mean visual analog pain score was 2.75 (range, 0-9). The mean range of motion was 1 degree of extension (range, 0-10 degrees) to 110 degrees of flexion (range, 45-135 degrees). All fractures healed. Five patients required hardware removal for pain. This review illustrates the effectiveness of the locking mesh plate in two challenging clinical scenarios: that of patellar nonunion and comminuted fractures that preclude standard fixation methods. Although multiple options exist for patellar fracture fixation, the titanium mesh locking plate can be an effective option for retaining the patella in the setting of comminution. Further comparative studies should be undertaken to determine which method of treatment may be superior in the treatment of these fractures. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

[Atlanto-axial pedicle screw fixation through posterior approach for treatment of atlanto-axial joint instability].

PubMed

Zuo, Chun-Guang; Liu, Xia-Jun; Wang, Xin-Hu; Wang, Jian-shun

2013-01-01

To discuss the therapeutic effects of the atlantoaxial pedicle screw system fixation in treatment of atlantoaxial instability. From June 2003 to March 2010, 32 patients with atlantoaxial instability were treated by atlantoaxial pedicle screw system fixation, included 21 males and 11 females wiht an average age of 42.5 years old ranging from 28 to 66 years. Among them, 18 cases were odontoid process fractures, 7 were congenital dissociate odontoid process, 4 were Jefferson fracture combined with odontoid fracture, 3 were rheumatic arthritis causing atlantoaxial instability. All patients suffered from the atlantoaxial subluxation and atlantoaxial instability. The JOA score ranged from 4 to 14 (means 9.1 +/- 0.3) before operation. The patients had some image examination including the X-ray of cervical vertebrae (include of dynamic position film), spiral CT 3D reconstruction and/or MRI. The position of pedicle screw system implantation,the angle of pedicle screw system implantation and screw length were measured. Operating skull traction. Operation undewent general anesthesia, implanted the pedicle screw, reduction and bone fusion under direct vision. The bone was fixated between posterior arch of atlas and lamina of axis by the lateral combination bended to posterior. One hundred and twenty-eight atlantoaxial pedicle screws were implanted in 32 patients. No patient had the injure of spinal cord, nerve root and vertebral artery. All patients were followed-up from 6 to 48 months (averaged 16 months). After operation, the JOA score ranged from 11 to 17 (averaged 15.9 +/- 0.2), improvement rate was 86.1%. The fracture of odontoid process were healing completely. All fusion bone were combinated. The internal fixation wasn't loosening and breaking. The atlantoaxial pedicle screw system fixation was effective method to treat atlantoaxial instability. The method had many advantages, such as provide rigid and short segment fixation, safe and simple, high fusion rate. The method was worth in clinical application.

The effect of cement on hip stem fixation: a biomechanical study.

PubMed

Çelik, Talip; Mutlu, İbrahim; Özkan, Arif; Kişioğlu, Yasin

2017-06-01

This study presents the numerical analysis of stem fixation in hip surgery using with/without cement methods since the use of cement is still controversial based on the clinical studies in the literature. Many different factors such as stress shielding, aseptic loosening, material properties of the stem, surgeon experiences etc. play an important role in the failure of the stem fixations. The stem fixation methods, cemented and uncemented, were evaluated in terms of mechanical failure aspects using computerized finite element method. For the modeling processes, three dimensional (3D) femur model was generated from computerized tomography (CT) images taken from a patient using the MIMICS Software. The design of the stem was also generated as 3D CAD model using the design parameters taken from the manufacturer catalogue. These 3D CAD models were generated and combined with/without cement considering the surgical procedure using SolidWorks program and then imported into ANSYS Workbench Software. Two different material properties, CoCrMo and Ti6Al4V, for the stem model and Poly Methyl Methacrylate (PMMA) for the cement were assigned. The material properties of the femur were described according to a density calculated from the CT images. Body weight and muscle forces were applied on the femur and the distal femur was fixed for the boundary conditions. The calculations of the stress distributions of the models including cement and relative movements of the contacts examined to evaluate the effects of the cement and different stem material usage on the failure of stem fixation. According to the results, the use of cement for the stem fixation reduces the stress shielding but increases the aseptic loosening depending on the cement crack formations. Additionally, using the stiffer material for the stem reduces the cement stress but increases the stress shielding. Based on the results obtained in the study, even when taking the disadvantages into account, the cement usage is more suitable for the hip fixations.

External fixation techniques for distal radius fractures.

PubMed

Capo, John T; Swan, Kenneth G; Tan, Virak

2006-04-01

Fractures of the distal radius are common injuries. Low-energy or high-energy mechanisms may be involved. Unstable distal radius fractures present a challenge to the treating orthopaedic surgeon. External fixation is a valuable instrument for fracture reduction and stabilization. Limited open incisions, early range of motion, and treatment of complex wounds are a few of the benefits of external fixation. Fixators may be spanning or nonbridging and may be used alone or in combination with other stabilization methods to obtain and maintain distal radius fracture reduction. Augmentation with percutaneous wires allows for optimal fracture stabilization with physiologic alignment of the wrist. Moderate distraction at the carpus does not induce postoperative stiffness. The distal radioulnar joint must be assessed and may need to be stabilized. Complications of external fixation are usually minor, but must be anticipated and treated early. Level V (expert opinion).

Comparison of two preparatory techniques for urine cytology.

PubMed Central

Dhundee, J; Rigby, H S

1990-01-01

Two methods of preparation of urine for cytology were compared retrospectively. In method 1 cells in the urine were fixed after the preparation of the smear; in method 2 the cells were fixed before smear preparation. Urine cytology reports were correlated with subsequent histological analysis. The specificities of urine cytology using both methods were high (99%). The sensitivity using method 1 was 87%; using method 2 it was 65%. This difference was significant. The cell preparation technique therefore significantly changes the sensitivity of urine cytology. Cellular fixation after smear preparation is preferable to smear preparation after fixation. PMID:2266176

A novel combined method of osteosynthesis in treatment of tibial fractures: a comparative study on sheep with application of rod-through-plate fixator and bone plating.

PubMed

Tralman, G; Andrianov, V; Arend, A; Männik, P; Kibur, R T; Nõupuu, K; Uksov, D; Aunapuu, M

2013-04-01

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod-through-plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep. © 2012 Blackwell Verlag GmbH.

[Case-control study on effects of external fixation combined with limited internal fixation for the treatment of Pilon fractures of Rüedi-Allgower type III].

PubMed

Duan, Da-Peng; You, Wu-Lin; Ji, Le; Zhang, Yong-Tao; Dang, Xiao-Qian; Wang, Kun-Zheng

2014-01-01

To analyze the effects of three surgical operations in the treatment of Pilon fracture of Rüedi-Allgower type III, and put forward the best therapeutic method. The clinical data of 33 patients with Pilon fracture who received surgical operations (plaster immobilization group, 10 cases; distal tibia anatomical plate group, 11 cases; external fixation with limited internal fixation group, 12 cases) from October 2009 to January 2012 were analyzed. There were 5 males and 5 females, ranging in age from 24 to 61 years in the plaster immobilization group. There were 7 males and 4 females, ranging in age from 21 to 64 years in the distal tibia anatomical plate group. There were 7 males and 5 females, ranging in age from 23 to 67 years in the external fixation with limited internal fixation group. The Ankle X-ray of Pilon fracture after operation, ankle score, early and late complications were collected. Bourne system was used to evaluate ankle joint function. After 8 months to 3 years follow-up, it was found that three kinds of treatment had significant differences in the outcomes and complications (P < 0.05): the external fixation with limited internal fixation group got the best results. The number of anatomic reduction cases in the external fixation with limited internal fixation group (7 cases) and the distal tibia anatomical plate group (8 cases) was more than the plaster immobilization group (2 cases). According to the ankle score, 8 patients got an excellent result, 3 good and 1 poor in the limited internal fixation group ,which was better than those of distal tibia anatomical plate group (5 excellent, 4 good and 2 poor) and the plaster immobilization group (3 excellent, 4 good and 3 poor). The number of early and late complications in the external fixation with limited internal fixation group was more than those in the plaster immobilization group and the distal tibia anatomical plate group (P< 0.05). Treatment of external fixation with limited internal fixation in the treatment of Pilon fracture of Rüedi-Allgower type III is effective and safe.

Modification of the Microtiter Reading Mirror for Use in the Standardized Micro Complement Fixation Test

PubMed Central

Hui, Gabriel W. K.

1971-01-01

Modification of the Microtiter reading mirror used in the standardized diagnostic complement fixation method permits convenient estimation of the results in per cent hemolysis by direct visual comparison with the hemolytic standards. Images PMID:5564678

[Domestic external fixator application in the treatment of limb deformities: 7 289 cases application report].

PubMed

Qin, S H; Guo, B F; Zheng, X J; Jiao, S F; Xia, H T; Peng, A M; Pan, Q; Zang, J C; Wang, Z J

2017-09-01

Objective: To discuss the clinical application and effects of domestic external fixator in the treatment of patients with malformations of limbs. Methods: A total of 7 289 patients with malformation of limbs who had been operated in Qin Sihe orthopedic surgery team from January 1989 to June 2016 were retrospective analyzed. The patients were treated with domestic external fixator, including 4 033 males and 3 256 females, aging from 2 to 82 years with a mean age of 23.4 years. There were 2 732 patients using Ilizarov external fixator, 4 713 patients using hybrid external fixator, 57 patients using monobrachial external fixator, 232 patients using Ilizarov external fixator and hybrid external fixator. The Ilizarov, hybrid and monobrachial external fixator were used in 67, 65 and 0 patients on the upper limbs and in 2 665, 4 616 and 57 patients on the lower limbs. There were 3 028 patients operated on the left limbs, 3 260 patients operated on the right limbs and 1 001 patients operated on the bilateral limbs. The top three types of diseases were sequelae of poliomyelitis, cerebral palsy and post-traumatic stress disorder peromely. Deformity types inclued talipes equinovarus, knee flexion deformity, cavus foot and so on. Results: All the patients were followed up for a period of 2.5 months to 22.4 years, with an average follow-up time of 5.4 years. All of the external fixators were used for single once, and there was no substitute for external fixator quality problem. All the patients were completed surgery goal until removing external fixation except 1 patient gave up treatment and 1 removed the fixator because of metal allergy. The common complications included wire or pin infection and joint movement limitation and so on. Conclusions: The domestic external fixator developed and produced based on the characteristics of Chinese limb deformity disability. The domestic external fixator can be used to treat kinds of limb deformities with the advantages of practical, economical, adjustable, universal and portable. The domestic external fixator could meet the clinical demand for fixation of the osteotomy end of the limbs, the correction of the deformity, the repair of the defects and the limb lengthening.

[Surgical strategy for upper cervical vertebrae instability through the anterior approach].

PubMed

Huang, Wei-bing; Cai, Xian-hua; Chen, Zhuang-hong; Huang, Ji-feng; Liu, Xi-ming; Wei, Shi-jun

2013-07-01

To explore the choice and effect of internal fixation in treating upper cervical vertebrae instability through anterior approach. From March 2000 to September 2010,83 patients with upper cervical vertebrae instability were treated with internal fixation through anterior approach. There were 59 males and 24 females with a mean age of 42 years old (ranged, 20 to 68). Among these patients, 36 patients were treated with odontoid screw fixation, 16 patients with C1,2 transarticular screw fixation, 23 patients with C2,3 steel plate fixation, 5 patients with odontoid screw and transarticular screw fixation,2 patients with odontoid screw and C2.3 steel plate fixation, 1 patient with C1,2 transarticular screw and C2,3 steel plate fixation. One patient with completely cervical vertebrae cord injury died of pulmonary infection after C1,2 transarticular screw fixation. Other patients were followed up from 8 to 36 months with an average of 15 months. Upper cervical vertebrae stability were restored without vertebral artery and spinal cord injury. Thirty-six patients were treated with odontoid screw fixation and 5 patients were treated with screw combined with transarticular screw fixation obtained bone union in the dentations without bone graft. Among the 16 patients treated with C1,2 transarticular screw fixation, 13 patients obtained bone union after bone graft; 1 patient died of pulmonary infection after surgery; 1 patient with comminuted odontoid fracture of type II C and atlantoaxial anterior dislocation did not obtain bone union after bone graft,but the fibrous healing was strong enough to maintain the atlantoaixal joint stability; 1 patient with obsolete atlantoaxial anterior dislocation were re-treated with Brooks stainless steel wire fixation and bone graft through posterior approach, and finally obtained bone union. It could obtain satisfactory effects depending on the difference of cervical vertebrae instability to choose the correctly surgical method.

Conventional plate fixation method versus pre-operative virtual simulation and three-dimensional printing-assisted contoured plate fixation method in the treatment of anterior pelvic ring fracture.

PubMed

Hung, Chun-Chi; Li, Yuan-Ta; Chou, Yu-Ching; Chen, Jia-En; Wu, Chia-Chun; Shen, Hsain-Chung; Yeh, Tsu-Te

2018-05-03

Treating pelvic fractures remains a challenging task for orthopaedic surgeons. We aimed to evaluate the feasibility, accuracy, and effectiveness of three-dimensional (3D) printing technology and computer-assisted virtual surgery for pre-operative planning in anterior ring fractures of the pelvis. We hypothesized that using 3D printing models would reduce operation time and significantly improve the surgical outcomes of pelvic fracture repair. We retrospectively reviewed the records of 30 patients with pelvic fractures treated by anterior pelvic fixation with locking plates (14 patients, conventional locking plate fixation; 16 patients, pre-operative virtual simulation with 3D, printing-assisted, pre-contoured, locking plate fixation). We compared operative time, instrumentation time, blood loss, and post-surgical residual displacements, as evaluated on X-ray films, among groups. Statistical analyses evaluated significant differences between the groups for each of these variables. The patients treated with the virtual simulation and 3D printing-assisted technique had significantly shorter internal fixation times, shorter surgery duration, and less blood loss (- 57 minutes, - 70 minutes, and - 274 ml, respectively; P < 0.05) than patients in the conventional surgery group. However, the post-operative radiological result was similar between groups (P > 0.05). The complication rate was less in the 3D printing group (1/16 patients) than in the conventional surgery group (3/14 patients). The 3D simulation and printing technique is an effective and reliable method for treating anterior pelvic ring fractures. With precise pre-operative planning and accurate execution of the procedures, this time-saving approach can provide a more personalized treatment plan, allowing for a safer orthopaedic surgery.

Preclinical evaluation of the effect of the combined use of the Ethicon Securestrap® Open Absorbable Strap Fixation Device and Ethicon Physiomesh™ Open Flexible Composite Mesh Device on surgeon stress during ventral hernia repair

PubMed Central

Sutton, Nadia; MacDonald, Melinda H; Lombard, John; Ilie, Bodgan; Hinoul, Piet; Granger, Douglas A

2018-01-01

Aim To evaluate whether performing ventral hernia repairs using the Ethicon Physiomesh™ Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap® Open Absorbable Strap Fixation Device reduces surgical time and surgeon stress levels, compared with traditional surgical repair methods. Methods To repair a simulated ventral incisional hernia, two surgeries were performed by eight experienced surgeons using a live porcine model. One procedure involved traditional suture methods and a flat mesh, and the other procedure involved a mechanical fixation device and a skirted flexible composite mesh. A Surgery Task Load Index questionnaire was administered before and after the procedure to establish the surgeons’ perceived stress levels, and saliva samples were collected before, during, and after the surgical procedures to assess the biologically expressed stress (cortisol and salivary alpha amylase) levels. Results For mechanical fixation using the Ethicon Physiomesh Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap Open Absorbable Strap Fixation Device, surgeons reported a 46.2% reduction in perceived workload stress. There was also a lower physiological reactivity to the intraoperative experience and the total surgical procedure time was reduced by 60.3%. Conclusions This study provides preliminary findings suggesting that the combined use of a mechanical fixation device and a skirted flexible composite mesh in an open intraperitoneal onlay mesh repair has the potential to reduce surgeon stress. Additional studies are needed to determine whether a reduction in stress is observed in a clinical setting and, if so, confirm that this results in improved clinical outcomes. PMID:29296101

Rates of Dinitrogen Fixation and the Abundance of Diazotrophs in North American Coastal Waters Between Cape Hatteras and Georges Bank

NASA Technical Reports Server (NTRS)

Mulholland, M.R.; Bernhardt, P. W.; Blanco-Garcia, J. L.; Mannino, A.; Hyde, K.; Mondragon, E.; Turk, K.; Moisander, P. H.; Zehr, J. P.

2012-01-01

We coupled dinitrogen (N2) fixation rate estimates with molecular biological methods to determine the activity and abundance of diazotrophs in coastal waters along the temperate North American Mid-Atlantic continental shelf during multiple seasons and cruises. Volumetric rates of N2 fixation were as high as 49.8 nmol N L(sup -1) d(sup -1) and areal rates as high as 837.9 micromol N m(sup -2) d(sup -1) in our study area. Our results suggest that N2 fixation occurs at high rates in coastal shelf waters that were previously thought to be unimportant sites of N2 fixation and so were excluded from calculations of pelagic marine N2 fixation. Unicellular N2-fixing group A cyanobacteria were the most abundant diazotrophs in the Atlantic coastal waters and their abundance was comparable to, or higher than, that measured in oceanic regimes where they were discovered. High rates of N2 fixation and the high abundance of diazotrophs along the North American Mid-Atlantic continental shelf highlight the need to revise marine N budgets to include coastal N2 fixation. Integrating areal rates of N2 fixation over the continental shelf area between Cape Hatteras and Nova Scotia, the estimated N2 fixation in this temperate shelf system is about 0.02 Tmol N yr(sup -1), the amount previously calculated for the entire North Atlantic continental shelf. Additional studies should provide spatially, temporally, and seasonally resolved rate estimates from coastal systems to better constrain N inputs via N2 fixation from the neritic zone.

Maxillomandibular Fixation by Plastic Surgeons: Cost Analysis and Utilization of Resources.

PubMed

Farber, Scott J; Snyder-Warwick, Alison K; Skolnick, Gary B; Woo, Albert S; Patel, Kamlesh B

2016-09-01

Maxillomandibular fixation (MMF) can be performed using various techniques. Two common approaches used are arch bars and bone screws. Arch bars are the gold standard and inexpensive, but often require increased procedure time. Bone screws with wire fixation is a popular alternative, but more expensive than arch bars. The differences in costs of care, complications, and operative times between these 2 techniques are analyzed. A chart review was conducted on patients treated over the last 12 years at our institution. Forty-four patients with CPT code 21453 (closed reduction of mandible fracture with interdental fixation) with an isolated mandible fracture were used in our data collection. The operating room (OR) costs, procedure duration, and complications for these patients were analyzed. Operative times were significantly shorter for patients treated with bone screws (P < 0.002). The costs for one trip to the OR for either method of fixation did not show any significant differences (P < 0.840). More patients with arch bar fixation (62%) required a second trip to the OR for removal in comparison to those with screw fixation (31%) (P < 0.068). This additional trip to the OR added significant cost. There were no differences in patient complications between these 2 fixation techniques. The MMF with bone screws represents an attractive alternative to fixation with arch bars in appropriate scenarios. Screw fixation offers reduced costs, fewer trips to the OR, and decreased operative duration without a difference in complications. Cost savings were noted most significantly in a decreased need for secondary procedures in patients who were treated with MMF screws. Screw fixation offers potential for reducing the costs of care in treating patients with minimally displaced or favorable mandible fractures.

A Novel Vesicoscopic Bladder Wall Suture Fixation Technique to Aid Endoscopic Vesicostomy Button Insertion

PubMed Central

Adam, Ahmed; Sookram, Jayveer

2018-01-01

Background To describe a novel bladder fixation technique for use during endoscopic vesicostomy button insertion. Methods After standard cystoscopic visualization of the bladder, a standard 18 G intravenous cannula was inserted into the bladder. A non-absorbable suture thread was placed through this intravenous cannula under cystoscopic vision. The proximal end of the suture was then removed using standard ureteroscopic grasping forceps (3 Fr) through another needle (15 G) inserted next to the initial puncture site (following a path at 30 degrees from the initial puncture tract) into the bladder. The suture ends were brought out of the bladder and tied at the skin level, 2 cm from the intended vesicostomy site. Sutures were removed on the second postoperative day. Results This fixation technique allows for adequate fixation of the bladder dome to the anterior abdominal wall. These sutures also have less potential for cutaneous scarring and pain. No complications were reported. Conclusion This simple fixation technique is easily performed using materials found in every urology suite. It also avoids the skills required with other previously reported fixation suture techniques, and can also be utilized for bladder fixation in cases of vesicoscopic laparoscopic or robotic assisted laparoscopic procedures. PMID:29692696

Arthrodesis for failed knee arthroplasty. A report of 20 cases.

PubMed

Knutson, K; Lindstrand, A; Lidgren, L

1985-01-01

Twenty consecutive patients treated by arthrodesis for failed knee arthroplasty are reviewed. Eight hinged, five stabilised and seven compartmental prostheses were removed, for infection (15 cases), loosening (4) and instability (1). One patient refused a second-stage operation but the remainder gained sound fusion. Infected knees had a two-stage procedure with temporary insertion of gentamicin-loaded beads after removal of the prosthesis; all infections healed. Six arthrodeses using a Hoffmann-Vidal external fixator resulted in two temporary failures. One Ace-Fischer external fixation was successful. Of 10 primary attempts at arthrodesis with an intramedullary Küntscher nail, nine were successful; the tenth fused after two more attempts by the same method. The two failures of external fixation and two failures after Charnley single-frame compression done elsewhere were successfully fused with intramedullary nails. Delayed union in three cases fused after prolonged fixation and repeated bone grafts. The indications for and methods of arthrodesis after failed knee arthroplasty are discussed.

Method of fabricating metal- and ceramic- matrix composites and functionalized textiles

DOEpatents

Maxwell, James L [Jemez Springs, NM; Chavez, Craig A [Los Alamos, NM; Black, Marcie R [Lincoln, MA

2012-04-17

A method of manufacturing an article comprises providing a first sheet, wetting the first sheet with a liquid precursor to provide a first wet sheet, and irradiating the first wet sheet in a pattern corresponding to a first cross section of the article such that the liquid precursor is at least partially converted to a solid in the first cross section. A second sheet is disposed adjacent to the first sheet. The method further comprises wetting the second sheet with the liquid precursor to provide a second wet sheet, and irradiating the second wet sheet in a pattern corresponding to a second cross section of the article such that the liquid precursor is at least partially converted to a solid in the second cross section. In particular the liquid precursor may be converted to a metal, ceramic, semiconductor, semimetal, or a combination of these materials.

Variable selection based near infrared spectroscopy quantitative and qualitative analysis on wheat wet gluten

NASA Astrophysics Data System (ADS)

Lü, Chengxu; Jiang, Xunpeng; Zhou, Xingfan; Zhang, Yinqiao; Zhang, Naiqian; Wei, Chongfeng; Mao, Wenhua

2017-10-01

Wet gluten is a useful quality indicator for wheat, and short wave near infrared spectroscopy (NIRS) is a high performance technique with the advantage of economic rapid and nondestructive test. To study the feasibility of short wave NIRS analyzing wet gluten directly from wheat seed, 54 representative wheat seed samples were collected and scanned by spectrometer. 8 spectral pretreatment method and genetic algorithm (GA) variable selection method were used to optimize analysis. Both quantitative and qualitative model of wet gluten were built by partial least squares regression and discriminate analysis. For quantitative analysis, normalization is the optimized pretreatment method, 17 wet gluten sensitive variables are selected by GA, and GA model performs a better result than that of all variable model, with R2V=0.88, and RMSEV=1.47. For qualitative analysis, automatic weighted least squares baseline is the optimized pretreatment method, all variable models perform better results than those of GA models. The correct classification rates of 3 class of <24%, 24-30%, >30% wet gluten content are 95.45, 84.52, and 90.00%, respectively. The short wave NIRS technique shows potential for both quantitative and qualitative analysis of wet gluten for wheat seed.

Management of Sacral Tumors Requiring Spino-Pelvic Reconstruction with Different Histopathologic Diagnosis: Evaluation with Four Cases

PubMed Central

Togral, Guray; Hasturk, Askin Esen; Kekec, Fevzi; Parpucu, Murat; Gungor, Safak

2015-01-01

In this retrospective study, surgical results of four patients with sacral tumors having disparate pathologic diagnoses, who were treated with partial or total sacrectomy and lumbopelvic stabilization were abstracted. Two patients were treated with partial sacral resection and two patients were treated with total sacrectomy and spinopelvic fixation. Fixation methods included spinopelvic fixation with rods and screws in two cases, reconstruction plate in one case, and fresh frozen allografts in two cases. Fibular allografts used for reconstruction accelerated bony union and enhanced the stability in two cases. Addition of polymethyl methacrylate in the cavity in the case of a giant cell tumor had a positive stabilizing effect on fixation. As a result, we can conclude that mechanical instability after sacral resection can be stabilized securely with lumbopelvic fixation and polymethyl methacrylate application or addition of fresh frozen allografts between the rods can augment the stability of the reconstruction. PMID:26713133

Management of Sacral Tumors Requiring Spino-Pelvic Reconstruction with Different Histopathologic Diagnosis: Evaluation with Four Cases.

PubMed

Arıkan, Murat; Togral, Guray; Hasturk, Askin Esen; Kekec, Fevzi; Parpucu, Murat; Gungor, Safak

2015-12-01

In this retrospective study, surgical results of four patients with sacral tumors having disparate pathologic diagnoses, who were treated with partial or total sacrectomy and lumbopelvic stabilization were abstracted. Two patients were treated with partial sacral resection and two patients were treated with total sacrectomy and spinopelvic fixation. Fixation methods included spinopelvic fixation with rods and screws in two cases, reconstruction plate in one case, and fresh frozen allografts in two cases. Fibular allografts used for reconstruction accelerated bony union and enhanced the stability in two cases. Addition of polymethyl methacrylate in the cavity in the case of a giant cell tumor had a positive stabilizing effect on fixation. As a result, we can conclude that mechanical instability after sacral resection can be stabilized securely with lumbopelvic fixation and polymethyl methacrylate application or addition of fresh frozen allografts between the rods can augment the stability of the reconstruction.

Improved harvesting systems for wet sites

Treesearch

Bryce J. Stokes; Alvin Schilling

1997-01-01

Environmentally acceptable and economical forest operations are needed for sustainable management of forest resources. Improved methods for harvesting and transporting timber are especially needed for wet sites. As the demand for hardwood lumber continues to increase, improved and alternative methods are needed to ensure acceptance of timber harvesting for the wet site...

Finite element analysis of the three different posterior malleolus fixation strategies in relation to different fracture sizes.

PubMed

Anwar, Adeel; Lv, Decheng; Zhao, Zhi; Zhang, Zhen; Lu, Ming; Nazir, Muhammad Umar; Qasim, Wasim

2017-04-01

Appropriate fixation method for the posterior malleolar fractures (PMF) according to the fracture size is still not clear. Aim of this study was to evaluate the outcomes of the different fixation methods used for fixation of PMF by finite element analysis (FEA) and to compare the effect of fixation constructs on the size of the fracture computationally. Three dimensional model of the tibia was reconstructed from computed tomography (CT) images. PMF of 30%, 40% and 50% fragment sizes were simulated through computational processing. Two antero-posterior (AP) lag screws, two postero-anterior (PA) lag screws and posterior buttress plate were analysed for three different fracture volumes. The simulated loads of 350N and 700N were applied to the proximal tibial end. Models were fixed distally in all degrees of freedom. In single limb standing condition, the posterior plate group produced the lowest relative displacement (RD) among all the groups (0.01, 0.03 and 0.06mm). Further nodal analysis of the highest RD fracture group showed a higher mean displacement of 4.77mm and 4.23mm in AP and PA lag screws model (p=0.000). The amounts of stress subjected to these implants, 134.36MPa and 140.75MPa were also significantly lower (p=0.000). There was a negative correlation (p=0.021) between implant stress and the displacement which signifies a less stable fixation using AP and PA lag screws. Progressively increasing fracture size demands more stable fixation construct because RD increases significantly. Posterior buttress plate produces superior stability and lowest RD in PMF models irrespective of the fragment size. Copyright © 2017 Elsevier Ltd. All rights reserved.

A different and safe method of split thickness skin graft fixation: medical honey application.

PubMed

Emsen, Ilteris Murat

2007-09-01

Honey has been used for medicinal purposes since ancient times. Its antibacterial effects have been established during the past few decades. Still, modern medical practitioners hesitate to apply honey for local treatment of wounds. This may be because of the expected messiness of such local application. Hence, if honey is to be used for medicinal purposes, it has to meet certain criteria. The authors evaluated its use for the split thickness skin graft fixation because of its adhesive and other beneficial effects in 11 patients. No complications such as graft loss, infection, and graft rejection were seen. Based on these results, the authors advised honey as a new agent for split thickness skin graft fixation. In recent years there has been a renewed interest in honey wound management. There are a range of regulated wound care products that contain honey available on the Drug Tariff. This article addresses key issues associated with the use of honey, outlining how it may be best used, in which methods of split thickness skin graft fixations it may be used, and what clinical outcomes may be anticipated. For this reason, 11 patients who underwent different diagnosis were included in this study. In all the patients same medical honey was used for the fixation of the skin graft. No graft loss was seen during both the first dressing and the last view of the grafted areas. As a result, it has been shown that honey is also a very effective agent for split thickness skin graft fixations. Because it is a natural agent, it can be easily used in all skin graft operation for the fixation of the split thickness skin grafts.

Accurate and Simple Screw Insertion Procedure With Patient-Specific Screw Guide Templates for Posterior C1-C2 Fixation.

PubMed

Sugawara, Taku; Higashiyama, Naoki; Kaneyama, Shuichi; Sumi, Masatoshi

2017-03-15

Prospective clinical trial of the screw insertion method for posterior C1-C2 fixation utilizing the patient-specific screw guide template technique. To evaluate the efficacy of this method for insertion of C1 lateral mass screws (LMS), C2 pedicle screws (PS), and C2 laminar screws (LS). Posterior C1LMS and C2PS fixation, also known as the Goel-Harms method, can achieve immediate rigid fixation and high fusion rate, but the screw insertion carries the risk of injury to neuronal and vascular structures. Dissection of venous plexus and C2 nerve root to confirm the insertion point of the C1LMS may also cause problems. We have developed an intraoperative screw guiding method using patient-specific laminar templates. Preoperative bone images of computed tomography (CT) were analyzed using three-dimensional (3D)/multiplanar imaging software to plan the trajectories of the screws. Plastic templates with screw guiding structures were created for each lamina using 3D design and printing technology. Three types of templates were made for precise multistep guidance, and all templates were specially designed to fit and lock on the lamina during the procedure. Surgery was performed using this patient-specific screw guide template system, and placement of the screws was postoperatively evaluated using CT. Twelve patients with C1-C2 instability were treated with a total of 48 screws (24 C1LMS, 20 C2PS, 4 C2LS). Intraoperatively, each template was found to exactly fit and lock on the lamina and screw insertion was completed successfully without dissection of the venous plexus and C2 nerve root. Postoperative CT showed no cortical violation by the screws, and mean deviation of the screws from the planned trajectories was 0.70 ± 0.42 mm. The multistep, patient-specific screw guide template system is useful for intraoperative screw navigation in posterior C1-C2 fixation. This simple and economical method can improve the accuracy of screw insertion, and reduce operation time and radiation exposure of posterior C1-C2 fixation surgery. 3.

Fixation and mounting of porcine aortic valves for use in mock circuits.

PubMed

Schlöglhofer, Thomas; Aigner, Philipp; Stoiber, Martin; Schima, Heinrich

2013-10-01

Investigations of the circulatory system in vitro use mock circuits that require valves to mimic the cardiac situation. Whereas mechanical valves increase water hammer effects due to inherent stiffness and do not allow the use of pressure lines or catheters, bioprosthetic valves are expensive and of limited durability in test fluids. Therefore, we developed a cheap, fast, alternative method to mount valves obtained from the slaughterhouse in mock circuits. Porcine aortic roots were obtained from the abattoir and used either in native condition or after fixation. Fixation was performed at a constant retrograde pressure to ensure closed valve position. Fixation time was 4 h in a 0.5%-glutaraldehyde phosphate buffer. The fixed valves were molded into a modular mock circulation connector using a fast curing silicone. Valve functionality was evaluated in a pulsatile setting (cardiac output = 4.7 l/min, heart rate = 80 beats/min) and compared before and after fixation. Leaflet motion was recorded with a high-speed camera and valve insufficiency was quantified by leakage flow under steady pressure application (80 mmHg). Under physiological conditions the aortic valves showed almost equal leaflet motion in native and fixed conditions. However, the leaflets of the native valves showed lower stiffness and more fluttering during systole than the fixed specimens. Under retrograde pressure, fresh and fixed valves showed small leakage flows of <30 ml/min. The new mounting and fixation procedure is a fast method to fabricate low cost biologic valves for the use in mock circuits.

Does the thinking aloud condition affect the search for pulmonary nodules?

NASA Astrophysics Data System (ADS)

Littlefair, Stephen; Brennan, Patrick; Reed, Warren; Williams, Mark; Pietrzyk, Mariusz W.

2012-02-01

Aim: To measure the effect of thinking aloud on perceptual accuracy and visual search behavior during chest radiograph interpretation for pulmonary nodules. Background: Thinking Aloud (TA) is an empirical research method used by researchers in cognitive psychology and behavioural analysis. In this pilot study we wanted to examine whether TA had an effect on the perceptual accuracy and search patterns of subjects looking for pulmonary nodules on adult posterioranterior chest radiographs (PA CxR). Method: Seven academics within Medical Radiation Sciences at The University of Sydney participated in two reading sessions with and without TA. Their task was to localize pulmonary nodules on 30 PA CxR using mouse clicks and rank their confidence levels of nodule presence. Eye-tracking recordings were collected during both viewing sessions. Time to first fixation, duration of first fixation, number of fixations, cumulative time of fixation and total viewing time were analysed. In addition, ROC analysis was conducted on collected outcome using DBM methodology. Results: Time to first nodule fixation was significantly longer (p=0.001) and duration of first fixation was significantly shorter (p=0.043). No significant difference was observed in ROC AUC scores between control and TA conditions. Conclusion: Our results confirm that TA has little effect on perceptual ability or performance, except for prolonging the task. However, there were significant differences in visual search behavior. Future researchers in radio-diagnosis could use the think aloud condition rather than silence so as to more closely replicate the clinical scenario.

[Long-term efficacy of open reduction and internal fixation versus external fixation for unstable distal radius fractures: a meta-analysis].

PubMed

Yang, Z; Yuan, Z Z; Ma, J X; Ma, X L

2017-11-07

Objective: To make a systematic assessment of the Long-term efficacy of open reduction and internal fixation versus external fixation for unstable distal radius fractures. Methods: A computer-based online search of PubMed, ScienceDirect, EMBASE, BIOSIS, Springer and Cochrane Library were performed. The randomized and controlled trials of open reduction and internal fixation versus external fixation for unstable distal radius fractures were collected. The included trials were screened out strictly based on the criterion of inclusion and exclusion. The quality of included trials was evaluated. RevMan 5.0 was used for data analysis. Results: Sixteen studies involving 1 268 patients were included. There were 618 patients with open reduction and internal fixation and 650 with external fixation. The results of meta-analysis indicated that there were statistically significant differences with regard to the complications postoperatively (infection( I (2)=0%, RR =0.27, 95% CI 0.16-0.45, Z =4.92, P <0.000 01) and total complications( I (2)=0%, RR =0.71, 95% CI 0.59-0.85, Z =3.65, P =0.000 3) ), DASH scores( I (2)=37%, MD =-5.67, 95% CI -8.31--3.04, Z =4.22, P <0.000 1) and volar tilt( I (2)=78%, MD =2.29, 95% CI 0.33-4.24, Z =2.30, P =0.02)( P <0.05) at the end of follow-up period were noted. There were no statistically significant differences observed between two approaches with respect to the clinical outcomes (grip strength, flexion, extension, pronation, supination, radial deviation and ulnar deviation) and radiographic outcome(radial length) at the end of follow-up period( P <0.05). Conclusion: Both open reduction and internal fixation and external fixation are effective treatment for unstable distal radius fractures. Compared with external fixation, open reduction and internal fixation provides reduced complications postoperatively, lower DASH scores and better restoration of volar tilt for treatment of distal radius fractures.

Mechanical evaluation of external skeletal fixator-intramedullary pin tie-in configurations applied to cadaveral humeri from red-tailed hawks (Buteo jamaicensis).

PubMed

Van Wettere, Arnaud J; Redig, Patrick T; Wallace, Larry J; Bourgeault, Craig A; Bechtold, Joan E

2009-12-01

Use of external skeletal fixator-intramedullary pin (ESF-IM) tie-in fixators is an adjustable and effective method of fracture fixation in birds. The objective of this study was to determine the contribution of each of the following parameters to the compressive and torsional rigidity of an ESF-IM pin tie-in applied to avian bones with an osteotomy gap: (1) varying the fixation pin position in the proximal bone segment and (2) increasing the number of fixation pins in one or both bone segments. ESF-IM pin tie-in constructs were applied to humeri harvested from red-tailed hawks (Buteo jamaicensis) (n=24) that had been euthanatized for clinical reasons. Constructs with a variation in the placement of the proximal fixation pin and with 2, 3, or 4 fixation pins applied to avian bone with an osteotomy gap were loaded to a defined displacement in torque and axial compression. Response variables were determined from resulting load-displacement curves (construct stiffness, load at 1-mm displacement). Increasing the number of fixation pins from 1 to 2 per bone segment significantly increased the stiffness in torque (110%) and compression (60%), and the safe load in torque (107%) and compression (50%). Adding a fixation pin to the distal bone segment to form a 3-pin fixator significantly increased the stiffness (27%) and safe load (20%) in torque but not in axial compression. In the configuration with 2 fixation pins, placing the proximal pin distally in the proximal bone segment significantly increased the stiffness in torque (28%), and the safe load in torque (23%) and in axial compression (32%). Results quantified the relative importance of specific parameters affecting the rigidity of ESF-IM pin tie-in constructs as applied to unstable bone fracture models in birds.

Computational Evaluation of the Effects of Bone Ingrowth on Bone Resorptive Remodeling after a Cementless Total Hip Arthroplasty

NASA Astrophysics Data System (ADS)

Jung, Duk-Young; Kang, Yu-Bong; Tsutsumi, Sadami; Nakai, Ryusuke; Ikeuchi, Ken; Sekel, Ron

In this study, we simulated a wide cortex separation from a cementless hip prosthesis using the bone resorption remodeling method that is based on the generation of high compressive stress around the distal cortical bone. Thereafter, we estimated the effect on late migration quantities of the hip prosthesis produced by the interface state arising from bone ingrowth. This was accomplished using cortical bone remodeling over a long period of time. Two-dimensional natural hip and implanted hip FEM models were constructed with each of the following interface statements between the bone and prosthesis: (1) non-fixation, (2) proximal 1/3, (3) proximal 2/3 and (4) full-fixation. The fixation interfaces in the fully and partially porous coated regions were rigidly fixed by bony ingrowth. The non-fixation model was constructed as a critical situation, with the fibrous or bony tissue not integrated at all into the implant surface. The daily load history was generated using the three loading cases of a one-legged stance as well as abduction and adduction motions. With the natural hip and one-legged stance, the peak compressive principal stresses were found to be under the criteria value for causing bone resorption, while no implant movement occurred. The migration magnitude of the stem of the proximal 1/3 fixation model with adduction motion was much higher, reaching 6%, 11%and 21%greater than those of the non-fixation, proximal 2/3 fixation and all-fixation models, respectively. The full-fixation model showed the lowest compressive principal stress and implant movement. Thus, we concluded that the late loosening and subsequent movement of the stem in the long term could be estimated with the cortical bone remodeling method based on a high compressive stress at the bone-implant interface. The change caused at the bone-prosthesis interface by bony or fibrous tissue ingrowth constituted the major factor in determining the extent of cortical bone resorption occurring with clinical loosening and subsequent implant movement.

Propidium iodide staining: a new application in fluorescence microscopy for analysis of cytoarchitecture in adult and developing rodent brain.

PubMed

Hezel, Marcus; Ebrahimi, Fahim; Koch, Marco; Dehghani, Faramarz

2012-10-01

Immunohistochemical visualization of antigens in specimen has evolved to an indispensable technique in biomedical research for investigations of cell morphology and pathology both in bright field and fluorescence microscopy. While there are couple of staining methods that reveal entire cytoarchitecture in bright field microscopy such as Nissl or hemalaun-eosin, there are still limitations in visualizations of cytoarchitecture in fluorescence microscopy. The present study reports a simple staining method that provides the required illustration of cell allocations and cellular composition in fluorescence microscopy in adult and in developing rodent central nervous system using the fluorophore propidium iodide (PI, 5μg/mL). PI is a well-accepted marker for degenerating cells when applied prior to fixation (pre-fixation PI staining). Here, PI was added to the sections after the fixation (post-fixation PI staining). This revised labeling procedure led to similar cytoarchitectural staining patterns in fluorescence microscopy as observed with hemalaun in bright field microscopy. This finding was proven in organotypic hippocampal slice cultures (OHSC) and brain sections obtained from different postnatal developmental stages. Excitotoxically lesioned OHSC subjected to pre-fixation PI staining merely showed brightly labeled condensed nuclei of degenerating neurons. In contrast, post-fixation PI staining additionally revealed extensive labeling of neuronal cell bodies and glial cells within the OHSC, thus allowing visualization of stratification of neuronal layers and cell morphology. Furthermore, post-fixation PI staining was combined with NeuN, calbindin, calretinin, glial fibrillary acidic protein or Griffonia simplicifolia isolectin B4 (IB(4)) in post natal (p1 and p9) and adult rats. In early post-natal brain sections almost all mentioned cellular markers led to an incomplete staining of the native cell organization and resulted in an inaccurate estimation of cell morphology when compared to adult brains. In contrast, post-fixation PI staining allowed investigation of the whole cytoarchitecture independent of the developmental stage. Taken together, post-fixation PI staining provides a detailed insight in the morphology of both developing and adult brain tissues in fluorescence microscopy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Three-dimensional analysis of postoperative returning movement of perioperative condylar displacement after bilateral sagittal split ramus osteotomy for mandibular setback with different fixation methods.

PubMed

Han, Jeong Joon; Hwang, Soon Jung

2015-11-01

This study aimed to evaluate postoperative returning movement of perioperative condylar displacement after bilateral sagittal split ramus osteotomy (BSSRO) depending on a fixation method using three-dimensional (3D) analysis of computed tomography (CT). Twenty-five mandibular prognathic patients (50 condyles) who underwent orthognathic surgery with BSSRO were divided into three groups depending on the fixation method, which consisted of miniplate only (Group A), combined with single bicortical screw (Group B), or with more than one bicortical screw (Group C). CT data taken before, immediately after, and 3 to 6 months after surgery were analyzed. The condyle exhibited mainly lateral bodily displacement and inward and inferior rotation immediately after surgery. The amount of perioperative lateral displacement of the condyle increased according to the increasing number of fixation screws, but the mean displacements were not significantly different among the three groups. During the postoperative follow-up period, the amount of medial returning of the condyle was 102.2% of the intraoperative lateral displacement in Group A. In contrast, Group B and C exhibited partial returning movement by 71.3% and 38.9% of cases, respectively. In conclusion, stronger rigid internal fixation in orthognathic surgery using BSSRO is associated with reduced flexibility of postoperative functional adjustment of displaced condyle to the preoperative condylar position. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Comparative fixation methods of cervical disc arthroplasty versus conventional methods of anterior cervical arthrodesis: serration, teeth, keels, or screws?

PubMed

Cunningham, Bryan W; Hu, Nianbin; Zorn, Candace M; McAfee, Paul C

2010-02-01

Using a synthetic vertebral model, the authors quantified the comparative fixation strengths and failure mechanisms of 6 cervical disc arthroplasty devices versus 2 conventional methods of cervical arthrodesis, highlighting biomechanical advantages of prosthetic endplate fixation properties. Eight cervical implant configurations were evaluated in the current investigation: 1) PCM Low Profile; 2) PCM V-Teeth; 3) PCM Modular Flange; 4) PCM Fixed Flange; 5) Prestige LP; 6) Kineflex/C disc; 7) anterior cervical plate + interbody cage; and 8) tricortical iliac crest. All PCM treatments contained a serrated implant surface (0.4 mm). The PCM V-Teeth and Prestige contained 2 additional rows of teeth, which were 1 mm and 2 mm high, respectively. The PCM Modular and Fixed Flanged devices and anterior cervical plate were augmented with 4 vertebral screws. Eight pullout tests were performed for each of the 8 conditions by using a synthetic fixation model consisting of solid rigid polyurethane foam blocks. Biomechanical testing was conducted using an 858 Bionix test system configured with an unconstrained testing platform. Implants were positioned between testing blocks, using a compressive preload of -267 N. Tensile load-to-failure testing was performed at 2.5 mm/second, with quantification of peak load at failure (in Newtons), implant surface area (in square millimeters), and failure mechanisms. The mean loads at failure for the 8 implants were as follows: 257.4 +/- 28.54 for the PCM Low Profile; 308.8 +/- 15.31 for PCM V-Teeth; 496.36 +/- 40.01 for PCM Modular Flange; 528.03+/- 127.8 for PCM Fixed Flange; 306.4 +/- 31.3 for Prestige LP; 286.9 +/- 18.4 for Kineflex/C disc; 635.53 +/- 112.62 for anterior cervical plate + interbody cage; and 161.61 +/- 16.58 for tricortical iliac crest. The anterior plate exhibited the highest load at failure compared with all other treatments (p < 0.05). The PCM Modular and Fixed Flange PCM constructs in which screw fixation was used exhibited higher pullout loads than all other treatments except the anterior plate (p < 0.05). The PCM VTeeth and Prestige and Kineflex/C implants exhibited higher pullout loads than the PCM Low Profile and tricortical iliac crest (p < 0.05). Tricortical iliac crest exhibited the lowest pullout strength, which was different from all other treatments (p < 0.05). The surface area of endplate contact, measuring 300 mm(2) (PCM treatments), 275 mm(2) (Prestige LP), 250 mm(2) (Kineflex/C disc), 180 mm(2) (plate + cage), and 235 mm(2) (tricortical iliac crest), did not correlate with pullout strength (p > 0.05). The PCM, Prestige, and Kineflex constructs, which did not use screw fixation, all failed by direct pullout. Screw fixation devices, including anterior plates, led to test block fracture, and tricortical iliac crest failed by direct pullout. These results demonstrate a continuum of fixation strength based on prosthetic endplate design. Disc arthroplasty constructs implanted using vertebral body screw fixation exhibited the highest pullout strength. Prosthetic endplates containing toothed ridges (>or= 1 mm) or keels placed second in fixation strength, whereas endplates containing serrated edges exhibited the lowest fixation strength. All treatments exhibited greater fixation strength than conventional tricortical iliac crest. The current study offers insights into the benefits of various prosthetic endplate designs, which may potentially improve acute fixation following cervical disc arthroplasty.

Correlation between loose density and compactibility of granules prepared by various granulation methods.

PubMed

Murakami, H; Yoneyama, T; Nakajima, K; Kobayashi, M

2001-03-23

The objectives of this study were to prepare the lactose granules by various granulation methods using polyethylene glycol 6000 (PEG 6000) as a binder and to evaluate the effects of granulation methods on the compressibility and compactibility of granules in tabletting. Lactose was granulated by seven granulation methods -- four wet granulations including wet massing granulation, wet high-speed mixer granulation, wet fluidized bed granulation and wet tumbling fluidized bed granulation; and three melt granulations including melt high-speed mixer granulation, melt fluidized bed granulation and melt tumbling fluidized bed granulation. The loose density, angle of repose, granule size distribution, mean diameter of granules, and the tensile strength and porosity of tablets were evaluated. The compactibilities of granules were varied by the granulation methods. However, the difference in compactibility of granules could not be explained due to the difference in compressibility, since there was no difference in Heckel plots due to granulation methods. Among their granule properties, the loose density of granules seemed to have a correlation with the tablet strength regardless of the granulation methods.

The Biomechanical Study of Extraforaminal Lumbar Interbody Fusion: A Three-Dimensional Finite-Element Analysis.

PubMed

Yang, Mingjie; Sun, Guixin; Guo, Song; Zeng, Cheng; Yan, Meijun; Han, Yingchao; Xia, Dongdong; Zhang, Jingjie; Li, Xinhua; Xiang, Yang; Pan, Jie; Li, Lijun; Tan, Jun

2017-01-01

Finite-element method was used to evaluate biomechanics stability of extraforaminal lumbar interbody fusion (ELIF) under different internal fixation. The L3-L5 level finite-element model was established to simulate decompression and internal fixation at L4-L5 segment. The intact finite model was treated in accordance with the different internal fixation. The treatment groups were exerted 400 N load and 6 N·m additional force from motion to calculate the angular displacement of L4-L5. The ROMs were smaller in all internal fixation groups than those in the intact model. Furthermore, the ROMs were smaller in ELIF + UPS group than in TLIF + UPS group under all operating conditions, especially left lateral flexion and right rotation. The ROMs were higher in ELIF + UPS group than in TLIF + BPS group. The ROMs of ELIF + UPS + TLFS group were much smaller than those in ELIF + UPS group, and as compared with TLIF + BPS group, there was no significant difference in the range of experimental loading. The biomechanical stability of ELIF with unilateral pedicle screw fixation is superior to that of TLIF with unilateral pedicle screw fixation but lower than that of TLIF with bilateral pedicle screws fixation. The stability of ELIF with unilateral fixation can be further improved by supplementing a translaminar facet screw.

Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

PubMed

Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

2016-08-12

Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs.

Biomechanical monitoring of healing bone based on acoustic emission technology.

PubMed

Hirasawa, Yasusuke; Takai, Shinro; Kim, Wook-Cheol; Takenaka, Nobuyuki; Yoshino, Nobuyuki; Watanabe, Yoshinobu

2002-09-01

Acoustic emission testing is a well-established method for assessment of the mechanical integrity of general construction projects. The purpose of the current study was to investigate the usefulness of acoustic emission technology in monitoring the yield strength of healing callus during external fixation. Thirty-five patients with 39 long bones treated with external fixation were evaluated for fracture healing by monitoring load for the initiation of acoustic emission signal (yield strength) under axial loading. The major criteria for functional bone union based on acoustic emission testing were (1) no acoustic emission signal on full weightbearing, and (2) a higher estimated strength than body weight. The yield strength monitored by acoustic emission testing increased with the time of healing. The external fixator could be removed safely and successfully in 97% of the patients. Thus, the acoustic emission method has good potential as a reliable method for monitoring the mechanical status of healing bone.

Nanotextured Surfaces and Related Methods, Systems, and Uses

NASA Technical Reports Server (NTRS)

Greer, Harold F. (Inventor); Greer, Julia R. (Inventor)

2014-01-01

A method of controlling wetting characteristics is described. Such method includes forming and configuring nanostructures on a surface where controlling of the wetting characteristics is desired. Surfaces and methods of fabricating such surfaces are also described.

Abnormality in face scanning by children with autism spectrum disorder is limited to the eye region: Evidence from multi-method analyses of eye tracking data

PubMed Central

Yi, Li; Fan, Yuebo; Quinn, Paul C.; Feng, Cong; Huang, Dan; Li, Jiao; Mao, Guoquan; Lee, Kang

2012-01-01

There has been considerable controversy regarding whether children with autism spectrum disorder (ASD) and typically developing children (TD) show different eye movement patterns when processing faces. We investigated ASD and age- and IQ-matched TD children's scanning of faces using a novel multi-method approach. We found that ASD children spent less time looking at the whole face generally. After controlling for this difference, ASD children's fixations of the other face parts, except for the eye region, and their scanning paths between face parts were comparable either to the age-matched or IQ-matched TD groups. In contrast, in the eye region, ASD children's scanning differed significantly from that of both TD groups: (a) ASD children fixated significantly less on the right eye (from the observer's view); (b) ASD children's fixations were more biased towards the left eye region; and (c) ASD children fixated below the left eye, whereas TD children fixated on the pupil region of the eye. Thus, ASD children do not have a general abnormality in face scanning. Rather, their abnormality is limited to the eye region, likely due to their strong tendency to avoid eye contact. PMID:23929830

Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part Two: Superior Repositioning Surgery With Bone Allograft.

PubMed

Kilinç, Yeliz; Erkmen, Erkan; Kurt, Ahmet

2016-01-01

In this study, the biomechanical behavior of different fixation methods used to fix the mandibular anterior segment following various amounts of superior repositioning was evaluated by using Finite Element Analysis (FEA). The three-dimensional finite element models representing 3 and 5 mm superior repositioning were generated. The gap in between segments was assumed to be filled by block bone allograft and resignated to be in perfect contact with the mandible and segmented bone. Six different finite element models with 2 distinct mobilization rate including 3 different fixation configurations, double right L (DRL), double left L (DLL), or double I (DI) miniplates with monocortical screws, correspondingly were created. A comparative evaluation has been made under vertical, horizontal and oblique loads. The von Mises and principal maximum stress (Pmax) values were calculated by finite element solver programme. The first part of our ongoing Finite Element Analysis research has been addressed to the mechanical behavior of the same fixation configurations in nongrafted models. In comparison with the findings of the first part of the study, it was concluded that bone graft offers superior mechanical stability without any limitation of mobilization and less stress on the fixative appliances as well as in the bone.

Simple technique to treat pupillary capture after transscleral fixation of intraocular lens.

PubMed

Jürgens, Ignasi; Rey, Amanda

2015-01-01

We describe a simple surgical technique to manage pupillary capture after previous transscleral fixation of an intraocular lens. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Regional and national significance of biological nitrogen fixation by crops in the United States

EPA Science Inventory

Background/Questions/Methods Biological nitrogen fixation by crops (C-BNF) represents one of the largest anthropogenic inputs of reactive nitrogen (N) to land surfaces around the world. In the United States (US), existing estimates of C-BNF are uncertain because of incomplete o...

How successful are mutants in multiplayer games with fluctuating environments? Sojourn times, fixation and optimal switching

PubMed Central

Galla, Tobias

2018-01-01

Using a stochastic model, we investigate the probability of fixation, and the average time taken to achieve fixation, of a mutant in a population of wild-types. We do this in a context where the environment in which the competition takes place is subject to stochastic change. Our model takes into account interactions which can involve multiple participants. That is, the participants take part in multiplayer games. We find that under certain circumstances, there are environmental switching dynamics which minimize the time that it takes for the mutants to fixate. To analyse the dynamics more closely, we develop a method by which to calculate the sojourn times for general birth–death processes in fluctuating environments. PMID:29657810

How successful are mutants in multiplayer games with fluctuating environments? Sojourn times, fixation and optimal switching

NASA Astrophysics Data System (ADS)

Baron, Joseph W.; Galla, Tobias

2018-03-01

Using a stochastic model, we investigate the probability of fixation, and the average time taken to achieve fixation, of a mutant in a population of wild-types. We do this in a context where the environment in which the competition takes place is subject to stochastic change. Our model takes into account interactions which can involve multiple participants. That is, the participants take part in multiplayer games. We find that under certain circumstances, there are environmental switching dynamics which minimize the time that it takes for the mutants to fixate. To analyse the dynamics more closely, we develop a method by which to calculate the sojourn times for general birth-death processes in fluctuating environments.

Collection of Wet-Origin Footwear Impressions on Various Surfaces Using an Electrostatic Dust Print Lifter.

PubMed

Hong, Sungwook; Park, Miseon

2018-01-19

Electrostatic dust print lift method is known to be able to recover only dry-origin footwear impression. However, the wet-origin footwear impression could also be recovered using this method. As the amount of dust accumulated before deposition of the wet-origin footwear impression increased, the intensity of the footwear impression lifted with this method became stronger. If the footwear impression is not affected by moisture after it is made, the 28-h old wet-origin footwear impression could be recovered using this method. The intensity of the lifted footwear impression did not decrease significantly even when the number of sequential steps increased as long as the shoe sole is wet. However, when the moisture on the shoe sole depleted, the intensity of the footwear impression decreased sharply. This method has the advantage of being able to enhance the footwear impression without being affected by the footwear impressions deposited in the past. © 2018 American Academy of Forensic Sciences.

Ilizarov bone transport versus fibular graft for reconstruction of tibial bone defects in children.

PubMed

Abdelkhalek, Mostafa; El-Alfy, Barakat; Ali, Ayman M

2016-11-01

The aim of this study was to compare the results of treatment of segmental tibial defects in the pediatric age group using an Ilizarov external fixator versus a nonvascularized fibular bone graft. This study included 24 patients (age range from 5.5 to 15 years) with tibial bone defects: 13 patients were treated with bone transport (BT) and 11 patients were treated with a nonvascularized fibular graft (FG). The outcome parameters were bone results (union, deformity, infection, leg-length discrepancy) and functional results: external fixation index and external fixation time. In group A (BT), one patient developed refracture at the regenerate site, whereas, in group B (FG), after removal of the external fixator, one of the FGs developed a stress fracture. The external fixator time in group A was 10.7 months (range 8-14.5) versus 7.8 months (range 4-11.5 months) in group B (FG). In group A (BT), one patient had a limb-length discrepancy (LLD), whereas, in group B (FG), three patients had LLD. The functional and bone results of the Ilizarov BT technique were excellent in 23.1 and 30.8%, good in 38.5 and 46.2, fair in 30.8 and 15.4, and poor in 7.6 and 7.6%, respectively. The poor functional result was related to the poor bone result because of prolonged external fixator time resulting in significant pain, limited ankle motion, whereas the functional and bone results of fibular grafting were excellent in 9.1 and 18.2%, good in 63.6 and 45.5%, fair in 18.2 and 27.2%, and poor in 9.1 and 9.1%, respectively. Segmental tibial defects can be effectively treated with both methods. The FG method provides satisfactory results, with early removal of the external fixator. However, it had a limitation in patients with severe infection and those with LLD. Also, it requires a long duration of limb bracing until adequate hypertrophy of the graft. The Ilizarov method has the advantages of early weight bearing, treatment of postinfection bone defect in a one-stage surgery, and the possibility to treat the associated LLD. However, it has a long external fixation time.

Toward FRP-Based Brain-Machine Interfaces—Single-Trial Classification of Fixation-Related Potentials

PubMed Central

Finke, Andrea; Essig, Kai; Marchioro, Giuseppe; Ritter, Helge

2016-01-01

The co-registration of eye tracking and electroencephalography provides a holistic measure of ongoing cognitive processes. Recently, fixation-related potentials have been introduced to quantify the neural activity in such bi-modal recordings. Fixation-related potentials are time-locked to fixation onsets, just like event-related potentials are locked to stimulus onsets. Compared to existing electroencephalography-based brain-machine interfaces that depend on visual stimuli, fixation-related potentials have the advantages that they can be used in free, unconstrained viewing conditions and can also be classified on a single-trial level. Thus, fixation-related potentials have the potential to allow for conceptually different brain-machine interfaces that directly interpret cortical activity related to the visual processing of specific objects. However, existing research has investigated fixation-related potentials only with very restricted and highly unnatural stimuli in simple search tasks while participant’s body movements were restricted. We present a study where we relieved many of these restrictions while retaining some control by using a gaze-contingent visual search task. In our study, participants had to find a target object out of 12 complex and everyday objects presented on a screen while the electrical activity of the brain and eye movements were recorded simultaneously. Our results show that our proposed method for the classification of fixation-related potentials can clearly discriminate between fixations on relevant, non-relevant and background areas. Furthermore, we show that our classification approach generalizes not only to different test sets from the same participant, but also across participants. These results promise to open novel avenues for exploiting fixation-related potentials in electroencephalography-based brain-machine interfaces and thus providing a novel means for intuitive human-machine interaction. PMID:26812487

UK DRAFFT - A randomised controlled trial of percutaneous fixation with kirschner wires versus volar locking-plate fixation in the treatment of adult patients with a dorsally displaced fracture of the distal radius

PubMed Central

2011-01-01

Background Fractures of the distal radius are extremely common injuries in adults. However, the optimal management remains controversial. In general, fractures of the distal radius are treated non-operatively if the bone fragments can be held in anatomical alignment by a plaster cast or orthotic. However, if this is not possible, then operative fixation is required. There are several operative options but the two most common in the UK, are Kirschner-wire fixation (K-wires) and volar plate fixation using fixed-angle screws (locking-plates). The primary aim of this trial is to determine if there is a difference in the Patient-Reported Wrist Evaluation one year following K-wire fixation versus locking-plate fixation for adult patients with a dorsally-displaced fracture of the distal radius. Methods/design All adult patients with an acute, dorsally-displaced fracture of the distal radius, requiring operative fixation are potentially eligible to take part in this study. A total of 390 consenting patients will be randomly allocated to either K-wire fixation or locking-plate fixation. The surgery will be performed in trauma units across the UK using the preferred technique of the treating surgeon. Data regarding wrist function, quality of life, complications and costs will be collected at six weeks and three, six and twelve months following the injury. The primary outcome measure will be wrist function with a parallel economic analysis. Discussion This pragmatic, multi-centre trial is due to deliver results in December 2013. Trial registration Current Controlled Trials ISRCTN31379280 UKCRN portfolio ID 8956 PMID:21914196

A comparison of skeletal stability after mandibular advancement and use of two rigid internal fixation techniques.

PubMed

Blomqvist, J E; Ahlborg, G; Isaksson, S; Svartz, K

1997-06-01

Two different methods of rigid fixation were compared for postoperative stability 6 months after mandibular advancement for treatment of Class II malocclusion. Sixty (30 + 30) patients from two different oral and maxillofacial units treated for a Class II malocclusion by bilateral saggital split osteotomy (BSSO), and two different methods of internal rigid fixation were prospectively investigated. Two groups (S1, n = 15; S2, n = 15) had bicortical noncompressive screws inserted in the gonial area through a transcutaneous approach, and the other two groups (P1, n = 15; P2, n = 15) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively and 6 months after the operation. A computer program was used to superimpose the three cephalograms and to register the mandibular advancement and postoperative change both sagittally and vertically. These were minor differences in the advancement and postoperative changes between the four groups, but statistically no significant difference was shown in either sagittal or vertical directions. However, statistically verified differences proved that increasing age was associated with a smaller amount of postsurgical relapse. Low-angle cases (ML/NSL < 25 degrees) had a bigger amount of surgical (P = .0008) and postsurgical (P = .0195) movement compared with the patients in the high-angle group (ML/NSL < 38 degrees). Using a multiple regression test, a positive correlation was also shown between the amount of surgical advancement and the amount of postsurgical instability (P = .018). This prospective dual-center study indicates that the two different methods of internal rigid fixation after surgical advancement of the mandible by BSSO did not significantly differ from each other, and it is up to the individual operator to choose the method for internal rigid fixation.

Livestock waste-to-bioenergy generation opportunities.

PubMed

Cantrell, Keri B; Ducey, Thomas; Ro, Kyoung S; Hunt, Patrick G

2008-11-01

The use of biological and thermochemical conversion (TCC) technologies in livestock waste-to-bioenergy treatments can provide livestock operators with multiple value-added, renewable energy products. These products can meet heating and power needs or serve as transportation fuels. The primary objective of this work is to present established and emerging energy conversion opportunities that can transform the treatment of livestock waste from a liability to a profit center. While biological production of methanol and hydrogen are in early research stages, anaerobic digestion is an established method of generating between 0.1 to 1.3m3m(-3)d(-1) of methane-rich biogas. The TCC processes of pyrolysis, direct liquefaction, and gasification can convert waste into gaseous fuels, combustible oils, and charcoal. Integration of biological and thermal-based conversion technologies in a farm-scale hybrid design by combining an algal CO2-fixation treatment requiring less than 27,000m2 of treatment area with the energy recovery component of wet gasification can drastically reduce CO2 emissions and efficiently recycle nutrients. These designs have the potential to make future large scale confined animal feeding operations sustainable and environmentally benign while generating on-farm renewable energy.

First metatarsal-phalangeal joint arthrodesis: a biomechanical assessment of stability.

PubMed

Politi, Joel; John, Hayes; Njus, Glen; Bennett, Gordon L; Kay, David B

2003-04-01

First metatarsal phalangeal joint (MTP) arthrodesis is a commonly performed procedure for the treatment of hallux rigidus, severe and recurrent bunion deformities, rheumatoid arthritis and other less common disorders of the joint. There are different techniques of fixation of the joint to promote arthrodesis including oblique lag screw fixation, lag screw and dorsal plate fixation, crossed Kirschner wires, dorsal plate fixation alone and various types of external fixation. Ideally the fixation method should be reproducible, lead to a high rate of fusion, and have a low incidence of complications. In the present study, we compared the strength of fixation of five commonly utilized techniques of first MTP joint arthrodesis. These were: 1. Surface excision with machined conical reaming and fixation with a 3.5 mm cortical interfragmentary lag screw. 2. Surface excision with machined conical reaming and fixation with crossed 0.062 Kirschner wires. 3. Surface excision with machined conical reaming and fixation with a 3.5 mm cortical lag screw and a four hole dorsal miniplate secured with 3.5 mm cortical screws. 4. Surface excision with machined conical reaming and fixation with a four hole dorsal miniplate secured with 3.5 mm cortical screws and no lag screw. 5. Planar surface excision and fixation with a single oblique 3.5 mm interfragmentary cortical lag screw. Testing was done on an Instron materials testing device loading the first MTP joint in dorsiflexion. Liquid metal strain gauges were placed over the joint and micromotion was detected with varying loads and cycles. The most stable technique was the combination of machined conical reaming and an oblique interfragmentary lag screw and dorsal plate. This was greater than two times stronger than an oblique lag screw alone. Dorsal plate alone and Kirschner wire fixation were the weakest techniques. First MTP fusion is a commonly performed procedure for the treatment of a variety of disorders of the first MTP joint. The most stable technique for obtaining fusion in this study was the combination of an oblique lag screw and a dorsal plate. This should lead to higher rates of arthrodesis.

Glue versus suture for mesh fixation in inguinal hernia repair.

PubMed

Chandrasekar, Shruthi; Jeyakumar, S; Ganapathy, Tharun

2018-03-22

Inguinal hernia is one of the most common surgical problem presenting to the surgical OPD. Surgery is the mainstay of treatment for inguinal hernia today. Surgery for inguinal hernia has undergone a great evolution over a period of several centuries. Lichenstein's tension free hernioplasty is the one of the first surgeries taught to a surgical resident. The main aim of surgeries in this era is to give the best possible results with the least possible pain, scar and time. This has given rise to so many modifications to the classical Lichenstein's procedure and also to laparoscopic hernioplasty. Pain after inguinal hernia surgery is found to be debilitating and altering the quality of life in several patients, which has been attributed to the traumatic fixation of the mesh with sutures. This has paved way to the development of various atraumatic methods of fixation, tissue glue is one such development. Hence this study, to compare traumatic and atraumatic methods of mesh fixation in inguinal hernia repair. The aim of this study was to compare suture fixation versus tissue glue fixation of the mesh in inguinal hernia repair. Primary objective was to compare the immediate and chronic post-operative pain. Secondary objective was to compare the time taken for the procedure by the two methods in use and also to compare the presence of any complications. and methodology: This study was done in the General Surgery department of XXX hospital, medical college and research centre, kattangulathur after Ethics committee clearance. It is a single blinded study. The study was done on 51 patients consenting for the study and meeting the inclusion criterias from the period of March 2016 to August 2017 out of which 26 were selected for glue mesh fixation and 25 for suture mesh fixation according to simple randomization. The suture group patients underwent classical Lichenstein's tension free hernioplasty and the glue group underwent Lichenstein's hernioplasty with glue where dots of glue were used to fix the mesh instead of sutures. The tissue glue used in this study was N Butyl- 2 - Cyanoacrylate. All patients in the study underwent surgery only by one group of surgeons to maintain homogeneity and were observed in the hospital for 72 h. A note of the pain on VAS scale was made at 12, 24, 48, 72 h, 1 week, 1 month, 3 months and 6 months. Operative time and any complications were also recorded. Results developed using SPSS software show that there is a significant difference in the time taken by both the methods, with glue taking a significantly lower time than sutures. Significance is also seen in the difference in the immediate and chronic post-operative pain between both the groups. However the complication rates in both the groups were found to be the same. It can thus be concluded from this study that tissue glue mesh fixation is superior to suture mesh fixation in open inguinal repair in terms of operative time, immediate and chronic post-operative time. Copyright © 2018. Published by Elsevier Ltd.

Strength analysis of clavicle fracture fixation devices and fixation techniques using finite element analysis with musculoskeletal force input.

PubMed

Marie, Cronskär

2015-08-01

In the cases, when clavicle fractures are treated with a fixation plate, opinions are divided about the best position of the plate, type of plate and type of screw units. Results from biomechanical studies of clavicle fixation devices are contradictory, probably partly because of simplified and varying load cases used in different studies. The anatomy of the shoulder region is complex, which makes it difficult and expensive to perform realistic experimental tests; hence, reliable simulation is an important complement to experimental tests. In this study, a method for finite element simulations of stresses in the clavicle plate and bone is used, in which muscle and ligament force data are imported from a multibody musculoskeletal model. The stress distribution in two different commercial plates, superior and anterior plating position and fixation including using a lag screw in the fracture gap or not, was compared. Looking at the clavicle fixation from a mechanical point of view, the results indicate that it is a major benefit to use a lag screw to fixate the fracture. The anterior plating position resulted in lower stresses in the plate, and the anatomically shaped plate is more stress resistant and stable than a regular reconstruction plate.

SPIRE spinous process stabilization plate: biomechanical evaluation of a novel technology. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2005.

PubMed

Wang, Jeremy C; Spenciner, David; Robinson, James C

2006-02-01

The authors studied the biomechanical properties of a novel spinous process stabilization plate (CD HORIZON SPIRE Spinal System) and present the results in comparison with those of other posterior fixation methods. Ten functional cadaveric lumbar segments were subjected to nondestructive quasistatic loading forces in 10 different conditions: intact, destabilized (discectomy), fitted with spinous process plate (SPP) alone, with anterior-column support (ACS) alone, ACS with SPP, ACS with posterior translaminar facet screw (PTFS) fixation, ACS with unilateral pedicle screw and rod (UPSR) fixation, ACS with bilateral pedicle screw and rod (BPSR) fixation, UPSR alone, or BPSR alone. Stiffness and range of motion (ROM) data were compared using a repeated-measures, one-way analysis of variance. The construct with greatest mean limitation of flexion-extension ROM was ACS/SPP at 4.14 degrees whereas it was 5.75 degrees for ACS/UPSR fixation, 5.03 degrees for ACS/BPSR fixation, and 10.13 degrees for the intact spine. The SPIRE plate alone also provided greater flexion and extension stiffness, with less ROM than other posterior stabilization options. Fixation with BPSR with or without ACS resulted in the stiffest construct in lateral bending and axial rotation. The SPP and UPSR fixation groups were equivalent in resisting lateral bending and axial rotation forces with or without ACS. The SPIRE plate effectively stabilized the spine, and the test results compare favorably with other fixation techniques that are more time consuming to perform and have greater inherent risks.

Mechanical evaluation of the SLM fabricated, stiffness-matched, mandibular bone fixation plates

NASA Astrophysics Data System (ADS)

Jahadakbar, Ahmadreza; Shayesteh Moghaddam, Narges; Amerinatanzi, Amirhesam; Dean, David; Elahinia, Mohammad

2018-03-01

The standard of the care for the treatment of mandibular segmental defects is the use of Ti-6Al-4V bone fixation plates and screws to immobilize the grafted bone and the host mandible. While Ti-6Al-4V bone fixation plates provide strong immobilization during the healing period, they may disturb the stress distribution in the repaired mandible. The highly stiff Ti-6Al-4V fixation carries a great portion of the load which was previously borne by the mandible, and stress shielding may occur on the surrounding cortical bone. Based on the bone remodeling theory, stress shielding causes bone resorption in the effected region and may eventually lead to the failure of the surgical reconstruction. To address this issue, we have developed a new generation of the patient-specific, porous NiTi bone fixation plates which benefit from stiffness-matching of the adjacent bone. Using the CT scan data of the patient's defective mandible, the geometry for the required bone fixation plates is designed and the stiffness of the surrounding regions is measured. By introducing specific level and type of porosity to the bone fixation plate, its stiffness can be tuned. Finite Element simulations has verified the reduced level of stress shielding on the reconstructed mandible, in case of using the proposed bone fixation plates. Selective Lase Sintering has been used for fabrication of the porous NiTi bone fixation plates with six different levels of stiffness. Finite element simulations, and mechanical tests have been done to verify the performance of the fabricated parts resulting from our design and fabrication method.

Increased wound complication with intramedullary screw fixation of clavicle fractures: Is it thermal necrosis?

PubMed

Domos, Peter; Tytherleigh-Strong, Graham; Van Rensburg, Lee

2017-01-01

Adult mid-shaft clavicle fractures are common injuries. For displaced fractures, open reduction with plate or intramedullary (IM) fixation is the widely used techniques. All methods have their own potential drawbacks, especially related to local soft tissue complications. There is little information about outcome and management of local wound complications after clavicle fracture fixations. Ninety-seven patients underwent open reduction and internal fixation, 17 were treated with IM screw fixation and 80 with plate fixation. Wound complication occurred in eight patients (8.2%) and rates differed significantly between IM and plate fixations (29.4% vs. 3.8%). Patients were assessed on average 58.3 months with visual analogue pain scores (VASs), Oxford Shoulder Score (OSS), and QuickDash (QD) score. Five patients had wound breakdown and three patients had wound erythema. In seven patients with stable fixation, it was possible to "dress and suppress" with average 3 weeks of oral antibiotics. One patient had unstable fixation and required longer antibiotic treatment with early screw removal. One patient developed a chronic discharging wound, requiring debridement and later plate removal. At final follow-up, all wounds remained healed, bony union was achieved in all. The average scores were: VAS 1, OSS 46, and QD 4.5. Good function with dry healed wound and united clavicle can be achieved. Further studies are required to investigate the difference in soft tissue complication rates, which may be due to the IM technique of retrograde drilling with a guide wire and due to aseptic thermal bone necrosis, rather than true infection.

Nitrogen fixation in biological soil crusts from southeast Utah, USA

USGS Publications Warehouse

Belnap, Jayne

2002-01-01

Biological soil crusts can be the dominant source of N for arid land ecosystems. We measured potential N fixation rates biweekly for 2 years, using three types of soil crusts: (1) crusts whose directly counted cells were >98% Microcoleus vaginatus (light crusts); (2) crusts dominated by M. vaginatus, but with 20% or more of the directly counted cells represented by Nostoc commune and Scytonema myochrous (dark crusts); and (3) the soil lichen Collema sp. At all observation times, Collema had higher nitrogenase activity (NA) than dark crusts, which had higher NA than light crusts, indicating that species composition is critical when estimating N inputs. In addition, all three types of crusts generally responded in a similar fashion to climate conditions. Without precipitation within a week of collection, no NA was recorded, regardless of other conditions being favorable. Low (<1°C) and high (>26°C) temperatures precluded NA, even if soils were moist. If rain or snow melt had occurred 3 or less days before collection, NA levels were highly correlated with daily average temperatures of the previous 3 days (r2=0.93 for Collema crusts; r2=0.86 for dark crusts and r2=0.83 for light crusts) for temperatures between 1°C and 26°C. If a precipitation event followed a long dry period, NA levels were lower than if collection followed a time when soils were wet for extended periods (e.g., winter). Using a combination of data from a recording weather datalogger, time-domain reflectometry, manual dry-down curves, and N fixation rates at different temperatures, annual N input from the different crust types was estimated. Annual N input from dark crusts found at relatively undisturbed sites was estimated at 9 kg ha–1 year–1. With 20% cover of the N-fixing soil lichen Collema, inputs are estimated at 13 kg ha–1 year–1. N input from light crusts, generally indicating soil surface disturbance, was estimated at 1.4 kg ha–1 year–1. The rates in light crusts are expected to be highly variable, as disturbance history will determine cyanobacterial biomass and therefore N fixation rates.

The effect of B{sub 2}O{sub 3} flux on growth NLBCO superconductor by solid state reaction and wet-mixing methods

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

Suharta, W. G., E-mail: wgsuharta@gmail.com; Wendri, N.; Ratini, N.

The synthesis of B{sub 2}O{sub 3} flux substituted NLBCO superconductor NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂} has been done using solid state reaction and wet-mixing methods in order to obtain homogeneous crystals and single phase. From DTA/TGA characteritations showed the synthesis process by wet-mixing requires a lower temperature than the solid state reaction in growing the superconductor NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂}. Therefore, in this research NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂} sample calcinated at 650°C for wet-mixing method and 820°C for solid state reaction methods. The all samples was sintered at 950°C for ten hours. Crystallinity of the sample was confirmedmore » using X-ray techniques and generally obtained sharp peaks that indicates the sample already well crystallized. Search match analyses for diffraction data gave weight fractions of impurity phase of the solid state reaction method higher than wet-mixing method. In this research showed decreasing the price of the lattice parameter about 1% with the addition of B{sub 2}O{sub 3} flux for the both synthesis process and 2% of wet mixing process for all samples. Characterization using scanning electron microscopy (SEM) showed the distribution of crystal zise for wet-mixing method more homogeneous than solid state reaction method, with he grain size of samples is around 150–250 nm. The results of vibrating sample magnetometer (VSM) showed the paramagnetic properties for all samples.« less

Detecting central fixation by means of artificial neural networks in a pediatric vision screener using retinal birefringence scanning.

PubMed

Gramatikov, Boris I

2017-04-27

Reliable detection of central fixation and eye alignment is essential in the diagnosis of amblyopia ("lazy eye"), which can lead to blindness. Our lab has developed and reported earlier a pediatric vision screener that performs scanning of the retina around the fovea and analyzes changes in the polarization state of light as the scan progresses. Depending on the direction of gaze and the instrument design, the screener produces several signal frequencies that can be utilized in the detection of central fixation. The objective of this study was to compare artificial neural networks with classical statistical methods, with respect to their ability to detect central fixation reliably. A classical feedforward, pattern recognition, two-layer neural network architecture was used, consisting of one hidden layer and one output layer. The network has four inputs, representing normalized spectral powers at four signal frequencies generated during retinal birefringence scanning. The hidden layer contains four neurons. The output suggests presence or absence of central fixation. Backpropagation was used to train the network, using the gradient descent algorithm and the cross-entropy error as the performance function. The network was trained, validated and tested on a set of controlled calibration data obtained from 600 measurements from ten eyes in a previous study, and was additionally tested on a clinical set of 78 eyes, independently diagnosed by an ophthalmologist. In the first part of this study, a neural network was designed around the calibration set. With a proper architecture and training, the network provided performance that was comparable to classical statistical methods, allowing perfect separation between the central and paracentral fixation data, with both the sensitivity and the specificity of the instrument being 100%. In the second part of the study, the neural network was applied to the clinical data. It allowed reliable separation between normal subjects and affected subjects, its accuracy again matching that of the statistical methods. With a proper choice of a neural network architecture and a good, uncontaminated training data set, the artificial neural network can be an efficient classification tool for detecting central fixation based on retinal birefringence scanning.

Glycogen in the Nervous System. I; Methods for Light and Electron Microscopy

NASA Technical Reports Server (NTRS)

Estable, Rosita F. De; Estable-Puig, J. F.; Miquel, J.

1964-01-01

'l'he relative value of different methods for combined light and electron microscopical studies of glycogen in the nervous tissue was investigated. Picroalcoholic fixatives preserve glycogen in a considerable amount but give an inadequate morphological image of glycogen distribution and are unsuitable for ultrastructural studies. Fixation by perfusion, with Dalton's chromeosmic fluid seems adequate for ultrastructural cytochemistry of glycogen. Furthermore it permits routine paraffin embedding of brain slices adjacent to those used for electron microscopy. Dimedone blocking is a necessary step for a selective staining of glycogen with PAS after osmic fixation. Enzymatic removal of glycogen in osmic fixed nervous tissue can be done In paraffin-embedded tissue. It can also be performed in glycolmethacrylate-embedded tissue without removal of the embedding medium. Paraphenylenediamine stains glycogen following periodic acid oxidation.

Complete Numerical Solution of the Diffusion Equation of Random Genetic Drift

PubMed Central

Zhao, Lei; Yue, Xingye; Waxman, David

2013-01-01

A numerical method is presented to solve the diffusion equation for the random genetic drift that occurs at a single unlinked locus with two alleles. The method was designed to conserve probability, and the resulting numerical solution represents a probability distribution whose total probability is unity. We describe solutions of the diffusion equation whose total probability is unity as complete. Thus the numerical method introduced in this work produces complete solutions, and such solutions have the property that whenever fixation and loss can occur, they are automatically included within the solution. This feature demonstrates that the diffusion approximation can describe not only internal allele frequencies, but also the boundary frequencies zero and one. The numerical approach presented here constitutes a single inclusive framework from which to perform calculations for random genetic drift. It has a straightforward implementation, allowing it to be applied to a wide variety of problems, including those with time-dependent parameters, such as changing population sizes. As tests and illustrations of the numerical method, it is used to determine: (i) the probability density and time-dependent probability of fixation for a neutral locus in a population of constant size; (ii) the probability of fixation in the presence of selection; and (iii) the probability of fixation in the presence of selection and demographic change, the latter in the form of a changing population size. PMID:23749318

The surface topography of the choroid plexus. Environmental, low and high vacuum scanning electron microscopy.

PubMed

Mestres, Pedro; Pütz, Norbert; Garcia Gómez de Las Heras, Soledad; García Poblete, Eduardo; Morguet, Andrea; Laue, Michael

2011-05-01

Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characteristic morphology of the choroid plexus cells at a high resolution and served as reference. With low vacuum ESEM of dried but uncoated samples the structure appeared well preserved but charging was a problem. It could be reduced by a short beam dwell time and averaging of images or by using the backscattered electron detector instead of the gaseous secondary electron detector. However, resolution was lower than with conventional SEM. Wet mode imaging was only possible with tissue that had been stabilized by fixation. Not all surface details (e.g. microvilli) could be visualized and other structures, like the cilia, were deformed. In summary, ESEM is an additional option for the imaging of bio-medical samples but it is problematic with regard to resolution and sample stability during imaging. Copyright © 2011 Elsevier GmbH. All rights reserved.

Visual Afterimages of Emotional Faces in High Functioning Autism

ERIC Educational Resources Information Center

Rutherford, M. D.; Troubridge, Erin K.; Walsh, Jennifer

2012-01-01

Fixating an emotional facial expression can create afterimages, such that subsequent faces are seen as having the opposite expression of that fixated. Visual afterimages have been used to map the relationships among emotion categories, and this method was used here to compare ASD and matched control participants. Participants adapted to a facial…

Spinopelvic Fixation of Sacroiliac Joint Fractures and Fracture-Dislocations: A Clinical 8 Years Follow-Up Study.

PubMed

Sobhan, Mohammad R; Abrisham, Seyed Mohammad J; Vakili, Mahmood; Shirdel, Saeed

2016-10-01

Pelvic ring injuries and sacroiliac dislocations have significant impacts on patient's quality of life. Several techniques have been described for posterior pelvic fixation. The current study has been designed to evaluate the spinopelvic method of fixation for sacroiliac fractures and fracture-dislocations. Between January 2006 and December 2014, 14 patients with sacroiliac joint fractures, dislocation and fracture-dislocation were treated by Spinopelvic fixation at Shahid Sadoughi Training Hospital, Yazd, Iran. Patients were seen in follow up, on average, out to 32 months after surgery. Computed tomographic (CT) scans of patients with sacral fractures were reviewed to determine the presence of injuries. A functional assessment of the patients was performed using Majeed's score. Patient demographics, reduction quality, loss of fixation, outcomes and complications, return to activity, and screw hardware characteristics are described. The injury was unilateral in 11 (78.5%) patients and bilateral in 3 (21.5%). Associated injuries were present in all patients, including fractures, dislocation and abdominal injuries. Lower limb length discrepancy was less than 10 mm in all patients except two. Displacement, as a measure of quality of reduction was less than 5 mm in 13 patients. The mean Majeed score was 78/100. Wound infection and hardware failure were observed in 3 (21.4%) and 1 (7.1%) cases, respectively. In this study most patients (85%) return to work postoperatively. According to the findings, spinopelvic fixation is a safe and effective technique for treatment of sacroiliac injuries. This method can obtain early partial to full weight bearing and possibly reduce the complications.

Implant Removal after Percutaneous Short Segment Fixation for Thoracolumbar Burst Fracture : Does It Preserve Motion?

PubMed Central

Kim, Hyeun Sung; Ju, Chang Il; Wang, Hui Sun; Lee, Sung Myung; Kim, Dong Min

2014-01-01

Objective The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation. Methods Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed. Results Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobb's method) in flexion and extension in Group A was 10.5° (19.5/9.0°) at last follow-up, and in Group B was 10.2° (18.8/8.6°) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless. Conclusion Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures. PMID:24653799

A Prospective Study of Distal Metatarsal Chevron Osteotomies with K-Wire Fixations to Treat Hallux Valgus Deformities.

PubMed

Baig, M N; Baig, Usman; Tariq, Ali; Din, Robert

2017-09-20

Introduction Hallux valgus is one of the most common forefoot deformities worldwide. Females are affected more often than males. The three most common clinical symptoms are the painful bunion, transfer metatarsalgia, and hammer or claw toes. Methods This case series consisted of 20 patients who had chevron osteotomy from January 2015 to January 2016. The clinical assessment was measured by The American Orthopedic Foot and Ankle Score (AOFAS), and radiologic assessment was determined by preoperative and postoperative hallux valgus angle (HVA) and intermetatarsal angle (IMA). Results The patients' mean age was 56 years. Out of 20 patients, 19 were female, and one was male. The mean AOFAS improved from 51 preoperatively to 82 postoperatively. The HVA improved from 26° preoperatively to 14°. There were five complications including four Kirschner (K)-wire complications. Conclusion Distal chevron osteotomy is a reliable and time-tested procedure. The K-wire fixation has a relatively high complication rate. We planned to use other methods of fixation and then compared them with K-wires fixation results for future studies.

A Prospective Study of Distal Metatarsal Chevron Osteotomies with K-Wire Fixations to Treat Hallux Valgus Deformities

PubMed Central

Baig, Usman; Tariq, Ali; Din, Robert

2017-01-01

Introduction Hallux valgus is one of the most common forefoot deformities worldwide. Females are affected more often than males. The three most common clinical symptoms are the painful bunion, transfer metatarsalgia, and hammer or claw toes. Methods This case series consisted of 20 patients who had chevron osteotomy from January 2015 to January 2016. The clinical assessment was measured by The American Orthopedic Foot and Ankle Score (AOFAS), and radiologic assessment was determined by preoperative and postoperative hallux valgus angle (HVA) and intermetatarsal angle (IMA). Results The patients’ mean age was 56 years. Out of 20 patients, 19 were female, and one was male. The mean AOFAS improved from 51 preoperatively to 82 postoperatively. The HVA improved from 26° preoperatively to 14°. There were five complications including four Kirschner (K)-wire complications. Conclusion Distal chevron osteotomy is a reliable and time-tested procedure. The K-wire fixation has a relatively high complication rate. We planned to use other methods of fixation and then compared them with K-wires fixation results for future studies. PMID:29167752

Vacuum sealing drainage therapy in the presence of an external fixation device

PubMed Central

Sun, Dahui; Ju, Weina; Wang, Tiejun; Yu, Tiecheng; Qi, Baochang

2016-01-01

Abstract Rationale: Vacuum sealing drainage (VSD) is widely utilized for treating traumatic wounds. Patient concerns: It is particularly difficult and time consuming to use in combination with an external fixator. Diagnoses: This is because the hardware or pins used for fixation interfere with maintaining a seal, resulting in poor adhesion and subsequent air leakage. Interventions: To resolve this problem, we have devised a new method for sealing the wound dressing, while maintaining the required vacuum.When using this technique, a rubber strip is wrapped around each pin in 3 circles outside the plastic drape, and then tightly tied. Outcomes: After completing this procedure, a vacuum is obtained, and any air leakage stops. We employed this technique to treat a cohort of patients in our department over a period of two years, and obtained good healing of soft tissue without air leakage, as well as good clinical outcomes. Lessons: We have observed that patients treated with this method experienced good clinical outcomes without air leakage, and we recommend its use in treating cases where an external fixation device is present. PMID:27861393

Free flap reconstructions of tibial fractures complicated after internal fixation.

PubMed

Nieminen, H; Kuokkanen, H; Tukiainen, E; Asko-Seljavaara, S

1995-04-01

The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

Biomechanical study of different fixation techniques for the treatment of sacroiliac joint injuries using finite element analyses and biomechanical tests.

PubMed

Lee, Chian-Her; Hsu, Ching-Chi; Huang, Po-Yuang

2017-08-01

The pelvis is one of the most stressed areas of the human musculoskeletal system due to the transfer of truncal loads to the lower extremities. Sacroiliac joint injury may lead to abnormal joint mechanics and an unstable pelvis. Various fixation techniques have been evaluated and discussed. However, it may be difficult to investigate each technique due to variations in bone quality, bone anatomy, fracture pattern, and fixation location. Additionally, the finite element method is one useful technology that avoids these variations. Unfortunately, most previous studies neglected the effects of the lumbar spine and femurs when they investigated the biomechanics of pelvises. Thus, the aim of this study was to investigate the biomechanical performance of intact, injured, and treated pelvises using numerical and experimental approaches. Three-dimensional finite element models of the spine-pelvis-femur complex with and without muscles and ligaments were developed. The intact pelvis, the pelvis with sacroiliac joint injury, and three types of pelvic fixation techniques were analyzed. Concurrently, biomechanical tests were conducted to validate the numerical outcomes using artificial pelvises. Posterior iliosacral screw fixation showed relatively better fixation stability and lower risks of implant failure and pelvic breakage than sacral bar fixation and a locking compression plate fixation. The present study can help surgeons and engineers understand the biomechanics of intact, injured, and treated pelvises. Both the simulation technique and the experimental setup can be applied to investigate different pelvic injuries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of nitrogen balance in agroecosystems.

PubMed

Sainju, Upendra M

2017-01-01

Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen outputs include N removal in crop grain and biomass and N losses through leaching, denitrification, volatilization, surface runoff, erosion, gas emissions, and plant senescence. Nitrogen balance, which is the difference between N inputs and outputs, can be reflected in changes in soil total (organic + inorganic) N during the course of the experiment duration due to N immobilization and mineralization. While increased soil N retention and mineralization can enhance crop yields and decrease N fertilization rate, reduced N losses through N leaching and gas emissions (primarily NH 4 and NO x emissions, out of which N 2 O is a potent greenhouse gas) can improve water and air quality. •This paper discusses measurements and estimations (for non-measurable parameters due to complexity) of all inputs and outputs of N as well as changes in soil N storage during the course of the experiment to calculate N balance.•The method shows N flows, retention in the soil, and losses to the environment from agroecosystems.•The method can be used to measure agroecosystem performance and soil and environmental quality from agricultural practices.

Fixation-free rehalogenating bleached reflection holograms recorded on BB-640 plates

NASA Astrophysics Data System (ADS)

Neipp, C.; Pascual, I.; Beléndez, A.

2000-08-01

Fixation-free rehalogenating bleaching is an interesting process for the production of phase reflection holograms. The shrinkage of the emulsion is reduced in comparison with other bleaching methods (reversal bleaching or rehalogenating bleaching with a fixation step), which is particularly interesting in the case of reflection holograms. In this communication, we present experimental results for fixation-free rehalogenating bleached holograms derived from the novel BB-640 emulsion, a red-sensitive ultra-fine grain emulsion from Holographic Recording Technologies using an R-10 type bleach bath. The influence of the potassium bromide concentrations in the bleach solution on the final quality of the holograms is also studied. The concentrations of the different components of the bleach solution are adjusted to obtain the highest diffraction efficiencies. A high diffraction efficiency of 72% is obtained.

Wet refractivity tomography with an improved Kalman-Filter method

NASA Astrophysics Data System (ADS)

Cao, Yunchang; Chen, Yongqi; Li, Pingwha

2006-10-01

An improved retrieval method, which uses the solution with a Gaussian constraint as the initial state variables for the Kalman Filtering (KF) method, was developed to retrieve the wet refractivity profiles from slant wet delays (SWD) extracted by the double-differenced (DD) GPS method. The accuracy of the GPS-derived SWDs is also tested in this study against the measurements of a water vapor radiometer (WVR) and a weather model. It is concluded that the GPS-derived SWDs have similar accuracy to those measured with WVR and are much higher in quality than those derived from the weather model used. The developed method is used to retrieve the 3D wet refractivity distribution in the Hong Kong region. The retrieved profiles agree well with the radiosonde observations, with a difference of about 4 mm km-1 in the low levels. The accurate profiles obtained with this method are applicable in a number of meteorological applications.

Mechanical rigidity of the Ortho-SUV frame compared to the Ilizarov frame in the correction of femoral deformity.

PubMed

Skomoroshko, Petr V; Vilensky, Victor A; Hammouda, Ahmed I; Fletcher, Matt D A; Solomin, Leonid N

2015-04-01

The Ortho-SUV frame (OSF) is a novel hexapod circular external fixator which draws upon the innovation of the Ilizarov method and the advantages of hexapod construction in the three-dimensional control of bone segments. Stability of fixation is critical to the success or failure of an external circular fixator for fracture or osteotomy healing. In vitro biomechanical modelling study was performed comparing the stability of the OSF under load in both original form and after dynamisation to the Ilizarov fixator in all zones of the femur utilising optimal frame configuration. A superior performance of the OSF in terms of resistance to deforming forces in both original and dynamised forms over that of the original Ilizarov fixator was found. The OSF shows higher rigidity than the Ilizarov in the control of forces acting upon the femur. This suggests better stabilisation of femoral fractures and osteotomies and thus improved healing with a reduced incidence of instability-related bone segment deformity, non-union and delayed union.

Miniplate fixation of Le Fort I osteotomies.

PubMed

Rosen, H M

1986-12-01

The use of rigid, internal, three-dimensional fixation using vitallium bone plates in 28 consecutive Le Fort I osteotomies is presented. A minimum follow-up period of 6 months was required for inclusion in this patient group. Maxillary movements included advancements (17), intrusions (9), lengthenings (5), and retrusions (2). The majority of maxillae were moved in more than one plane of space. Technical details, complications, and relapse potential are discussed. Advantages of rigid plate fixation include marked reductions in the length of intermaxillary fixation with light training elastics only. Immediate postoperative airway problems are thereby eliminated. Six months of follow-up would appear to indicate a low potential for osseous relapse when compared to wire osteosynthesis, regardless of the direction of maxillary movement. The major disadvantage is the decreased ability of postoperative orthodontics to move dento-osseous segments if skeletal occlusal disharmony persists postoperatively. For this reason, close attention to preoperative planning and operative technique is critical for the success of this fixation method.

Posterior cervical fixation for fracture and degenerative disc disease.

PubMed

An, H S; Coppes, M A

1997-02-01

There are numerous newer techniques that have been developed for the internal fixation of the cervical spine in recent years. Wiring techniques are still appropriate for posterior stabilization of the cervical spine. The halo vest is still widely used for the conservative management of cervical fractures and for postoperative external immobilization. The authors stress that the surgical indications for more modern rigid implants should be adhered to strictly. These implants also should be selected by weighing their advantages versus potential risks. In the upper cervical spine, the surgeon may choose traditional wiring methods and newer C1-C2 screw fixation, occipitocervical plate fixation. For the lower cervical spine, triple wiring technique or lateral mass plating may be used. The surgeon must choose an appropriate device based on the mechanism of injury, pathoanatomy of the lesion, and familiarity with the device, keeping in mind that the goals of internal fixation are stabilization, reduction and maintenance of alignment, early rehabilitation and perhaps enhancement of fusion rates, and avoidance of use of an external halo vest.

[Preparation and evaluation of taste masked orally disintegrating tablets with granules made by the wet granulation method].

PubMed

Kawano, Yayoi; Ito, Akihiko; Sasatsu, Masanaho; Machida, Yoshiharu; Onishi, Hiraku

2010-12-01

Using furosemide (FU) as a model drug, we examined the wet granulation method as a way to improve the taste masking and physical characteristics of orally disintegrating tablets (ODTs). In the wet granulation method, yogurt powder (YO) was used as a corrective and maltitol (MA) was used as a binding agent. The taste masked FU tablets were prepared using the direct compression method. Microcrystalline cellulose (Avicel® PH-302) and mannitol were added as excipients at a mixing ratio of 1/1 by weight. Based on the results of sensory test on taste, the prepared granules markedly improved the taste of FU, and a sufficient masking effect was obtained at the YO/FU ratio of 1 or more. Furthermore, it was found that the masking effect achieved by YO granules made with the wet granulation method was similar to or better than that produced by the granules made with dry granulation method. All types of tablets displayed sufficient hardness (over 3.5×10(-2) kN), and rapidly disintegrating tablets were obtained with YO granules produced at a mixing ratio of FU/YO=1/1, which disintegrated within 20 s. Disintegration time lengthened as the mixing ratio of YO to FU increased. In the mixing ratio of FU/YO=1/1, the hardness of tablets with granules made by the wet granulation method exceeded that of tablets with granules made by the dry granulation method, with minimal differences in disintegration time. The hardness and disintegration time of the tablets with granules made by the wet granulation method could be controlled by varying the compression force. In conclusion, YO was found to be a useful additive for masking unpleasant tastes. FU ODTs with improved taste, rapid disintegration and greater hardness could be prepared with YO-containing granules made by the wet granulation method using MA as a binding agent.

Wet cooling towers: rule-of-thumb design and simulation

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

Leeper, Stephen A.

1981-07-01

A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization. The theory of heat exchange in wet cooling towers is briefly summarized. The Merkel equation (the fundamental equation of heat transfer in wet cooling towers) is presented and discussed. The cooling tower fill constant (Ka) is defined and values derived. A rule-of-thumb method for the optimized design of cooling towers is presented. The rule-of-thumb design method provides information useful in power plant cycle optimization, including tower dimensions, water consumption rate, exit air temperature,more » power requirements and construction cost. In addition, a method for simulation of cooling tower performance at various operating conditions is presented. This information is also useful in power plant cycle evaluation. Using the information presented, it will be possible to incorporate wet cooling tower design and simulation into a procedure to evaluate and optimize power plant cycles.« less

Fixation light hue bias revisited: implications for using adaptive optics to study color vision.

PubMed

Hofer, H J; Blaschke, J; Patolia, J; Koenig, D E

2012-03-01

Current vision science adaptive optics systems use near infrared wavefront sensor 'beacons' that appear as red spots in the visual field. Colored fixation targets are known to influence the perceived color of macroscopic visual stimuli (Jameson, D., & Hurvich, L. M. (1967). Fixation-light bias: An unwanted by-product of fixation control. Vision Research, 7, 805-809.), suggesting that the wavefront sensor beacon may also influence perceived color for stimuli displayed with adaptive optics. Despite its importance for proper interpretation of adaptive optics experiments on the fine scale interaction of the retinal mosaic and spatial and color vision, this potential bias has not yet been quantified or addressed. Here we measure the impact of the wavefront sensor beacon on color appearance for dim, monochromatic point sources in five subjects. The presence of the beacon altered color reports both when used as a fixation target as well as when displaced in the visual field with a chromatically neutral fixation target. This influence must be taken into account when interpreting previous experiments and new methods of adaptive correction should be used in future experiments using adaptive optics to study color. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Analysis of tension-distraction state in the shin bones fractures in conditions of external fixation with application of apparatuses with different spatially oriented supports].

PubMed

Hutsuliak, V I

2014-09-01

In Autodesk Inventor 11 program, using method of end-capping elements, a three- dimensional computeric modelling of biomechanical systems of two models was conducted: I - "tibia - Ilizarov's apparatus with concentric location of supports"; II - "tibia - Ilizarov's apparatus with excentric location of supports". The loading, which was applied towards distal fragment in 6 standard degrees of freedom, was modelled for studying of the fixation rigidity of tibial fragments in these systems. Determination of the loading value in various directions, in which the fragment have had shifted by 1 mm, have constituted the main task of the investigation. In a model II a rigidity of the fragments fixation, in comparison with such in a model I, is bigger by 631.43% - while applying a compression loading, by 8.35 - 31.75% - the transversal one and by 19.72% - the rotation loading. While choosing the method of transosteal osteosynthesis of the shin bones the advantage, have the apparatuses with excentric location of supports, what secures the enhanced rigidity of the fragments fixation in comparison with such in apparatuses with concentric location of supports. Although, even in excentric location of supports in the apparatus the fixation rigidity is insufficient for early full loading of the traumatized extremity while walking. It is necessary to elaborate such apparatus, the form of which may be adopted toanatomic configuration of segment.

Information-theoretic model comparison unifies saliency metrics

PubMed Central

Kümmerer, Matthias; Wallis, Thomas S. A.; Bethge, Matthias

2015-01-01

Learning the properties of an image associated with human gaze placement is important both for understanding how biological systems explore the environment and for computer vision applications. There is a large literature on quantitative eye movement models that seeks to predict fixations from images (sometimes termed “saliency” prediction). A major problem known to the field is that existing model comparison metrics give inconsistent results, causing confusion. We argue that the primary reason for these inconsistencies is because different metrics and models use different definitions of what a “saliency map” entails. For example, some metrics expect a model to account for image-independent central fixation bias whereas others will penalize a model that does. Here we bring saliency evaluation into the domain of information by framing fixation prediction models probabilistically and calculating information gain. We jointly optimize the scale, the center bias, and spatial blurring of all models within this framework. Evaluating existing metrics on these rephrased models produces almost perfect agreement in model rankings across the metrics. Model performance is separated from center bias and spatial blurring, avoiding the confounding of these factors in model comparison. We additionally provide a method to show where and how models fail to capture information in the fixations on the pixel level. These methods are readily extended to spatiotemporal models of fixation scanpaths, and we provide a software package to facilitate their use. PMID:26655340

Finite element analysis of intramedullary nailing and double locking plate for treating extra-articular proximal tibial fractures.

PubMed

Chen, Fancheng; Huang, Xiaowei; Ya, Yingsun; Ma, Fenfen; Qian, Zhi; Shi, Jifei; Guo, Shuolei; Yu, Baoqing

2018-01-16

Proximal tibia fractures are one of the most familiar fractures. Surgical approaches are usually needed for anatomical reduction. However, no single treatment method has been widely established as the standard care. Our present study aims to compare the stress and stability of intramedullary nails (IMN) fixation and double locking plate (DLP) fixation in the treatment of extra-articular proximal tibial fractures. A three-dimensional (3D) finite element model of the extra-articular proximal tibial fracture, whose 2-cm bone gap began 7 cm from the tibial plateau articular surface, was created fixed by different fixation implants. The axial compressive load on an adult knee during single-limb stance was imitated by an axial force of 2500 N with a distribution of 60% to the medial compartment, while the distal end was fixed effectively. The equivalent von Mises stress and displacement of the model was used as the output measures for analysis. The maximal equivalent von Mises stress value of the system in the IMN model was 293.23 MPa, which was higher comparing against that in the DLP fixation model (147.04 MPa). And the mean stress of the model in the IMN model (9.25 MPa) was higher than that of the DLP fixation system in terms of equivalent von Mises stress (EVMS) (P < 0.0001). The maximal value of displacement (sum) in the IMN system was 8.82 mm, which was lower than that in the DLP fixation system (9.48 mm). This study demonstrated that the stability provided by the locking plate fixation system was superior to the intramedullary nails fixation system and served as an alternative fixation for the extra-articular proximal tibial fractures of young patients.

Treatment of Unicameral Bone Cysts of the Proximal Femur With Internal Fixation Lessens the Risk of Additional Surgery.

PubMed

Wilke, Benjamin; Houdek, Matthew; Rao, Rameshwar R; Caird, Michelle S; Larson, A Noelle; Milbrandt, Todd

2017-09-01

Little data exist to guide the treatment of unicameral bone cysts in the proximal femur. Methods of treatment include corticosteroid injections, curettage and bone grafting, and internal fixation. The authors completed a multi-institutional, retrospective review to evaluate their experience with proximal femoral unicameral bone cysts. They posed the following questions: (1) Does internal fixation reduce the risk of further procedures for the treatment of a unicameral bone cyst? (2) Is radiographic healing faster with internal fixation? Following institutional review board approval, the authors conducted a retrospective review of 36 patients treated for a unicameral bone cyst of the proximal femur at their institutions between 1974 and 2014. Medical records and radiographs were reviewed to identify patient demographics and treatment outcomes. Tumor locations included femoral neck (n=13), intertrochanteric (n=16), and subtrochanteric (n=7). Initial treatment included steroid injection (n=2), curettage and bone grafting (n=9), and internal fixation with curettage and bone grafting (n=25). Mean time was 9 months to radiographic healing and 15 months to return to full activity. The number of patients requiring additional surgeries was increased among those who did not undergo internal fixation. There was no difference in time to radiographic healing. However, time to return to normal activities was reduced if patients had received internal fixation. A significant reduction in additional procedures was observed when patients had been treated with internal fixation. Although this did not influence time to radiographic healing, patients did return to normal activities sooner. Internal fixation should be considered in the treatment of proximal femoral unicameral bone cysts. [Orthopedics. 2017; 40(5):e862-e867.]. Copyright 2017, SLACK Incorporated.

Intramedullary Percutaneous Fixation of Extra-Articular Proximal and Middle Phalanx Fractures.

PubMed

Jovanovic, Nebojsa; Aldlyami, Ehab; Saraj, Basem; Fm Seidam, Mohamed; Badawi, Hamed; Shaat, Ahmed; Alawadi, Khalid; Dodakundi, Chaitanya

2018-06-01

Multiple methods have been described for treating unstable proximal and middle phalangeal fractures. Irrespective of using an open or closed technique of fixation, stiffness and extensor lag at the proximal/distal interphalangeal joint almost always occur. This issue can be avoided by allowing the patients to mobilize the fingers out of plaster or splint as early as possible from the day of surgery. We describe a technique of intramedullary percutaneous fixation of extra-articular proximal and middle phalanx fractures allowing immediate mobilization of fingers, concurrent stabilization with progressive healing and thus preventing such complications.

Cortical bone trajectory screw fixation versus traditional pedicle screw fixation for 2-level posterior lumbar interbody fusion: comparison of surgical outcomes for 2-level degenerative lumbar spondylolisthesis.

PubMed

Sakaura, Hironobu; Miwa, Toshitada; Yamashita, Tomoya; Kuroda, Yusuke; Ohwada, Tetsuo

2018-01-01

OBJECTIVE The cortical bone trajectory (CBT) screw technique is a new nontraditional pedicle screw (PS) insertion method. However, the biomechanical behavior of multilevel CBT screw/rod fixation remains unclear, and surgical outcomes in patients after 2-level posterior lumbar interbody fusion (PLIF) using CBT screw fixation have not been reported. Thus, the purposes of this study were to examine the clinical and radiological outcomes after 2-level PLIF using CBT screw fixation for 2-level degenerative lumbar spondylolisthesis (DS) and to compare these outcomes with those after 2-level PLIF using traditional PS fixation. METHODS The study included 22 consecutively treated patients who underwent 2-level PLIF with CBT screw fixation for 2-level DS (CBT group, mean follow-up 39 months) and a historical control group of 20 consecutively treated patients who underwent 2-level PLIF using traditional PS fixation for 2-level DS (PS group, mean follow-up 35 months). Clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) scoring system. Bony union was assessed by dynamic plain radiographs and CT images. Surgery-related complications, including symptomatic adjacent-segment disease (ASD), were examined. RESULTS The mean operative duration and intraoperative blood loss were 192 minutes and 495 ml in the CBT group and 218 minutes and 612 ml in the PS group, respectively (p < 0.05 and p > 0.05, respectively). The mean JOA score improved significantly from 12.3 points before surgery to 21.1 points (mean recovery rate 54.4%) at the latest follow-up in the CBT group and from 12.8 points before surgery to 20.4 points (mean recovery rate 51.8%) at the latest follow-up in the PS group (p > 0.05). Solid bony union was achieved at 90.9% of segments in the CBT group and 95.0% of segments in the PS group (p > 0.05). Symptomatic ASD developed in 2 patients in the CBT group (9.1%) and 4 patients in the PS group (20.0%, p > 0.05). CONCLUSIONS Two-level PLIF with CBT screw fixation for 2-level DS could be less invasive and result in improvement of clinical symptoms equal to those of 2-level PLIF using traditional PS fixation. The incidence of symptomatic ASD and the rate of bony union were lower in the CBT group than in the PS group, although these differences were not significant.

Biomedical analysis of formalin-fixed, paraffin-embedded tissue samples: The Holy Grail for molecular diagnostics.

PubMed

Donczo, Boglarka; Guttman, Andras

2018-06-05

More than a century ago in 1893, a revolutionary idea about fixing biological tissue specimens was introduced by Ferdinand Blum, a German physician. Since then, a plethora of fixation methods have been investigated and used. Formalin fixation with paraffin embedment became the most widely used types of fixation and preservation method, due to its proper architectural conservation of tissue structures and cellular shape. The huge collection of formalin-fixed, paraffin-embedded (FFPE) sample archives worldwide holds a large amount of unearthed information about diseases that could be the Holy Grail in contemporary biomarker research utilizing analytical omics based molecular diagnostics. The aim of this review is to critically evaluate the omics options for FFPE tissue sample analysis in the molecular diagnostics field. Copyright © 2018. Published by Elsevier B.V.

Operative Cost Comparison: Plating Versus Intramedullary Fixation for Clavicle Fractures.

PubMed

Hanselman, Andrew E; Murphy, Timothy R; Bal, George K; McDonough, E Barry

2016-09-01

Although clavicle fractures often heal well with nonoperative management, current literature has shown improved outcomes with operative intervention for specific fracture patterns in specific patient types. The 2 most common methods of midshaft clavicle fracture fixation are intramedullary and plate devices. Through retrospective analysis, this study performed a direct cost comparison of these 2 types of fixation at a single institution over a 5-year period. Outcome measures included operative costs for initial surgery and any hardware removal surgeries. This study reviewed 154 patients (157 fractures), and of these, 99 had intramedullary fixation and 58 had plate fixation. A total of 80% (79 of 99) of intramedullary devices and 3% (2 of 58) of plates were removed. Average cost for initial intramedullary placement was $2955 (US dollars) less than that for initial plate placement (P<.001); average cost for removal was $1874 less than that for plate removal surgery (P=.2). Average total cost for all intramedullary surgeries was $1392 less than the average cost for all plating surgeries (P<.001). Average cost for all intramedullary surgeries requiring plate placement and removal was $653 less than the average cost for all plating surgeries that involved only placement (P=.04). Intramedullary fixation of clavicle fractures resulted in a statistically significant cost reduction compared with plate fixation, despite the incidence of more frequent removal surgeries. [Orthopedics.2016; 39(5):e877-e882.]. Copyright 2016, SLACK Incorporated.

Fixation of Hydroxyapatite-Coated Revision Implants Is Improved by the Surgical Technique of Cracking the Sclerotic Bone Rim

PubMed Central

Elmengaard, Brian; Bechtold, Joan E.; Chen, Xinqian; Søballe, Kjeld

2013-01-01

Revision joint replacement has poorer outcomes that have been associated with poorer mechanical fixation. We investigate a new bone-sparing surgical technique that locally cracks the sclerotic bone rim formed during aseptic loosening. We inserted 16 hydroxyapatite-coated implants bilaterally in the distal femur of eight dogs, using a controlled weight-bearing experimental model that replicates important features of a typical revision setting. At 8 weeks, a control revision procedure and a crack revision procedure were performed on contralateral implants. The crack procedure used a splined tool to perform a systematic local perforation of the sclerotic bone rim of the revision cavity. After 4 weeks, the hydroxyapatite-coated implants were evaluated for mechanical fixation by a push-out test and for tissue distribution by histomorphometry. The cracking revision procedure resulted in significantly improved mechanical fixation, significantly more bone ongrowth and bone volume in the gap, and reduced fibrous tissue compared to the control revision procedure. The study demonstrates that the sclerotic bone rim prevents bone ingrowth and promotes fixation by fibrous tissue. The effect of the cracking technique may be due to improved access to the vascular compartment of the bone. The cracking technique is a simple surgical method that potentially can improve the fixation of revision implants in sclerotic regions important for obtaining the fixation critical for overall implant stability. PMID:19148940

Partly versus Completely out of Your Mind: Effects of Incubation and Distraction on Resolving Fixation

ERIC Educational Resources Information Center

Kohn, Nicholas; Smith, Steven M.

2009-01-01

Incubation has long been proposed as a mechanism in creative problem solving (Wallas, 1926). A new trial-by-trial method for observing incubation effects was used to compare the forgetting fixation hypothesis with the conscious work hypothesis. Two experiments examined the effects of incubation on initially unsolved Remote Associates Test (RAT)…

Design Fixation and Cooperative Learning in Elementary Engineering Design Project: A Case Study

ERIC Educational Resources Information Center

Luo, Yi

2015-01-01

This paper presents a case study examining 3rd, 4th and 5th graders' design fixation and cooperative learning in an engineering design project. A mixed methods instrument, the Cooperative Learning Observation Protocol (CLOP), was adapted to record frequency and class observation on cooperative learning engagement through detailed field notes.…

Biological Nitrogen Fixation In Tropical Dry Forests Of Costa Rica

NASA Astrophysics Data System (ADS)

Gei, M. G.; Powers, J. S.

2012-12-01

Evidence suggests that tropical dry forests (TDF) are not nitrogen (N) deficient. This evidence includes: high losses of gaseous nitrogen during the rainy season, high ecosystem soil N stocks and high N concentrations in leaves and litterfall. Its been commonly hypothesized that biological nitrogen fixation is responsible for the high availability of N in tropical soils. However, the magnitude of this flux has rarely if ever been measured in tropical dry forests. Because of the high cost of fixing N and the ubiquity of N fixing legume trees in the TDF, at the individual tree level symbiotic fixation should be a strategy down-regulated by the plant. Our main goal was to determine the rates of and controls over symbiotic N fixation. We hypothesized that legume tree species employ a facultative strategy of nitrogen fixation and that this process responds to changes in light availability, soil moisture and nutrient supply. We tested this hypothesis both on naturally established trees in a forest and under controlled conditions in a shade house by estimating the quantities of N fixed annually using the 15N natural abundance method, counting nodules, and quantifying (field) or manipulating (shade house) the variation in important environmental variables (soil nutrients, soil moisture, and light). We found that in both in our shade house experiment and in the forest, nodulation varied among different legume species. For both settings, the 15N natural abundance approach successfully detected differences in nitrogen fixation among species. The legume species that we studied were able to regulate fixation depending on the environmental conditions. They showed to have different strategies of nitrogen fixation that follow a gradient of facultative to obligate fixation. Our data suggest that there exists a continuum of nitrogen fixation strategies among species. Any efforts to define tropical legume trees as a functional group need to incorporate this variation.

An improved methodology for investigating the parameters influencing migration resistance of abdominal aortic stent-grafts.

PubMed

Corbett, Timothy J; Callanan, Anthony; O'Donnell, Michael R; McGloughlin, Tim M

2010-02-01

To develop an improved methodology for investigating the parameters influencing stent-graft migration, with particular focus on the limitations of existing methods. A physiological silicone rubber abdominal aortic aneurysm (AAA) model for fixation studies was manufactured based on an idealized AAA geometry: the model had a 24-mm neck, a 50-mm aneurysm, 12-mm-diameter legs, a 60 degrees bifurcation angle, and 2-mm-thick walls. The models were authenticated in neck fixation experiments. The displacement force required to migrate stent-grafts in physiological pulsatile flow was tested dynamically in water at 37 degrees C. A commercially available longitudinally rigid stent-graft (AneuRx) and a homemade device with little longitudinal rigidity were studied in a number of different configurations to investigate the effect of neck fixation length and systolic pressure on displacement force. The AneuRx (6.95+/-0.49 to 8.52+/-0.5 N) performed significantly better than the homemade device (2.57+/-0.11 to 4.62+/-0.25 N) in pulsatile flow. The opposite was true in the neck fixation tests because the longitudinal stiffness of the AneuRx was not accounted for. Increasing pressure or decreasing fixation length compromised the fixation of the homemade device. This relationship was not as clear for the AneuRx because decreasing proximal fixation resulted in an increase in iliac fixation, which could assist fixation in this device. Assessing the migration resistance of stent-grafts based solely on proximal fixation discriminates against devices that are longitudinally stiff. Current in vivo models may give inaccurate displacement forces due to the high degree of oversizing in these studies. A novel in vitro approach, accounting for longitudinal rigidity and realistic graft oversizing, was developed to determine the resistance of aortic stent-grafts to migration in the period immediately after device implantation.

A cost/utility analysis of open reduction and internal fixation versus cast immobilization for acute nondisplaced mid-waist scaphoid fractures.

PubMed

Davis, Erika N; Chung, Kevin C; Kotsis, Sandra V; Lau, Frank H; Vijan, Sandeep

2006-04-01

Open reduction and internal fixation and cast immobilization are both acceptable treatment options for nondisplaced waist fractures of the scaphoid. The authors conducted a cost/utility analysis to weigh open reduction and internal fixation against cast immobilization in the treatment of acute nondisplaced mid-waist scaphoid fractures. The authors used a decision-analytic model to calculate the outcomes and costs of open reduction and internal fixation and cast immobilization, assuming the societal perspective. Utilities were assessed from 50 randomly selected medical students using the time trade-off method. Outcome probabilities taken from the literature were factored into the calculation of quality-adjusted life-years associated with each treatment. The authors estimated medical costs using Medicare reimbursement rates, and costs of lost productivity were estimated by average wages obtained from the U.S. Bureau of Labor Statistics. Open reduction and internal fixation offers greater quality-adjusted life-years compared with casting, with an increase ranging from 0.21 quality-adjusted life-years for the 25- to 34-year age group to 0.04 quality-adjusted life-years for the > or =65-year age group. Open reduction and internal fixation is less costly than casting ($7940 versus $13,851 per patient) because of a longer period of lost productivity with casting. Open reduction and internal fixation is therefore the dominant strategy. When considering only direct costs, the incremental cost/utility ratio for open reduction and internal fixation ranges from $5438 per quality-adjusted life-year for the 25- to 34-year age group to $11,420 for the 55- to 64-year age group, and $29,850 for the > or =65-year age group. Compared with casting, open reduction and internal fixation is cost saving from the societal perspective ($5911 less per patient). When considering only direct costs, open reduction and internal fixation is cost-effective relative to other widely accepted interventions.

Wet Snow Mapping in Southern Ontario with Sentinel-1A Observations

NASA Astrophysics Data System (ADS)

Chen, H.; Kelly, R. E. J.

2017-12-01

Wet snow is defined as snow with liquid water present in an ice-water mix. It is can be an indicator for the onset of the snowmelt period. Knowledge about the extent of wet snow area can be of great importance for the monitoring of seasonal snowmelt runoff with climate-induced changes in snowmelt duration having implications for operational hydrological and ecological applications. Spaceborne microwave remote sensing has been used to observe seasonal snow under all-weather conditions. Active microwave observations of snow at C-band are sensitive to wet snow due to the high dielectric contrast with non-wet snow surfaces and synthetic aperture radar (SAR) is now openly available to identify and map the wet snow areas globally at relatively fine spatial resolutions ( 100m). In this study, a semi-automated workflow is developed from the change detection method of Nagler et al. (2016) using multi-temporal Sentinel-1A (S1A) dual-polarization observations of Southern Ontario. Weather station data and visible-infrared satellite observations are used to refine the wet snow area estimates. Wet snow information from National Operational Hydrologic Remote Sensing Center (NOHRSC) is used to compare with the S1A estimates. A time series of wet snow maps shows the variations in backscatter from wet snow on a pixel basis. Different land cover types in Southern Ontario are assessed with respect to their impacts on wet snow estimates. While forests and complex land surfaces can impact the ability to map wet snow, the approach taken is robust and illustrates the strong sensitivity of the approach to wet snow backscattering characteristics. The results indicate the feasibility of the change detection method on non-mountainous large areas and address the usefulness of Sentinel-1A data for wet snow mapping.

Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

PubMed

Galos, David; Taylor, Benjamin; McLaurin, Toni

2017-01-01

Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

A practical tissue sampling method using ordinary paper for molecular detection of infectious bursal disease virus RNA by RT-PCR.

PubMed

Maw, Min Thein; Yamaguchi, Tsuyoshi; Kasanga, Christopher J; Terasaki, Kaori; Fukushi, Hideto

2006-12-01

A practical sampling method for bursal tissue using ordinary paper for molecular diagnosis of infectious bursal disease (IBD) was established. IBD virus-infected bursa was directly smeared on chromatography paper, filter paper, or stationery copy paper and was then fixed with absolute ethanol, Tris-HCl-saturated phenol, or phenol:chloroform:isoamyl alcohol (25:24:1). Flinders Technology Associates (FTA) card, which is designed for the collection of biological samples for molecular detection, was also used. After storage at 37 C for up to 30 days, total RNA directly extracted from the tissue fixed on the papers and FTA card were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of IBD virus (IBDV) RNA. In addition, the ability of each chemical used in the fixation and the FTA card to inactivate IBDV was evaluated. Regardless of the paper quality, storage period, and fixation method, IBDV RNA was consistently detected in all of the samples. IBDV in the bursal tissue was inactivated with phenol but not with ethanol or the unknown chemicals in FTA card. These results show that ordinary papers sustain the viral RNA, as does FTA card, but phenol fixation is superior to FTA card in inactivating IBDV. The new sampling method using ordinary paper with phenol fixation is safe, inexpensive, simple, and easy, and is thus suitable for conducting a global survey of IBD even where laboratory resources are limited. This practical method should contribute to the control of IBD worldwide.

Osteotomy and fracture fixation in children and teenagers.

PubMed

de Billy, B; Gindraux, F; Langlais, J

2014-02-01

Significant changes have occurred recently in fixation methods following fracture or osteotomy in children and teenagers. Children have benefited the most from these advances. A child's growth is anatomically and physiologically ensured by the growth plate and periosteum. The need to keep the periosteum intact during trauma cases has led to the introduction of flexible intramedullary nailing. We will review the basic principles of this safe, universally adopted technique, and also describe available material, length and diameter options. The problems and the limitations of this method will be discussed extensively. In orthopedics, the desire to preserve the periosteum has led to the use of locking compression plates. Because of their low profile and high stability, they allow the micromovements essential for bone union. These new methods reduce the immobilization period and allow autonomy to be regained more quickly, which is especially important in children with neurological impairment. The need to preserve the growth plate, which is well known in pediatric surgery, is reviewed with the goal of summarizing current experimental data on standard fracture and osteotomy fixation methods. Adjustable block stop wires provide better control over compression. These provide an alternate means of fixation between K-wires and screws (now cannulated) and have contributed to the development of minimally invasive surgical techniques. The aim of this lecture is to provide a rationale for the distinct technical features of pediatric surgery, while emphasizing the close relationship between the physiology of growth, bone healing and technical advances. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Weigners fixative-an alternative to formalin fixation for histology with improved preservation of nucleic acids.

PubMed

Klopfleisch, R; von Deetzen, M; Weiss, A Th; Weigner, J; Weigner, F; Plendl, J; Gruber, A D

2013-01-01

Formalin fixation and paraffin embedding (FFPE) is the standard method for tissue storage in histopathology. However, FFPE has disadvantages in terms of user health, environment, and nucleic acid integrity. Weigners fixative has been suggested as an alternative for embalming cadavers in human and veterinary anatomy. The present study tested the applicability of Weigners for histology and immunohistochemistry and the preservation of nucleic acids. To this end, a set of organs was fixed for 2 days and up to 6 months in Weigners (WFPE) or formalin. WFPE tissues from the skin, brain, lymphatic tissues, liver, and muscle had good morphologic preservation, comparable to formalin fixation. The quality of kidney and lung samples was inferior to FFPE material due to less accentuated nuclear staining and retention of proteinaceous interstitial fluids. Azan, Turnbull blue, toluidin, and immunohistochemical stainings for CD79a, cytokeratin, vimentin, and von Willebrand factor led to comparable results with both fixates. Of note, immunohistochemical detection of CD3 was possible after 6 months in WFPE but not in FFPE tissues. mRNA, miRNA, and DNA from WFPE tissues had superior quality and allowed for amplification of miRNA, 400-bp-long mRNA, and 1000-bp-long DNA fragments after 6 months of fixation in WFPE. In summary, Weigners fixative is a nonhazardous alternative to formalin, which provides a good morphologic preservation of most organs, a similar sensitivity for protein detection, and a superior preservation of nucleic acids. Weigners may therefore be a promising alternative to cryopreservation and may be embraced by people affected by formalin allergies.

External versus internal fixation for bicondylar tibial plateau fractures: systematic review and meta-analysis.

PubMed

Metcalfe, David; Hickson, Craig J; McKee, Lesley; Griffin, Xavier L

2015-12-01

It is uncertain whether external fixation or open reduction internal fixation (ORIF) is optimal for patients with bicondylar tibial plateau fractures. A systematic review using Ovid MEDLINE, Embase Classic, Embase, AMED, the Cochrane Library, Open Grey, Orthopaedic Proceedings, WHO International Clinical Trials Registry Platform, Current Controlled Trials, US National Institute for Health Trials Registry, and the Cochrane Central Register of Controlled Trials. The search was conducted on 3rd October 2014 and no language limits were applied. Inclusion criteria were all clinical study designs comparing external fixation with open reduction internal fixation of bicondylar tibial plateau fractures. Studies of only one treatment modality were excluded, as were those that included unicondylar tibial plateau fractures. Treatment effects from studies reporting dichotomous outcomes were summarised using odds ratios. Continuous outcomes were converted to standardized mean differences to assess the treatment effect, and inverse variance methods used to combine data. A fixed effect model was used for meta-analyses. Patients undergoing external fixation were more likely to have returned to preinjury activities by six and twelve months (P = 0.030) but not at 24 months follow-up. However, external fixation was complicated by a greater number of infections (OR 2.59, 95 % CI 1.25-5.36, P = 0.01). There were no statistically significant differences in the rates of deep infection, venous thromboembolism, compartment syndrome, or need for re-operation between the two groups. Although external fixation and ORIF are associated with different complication profiles, both are acceptable strategies for managing bicondylar tibial plateau fractures.

Changes in the syndesmotic reduction after syndesmotic screw fixation for ankle malleolar fractures: One-year longitudinal evaluations using computer tomography.

PubMed

Endo, Jun; Yamaguchi, Satoshi; Saito, Masahiko; Morikawa, Tsuguo; Akagi, Ryuichiro; Sasho, Takahisa

2016-10-01

To evaluate time-dependent changes in the syndesmotic reduction after syndesmotic screw fixation and one year after screw removal for ankle malleolar fractures, and to assess whether the incidence of syndesmotic malreduction changes depending on the measurement method. We assessed twenty patients who underwent syndesmotic screw fixation for ankle fractures. The syndesmotic screws were removed after six weeks of the fracture surgery. Syndesmotic reduction was assessed within two weeks of the fracture surgery and one year after the screw removal using the axial computer tomographic images. Side-to-side differences in the anterior and posterior tibiofibular distances, anteroposterior fibular translation, and fibular rotation were measured. The mean anterior tibiofibular distance was 0.7mm after syndesmotic fixation. It increased to 1.9mm at one year after screw removal (p=0.002). After syndesmotic fixation, four ankles had malreduction of the anterior tibiofibular distance, including three ankles with widening and one with overtightening. At one year, eight ankles had malreduction, all of whom had widening. The other measurement values did not change over time (0.1mm vs. 0.6mm for the posterior tibiofibular distance, 0.2mm vs. 0.3mm for the anteroposterior fibular translation, and 0.7° vs. 0° for the fibular rotation). The incidences of malreduction were significantly different depending on the definition of malreduction, ranging from 10% to 50% after syndesmotic fixation (p=0.01) and from 20% to 60% at one year after screw removal (p=0.02). The anterior tibiofibular distance widened after one year of syndesmotic screw removal. The incidence of malreduction varied depending on the measurement method. Copyright © 2016. Published by Elsevier Ltd.

Dynamic RSA for the evaluation of inducible micromotion of Oxford UKA during step-up and step-down motion.

PubMed

Horsager, Kristian; Kaptein, Bart L; Rømer, Lone; Jørgensen, Peter B; Stilling, Maiken

2017-06-01

Background and purpose - Implant inducible micromotions have been suggested to reflect the quality of the fixation interface. We investigated the usability of dynamic RSA for evaluation of inducible micromotions of the Oxford Unicompartmental Knee Arthroplasty (UKA) tibial component, and evaluated factors that have been suggested to compromise the fixation, such as fixation method, component alignment, and radiolucent lines (RLLs). Patients and methods - 15 patients (12 men) with a mean age of 69 (55-86) years, with an Oxford UKA (7 cemented), were studied after a mean time in situ of 4.4 (3.6-5.1) years. 4 had tibial RLLs. Each patient was recorded with dynamic RSA (10 frames/second) during a step-up/step-down motion. Inducible micromotions were calculated for the tibial component with respect to the tibia bone. Postoperative component alignment was measured with model-based RSA and RLLs were measured on screened radiographs. Results - All tibial components showed inducible micromotions as a function of the step-cycle motion with a mean subsidence of up to -0.06 mm (95% CI: -0.10 to -0.03). Tibial component inducible micromotions were similar for cemented fixation and cementless fixation. Patients with tibial RLLs had 0.5° (95% CI: 0.18-0.81) greater inducible medio-lateral tilt of the tibial component. There was a correlation between postoperative posterior slope of the tibial plateau and inducible anterior-posterior tilt. Interpretation - All patients had inducible micromotions of the tibial component during step-cycle motion. RLLs and a high posterior slope increased the magnitude of inducible micromotions. This suggests that dynamic RSA is a valuable clinical tool for the evaluation of functional implant fixation.

Clinical Outcomes of Posterior C1 and C2 Screw-Rod Fixation for Atlantoaxial Instability.

PubMed

Işik, Hasan Serdar; Sandal, Evren; Çağli, Sedat

2017-06-14

In this study, we aimed at sharing our experiences and contributing to the literature by making a retrospective analysis of the patients we operated with screw-rod system for atlantoaxial instability in our clinic. Archive files of adult patients, who were operated for posterior C1-C2 stabilization with screw and rod in our clinic between January 2006 and January 2016, were analyzed. 28 patients, who had pre and post-operative images, follow-up forms and who were followed for at least one year, were analyzed. Preoperative clinical and radiological records, preoperative observations, postoperative complications, and clinical responses were evaluated. The average age of 28 patients (F:13 M:19) was 44.7 (21-73). Fixation was performed with C1-C2 screw-rod system on the basis of the following diagnoses; type 2 odontoid fracture (16), basilar invagination (5), C1-C2 instability (5), and atlantoaxial subluxation secondary to rheumatoid arthritis (2). Lateral mass screws were inserted at C1 segment. C2 screws inserted were bilateral pedicle in 12 cases, bilateral pars in 4, bilateral laminar in 8 and one side pars, one side laminar in 4 cases. There was no screw malposition. Neither implant failure nor recurrent instability was observed during follow-up. Significant clinical improvement was reported according to the assessments done with JOA and VAS scores. C1-C2 screw fixation is regarded as a more successful and safe method than other fixation methods in surgical treatment of atlantoaxial instability considering complications, success in reduction, fusion and fixation strength. C2 laminar screw technique is as successful as the other alternatives in fixation and fusion.

Comparison of fixation and processing methods for hairless guinea pig skin following sulfur mustard exposure. (Reannouncement with new availability information)

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

Bryant, M.A.; Braue Jr, E.H.

1992-12-31

Ten anesthetized hairless guinea pigs Crl:IAF(HA)BR were exposed to 10 pi of neat sulfur mustard (HD) in a vapor cup on their skin for 7 min. At 24 h postexposure, the guinea pigs were euthanatized and skin sections taken for histologic evaluation. The skin was fixed using either 10% neutral buffered formalin (NBF), McDowell Trump fixative (4CF-IG), Zenker`s formol-saline (Helly`s fluid), or Zenker`s fluid. Fixed skin sections were cut in half: one half was embedded in paraffin and the other half in plastic (glycol methacrylate). Paraffin-embedded tissue was stained with hematoxylin and eosin; plastic-embedded tissue was stained with Lee`s methylenemore » blue basic fuchsin. Skin was also frozen unfixed, sectioned by cryostat, and stained with pinacyanole. HD-exposed skin was evaluated histologically for the presence of epidermal and follicular necrosis, microblister formation, epidermitis, and intracellular edema to determine the optimal fixation and embedding method for lesion preservation. The percentage of histologic sections with lesions varied little between fixatives and was similar for both paraffin and plastic embedding material. Plastic-embedded sections were thinner, allowing better histologic evaluation, but were more difficult to stain. Plastic embedding material did not infiltrate tissue fixed in Zenker`s fluid or Zenker`s formol-saline. Frozen tissue sections were prepared in the least processing time and lesion preservation was comparable to fixed tissue. It was concluded that standard histologic processing using formalin fixation and paraffin embedding is adequate for routine histopathological evaluation of HD skin lesions in the hairless guinea pig.... Sulfur mustard, Vesicating agents, Pathology, Hairless guinea pig model, Fixation.« less

Reliability and Validity of Isometric Knee Extensor Strength Test With Hand-Held Dynamometer Depending on Its Fixation: A Pilot Study

PubMed Central

Kim, Won Kuel; Seo, Kyung Mook; Kang, Si Hyun

2014-01-01

Objective To determine the reliability and validity of hand-held dynamometer (HHD) depending on its fixation in measuring isometric knee extensor strength by comparing the results with an isokinetic dynamometer. Methods Twenty-seven healthy female volunteers participated in this study. The subjects were tested in seated and supine position using three measurement methods: isometric knee extension by isokinetic dynamometer, non-fixed HHD, and fixed HHD. During the measurement, the knee joints of subjects were fixed at a 35° angle from the extended position. The fixed HHD measurement was conducted with the HHD fixed to distal tibia with a Velcro strap; non-fixed HHD was performed with a hand-held method without Velcro fixation. All the measurements were repeated three times and among them, the maximum values of peak torque were used for the analysis. Results The data from the fixed HHD method showed higher validity than the non-fixed method compared with the results of the isokinetic dynamometer. Pearson correlation coefficients (r) between fixed HHD and isokinetic dynamometer method were statistically significant (supine-right: r=0.806, p<0.05; seating-right: r=0.473, p<0.05; supine-left: r=0.524, p<0.05), whereas Pearson correlation coefficients between non-fixed dynamometer and isokinetic dynamometer methods were not statistically significant, except for the result of the supine position of the left leg (r=0.384, p<0.05). Both fixed and non-fixed HHD methods showed excellent inter-rater reliability. However, the fixed HHD method showed a higher reliability than the non-fixed HHD method by considering the intraclass correlation coefficient (fixed HHD, 0.952-0.984; non-fixed HHD, 0.940-0.963). Conclusion Fixation of HHD during measurement in the supine position increases the reliability and validity in measuring the quadriceps strength. PMID:24639931

The Cost-Effectiveness of Surgical Fixation of Distal Radial Fractures: A Computer Model-Based Evaluation of Three Operative Modalities.

PubMed

Rajan, Prashant V; Qudsi, Rameez A; Dyer, George S M; Losina, Elena

2018-02-07

There is no consensus on the optimal fixation method for patients who require a surgical procedure for distal radial fractures. We used cost-effectiveness analyses to determine which of 3 modalities offers the best value: closed reduction and percutaneous pinning, open reduction and internal fixation, or external fixation. We developed a Markov model that projected short-term and long-term health benefits and costs in patients undergoing a surgical procedure for a distal radial fracture. Simulations began at the patient age of 50 years and were run over the patient's lifetime. The analysis was conducted from health-care payer and societal perspectives. We estimated transition probabilities and quality-of-life values from the literature and determined costs from Medicare reimbursement schedules in 2016 U.S. dollars. Suboptimal postoperative outcomes were determined by rates of reduction loss (4% for closed reduction and percutaneous pinning, 1% for open reduction and internal fixation, and 11% for external fixation) and rates of orthopaedic complications. Procedural costs were $7,638 for closed reduction and percutaneous pinning, $10,170 for open reduction and internal fixation, and $9,886 for external fixation. Outputs were total costs and quality-adjusted life-years (QALYs), discounted at 3% per year. We considered willingness-to-pay thresholds of $50,000 and $100,000. We conducted deterministic and probabilistic sensitivity analyses to evaluate the impact of data uncertainty. From the health-care payer perspective, closed reduction and percutaneous pinning dominated (i.e., produced greater QALYs at lower costs than) open reduction and internal fixation and dominated external fixation. From the societal perspective, the incremental cost-effectiveness ratio for closed reduction and percutaneous pinning compared with open reduction and internal fixation was $21,058 per QALY and external fixation was dominated. In probabilistic sensitivity analysis, open reduction and internal fixation was cost-effective roughly 50% of the time compared with roughly 45% for closed reduction and percutaneous pinning. When considering data uncertainty, there is only a 5% to 10% difference in the frequency of probability combinations that find open reduction and internal fixation to be more cost-effective. The current degree of uncertainty in the data produces difficulty in distinguishing either strategy as being more cost-effective overall and thus it may be left to surgeon and patient shared decision-making. Economic Level III. See Instructions for Authors for a complete description of levels of evidence.

Reversing the effects of formalin fixation with citraconic anhydride and heat: a universal antigen retrieval method.

PubMed

Namimatsu, Shigeki; Ghazizadeh, Mohammad; Sugisaki, Yuichi

2005-01-01

Formalin is a commonly used fixative for tissue preservation in pathology laboratories. A major adverse effect of this fixative is the concealing of tissue antigens by protein cross-linking. To achieve a universal antigen retrieval method for immunohistochemistry under a constant condition, we developed a new method in which the effects of formalin fixation were reversed with citraconic anhydride (a reversible protein cross-linking agent) plus heating. Formalin-fixed, paraffin-embedded tissues from various organs were examined for immunohistochemical localization of a wide variety of antigens. Deparaffinized tissue sections were placed in an electric kitchen pot containing 0.05% citraconic anhydride solution, pH 7.4, and the pot was set at "keep warm" temperature mode of 98C for 45 min. This mode allowed heating the sections at a constant temperature. The sections were then washed in buffer solution and immunostained using a labeled streptavidin-biotin method using an automated stainer. In general, formalin-fixed tissues demonstrated specific immunostainings comparable to that in fresh frozen tissues and significantly more enhanced than after conventional antigen retrieval methods. In particular, even difficult-to-detect antigens such as CD4, cyclin D1, granzyme beta, bcl-6, CD25, and lambda chain revealed distinct immunostainings. Different classes of antigens such as cellular markers and receptors, as well as cytoplasmic and nuclear proteins, consistently produced enhanced reactions. This method provides efficient antigen retrieval for successful immunostaining of a wide variety of antigens under an optimized condition. It also allows standardization of immunohistochemistry for formalin-fixed tissues in pathology laboratories, eliminating inter-laboratory discrepancies in results for accurate clinical and research studies.

INNOVATIVE URBAN WET-WEATHER FLOW MANAGEMENT SYSTEMS

EPA Science Inventory

This report describes innovative methods to improve wet weather flow (WWF) management systems, that provide drainage services at the same time as decreasing stormwater pollutant discharges, for urban developments of the 21st century. Traditionally, wet-weather collection systems...

Knee arthrodesis using a customised modular intramedullary nail in failed infected total knee arthroplasty.

PubMed

Putman, S; Kern, G; Senneville, E; Beltrand, E; Migaud, H

2013-06-01

Knee arthrodesis is used to treat patients with failed infected total knee arthroplasty (TKA). Among fixation methods, intramedullary nailing increases the chances of bone union but may carry a risk of infection around the nail. This risk is not well understood, because available case-series studies were not confined to patients with knee infection. Infection recurrence rates after knee arthrodesis with intramedullary nailing used to treat failed infected TKA are similar to those seen with other fixation methods. We retrospectively reviewed 31 cases of knee arthrodesis with fixation by a modular intramedullary nail performed at a subspecialized center treating complex osteoarticular infections (CRIOAC). The antibiotic regimen was determined based on multidisciplinary discussions and microbiological studies of preoperative and intraoperative specimens. Mean follow-up was 50 ± 22 months (range, 28-90 months). Arthrodesis was performed in one stage (n=6) or two stages (n=25). Success was defined as presence, after a postoperative follow-up of at least 24 months, based on the following criteria: normal erythrocyte sedimentation rate and/or C-reactive protein, no wound inflammation or sinus tract, no revision surgery, and no antibiotic treatment. Bone union was not a criterion for a successful arthrodesis procedure. Removal of the fixation material was required in three patients and long-term palliative antibiotic therapy in three patients (fixation material in place with repeated positive specimens) for a total of six failures due to infection (6/31, 19.4%). None of the patients experienced mechanical failure (no breakage of the material and no fixation failure of the nails designed to allow osteointegration). The mean leg length discrepancy was 10 ± 10 mm (range, 5-34 mm) and the mean Oxford score was 41 ± 11 (range, 23-58). The 50-month rate of arthrodesis survival to revision surgery for nail removal was 77.8 ± 4% and the 50-month rate of arthrodesis survival without revision surgery for persistent infection was 74.6 ± 4.2%. The infection recurrence rate was higher than with other fixation methods but remained acceptable (19.4%). Use of a modular intramedullary nail prevented major leg-length discrepancies, which are often poorly accepted by the patients, and allowed immediate weight bearing despite the often severe bone loss. Level IV, retrospective cohort study. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Modified preauricular approach and rigid internal fixation for intracapsular condyle fracture of the mandible.

PubMed

He, Dongmei; Yang, Chi; Chen, Minjie; Bin, Jiang; Zhang, Xiaohu; Qiu, Yating

2010-07-01

This article reports a modified preauricular approach for intracapsular condyle fracture (ICF) of the mandible and evaluates the stability of various internal fixation methods in the temporomandibular joint (TMJ) division of the Shanghai Ninth People's Hospital. One hundred fifty-one patients with 208 ICFs diagnosed by panoramic radiograph and computed tomographic (CT) scan received open treatment in the TMJ division from 1999 to 2008. Their charts were reviewed. Classification of the fracture was based on coronal CT scan. Forty-three patients also underwent magnetic resonance imaging before the operation to check displacement of the disc. A modified preauricular approach was used for all patients. Various internal fixation methods from wire, to screw, to plate were evaluated for stability. There were 110 ICFs of type A fracture, 60 of type B fracture, 9 of type C fracture, 25 of type M fracture, and 4 fractures without displacement. A modified preauricular approach was used for open treatment, which can better expose and protect the TMJ and superficial temporal vessels. Wire and plate is the commonly used stable fixation method for type A, B, and M fractures, which accounted for 56.7% (101/178). Small fracture fragments were removed with disc repositioning for all type C fractures (n = 9) and some type B (n = 9) and M fractures (n = 5). Three type M fracture and 3 nondisplaced ICFs were treated closed. Eighty-nine patients with 115 ICFs had postoperative CT scan, which showed anatomic and nearly anatomic fracture reduction rates of 95.6%. Thirty-five patients with 44 ICFs had long-term follow-ups from 3 months to 5 years. Among them, 63.2% (n = 12/19) pediatric ICFs had continuous condyle growth after open reduction and rigid fixation; 92% adults had ICFs that healed well (n = 23/25). Postoperative complications were facial nerve injury (n = 3), TMJ clicking (n = 1), and condyle resorption that required plate removal (n = 4). A modified preauricular approach provides better exposure and protection of the TMJ and superficial temporal vessels. Wire and plate provides stable fixation for type A and some type B and M fractures. Open reduction and rigid fixation produce good results for adult patients. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Posterior internal fixation plus vertebral bone implantation under navigational aid for thoracolumbar fracture treatment

PubMed Central

ZHOU, WEI; KONG, WEIQING; ZHAO, BIZHEN; FU, YISHAN; ZHANG, TAO; XU, JIANGUANG

2013-01-01

The aim of this study was to investigate the method of posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid for the treatment of thoracolumbar fractures. The efficacy of the procedure was also measured. Between June 2005 and March 2011, posterior thoracolumbar vertebral pedicle screw reduction and fixation plus artificial bone implantation via the affected vertebral pedicle under navigational aid was used to treat 30 patients with thoracolumbar fractures, including 18 males and 12 females, ranging in age from 21 to 57 years. Compared with the values prior to surgery, intraspinal occupation, vertebral height ratio and Cobb angle at the follow-up were significantly improved. At the long-term follow-up, the postoperative Cobb angle loss was <1° and the anterior vertebral body height loss was <2 mm. Posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid may increase the accuracy and safety of surgery, and it is an ideal method of internal implantation. Bone implantation via the affected vertebral body may increase vertebral stability. PMID:23935737

Treatment of open tibial shaft fracture with soft tissue and bone defect caused by aircraft bomb--case report.

PubMed

Golubović, Zoran; Vidić, Goran; Trenkić, Srbobran; Vukasinović, Zoran; Lesić, Aleksandar; Stojiljković, Predrag; Stevanović, Goran; Golubović, Ivan; Visnjić, Aleksandar; Najman, Stevo

2010-01-01

Aircraft bombs can cause severe orthopaedic injuries. Tibia shaft fractures caused by aircraft bombs are mostly comminuted and followed by bone defects, which makes the healing process extremely difficult and prone to numerous complications. The goal of this paper is to present the method of treatment and the end results of treatment of a serious open tibial fracture with soft and bone tissue defects resulting from aircraft bomb shrapnel wounds. A 26-year-old patient presented with a tibial fracture as the result of a cluster bomb shrapnel wound. He was treated applying the method of external bone fixation done two days after wounding, as well as of early coverage of the lower leg soft tissue defects done on the tenth day after the external fixation of the fracture. The external fixator was removed after five months, whereas the treatment was continued by means of functional plaster cast for another two months. The final functional result was good. Radical wound debridement, external bone fixation of the fracture, and early reconstruction of any soft tissue and bone defects are the main elements of the treatment of serious fractures.

Randomized prospective study of olecranon fracture fixation: cable pin system versus tension band wiring.

PubMed

Liu, Q-H; Fu, Z-G; Zhou, J-L; Lu, T; Liu, T; Shan, L; Liu, Y; Bai, L

2012-01-01

This prospective, randomized study compared the effectiveness of the cable pin system (CPS) versus tension band wiring (TBW) for olecranon fracture fixation. Patients with acute transverse or slight oblique olecranon fractures were randomly divided into two groups: one fixed by CPS and the other by TBW. Clinical outcome data were collected and analysed following a mean duration of 21 months. The mean ± SD fracture healing time was significantly shorter in the CPS group (n = 30; 9.73 ± 2.02 weeks) compared with the TBW group (n = 32; 11.13 ± 2.21 weeks). One patient in the CPS group and seven patients in the TBW group experienced postoperative complications; this difference was statistically significant. The mean ± SD Mayo Elbow Performance Score in the CPS group was significantly higher (88.67 ± 6.42) than that in the TBW group (80.78 ± 11.99). Logistic regression analysis showed an association between fixation method and fracture healing time, complications and elbow function. Internal fixation by CPS is an effective method for olecranon fracture and is associated with a shorter healing time, fewer complications and better function than TBW.

Stress Fractures of Tibia Treated with Ilizarov External Fixator.

PubMed

Górski, Radosław; Żarek, Sławomir; Modzelewski, Piotr; Górski, Ryszard; Małdyk, Paweł

2016-08-30

Stress fractures are the result of cyclic loading of the bone, which gradually becomes damaged. Most often they are treated by rest or plaster cast and, in rare cases, by internal fixation. There is little published data on initial reposition followed by stabilization with the Ilizarov apparatus in such fractures. Six patients were treated with an external fixator according to the Ilizarov method for a stress fracture of the tibia between 2007 and 2015. Three patients were initially treated conservatively. Due to increasing tibial deformation, they were qualified for surgical treatment with external stabilization. In the other patients, surgery was the first-line treatment. All patients demonstrated risk factors for a stress fracture. After the surgery, they fully loaded the operated limb. No patient developed malunion, nonunion, infection or venous thrombosis. The average time from the first operation to the removal of the external fixator was 19 weeks. Radiographic and clinical outcomes were satisfactory in all patients. 1. The Ilizarov method allows for successful stabilization of stress fractures of the tibia. 2. It may be a good alternative to internal stabilization, especially in patients with multiple comorbidities which affect bone quality and may impair soft tissue healing.

Liquifying PLDLLA Anchor Fixation in Achilles Reconstruction for Insertional Tendinopathy.

PubMed

Boden, Stephanie A; Boden, Allison L; Mignemi, Danielle; Bariteau, Jason T

2018-04-01

Insertional Achilles tendinopathy (IAT) is a frequent cause of posterior heel pain and is often associated with Haglund's deformity. Surgical correction for refractory cases of IAT has been well studied; however, the method of tendon fixation to bone in these procedures remains controversial, and to date, no standard technique has been identified for tendon fixation in these surgeries. Often, after Haglund's resection, there is large exposed cancellous surface for Achilles reattachment, which may require unique fixation to optimize outcomes. Previous studies have consistently demonstrated improved patient outcomes after Achilles tendon reconstruction with early rehabilitation with protected weight bearing, evidencing the need for a strong and stable anchoring of the Achilles tendon that allows early weight bearing without tendon morbidity. In this report, we highlight the design, biomechanics, and surgical technique of Achilles tendon reconstruction with Haglund's deformity using a novel technique that utilizes ultrasonic energy to liquefy the suture anchor, allowing it to incorporate into surrounding bone. Biomechanical studies have demonstrated superior strength of the suture anchor utilizing this novel technique as compared with prior techniques. However, future research is needed to ensure that outcomes of this technique are favorable when compared with outcomes using traditional suture anchoring methods. Level V: Operative technique.

Biomechanical evaluation of a new fixation device for the thoracic spine.

PubMed

Hongo, Michio; Ilharreborde, Brice; Gay, Ralph E; Zhao, Chunfeng; Zhao, Kristin D; Berglund, Lawrence J; Zobitz, Mark; An, Kai-Nan

2009-08-01

The technology used in surgery for spinal deformity has progressed rapidly in recent years. Commonly used fixation techniques may include monofilament wires, sublaminar wires and cables, and pedicle screws. Unfortunately, neurological complications can occur with all of these, compromising the patients' health and quality of life. Recently, an alternative fixation technique using a metal clamp and polyester belt was developed to replace hooks and sublaminar wiring in scoliosis surgery. The goal of this study was to compare the pull-out strength of this new construct with sublaminar wiring, laminar hooks and pedicle screws. Forty thoracic vertebrae from five fresh frozen human thoracic spines (T5-12) were divided into five groups (8 per group), such that BMD values, pedicle diameter, and vertebral levels were equally distributed. They were then potted in polymethylmethacrylate and anchored with metal screws and polyethylene bands. One of five fixation methods was applied to the right side of the vertebra in each group: Pedicle screw, sublaminar belt with clamp, figure-8 belt with clamp, sublaminar wire, or laminar hook. Pull-out strength was then assessed using a custom jig in a servohydraulic tester. The mean failure load of the pedicle screw group was significantly larger than that of the figure-8 clamp (P = 0.001), sublaminar belt (0.0172), and sublaminar wire groups (P = 0.04) with no significant difference in pull-out strength between the latter three constructs. The most common mode of failure was the fracture of the pedicle. BMD was significantly correlated with failure load only in the figure-8 clamp and pedicle screw constructs. Only the pedicle screw had a statistically significant higher failure load than the sublaminar clamp. The sublaminar method of applying the belt and clamp device was superior to the figure-8 method. The sublaminar belt and clamp construct compared favorably to the traditional methods of sublaminar wires and laminar hooks, and should be considered as an alternative fixation device in the thoracic spine.

Biomechanical evaluation of a new fixation device for the thoracic spine

PubMed Central

Hongo, Michio; Ilharreborde, Brice; Zhao, Chunfeng; Zhao, Kristin D.; Berglund, Lawrence J.; Zobitz, Mark; An, Kai-Nan

2009-01-01

The technology used in surgery for spinal deformity has progressed rapidly in recent years. Commonly used fixation techniques may include monofilament wires, sublaminar wires and cables, and pedicle screws. Unfortunately, neurological complications can occur with all of these, compromising the patients’ health and quality of life. Recently, an alternative fixation technique using a metal clamp and polyester belt was developed to replace hooks and sublaminar wiring in scoliosis surgery. The goal of this study was to compare the pull-out strength of this new construct with sublaminar wiring, laminar hooks and pedicle screws. Forty thoracic vertebrae from five fresh frozen human thoracic spines (T5–12) were divided into five groups (8 per group), such that BMD values, pedicle diameter, and vertebral levels were equally distributed. They were then potted in polymethylmethacrylate and anchored with metal screws and polyethylene bands. One of five fixation methods was applied to the right side of the vertebra in each group: Pedicle screw, sublaminar belt with clamp, figure-8 belt with clamp, sublaminar wire, or laminar hook. Pull-out strength was then assessed using a custom jig in a servohydraulic tester. The mean failure load of the pedicle screw group was significantly larger than that of the figure-8 clamp (P = 0.001), sublaminar belt (0.0172), and sublaminar wire groups (P = 0.04) with no significant difference in pull-out strength between the latter three constructs. The most common mode of failure was the fracture of the pedicle. BMD was significantly correlated with failure load only in the figure-8 clamp and pedicle screw constructs. Only the pedicle screw had a statistically significant higher failure load than the sublaminar clamp. The sublaminar method of applying the belt and clamp device was superior to the figure-8 method. The sublaminar belt and clamp construct compared favorably to the traditional methods of sublaminar wires and laminar hooks, and should be considered as an alternative fixation device in the thoracic spine. PMID:19404687

Establishing a Surgical Procedure for Rhesus Epiretinal Scaffold Implantation with HiPSC-Derived Retinal Progenitors

PubMed Central

Luo, Ziming; Li, Kang; Li, Kaijing; Xian, Bikun; Liu, Ying; Yang, Sijing; Xu, Chaochao; Lu, Shoutao; Zhang, Haijun

2018-01-01

Background To develop an effective surgical procedure for cellular scaffold epiretinal implantation in rhesus, facilitating subsequent epiretinal stem cell transplantation. Methods Retinal progenitors were seeded onto a poly(lactic-co-glycolic) acid (PLGA) scaffold. First, the cellular scaffolds were delivered by 18G catheter or retinal forceps into rabbit epiretinal space (n = 50). Then, the cell survival rate was evaluated by Cell Counting Kit-8 (CCK-8). Second, three methods of scaffold fixation, including adhesion after gas-liquid exchange (n = 1), tamponade by hydrogel (n = 1), and fixation by retinal tacks (n = 4), were performed in rhesus monkeys. After one month, fundus photography and SD-OCT were performed to assess the outcomes, and histological examination was performed to evaluate proliferation. Results The cell survival rate was significantly higher in the catheter group. Follow-up examination showed that retinal tack fixation was the only method to maintain the scaffolds attached to host retina for at least 3 weeks, which is the minimal time required for cell integration. Histological staining demonstrated slight glial fibrillary acidic protein (GFAP) accumulation in the retinal tack insertion area. Conclusions The established surgical procedure offers a new insight into research of epiretinal cell replacement therapy in rhesus eyes. The successful delivery and long-term fixation provide a prerequisite for cell migration and integration. PMID:29760741

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

PubMed

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

2015-08-01

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

[Surgical treatment of tibial nonunion after wounding by high velocity missile and external fixators: a case report].

PubMed

Golubović, Ivan; Vukašinović, Zoran; Stojiljković, Predrag; Golubović, Zoran; Stojiljković, Danilo; Radovanović, Zoran; Ilić, Nenad; Najman, Stevo; Višnjić, Aleksandar; Arsić, Stojanka

2012-01-01

The missiles of modern firearms can cause severe fractures of the extremity. High velocity missile fractures of the tibia are characterized by massive tissue destruction and primary contamination with polymorphic bacteria. Treatment of these fractures is often complicated by delayed healing, poor position healing, nonhealing and bone tissue infection. We present the management of tibial nonunion after wounding by high velocity missile and primary treatment by external fixation in a 25-year-old patient. The patient was primarily treated with external fixation and reconstructive operations of the soft tissue without union of the fracture. Seven months after injury we placed a compression-distraction external fixator type Mitkovic and started with compression and distraction in the fracture focus after osteotomy of the fibula and autospongioplasty. We recorded satisfactory fracture healing and good functional outcome. Contamination and devitalization of the soft-tissue envelope increase the risk of infection and nonunion in fractures after wounding by high velocity missile. The use of the compression-distraction external fixator type Mitkovic may be an effective method in nonunions of the tibia after this kind of injury.

Inactivation of Lactobacillus rhamnosus GG by fixation modifies its probiotic properties.

PubMed

Markowicz, C; Kubiak, P; Grajek, W; Schmidt, M T

2016-01-01

Probiotics are microorganisms that have beneficial effects on the host and are safe for oral intake in a suitable dose. However, there are situations in which the administration of living microorganisms poses a risk for immunocompromised host. The objective of this study was to evaluate the influence of several fixation methods on selected biological properties of Lactobacillus rhamnosus GG that are relevant to its probiotic action. Fixation of the bacterial cells with ethanol, 2-propanol, glutaraldehyde, paraformaldehyde, and heat treatment resulted in a significant decrease of alkaline phosphatase, peroxidase, and β-galactosidase activities. Most of the fixation procedures reduced bacterial cell hydrophobicity and increased adhesion capacity. The fixation procedures resulted in a different perception of the bacterial cells by enterocytes, which was shown as changes in gene expression in enterocytes. The results show that some procedures of inactivation allow a fraction of the enzymatic activity to be maintained. The adhesion properties of the bacterial cells were enhanced, but the response of enterocytes to fixed cells was different than to live bacteria. Inactivation allows maintenance and modification of some of the properties of the bacterial cells.

[Scheimpflug photography for the examination of phakic intraocular lenses].

PubMed

Baumeister, M

2014-10-01

High myopia phakic intraocular lenses (IOL) have become an established means of surgical correction for high ametropia. Scheimpflug photography is one of the methods which are frequently applied for postoperative examination of the implants. Results from published studies employing Scheimpflug photography for examination of anterior chamber angle-fixated, iris-fixated and sulcus-fixated phakic IOLs were evaluated. In several published studies Scheimpflug photography was used to examine the position of the implant and opacification of the crystalline lens. The results provided valuable evidence for the improvement of phakic IOL design. Scheimpflug photography offers an easy to use, rapid non-contact examination of phakic IOLs.

Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: a series of 10 cases and surgical guidelines.

PubMed

Joshi, Samir; Kshirsagar, Rajesh; Mishra, Akshay; Shah, Rahul

2015-01-01

To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. All cases showed satisfactory bone healing without any growth disturbance. Open reduction and rigid internal fixation (ORIF) with 1.5 mm titanium mini- plates and 4 mm screws is a reliable and safe method in treatment of displaced paediatric mandibular fractures.

Passage of an Anterior Odontoid Screw through Gastrointestinal Tract.

PubMed

Leitner, L; Brückmann, C I; Gilg, M M; Bratschitsch, G; Sadoghi, P; Leithner, A; Radl, R

2017-01-01

Purpose . Anterior screw fixation has become a popular surgical treatment method for instable odontoid fractures. Screw loosening and migration are a rare, severe complication following anterior odontoid fixation, which can lead to esophagus perforation and requires revision operation. Methods . We report a case of screw loosening and migration after anterior odontoid fixation, which perforated the esophagus and was excreted without complications in a 78-year-old male patient. Results . A ventral dislocated anterior screw perforated through the esophagus after eight years after implantation and was excreted through the gastrointestinal (GI) tract. At a 6-month follow-up after the event the patient was asymptomatic. Conclusion . Extrusion via the GI tract is not safe enough to be considered as a treatment option for loosened screws. Some improvements could be implemented to prevent such an incident. Furthermore, this case is a fine example that recent preoperative imaging is mandatory before revision surgery for screw loosening.

Optimizing pediatric interdental fixation by use of a paramedian palatal fixation site.

PubMed

McNichols, Colton H; Hatef, Daniel A; Cole, Patrick D; Hollier, Larry H

2012-03-01

Condylar fractures are the most common injury seen in pediatric mandibular trauma. These injuries often cannot be adequately stabilized by conservative techniques such as splinting. The pediatric condyle fracture often requires a period of intermaxillary fixation. Because of the characteristics of the developing dentition, circumdental wiring is often not possible. Surgeons commonly achieve interdental stabilization by the connection of a circum-mandibular wire and a second wire placed through a drill hole in the piriform aperture. This method can be problematic in the young patient whose palatal suture is still patent. In this brief technical note, the use of a paramedian drill hole through the palate posterior to the maxillary incisors is described. It is believed that this method is superior to other techniques because it avoids injury to the deciduous tooth buds and allows for the maxillary wire to be seated in more structurally sound tissues.

Towards the identification of plant and animal binders on Australian stone knives.

PubMed

Blee, Alisa J; Walshe, Keryn; Pring, Allan; Quinton, Jamie S; Lenehan, Claire E

2010-07-15

There is limited information regarding the nature of plant and animal residues used as adhesives, fixatives and pigments found on Australian Aboriginal artefacts. This paper reports the use of FTIR in combination with the chemometric tools principal component analysis (PCA) and hierarchical clustering (HC) for the analysis and identification of Australian plant and animal fixatives on Australian stone artefacts. Ten different plant and animal residues were able to be discriminated from each other at a species level by combining FTIR spectroscopy with the chemometric data analysis methods, principal component analysis (PCA) and hierarchical clustering (HC). Application of this method to residues from three broken stone knives from the collections of the South Australian Museum indicated that two of the handles of knives were likely to have contained beeswax as the fixative whilst Spinifex resin was the probable binder on the third. Copyright 2010 Elsevier B.V. All rights reserved.

A Randomized Controlled Trial Comparing Suture-Fixation Mucopexy and Doppler-Guided Hemorrhoidal Artery Ligation in Patients with Grade III Hemorrhoids

PubMed Central

Zhai, Min; Zhang, Yong-An; Wang, Zhen-Yi; Sun, Jian-Hua; Wen, Jie; Zhang, Qi; Li, Jin-De; Wu, Yi-Zheng; Zhou, Feng; Xu, Hui-Lei

2016-01-01

Background. We aimed to evaluate the effectiveness of a suture-fixation mucopexy procedure by comparing with Doppler-guided hemorrhoidal artery ligation (DGHAL) in the management of patients with grade III hemorrhoids. Methods. This was a randomized controlled trial. One hundred patients with grade III hemorrhoids were randomly assigned to receive suture-fixation mucopexy (n = 50) or DGHAL (n = 50). Outcome assessments were performed at 2 weeks, 12 months, and 24 months. Assessments included resolution of clinical symptoms, postoperative complications, duration of hospitalization, and total costs. Results. At 2 weeks, one (2%) patient in suture-fixation group and four (8%) patients in DGHAL group had persistent prolapsing hemorrhoids. Postoperative bleeding was observed in two patients (4%) in suture-fixation group and one patient in DGHAL group. There was no significant difference in short-term recurrence between groups. Postoperative complications and duration of hospitalization were comparable between the two groups. Rates of recurrence of prolapse or bleeding at 12 months did not differ between groups. However, recurrence of prolapse at 24 months was significantly more common in DGHAL group (19.0% versus 2.3%, p = 0.030). Conclusions. Compared with DGHAL, the suture-fixation mucopexy technique had comparable short-term outcomes and favorable long-term outcomes. PMID:27066071

Use of resorbable plates and screws in pediatric facial fractures.

PubMed

Eppley, Barry L

2005-03-01

The use of resorbable plates and screws for fixation of pediatric facial fractures is both well tolerated and effective. It enables realignment and stable positioning of rapidly healing fracture segments while obviating any future issues secondary to long-term metal retention. Forty-four pediatric facial fractures were treated over a 10-year period at our institution using differing techniques of polymeric bone fixation. Twenty-nine mandible fractures in patients under the age of 10 (age range, 6 months to 8 years) were treated. Displaced fractures of the symphysis, parasymphysis, body, and ramus underwent open reduction and either 1.5-mm or 2.0-mm plate and screw fixation in 14 patients. Subcondylar fractures were treated by a short period of maxillomandibular fixation (3 weeks) achieved with suture ligation between resorbable screws placed at the zygoma and symphysis or a circummandibular suture attached to a zygomatic screw. Fifteen patients (age range, 4 to 11 years) with isolated frontal, supraorbital, intraorbital, or orbitozygomatic fractures were treated by open reduction and internal fixation with 1.5-mm resorbable plates, mesh, and screws. No long-term implant-related complications were seen in any of the treated patients. Resorbable polylactic and polyglycolic acid plates and screws can be an effective fixation method for facial fractures in children in the primary and secondary dentition periods.

Biomechanical investigation of different surgical strategies for the treatment of rib fractures using a three-dimensional human respiratory model.

PubMed

Shih, Kao-Shang; Truong, Thanh An; Hsu, Ching-Chi; Hou, Sheng-Mou

2017-11-02

Rib fracture is a common injury and can result in pain during respiration. Conservative treatment of rib fracture is applied via mechanical ventilation. However, ventilator-associated complications frequently occur. Surgical fixation is another approach to treat rib fractures. Unfortunately, this surgical treatment is still not completely defined. Past studies have evaluated the biomechanics of the rib cage during respiration using a finite element method, but only intact conditions were modelled. Thus, the purpose of this study was to develop a realistic numerical model of the human rib cage and to analyse the biomechanical performance of intact, injured and treated rib cages. Three-dimensional finite element models of the human rib cage were developed. Respiratory movement of the human rib cage was simulated to evaluate the strengths and limitations of different scenarios. The results show that a realistic human respiratory movement can be simulated and the predicted results were closely related to previous study (correlation coefficient>0.92). Fixation of two fractured ribs significantly decreased the fixation index (191%) compared to the injured model. This fixation may provide adequate fixation stability as well as reveal lower bone stress and implant stress compared with the fixation of three or more fractured ribs.

Stabilization of an acetabular fracture with cables for acute total hip arthroplasty.

PubMed

Mears, D C; Shirahama, M

1998-01-01

A critical stage of total hip arthroplasty for an acute acetabular fracture where extensive comminution, impaction, and osteopenia thwart the application of conventional open or closed methods, especially in the elderly, is stable fixation of the acetabulum. The use of 2-mm braided cables permits effective immobilization of the fracture for use in conjunction with a hybrid arthroplasty. The method is consistent with the use of a conventional arthroplastic incision and is suitable for other applications including the fixation of periprosthetic fractures, bulk allografts, and conventional acetabular fractures.

Nitrogen fixation method and apparatus

DOEpatents

Chen, Hao-Lin

1983-01-01

A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

Nitrogen fixation method and apparatus

DOEpatents

Chen, H.L.

1983-08-16

A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O[sub 2]/cm promotes the formation of vibrationally excited N[sub 2]. Atomic oxygen interacts with vibrationally excited N[sub 2] at a much quicker rate than unexcited N[sub 2], greatly improving the rate at which NO is formed. 1 fig.

System and method for 3D printing of aerogels

DOEpatents

Worsley, Marcus A.; Duoss, Eric; Kuntz, Joshua; Spadaccini, Christopher; Zhu, Cheng

2016-03-08

A method of forming an aerogel. The method may involve providing a graphene oxide powder and mixing the graphene oxide powder with a solution to form an ink. A 3D printing technique may be used to write the ink into a catalytic solution that is contained in a fluid containment member to form a wet part. The wet part may then be cured in a sealed container for a predetermined period of time at a predetermined temperature. The cured wet part may then be dried to form a finished aerogel part.

Comparison of Digestion Methods for the Determination of Trace Elements and Heavy Metals in Human Hair and Nails

PubMed Central

Ishak, Ismarulyusda; Rosli, Farah Dayana; Mohamed, Jamaludin; Mohd Ismail, Muhammad Faiz

2015-01-01

Background Microwave is the most reliable sample digestion method. However, it requires expensive microwave digester automation and has relatively low productivity. In this study, three non-automated digestion methods, i.e. wet acid digestion using nitric acid (HNO3) and hydrogen peroxide (H2O2), wet acid digestion using HNO3, and dry washing, are compared in order to determine the best approach. Methods Certified reference material IAEA-086 (International Atomic Energy Agency, Austria) and hair and nail samples from 20 female students of Universiti Kebangsaan Malaysia, aged 19 to 30 years, were collected and analysed using the three digestion methods. Results For hair samples, analysis of variance of repeated measures showed significant differences in the level of all elements (P < 0.001) between the three methods. For nail samples, only the copper (Cu) level showed no significant difference (P = 0.100) between methods. Wet acid digestion using HNO3 and H2O2 showed the best within- and between-run relative standard deviation (RSD) values, with within-run RSD for all elements, except for selenium (Se), < 5%. The between-run precision ranges from 6.14% to 17.96% for hair and from 3.53% to 11.52% for nail samples. Wet acid digestion using HNO3 and H2O2 showed both good accuracy and precision for manganese (Mn) and magnesium (Mg), with percentage recoveries of 110% and 96.9%, respectively. All elements show higher method detection limit (MDL) values than the previous study: 0.05 μg/g Mg for wet acid digestion using HNO3, 0.02 μg/g Se for wet acid digestion using HNO3 and H2O2, and 0.2 μg/g Mg for dry ash method. Conclusion Wet acid digestion using HNO3 and H2O2 proved to be the best method in terms of precision, accuracy, recovery, and MDL. However, only Mn and Mg showed adequate precision, accuracy, and percentage of recovery. PMID:28223880

Gaze3DFix: Detecting 3D fixations with an ellipsoidal bounding volume.

PubMed

Weber, Sascha; Schubert, Rebekka S; Vogt, Stefan; Velichkovsky, Boris M; Pannasch, Sebastian

2017-10-26

Nowadays, the use of eyetracking to determine 2-D gaze positions is common practice, and several approaches to the detection of 2-D fixations exist, but ready-to-use algorithms to determine eye movements in three dimensions are still missing. Here we present a dispersion-based algorithm with an ellipsoidal bounding volume that estimates 3D fixations. Therefore, 3D gaze points are obtained using a vector-based approach and are further processed with our algorithm. To evaluate the accuracy of our method, we performed experimental studies with real and virtual stimuli. We obtained good congruence between stimulus position and both the 3D gaze points and the 3D fixation locations within the tested range of 200-600 mm. The mean deviation of the 3D fixations from the stimulus positions was 17 mm for the real as well as for the virtual stimuli, with larger variances at increasing stimulus distances. The described algorithms are implemented in two dynamic linked libraries (Gaze3D.dll and Fixation3D.dll), and we provide a graphical user interface (Gaze3DFixGUI.exe) that is designed for importing 2-D binocular eyetracking data and calculating both 3D gaze points and 3D fixations using the libraries. The Gaze3DFix toolkit, including both libraries and the graphical user interface, is available as open-source software at https://github.com/applied-cognition-research/Gaze3DFix .

Biometric recognition via fixation density maps

NASA Astrophysics Data System (ADS)

Rigas, Ioannis; Komogortsev, Oleg V.

2014-05-01

This work introduces and evaluates a novel eye movement-driven biometric approach that employs eye fixation density maps for person identification. The proposed feature offers a dynamic representation of the biometric identity, storing rich information regarding the behavioral and physical eye movement characteristics of the individuals. The innate ability of fixation density maps to capture the spatial layout of the eye movements in conjunction with their probabilistic nature makes them a particularly suitable option as an eye movement biometrical trait in cases when free-viewing stimuli is presented. In order to demonstrate the effectiveness of the proposed approach, the method is evaluated on three different datasets containing a wide gamut of stimuli types, such as static images, video and text segments. The obtained results indicate a minimum EER (Equal Error Rate) of 18.3 %, revealing the perspectives on the utilization of fixation density maps as an enhancing biometrical cue during identification scenarios in dynamic visual environments.

Biomechanical Analysis of the Efficacy of Locking Plates during Cyclic Loading in Metacarpal Fractures

PubMed Central

Meffert, Rainer H.; Raschke, Michael J.; Blunk, Torsten; Ochman, Sabine

2014-01-01

Purpose. To analyse the biomechanical characteristics of locking plates under cyclic loading compared to a nonlocking plate in a diaphyseal metacarpal fracture. Methods. Oblique diaphyseal shaft fractures in porcine metacarpal bones were created in a biomechanical fracture model. An anatomical reduction and stabilization with a nonlocking and a comparable locking plate in mono- or bicortical screw fixation followed. Under cyclic loading, the displacement, and in subsequent load-to-failure tests, the maximum load and stiffness were measured. Results. For the monocortical screw fixation of the locking plate, a similar displacement, maximum load, and stiffness could be demonstrated compared to the bicortical screw fixation of the nonlocking plate. Conclusions. Locking plates in monocortical configuration may function as a useful alternative to the currently common treatment with bicortical fixations. Thereby, irritation of the flexor tendons would be avoided without compromising the stability, thus enabling the necessary early functional rehabilitation. PMID:24757429

Ab-interno scleral suture loop fixation with cow-hitch knot in posterior chamber intraocular lens decentration

PubMed Central

Can, Ertuğrul; Koçak, Nurullah; Yücel, Özlem Eşki; Gül, Adem; Öztürk, Hilal Eser; Sayın, Osman

2016-01-01

Aim of Study: To describe a simplified ab-interno cow-hitch suture fixation technique for repositioning decentered posterior chamber intraocular lens (PC IOL). Materials and Methods: Two cases are presented with the surgical correction of decentered and subluxated IOL. Ab-interno scleral suture fixation technique with hitch-cow knot in the eye was performed with a ciliary sulcus guide instrument and 1 year follow-up was completed. Results: Both of the patients had well centered lenses postoperatively. Corrected distant and near visual acuities of the patients were improved. There was no significant postoperative complication. In the follow-up period of 1 year, no evidence of suture erosion was found. Conclusions: Ab-interno scleral suture loop fixation with hitch-cow knot in the eye was effective in repositioning decentered or subluxated PC IOLs with excellent postoperative centered lenses and visual outcomes. PMID:27050346

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

T.F. Trembach; A.G. Klimenko

Coke transportation after wet slaking is accompanied by the release of dust in the production building and in the surrounding atmosphere. Wet methods are traditionally used to purify very humid air. Giprokoks has developed designs for highly efficient dry dust-removal methods in such conditions.

Prediction of the wetting-induced collapse behaviour using the soil-water characteristic curve

NASA Astrophysics Data System (ADS)

Xie, Wan-Li; Li, Ping; Vanapalli, Sai K.; Wang, Jia-Ding

2018-01-01

Collapsible soils go through three distinct phases in response to matric suction decrease during wetting: pre-collapse phase, collapse phase and post-collapse phase. It is reasonable and conservative to consider a strain path that includes a pre-collapse phase in which constant volume is maintained and a collapse phase that extends to the final matric suction to be experienced by collapsible soils during wetting. Upon this assumption, a method is proposed for predicting the collapse behaviour due to wetting. To use the proposed method, two parameters, critical suction and collapse rate, are required. The former is the suction value below which significant collapse deformations take place in response to matric suction decease, and the later is the rate at which void ratio reduces with matric suction in the collapse phase. The value of critical suction can be estimated from the water-entry value taking account of both the microstructure characteristics and collapse mechanism of fine-grained collapsible soils; the wetting soil-water characteristic curve thus can be used as a tool. Five sets of data of wetting tests on both compacted and natural collapsible soils reported in the literature were used to validate the proposed method. The critical suction values were estimated from the water-entry value with parameter a that is suggested to vary between 0.10 and 0.25 for compacted soils and to be lower for natural collapsible soils. The results of a field permeation test in collapsible loess soils were also used to validate the proposed method. The relatively good agreement between the measured and estimated collapse deformations suggests that the proposed method can provide reasonable prediction of the collapse behaviour due to wetting.

Fixation stability of the upward gaze in patients with myasthenia gravis: an eye-tracker study

PubMed Central

Mihara, Miharu; Hayashi, Atsushi; Fujita, Kazuya; Kakeue, Ken; Tamura, Ryoi

2017-01-01

Objective To quantify fixation stability of the upward gaze in patients with myasthenia gravis (MG) using an eye tracker. Methods and analysis In this study, 21 normal subjects, 5 patients with MG with diplopia, 5 patients with MG without diplopia and 6 patients with superior oblique (SO) palsy were included. Subjects fixated on a target in the upward direction for 1 min. The horizontal (X) and vertical (Y) eye positions were recorded using an eye tracker. Fixation stability was first quantified using the bivariate contour ellipse areas (BCEA) of fixation points as an index of whole stability. Then, the SDs of the X and Y eye positions (SDX and SDY, respectively) were quantified as indices of directional stability, with the data divided into three 20 s fractions to detect temporal fixation fluctuation. Results BCEAs were larger in patients with MG (both with and without diplopia) than normal subjects and patients with SO palsy, without significant differences among the three 20 s fractions. Compared with normal subjects, SDXs were larger only in patients with MG with diplopia; SDYs were larger in both patients with MG with and without diplopia. In addition, SDYs in patients with MG with diplopia were larger than those in patients with MG without diplopia and patients with SO palsy. Furthermore, a significant difference among the three 20 s fractions was detected for SDYs in patients with MG with diplopia. Conclusion Patients with MG, especially those with diplopia, exhibit fixation instability in the upward gaze. Non-invasive quantification of fixation stability with an eye tracker is useful for precisely identifying MG-specific fatigue characteristics. Trial registration number UMIN000023468; pre-results. PMID:29354719

Preauricular transmasseteric anteroparotid approach for extracorporeal fixation of mandibular condyle fractures

PubMed Central

Gali, Rajasekhar; Devireddy, Sathya Kumar; Venkata, Kishore Kumar Rayadurgam; Kanubaddy, Sridhar Reddy; Nemaly, Chaithanyaa; Dasari, Mallikarjuna

2016-01-01

Introduction: Free grafting or extracorporeal fixation of traumatically displaced mandibular condyles is sometimes required in patients with severe anteromedial displacement of condylar head. Majority of the published studies report the use of a submandibular, retromandibular or preauricular incisions for the access which have demerits of limited visibility, access and potential to cause damage to facial nerve and other parotid gland related complications. Purpose: This retrospective clinical case record study was done to evaluate the preauricular transmasseteric anteroparotid (P-TMAP) approach for open reduction and extracorporeal fixation of displaced and dislocated high condylar fractures of the mandible. Patients and Methods: This retrospective study involved search of clinical case records of seven patients with displaced and dislocated high condylar fractures treated by open reduction and extracorporeal fixation over a 3-year period. The parameters assessed were as follows: a) the ease of access for retrieval, reimplantation and fixation of the proximal segment; b) the postoperative approach related complications; c) the adequacy of anatomical reduction and stability of fixation; d) the occlusal changes; and the e) TMJ function and radiological changes. Results: Accessibility and visibility were good. Accurate anatomical reduction and fixation were achieved in all the patients. The recorded complications were minimal and transient. Facial nerve (buccal branch) palsy was noted in one patient with spontaneous resolution within 3 months. No cases of sialocele or Frey's syndrome were seen. Conclusion: The P-TMAP approach provides good access for open reduction and extracorporeal fixation of severely displaced condylar fractures. It facilitates retrieval, transplantation, repositioning, fixing the condyle and also reduces the chances of requirement of a vertical ramus osteotomy. It gives straight-line access to condylar head and ramus thereby permitting perpendicular placement of screws with minimal risk of damage to the facial nerve. PMID:27274123

Evaluation of the syndesmotic-only fixation for Weber-C ankle fractures with syndesmotic injury

PubMed Central

Mohammed, R; Syed, S; Metikala, S; Ali, SA

2011-01-01

Background: With the length of the fibula restored and the syndesmosis reduced anatomically, internal fixation using a plating device may not be necessary for supra-syndesmotic fibular fractures combined with diastasis of inferior tibio-fibular joint. A retrospective observational study was performed in patients who had this injury pattern treated with syndesmosis-only fixation. Materials and Methods: 12 patients who had Weber type-C injury pattern were treated with syndesmosis only fixation. The treatment plan was followed only if the fibular length could be restored and if the syndesmosis could be anatomically reduced. Through a percutaneous or mini-open reduction and clamp stabilization of the syndesmosis, all but one patient had a single tricortical screw fixation across the syndesmosis. Patients were kept non-weight-bearing for 6 weeks, followed by screw removal at an average of 8 weeks. Outcomes were assessed using an objective ankle scoring system (Olerud and Molander scale) and by radiographic assessment of the ankle mortise. Results: At a mean follow-up of 13 months, the functional outcome score was 75. Excellent to good outcomes were noted in 83% of the patients. Ankle mortise was reduced in all cases, and all but one fibular fracture united without loss of fixation. Six patients had more than one malleolar injury, needing either screw or anchor fixations. One patient had late diastasis after removal of the syndesmotic screw and underwent revision surgery with bone grafting of the fibula. This was probably due to early screw removal, before union of the fibular fracture had occurred. Conclusion: We recommend syndesmosis-only fixation as an effective treatment option for a combination of syndesmosis disruption and Weber type-C lateral malleolar fractures. PMID:21886929

Comparing fixation used for calcaneal displacement osteotomies: a look at removal rates and cost.

PubMed

Lucas, Douglas E; Simpson, G Alex; Philbin, Terrence M

2015-02-01

The calcaneal displacement osteotomy is a procedure frequently used by foot and ankle surgeons for hindfoot angular deformity. Traditional techniques use compression screw fixation that can result in prominent hardware. While the results of the procedure are generally good, a common concern is the development of plantar heel pain related to prominent hardware. The primary purpose of this study is to retrospectively compare clinical outcomes of 2 fixation methods for the osteotomy. Secondarily a cost analysis will compare implant costs to hardware removal costs. Records were reviewed for patients who had undergone a calcaneal displacement osteotomy fixated with either lag screw or a locked lateral compression plate (LLCP). Neuropathy, previous ipsilateral calcaneus surgery, heel pad trauma, or incomplete radiographic follow-up were exclusionary. Thirty-two patients (19.4%) required hardware removal from the screw fixation group compared to 1 (1.6%) of the LLCP group, which is significant (P < .05). Time to radiographic healing was not significantly different (P = .87). The screw fixation group required more follow-up visits over a longer period of time (P < .05). Implant cost was remarkably different with screw fixation costing on average $247.12, compared to the LLCP costing $1175.59. Although the LLCP cost was significantly higher, cost savings were identified when the cost of removal and removal rates were included. This study demonstrates that this device provides adequate stabilization for healing in equivalent time to screw fixation. The LLCP required decreased rates of hardware removal with fewer postoperative visits over a shorter period of time. Significant savings were demonstrated in the LLCP group despite the higher implant cost. Therapeutic, Level III, Retrospective Comparative Study. © 2014 The Author(s).

Restoring Tropical Grassland Productivity with Facilitated Biofertilisation

NASA Astrophysics Data System (ADS)

Williams, Wendy; Büdel, Burkhard

2015-04-01

Grazing is the major economic activity in northern Australia's subtropical grasslands, savannah and shrublands that cover >1.9 million km2 however; there has been significant decline in soil fertility that has led to the need to consider ways to improve management. Terrestrial cyanobacteria primarily inhabit complex soil microbial communities that drive physical and biological processes in the topsoil. These microbes facilitate resilience to drought and maintain soil function. They transform their environment through the secretion of mucilaginous organic compounds that improve aggregate stability, porosity, rainfall infiltration rates and water storage, reduce evaporation and soil erosion and, improve seedling emergence. In the northern Australian savannah cyanobacterial communities dominate soil surfaces of the perennial tussock grasslands. The core focus of this research has been to better understand the function of cyanobacteria within the climate-soil-plant ecosystem. The recent discovery that cyanobacteria are programmed to detect and respond only to wet season rains, and remain inactive and unproductive during the dry season even if it rains, has rewritten our understanding of soil nutrient cycles in the northern Australian savannah. In this project we have established: 1. For the wet season trials (Dec 2009-May 2010) the mean values of cyanobacterial crust (0-1 cm depth; n=100) plant-available N fluctuated, yet significantly increased incrementally from Dec to Feb (2.74 ± 0.37SE-5.62 ± 0.82 mg NH4+ kg-1 soil; p = 0.003) and peaked from Mar-May (9.59 ± 1.5SE-16.04 ± 3.2SE mg NH4+ kg-1 soil; p = 0.127) that represented the concluding stages of the wet season. 2. Cyanobacterial rates of N-fixation (determined by Acetylene Reduction assays, n=6 per month), increased significantly from the commencement to the height of the wet season (13.2 ± 2.9SE-30.2 ± 1.9SE kg N ha-1; p = 0.001) and decreased towards the end of the wet season (10.4 ± 1.8SE kg N ha-1; p = 0.000). 3. Average cyanobacterial biomass (Chlorophyll a) increased from 112.1 ± 21.3SE µg Ca g-1 soil (Nov) throughout the wet season; peaked in Feb (171.9 ± 2.4SE µg Ca g-1 soil) and declined towards the end of the wet season (153.8 ± 19.9SE µg Ca g-1 soil). 4. Diversity was underpinned by an abundance of the N-fixing cyanobacteria - Scytonema, Nostoc and Stigonema. We studied net productivity throughout the wet season and estimated that in these environments cyanobacteria contribute 40-50 kg N ha-1 to soil fertility in this time. Peak biofertilisation occurred at the height of the wet season (Feb-Mar). This seasonal pattern was also present in carbon sequestration data from parallel research at the same study site (Büdel and Williams' unpublished data). These studies suggest that such well-defined seasonal trends and synchrony in cyanobacterial-mediated C and N cycling significantly contributes to pasture plant production and soil fertility in the northern Australian savannah.

Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices

PubMed Central

MacLeod, A.; Simpson, A. H. R. W.

2018-01-01

Objectives Secondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs. Methods Synthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests. Results The method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface. Conclusions This study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition. Cite this article: A. MacLeod, A. H. R. W. Simpson, P. Pankaj. Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices. Bone Joint Res 2018;7:111–120. DOI: 10.1302/2046-3758.71.BJR-2017-0074.R2. PMID:29363522

The initial safe range of motion of the ankle joint after three methods of internal fixation of simulated fractures of the medial malleolus.

PubMed

Shimamura, Yoshio; Kaneko, Kazuo; Kume, Kazuhiko; Maeda, Mutsuhiro; Iwase, Hideaki

2006-07-01

Previous studies have demonstrated the safe passive range of ankle motion for inter-bone stiffness after internal fixation under load but there is a lack of information about the safe range of ankle motion for early rehabilitation in the absence of loading. The present study was designed to assess the effect of ankle movement on inter-bone displacement characteristics of medial malleolus fractures following three types of internal fixation to determine the safe range of motion. Five lower legs obtained during autopsy were used to assess three types of internal fixation (two with Kirschner-wires alone; two with Kirschner-wires plus tension band wiring; and, one with an AO/ASIF malleolar screw alone). Following a simulated fracture by sawing through the medial malleolus the displacement between the fractured bone ends was measured during a passive range of movement with continuous monitoring using omega (Omega) shaped transducers and a biaxial flexible goniometer. Statistical analysis was performed with repeated measures analysis of variance. Inter-bone displacement was not proportional to the magnitude of movement throughout the range of ankle motion as, when separation exceeded 25 microm, there was increasingly wide separation as plantar-flexion or dorsal-flexion was increased. There was no statistical significant difference between the small amount of inter-bone displacement observed with three types of fixation within the safe range of dorsal-flexion and plantar-flexion for early rehabilitation. However the inter-bone separation when fixation utilized two Kirschner-wires alone tended to be greater than when using the other two types of fixation during dorsal-flexion and eversion. The present study revealed a reproducible range of ankle motion for early rehabilitation which was estimated to be within the range of 20 degrees of dorsal-flexion and 10 degrees of plantar-flexion without eversion. Also, internal fixation with two Kirschner-wires alone does not seem to provide stability achieved by the other two forms of fixation.

Treatment of unstable distal radius fractures: non-invasive dynamic external fixator versus volar locking plate – functional and radiological outcome in a prospective case-controlled series

PubMed Central

Bajwa, Ali S.; Rammappa, Manju; Lee, Ling; Nanda, Rajesh

2015-01-01

Introduction: Distal radius fracture (DRF) is a common injury and various treatment modalities including open reduction and internal fixation (ORIF) with volar locking plate are available. More recently, a non-invasive external fixator has been used. Aims: To prospectively compare the use of a non-invasive external fixator with early dynamisation for DRF against ORIF with volar locking plate control group. Methods: Consecutive patients with closed DRF were included in a prospective case-controlled study. Patients were assigned to non-invasive external fixator or ORIF. Minimum follow-up was two years. Follow-up was at weeks 2, 4, 6, 8, 12, 26 and at one and two-year post-operatively. The outcome measures included demographic details, injury mechanism, AO fracture type, risk factors, body mass index (BMI), ulnar styloid fracture and dorsal comminution, radiographs, grip strength and DASH score. Results: Consecutive 50 patients were treated either with non-invasive external fixator (25/50) or with ORIF (25/50) and the mean age of the two groups was 53 years (SD 17.1) and 49 years (SD 19.5), respectively. Demographics were matched in two groups. In the non-invasive external fixator group, there were 10 AO Type-A, 5 Type-B and 10 Type-C fractures. The ORIF group included 8 Type-A, 6 Type-B and 11 Type-C fractures. The mean DASH score at three-months and one-year post-injury in non-invasive fixator group was 12.2 (SD 3.1) and 3.5 (SD 0.7), respectively, significantly greater than those of ORIF group 14.5 (SD 5.6) and 11.2 (SD 4.4), respectively (p < 0.05). Conclusion: DRF treated with non-invasive external fixator can give functional results superior to ORIF at three-months and the trend is maintained at one and two-year post-operatively. PMID:27163089

Volar plate fixation failure for volar shearing distal radius fractures with small lunate facet fragments.

PubMed

Beck, John D; Harness, Neil G; Spencer, Hillard T

2014-04-01

To determine the percentage of AO B3 distal radius fractures that lose reduction after operative fixation and to see whether fracture morphology, patient factors, or fixation methods predict failure. We hypothesized that initial fracture displacement, amount of lunate facet available for fixation, plate position, and screw fixation would be significant risk factors for loss of reduction. A prospective, observational review was conducted of 51 patients (52 fractures) with AO B3 (volar shearing) distal radius fractures treated operatively between January 2007 and June 2012. We reviewed a prospective distal radius registry to determine demographic data, medical comorbidities, and physical examination findings. Radiographs were evaluated for AO classification, loss of reduction, length of volar cortex available for fixation, and adequacy of stabilization of the lunate facet fragment with a volar plate. Preoperative data were compared between patients who maintained radiographic alignment and those with loss of reduction. A multivariate logistic regression analysis was completed to determine significant predictors of loss of reduction. Volar shearing fractures with separate scaphoid and lunate facet fragments (AO B3.3), preoperative lunate subsidence distance, and length of volar cortex available for fixation were significant predictors for loss of reduction; the latter was significant in multivariate analysis. Plate position and number of screws used to stabilize the lunate facet were not statistically different between groups. Patients with AO B3.3 fractures with less than 15 mm of lunate facet available for fixation, or greater than 5 mm of initial lunate subsidence, are at risk for failure even if a volar plate is properly placed. In these cases, we recommend additional fixation to maintain reduction of the small volar lunate facet fracture fragments in the form of plate extensions, pins, wires, suture, wire forms, or mini screws. Therapeutic III. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Analysis of initial fixation strength of press-fit fixation technique in anterior cruciate ligament reconstruction. A comparative study with titanium and bioabsorbable interference screw using porcine lower limb.

PubMed

Lee, Myung Chul; Jo, Hyunchul; Bae, Tae-Soo; Jang, Jin Dae; Seong, Sang Cheol

2003-03-01

We performed a controlled laboratory study to evaluate the initial fixation strength of press-fit technique. Forty porcine lower limbs were used and divided into four groups according to the method of fixation; group 1 (press-fit+1.4 mm), in which the diameter difference between the bone plug and the femoral tunnel was 1.4 mm; group 2 (press-fit+1.4 mm, 30 degrees), in which the diameter difference was the same with group 1, but the tensile loading axis was 30 degrees away from the long axis of the femoral tunnel; group 3 (titanium), in which a titanium interference screw was used for fixation; group 4 (bioabsorbable), in which a bioabsorbable interference screw was used for fixation. The graft in the press-fit group was harvested with a hollow oscillating saw with inner diameter of 9.4 mm to obtain consistent and completely circular shape of the bone plug. The femoral tunnel with diameter of 8 mm was drilled at the original ACL insertion. Following the bone plug insertion into the femoral tunnel and applying a preload of 20 N, the specimen underwent 500 loading cycles between 0 and 2 mm of displacement. Thereafter the specimen was loaded to failure. There was no fixation site failure during the cyclic loading test. Significant differences in the stiffness, linear load, or failure mode among the groups were not found. The average ultimate failure load of group 1 and group 2 were not significantly different from those of group 3 and group 4. The press-fit groups demonstrated sufficient fixation strength for the rehabilitation and interference screw groups. The completely circular shape of the bone plug and increased diameter difference between the bone plug and the femoral tunnel seemed to contribute to the strong fixation.

Evaluation of two commercial and three home-made fixatives for the substitution of formalin: a formaldehyde–free laboratory is possible

PubMed Central

2012-01-01

Background Formaldehyde (HCHO) is a gas (available as a 37% concentrated solution, stabilized with methanol). The 10% dilution (approximately 4% formaldehyde) has been used as a fixative since the end of the 19th century. Alternative fixatives are also commercially available or may be prepared in-house in laboratories. Statements by the IARC, along with other USA agencies (CalEPA, RoC/NTP) on the carcinogenicity of formaldehyde for humans renders its substitution in Pathology Departments necessary since the annual use of formalin may exceed 3,500 liters for a medium-large laboratory. To achieve a “formalin-free laboratory” we tested straightforward-to-make fixatives along with registered reagents offered as formalin substitutes. Methods More than two hundreds specimens were fixed in parallel with in-laboratory made fixatives PAGA (Polyethylenglycol, ethyl Alcohol, Glycerol, Acetic acid), two zinc-based fixatives (ZBF, Z7), and commercially-available alternatives (RCL2 and CellBlock). Tissue micro arrays were used for morphological and immunohistochemical comparison. Extraction of RNA was carried out to evaluate preservation of nucleic acids. Results Differences compared to formalin fixation were evident in alcohol-based fixatives, mainly restricted to higher stain affinity and considerable tissue shrinkage. Conversely, nuclear detail was superior with these alcohol-based formulas compared to formalin or glyoxale-based recipes. RNA extraction was superior for Z7, PAGA and RCL2 with regard to concentration but relatively comparable regarding quality. Conclusions Abolition of the human carcinogen formaldehyde from pathology laboratories is possible even in contexts whereby commercial alternatives to formalin are unavailable or are too expensive for routine use, and aspiration devices are lacking or not adequately serviced. The use of known formulations, possibly with simple and not-noxious (“alimentary grade”) constituents, comparable with registered proprietary products, may expand the search for the ideal fixative combining satisfactory morphology with improved preservation of nucleic acids and proteins as well as being easy and safe to dispose of. PMID:22947094

[Clinical application of percutaneous iliosacral screws combined with pubic ramus screws in Tile B pelvic fracture].

PubMed

Xu, Qi-Fei; Lin, Kui-Ran; Zhao, Dai-Jie; Zhang, Song-Qin; Feng, Sheng-Kai; Li, Chen

2017-03-25

To investigate the application and effect of minimally invasive percutaneous anterior pelvic pubic ramus screw fixation in Tile B fractures. A retrospective review was conducted on 56 patients with posterior pelvic ring injury combined with fractures of anterior pubic and ischiadic ramus treated between May 2010 and August 2015, including 31 males and 25 females with an average age of 36.8 years old ranging from 35 to 65 years old. Based on the Tile classification, there were 13 cases of Tile B1 type, 28 cases of Tile B2 type and 15 cases of Tile B3 type. Among them, 26 patients were treated with sacroiliac screws combined with external fixation (external fixator group) and the other 30 patients underwent sacroiliac screw fixation combined with anterior screw fixation (pubic ramus screw group). Postoperative complications, postoperative ambulation time, fracture healing, blood loss, Majeed pelvic function score and visual analogue scale(VAS) were compared between two groups. Fifty-four patients were followed up from 3 to 24 months with a mean of 12 months. There were no significant difference in the peri-operative bleeding and operation time between two groups( P >0.05). The postoperative activity time and fracture healing time of pubic ramus screw group were shorter than those of the external fixator group, the differences were statistically significant( P <0.05). The Majeed score, VAS score of pubic ramus screw group were higher than those of the external fixator group, the differences were statistically significant( P <0.05). The incidence of postoperative complications of pubic ramus screw was lower than that of the external fixator group, the difference was statistically significant ( P <0.05). Percutaneous iliosacral screws fixation combined with the pubic ramus screw is an effective and safty treatment method to the Tile B pelvic fracture. It has advantages of early ambulation, relief of the pain and few complications.

Curvature controlled wetting in two dimensions

NASA Astrophysics Data System (ADS)

Gil, Tamir; Mikheev, Lev V.

1995-07-01

A complete wetting transition at vanishing curvature of the substrate in two-dimensional circular geometry is studied by the transfer matrix method. We find an exact formal mapping of the partition function of the problem onto that of a (1+1)-dimensional wetting problem in planar geometry. As the radius of the substrate r0-->∞, the leading effect of the curvature is adding the Laplace pressure ΠL~r-10 to the pressure balance in the film. At temperatures and pressures under which the wetting is complete in planar geometry, Laplace pressure suppresses divergence of the mean thickness of the wetting layer lW, leading to a power law lW~r1/30. At a critical wetting transition of a planar substrate, curvature adds a relevant field; the corresponding multiscaling forms are readily available. The method allows for the systematic evaluation of corrections to the leading behavior; the next to the leading term reduces the thickness by the amount proportional to r-1/30

Tunable denture adhesives using biomimetic principles for enhanced tissue adhesion in moist environments.

PubMed

Gill, Simrone K; Roohpour, Nima; Topham, Paul D; Tighe, Brian J

2017-11-01

Nature provides many interesting examples of adhesive strategies. Of particular note, the protein glue secreted by marine mussels delivers high adhesion in wet and dynamic environments owing to existence of catechol moieties. As such, this study focuses on denture fixatives, where a non-zinc-containing commercial-based formulation has been judiciously modified by a biomimetic catechol-inspired polymer, poly(3,4-dihydroxystyrene/styrene-alt-maleic acid) in a quest to modulate adhesive performance. In vitro studies, in a lap-shear configuration, revealed that the catechol-modified components were able to enhance adhesion to both the denture base and hydrated, functional oral tissue mimic, with the resulting mode of failure prominently being adhesive rather than cohesive. These characteristics are desirable in prosthodontic fixative applications, for which temporary adhesion must be maintained, with ultimately an adhesive failure from the mucosal tissue surface preferred. These insights provide an experimental platform in the design of future biomimetic adhesive systems. Mussel adhesive proteins have proven to be promising biomimetic adhesive candidates for soft tissues and here for the first time we have adapted marine adhesive technology into a denture fixative application. Importantly, we have incorporated a soft tissue mimic in our in vitro adhesion technique that more closely resembles the oral mucosa than previously studied substrates. The novel biomimetic-modified adhesives showed the ability to score the highest adhesive bonding out of all the formulations included in this study, across all moisture levels. This paper will be of major interest to the Acta Biomaterialia readership since the study has illustrated the potential of biomimetic principles in the design of effective prosthodontic tissue adhesives in a series of purpose-designed in vitro experiments in the context of the challenging features of the oral environment. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Arthroscopically Assisted Minimally Invasive Fixation of a Type D2c Scapular Fracture].

PubMed

Kornherr, Patrick; Konerding, Christiane; Kovacevic, Mark; Wenda, Klaus

2018-06-12

Fractures of the scapula are rare and have an incidence of 1% of all fractures. Publications highlight glenoid rim fractures. Classification by Ideberg and Euler and Rüdi are accepted. Euler and Rüdi describe three extra-articular and two intra-articular fracture patterns. The indications for surgery are displaced glenoid fractures, scapula tilt of more than 40° and injuries to the superior shoulder suspensory complex. We describe a case of a 22 year old man, who while cycling collided with a moving car due to wet roads. After his admission to hospital as a polytraumatised patient, the trauma CT-Scan showed haemothorax with several associated rip fractures, displaced humeral shaft fracture and fractures of the acromion and glenoid, classified as type D2c according to Euler and Rüdi. Following damage control principles, drainage of the haemothorax was already performed in the ER and surgical treatment of the displaced humeral shaft fracture was performed on the day of admission. No peripheral neurological deficits were evident. After pulmonary stabilisation, surgery was performed 6 days later on the glenoid and acromion fracture, which in conjunction may be regarded as an injury to the superior shoulder suspensory complex. We performed an arthroscopically-assisted screw fixation of the glenoid fracture (type D2c according to Euler and Rüdi) and an ORIF procedure at the acromion. Postoperative rehabilitation was performed with passive abduction and elevation up to 90° for the first two weeks and active abduction an elevation up to 90° for weeks 3 to 6. Full ROM was allowed at week 7. Articular fractures of the glenoid are rare and mainly seen as rim fractures. The indications for surgery are displaced articular fractures and injury to the superior shoulder suspensory complex. As demonstrated by this article, type D2c fractures according to Euler and Rüdi can be treated effectively as an arthroscopically-assisted screw fixation procedure. Georg Thieme Verlag KG Stuttgart · New York.

Dinitrogen fixation associated with shoots of aquatic carnivorous plants: is it ecologically important?

PubMed Central

Sirová, Dagmara; Šantrůček, Jiří; Adamec, Lubomír; Bárta, Jiří; Borovec, Jakub; Pech, Jiří; Owens, Sarah M.; Šantrůčková, Hana; Schäufele, Rudi; Štorchová, Helena; Vrba, Jaroslav

2014-01-01

Background and Aims Rootless carnivorous plants of the genus Utricularia are important components of many standing waters worldwide, as well as suitable model organisms for studying plant–microbe interactions. In this study, an investigation was made of the importance of microbial dinitrogen (N2) fixation in the N acquisition of four aquatic Utricularia species and another aquatic carnivorous plant, Aldrovanda vesiculosa. Methods 16S rRNA amplicon sequencing was used to assess the presence of micro-organisms with known ability to fix N2. Next-generation sequencing provided information on the expression of N2 fixation-associated genes. N2 fixation rates were measured following 15N2-labelling and were used to calculate the plant assimilation rate of microbially fixed N2. Key Results Utricularia traps were confirmed as primary sites of N2 fixation, with up to 16 % of the plant-associated microbial community consisting of bacteria capable of fixing N2. Of these, rhizobia were the most abundant group. Nitrogen fixation rates increased with increasing shoot age, but never exceeded 1·3 μmol N g–1 d. mass d–1. Plant assimilation rates of fixed N2 were detectable and significant, but this fraction formed less than 1 % of daily plant N gain. Although trap fluid provides conditions favourable for microbial N2 fixation, levels of nif gene transcription comprised <0·01 % of the total prokaryotic transcripts. Conclusions It is hypothesized that the reason for limited N2 fixation in aquatic Utricularia, despite the large potential capacity, is the high concentration of NH4-N (2·0–4·3 mg L–1) in the trap fluid. Resulting from fast turnover of organic detritus, it probably inhibits N2 fixation in most of the microorganisms present. Nitrogen fixation is not expected to contribute significantly to N nutrition of aquatic carnivorous plants under their typical growth conditions; however, on an annual basis the plant–microbe system can supply nitrogen in the order of hundreds of mg m–2 into the nutrient-limited littoral zone, where it may thus represent an important N source. PMID:24817095

Rapid Prototyping Amphiphilic Polymer/Hydroxyapatite Composite Scaffolds with Hydration-Induced Self-Fixation Behavior

PubMed Central

Kutikov, Artem B.; Gurijala, Anvesh

2015-01-01

Two major factors hampering the broad use of rapid prototyped biomaterials for tissue engineering applications are the requirement for custom-designed or expensive research-grade three-dimensional (3D) printers and the limited selection of suitable thermoplastic biomaterials exhibiting physical characteristics desired for facile surgical handling and biological properties encouraging tissue integration. Properly designed thermoplastic biodegradable amphiphilic polymers can exhibit hydration-dependent hydrophilicity changes and stiffening behavior, which may be exploited to facilitate the surgical delivery/self-fixation of the scaffold within a physiological tissue environment. Compared to conventional hydrophobic polyesters, they also present significant advantages in blending with hydrophilic osteoconductive minerals with improved interfacial adhesion for bone tissue engineering applications. Here, we demonstrated the excellent blending of biodegradable, amphiphilic poly(D,L-lactic acid)-poly(ethylene glycol)-poly(D,L-lactic acid) (PLA-PEG-PLA) (PELA) triblock co-polymer with hydroxyapatite (HA) and the fabrication of high-quality rapid prototyped 3D macroporous composite scaffolds using an unmodified consumer-grade 3D printer. The rapid prototyped HA-PELA composite scaffolds and the PELA control (without HA) swelled (66% and 44% volume increases, respectively) and stiffened (1.38-fold and 4-fold increases in compressive modulus, respectively) in water. To test the hypothesis that the hydration-induced physical changes can translate into self-fixation properties of the scaffolds within a confined defect, a straightforward in vitro pull-out test was designed to quantify the peak force required to dislodge these scaffolds from a simulated cylindrical defect at dry versus wet states. Consistent with our hypothesis, the peak fixation force measured for the PELA and HA-PELA scaffolds increased 6-fold and 15-fold upon hydration, respectively. Furthermore, we showed that the low-fouling 3D PELA inhibited the attachment of NIH3T3 fibroblasts or bone marrow stromal cells while the HA-PELA readily supported cellular attachment and osteogenic differentiation. Finally, we demonstrated the feasibility of rapid prototyping biphasic PELA/HA-PELA scaffolds for potential guided bone regeneration where an osteoconductive scaffold interior encouraging osteointegration and a nonadhesive surface discouraging fibrous tissue encapsulation is desired. This work demonstrated that by combining facile and readily translatable rapid prototyping approaches with unique biomaterial designs, biodegradable composite scaffolds with well-controlled macroporosities, spatially defined biological microenvironment, and useful handling characteristics can be developed. PMID:25025950

Dermally adhered soil: 2. Reconstruction of dry-sieve particle-size distributions from wet-sieve data.

PubMed

Choate, LaDonna M; Ranville, James F; Bunge, Annette L; Macalady, Donald L

2006-10-01

In the evaluation of soil particle-size effects on environmental processes, particle-size distributions are measured by either wet or dry sieving. Commonly, size distributions determined by wet and dry sieving differ because some particles disaggregate in water. Whereas the dry-sieve distributions are most relevant to the study of soil adherence to skin, soil can be recovered from skin only by washing with the potential for disaggregation whether or not it is subsequently wet or dry sieved. Thus, the possibility exists that wet-sieving measurements of the particle sizes that adhered to the skin could be skewed toward the smaller fractions. This paper provides a method by which dry-sieve particle-size distributions can be reconstructed from wet-sieve particle-size distributions for the same soil. The approach combines mass balances with a series of experiments in which wet sieving was applied to dry-sieve fractions from the original soil. Unless the soil moisture content is high (i.e., greater than or equal to the water content after equilibration with water-saturated air), only the soil particles of diameters less than about 63 microm adhere to the skin. Because of this, the adhering particle-size distribution calculated using the reconstruction method was not significantly different from the wet-sieving determinations.

NC-AFM observation of atomic scale structure of rutile-type TiO2(110) surface prepared by wet chemical process.

PubMed

Namai, Yoshimichi; Matsuoka, Osamu

2006-04-06

We succeeded in observing the atomic scale structure of a rutile-type TiO2(110) single-crystal surface prepared by the wet chemical method of chemical etching in an acid solution and surface annealing in air. Ultrahigh vacuum noncontact atomic force microscopy (UHV-NC-AFM) was used for observing the atomic scale structures of the surface. The UHV-NC-AFM measurements at 450 K, which is above a desorption temperature of molecularly adsorbed water on the TiO2(110) surface, enabled us to observe the atomic scale structure of the TiO2(110) surface prepared by the wet chemical method. In the UHV-NC-AFM measurements at room temperature (RT), however, the atomic scale structure of the TiO2(110) surface was not observed. The TiO2(110) surface may be covered with molecularly adsorbed water after the surface was prepared by the wet chemical method. The structure of the TiO2(110) surface that was prepared by the wet chemical method was consistent with the (1 x 1) bulk-terminated model of the TiO2(110) surface.

Phytoplankton Productivity in an Arctic Fjord (West Greenland): Estimating Electron Requirements for Carbon Fixation and Oxygen Production

PubMed Central

Hancke, Kasper; Dalsgaard, Tage; Sejr, Mikael Kristian; Markager, Stiig; Glud, Ronnie Nøhr

2015-01-01

Accurate quantification of pelagic primary production is essential for quantifying the marine carbon turnover and the energy supply to the food web. Knowing the electron requirement (Κ) for carbon (C) fixation (Κ C) and oxygen (O2) production (Κ O2), variable fluorescence has the potential to quantify primary production in microalgae, and hereby increasing spatial and temporal resolution of measurements compared to traditional methods. Here we quantify Κ C and Κ O2 through measures of Pulse Amplitude Modulated (PAM) fluorometry, C fixation and O2 production in an Arctic fjord (Godthåbsfjorden, W Greenland). Through short- (2h) and long-term (24h) experiments, rates of electron transfer (ETRPSII), C fixation and/or O2 production were quantified and compared. Absolute rates of ETR were derived by accounting for Photosystem II light absorption and spectral light composition. Two-hour incubations revealed a linear relationship between ETRPSII and gross 14C fixation (R2 = 0.81) during light-limited photosynthesis, giving a Κ C of 7.6 ± 0.6 (mean ± S.E.) mol é (mol C)−1. Diel net rates also demonstrated a linear relationship between ETRPSII and C fixation giving a Κ C of 11.2 ± 1.3 mol é (mol C)−1 (R2 = 0.86). For net O2 production the electron requirement was lower than for net C fixation giving 6.5 ± 0.9 mol é (mol O2)−1 (R2 = 0.94). This, however, still is an electron requirement 1.6 times higher than the theoretical minimum for O2 production [i.e. 4 mol é (mol O2)−1]. The discrepancy is explained by respiratory activity and non-photochemical electron requirements and the variability is discussed. In conclusion, the bio-optical method and derived electron requirement support conversion of ETR to units of C or O2, paving the road for improved spatial and temporal resolution of primary production estimates. PMID:26218096

Design factors of femur fracture fixation plates made of shape memory alloy based on the Taguchi method by finite element analysis.

PubMed

Ko, Cheolwoong; Yang, Mikyung; Byun, Taemin; Lee, Sang-Wook

2018-05-01

This study proposed a way to design femur fracture fixation plates made of shape memory alloy based on computed tomography (CT) images of Korean cadaveric femurs. To this end, 3 major design factors of femur fracture fixation plates (circumference angle, thickness, and inner diameter) were selected based on the contact pressure when a femur fracture fixation plate was applied to a cylinder model using the Taguchi method. Then, the effects of the design factors were analyzed. It was shown that the design factors were statistically significant at a level of p = 0.05 concerning the inner diameter and the thickness. The factors affecting the contact pressure were inner diameter, thickness, and circumference angle, in that order. Particularly, in the condition of Case 9 (inner diameter 27 mm, thickness 2.4 mm, and circumference angle 270°), the max. average contact pressure was 21.721 MPa, while the min. average contact pressure was 3.118 MPa in Case 10 (inner diameter 29 mm, thickness 2.0 mm, and circumference angle 210°). When the femur fracture fixation plate was applied to the cylinder model, the displacement due to external sliding and pulling forces was analyzed. As a result, the displacement in the sliding condition was at max. 3.75 times greater than that in the pulling condition, which indicated that the cohesion strength between the femur fracture fixation plate and the cylinder model was likely to be greater in the pulling condition. When a human femur model was applied, the max. average contact pressure was 10.76 MPa, which was lower than the yield strength of a human femur (108 MPa). In addition, the analysis of the rib behaviors of the femur fracture fixation plate in relation to the recovery effect of the shape memory alloy showed that the rib behaviors varied depending on the arbitrarily curved shapes of the femur sections. Copyright © 2018 John Wiley & Sons, Ltd.

Closed-loop system for growth of aquatic biomass and gasification thereof

DOEpatents

Oyler, James R.

2017-09-19

Processes, systems, and methods for producing combustible gas from wet biomass are provided. In one aspect, for example, a process for generating a combustible gas from a wet biomass in a closed system is provided. Such a process may include growing a wet biomass in a growth chamber, moving at least a portion of the wet biomass to a reactor, heating the portion of the wet biomass under high pressure in the reactor to gasify the wet biomass into a total gas component, separating the gasified component into a liquid component, a non-combustible gas component, and a combustible gas component, and introducing the liquid component and non-combustible gas component containing carbon dioxide into the growth chamber to stimulate new wet biomass growth.

A Brief History of Limb Lengthening.

PubMed

Birch, John G

2017-09-01

In the last 35 years, orthopaedic surgeons have witnessed 3 major advances in the technique of limb lengthening: "distraction osteogenesis" facilitated by Gavriil Ilizarov method and infinitely-adaptable circular fixator with fine-wire bone fragment fixation; the introduction of the "6-strut" computer program-assisted circular fixators to effect complex deformity correction simultaneously; and the development of motorized intramedullary lengthening nails. However, the principles and associated complications of these techniques are on the basis of observations by Codivilla, Putti, and Abbott from as much as 110 years ago. This review notes the contribution of these pioneers in limb lengthening, and the contribution of Thor Heyerdahl principles of tolerance and diversity to the dissemination of Ilizarov principles to the Western world.

The concept and method of closed reduction and internal fixation: a new approach for the treatment of simple zygoma fractures.

PubMed

Uda, Hirokazu; Kamochi, Hideaki; Sugawara, Yasushi; Sarukawa, Syunji; Sunaga, Ataru

2013-11-01

The authors have developed a new minimally invasive surgical procedure for simple zygoma fractures, a closed reduction and internal fixation method, that uses a cannulated cortical screw system. From 2007 to 2012, 42 selected patients with simple zygoma fractures without ocular problems or shear at the zygomatic frontal portion were treated with this method. The mean age of the patients was 33 years (range, 13 to 77 years). The authors achieved good repositioning, equivalent to results achieved with conventional procedures in all cases. No notable complication occurred except for minor infection in two cases. Mean operative time was 32 minutes (range, 19 to 58 minutes). Postoperative relapse was found only in the posterior direction (p<0.001), but the distance of that was so small (mean, 0.47 mm) that it did not cause any problem clinically. Although further improvement might be needed, such as screw specification, the closed reduction and internal fixation method has many advantages: short operative time, less effect on soft tissue, maintenance of bone healing potential, and decreased postoperative pain and swelling. The authors concluded that this method has the potential to become a future surgical procedure for simple zygoma fractures. Therapeutic, IV.

Ultrasonically assisted anchoring of biodegradable implants for chevron osteotomies - clinical evaluation of a novel fixation method.

PubMed

Olms, Kai; Randt, Thorsten; Reimers, Nils; Zander, Nils; Schulz, Arndt P

2014-01-01

Reconstructive osteotomies for the treatment of Hallux valgus are among the most prevalent procedures in foot and ankle surgery. The combination of biodegradable materials with an innovative method for fixation by application of ultrasonic energy facilitates a new bonding method for fractures or osteotomies. As clinical experience is still limited, the aim of this study was to assess the safety and performance of the SonicPin system for fixation of Austin/Chevron osteotomies. Chevron osteotomy was performed on 30 patients for the treatment of Hallux valgus. The used SonicPins were made from polylactide and are selectively melted into the cancellous bone structure during insertion by ultrasonic energy. Patients were followed for one year, which included X-ray and MRI examinations as well as evaluation of life quality by EQ-5D (EuroQol). The MRI after three months showed adequate bone healing in all cases and no signs of foreign body reactions, which was again confirmed by MRI 12 months postoperatively. The bony healing after 12 months was uneventful without any signs of foreign body reactions. In summary, based on the low complication rate and the significant improvement in health related quality of life (EQ-5D) reported in this study, fixation of an Austin/Chevron osteotomy with a SonicPin for treatment of Hallux valgus can be considered to be safe and efficient over the short term. Therapeutic Level III.

Ultrasonically Assisted Anchoring of Biodegradable Implants for Chevron Osteotomies – Clinical Evaluation of a Novel Fixation Method

PubMed Central

Olms, Kai; Randt, Thorsten; Reimers, Nils; Zander, Nils; Schulz, Arndt P.

2014-01-01

Reconstructive osteotomies for the treatment of Hallux valgus are among the most prevalent procedures in foot and ankle surgery. The combination of biodegradable materials with an innovative method for fixation by application of ultrasonic energy facilitates a new bonding method for fractures or osteotomies. As clinical experience is still limited, the aim of this study was to assess the safety and performance of the SonicPin system for fixation of Austin/Chevron osteotomies. Chevron osteotomy was performed on 30 patients for the treatment of Hallux valgus. The used SonicPins were made from polylactide and are selectively melted into the cancellous bone structure during insertion by ultrasonic energy. Patients were followed for one year, which included X-ray and MRI examinations as well as evaluation of life quality by EQ-5D (EuroQol). The MRI after three months showed adequate bone healing in all cases and no signs of foreign body reactions, which was again confirmed by MRI 12 months postoperatively. The bony healing after 12 months was uneventful without any signs of foreign body reactions. In summary, based on the low complication rate and the significant improvement in health related quality of life (EQ-5D) reported in this study, fixation of an Austin/Chevron osteotomy with a SonicPin for treatment of Hallux valgus can be considered to be safe and efficient over the short term. Level of Clinical Evidence: Therapeutic Level III. PMID:24851140

Unicompartmental knee prostheses: in vitro wear assessment of the menisci tibial insert after two different fixation methods

NASA Astrophysics Data System (ADS)

Affatato, S.; Spinelli, M.; Zavalloni, M.; Carmignato, S.; Lopomo, N.; Marcacci, M.; Viceconti, M.

2008-10-01

Knee osteoarthritis is a complex clinical scenario where many biological and mechanical factors influence the severity of articular degenerative changes. Minimally invasive knee prosthetic surgery, with only a compartment replacement (unicompartmental knee replacement), might be a good compromise between osteotomy and total knee prosthesis. The focus of this study was to develop and validate a protocol to assess the fixation method of the femoral components in mechanical simulation, for pre-clinical validation; the wear behaviour of two different fixation frames was quantified and compared. In particular, two different wear tests were conducted using the same knee simulator, the same load profiles and the same kinematics; two different fixation methods were applied to the femoral sleds (synthetic femur and metal block). Surface characterization on both articulating bearings was performed by a roughness measuring machine and coordinate measuring machine. The wear produced by the tibial inserts using the synthetic femur was considerably higher than the wear registered by the metal-block holder. Roughness measurements on femoral sleds showed a limited number of scratches with high Rt values for the metal-block set-up; the damaged surface broadened in the case of femoral condyles and tibial inserts mounted on composite bone, but lower Rt and linear penetration values were measured. The two holding frames showed different wear activities as a consequence of dissimilar dynamic performance. Further observations should be made in vivo to prove the actual importance of synthetic bone simulations and specific material behaviour.

New fixation method for maxillary distraction osteogenesis using locking attachments.

PubMed

Suzuki, Eduardo Yugo; Buranastidporn, Boonsiva; Ishii, Masatoshi

2006-10-01

The external traction hooks of the intraoral splint used in the rigid external distraction (RED) system for maxillary distraction osteogenesis interfere with the surgical procedures. The purpose of this study is to introduce an innovative splint fixation method for maxillary distraction osteogenesis with Locking Attachments and evaluate their advantages, such as reduction of operating time compared with the traditional intraoral splint method. Retrospective comparison of operative times of maxillary Le Fort I osteotomy procedures was carried out with the traditional protocol using the intraoral splint cemented to the maxillary dentition (n = 14), and a removable intraoral splint that is inserted postsurgically (n = 14). Operative procedure times were compared and analyzed statistically using the data extracted from the surgical records. There were no complications inserting the removable splint postsurgically, including pain, discomfort, or time-consuming procedure. Stable and secure splint fixation was obtained before the distraction procedure and the desired treatment goals were obtained in all patients. The total operative procedure times were significantly reduced in the Locking Attachments group by 24% to 41% (approximately 65 minutes) compared with earlier operations involving the conventional splints (P < .05). Maxillary distraction osteogenesis with the Locking Attachments is a highly effective fixation approach to manage severe hypoplastic maxilla, eliminating lip constraints resulting from scarring and allowing for easier, more deliberate and careful dissection. The use of the Locking Attachments is reliable in craniofacial surgery and has proved to be advantageous in the reduction of the operating time and surgical risks.

Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study.

PubMed

Chen, Pengbo; Lu, Hua; Shen, Hao; Wang, Wei; Ni, Binbin; Chen, Jishizhan

2017-02-23

Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

PubMed

Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

2014-09-01

Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position. Copyright 2014, SLACK Incorporated.

Intramedullary nailing in opening wedge high tibial osteotomy-in vitro test for validation of a method of fixation.

PubMed

Burchard, Rene; Katerla, Denise; Hammer, Marina; Pahlkötter, Anke; Soost, Christian; Dietrich, Gerhard; Ohrndorf, Arne; Richter, Wolfgang; Lengsfeld, Markus; Christ, Hans-Jürgen; Graw, Jan Adriaan; Fritzen, Claus-Peter

2018-02-01

Opening wedge high tibial osteotomy (HTO) as a treatment in unicompartimental osteoarthritis of the knee can significantly relieve pain and prevent or at least delay an early joint replacement. The fixation of the osteotomy has undergone development and refinements during the last years. The angle-stable plate fixator is currently one of the most commonly used plates in HTOs. The angular stable fixation between screws and the plate offers a high primary stability to retain the correction with early weight-bearing protocols. This surgical technique is performed as a standard of care and generally well tolerated by the patients. Nevertheless, some studies observed that many patients complained about discomfort related to the implant. Therefore, the stability of two different intramedullary nails, a short implant used in humeral fractures and a long device used in tibial fractures for stabilization in valgus HTOs, was investigated as an alternative fixation technique. The plate fixator was defined as reference standard. Nine synthetic tibia models were standardly osteotomized and stabilized by one of the fixation devices. Axial compression was realized using a special testing machine and two protocols were performed: a multi-step fatigue test and a load-to-failure test. Overall motion, medial, and lateral displacements were documented. Fractures always occurred at the lateral cortex. Axial cyclic loading up to 800 N was tolerated by all implants without failure. The tibia nail provided highest fatigue strength under the load-to-failure conditions. The results suggest that intramedullary nailing might be used as an alternative concept in HTO.

Biomechanical analysis of two fixation methods for proximal chevron osteotomy of the first metatarsal.

PubMed

Schuh, Reinhard; Hofstaetter, Jochen Gerhard; Benca, Emir; Willegger, Madeleine; von Skrbensky, Gobert; Zandieh, Shahin; Wanivenhaus, Axel; Holinka, Johannes; Windhager, Reinhard

2014-05-01

The proximal chevron osteotomy provides high correctional power. However, relatively high rates of dorsiflexion malunion of up to 17 % are reported for this procedure. This leads to insufficient weight bearing of the first ray and therefore to metatarsalgia. Recent biomechanical and clinical studies pointed out the importance of rigid fixation of proximal metatarsal osteotomies. Therefore, the aim of the present study was to compare biomechanical properties of fixation of proximal chevron osteotomies with variable locking plate and cancellous screw respectively. Ten matched pairs of human fresh frozen cadaveric first metatarsals underwent proximal chevron osteotomy with either variable locking plate or cancellous screw fixation after obtaining bone mineral density. Biomechanical testing included repetitive plantar to dorsal loading from 0 to 31 N with the 858 Mini Bionix(®) (MTS(®) Systems Corporation, Eden Prairie, MN, USA). Dorsal angulation of the distal fragment was recorded. The variable locking plate construct reveals statistically superior results in terms of bending stiffness and dorsal angulation compared to the cancellous screw construct. There was a statistically significant correlation between bone mineral density and maximum tolerated load until construct failure occurred for the screw construct (r = 0.640, p = 0.406). The results of the present study indicate that variable locking plate fixation shows superior biomechanical results to cancellous screw fixation for proximal chevron osteotomy. Additionally, screw construct failure was related to levels of low bone mineral density. Based on the results of the present study we recommend variable locking plate fixation for proximal chevron osteotomy, especially in osteoporotic bone.

Mesh Displacement After Bilateral Inguinal Hernia Repair With No Fixation

PubMed Central

Rocha, Gabriela Moreira; Campos, Antonio Carlos Ligocki; Paulin, João Augusto Nocera; Coelho, Julio Cesar Uili

2017-01-01

Background and Objectives: About 20% of patients with inguinal hernia present bilateral hernias in the diagnosis. In these cases, laparoscopic procedure is considered gold standard approach. Mesh fixation is considered important step toward avoiding recurrence. However, because of cost and risk of pain, real need for mesh fixation has been debated. For bilateral inguinal hernias, there are few specific data about non fixation and mesh displacement. We assessed mesh movement in patients who had undergone laparoscopic bilateral inguinal hernia repair without mesh fixation and compared the results with those obtained in patients with unilateral hernia. Methods: From January 2012 through May 2014, 20 consecutive patients with bilateral inguinal hernia underwent TEP repair with no mesh fixation. Results were compared with 50 consecutive patients with unilateral inguinal hernia surgically repaired with similar technique. Mesh was marked with 3 clips. Mesh movements were measured by comparing initial radiography performed at the end of surgery, with a second radiographic scan performed 30 days later. Results: Mean movements of all 3 clips in bilateral nonfixation (NF) group were 0.15–0.4 cm compared with 0.1–0.3 cm in unilateral NF group. Overall displacement of bilateral and unilateral NF groups did not show significant difference. Mean overall displacement was 1.9 cm versus 1.8 cm in the bilateral and unilateral NF groups, respectively (P = .78). Conclusions: TEP with no mesh fixation is safe in bilateral inguinal repairs. Early mesh displacement is minimal. This technique can be safely used in most patients with inguinal hernia. PMID:28904521

Clinical comparative analysis on unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation.

PubMed

Li, C-L

2014-01-01

To investigate clinical efficacy of unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation. 64 patients with unstable pelvic fractures were selected in the hospital from January 2008 to June 2011, and were randomly divided into two groups.(32 patients with sacroiliac anterior plate fixation as the control group, and another 32 patients with percutaneous sacroiliac screw internal fixation as the observation group). The perioperative period clinical indicators, postoperative Matta score, postoperative Majeed function score of all patients were compared and analyzed. The operation time, intraoperative blood loss, wound total length, postoperative fever time, duration of hospitalization in the observation group were significantly less than those in the control group. The complication rate (3.1%) in the observation group was lower than that in the control group (21.9%). The rate of Matta score excellent (96.9%) in the observation group was higher than that in the control group (81.2%) after the treatment. The rate of Majeed function score excellent (93.8%) in the observation group was significantly higher than that in the control group (75%) after the treatment. Percutaneous sacroiliac screw internal fixation in the treatment of unstable pelvic fractures has less injury, less bleeding, less pain and rapid recovery which is a safe and effective minimally invasive operation method. The clinical curative effect of percutaneous sacroiliac screw internal fixation is better than anterior plate fixation for the treatment of sacroiliac joint. The full preparation before the surgery and patients with positive can substantially reduce the occurrence of complications rate.

MR elastography to measure the effects of cancer and pathology fixation on prostate biomechanics, and comparison with T 1, T 2 and ADC

NASA Astrophysics Data System (ADS)

McGrath, Deirdre M.; Lee, Jenny; Foltz, Warren D.; Samavati, Navid; van der Kwast, Theo; Jewett, Michael A. S.; Chung, Peter; Ménard, Cynthia; Brock, Kristy K.

2017-02-01

MRI is under evaluation for image-guided intervention for prostate cancer. The sensitivity and specificity of MRI parameters is determined via correlation with the gold-standard of histopathology. Whole-mount histopathology of prostatectomy specimens can be digitally registered to in vivo imaging for correlation. When biomechanical-based deformable registration is employed to account for deformation during histopathology processing, the ex vivo biomechanical properties are required. However, these properties are altered by pathology fixation, and vary with disease. Hence, this study employs magnetic resonance elastography (MRE) to measure ex vivo prostate biomechanical properties before and after fixation. A quasi-static MRE method was employed to measure high resolution maps of Young’s modulus (E) before and after fixation of canine prostate and prostatectomy specimens (n  =  4) from prostate cancer patients who had previously received radiation therapy. For comparison, T 1, T 2 and apparent diffusion coefficient (ADC) were measured in parallel. E (kPa) varied across clinical anatomy and for histopathology-identified tumor: peripheral zone: 99(±22), central gland: 48(±37), tumor: 85(±53), and increased consistently with fixation (factor of 11  ±  5 p  <  0.02). T 2 decreased consistently with fixation, while changes in T 1 and ADC were more complex and inconsistent. The biomechanics of the clinical prostate specimens varied greatly with fixation, and to a lesser extent with disease and anatomy. The data obtained will improve the precision of prostate pathology correlation, leading to more accurate disease detection and targeting.

Evaluating Effects of Divided Hemispheric Processing on Word Recognition in Foveal and Extrafoveal Displays: The Evidence from Arabic

PubMed Central

Almabruk, Abubaker A. A.; Paterson, Kevin B.; McGowan, Victoria; Jordan, Timothy R.

2011-01-01

Background Previous studies have claimed that a precise split at the vertical midline of each fovea causes all words to the left and right of fixation to project to the opposite, contralateral hemisphere, and this division in hemispheric processing has considerable consequences for foveal word recognition. However, research in this area is dominated by the use of stimuli from Latinate languages, which may induce specific effects on performance. Consequently, we report two experiments using stimuli from a fundamentally different, non-Latinate language (Arabic) that offers an alternative way of revealing effects of split-foveal processing, if they exist. Methods and Findings Words (and pseudowords) were presented to the left or right of fixation, either close to fixation and entirely within foveal vision, or further from fixation and entirely within extrafoveal vision. Fixation location and stimulus presentations were carefully controlled using an eye-tracker linked to a fixation-contingent display. To assess word recognition, Experiment 1 used the Reicher-Wheeler task and Experiment 2 used the lexical decision task. Results Performance in both experiments indicated a functional division in hemispheric processing for words in extrafoveal locations (in recognition accuracy in Experiment 1 and in reaction times and error rates in Experiment 2) but no such division for words in foveal locations. Conclusions These findings from a non-Latinate language provide new evidence that although a functional division in hemispheric processing exists for word recognition outside the fovea, this division does not extend up to the point of fixation. Some implications for word recognition and reading are discussed. PMID:21559084

An indigenous method for closed reduction of pediatric mandibular parasymphysis fracture.

PubMed

Kumar, Naresh; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal

2015-01-01

Mandibular fractures in children are very rare as compared to adults due to protected anatomic features of child and less exposure to road traffic accidents. Management becomes complicated due to inherent dynamic nature, instability of mixed dentition and fear of surgery. Conservative management can be done with the help of acrylic cap splints along with circum-mandibular wiring, intermaxillary fixation with eyelet wires, arch wires or open reduction and internal fixation with bio-resorbable plates. Different methods have various pros and cons. The choice of anesthesia is also very crucial sometimes. This case report describes a new method of closed reduction with 18 gauge needle simulated as an arch bar performed under local anaesthesia.

An indigenous method for closed reduction of pediatric mandibular parasymphysis fracture

PubMed Central

Kumar, Naresh; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal

2015-01-01

Mandibular fractures in children are very rare as compared to adults due to protected anatomic features of child and less exposure to road traffic accidents. Management becomes complicated due to inherent dynamic nature, instability of mixed dentition and fear of surgery. Conservative management can be done with the help of acrylic cap splints along with circum-mandibular wiring, intermaxillary fixation with eyelet wires, arch wires or open reduction and internal fixation with bio-resorbable plates. Different methods have various pros and cons. The choice of anesthesia is also very crucial sometimes. This case report describes a new method of closed reduction with 18 gauge needle simulated as an arch bar performed under local anaesthesia. PMID:27390498

Articulated distraction.

PubMed

Hosny, Gamal Ahmed

2011-07-01

Articular hip distraction can be applied either by using a monolateral articulated distractor or a circular fixator. The fixator should be aligned such that its axis is aligned with the transverse axis of the hip joint. Following distraction, the range of motion is maintained with regular physiotherapy. It is a useful salvage procedure in older children with hip stiffness, when other methods of containment are not applicable. Copyright © 2011 Elsevier Inc. All rights reserved.

Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy.

PubMed

Dobbe, J G G; Vroemen, J C; Strackee, S D; Streekstra, G J

2014-11-01

Preoperative three-dimensional planning methods have been described extensively. However, transferring the virtual plan to the patient is often challenging. In this report, we describe the management of a severely malunited distal radius fracture using a patient-specific plate for accurate spatial positioning and fixation. Twenty months postoperatively the patient shows almost painless reconstruction and a nearly normal range of motion.

RELATIONSHIP BETWEEN RIGIDITY OF EXTERNAL FIXATOR AND NUMBER OF PINS: COMPUTER ANALYSIS USING FINITE ELEMENTS

PubMed Central

Sternick, Marcelo Back; Dallacosta, Darlan; Bento, Daniela Águida; do Reis, Marcelo Lemos

2015-01-01

Objective: To analyze the rigidity of a platform-type external fixator assembly, according to different numbers of pins on each clamp. Methods: Computer simulation on a large-sized Cromus dynamic external fixator (Baumer SA) was performed using a finite element method, in accordance with the standard ASTM F1541. The models were generated with approximately 450,000 quadratic tetrahedral elements. Assemblies with two, three and four Schanz pins of 5.5 mm in diameter in each clamp were compared. Every model was subjected to a maximum force of 200 N, divided into 10 sub-steps. For the components, the behavior of the material was assumed to be linear, elastic, isotropic and homogeneous. For each model, the rigidity of the assembly and the Von Mises stress distribution were evaluated. Results: The rigidity of the system was 307.6 N/mm for two pins, 369.0 N/mm for three and 437.9 N/mm for four. Conclusion: The results showed that four Schanz pins in each clamp promoted rigidity that was 19% greater than in the configuration with three pins and 42% greater than with two pins. Higher tension occurred in configurations with fewer pins. In the models analyzed, the maximum tension occurred on the surface of the pin, close to the fixation area. PMID:27047879

Experimental investigations of pupil accommodation factors.

PubMed

Lee, Eui Chul; Lee, Ji Woo; Park, Kang Ryoung

2011-08-17

PURPOSE. The contraction and dilation of the iris muscle that controls the amount of light entering the retina causes pupil accommodation. In this study, experiments were performed and two of the three factors that influence pupil accommodation were analyzed: lighting conditions and depth fixations. The psychological benefits were not examined, because they could not be quantified. METHODS. A head-wearable eyeglasses-based, eye-capturing device was designed to measure pupil size. It included a near-infrared (NIR) camera and an NIR light-emitting diode. Twenty-four subjects watched two-dimensional (2D) and three-dimensional (3D) stereoscopic videos of the same content, and the changes in pupil size were measured by using the eye-capturing device and image-processing methods: RESULTS. The pupil size changed with the intensity of the videos and the disparities between the left and right images of a 3D stereoscopic video. There was correlation between the pupil size and average intensity. The pupil diameter could be estimated as being contracted from approximately 5.96 to 4.25 mm as the intensity varied from 0 to 255. Further, from the changes in the depth fixation for the pupil accommodation, it was confirmed that the depth fixation also affected accommodation of pupil size. CONCLUSIONS. It was confirmed that the lighting condition was an even more significant factor in pupil accommodation than was depth fixation (significance ratio: approximately 3.2:1) when watching 3D stereoscopic video. Pupil accommodation was more affected by depth fixation in the real world than was the binocular convergence in the 3D stereoscopic display.

An Alternative Method of Intermaxillary Fixation for Simple Pediatric Mandible Fractures.

PubMed

Farber, Scott J; Nguyen, Dennis C; Harvey, Alan A; Patel, Kamlesh B

2016-03-01

Mandibular fractures represent a substantial portion of facial fractures in the pediatric population. Pediatric mandibles differ from their adult counterparts in the presence of mixed dentition. Avoidance of injury to developing tooth follicles is critical. Simple mandibular fractures can be treated with intermaxillary fixation (IMF) using arch bars or bone screws. This report describes an alternative to these methods using silk sutures and an algorithm to assist in treating simple mandibular fractures in the pediatric population. A retrospective chart review was performed and the records of 1 surgeon were examined. Pediatric patients who underwent treatment for a mandibular fracture in the operating room from 2011 to 2015 were identified using Common Procedural Terminology codes. Data collected included age, gender, type of fracture, type of treatment used, duration of fixation, and presence of complications. Five patients with a mean age of 6.8 years at presentation were identified. Fracture types were unilateral fractures of the condylar neck (n = 3), bilateral fractures of the condylar head (n = 1), and a unilateral fracture of the condylar head with an associated parasymphyseal fracture (n = 1). IMF was performed in 4 patients using silk sutures, and bone screw fixation was performed in the other patient. No post-treatment complications or malocclusion were reported. Average duration of IMF was 18.5 days. An algorithm is presented to assist in the treatment of pediatric mandibular fractures. Silk suture fixation is a viable and safe alternative to arch bars or bone screws for routine mandibular fractures. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Clavicle Malunions: Surgical Treatment and Outcome-a Literature Review.

PubMed

Sidler-Maier, Claudia Christine; Dedy, Nicolas J; Schemitsch, Emil H; McKee, Michael D

2018-02-01

Successful treatment of clavicle malunion represents a major challenge for orthopedic surgeons. The aim of this study was to provide an overview of surgical options for the treatment of clavicle malunions regarding their technical details and clinical results. A comprehensive search of the literature was performed to retrieve articles and conference abstracts regarding the surgical treatment of clavicle malunions. A total of 1873 records were identified and 29 studies were included in the present review, with a total of 103 patients. The majority of the patients (77/103) were treated with an osteotomy and subsequent open reduction internal fixation (ORIF). The next most frequent management choice was debridement, excision, or removal of excess callus or bone ( n  = 19), but other techniques like resection of the clavicle ( n  = 5) or nerve exploration and decompression ( n  = 2) were also reported. The preferred method of fixation was plate fixation ( n  = 53) followed by pin fixation ( n  = 6). The complication rate was low, reported in less than 6% of patients. All of the currently reported surgical techniques to manage symptomatic clavicle malunion have resulted in good clinical outcomes with a low complication rate. Considering biomechanical aspects, correction osteotomy followed by plate fixation seems to be the preferred method. Further studies are needed to compare the various surgical techniques and their specific outcomes in a prospective manner. Nevertheless, this review article can be used as an overview to help choose an optimal operative treatment for patients presenting with a clavicle malunion.

Fixation of zygomatic and mandibular fractures with biodegradable plates

PubMed Central

Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

2013-01-01

Context: In this prospective study, 13 randomly selected patients underwent treatment for zygomatic–complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. Materials and Methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy's principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates. Statistical Analysis Used: Descriptives, Frequencies, and Chi-square test were used. Results: In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection. Conclusions: Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome. PMID:23662255

Primary Retrograde Tibiotalocalcaneal Nailing For Fragility Ankle Fractures

PubMed Central

Taylor, Benjamin C.; Hansen, Dane C.; Harrison, Ryan; Lucas, Douglas E; Degenova, Daniel

2016-01-01

Background Ankle fragility fractures are difficult to treat due to poor bone quality and soft tissues as well as the near ubiquitous presence of comorbidities including diabetes mellitus and peripheral neuropathy. Conventional open reduction and internal fixation in this population has been shown to lead to a significant rate of complications. Given the high rate of complications with contemporary fixation methods, the present study aims to critically evaluate the use of acute hindfoot nailing as a percutaneous fixation technique for high-risk ankle fragility fractures. Methods In this study, we retrospectively evaluated 31 patients treated with primary retrograde tibiotalocalcaneal nail without joint preparation for a mean of 13.6 months postoperatively from an urban Level I trauma center during the years 2006-2012. Results Overall, there were two superficial infections (6.5%) and three deep infections (9.7%) in the series. There were 28 (90.3%) patients that went on to radiographic union at a mean of 22.2 weeks with maintenance of foot and ankle alignment. There were three cases of asymptomatic screw breakage observed at a mean of 18.3 months postoperatively, which were all treated conservatively.. Conclusions This study shows that retrograde hindfoot nailing is an acceptable treatment option for treatment of ankle fragility fractures. Hindfoot nailing allows early weightbearing, limited soft tissue injury, and a relatively low rate of complications, all of which are advantages to conventional open reduction internal fixation techniques. Given these findings, larger prospective randomized trials comparing this treatment with conventional open reduction internal fixation techniques are warranted. PMID:27528840

Acromioclavicular Joint Fixation Using an Acroplate Combined With a Coracoclavicular Screw

PubMed Central

Tavakoli Darestani, Reza; Ghaffari, Arash; Hosseinpour, Mehrdad

2013-01-01

Background Appropriate treatment of acromioclavicular joint dislocation is controversial. Acroplate fixation is one of the most common treatment methods of acromioclavicular joint (ACJ) dislocation. Based on the risk of re-dislocation after Acroplate fixation, we assumed that combined fixation with an Acroplate and a coracoclavicular screw helps improve the outcome. Objectives The main purpose of the current study was to compare the outcome of ACJ dislocation treated with an Acroplate alone and in combination with coracoclavicular screw. Patients and Methods This study was carried out on 40 patients with ACJ dislocation types III to VI who were divided randomly into two equal groups: Acroplate group (P) and Acroplate in combination with coracoclavicular screw group (P + S). The screws were extracted 3-6 months postoperatively. The patients were followed for 1 year and Imatani’s score was calculated. Finally, the data were compared between the groups. Results The mean Imatani’s score was significantly higher in P + S group (83.4 ± 14.1) than P group (81.2 ± 10.3) (P < 0.001). The mean duration of surgery was the same in the two groups (59.8 ± 9.4 minutes in group P V.s 64.3 ± 10.9 minutes in group P + S; P = 0.169). There were no cases of re-dislocation, degenerative changes and ossification and all patients returned to their previous jobs or sporting activities. Conclusions Using a coracoclavicular screw combined with an Acroplate can improve the patients’ function after ACJ disruption without any significant increase in surgical duration. Authors recommend this technique in the fixation of ACJ dislocation. PMID:24396788

Comparison of intramedullary nailing and external fixation knee arthrodesis for the infected knee replacement.

PubMed

Mabry, Tad M; Jacofsky, David J; Haidukewych, George J; Hanssen, Arlen D

2007-11-01

We analyzed knee arthrodesis for the infected total knee replacement (TKR) using two different fixation techniques. Patients undergoing knee arthrodesis for infected TKR were identified and rates of successful fusion and recurrence of infection were compared using Cox proportional hazard models. Eighty-five consecutive patients who underwent knee arthrodesis were followed until union, nonunion, amputation, or death. External fixation achieved successful fusion in 41 of 61 patients and was associated with a 4.9% rate of deep infection. Fusion was successful in 23 of 24 patients with intramedullary (IM) nailing and was associated with an 8.3% rate of deep infection. We observed similar fusion and infection rates with the two techniques. Thirty-four patients (40%) had complications. Knee arthrodesis remains a reasonable salvage alternative for the difficult infected TKR. Complication rates are high irrespective of the technique, and one must consider the risks of both nonunion and infection when choosing the fixation method in this setting. IM nailing appears to have a higher rate of successful union but a higher risk of recurrent infection when compared with external fixation knee arthrodesis. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

[Biodegradable fixation systems in pediatric craniofacial surgery: 10-year experience with 324 patients].

PubMed

Yasonov, S A; Lopatin, A V; Bel'chenko, V A; Vasil'ev, I G

Over the past 15 years, resorbable materials have been successfully used for osteosynthesis, but their high cost prevents widespread application. However, the use of resorbable systems could be a method of choice, especially in treatment of children in the active growth period. Obviously, biodegradable materials not only are highly competitive with known metal constructs in terms of fixation rigidity, biocompatibility, and a low risk of infection but also have an undeniable advantage, such as gradual resorption allowing quick return of damaged bones to the physiological conditions of functioning. A special feature of bioresorbable systems is that they can be assembled using ultrasonic welding, which greatly facilitates the fixation process and also provides necessary rigidity, even in cases of joining very thin bones when reliable fixation with screws is impossible. Over the past 10 years, we have used biodegradable systems in 324 patients. In 244 of them, we used traditional (plate/screw) systems; in 80 cases, an ultrasonic welding system was chosen for osteosynthesis. In the present work, we discuss, based on clinical evidence, the advantages and disadvantages of both fixation systems for reconstructive craniofacial surgery in children.

[Treatment of conmminuted patellar fractures with internal Ni-Ti patellar concentrator and tension bind wire fixation].

PubMed

Tan, Hong-lie; Qian, Chen; Zhao, Jin-kun; Shi, Yan; Zhou, Qi

2009-02-01

To study the clinical efficacy of the treatment of comminuted patellar fractures with internal NiTi-Patellar concentrator and tension bind wire fixation. From March 2004 to June 2007, 38 cases of fresh comminuted patellar fractures were treated with internal NiTi-Patellar concentrator and tension bind wire fixation. There were 25 males and 13 females,ranging from 21 to 64 years (mean 42.5 years). All were comminuted fractures with displacement, 16 cases were 3 fragments, 14 cases were 4 fragments, 8 cases were 5 fragments. There were other fractures in 8 cases. During followed-up, knee function and complications were evaluated. All patients were followed up for 8 to 24 months (mean 15 months) and obtained complete bone union. No case of implant was loosening and fragment displacement, traumatic arthritis occured in 2 cases. Under Lysholm & Gillquist score, the results were excellent in 17 cases, good in 19, fair in 2. Internal Ni-Ti-Patellar concentrator and tension bind wire fixation is one of the ideal methods for the treatment of comminuted patellar fracture, which could provide satisfied reduction, reliable fixation and good functional recovery.

Fast and asymptotic computation of the fixation probability for Moran processes on graphs.

PubMed

Alcalde Cuesta, F; González Sequeiros, P; Lozano Rojo, Á

2015-03-01

Evolutionary dynamics has been classically studied for homogeneous populations, but now there is a growing interest in the non-homogeneous case. One of the most important models has been proposed in Lieberman et al. (2005), adapting to a weighted directed graph the process described in Moran (1958). The Markov chain associated with the graph can be modified by erasing all non-trivial loops in its state space, obtaining the so-called Embedded Markov chain (EMC). The fixation probability remains unchanged, but the expected time to absorption (fixation or extinction) is reduced. In this paper, we shall use this idea to compute asymptotically the average fixation probability for complete bipartite graphs K(n,m). To this end, we firstly review some recent results on evolutionary dynamics on graphs trying to clarify some points. We also revisit the 'Star Theorem' proved in Lieberman et al. (2005) for the star graphs K(1,m). Theoretically, EMC techniques allow fast computation of the fixation probability, but in practice this is not always true. Thus, in the last part of the paper, we compare this algorithm with the standard Monte Carlo method for some kind of complex networks. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Ultraviolet Light Enhances the Bovine Serum Albumin Fixation for Acid Fast Bacilli Stain

PubMed Central

Lai, Pei-Yin; Lee, Shih-Yi; Chou, Yu-Ching; Fu, Yung-Chieh; Wu, Chen-Cheng; Chiueh, Tzong-Shi

2014-01-01

The use of a liquid culture system such as MGIT broth has greatly improved the sensitivity of isolating mycobacteria in clinical laboratories. Microscopic visualization of acid fast bacilli (AFB) in the culture positive MGIT broth remains the first routine step for rapidly indicating the presence of mycobacteria. We modified an ultraviolet (UV) light fixation process to increase AFB cells adherence to the slide. The retained haze proportion of a 1-cm circle marked area on the smear slide was quantified after the staining procedure indicating the adherence degree of AFB cells. More AFB cells were preserved on the slide after exposure to UV light of either germicidal lamp or UV crosslinker in a time-dependent manner. We demonstrated both the bovine serum albumin (BSA) in MGIT media and UV light exposure were required for enhancing fixation of AFB cells. While applying to AFB stains for 302 AFB positive MGIT broths in clinics, more AFB cells were retained and observed on smear slides prepared by the modified fixation procedure rather than by the conventional method. The modified fixation procedure was thus recommended for improving the sensitivity of microscopic diagnosis of AFB cells in culture positive MGIT broth. PMID:24586725

Functional outcome of Schatzker type V and VI tibial plateau fractures treated with dual plates

PubMed Central

Prasad, G Thiruvengita; Kumar, T Suresh; Kumar, R Krishna; Murthy, Ganapathy K; Sundaram, Nandkumar

2013-01-01

Background: Dual plate fixation in comminuted bicondylar tibial plateau fractures remains controversial. Open reduction and internal fixation, specifically through compromised soft tissues, has historically been associated with major wound complications. Alternate methods of treatment have been described, each with its own merits and demerits. We performed a retrospective study to evaluate the functional outcome of lateral and medial plate fixation of Schatzker type V and VI fractures through an anterolateral approach, and a medial minimally invasive approach or a posteromedial approach. Materials and Methods: We treated 46 tibial plateau fractures Schatzker type V and VI with lateral and medial plates through an anterolateral approach and a medial minimal invasive approach over an 8 years period. Six patients were lost to followup. Radiographs in two planes were taken in all cases. Immediate postoperative radiographs were assessed for quality of reduction and fixation. The functional outcome was evaluated according to the Oxford Knee Score criteria on followup. Results: Forty patients (33 men and 7 women) who completed the followup were included in the study. There were 20 Schatzker type V fractures and 20 Schatzker type VI fractures. The mean duration of followup was 4 years (range 1-8 years). All patients had a satisfactory articular reduction defined as ≤2 mm step-off or gap as assessed on followup. All patients had a good coronal and sagittal plane alignment, and articular width as assessed on supine X-rays of the knee in the anteroposterior (AP) and lateral views. The functional outcome, as assessed by the Oxford Knee Score, was excellent in 30 patients and good in 10 patients. All patients returned to their pre-injury level of activity and employment. There were no instances of deep infection. Conclusions: Dual plate fixation of severe bicondylar tibial plateau fractures is an excellent treatment option as it provides rigid fixation and allows early knee mobilization. Careful soft tissue handling and employing minimal invasive techniques minimizes soft tissue complications. PMID:23682182

In‐loop flow [11C]CO2 fixation and radiosynthesis of N,N′‐[11C]dibenzylurea

PubMed Central

Downey, Joseph; Bongarzone, Salvatore; Hader, Stefan

2017-01-01

Cyclotron‐produced carbon‐11 is a highly valuable radionuclide for the production of positron emission tomography (PET) radiotracers. It is typically produced as relatively unreactive carbon‐11 carbon dioxide ([11C]CO2), which is most commonly converted into a more reactive precursor for synthesis of PET radiotracers. The development of [11C]CO2 fixation methods has more recently enabled the direct radiolabelling of a diverse array of structures directly from [11C]CO2, and the advantages afforded by the use of a loop‐based system used in 11C‐methylation and 11C‐carboxylation reactions inspired us to apply the [11C]CO2 fixation “in‐loop.” In this work, we developed and investigated a new ethylene tetrafluoroethylene (ETFE) loop‐based [11C]CO2 fixation method, enabling the fast and efficient, direct‐from‐cyclotron, in‐loop trapping of [11C]CO2 using mixed DBU/amine solutions. An optimised protocol was integrated into a proof‐of‐concept in‐loop flow radiosynthesis of N,N′‐[11C]dibenzylurea. This reaction exhibited an average 78% trapping efficiency and a crude radiochemical purity of 83% (determined by radio‐HPLC), giving an overall nonisolated radiochemical yield of 72% (decay‐corrected) within just 3 minutes from end of bombardment. This proof‐of‐concept reaction has demonstrated that efficient [11C]CO2 fixation can be achieved in a low‐volume (150 μL) ETFE loop and that this can be easily integrated into a rapid in‐loop flow radiosynthesis of carbon‐11–labelled products. This new in‐loop methodology will allow fast radiolabelling reactions to be performed using cheap/disposable ETFE tubing setup (ideal for good manufacturing practice production) thereby contributing to the widespread usage of [11C]CO2 trapping/fixation reactions for the production of PET radiotracers. PMID:28977686

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

PubMed

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

2017-11-01

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

In-loop flow [11 C]CO2 fixation and radiosynthesis of N,N'-[11 C]dibenzylurea.

PubMed

Downey, Joseph; Bongarzone, Salvatore; Hader, Stefan; Gee, Antony D

2018-03-01

Cyclotron-produced carbon-11 is a highly valuable radionuclide for the production of positron emission tomography (PET) radiotracers. It is typically produced as relatively unreactive carbon-11 carbon dioxide ([ 11 C]CO 2 ), which is most commonly converted into a more reactive precursor for synthesis of PET radiotracers. The development of [ 11 C]CO 2 fixation methods has more recently enabled the direct radiolabelling of a diverse array of structures directly from [ 11 C]CO 2 , and the advantages afforded by the use of a loop-based system used in 11 C-methylation and 11 C-carboxylation reactions inspired us to apply the [ 11 C]CO 2 fixation "in-loop." In this work, we developed and investigated a new ethylene tetrafluoroethylene (ETFE) loop-based [ 11 C]CO 2 fixation method, enabling the fast and efficient, direct-from-cyclotron, in-loop trapping of [ 11 C]CO 2 using mixed DBU/amine solutions. An optimised protocol was integrated into a proof-of-concept in-loop flow radiosynthesis of N,N'-[ 11 C]dibenzylurea. This reaction exhibited an average 78% trapping efficiency and a crude radiochemical purity of 83% (determined by radio-HPLC), giving an overall nonisolated radiochemical yield of 72% (decay-corrected) within just 3 minutes from end of bombardment. This proof-of-concept reaction has demonstrated that efficient [ 11 C]CO 2 fixation can be achieved in a low-volume (150 μL) ETFE loop and that this can be easily integrated into a rapid in-loop flow radiosynthesis of carbon-11-labelled products. This new in-loop methodology will allow fast radiolabelling reactions to be performed using cheap/disposable ETFE tubing setup (ideal for good manufacturing practice production) thereby contributing to the widespread usage of [ 11 C]CO 2 trapping/fixation reactions for the production of PET radiotracers. © 2017 The Authors. Journal of Labelled Compounds and Radiopharmaceuticals Published by John Wiley & Sons, Ltd.

Anterior-inferior tibiofibular ligament anatomical repair and augmentation versus trans-syndesmosis screw fixation for the syndesmotic instability in external-rotation type ankle fracture with posterior malleolus involvement: A prospective and comparative study.

PubMed

Zhan, Yu; Yan, Xiaoyu; Xia, Ronggang; Cheng, Tao; Luo, Congfeng

2016-07-01

Syndesmosis injury is common in external-rotation type ankle fractures (ERAF). Trans-syndesmosis screw fixation, the gold-standard treatment, is currently controversial for its complications and biomechanical disadvantages. The purpose of this study was to introduce a new method of anatomically repairing the anterior-inferior tibiofibular ligament (AITFL) and augmentation with anchor rope system to treat the syndesmotic instability in ERAF with posterior malleolus involvement and to compare its clinical outcomes with that of trans-syndesmosis screw fixation. 53 ERAFs with posterior malleolus involvement received surgery, and the syndesmosis was still unstable after fracture fixation. They were randomised into screw fixation group and AITFL anatomical repair with augmentation group. Reduction quality, syndesmosis diastasis recurrence, pain (VAS score), time back to work, Olerud-Molander ankle score and range of motion (ROM) of ankle were investigated. Olerud-Molander score in AITFL repair group and screw group was 90.4 and 85.8 at 12-month follow-up (P>0.05). Plantar flexion was 31.2° and 34.3° in repair and screw groups (P=0.04). Mal-reduction happened in 5 cases (19.2%) in screw group while 2 cases (7.4%) in repair group. Postoperative syndesmosis re-diastasis occurred in 3 cases in screw group while zero in repair group (P>0.05). Pain score was similar between the two groups (P>0.05). Overall complication rate and back to work time were 26.9% and 3.7% (P=0.04), 7.15 months and 5.26 months (P=0.02) in screw group and repair group, respectively. For syndesmotic instability in ERAF with posterior malleolus involvement, the method of AITFL anatomical repair and augmentation with anchor rope system had an equivalent functional outcome and reduction, earlier rehabilitation and less complication compared with screw fixation. It can be selected as an alternative. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Additively Manufactured Porous NiTi and Ti-6Al-4V in Mandibular Reconstruction: Introducing the Stiffness-Matched and the Variable Stiffness Options for the Reconstruction Plates

NASA Astrophysics Data System (ADS)

Jahadakbar, Ahmadreza

Mandibular reconstruction surgery is a part of treatment for cancer, tumor, and all the cases that involve segmental defects. One of the most common approaches for the reconstruction surgery is to resect the segmental defect and use a double barrel fibula graft to fill the resected region and recover the mandible's normal functions, such as chewing. The grafted bone is connected to the host mandible, using the standard of the care Ti-6Al-4V fixation plates. The fixation plates are available in the form of prefabricated plates and also patient-specific plates in the market. Due to the high stiffness of the Ti-6Al-4V plates in comparison with the mandible bone and the grafted bone, the loading distribution on the whole reconstructed mandible will be different from a healthy mandible. The high stiffness fixation hardware carries a great portion of the loading and causes stress shielding on the grafted bone and the surrounding host bone. Based on the bone remodeling theory, the stress shielding on the cortical bone causes bone resorption and may lead to implant failure. A solution to reduce the risk of implant failure is to use a low stiffness biocompatible material for the mandibular fixation plates. We have proposed the use of stiffness-matched, porous NiTi fixation plates either in the form of patient-specific or prefabricated, instead of the standard of the care Ti-6Al-4V plates. NiTi is a biocompatible material that has a low stiffness in comparison with Ti-6Al-4V and also benefits from the superelastic feature. Superelasticity, which can also be found in bone tissues, allows the material to recover large strains (up to 8%) and increases the shock absorption. In this thesis, we have evaluated the use of proposed fixation hardware by comparing it with a healthy mandible and a reconstructed mandible using the standard method. To this end, first different models including a healthy mandible, a reconstructed mandible using patient-specific Ti-6Al-4V fixation hardware, a reconstructed mandible using stiffness-match patient-specific hardware, and several prefabricated fixation plates were prepared. After verification of the models, the cases of reconstructed mandibles were used to simulate different periods, including during healing, and post-healing periods. Also, different loading conditions including highest bite force on the first molar tooth, rest condition, and also highest bite force on a dental implant right in the grafted bone were simulated. Also, the theory of applying pretention to the fixation plates was evaluated using the finite element method. We also designed and evaluated a set of prefabricated fixation kits with various stiffness option. After all these finite element simulations and having the CAD files of the porous fixation plates, the possibility of fabrication of the proposed hardware, in both forms of patient-specific, and prefabricated plates was evaluated using selective laser melting.

Numerical simulation of multi-dimensional NMR response in tight sandstone

NASA Astrophysics Data System (ADS)

Guo, Jiangfeng; Xie, Ranhong; Zou, Youlong; Ding, Yejiao

2016-06-01

Conventional logging methods have limitations in the evaluation of tight sandstone reservoirs. The multi-dimensional nuclear magnetic resonance (NMR) logging method has the advantage that it can simultaneously measure transverse relaxation time (T 2), longitudinal relaxation time (T 1) and diffusion coefficient (D). In this paper, we simulate NMR measurements of tight sandstone with different wettability and saturations by the random walk method and obtain the magnetization decays of Carr-Purcell-Meiboom-Gill pulse sequences with different wait times (TW) and echo spacings (TE) under a magnetic field gradient, resulting in D-T 2-T 1 maps by the multiple echo trains joint inversion method. We also study the effects of wettability, saturation, signal-to-noise ratio (SNR) of data and restricted diffusion on the D-T 2-T 1 maps in tight sandstone. The results show that with decreasing wetting fluid saturation, the surface relaxation rate of the wetting fluid gradually increases and the restricted diffusion phenomenon becomes more and more obvious, which leads to the wetting fluid signal moving along the direction of short relaxation and the direction of the diffusion coefficient decreasing in D-T 2-T 1 maps. Meanwhile, the non-wetting fluid position in D-T 2-T 1 maps does not change with saturation variation. With decreasing SNR, the ability to identify water and oil signals based on NMR maps gradually decreases. The wetting fluid D-T 1 and D-T 2 correlations in NMR diffusion-relaxation maps of tight sandstone are obtained through expanding the wetting fluid restricted diffusion models, and are further applied to recognize the wetting fluid in simulated D-T 2 maps and D-T 1 maps.

Metal matrix coated fiber composites and the methods of manufacturing such composites

DOEpatents

Weeks, Jr., Joseph K.; Gensse, Chantal

1993-01-01

A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials.

Metal matrix coated fiber composites and the methods of manufacturing such composites

DOEpatents

Weeks, J.K. Jr.; Gensse, C.

1993-09-14

A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials. 8 figures.

Analysis of formalin-fixed, paraffin-embedded (FFPE) tissue via proteomic techniques and misconceptions of antigen retrieval.

PubMed

O'Rourke, Matthew B; Padula, Matthew P

2016-01-01

Since emerging in the late 19(th) century, formaldehyde fixation has become a standard method for preservation of tissues from clinical samples. The advantage of formaldehyde fixation is that fixed tissues can be stored at room temperature for decades without concern for degradation. This has led to the generation of huge tissue banks containing thousands of clinically significant samples. Here we review techniques for proteomic analysis of formalin-fixed, paraffin-embedded (FFPE) tissue samples with a specific focus on the methods used to extract and break formaldehyde crosslinks. We also discuss an error-of-interpretation associated with the technique known as "antigen retrieval." We have discovered that this term has been mistakenly applied to two disparate molecular techniques; therefore, we argue that a terminology change is needed to ensure accurate reporting of experimental results. Finally, we suggest that more investigation is required to fully understand the process of formaldehyde fixation and its subsequent reversal.

Water-use advantage for lianas over trees in tropical seasonal forests.

PubMed

Chen, Ya-Jun; Cao, Kun-Fang; Schnitzer, Stefan A; Fan, Ze-Xin; Zhang, Jiao-Lin; Bongers, Frans

2015-01-01

Lianas exhibit peak abundance in tropical forests with strong seasonal droughts, the eco-physiological mechanisms associated with lianas coping with water deficits are poorly understood. We examined soil water partitioning, sap flow, and canopy eco-physiological properties for 99 individuals of 15 liana and 34 co-occurring tree species in three tropical forests that differed in soil water availability. In the dry season, lianas used a higher proportion of deep soil water in the karst forest (KF; an area with severe seasonal soil water deficit (SSWD)) and in the tropical seasonal forest (TSF, moderate SSWD), permitting them to maintain a comparable leaf water status than trees in the TSF or a better status than trees in the KF. Lianas exhibited strong stomatal control to maximize carbon fixation while minimizing dry season water loss. During the dry period, lianas significantly decreased water consumption in the TSF and the KF. Additionally, lianas had a much higher maximum photosynthetic rates and sap flux density in the wet season and a lower proportional decline in photosynthesis in the dry season compared with those of trees. Our results indicated that access to deep soil water and strong physiological adjustments in the dry season together with active wet-season photosynthesis may explain the high abundance of lianas in seasonally dry forests. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Healing at the interface between recipient sites and autologous block bone grafts affixed by either position or lag screw methods: a histomorphometric study in rabbits.

PubMed

Caneva, Marco; Botticelli, Daniele; Carneiro Martins, Evandro Neto; Caneva, Martina; Lang, Niklaus P; Xavier, Samuel P

2017-12-01

To compare the sequential healing at the interface gap occurring between autologous bone grafts and recipient sites using two types of fixation techniques. Twenty-four adult male New Zealand white rabbits were used. Two bone grafts were collected from the calvaria and secured to the lateral aspect of the angle of mandible in each animal. Cortical perforations at the recipient sites were performed. However, no modifications were applied to the graft for its adaptation to the recipient site. Two types of fixation techniques by position or lag screws were applied. This was done by preparing osteotomy holes smaller or larger than the screw diameter, respectively. The animals were sacrificed after 3, 7, 20, and 40 days. After 3 days, the distance between the graft and the recipient site was similar between the two different fixations. Due to the anatomical shapes of the recipient sites and grafts, the distance between the two parts was lower in the central region (<0.1 mm) compared to the external regions of the graft (0.5-0.6 mm). The first evidence of small amounts of new (woven) bone was seen after 7 days, forming from the parent bone. The percentage increased after 20 and 40 days. After 40 days, the grafts were well incorporated within the recipient sites in both groups without any statistically significant difference. The present study did not show superiority of one method over another. A fixation to a recipient site with perforations may be sufficient for incorporating an autologous bone graft even if its adaptation is not perfect and irrespectively of the fixation method. Distances of approximately half millimeter were bridged with newly formed bone. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of Low-Dose Microwave on Healing of Fractures with Titanium Alloy Internal Fixation: An Experimental Study in a Rabbit Model

PubMed Central

Zhang, Han; Fu, Tengfei; Jiang, Lan; Bai, Yuehong

2013-01-01

Background Microwave is a method for improving fracture repair. However, one of the contraindications for microwave treatment listed in the literature is surgically implanted metal plates in the treatment field. The reason is that the reflection of electromagnetic waves and the eddy current stimulated by microwave would increase the temperature of magnetic implants and cause heat damage in tissues. Comparing with traditional medical stainless steel, titanium alloy is a kind of medical implants with low magnetic permeability and electric conductivity. But the effects of microwave treatment on fracture with titanium alloy internal fixation in vivo were not reported. The aim of this article was to evaluate the security and effects of microwave on healing of a fracture with titanium alloy internal fixation. Methods Titanium alloy internal fixation systems were implanted in New Zealand rabbits with a 3.0 mm bone defect in the middle of femur. We applied a 30-day microwave treatment (2,450MHz, 25W, 10 min per day) to the fracture 3 days after operation. Temperature changes of muscle tissues around implants were measured during the irradiation. Normalized radiographic density of the fracture gap was measured on the 10th day and 30th day of the microwave treatment. All of the animals were killed after 10 and 30 days microwave treatment with histologic and histomorphometric examinations performed on the harvested tissues. Findings The temperatures did not increase significantly in animals with titanium alloy implants. The security of microwave treatment was also supported by histology of muscles, nerve and bone around the implants. Radiographic assessment, histologic and histomorphometric examinations revealed significant improvement in the healing bone. Conclusion Our results suggest that, in the healing of fracture with titanium alloy internal fixation, a low dose of microwave treatment may be a promising method. PMID:24086626

Effect of Fixatives and Tissue Processing on the Content and Integrity of Nucleic Acids

PubMed Central

Srinivasan, Mythily; Sedmak, Daniel; Jewell, Scott

2002-01-01

Clinical and molecular medicines are undergoing a revolution based on the accelerated advances in biotechnology such as DNA microarrays and proteomics. Answers to fundamental questions such as how does the DNA sequence differ between individuals and what makes one individual more prone for a certain disease are eagerly being sought in this postgenomic era. Several government and nonprofit organizations provide the researchers access to human tissues for molecular studies. The tissues procured by the different organizations may differ with respect to fixation and processing parameters that may affect significantly the molecular profile of the tissues. It is imperative that a prospective investigator be aware of the potential contributing factors before designing a project. The purpose of this review is to provide an overview of the methods of human tissue acquisition, fixation, and preservation. In addition, the parameters of procurement and fixation that affect the quality of the tissues at the molecular level are discussed. PMID:12466110

[Three-dimensional Finite Element Analysis to T-shaped Fracture of Pelvis in Sitting Position].

PubMed

Fan, Yanping; Lei, Jianyin; Liu, Haibo; Li, Zhiqiang; Cai, Xianhua; Chen, Weiyi

2015-10-01

We developed a three-dimensional finite element model of the pelvis. According to Letournel methods, we established a pelvis model of T-shaped fracture with its three different fixation systems, i. e. double column reconstruction plates, anterior column plate combined with posterior column screws and anterior column plate combined with quadrilateral area screws. It was found that the pelvic model was effective and could be used to simulate the mechanical behavior of the pelvis. Three fixation systems had great therapeutic effect on the T-shaped fracture. All fixation systems could increase the stiffness of the model, decrease the stress concentration level and decrease the displacement difference along the fracture line. The quadrilateral area screws, which were drilled into cortical bone, could generate beneficial effect on the T-type fracture. Therefore, the third fixation system mentioned above (i. e. the anterior column plate combined with quadrilateral area screws) has the best biomechanical stability to the T-type fracture.

Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions.

PubMed

Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

2010-05-07

Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient's body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. In most cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy.

Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions

PubMed Central

Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

2010-01-01

Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient’s body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. Inmost cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy. PMID:20371908

76 FR 60372 - Application for Annuity or Lump Sum

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-29

... regulations to allow alternative signature methods in addition to the traditional pen-and-ink or ``wet... to allow signature alternatives to the traditional pen-and-ink (``wet'') signature. The Board changes... the agency. The second alternate method is referred to as an ``alternative signature'' or ``signature...

Recent developments of the in situ wet cell technology for transmission electron microscopies.

PubMed

Chen, Xin; Li, Chang; Cao, Hongling

2015-03-21

In situ wet cells for transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) allow studying structures and processes in a liquid environment with high temporal and spatial resolutions, and have been attracting increasing research interests in many fields. In this review, we highlight the structural and functional developments of the wet cells for TEM and STEM. One of the key features of the wet cells is the sealing technique used to isolate the liquid sample from the TEM/STEM vacuum environments, thus the existing in situ wet cells are grouped by different sealing methods. In this study, the advantages and shortcomings of each type of in situ wet cells are discussed, the functional developments of different wet cells are presented, and the future trends of the wet cell technology are addressed. It is suggested that in the future the in situ wet cell TEM/STEM technology will have an increasing impact on frontier nanoscale research.

Microtubules in Plant Cells: Strategies and Methods for Immunofluorescence, Transmission Electron Microscopy and Live Cell Imaging

PubMed Central

Celler, Katherine; Fujita, Miki; Kawamura, Eiko; Ambrose, Chris; Herburger, Klaus; Wasteneys, Geoffrey O.

2016-01-01

Microtubules are required throughout plant development for a wide variety of processes, and different strategies have evolved to visualize and analyze them. This chapter provides specific methods that can be used to analyze microtubule organization and dynamic properties in plant systems and summarizes the advantages and limitations for each technique. We outline basic methods for preparing samples for immunofluorescence labelling, including an enzyme-based permeabilization method, and a freeze-shattering method, which generates microfractures in the cell wall to provide antibodies access to cells in cuticle-laden aerial organs such as leaves. We discuss current options for live cell imaging of MTs with fluorescently tagged proteins (FPs), and provide chemical fixation, high pressure freezing/freeze substitution, and post-fixation staining protocols for preserving MTs for transmission electron microscopy and tomography. PMID:26498784

Bacteria on External Fixators: Which Prep is Best?

DTIC Science & Technology

2012-01-01

aureus (lux). After 12 hours in the broth, a sufficient time to allow biofilm formation ,11 the constructs were individually removed and baseline imaging...difference when cleansing components consisting of stainless steel and alumi- num.15–17 We also found that a simulated external fixator adjustment exposed...Albert E, et al. Direct continuous method for monitoring biofilm infection in a mouse model. Infect Immun. 2003;71: 882–890. 11. Charles CA, Ricotti CA

Research perspectives in first metatarsal osteotomy and fixation stability.

PubMed

Landsman, A S; Higgins, K R; Lampe, N

1996-07-01

Well-designated research is required to provide clinical guidance by validation of old and new methods. Variables, including technologic advancement in surgical techniques, diagnosis, shoe design, and immobilization all contribute to the challenge of investigating surgical procedures of the foot. This article highlights some of the relevant research pertaining to first metatarsal osteotomies and internal fixation and provides direction for potential, future research. Numerous aspects about the research techniques involved are discussed.

Neurally and Ocularly Informed Graph-Based Models for Searching 3D Environments

DTIC Science & Technology

2014-06-03

hBCI = hybrid brain–computer interface, TAG = transductive annotation by graph, CV = computer vision, TSP = traveling salesman problem . are navigated...environment that are most likely to contain objects that the subject would like to visit. 2.9. Route planning A traveling salesman problem (TSP) solver...fixations in a visual search task using fixation-related potentials J. Vis. 13 Croes G 1958 A method for solving traveling - salesman problems Oper. Res

Budgets of fixed nitrogen in the Orinoco Savannah Region: Role of pyrodenitrification

NASA Astrophysics Data System (ADS)

Sanhueza, Eugenio; Crutzen, Paul J.

1998-12-01

Human activities have strongly altered the amount of fixed nitrogen that cycles in many regions of the industrialized world, with serious environmental consequences. Past studies conducted at the Orinoco savannahs of Venezuela offer a unique possibility for reviewing the cycling of nitrogen species in a tropical environment. The available information for the Orinoco savannahs is critically reviewed, and, despite many uncertainties, we present a budget analysis of both the fixed N in the soil-vegetation system and atmospheric NOy. Analysis of the data indicates that nitrogen fixation, especially by legumes, and ammonia emission from vegetation and animal wastes needs considerable attention in future research efforts. In contrast with many regions of the world, in the studied region, nonindustrial sources, foremost biomass burning, dominate the soil-vegetation and atmospheric budgets of fixed N. In general, N cycling is mainly driven by biomass burning. The resulting pyrodenitrification in the soil-vegetation system is the largest single process that, during the following wet season, may promote biological fixation to compensate for the N losses from fires during the burning season. However, a gradual impoverishment of the N status of the savannah ecosystems cannot be excluded. During the dry season, biomass burning is also the main source of atmospheric NOy, which is largely exported, mainly in the direction of the Amazon forest. Together with other nutrients, a "fertilization" of the Amazon forest due to biomass burning in the savannah may be the result. These issues require further scientific analysis.

Biodegradable screw versus a press-fit bone plug fixation for hamstring anterior cruciate ligament reconstruction: a prospective randomized study.

PubMed

Jagodzinski, Michael; Geiges, Bjoern; von Falck, Christian; Knobloch, Karsten; Haasper, Carl; Brand, Juergen; Hankemeier, Stefan; Krettek, Christian; Meller, Rupert

2010-03-01

Press-fit fixation of a tendon graft has been advocated to achieve tendon-to-bone healing. Fixation of hamstring tendon grafts with a porous bone scaffold limits bone tunnel enlargement compared with a biodegradable interference screw fixation. Randomized controlled trial; Level of evidence, 1. Methods Between 2005 and 2006, 20 patients (17 men, 3 women) with a primary reconstruction of the anterior cruciate ligament (ACL) were enrolled in this study. Patients were randomized to obtain graft fixation in the tibial tunnel either by means of an interference screw (I) or a press-fit fixation with a porous bone cylinder (P). At 3 months after surgery, a computed tomography (CT) scan of the knee was performed, and tunnel enlargement was analyzed in the coronal and sagittal planes for the proximal, middle, and distal thirds of the tunnel. After 6 months and 1 and 2 years, radiographs of the knee in the sagittal and coronal plane were analyzed for bone tunnel widening. The International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores of both groups were compared after 1 and 2 years. The bone tunnel enlargement determined by CT was 106.9% + or - 10.9% for group P and 121.9% + or - 9.0% for group I (P < .02) in the anteroposterior (AP) plane and 102.8% + or - 15.2% versus 121.5% + or - 10.1% in the coronal plane (P <.01). The IKDC, Tegner, and Lysholm scores improved in both groups from preoperatively to postoperatively without significant differences between the 2 groups. There was a trend to higher knee stability in group P after 3 months (0.6 + or - 1.4 mm vs 1.8 + or - 1.5 mm; P = .08). Both interference screw and a press-fit fixation lead to a high number of good or very good outcomes after ACL reconstruction. Tibial press-fit fixation decreases the amount of proximal bone tunnel enlargement.

The emergence and early evolution of biological carbon-fixation.

PubMed

Braakman, Rogier; Smith, Eric

2012-01-01

The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology, making it more plausible than any modern pathway as a primitive universal ancestral form.

Comparison of inhibition of N2 fixation and ureide accumulation under water deficit in four common bean genotypes of contrasting drought tolerance

PubMed Central

Coleto, I.; Pineda, M.; Rodiño, A. P.; De Ron, A. M.; Alamillo, J. M.

2014-01-01

Background and Aims Drought is the principal constraint on world production of legume crops. There is considerable variability among genotypes in sensitivity of nitrogen fixation to drought, which has been related to accumulation of ureides in soybean. The aim of this study was to search for genotypic differences in drought sensitivity and ureide accumulation in common bean (Phaseolus vulgaris) germplasm that may be useful in the improvement of tolerance to water deficit in common bean. Methods Changes in response to water deficit of nitrogen fixation rates, ureide content and the expression and activity of key enzymes for ureide metabolism were measured in four P. vulgaris genotypes differing in drought tolerance. Key Results A variable degree of drought-induced nitrogen fixation inhibition was found among the bean genotypes. In addition to inhibition of nitrogen fixation, there was accumulation of ureides in stems and leaves of sensitive and tolerant genotypes, although this was higher in the leaves of the most sensitive ones. In contrast, there was no accumulation of ureides in the nodules or roots of stressed plants. In addition, the level of ureides in the most sensitive genotype increased after inhibition of nitrogen fixation, suggesting that ureides originate in vegetative tissues as a response to water stress, probably mediated by the induction of allantoinase. Conclusions Variability of drought-induced inhibition of nitrogen fixation among the P. vulgaris genotypes was accompanied by subsequent accumulation of ureides in stems and leaves, but not in nodules. The results indicate that shoot ureide accumulation after prolonged exposure to drought could not be the cause of inhibition of nitrogen fixation, as has been suggested in soybean. Instead, ureides seem to be produced as part of a general response to stress, and therefore higher accumulation might correspond to higher sensitivity to the stressful conditions. PMID:24638821

The management of tibial pilon fractures with the Ilizarov fixator: The role of ankle arthroscopy.

PubMed

El-Mowafi, Hani; El-Hawary, Ahmed; Kandil, Yasser

2015-12-01

Pilon fractures usually result from high energy trauma, and are commonly associated with extensive soft tissue damage which prevents the use of open reduction and internal fixation. This study was designed to evaluate the use of the Ilizarov external fixator in the treatment of pilon fractures of the ankle, and to determine whether arthroscopy of the ankle could improve the outcome. From February 2011 to May 2013 a total of 23 patients with unilateral closed pilon fractures were divided into two groups treated with and without arthroscopy during fixation with the Ilizarov external fixator. The fractures were classified according to the AO Rüdi and Allgőwer classification. Follow up ranged from 10 to 37 months with a mean of 18 months. All cases were evaluated at follow up by the AOFAS and the Bone et al. grading system. According to Bone et al. there were 3 cases excellent, 4 cases good, 2 cases fair, and 2 cases poor in Group A (without arthroscopy), whereas there were 4 cases excellent, 6 cases good, 2 cases fair in Group B (with arthroscopy). The AOFAS score for Group A was 77.8±5.8, and for Group B was 78.4±6.9. We concluded that the Ilizarov external fixator is an excellent method in treating pilon fractures as it minimizes the need for extensive surgery. We also conclude that the use of arthroscopy during pilon fracture fixation did not add statistically significant improvement to our results and it needs longer term investigation to assess its advantage - if any - to the final outcome. level 2. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Indications for arthrodesis of the knee joint in modern orthopedics].

PubMed

Hart, R; Janecek, M; Bucek, P; Procházka, V; Visna, P

2003-04-01

Indication for arthrodesis of the knee joint is nowadays most frequently failure of a total endoprosthesis, usually septic. A less frequent indication is purulent gonitis, frequently after corticoid administration, the condition after a complicated intraarticular fracture with subsequent arthritis or oncological disease of the bones in the area of the knee joint. In the course of 2000 to 2002 at the authors' department 15 arthrodeses were implanted. In three cases the indication for arthrodesis was purulent gonitis, in three cases the condition after an open articular injury associated with infectious complications and in the remaining nine cases failure of an endoprosthesis of the knee, incl. seven caused by infection. The patients were three men and 12 women, mean age 64 years (30-75 years). For stabilization of the arthrodesis 9x external fixation was used, 5x plates and 1x intramedullary osteosynthesis. In all cases consolidation of the arthrodesis was achieved. In one case the external fixation had to be replaced by a system of two fixation devices and in one case correction of the axial position of the extremity was made. The presence of external fixation was perceived negatively in particular by female patients. Plate osteosynthesis and the use of external fixation devices are relatively quick, cheap and considerate methods of arthrodesis. External fixation must be used in acute virulent infections while plate osteosynthesis can be indicated in its absence. The characteristic of intramedullary fixation is similar, however special nails used for arthrodesis of the knee are several times more expensive than the previous types of stabilization. The advantage is the possibility to use a massive bone graft to fill the defect.

Bronchoscopic Implantation of a Novel Wireless Electromagnetic Transponder in the Canine Lung: A Feasibility Study

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

Mayse, Martin L.; Parikh, Parag J.; Lechleiter, Kristen M.

2008-09-01

Purpose: The success of targeted radiation therapy for lung cancer treatment is limited by tumor motion during breathing. A real-time, objective, nonionizing, electromagnetic localization system using implanted electromagnetic transponders has been developed (Beacon electromagnetic transponder, Calypso Medical Technologies, Inc., Seattle, WA). We evaluated the feasibility and fixation of electromagnetic transponders bronchoscopically implanted in small airways of canine lungs and compared to results using gold markers. Methods and Materials: After approval of the Animal Studies Committee, five mongrel dogs were anesthetized, intubated, and ventilated. Three transponders were inserted into the tip of a plastic catheter, passed through the working channel ofmore » a flexible bronchoscope, and implanted into small airways of a single lobe using fluoroscopic guidance. This procedure was repeated for three spherical gold markers in the opposite lung. One, 7, 14, 28, and 60 days postimplantation imaging was used to assess implant fixation. Results: Successful bronchoscopic implantation was possible for 15 of 15 transponders and 12 of 15 gold markers; 3 markers were deposited in the pleural space. Fixation at 1 day was 15 of 15 for transponders and 12 of 12 for gold markers. Fixation at 60 days was 6 of 15 for transponders and 7 of 12 for gold markers, p value = 0.45. Conclusions: Bronchoscopic implantation of both transponders and gold markers into the canine lung is feasible, but fixation rates are low. If fixation rates can be improved, implantable electromagnetic transponders may allow improved radiation therapy for lung cancer by providing real-time continuous target tracking. Developmental work is under way to improve the fixation rates and to reduce sensitivity to implantation technique.« less

The effect of double-row fixation on initial repair strength in rotator cuff repair: a biomechanical study.

PubMed

Meier, Steven W; Meier, Jeffrey D

2006-11-01

The purpose of this study was to compare the initial mechanical strength of 3 rotator cuff repair techniques. A total of 30 fresh-frozen cadaveric shoulders were prepared, and full-thickness supraspinatus tears were created. Specimens were randomized and placed into 3 groups: (1) transosseous suture technique (group I: TOS, n = 10, 6F/4M), (2) single-row suture anchor fixation (group II: SRSA, n = 10, 6F/4M), and (3) double-row suture anchor fixation (group III: DRSA, n = 10, 6F/4M). Each specimen underwent cyclic load testing from 5 N to 180 N at a rate of 33 mm/sec. The test was stopped when complete failure (repair site gap of 10 mm) or a total of 5,000 cycles was attained. Group I (TOS) failed at an average of 75.3 +/- 22.49 cycles, and group II (SRSA) at an average of 798.3 +/- 73.28 cycles; group III (DRSA) had no failures because all samples were stopped when 5,000 cycles had been completed. Fixation strength of the DRSA technique proved to be significantly greater than that of SRSA (P < .001), and both suture anchor groups were significantly stronger than the TOS group (P < .001). Suture anchor repairs were significantly stronger than transosseous repairs. Furthermore, double-row suture anchor fixation was significantly stronger than was single-row repair. Therefore, double-row fixation may be superior to other techniques in that it provides a substantially stronger repair that could lead to improved biologic healing. A high incidence of incomplete healing occurs in rotator cuff repair. Use of double-row fixation may help the clinician to address some deficiencies in current methods by increasing the strength of the repair, potentially leading to improved healing rates.

Double calcaneal osteotomy with percutaneous Steinmann pin fixation as part of treatment for flexible flatfoot deformity: a review of consecutive cases highlighting our experience with pin fixation.

PubMed

Boffeli, Troy J; Abben, Kyle W

2015-01-01

Surgical correction of flexible flatfoot deformity and posterior tibial tendon dysfunction has been extensively reported in published studies. When appropriate, calcaneal osteotomies for flatfoot correction have been a favorite of foot and ankle surgeons because of the corrective power achieved without the need to fuse any rearfoot joints. The medial displacement calcaneal osteotomy and Evans calcaneal osteotomy, together termed the double calcaneal osteotomy, have been reported several times by various investigators with a wide variety of fixation options. We undertook an institutional review board-approved retrospective review of 9 consecutive patients (11 feet), who had undergone double calcaneal osteotomy with 2 percutaneous Steinmann pin fixation for the correction of flexible flatfoot deformity, with or without posterior tibial tendon dysfunction. All patients had radiographic evidence of bone healing of the posterior calcaneal osteotomy and incorporation of the Evans osteotomy bone graft at 6 weeks and demonstrated clinical healing at 6 weeks. All patients had 2 percutaneous Steinmann pins placed through both osteotomies, and these were removed an average of 6 weeks postoperatively. No patient developed pin site complications. The only complication noted was sural neuritis, which was likely incision related. No patients had delayed union or nonunion, and we did not identify any graft shifting postoperatively. The present retrospective series highlights our experience with 2 percutaneous Steinmann pin fixation, demonstrating equal or better results than many previous published fixation methods for double calcaneal osteotomy. It is cost-effective and minimizes the potential risk of iatrogenic Achilles pathologic features associated with screw fixation. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Incidence of infection after early intramedullary nailing of open tibial shaft fractures stabilized with pinless external fixators

PubMed Central

Kulshrestha, Vikas

2008-01-01

Background: A major drawback of conventional fixator system is the penetration of fixator pins into the medullary canal. The pins create a direct link between the medullary cavity and outer environment, leading to higher infection rates on conversion to intramedullary nailing. This disadvantage is overcome by the AO pinless fixator, in which the trocar points are clamped onto the outer cortex without penetrating it. This study was designed to evaluate the role of AO pinless fixators in primary stabilization of open diaphyseal tibial fractures that received staged treatment because of delayed presentation or poor general condition. We also analyzed the rate of infection on early conversion to intramedullary nail. Materials and Methods: This study is a retrospective review of 30 open diaphyseal fractures of tibia, which were managed with primary stabilization with pinless fixator and early exchange nailing. Outcome was evaluated in terms of fracture union and rate of residual infection. The data were compared with that available in the literature. Results: All the cases were followed up for a period of 2 years. The study includes Gustilo type 1 (n=10), 14 Gustilo type 2 (n=14), and type3 (n=6) cases. 6 cases (20%) had clamp site infection, 2 cases (6.7%) had deep infection, and in 28 cases (93%) the fracture healed and consolidated well. Conclusion: This study has highlighted the valuable role of pinless external fixator in the management of open tibial fractures in terms of safety and ease of application as well as the advantage of early conversion to intramedullary implant without the risk of deep infection. PMID:19753227

Histology without formalin?

PubMed

Buesa, René J

2008-12-01

Because formalin is toxic, carcinogenic, and a poor preserver of nucleic acids, for more than 20 years, there have been numerous attempts to find a substitute, with as many different alternative fixatives, none totally successful. With a fast penetration, formaldehyde is a slow and reversible fixative that requires 24 to 48 hours to completely bind to tissue; thus, any surgical specimen arriving to the laboratory between 8 AM and 4 PM and processed conventionally for the slides to be ready the following day will be only between 30% and 66% bound and even less fixed when the dehydration starts, resulting in an additional and also incomplete alcoholic fixation. This causes infiltration problems and can affect subsequent tests, especially immunohistochemistry. Formaldehyde fixation is tissue thickness independent between 16 microm and 4 mm but is faster at above room temperature, so the fixation of specimens with less than 24 hours in formalin can be improved if the fixing stations in the conventional tissue processors are set at 40 degrees C. If the safety measures are improved to offer a work environment with a time weighted average level of 0.4 ppm, and the contact with formalin is reduced to a minimum by discouraging its neutralization and limiting the recycling practice to filtering methods, formalin could remain as the routine fixative, with modified methacarn for those specimens requiring nucleic acids studies. This is a preferred solution than having to validate all the standard and special procedures, including those US Food and Drug Administration approved, if formalin is replaced by another fixative without its advantages. To the question posed in the title of this article, the answer is "Yes, it can be done, but that is neither likely nor worth it!"

Choroidal Blood Flow Decreases with Age: An MRI Study

PubMed Central

San Emeterio Nateras, Oscar; Harrison, Joseph M.; Muir, Eric R.; Zhang, Yi; Peng, Qi; Chalfin, Steven; Gutierrez, Juan E.; Johnson, Daniel A.; Kiel, Jeffrey W.; Duong, Timothy Q.

2014-01-01

Purpose To verify that a visual fixation protocol with cued eye blinks achieves sufficient stability for magnetic resonance imaging (MRI) blood-flow measurements and to determine if choroidal blood flow (ChBF) changes with age in humans. Methods The visual fixation stability achievable during an MRI scan was measured in five normal subjects using an eye-tracking camera outside the MRI scanner. Subjects were instructed to blink immediately after recorded MRI sound cues but to otherwise maintain stable visual fixation on a small target. Using this fixation protocol, ChBF was measured with MRI using a 3 Tesla clinical scanner in 17 normal subjects (24–68 years old). Arterial and intraocular pressures (IOP) were measured to calculate perfusion pressure in the same subjects. Results The mean temporal fluctuations (standard deviation) of the horizontal and vertical displacements were 29 ± 9 μm and 38 ± 11 μm within individual fixation periods, and 50 ± 34 μm and 48 ± 19 μm across different fixation periods. The absolute displacements were 67 ± 31 μm and 81 ± 26 μm. ChBF was negatively correlated with age (R =−0.7, p = 0.003), declining 2.7 ml/100 ml/min per year. There were no significant correlations between ChBF versus perfusion pressure, arterial pressure, or IOP. There were also no significant correlations between age versus perfusion pressure, arterial pressure, or IOP. Multiple regression analysis indicated that age was the only measured independent variable that was significantly correlated with ChBF (p = 0.03). Conclusions The visual fixation protocol with cued eye blinks was effective in achieving sufficient stability for MRI measurements. ChBF had a significant negative correlation with age. PMID:24655028

Comparative Study of Intramedullary Hammertoe Fixation.

PubMed

Obrador, Caterina; Losa-Iglesias, Marta; Becerro-de-Bengoa-Vallejo, Ricardo; Kabbash, Christina A

2018-04-01

Temporary Kirschner wire fixation (K-wire) is a widely used, low-cost fixation method for the correction of hammertoe deformity. Reported complications associated with K-wires prompted the development of new implants over the past decade. However, there is a lack of literature on comparative studies analyzing functional outcomes using validated questionnaires. The purpose of this study was to analyze functional outcomes in patients who had undergone proximal interphalangeal joint fusion using 2 types of intramedullary implant, the Smart Toe and the TenFuse, and to compare them with the outcomes in patients treated with standard K-wire fixation. A retrospective review of operative hammertoe correction by a single surgeon was performed in 96 patients followed for more than 12 months. Functional outcome was assessed using the Foot Function Index (FFI), the Short Form 36 (SF-36), and the 10-point visual analog scale (VAS) validated questionnaires. Complications and fusion rates were also evaluated. Several patients in the study underwent corrections in different toes; thus, a total of 186 toes were included in the study. From these, 65 toes (34.9%) were treated with K-wire fixation, 94 (50.5%) with Smart Toe titanium implant, and 27 (14.5%) with TenFuse allograft implant. No statistically significant differences in functional outcome and incidence of complications were observed among the 3 fixation groups, although the 2 intramedullary implants were associated with greater fusion rates and patient satisfaction. Breakage of the Smart Toe implant was significantly higher than that of the other fixations, with 10.6% of implants breaking within the first year postoperatively. SF-36 and VAS scores decreased 12 months after surgery for the 3 types of fixation, with no statistically significant differences observed. The use of Smart Toe and TenFuse implants provided operative outcomes comparable to those obtained using a K-wire fixation and slightly better patient satisfaction. Our results suggest that utilization of these implants for hammertoe correction was a reasonable choice that provided good alignment, pain reduction, and improved function at final follow-up. However, they are more expensive than K-wires. For this reason, in-depth cost-benefit studies would be required to justify their use as a standard treatment. Level III, comparative series.

[Pedicle flap transfer combined with external fixator to treat leg open fracture with soft tissue defect].

PubMed

Luo, Zhongchun; Lou, Hua; Jiang, Junwei; Song, Chunlin; Gong, Min; Wang, Yongcai

2008-08-01

To investigate the clinical results of treating leg open fracture with soft tissue defect by pedicle flap transfer in combination with external fixator. From May 2004 to June 2007, 12 cases of leg open fracture with soft tissue defect, 9 males and 3 females aged 18-75 years, were treated. Among them, 8 cases were caused by traffic accidents, 2 crush, 1 falling and 1 mechanical accident. According to the Gustilo Classification, there were 2 cases of type II, 5 of type IIIA and 5 of type IIIB. There were 2 cases of upper-tibia fracture, 3 of middle-tibia and 7 of middle-lower. The sizes of soft tissue defect ranged from 5 cm x 3 cm to 22 cm x 10 cm.The sizes of exposed bone ranged from 3 cm x 2 cm to 6 cm x 3 cm. The course of the disease was 1-12 hours. Fracture fixation was reached by external fixators or external fixators and limited internal fixation with Kirschner wire. The wounds with exposed tendons and bones were repaired by ipsilateral local rotation flap, sural neurocutaneous flap and saphenous nerve flap. The size of selected flap ranged from 5 cm x 4 cm to 18 cm x 12 cm. Granulation wounds were repaired by skin grafting or direct suture. All patients were followed up for 6 months to 2 years. All patients survived, among whom 2 with the wound edge infection and 1 with the distal necrosis were cured by changing the dressing, 8 with pin hole infection were treated by taking out the external fixator, 1 with nonunion received fracture healing after bone graft in comminuted fracture of lower tibia, 2 suffered delayed union in middle-lower tibia fracture. The ROM of ankle in 3 cases was mildly poor with surpass-joint fixation, with plantar extension of 0-10 degrees and plantar flexion of 10-30 degrees, while the others had plantar extension of 10-20 degrees and plantar flexion of 30-50 degrees. The method of pedicle flap transfer combined with external fixator is safe and effective for the leg open fracture with soft tissue defect.

Individualized 3D printing navigation template for pedicle screw fixation in upper cervical spine

PubMed Central

Guo, Fei; Dai, Jianhao; Zhang, Junxiang; Ma, Yichuan; Zhu, Guanghui; Shen, Junjie; Niu, Guoqi

2017-01-01

Purpose Pedicle screw fixation in the upper cervical spine is a difficult and high-risk procedure. The screw is difficult to place rapidly and accurately, and can lead to serious injury of spinal cord or vertebral artery. The aim of this study was to design an individualized 3D printing navigation template for pedicle screw fixation in the upper cervical spine. Methods Using CT thin slices data, we employed computer software to design the navigation template for pedicle screw fixation in the upper cervical spine (atlas and axis). The upper cervical spine models and navigation templates were produced by 3D printer with equal proportion, two sets for each case. In one set (Test group), pedicle screws fixation were guided by the navigation template; in the second set (Control group), the screws were fixed under fluoroscopy. According to the degree of pedicle cortex perforation and whether the screw needed to be refitted, the fixation effects were divided into 3 types: Type I, screw is fully located within the vertebral pedicle; Type II, degree of pedicle cortex perforation is <1 mm, but with good internal fixation stability and no need to renovate; Type III, degree of pedicle cortex perforation is >1 mm or with the poor internal fixation stability and in need of renovation. Type I and Type II were acceptable placements; Type III placements were unacceptable. Results A total of 19 upper cervical spine and 19 navigation templates were printed, and 37 pedicle screws were fixed in each group. Type I screw-placements in the test group totaled 32; Type II totaled 3; and Type III totaled 2; with an acceptable rate of 94.60%. Type I screw placements in the control group totaled 23; Type II totaled 3; and Type III totaled 11, with an acceptable rate of 70.27%. The acceptability rate in test group was higher than the rate in control group. The operation time and fluoroscopic frequency for each screw were decreased, compared with control group. Conclusion The individualized 3D printing navigation template for pedicle screw fixation is easy and safe, with a high success rate in the upper cervical spine surgery. PMID:28152039

DNA elution from buccal cells stored on Whatman FTA Classic Cards using a modified methanol fixation method.

PubMed

Johanson, Helene C; Hyland, Valentine; Wicking, Carol; Sturm, Richard A

2009-04-01

We describe here a method for DNA elution from buccal cells and whole blood both collected onto Whatman FTA technology, using methanol fixation followed by an elution PCR program. Extracted DNA is comparable in quality to published Whatman FTA protocols, as judged by PCR-based genotyping. Elution of DNA from the dried sample is a known rate-limiting step in the published Whatman FTA protocol; this method enables the use of each 3-mm punch of sample for several PCR reactions instead of the standard, one PCR reaction per sample punch. This optimized protocol therefore extends the usefulness and cost effectiveness of each buccal swab sample collected, when used for nucleic acid PCR and genotyping.

Cell fixation and preservation for droplet-based single-cell transcriptomics.

PubMed

Alles, Jonathan; Karaiskos, Nikos; Praktiknjo, Samantha D; Grosswendt, Stefanie; Wahle, Philipp; Ruffault, Pierre-Louis; Ayoub, Salah; Schreyer, Luisa; Boltengagen, Anastasiya; Birchmeier, Carmen; Zinzen, Robert; Kocks, Christine; Rajewsky, Nikolaus

2017-05-19

Recent developments in droplet-based microfluidics allow the transcriptional profiling of thousands of individual cells in a quantitative, highly parallel and cost-effective way. A critical, often limiting step is the preparation of cells in an unperturbed state, not altered by stress or ageing. Other challenges are rare cells that need to be collected over several days or samples prepared at different times or locations. Here, we used chemical fixation to address these problems. Methanol fixation allowed us to stabilise and preserve dissociated cells for weeks without compromising single-cell RNA sequencing data. By using mixtures of fixed, cultured human and mouse cells, we first showed that individual transcriptomes could be confidently assigned to one of the two species. Single-cell gene expression from live and fixed samples correlated well with bulk mRNA-seq data. We then applied methanol fixation to transcriptionally profile primary cells from dissociated, complex tissues. Low RNA content cells from Drosophila embryos, as well as mouse hindbrain and cerebellum cells prepared by fluorescence-activated cell sorting, were successfully analysed after fixation, storage and single-cell droplet RNA-seq. We were able to identify diverse cell populations, including neuronal subtypes. As an additional resource, we provide 'dropbead', an R package for exploratory data analysis, visualization and filtering of Drop-seq data. We expect that the availability of a simple cell fixation method will open up many new opportunities in diverse biological contexts to analyse transcriptional dynamics at single-cell resolution.

Fragment-Specific Fixation Versus Volar Locking Plates in Primarily Nonreducible or Secondarily Redisplaced Distal Radius Fractures: A Randomized Controlled Study.

PubMed

Landgren, Marcus; Abramo, Antonio; Geijer, Mats; Kopylov, Philippe; Tägil, Magnus

2017-03-01

To compare the patient-reported, clinical, and radiographic outcome of 2 methods of internal fixation in distal radius fractures. Fifty patients, mean age 56 years (range, 21-69 years) with primarily nonreducible or secondarily redisplaced distal radius fractures were randomized to open reduction internal fixation using volar locking plates (n = 25) or fragment-specific fixation (n = 25). The patients were assessed on grip strength, range of motion, patient-reported outcome (Quick Disabilities of the Arm, Shoulder, and Hand), pain (visual analog scale), health-related quality of life (Short Form-12 [SF-12]), and radiographic evaluation. Grip strength at 12 months was the primary outcome measure. At 12 months, no difference was found in grip strength, which was 90% of the uninjured side in the volar plate group and 87% in the fragment-specific fixation group. No differences were found in range of motion and the median Quick Disabilities of the Arm, Shoulder, and Hand score was 5 in both groups. The overall complication rate was significant, 21% in the volar locking plate group, compared with 52% in the fragment-specific group. In treatment of primarily nonreducible or secondarily redisplaced distal radius fractures, volar locking plates and fragment-specific fixation both achieve good and similar patient-reported outcomes, although more complications were recorded in the fragment-specific group. Therapeutic II. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Endoscopic stent suture fixation for prevention of esophageal stent migration during prolonged dilatation for achalasia treatment.

PubMed

Rieder, E; Asari, R; Paireder, M; Lenglinger, J; Schoppmann, S F

2017-04-01

The aim of this study is to compare endoscopic stent suture fixation with endoscopic clip attachment or the use of partially covered stents (PCS) regarding their capability to prevent stent migration during prolonged dilatation in achalasia. Large-diameter self-expanding metal stents (30 mm × 80 mm) were placed across the gastroesophageal junction in 11 patients with achalasia. Stent removal was scheduled after 4 to 7 days. To prevent stent dislocation, endoscopic clip attachment, endoscopic stent suture fixation, or PCS were used. The Eckardt score was evaluated before and 6 months after prolonged dilatation. After endoscopic stent suture fixation, no (0/4) sutured stent migrated. When endoscopic clips were used, 80% (4/5) clipped stents migrated (p = 0.02). Of two PCS (n = 2), one migrated and one became embedded leading to difficult stent removal. Technical adverse events were not seen in endoscopic stent suture fixation but were significantly correlated with the use of clips or PCS (r = 0.828, p = 0.02). Overall, 72% of patients were in remission regarding their achalasia symptoms 6 months after prolonged dilatation. Endoscopic suture fixation of esophageal stents but not clip attachment appears to be the best method of preventing early migration of esophageal stents placed at difficult locations such as at the naive gastroesophageal junction. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[Staple fixation for the treatment of hamate metacarpal joint injury].

PubMed

Tang, Yang-Hua; Zeng, Lin-Ru; Huang, Zhong-Ming; Yue, Zhen-Shuang; Xin, Da-Wei; Xu, Can-Da

2014-03-01

To investigate the effcacy of the staple fixation for the treatment of hamate metacarpal joint injury. From May 2009 to November 2012,16 patients with hamate metacarpal joint injury were treated with staple fixation including 10 males and 6 females with an average age of 33.6 years old ranging from 21 to 57 years. Among them, 11 cases were on the fourth or fifth metacarpal base dislocation without fractures, 5 cases were the fourth or fifth metacarpal base dislocation with avulsion fractures of the back of hamatum. Regular X-ray review was used to observe the fracture healing, joint replacement and position of staple fixation. The function of carpometacarpal joint and metacarpophalangeal joint were evaluated according to ASIA (TAM) system evaluation method. All incision were healed well with no infection. All patients were followed up from 16 to 24 months with an average of (10.0 +/- 2.7) months. No dislocation recurred, the position of internal fixator was good,no broken nail and screw withdrawal were occurred. Five patients with avulsion fracture of the back of hamatum achieved bone healing. The function of carpometacarpal joint and metacarpophalangeal was excellent in 10 cases,good in 5 cases, moderate in 1 case. The application of the staple for the treatment of hamatometacarpal joint injury has the advantages of simple operation, small trauma, reliable fixation, early postoperative function exercise and other advantages, which is the ideal operation mode for hamatometacarpal joint injury.

Successful correction of tibial bone deformity through multiple surgical procedures, liquid nitrogen-pretreated bone tumor autograft, three-dimensional external fixation, and internal fixation in a patient with primary osteosarcoma: a case report.

PubMed

Takeuchi, Akihiko; Yamamoto, Norio; Shirai, Toshiharu; Nishida, Hideji; Hayashi, Katsuhiro; Watanabe, Koji; Miwa, Shinji; Tsuchiya, Hiroyuki

2015-12-07

In a previous report, we described a method of reconstruction using tumor-bearing autograft treated by liquid nitrogen for malignant bone tumor. Here we present the first case of bone deformity correction following a tumor-bearing frozen autograft via three-dimensional computerized reconstruction after multiple surgeries. A 16-year-old female student presented with pain in the left lower leg and was diagnosed with a low-grade central tibial osteosarcoma. Surgical bone reconstruction was performed using a tumor-bearing frozen autograft. Bone union was achieved at 7 months after the first surgical procedure. However, local tumor recurrence and lung metastases occurred 2 years later, at which time a second surgical procedure was performed. Five years later, the patient developed a 19° varus deformity and underwent a third surgical procedure, during which an osteotomy was performed using the Taylor Spatial Frame three-dimensional external fixation technique. A fourth corrective surgical procedure was performed in which internal fixation was achieved with a locking plate. Two years later, and 10 years after the initial diagnosis of tibial osteosarcoma, the bone deformity was completely corrected, and the patient's limb function was good. We present the first report in which a bone deformity due to a primary osteosarcoma was corrected using a tumor-bearing frozen autograft, followed by multiple corrective surgical procedures that included osteotomy, three-dimensional external fixation, and internal fixation.

Finite element analysis of locking plate and two types of intramedullary nails for treating mid-shaft clavicle fractures.

PubMed

Ni, Ming; Niu, Wenxin; Wong, Duo Wai-Chi; Zeng, Wei; Mei, Jiong; Zhang, Ming

2016-08-01

Both plate and intramedullary nail fixations, including straight and anatomic nails, have been clinically adopted for the treatment of displaced mid-shaft clavicle fractures. However, the biomechanical performances of these fixations and implants have not been well evaluated. This study aims to compare the construct stability, stress distribution and fracture micro-motion of three fixations based on finite element (FE) method. The FE model of clavicle was reconstructed from CT images of a male volunteer. A mid-shaft fracture gap was created in the intact clavicle. Three fixation styles were simulated including locking plate (LP), anatomic intramedullary nail (CRx), and straight intramedullary nail (RCP). Two loading scenarios (axial compression and inferior bending) were applied at the distal end of the clavicle to simulate arm abduction, while the sternal end was fixed. Under both conditions, the LP was the stiffest, followed by the CRx, and the RCP was the weakest. LP also displayed a more evenly stress distribution for both implant and bone. RCP had a higher stress compared with CRx in both conditions. Moreover, all implants sustained higher stress level under the loading condition of bending than compression. The plate fixation significantly stabilizes the fracture gap, reduces the implant stress, and serves as the recommended fixation for the mid-shaft clavicle fracture. The CRx is an alternative device to treat clavicle shaft fracture, but the shoulder excessive activities should be avoided after operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Management of distal femoral periprosthetic fractures by distal femoral locking plate: A retrospective study.

PubMed Central

Thukral, Rajiv; Marya, SKS; Singh, Chandeep

2015-01-01

Background: Management of periprosthetic supracondylar femoral fractures is difficult. Osteoporosis, comminution and bone loss, compromise stability with delayed mobility and poor functional outcomes. Open reduction and internal fixation (ORIF) with anatomic distal femoral (DF) locking plate permits early mobilization. However, this usually necessitates bone grafting (BG). Biological fixation using minimally invasive techniques minimizes periosteal stripping and morbidity. Materials and Methods: 31 patients with comminuted periprosthetic DF fractures were reviewed retrospectively from October 2006 to September 2012. All patients underwent fixation using a DF locking compression plate (Synthes). 17 patients underwent ORIF with primary BG, whereas 14 were treated by closed reduction (CR) and internal fixation using biological minimally invasive techniques. Clinical and radiological followup were recorded for an average 36 months. Results: Mean time to union for the entire group was 5.6 months (range 3-9 months). Patients of ORIF group took longer (Mean 6.4 months, range 4.5-9 months) than the CR group (mean 4.6 months, range 3-7 months). Three patients of ORIF and one in CR group had poor results. Mean knee society scores were higher for CR group at 6 months, but nearly identical at 12 months, with similar eventual range of motion. Discussion: Locked plating of comminuted periprosthetic DF fractures permits stable rigid fixation and early mobilization. Fixation using minimally invasive biological techniques minimizes morbidity and may obviate the need for primary BG. PMID:26015610

Preparation and Evaluation of Solid Dispersion Tablets by a Simple and Manufacturable Wet Granulation Method Using Porous Calcium Silicate.

PubMed

Fujimoto, Yumi; Hirai, Nobuaki; Takatani-Nakase, Tomoka; Takahashi, Koichi

2016-01-01

The aim of this study was to prepare and evaluate solid dispersion tablets containing a poorly water-soluble drug using porous calcium silicate (PCS) by a wet granulation method. Nifedipine (NIF) was used as the model poorly water-soluble drug. Solid dispersion tablets were prepared with the wet granulation method using ethanol and water by a high-speed mixer granulator. The binder and disintegrant were selected from 7 and 4 candidates, respectively. The dissolution test was conducted using the JP 16 paddle method. The oral absorption of NIF was studied in fasted rats. Xylitol and crospovidone were selected as the binder and disintegrant, respectively. The dissolution rates of NIF from solid dispersion formulations were markedly enhanced compared with NIF powder and physical mixtures. Powder X-ray diffraction (PXRD) confirmed the reduced crystallinity of NIF in the solid dispersion formulations. Fourier transform infrared (FT-IR) showed the physical interaction between NIF and PCS in the solid dispersion formulations. NIF is present in an amorphous state in granules prepared by the wet granulation method using water. The area under the plasma concentration-time curve (AUC) and peak concentration (C(max)) values of NIF after dosing rats with the solid dispersion granules were significantly greater than those after dosing with NIF powder. The solid dispersion formulations of NIF prepared with PCS using the wet granulation method exhibited accelerated dissolution rates and superior oral bioavailability. This method is very simple, and may be applicable to the development of other poorly water-soluble drugs.

Evaluation of the Effectiveness of Wet Blast Cleaning Methods of Surface Preparation

DTIC Science & Technology

1985-06-01

for Air Abrasive Wet Blast: Complete System Water Abrasive Mixing Chamber in Slurry Blast Unit Schematic of unit Control Unit Slurry Blast — Air/Water...this discussion we present some general. user guidelines regarding what to look for in con- sidering the use or purchase of wet blasting equipment...These units use compressed air as the medium to propel the eroding material. They differ from air abrasive wet blast units in that the abrasive is mixed

Preparation of Nonhuman Primate Eyes for Histological Evaluation After Retinal Gene Transfer.

PubMed

Bell, Peter; Yu, Hongwei; Kuntz, Leah; Ahonkhai, Omua; Tretiakova, Anna; Limberis, Maria P; Wilson, James M

2018-06-01

To evaluate gene therapy for retinal disorders, appropriate models of the human eye are needed. Nonhuman primate eyes offer significant advantages over rodent eyes. However, current preparation methods have limitations. Here, a protocol is described for histological processing of nonhuman primate eyes after gene transfer. The user dissects unfixed eyes, flattens the globe parts within filter paper, and performs formalin fixation and paraffin embedding. This method obviates the need for harsh fixatives, allowing subsequent immunostaining or in situ hybridization while preserving tissue integrity for histopathological evaluation. Moreover, the straight orientation of the retinal cell layers is ideal for image analysis.

Fixation methods for electron microscopy of human and other liver

PubMed Central

Wisse, Eddie; Braet, Filip; Duimel, Hans; Vreuls, Celien; Koek, Ger; Olde Damink, Steven WM; van den Broek, Maartje AJ; De Geest, Bart; Dejong, Cees HC; Tateno, Chise; Frederik, Peter

2010-01-01

For an electron microscopic study of the liver, expertise and complicated, time-consuming processing of hepatic tissues and cells is needed. The interpretation of electron microscopy (EM) images requires knowledge of the liver fine structure and experience with the numerous artifacts in fixation, embedding, sectioning, contrast staining and microscopic imaging. Hence, the aim of this paper is to present a detailed summary of different methods for the preparation of hepatic cells and tissue, for the purpose of preserving long-standing expertise and to encourage new investigators and clinicians to include EM studies of liver cells and tissue in their projects. PMID:20556830

A comprehensive prediction and evaluation method of pilot workload

PubMed Central

Feng, Chuanyan; Wanyan, Xiaoru; Yang, Kun; Zhuang, Damin; Wu, Xu

2018-01-01

BACKGROUND: The prediction and evaluation of pilot workload is a key problem in human factor airworthiness of cockpit. OBJECTIVE: A pilot traffic pattern task was designed in a flight simulation environment in order to carry out the pilot workload prediction and improve the evaluation method. METHODS: The prediction of typical flight subtasks and dynamic workloads (cruise, approach, and landing) were built up based on multiple resource theory, and a favorable validity was achieved by the correlation analysis verification between sensitive physiological data and the predicted value. RESULTS: Statistical analysis indicated that eye movement indices (fixation frequency, mean fixation time, saccade frequency, mean saccade time, and mean pupil diameter), Electrocardiogram indices (mean normal-to-normal interval and the ratio between low frequency and sum of low frequency and high frequency), and Electrodermal Activity indices (mean tonic and mean phasic) were all sensitive to typical workloads of subjects. CONCLUSION: A multinominal logistic regression model based on combination of physiological indices (fixation frequency, mean normal-to-normal interval, the ratio between low frequency and sum of low frequency and high frequency, and mean tonic) was constructed, and the discriminate accuracy was comparatively ideal with a rate of 84.85%. PMID:29710742

New pediatric vision screener, part II: electronics, software, signal processing and validation.

PubMed

Gramatikov, Boris I; Irsch, Kristina; Wu, Yi-Kai; Guyton, David L

2016-02-04

We have developed an improved pediatric vision screener (PVS) that can reliably detect central fixation, eye alignment and focus. The instrument identifies risk factors for amblyopia, namely eye misalignment and defocus. The device uses the birefringence of the human fovea (the most sensitive part of the retina). The optics have been reported in more detail previously. The present article focuses on the electronics and the analysis algorithms used. The objective of this study was to optimize the analog design, data acquisition, noise suppression techniques, the classification algorithms and the decision making thresholds, as well as to validate the performance of the research instrument on an initial group of young test subjects-18 patients with known vision abnormalities (eight male and 10 female), ages 4-25 (only one above 18) and 19 controls with proven lack of vision issues. Four statistical methods were used to derive decision making thresholds that would best separate patients with abnormalities from controls. Sensitivity and specificity were calculated for each method, and the most suitable one was selected. Both the central fixation and the focus detection criteria worked robustly and allowed reliable separation between normal test subjects and symptomatic subjects. The sensitivity of the instrument was 100 % for both central fixation and focus detection. The specificity was 100 % for central fixation and 89.5 % for focus detection. The overall sensitivity was 100 % and the overall specificity was 94.7 %. Despite the relatively small initial sample size, we believe that the PVS instrument design, the analysis methods employed, and the device as a whole, will prove valuable for mass screening of children.

How task demands influence scanpath similarity in a sequential number-search task.

PubMed

Dewhurst, Richard; Foulsham, Tom; Jarodzka, Halszka; Johansson, Roger; Holmqvist, Kenneth; Nyström, Marcus

2018-06-07

More and more researchers are considering the omnibus eye movement sequence-the scanpath-in their studies of visual and cognitive processing (e.g. Hayes, Petrov, & Sederberg, 2011; Madsen, Larson, Loschky, & Rebello, 2012; Ni et al., 2011; von der Malsburg & Vasishth, 2011). However, it remains unclear how recent methods for comparing scanpaths perform in experiments producing variable scanpaths, and whether these methods supplement more traditional analyses of individual oculomotor statistics. We address this problem for MultiMatch (Jarodzka et al., 2010; Dewhurst et al., 2012), evaluating its performance with a visual search-like task in which participants must fixate a series of target numbers in a prescribed order. This task should produce predictable sequences of fixations and thus provide a testing ground for scanpath measures. Task difficulty was manipulated by making the targets more or less visible through changes in font and the presence of distractors or visual noise. These changes in task demands led to slower search and more fixations. Importantly, they also resulted in a reduction in the between-subjects scanpath similarity, demonstrating that participants' gaze patterns became more heterogenous in terms of saccade length and angle, and fixation position. This implies a divergent strategy or random component to eye-movement behaviour which increases as the task becomes more difficult. Interestingly, the duration of fixations along aligned vectors showed the opposite pattern, becoming more similar between observers in 2 of the 3 difficulty manipulations. This provides important information for vision scientists who may wish to use scanpath metrics to quantify variations in gaze across a spectrum of perceptual and cognitive tasks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhancement of Apoptosis by Titanium Alloy Internal Fixations during Microwave Treatments for Fractures: An Animal Study

PubMed Central

Zhang, Lina; Ye, Dongmei; Feng, Xianxuan; Fu, Tengfei; Bai, Yuehong

2015-01-01

Objective Microwaves are used in one method of physical therapy and can increase muscle tissue temperature which is useful for improving muscle, tendon and bone injuries. In the study, we sought to determine whether titanium alloy internal fixations influence apoptosis in tissues subjected to microwave treatments at 2,450 MHz and 40 W during the healing of fractures because this issue is not yet fully understood. Methods In this study, titanium alloy internal fixations were used to treat 3.0-mm transverse osteotomies in the middle of New Zealand rabbits’ femurs. After the operation, 30-day microwave treatments were applied to the 3.0 mm transverse osteotomies 3 days after the operation. The changes in the temperatures of the muscle tissues in front of the implants or the 3.0 mm transverse osteotomies were measured during the microwave treatments. To characterize the effects of titanium alloy internal fixations on apoptosis in the muscles after microwave treatment, we performed TUNEL assays, fluorescent real-time (quantitative) PCR, western blotting analyses, reactive oxygen species (ROS) detection and transmission electron microscopy examinations. Results The temperatures were markedly increased in the animals with the titanium alloy implants. Apoptosis in the muscle cells of the implanted group was significantly more extensive than that in the non-implanted control group at different time points. Transmission electron microscopy examinations of the skeletal muscles of the implanted groups revealed muscular mitochondrial swelling, vacuolization. ROS, Bax and Hsp70 were up-regulated, and Bcl-2 was down-regulated in the implanted group. Conclusion Our results suggest that titanium alloy internal fixations caused greater muscular tissue cell apoptosis following 2,450 MHz, 40 W microwave treatments in this rabbit femur fracture models. PMID:26132082

Minimally invasive anterior pelvic internal fixation: An anatomic study comparing Pelvic Bridge to INFIX.

PubMed

Reichel, Lee M; MacCormick, Lauren M; Dugarte, Anthony J; Rizkala, Amir R; Graves, Sara C; Cole, Peter A

2018-02-01

Anterior external fixation for pelvic ring fractures has shown to effectively improve stability and reduce mortality. However, these fixators can be associated with substantial morbidity such as pin tract infection, premature loss of fixation, and decreased quality of life in patients. Recently, two new methods of subcutaneous anterior pelvic internal fixation have been developed; the INFIX and the Pelvic Bridge. These methods have the purported advantages of lower wound complications, less surgical site pain, and improved quality of life. We sought to investigate the measured distances to critical anatomic structures, as well as the qualitative and topographic differences notable during implantation of both devices in the same cadaveric specimen. The Pelvic Bridge and INFIX were implanted in eleven fresh cadavers. Distances were then measured to: the superficial inguinal ring, round ligament, spermatic cord, lateral femoral cutaneous nerve (LFCN), femoral nerve, femoral artery, and femoral vein. Observations regarding implantation and topography were also recorded. The INFIX had greater measured distances from all structures except for the LFCN, in which its proximity placed this structure at risk. Neither device appears to put other critical structures at risk in the supine position. Significant implantation and topographic differences exist between the devices. The INFIX application lacked "safety margins" concerning the LFCN in 10/11 (90.9%) specimens, while Pelvic Bridge placement lacked "safety margins" with regard to the right superficial ring (1/11, 9%) and the right spermatic cord (1/11, 9%). Both the Pelvic Bridge and INFIX lie at safe distances from most critical pelvic structures in the supine position, though INFIX application places the LFCN at risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

A customized fixation plate with novel structure designed by topological optimization for mandibular angle fracture based on finite element analysis.

PubMed

Liu, Yun-Feng; Fan, Ying-Ying; Jiang, Xian-Feng; Baur, Dale A

2017-11-15

The purpose of this study was to design a customized fixation plate for mandibular angle fracture using topological optimization based on the biomechanical properties of the two conventional fixation systems, and compare the results of stress, strain and displacement distributions calculated by finite element analysis (FEA). A three-dimensional (3D) virtual mandible was reconstructed from CT images with a mimic angle fracture and a 1 mm gap between two bone segments, and then a FEA model, including volume mesh with inhomogeneous bone material properties, three loading conditions and constraints (muscles and condyles), was created to design a customized plate using topological optimization method, then the shape of the plate was referenced from the stress concentrated area on an initial part created from thickened bone surface for optimal calculation, and then the plate was formulated as "V" pattern according to dimensions of standard mini-plate finally. To compare the biomechanical behavior of the "V" plate and other conventional mini-plates for angle fracture fixation, two conventional fixation systems were used: type A, one standard mini-plate, and type B, two standard mini-plates, and the stress, strain and displacement distributions within the three fixation systems were compared and discussed. The stress, strain and displacement distributions to the angle fractured mandible with three different fixation modalities were collected, respectively, and the maximum stress for each model emerged at the mandibular ramus or screw holes. Under the same loading conditions, the maximum stress on the customized fixation system decreased 74.3, 75.6 and 70.6% compared to type A, and 34.9, 34.1, and 39.6% compared to type B. All maximum von Mises stresses of mandible were well below the allowable stress of human bone, as well as maximum principal strain. And the displacement diagram of bony segments indicated the effect of treatment with different fixation systems. The customized fixation system with topological optimized structure has good biomechanical behavior for mandibular angle fracture because the stress, strain and displacement within the plate could be reduced significantly comparing to conventional "one mini-plate" or "two mini-plates" systems. The design methodology for customized fixation system could be used for other fractures in mandible or other bones to acquire better mechanical behavior of the system and improve stable environment for bone healing. And together with SLM, the customized plate with optimal structure could be designed and fabricated rapidly to satisfy the urgent time requirements for treatment.

A method for trace element determination of single Daphnia specimens using total reflection X-ray fluorescence spectrometry

NASA Astrophysics Data System (ADS)

Mages, Margarete; Woelfl, Stefan; v. Tümpling jun, Wolf

2001-11-01

Two new preparation techniques for total-reflection X-ray fluorescence (TXRF) element determination of single freshwater crustacean specimens (dry weight: 3-40 μg ind -1) have been developed and tested using Daphnia pulex from a deep, oligotrophic freshwater lake located in southern Chile. Dry method: Specimens were washed with 0.2 μm filtered lake water and frozen in liquid nitrogen. The freeze-dried Daphnia specimens were weighed using an ultra-fine microbalance and placed on quartz glass carriers for TXRF analysis. Wet method: Specimens were washed with 0.2 μm filtered lake water and placed on quartz glass carriers for TXRF analysis and dried in air. The dry weight was determined using the previously established body length-dry weight relationship. Method validation for both the dry and the wet preparation method in combination with TXRF spectrometry for the element determination in small single freshwater crustaceans showed that both methods can be used for routine investigations. There were no significant differences between the dry and the wet methods concerning the elements Ca, K, Fe, Zn, Br, P, Cu, but the determination of Mn, S and Sr revealed significant differences between the two methods. It seems that the dry method yields more precise results, but the wet method is easier to handle in the field when samples cannot be fixed with liquid nitrogen.

CO(2) fixation through hydrogenation by chemical or enzymatic methods.

PubMed

Beller, Matthias; Bornscheuer, Uwe T

2014-04-25

Two birds with one stone: The simulaneous fixation of the greenhouse gas carbon dioxide and storage of the alternative fuel hydrogen can be accomplished with the formation of formic acid. In principle, this is now possible either with an enzymatic system based on a newly discovered bacterial hydrogen-dependent carbon dioxide reductase or by using organometallic catalysts at room temperature and ambient pressure. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

FAMI Screws for Mandibulo-Maxillary fixation in mandibular fracture treatment - Clinico-radiological evaluation.

PubMed

Kauke, Martin; Safi, Ali-Farid; Timmer, Marco; Nickenig, Hans-Joachim; Zöller, Joachim; Kreppel, Matthias

2018-04-01

Mandibulo-maxillary fixation (MMF) is indispensable for mandibular fracture treatment. Various means for MMF have been proposed, of which arch bars are widely considered to be the mainstay. However, disadvantages to this method have initiated a quest for an alternative, leading to the introduction of MMF screws. MMF screws have frequently been criticized for poor stability of fracture sites, root damage, hardware failure, and nerve damage. We retrospectively evaluate the FAMI (Fixation and Adaptation in Mandibular Injuries) screw in mandibular fracture treatment by scanning for clinically and radiologically visible complications. In total, 534 FAMI screws were used in the successful treatment of 96 males and 34 females. Condylar fractures were most commonly encountered, representing 120 of 241 fracture sites. 15 general fracture-related complications occurred, with the most common being nerve function impairment (3.8%) and postoperative malocclusion (4.6%). In nine cases (7%), clinically visible FAMI-screw-related complications occurred, with the most prevalent being screw loosening (2.3%) and mucosal signs of inflammation (3.1%). Duration of FAMI screws was associated with the occurrence of clinically visible complications (p = 0.042). Radiologically, clinically invisible dental hard tissue damage was noted in 21 individuals (16%). Therefore, FAMI screws seem to be a reliable and safe method for mandibulo-maxillary fixation. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Isotopic Biomarkers of Nitrogenase Metalloenzymes: Forging Links Between the Cycles of Nitrogen and Trace Metals

NASA Astrophysics Data System (ADS)

Zhang, X.; McRose, D. L.; Darnajoux, R.; Bellenger, J. P.; Kraepiel, A. M. L.

2015-12-01

Biological N2 fixation, catalyzed by the metalloenzyme nitrogenase, is a critical process that makes life possible on Earth. Environmental N2 fixation has been automatically attributed to canonical Mo-based nitrogenases despite over two decades of knowledge that two other metalloenzyme forms of nitrogenase exist: those containing catalytic V or Fe-only. A key area of missing information is the contribution of the "alternative" V and Fe-only nitrogenases, as the interpretation of field data to construct budgets and assess N availability depends on the type of nitrogenase metalloenzyme used to fix N2. Additionally, substantial changes in metal speciation over geological time may have favored the use of different metalloenzymes, with implications for evolution of the biosphere. Despite the potential importance of alternative nitrogenases in modern and ancient N cycling, few methods can determine their contributions to environmental N2 fixation. Here, we present new isotopic methods to distinguish between the activities of Mo, V, and Fe-only nitrogenases. We show evidence for alternative N2 fixation in diverse environments (cyanolichens, microbial mats, sediments, leaf litter), thereby linking a key process in the nitrogen cycle to specific metalloenzyme forms of nitrogenase. The results invite a reexamination of the conditions under which the different nitrogenase metalloenzymes are active and may lead to new insights into the coupling of the cycles of nitrogen and trace metals.

Segmental transport after unreamed intramedullary nailing. Preliminary report of a "Monorail" system.

PubMed

Raschke, M J; Mann, J W; Oedekoven, G; Claudi, B F

1992-09-01

The Ilizarov method of segmental bone transport has been shown to be an alternative to more conventional treatments of posttraumatic bony defects. After extensive clinical experience with the unreamed tibial nail in open fractures up to Grade IIIb, a new monorail fixation system for callus distraction and segmental bone transport was devised. This Monorail system is composed of an unreamed intramedullary (IM) nail and a unilateral AO distraction device. The new fixation method and the preliminary clinical experience are reported here. Four patients who previously sustained Grades II-IIIb open tibial fractures had an average bony defect of 9 cm. Two patients had previous bony infections. All patients had had serial debridements and myocutaneous flaps were required in three patients. An unreamed IM nail was inserted, and the transport device was applied. After an osteotomy, segmental transport was carried out until docking was achieved. The external fixator was removed after interlocking of the transported segment. The mean duration of external fixation was 17.9 days/cm and the mean period until roentgenographic consolidation of the distraction and nonunion site was 41.2 days/cm. There were two pin-tract infections but no IM infections. One nail broke after osseous consolidation of the regenerate at the distal interlocking site and required exchange. The goal of transport was achieved in all cases without angular or rotational deformity or length discrepancy. There were no neurovascular injuries.

Percutaneous distraction lengthening in brachymetacarpia.

PubMed

Volpi, Alexander D; Fragomen, Austin T

2011-08-08

Brachymetacarpia is a condition manifesting a shortened metacarpal that is caused by early closure of the epiphyseal plate and believed to arise idiopathically. The correction for brachymetacarpia is usually for cosmetic reasons as brachymetacarpia does not impair function. The literature indicates several different approaches to lengthening digits, including single-stage lengthening and rapid distraction lengthening with a bone graft. However, gradual distraction is the preferred method due to excellent cosmetic outcomes and few postoperative complications. This article reports a case of brachymetacarpia treated with distraction lengthening using a minimally invasive, percutaneous approach. A 16-year-old girl presented with a shortened left ring finger and underwent surgery to correct the deformity. The left ring finger measured 12 mm shorter than her right ring finger; however, there was normal mobility at the joints. In the operating room, an external fixator was attached using 4 self-drilling, self-tapping pins through several 3-mm skin incisions. The total fixation time was 14 weeks; however, the achieved length of 12 mm was achieved 6 weeks postoperatively. The healing index of the fixation period was 81 days/cm. The postoperative course and fixation period were uneventful, with no complications except for 2 pin infections that were treated with oral antibiotics. The method of gradual distraction lengthening in this case successfully achieved the desired length and yielded an excellent cosmetic result. Copyright 2011, SLACK Incorporated.

Management of Open Tibial Shaft Fractures: Does the Timing of Surgery Affect Outcomes?

PubMed

Duyos, Oscar A; Beaton-Comulada, David; Davila-Parrilla, Ariel; Perez-Lopez, Jose Carlos; Ortiz, Krystal; Foy-Parrilla, Christian; Lopez-Gonzalez, Francisco

2017-03-01

Open tibial shaft fractures require emergent care. Treatment with intravenous antibiotics and fracture débridement within 6 to 24 hours is recommended. Few studies have examined outcomes when surgical treatment is performed >24 hours after occurrence of the fracture. This retrospective study included 227 patients aged ≥18 years with isolated open tibial shaft fractures in whom the time to initial débridement was >24 hours. The statistical analysis was based on time from injury to surgical débridement, Gustilo-Anderson classification, method of fixation, union status, and infection status. Fractures débrided within 24 to 48 hours and 48 to 96 hours after injury did not show a statistically significant difference in terms of infection rates (P = 0.984). External fixation showed significantly greater infection rates (P = 0.044) and nonunion rates (P = 0.001) compared with intramedullary nailing. Open tibial shaft fractures should be débrided within 24 hours after injury. Our data indicate that after the 24-hour period and up to 4 days, the risk of infection remains relatively constant independent of the time to débridement. Patients treated with external fixation had more complications than did patients treated with other methods of fixation. Primary reamed intramedullary nailing appears to be a reasonable option for the management of Gustilo-Anderson types 1 and 2 open tibial shaft fractures. Level III retrospective study.

Efficacy of Retrievable Metallic Stent with Fixation String for Benign Stricture after Upper Gastrointestinal Surgery

PubMed Central

Kim, Jeong-Eun; Lee, Myungsu; Hur, Saebeom; Kim, Minuk; Lee, Sang Hwan; Cho, Soo Buem; Kim, Chan Sun; Han, Joon Koo

2016-01-01

Objective To determine the efficacy of retrievable metallic stent with fixation string for benign anastomotic stricture after upper gastrointestinal (UGI) surgery. Materials and Methods From June 2009 to May 2015, a total of 56 retrievable metallic stents with fixation string were placed under fluoroscopy guidance in 42 patients who were diagnosed with benign anastomotic stricture after UGI surgery. Clinical success was defined as achieving normal regular diet (NRD). Results The clinical success rate after the first stent placement was 57.1% (24/42). After repeated stent placement and/or balloon dilation, the clinical success rate was increased to 83.3% (35/42). Six (14.3%) patients required surgical revision to achieve NRD. One (2.4%) patient failed to achieve NRD. Stent migration occurred in 60.7% (34/56) of patients. Successful rate of removing the stent using fixation string and angiocatheter was 94.6% (53/56). Distal migration occurred in 12 stents. Of the 12 stents, 10 (83.3%) were successfully removed whereas 2 could not be removed. No complication occurred regarding distal migration. Conclusion Using retrievable metallic stent with a fixation string is a feasible option for managing early benign anastomotic stricture after UGI surgery. It can reduce complications caused by distal migration of the stent. PMID:27833405

Anesthetic and Surgical Management of a Bilateral Mandible Fracture in a Patient With Charcot-Marie-Tooth Disease: A Case Report.

PubMed

Smith, Jeffrey D; Minkin, Patton; Lindsey, Sean; Bovino, Brian

2015-10-01

This report describes the case of a 74-year-old man who had been diagnosed with Charcot-Marie-Tooth disease as a child. Because the patient had serious motor and sensory neuropathy associated with his disease, special anesthetic and surgical recommendations had to be considered before he underwent general anesthesia to repair his mandibular fracture. Repair of the mandible was performed under general anesthesia with a nasal endotracheal tube and the use of the nondepolarizing muscle relaxant rocuronium. Open reduction and internal fixation through extraoral approaches were used to fixate the displaced right subcondylar and symphyseal fractures. A closed reduction approach using maxillary fixation screws and a mandibular arch bar with light elastic guidance was used to treat a nondisplaced fracture of the left mandibular ramus. Rigid fixation allowed for avoidance of a period of intermaxillary fixation. General anesthesia and muscle relaxant were administered without complication. Treatment of bilateral mandibular fractures with combined open and closed approaches resulted in restoration of premorbid occlusion and masticatory function. Repair of mandibular fractures under general anesthesia appears to be a safe procedure in patients with Charcot-Marie-Tooth disease when appropriate anesthetic and surgical methods are used. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Vibration Testing Procedures for Bone Stiffness Assessment in Fractures Treated with External Fixation.

PubMed

Mattei, Lorenza; Longo, Antonia; Di Puccio, Francesca; Ciulli, Enrico; Marchetti, Stefano

2017-04-01

A bone healing assessment is crucial for the successful treatment of fractures, particularly in terms of the timing of support devices. However, in clinical practice, this assessment is only made qualitatively through bone manipulation and X-rays, and hence cannot be repeated as often as might be required. The present study reconsiders the quantitative method of frequency response analysis for healing assessments, and specifically for fractures treated with an external fixator. The novelty consists in the fact that bone excitation and response are achieved through fixator pins, thus overcoming the problem of transmission through soft-tissues and their damping effect. The main objective was to develop and validate a test procedure in order to characterize the treated bone. More than 80 tests were performed on a tibia phantom alone, a phantom with pins, and a phantom with a complete fixator. Different excitation techniques and input-output combinations were compared. The results demonstrated the effectiveness of a procedure based on impact tests using a micro-hammer. Pins and fixator were demonstrated to influence the frequency response of the phantom by increasing the number of resonant frequencies. This procedure will be applied in future studies to monitor healing both in in vitro and in vivo conditions.

[Technology of cementless hip endoprosthetics].

PubMed

Ungethüm, M; Blömer, W

1987-06-01

The success achieved with non-cemented hip arthroplasty depends mainly on the stability of the fixation, the quality of the stabilizing bone being just as important as favourable biomechanical conditions. The results of the intensive research and development with respect to the particular features of a non-cemented hip endoprosthesis can be divided into the following basic categories: Biomechanical aspects with special reference to bone related to the design of the prosthesis; material characteristics, such as fatigue strength, tribology, corrosion resistance, and biocompatibility; and development of new materials and coatings to permit direct bonding of implant and bone. With regard to the stem of hip prostheses, the different design parameters of various types are examined to determine their typical design characteristics, such as bearing surface of the collar, geometry of cross section, anatomically adapted shaping, and surface of the implant forming the contact with the bone. The latter can be divided into macroprofiles and macro- and micro-porous coated surfaces. On the other hand, the methods of cementless fixation of acetabular cups can be primarily divided into conical and spherical screw fixation and pegged fixation with additional macroprofiles of porous surfaces. In a separate study of the biomechanical aspects of screwed sockets, the special importance of socket shape and thread geometry are presented with reference to primary stability and long-term fixation of prostheses.

Nitrogen Fixation By Sulfate-Reducing Bacteria in Coastal and Deep-Sea Sediments

NASA Astrophysics Data System (ADS)

Bertics, V. J.; Löscher, C.; Salonen, I.; Schmitz-Streit, R.; Lavik, G.; Kuypers, M. M.; Treude, T.

2011-12-01

Sulfate-reducing bacteria (SRB) can greatly impact benthic nitrogen (N) cycling, by for instance inhibiting coupled denitrification-nitrification through the production of sulfide or by increasing the availability of fixed N in the sediment via dinitrogen (N2)-fixation. Here, we explored several coastal and deep-sea benthic habitats within the Atlantic Ocean and Baltic Sea, for the occurrence of N2-fixation mediated by SRB. A combination of different methods including microbial rate measurements of N2-fixation and sulfate reduction, geochemical analyses (porewater nutrient profiles, mass spectrometry), and molecular analyses (CARD-FISH, HISH-SIMS, "nested" PCR, and QPCR) were applied to quantify and identify the responsible processes and organisms, respectively. Furthermore, we looked deeper into the question of whether the observed nitrogenase activity was associated with the final incorporation of N into microbial biomass or whether the enzyme activity served another purpose. At the AGU Fall Meeting, we will present and compare data from numerous stations with different water depths, temperatures, and latitudes, as well as differences in key geochemical parameters, such as organic carbon content and oxygen availability. Current metabolic and molecular data indicate that N2-fixation is occurring in many of these benthic environments and that a large part of this activity may linked to SRB.

Kirschner-wire fixation for postburn flexion contracture deformity and consequences on articular surface.

PubMed

Sungur, Nezih; Ulusoy, Mustafa Gürhan; Boyacgil, Süreyya; Ortaparmak, Hülya; Akyüz, Mihriban; Ortak, Turgut; Koçer, Uğur; Sensöz, Omer

2006-02-01

Kirschner-wire (K-wire) fixation for 3-6 weeks is an approved method for stabilization of the fingers after the release of flexion contracture deformity. On the other hand, articular surface damage in small joints due to pin fixation is still a topic of debate. Reports claiming permanent joint destruction due to this procedure exist in the literature. To clarify this doubt, a prospective study was carried out in 72 patients with flexion contracture of the hand fingers. After the surgical release of the deformity, immobilization of the interphalangeal (IP) and metacarpophalangeal (MCP) joints was carried out with K-wire fixation for 3 weeks. Clinical evaluation of the patients was accomplished with total active motion (TAM), grip, and pinch force measurements, whereas magnetic resonance (MR) and radionuclide imaging were used as radiodiagnostic tools. Mean follow-up period of the patients was 32 months. Satisfactory results were obtained in terms of functional and esthetic aspects. Evaluation of the data derived from the clinical and radiologic measurements revealed no permanent articular surface damage. K-wire fixation was documented to be an invaluable therapeutic approach not only to prevent recurrence of the contracture deformity but also to stabilize the skin graft effectively. This technique was concluded to provide effective immobilization without permanent articular damage.

Limb lengthening over plate

PubMed Central

Kulkarni, Ruta; Singh, Nishant; Kulkarni, Govind S; Kulkarni, Milind; Kulkarni, Sunil; Kulkarni, Vidisha

2012-01-01

Background: The limb lengthening over plate eliminates the associated risk of infection with limb lengthening over intramedullary nail. We present our experience of limb lengthening in 15 patients with a plate fixed on the proximal segment, followed by corticotomy and application of external fixator. Materials and Methods: 15 patients (7 females, 8 males) were included in this consecutive series. The average age was 18.1 years (range 8–35 years). Fifteen tibiae and one femur were lengthened in 15 patients. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. Results: The preoperative target length was successfully achieved in all patients at a mean of 4.1 cm (range 1.8–6.5 cm). The mean duration of external fixation was 75.3 days (range 33–116 days) with the mean external fixation index at 19.2 days/cm (range 10.0–38.3 days/cm). One patient suffered deep infection up to the plate, three patients had mild procurvatum deformities, and one patient developed mild tendo achilles contracture. Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis. PMID:22719123

[Sacral gigantocellular tumor treated with total sacrectomy and spinal-pelvic fixation].

PubMed

Savić, Milenko

2011-09-01

Total sacrectomy with spinal-pelvic fixation is considered to be a successful approach to the radical surgical treatment of extensive sacral tumors, however, technically very demanding, thus only rarely reported in the literature. We presented a patient with sacral gigantocellular tumor managed successfully using this method but with certain standard operative techniques improvements. A 30-year old patient with a pronounced painful syndrome and sphincter disorders was confirmed to have sacral gigantocellular tumor affecting a greater part of the sacrum. Tumor resection was performed in the first act out off retroperitoneal organs (colon and blood vessels), sacroiliac joints were open by the ventral side, the L5 discus removed, the S2-S5 roots cut off. In the second act, performed three weeks later, sacrectomy was completed by the reconstruction of pelvic ring and spinal-pelvic fixation. Then, the standard technique was modified to provide additional spinal fixation. The results of the operation (duration, blood loss, postoperative deficit) were quite comparable with, and in some aspects even better than the results published in the literature. Total sacrectomy with spinal-pelvic fixation can be a therapy of choice in patients with extensive sacral tumors requaring, however, the multidisciplinary approach and a considerable experience with instrumental spinal stabilization.

Arthroscopic evaluation for omalgia patients undergoing the clavicular hook plate fixation of distal clavicle fractures

PubMed Central

2014-01-01

Background The aim of this study is to investigate the anatomic changes in the shoulder joints responsible for omalgia after the clavicular hook plate fixation under arthroscope. Methods Arthroscopic examination was carried out for 12 omalgia patients who underwent clavicular hook plate fixation due to distal clavicle fractures. Functional outcome of shoulder was measured by the Japanese Orthopaedic Association (JOA) score before and after the withdrawal of the fixation plate. Results The rotator cuff compression by the clavicular hook was arthroscopically observed in 11 of the 12 cases. The JOA scores of the shoulder were significantly improved at 1 month after the withdrawal of the fixation plate (pain, 28 ± 2.4 vs. 15 ± 5.2; function, 19.2 ± 1.0 vs. 11.7 ± 1.9; range of movements, 26.8 ± 2.6 vs. 14.8 ± 3.4) compared with before. Conclusions The impingement of the hook to the rotator cuff may be the main cause for the omalgia. The appropriate hook and plate that fit to the curve of the clavicle as well as the acromion are necessary to decrease the severity of omalgia. PMID:24917508

Resorbable bone fixation alloys, forming, and post-fabrication treatments.

PubMed

Ibrahim, Hamdy; Esfahani, Sajedeh Nasr; Poorganji, Behrang; Dean, David; Elahinia, Mohammad

2017-01-01

Metallic alloys have been introduced as biodegradable metals for various biomedical applications over the last decade owing to their gradual corrosion in the body, biocompatibility and superior strength compared to biodegradable polymers. Mg alloys possess advantageous properties that make them the most extensively studied biodegradable metallic material for orthopedic applications such as their low density, modulus of elasticity, close to that of the bone, and resorbability. Early resorption (i.e., <3months) and relatively inadequate strength are the main challenges that hinder the use of Mg alloys for bone fixation applications. The development of resorbable Mg-based bone fixation hardware with superior mechanical and corrosion performance requires a thorough understanding of the physical and mechanical properties of Mg alloys. This paper discusses the characteristics of successful Mg-based skeletal fixation hardware and the possible ways to improve its properties using different methods such as mechanical and heat treatment processes. We also review the most recent work pertaining to Mg alloys and surface coatings. To this end, this paper covers (i) the properties and development of Mg alloys and coatings with an emphasis on the Mg-Zn-Ca-based alloys; (ii) Mg alloys fabrication techniques; and (iii) strategies towards achieving Mg-based, resorbable, skeletal fixation devices. Copyright © 2016 Elsevier B.V. All rights reserved.

Suture versus tack fixation of mesh in laparoscopic umbilical hernia repair.

PubMed

Kitamura, Riley K; Choi, Jacqueline; Lynn, Elizabeth; Divino, Celia M

2013-01-01

Mesh fixation in laparoscopic umbilical hernia repair is poorly studied. We compared postoperative outcomes of laparoscopic umbilical hernia repair in suture versus tack mesh fixation. Patients who underwent laparoscopic umbilical hernia repair were separated by method of mesh fixation: sutures versus primarily tacks. Medical history and follow-up data were collected through medical records. The primary outcome of this study was the recurrence rates of hernias. Postoperative major and minor complications, such as surgical site infection, small-bowel obstruction, and seroma formation, were regarded as secondary outcomes. Additionally, a telephone interview was conducted to assess postoperative pain, recovery time, and overall patient satisfaction. Eighty-six patients were identified: 33 in the suture group and 53 in the tacks group. The number of emergent cases was increased in the tacks group (6 vs 0; P = .022). Mean follow-up time was 2.7 years for both groups. Documented postoperative follow-up was obtained in 29 (90%) suture group and 31 (58%) tacks group patients. Hernia recurrence occurred in 3 and 2 patients in the sutures and tacks groups, respectively (P was not significant). No differences were found in secondary outcomes, including subjective outcomes from telephone interviews, between groups. There are no differences in postoperative complication rates in suture versus tack mesh fixation in laparoscopic umbilical hernia repair.

Line tension effects on the wetting of nanostructures: an energy method

NASA Astrophysics Data System (ADS)

Guo, Hao-Yuan; Li, Bo; Feng, Xi-Qiao

2017-09-01

The superhydrophobicity and self-cleaning property of micro/nano-structured solid surfaces require a stable Cassie-Baxter (CB) wetting state at the liquid-solid interface. We present an energy method to investigate how the three-phase line tension affects the CB wetting state on nanostructured materials. For some nanostructures, the line tension may engender a distinct energy barrier, which restricts the position of the three-phase contact line and affects the stability of the CB wetting state. We ascertain the upper and lower limits of the critical pressure at the CB-Wenzel transition. Our results suggest that superhydrophobicity on nanostructures can be modulated by tailoring the line tension and harnessing the curvature effect. This study also provides new insights into the sinking phenomena observed in the nanoparticle-floating experiment.

Micropores and methods of making and using thereof

DOEpatents

Perroud, Thomas D.; Patel, Kamlesh D.; Meagher, Robert J.

2016-08-02

Disclosed herein are methods of making micropores of a desired height and/or width between two isotropic wet etched features in a substrate which comprises single-level isotropic wet etching the two features using an etchant and a mask distance that is less than 2.times. a set etch depth. Also disclosed herein are methods using the micropores and microfluidic devices comprising the micropores.

A geometric method for computing ocular kinematics and classifying gaze events using monocular remote eye tracking in a robotic environment.

PubMed

Singh, Tarkeshwar; Perry, Christopher M; Herter, Troy M

2016-01-26

Robotic and virtual-reality systems offer tremendous potential for improving assessment and rehabilitation of neurological disorders affecting the upper extremity. A key feature of these systems is that visual stimuli are often presented within the same workspace as the hands (i.e., peripersonal space). Integrating video-based remote eye tracking with robotic and virtual-reality systems can provide an additional tool for investigating how cognitive processes influence visuomotor learning and rehabilitation of the upper extremity. However, remote eye tracking systems typically compute ocular kinematics by assuming eye movements are made in a plane with constant depth (e.g. frontal plane). When visual stimuli are presented at variable depths (e.g. transverse plane), eye movements have a vergence component that may influence reliable detection of gaze events (fixations, smooth pursuits and saccades). To our knowledge, there are no available methods to classify gaze events in the transverse plane for monocular remote eye tracking systems. Here we present a geometrical method to compute ocular kinematics from a monocular remote eye tracking system when visual stimuli are presented in the transverse plane. We then use the obtained kinematics to compute velocity-based thresholds that allow us to accurately identify onsets and offsets of fixations, saccades and smooth pursuits. Finally, we validate our algorithm by comparing the gaze events computed by the algorithm with those obtained from the eye-tracking software and manual digitization. Within the transverse plane, our algorithm reliably differentiates saccades from fixations (static visual stimuli) and smooth pursuits from saccades and fixations when visual stimuli are dynamic. The proposed methods provide advancements for examining eye movements in robotic and virtual-reality systems. Our methods can also be used with other video-based or tablet-based systems in which eye movements are performed in a peripersonal plane with variable depth.

Exposure of the surgeon's hands to radiation during hand surgery procedures.

PubMed

Żyluk, Andrzej; Puchalski, Piotr; Szlosser, Zbigniew; Dec, Paweł; Chrąchol, Joanna

2014-01-01

The objective of the study was to assess the time of exposure of the surgeon's hands to radiation and calculate of the equivalent dose absorbed during surgery of hand and wrist fractures with C-arm fluoroscope guidance. The necessary data specified by the objective of the study were acquired from operations of 287 patients with fractures of fingers, metacarpals, wrist bones and distal radius. 218 operations (78%) were percutaneous procedures and 60 (22%) were performed by open method. Data on the time of exposure and dose of radiation were acquired from the display of the fluoroscope, where they were automatically generated. These data were assigned to the individual patient, type of fracture, method of surgery and the operating surgeon. Fixations of distal radial fractures required longer times of radiation exposure (mean 61 sec.) than fractures of the wrist/metacarpals and fingers (38 and 32 sec., respectively), which was associated with absorption of significantly higher equivalent doses. Fixations of distal radial fractures by open method were associated with statistically significantly higher equivalent doses (0.41 mSv) than percutaneous procedures (0.3 mSv). Fixations of wrist and metacarpal bone fractures by open method were associated with lower equivalent doses (0.34 mSv) than percutaneous procedures (0.37 mSv),but the difference was not significant. Fixations of finger fractures by open method were associated with lower equivalent doses (0.13 mSv) than percutaneous procedures (0.24 mSv), the difference being statistically non-significant. Statistically significant differences in exposure time and equivalent doses were noted between 4 surgeons participating in the study, but no definitive relationship was found between these parameters and surgeons' employment time. 1. Hand surgery procedures under fluoroscopic guidance are associated with mild exposure of the surgeons' hands to radiation. 2. The equivalent dose was related to the type of fracture, operative technique and - to some degree - to the time of employment of the surgeon.

Outcomes of Pin and Plaster Versus Locking Plate in Distal Radius Intraarticular Fractures

PubMed Central

Bahari-Kashani, Mahmoud; Taraz-Jamshidy, Mohammad Hosein; Rahimi, Hassan; Ashraf, Hami; Mirkazemy, Masoud; Fatehi, Amirreza; Asadian, Mariam; Rezazade, Jafar

2013-01-01

Background Distal radius fractures are among the most prevalent fractures predictive of probable occurrence of other osteoporotic fractures. They are treated via a variety of methods, but the best treatment has not been defined yet. Objectives This study was performed to compare the results of open reduction and internal fixation with locking plates versus the pin and plaster method. Materials and Methods In this prospective study, 114 patients aged 40 to 60 years with Fernandez type III fracture referring to Imam-Reza and Mehr hospitals of Mashhad from 2009 to 2011, were selected randomly; after obtaining informed consent, they were treated with pin and plaster fixation (n = 57) or internal fixation with the volar locking plate (n = 57). They were compared at the one year follow up. Demographic features and standard radiographic indices were recorded and MAYO, DASH and SF - 36 tests were performed. Data was analyzed by SPSS software version 13, with descriptive indices, Mann-Whitney and Chi-square tests. Results SF-36 test demonstrated a better general health (P < 0.001), mental health (P = 0.006), physical functioning (P < 0.001), social functioning (P < 0.001) and energy/fatigue (P < 0.001) in LCP group. However, pain (P = 0.647) was not significantly different between the groups. Physical limitation (P < 0.001) and emotional limitation (P < 0.001) were greater in the pin and plaster group. Also, in the LCP group mean MAYO score (P < 0.001) was more than pin and plaster group. Mean DASH score was not different between the groups (P = 0.218). The rate of acceptable results of radiographic indices (P < 0.001), grip strength (P < 0.001) and range of motion in supination-pronation (P < 0.001) in LCP method were better than the pin and plaster method. Conclusions In treatment of intra-articular distal radius fractures in middle-aged patients internal fixation with locking plates may be prefered to pin and plaster as the treatment of choice. PMID:24350132

Extraction and functional properties of non-zein proteins in corn germ from wet-milling

USDA-ARS?s Scientific Manuscript database

This study was conducted to develop methods of extracting corn germ protein and characterize and identify potential applications of the recovered protein. Protein was extracted from both wet germ and finished (dried) germ using 0.1M NaCl as solvent. The method involved homogenization, stirring, cent...

Flame Stabilization on Microscopic Scale of Wet Biogas with Microflame

NASA Astrophysics Data System (ADS)

Ida, Tamio; Fuchihata, Manabu; Mizuno, Satoru

Harvesting, transportation, energy conversion and the high-efficient utilization, cascade method and market formation besides become with the indispensable element in order to utilize the biomass resource. There are two type biogases; it is gasified gas from dried biomass by partially combustion and wet biogas from wet biomass by methane fermentation, especially from the livestock excrement resources. This paper discusses an experimental study for flame stabilization on microscopic scale with wet biogas (mainly 0.6CH4+0.4CO2). In this study, the microflame with the wet biogas fuels are formed by the diffusion flame on the coppered straight pipes of inner diameter 0.02mm ˜ 1.5mm. This study is obtained stability mapping on microscopic scale of formed microflame by wet biogas fuels. The flame stability limit conditions on microscopic scale of wet biogas is drawn with blow off and extinction flame double limit lines. It is suggested that minimum mixing spatial scale change by the each mixing ratio of the wet biogas.

The management of abdominal wall hernias – in search of consensus

PubMed Central

Bury, Kamil; Śmietański, Maciej

2015-01-01

Introduction Laparoscopic repair is becoming an increasingly popular alternative in the treatment of abdominal wall hernias. In spite of numerous studies evaluating this technique, indications for laparoscopic surgery have not been established. Similarly, implant selection and fixation techniques have not been unified and are the subject of scientific discussion. Aim To assess whether there is a consensus on the management of the most common ventral abdominal wall hernias among recognised experts. Material and methods Fourteen specialists representing the boards of European surgical societies were surveyed to determine their choice of surgical technique for nine typical primary ventral and incisional hernias. The access method, type of operation, mesh prosthesis and fixation method were evaluated. In addition to the laparoscopic procedures, the number of tackers and their arrangement were assessed. Results In none of the cases presented was a consensus of experts obtained. Laparoscopic and open techniques were used equally often. Especially in the group of large hernias, decisions on repair methods were characterised by high variability. The technique of laparoscopic mesh fixation was a subject of great variability in terms of both method selection and the numbers of tackers and sutures used. Conclusions Recognised experts have not reached a consensus on the management of abdominal wall hernias. Our survey results indicate the need for further research and the inclusion of large cohorts of patients in the dedicated registries to evaluate the results of different surgical methods, which would help in the development of treatment algorithms for surgical education in the future. PMID:25960793

Cold Pad-Batch dyeing method for cotton fabric dyeing with reactive dyes using ultrasonic energy.

PubMed

Khatri, Zeeshan; Memon, Muhammad Hanif; Khatri, Awais; Tanwari, Anwaruddin

2011-11-01

Reactive dyes are vastly used in dyeing and printing of cotton fibre. These dyes have a distinctive reactive nature due to active groups which form covalent bonds with -OH groups of cotton through substitution and/or addition mechanism. Among many methods used for dyeing cotton with reactive dyes, the Cold Pad Batch (CPB) method is relatively more environment friendly due to high dye fixation and non requirement of thermal energy. The dyed fabric production rate is low due to requirement of at least twelve hours batching time for dye fixation. The proposed CPB method for dyeing cotton involves ultrasonic energy resulting into a one third decrease in batching time. The dyeing of cotton fibre was carried out with CI reactive red 195 and CI reactive black 5 by conventional and ultrasonic (US) method. The study showed that the use of ultrasonic energy not only shortens the batching time but the alkalis concentrations can considerably be reduced. In this case, the colour strength (K/S) and dye fixation (%F) also enhances without any adverse effect on colour fastness of the dyed fabric. The appearance of dyed fibre surface using scanning electron microscope (SEM) showed relative straightening of fibre convolutions and significant swelling of the fibre upon ultrasonic application. The total colour difference values ΔE (CMC) for the proposed method, were found within close proximity to the conventionally dyed sample. Copyright © 2011 Elsevier B.V. All rights reserved.

Biomechanical stability of a supra-acetabular pedicle screw internal fixation device (INFIX) vs external fixation and plates for vertically unstable pelvic fractures.

PubMed

Vigdorchik, Jonathan M; Esquivel, Amanda O; Jin, Xin; Yang, King H; Onwudiwe, Ndidi A; Vaidya, Rahul

2012-09-27

We have recently developed a subcutaneous anterior pelvic fixation technique (INFIX). This internal fixator permits patients to sit, roll over in bed and lie on their sides without the cumbersome external appliances or their complications. The purpose of this study was to evaluate the biomechanical stability of this novel supraacetabular pedicle screw internal fixation construct (INFIX) and compare it to standard internal fixation and external fixation techniques in a single stance pelvic fracture model. Nine synthetic pelves with a simulated anterior posterior compression type III injury were placed into three groups (External Fixator, INFIX and Internal Fixation). Displacement, total axial stiffness, and the stiffness at the pubic symphysis and SI joint were calculated. Displacement and stiffness were compared by ANOVA with a Bonferroni adjustment for multiple comparisons The mean displacement at the pubic symphysis was 20, 9 and 0.8 mm for external fixation, INFIX and internal fixation, respectively. Plate fixation was significantly stiffer than the INFIX and external Fixator (P = 0.01) at the symphysis pubis. The INFIX device was significantly stiffer than external fixation (P = 0.017) at the symphysis pubis. There was no significant difference in SI joint displacement between any of the groups. Anterior plate fixation is stiffer than both the INFIX and external fixation in single stance pelvic fracture model. The INFIX was stiffer than external fixation for both overall axial stiffness, and stiffness at the pubic symphysis. Combined with the presumed benefit of minimizing the complications associated with external fixation, the INFIX may be a more preferable option for temporary anterior pelvic fixation in situations where external fixation may have otherwise been used.

Wet/dry cooling tower and method

DOEpatents

Glicksman, Leon R.; Rohsenow, Warren R.

1981-01-01

A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

Binderless fiberboard from two different types of fiber furnishes

Treesearch

Otto Suchsland; George Woodson; Charles W. McMillin

1985-01-01

Fiber furnishes from two commercial processes were used to make experimental hardboards by all four possible methods: wet formed (pressed dry and wet), and dry formed (pressed dry and wet). Since no adhesives were added, all bonding was due to natural agents. Results of mechanical and physical testing of the hardboards indicated that high quality hardboard can be made...

Eye movement assessment of selective attentional capture by emotional pictures.

PubMed

Nummenmaa, Lauri; Hyönä, Jukka; Calvo, Manuel G

2006-05-01

The eye-tracking method was used to assess attentional orienting to and engagement on emotional visual scenes. In Experiment 1, unpleasant, neutral, or pleasant target pictures were presented simultaneously with neutral control pictures in peripheral vision under instruction to compare pleasantness of the pictures. The probability of first fixating an emotional picture, and the frequency of subsequent fixations, were greater than those for neutral pictures. In Experiment 2, participants were instructed to avoid looking at the emotional pictures, but these were still more likely to be fixated first and gazed longer during the first-pass viewing than neutral pictures. Low-level visual features cannot explain the results. It is concluded that overt visual attention is captured by both unpleasant and pleasant emotional content. 2006 APA, all rights reserved

Biomechanical Evaluation of All-Polyethylene Pegged Bony Ingrowth Glenoid Fixation Techniques on Implant Micromotion.

PubMed

Wiater, Brett P; Moravek, James E; Kurdziel, Michael D; Baker, Kevin C; Wiater, J Michael

2016-01-01

Newer glenoid components that allow for hybrid cement fixation via traditional cementation of peripheral pegs and bony ingrowth into an interference-fit central peg introduce the possibility of long-term biological fixation. However, little biomechanical work has been done on the initial stability of these components and the various fixation options. We conducted a study in which all-polyethylene glenoid components with a centrally fluted peg were implanted in polyurethane blocks with interference-fit, hybrid cement, and fully cemented fixation (5 per fixation group). Biomechanical evaluation of glenoid loosening, according to ASTM Standard F-2028-12, subjected the glenoids to 50,000 cycles of rim loading, and glenoid component motion was recorded with 2 differential variable reluctance transducers fixed to each glenoid prosthesis. Fully cemented fixation exhibited significantly less mean distraction in comparison with interference-fit fixation (P < .001) and hybrid cement fixation (P < .001). Hybrid cement fixation exhibited significantly less distraction (P < .001), more compression (P < .001), and no significant difference in glenoid translation (P = .793) in comparison with interference-fit fixation. Fully cemented fixation exhibited the most resistance to glenoid motion in comparison with hybrid cement fixation and interference-fit fixation. However, hybrid cement fixation and interference-fit fixation exhibited equivocal motion. Given these results, cementation of peripheral pegs may confer no additional initial stability over that provided by uncemented interference-fit fixation.

Proximal humeral fractures: the role of calcium sulphate augmentation and extended deltoid splitting approach in internal fixation using locking plates.

PubMed

Somasundaram, K; Huber, C P; Babu, V; Zadeh, H

2013-04-01

The aim of our study is to analyse the results of our surgical technique for the treatment of proximal humeral fractures and fracture dislocations using locking plates in conjunction with calcium sulphate bone-substitute augmentation and tuberosity repair using high-strength sutures. We used the extended deltoid-splitting approach for fracture patterns involving displacement of both lesser and greater tuberosities and for fracture-dislocations. Optimal surgical management of proximal humeral fractures remains controversial. Locking plates have become a popular method of fixation. However, failure of fixation may occur if they are used as the sole method of fixation in comminuted fractures, especially in osteopenic bone. We retrospectively analysed 22 proximal humeral fractures in 21 patients; 10 were male and 11 female with an average age of 64.6 years (range 37-77). Average follow-up was 24 months. Eleven of these fractures were exposed by the extended deltoid-splitting approach. Fractures were classified according to Neer and Hertel systems. Preoperative radiographs and computed tomography (CT) scans in three- and four-part fractures were done to assess the displacement and medial calcar length for predicting the humeral head vascularity. According to the Neer classification, there were five two-part, six three-part, five four-part fractures and six fracture-dislocations (two anterior and four posterior). Results were assessed clinically with disabilities of the arm, shoulder and hand (DASH) scores, modified Constant and Murley scores and serial postoperative radiographs. The mean DASH score was 16.18 and the modified Constant and Murley score was 64.04 at the last follow-up. Eighteen out of twenty-two cases achieved good clinical outcome. All the fractures united with no evidence of infection, failure of fixation, malunion, tuberosity failure, avascular necrosis or adverse reaction to calcium sulphate bone substitute. There was no evidence of axillary nerve injury. Four patients had a longer recovery period due to stiffness, associated wrist fracture and elbow dislocation. The CaSO4 bone substitute was replaced by normal appearing trabecular bone texture at an average of 6 months in all patients. In our experience, we have found the use of locking plates, calcium sulphate bone substitute and tuberosity repair with high-strength sutures to be a safe and reliable method of internal fixation for complex proximal humeral fractures and fracture-dislocations. Furthermore, we have also found the use of the extended deltoid-splitting approach to be safe and to provide excellent exposure facilitating accurate reduction for fixation of the fracture patterns involving displacement of both lesser and greater tuberosities and for fracture-dislocations. Copyright © 2012 Elsevier Ltd. All rights reserved.

The method of neutron imaging as a tool for the study of the dynamics of water movement in wet aramid-based ballistic body armour panels

NASA Astrophysics Data System (ADS)

Reifler, Felix A.; Lehmann, Eberhard H.; Frei, Gabriel; May, Hans; Rossi, René

2006-07-01

A new non-destructive method based on neutron imaging (neutron radiography) to determine the exact water content in aramid-based soft body armour panels is presented. While investigating the ballistic resistance of aramid-based body armour panels under a wet condition, it is important to precisely determine their water content and its chronological development. Using the presented method, the influence of water amount and location on impact testing as well as its time dependence was shown. In the ballistic panels used, spreading of water strongly depended on the kind of quilting. Very fast water migration could be observed when the panels were held vertically. Some first results regarding the water distribution in wet panels immediately after the impact are presented. On the basis of the presented results, requirements for a standard for testing the performance of ballistic panels in the wet state are deduced.

Determination of the critical surface tension of wetting of minerals treated with surfactants by shear flocculation approach.

PubMed

Ozkan, A

2004-09-15

This paper contributes the shear flocculation method as a new approach to determine the critical surface tension of wetting of minerals treated with surfactants. This newly developed approach is based on the decrease of the shear flocculation of the mineral suspension, with decreasing of the surface tension of the liquids used. The solution surface tension value at which shear flocculation does not occur can be defined as the critical surface tension of wetting (gamma c) of the mineral. By using the shear flocculation method, the critical surface tensions of wetting (gamma c) for calcite and barite minerals, treated with surfactants, were obtained as 30.9 and 35.0 mN/m, respectively. These values are in good agreement with data reported previously on the same minerals obtained by the contact angle measurement and flotation methods. The chemical agents used for the treatment of calcite and barite particles were sodium oleate and sodium dodecyl sulfate, respectively.

Nanoporous carbon actuator and methods of use thereof

DOEpatents

Biener, Juergen [San Leandro, CA; Baumann, Theodore F [Discovery Bay, CA; Shao, Lihua [Karlsruhe, DE; Weissmueller, Joerg [Stutensee, DE

2012-07-31

An electrochemically driveable actuator according to one embodiment includes a nanoporous carbon aerogel composition capable of exhibiting charge-induced reversible strain when wetted by an electrolyte and a voltage is applied thereto. An electrochemically driven actuator according to another embodiment includes a nanoporous carbon aerogel composition wetted by an electrolyte; and a mechanism for causing charge-induced reversible strain of the composition. A method for electrochemically actuating an object according to one embodiment includes causing charge-induced reversible strain of a nanoporous carbon aerogel composition wetted with an electrolyte to actuate the object by the strain.

Wet-chemical systems and methods for producing black silicon substrates

DOEpatents

Yost, Vernon; Yuan, Hao-Chih; Page, Matthew

2015-05-19

A wet-chemical method of producing a black silicon substrate. The method comprising soaking single crystalline silicon wafers in a predetermined volume of a diluted inorganic compound solution. The substrate is combined with an etchant solution that forms a uniform noble metal nanoparticle induced Black Etch of the silicon wafer, resulting in a nanoparticle that is kinetically stabilized. The method comprising combining with an etchant solution having equal volumes acetonitrile/acetic acid:hydrofluoric acid:hydrogen peroxide.

Floor cleaning: effect on bacteria and organic materials in hospital rooms.

PubMed

Andersen, B M; Rasch, M; Kvist, J; Tollefsen, T; Lukkassen, R; Sandvik, L; Welo, A

2009-01-01

Routine surface cleaning is recommended to control the spread of pathogens in hospital environments. In Norway, ordinary cleaning of patient rooms is traditionally performed with soap and water. In this study, four floor-mopping methods--dry, spray, moist and wet mopping--were compared by two systems using adenosine triphosphate (ATP) bioluminescence (Hygiena and Biotrace). These systems assess residual organic soil on surfaces. The floor-mopping methods were also assessed by microbiological samples from the floor and air, before and after cleaning. All methods reduced organic material on the floors but wet and moist mopping seemed to be the most effective (P < 0.001, P < 0.011, respectively, ATP Hygiena). The two ATP methods were easy to use, although each had their own reading scales. Cleaning reduced organic material to 5-36% of the level present before cleaning, depending upon mopping method. All four mopping methods reduced bacteria on the floor from about 60-100 to 30-60 colony-forming units (cfu)/20cm2 floor. Wet, moist and dry mopping seemed to be more effective in reducing bacteria on the floor, than the spray mopping (P=0.007, P=0.002 and P=0.011, respectively). The burden of bacteria in air increased for all methods just after mopping. The overall best cleaning methods seemed to be moist and wet mopping.

Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach.

PubMed

Dong, Tao; Yu, Liang; Gao, Difeng; Yu, Xiaochen; Miao, Chao; Zheng, Yubin; Lian, Jieni; Li, Tingting; Chen, Shulin

2015-12-01

Accurate determination of fatty acid contents is routinely required in microalgal and yeast biofuel studies. A method of rapid in situ fatty acid methyl ester (FAME) derivatization directly from wet fresh microalgal and yeast biomass was developed in this study. This method does not require prior solvent extraction or dehydration. FAMEs were prepared with a sequential alkaline hydrolysis (15 min at 85 °C) and acidic esterification (15 min at 85 °C) process. The resulting FAMEs were extracted into n-hexane and analyzed using gas chromatography. The effects of each processing parameter (temperature, reaction time, and water content) upon the lipids quantification in the alkaline hydrolysis step were evaluated with a full factorial design. This method could tolerate water content up to 20% (v/v) in total reaction volume, which equaled up to 1.2 mL of water in biomass slurry (with 0.05-25 mg of fatty acid). There were no significant differences in FAME quantification (p>0.05) between the standard AOAC 991.39 method and the proposed wet in situ FAME preparation method. This fatty acid quantification method is applicable to fresh wet biomass of a wide range of microalgae and yeast species.

Statistical dependency in visual scanning

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.; Stark, Lawrence

1986-01-01

A method to identify statistical dependencies in the positions of eye fixations is developed and applied to eye movement data from subjects who viewed dynamic displays of air traffic and judged future relative position of aircraft. Analysis of approximately 23,000 fixations on points of interest on the display identified statistical dependencies in scanning that were independent of the physical placement of the points of interest. Identification of these dependencies is inconsistent with random-sampling-based theories used to model visual search and information seeking.

Scapulothoracic dissociation with acromioclavicular separation: a case report of a novel fixation method.

PubMed

Merk, Bradley R; Minihane, Keith P; Shah, Nirav A

2008-09-01

We present a case of 39-year-old female with a scapulothoracic dissociation and acromioclavicular (AC) separation and who had fixation of the AC joint with a locking plate, coracoclavicular screw, and transarticular AC screw. The coracoclavicular and AC relationships were maintained during postoperative rehabilitation and after hardware removal. Use of a locking plate can lead to good functional outcome without the complications associated with the use of pin and wire constructs or without violating the subacromial space.

An improved method for cable grip fixation of the greater trochanter after trochanteric slide osteotomy.

PubMed

Thakur, Nikhil A; Crisco, Joseph J; Moore, Douglas C; Froehlich, John A; Limbird, Richard S; Bliss, James M

2010-02-01

This study proposes a novel method for reattachment of the trochanteric slide osteotomy. The strength of this new fixation system was compared to established configurations. Fifteen sawbone femurs were used. Our configuration used cables above and below the lesser trochanter with a third cable around the shaft of the femur while passing the loose ends through the inferior hole of the cable grip. Displacement of the trochanter was measured with increasing load. Force required for catastrophic failure was also measured. The 3-cable construct resulted in significantly less displacement with increasing load and required a larger force to cause failure (1 cm and 2 cm). We theorize that our configuration produces a biomechanically stronger construct than previously used methods. 2010 Elsevier Inc. All rights reserved.

A review on color normalization and color deconvolution methods in histopathology.

PubMed

Onder, Devrim; Zengin, Selen; Sarioglu, Sulen

2014-01-01

The histopathologists get the benefits of wide range of colored dyes to have much useful information about the lesions and the tissue compositions. Despite its advantages, the staining process comes up with quite complex variations in staining concentrations and correlations, tissue fixation types, and fixation time periods. Together with the improvements in computing power and with the development of novel image analysis methods, these imperfections have led to the emerging of several color normalization algorithms. This article is a review of the currently available digital color normalization methods for the bright field histopathology. We describe the proposed color normalization methodologies in detail together with the lesion and tissue types used in the corresponding experiments. We also present the quantitative validation approaches for each of the proposed methodology where available.

An Improved Method for Cable Grip Fixation of the Greater Trochanter After Trochanteric Slide Osteotomy

PubMed Central

Thakur, Nikhil A.; Crisco, Joseph J.; Moore, Douglas C.; Froehlich, John A.; Limbird, Richard S.; Bliss, James M.

2017-01-01

This study proposes a novel method for reattachment of the trochanteric slide osteotomy. The strength of this new fixation system was compared to established configurations. Fifteen sawbone femurs were used. Our configuration used cables above and below the lesser trochanter with a third cable around the shaft of the femur while passing the loose ends through the inferior hole of the cable grip. Displacement of the trochanter was measured with increasing load. Force required for catastrophic failure was also measured. The 3-cable construct resulted in significantly less displacement with increasing load and required a larger force to cause failure (1 cm and 2 cm). We theorize that our configuration produces a biomechanically stronger construct than previously used methods. PMID:19062247

The effectiveness of wet cupping vs. venesection on arterial O2 saturation level of cigarette smokers: A randomized controlled clinical trial

PubMed Central

D, Hekmatpou; L, Moeini; S, Haji-Nadali

2013-01-01

Objective: Wet cupping is a traditional bloodletting method recommended for controlling of respiratory disease complications. This study aimed to compare the efficacy of wet cupping vs. venesection on arterial O2 saturation level of smokers. Methods: This is a randomized controlled clinical trial which started with simple sampling of smokers. After administering spirometery, participants (N = 110 male smokers) with positive pulmonary function test (PFT), who manifested Chronic Obstructive Pulmonary Disease (COPD), were randomly assigned to intervention and control groups. The two groups were assessed in terms of demographic data, rate of hemoglobin (Hb), hematocrit (Hct), and arterial O2 saturation. Then, the intervention participants underwent wet cupping whereas venesection was performed on the control participants. At four stages after the two treatments, pulse oximetery was performed. Data was analyzed using SPSS (Version 17). Results: Result shows that mean arterial O2 sat level increased at three stages, namely before, immediately after, and 6 and 12 hrs after these two treatments (p ≤ 0.001). This indicates that wet cupping and venesection alike were effective on O2 sat level in the two groups, but the increasing pattern was maintained 12 hrs afterward only in those participants who had received wet cupping (p ≤ 0.001). Moreover, the results of repeated measure ANOVA between the two groups at the four stages showed that there were significant differences between the means of O2 saturation level at the 6- and 12-hrs stages (F = 66.92, p ≤ 0.001). Conclusion: Wet cupping caused a continued O2 saturation in the intervention group even up to 12 hrs afterward. Participants expressed liveliness and improved respiration after wet cupping. Therefore, wet cupping is recommended for promoting the health of cigarette smokers. PMID:24550951

Controls on net carbon accumulation in North American peatlands: Insights from 210Pb dated cores

NASA Astrophysics Data System (ADS)

Wieder, R.; Scott, K. D.; Vile, M. A.; Vitt, D. H.; Burke-Scoll, M.

2012-12-01

Northern peatlands cover only 3-4 % of the Earth's land surface area, yet store hugh quantities (250-450 Pg) of carbon as peat. These peatlands generally are believed to function as net sinks for atmospheric CO2 today, with C fixation by net primary production at the peat surface exceeding C losses by organic matter mineralization throughout the peat column. Various aspects of peatland structure and function are influenced by a variety of factors, including local climatic conditions and atmospheric deposition of N and S. Here we examine continental-scale patterns in recent net C accumulation in peatlands across North America, combining the published data for eastern Canada from Moore et al. (2004, Global Change Biology) and Turunen et al. (2004, Global Biogeochemical Cycles) with our data from boreal sites in western Canada (Alberta) and from temperate sites in the U.S. Across these sites, mean annual, January, and July temperatures ranged from 0.6 to 9.1, -20.5 to -1.6, and 11.3 to 20.8 oC, respecticely, mean annual precipitation, rainfall, and snowfall ranged from 406 to 1480, 289 to 1156 and 112 to 415 mm, respectively, growing degree days (above 5 oC) ranged from 947 to 4467, and annual wet N and S deposition ranged from 0.9 to 8.1 and 0.4 to 13.4 kg/ha/yr. For 67 cores, net C accumulation in peat over the past 50 years was determined by 210Pb dating and ranged from 492 to 1781 kg/ha/yr. Net C accumulation (kg/ha/yr) was positively correlated with mean annual precipitation (p = 0.0129), mean annual snowfall (p = 0.0010) and wet deposition of both N (p < 0.0001) and S (p = 0.0003). However, both the climatic and wet deposition variables exhibit similar gradients across North America, and hence are coufounded. Stepwise regression revealed that 53% of the overall variation in net C accumulation could be explained by only two variables, wet N deposition (p < 0.0001; R2 = 0.35) and mean annual temperature (p = 0.0106; R2 = 0.07), with the regression model of net C accumulation (kg/ha/yr) = 913 + (950 x wet N deposition) - (46 x mean annual temperature). The effects of ongoing climate change, notably warming and changing regional patterns of atmospheric N deposition, may have ramifications for peatland carbon cycling.

Stabilization study on a wet-granule tableting method for a compression-sensitive benzodiazepine receptor agonist.

PubMed

Fujita, Megumi; Himi, Satoshi; Iwata, Motokazu

2010-03-01

SX-3228, 6-benzyl-3-(5-methoxy-1,3,4-oxadiazol-2-yl)-5,6,7,8-tetrahydro-1,6-naphthyridin-2(1H)-one, is a newly-synthesized benzodiazepine receptor agonist intended to be developed as a tablet preparation. This compound, however, becomes chemically unstable due to decreased crystallinity when it undergoes mechanical treatments such as grinding and compression. A wet-granule tableting method, where wet granules are compressed before being dried, was therefore investigated as it has the advantage of producing tablets of sufficient hardness at quite low compression pressures. The results of the stability testing showed that the drug substance was chemically considerably more stable in wet-granule compression tablets compared to conventional tablets. Furthermore, the drug substance was found to be relatively chemically stable in wet-granule compression tablets even when high compression pressure was used and the effect of this pressure was small. After investigating the reason for this excellent stability, it became evident that near-isotropic pressure was exerted on the crystals of the drug substance because almost all the empty spaces in the tablets were occupied with water during the wet-granule compression process. Decreases in crystallinity of the drug substance were thus small, making the drug substance chemically stable in the wet-granule compression tablets. We believe that this novel approach could be useful for many other compounds that are destabilized by mechanical treatments.

Assessment of the Biomechanical Performance of 5 Plating Techniques in Fixation of Mandibular Subcondylar Fracture Using Finite Element Analysis.

PubMed

Darwich, Mhd Ayham; Albogha, Mhd Hassan; Abdelmajeed, Adnan; Darwich, Khaldoun

2016-04-01

The aim of this study was to compare the performances of 5 plating techniques for fixation of unilateral mandibular subcondylar fracture. Five titanium plating techniques for fixation of condylar fracture were analyzed using the finite element method. The modeled techniques were 1) 1 straight plate, 2) 2 parallel straight plates, 3) 2 angulated straight plates, 4) 1 trapezoidal plate, and 5) 1 square plate. Three-dimensional models were generated using patient-specific geometry for the mandible obtained from a computerized tomographic image of a healthy living man. Plates were designed and combined with the mandible and analyzed under a 500-N load. The single straight plate presented the most inferior performance; it presented maximum displacement and strain on cortical bone. The trapezoidal plate induced the least amount of strain on cortical bone and was best at resisting displacement. The trapezoidal plate is recommended for fixation of subcondylar fracture. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Application of 4-META/MMA-TBB resin for fixation of membrane to tooth in guided tissue regeneration in dog.

PubMed

Tomita, Sachiyo; Yamamoto, Shigeki; Shibukawa, Yoshihiro; Kaneko, Tadashi; Miyakoshi, Shoichi; Shimono, Masaki; Yamada, Satoru

2010-11-01

The aim of this study was to evaluate 4-META/MMA-TBB resin as an alternative to sling sutures for fixation of membrane to tooth in GTR in terms of its effect on tissue regeneration. Dehiscence periodontal defects were created in 6 dogs which were divided at random into two groups, 3 dogs in each group: an experimental group, in which non-absorbable or absorbable membrane was fixed to the teeth with 4-META/MMA-TBB resin; and a control group, in which sling sutures were applied to fix the two types of membrane. Histologic and histometric evaluation was carried out at 8 weeks post-operatively to determine healing response in each group. Both methods of achieving membrane fixation to tooth were effective in inhibiting epithelial migration and encouraging formation of regenerated periodontal tissues around the root surfaces. These results suggest that 4-META/MMA-TBB resin is as effective as sling sutures in achieving membrane fixation in GTR and is, moreover, easier to apply.

Biomechanical analysis of four different fixations for the posterolateral shearing tibial plateau fracture.

PubMed

Zhang, Wei; Luo, Cong-Feng; Putnis, Sven; Sun, Hui; Zeng, Zhi-Min; Zeng, Bing-Fang

2012-03-01

The posterolateral shearing tibial plateau fracture is uncommon in the literature, however with the increased usage of computer tomography (CT), the incidence of these fractures is no longer as low as previously thought. Few studies have concentrated on this fracture, least of all using a biomechanical model. The purpose of this study was to compare and analyse the biomechanical characteristics of four different types of internal fixation to stabilise the posterolateral shearing tibial plateau fracture. Forty synthetic tibiae (Synbone, right) simulated the posterolateral shearing fracture models and these were randomly assigned into four groups; Group A was fixed with two anterolateral lag screws, Group B with an anteromedial Limited Contact Dynamic Compression Plate (LC-DCP), Group C with a lateral locking plate, and Group D with a posterolateral buttress plate. Vertical displacement of the posterolateral fragment was measured using three different strengths of axial loading force, and finally loaded until fixation failure. It was concluded that the posterolateral buttress plate is biomechanically the strongest fixation method for the posterolateral shearing tibial plateau fracture. Copyright © 2011 Elsevier B.V. All rights reserved.

Polycaprolactone/glass bioabsorbable implant in a rabbit humerus fracture model.

PubMed

Lowry, K J; Hamson, K R; Bear, L; Peng, Y B; Calaluce, R; Evans, M L; Anglen, J O; Allen, W C

1997-09-15

Research in improved materials and methods for internal fixation has centered on internal fixators made of bioabsorbable materials such as polylactic acid, polyglycolic acid, and polyparadioxanone. These materials have two problems: the first is a postoperative complication related to a delayed inflammatory response; and the second is low strength characteristics. An alternative material developed to alleviate these problems is a composite of phosphate glass fibers embedded in the polymer polycaprolactone, referred to as PCL. In this study, intramedullary pins made of PCL were compared to stainless steel pins in a rabbit humerus osteotomy model. Specimens were harvested at 0, 6, and 12 weeks postoperatively, radiographs and mechanical testing to failure were performed at each time interval, and tissue was examined microscopically at 6 and 12 weeks. Histologic results showed PCL pins to be well tolerated with minimal inflammation around the pin. Mechanical testing revealed the PCL fixation to be weaker initially than the stainless steel fixation. There was significant stress shielding of stainless-steel-healed rabbit humeri when compared to the PCL/bone humeri. All osteotomies immobilized with PCL healed with abundant periosteal callus production.

Fixation Strategies For Retinal Immunohistochemistry

PubMed Central

Stradleigh, Tyler W.; Ishida, Andrew T.

2015-01-01

Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

Tibial plafond fractures: limited incision reduction with percutaneous fixation.

PubMed

Salton, Heather L; Rush, Shannon; Schuberth, John

2007-01-01

This study was a retrospective review of 18 patients with 19 pilon fractures treated with limited incision reduction and percutaneous plate fixation of the tibia. Patients were treated with either a 1- or 2-stage protocol. The latter consisted of placement of an external fixator followed by definitive reduction. The emphasis of analysis was placed on the identification of complications to the soft tissue envelope or bone-healing problems within the first 6 months after surgery. A major complication was defined as an unplanned operation within the first 6 months. Minor complications were any superficial wound defects that did not require operative intervention to resolve or any malunion or delayed union. With this protocol, no major complications were encountered. Minor complications were identified in 4 patients (4 fractures) of which 2 were minor wound problems. One patient developed a malunion, and the other had a delayed union. Four patients requested removal of prominent hardware. These results indicate that limited incision reduction and percutaneous plate fixation lead to safe methods of stabilization. The authors also provide guidance and strategies for the consistent execution of this technique.

The clinical application of absorbable intramedullary nail and claw plate on treating multiple rib fractures.

PubMed

Chai, X; Lin, Q; Ruan, Z; Zheng, J; Zhou, J; Zhang, J

2013-08-01

The absorption intramedullary nail and claw plate indications and efficacy were investigated in the treatment of a life-threatening multiple rib fractures. A retrospective analysis of 248 surgically treated rib fracture patients was performed who admitted to our hospital from March 2007 to December 2012. Intramedullary nailing was performed in 28 cases, a claw-type bone plate was fixed in 141 cases, and a combination of both was fixed in 79 cases. All internal fixation patients were clinically cured except 1 patient died 14 days after a massive pulmonary embolism. The patients with flail chest and floating chest wall causing respiratory and circulatory disorders were promptly corrected. Routine follow-up was from 1 to 2 years, displaced fractures were in 2 cases, and there were 11 cases of internal fixation and extraction. Internal fixation is a simple and reliable method for the treatment of multiple rib fractures. Both internal fixation materials have their pros and cons but the claw bone plate is more robust. The actual selection of appropriate treatment options helps to improve the treatment efficacy.

Use of C2 spinous process screw for posterior cervical fixation as substitute for laminar screw in a patient with thin laminae

PubMed Central

Nagata, Kosei; Baba, Satoshi; Chikuda, Hirotaka; Takeshita, Katsushi

2013-01-01

Rigid screw fixation of C2 including transarticular screw and pedicle screw contain the risk of vertebral artery (VA) injury. On the other hand, translaminar screws are considered to be safer for patients with anomalous VA. But C2 translaminar screw placement was limited in patients who have thin laminas and there is marked variation in C2 laminar thickness. Appropriate C2 fixation method for a patient who has thin laminas and high-riding VA together was controversial. Here, we present a case of an elderly Asian woman who had thin laminas and high-riding VA together with progressive myelopathy to report a first case of C2 spinous process screw insertion. Although the stability and safety of C2 spinous process screw was reported in cadaver series, there was no clinical report to our knowledge. Spinous process screw can be an option of C2 fixation for patients with high-riding VA and severe degenerated cervical spines including thin C2 laminas. PMID:23814004

Injectable suture device for intraocular lens fixation.

PubMed

Smith, Jesse M; Erlanger, Michael; Olson, Jeffrey L

2015-12-01

We describe a surgical technique for scleral fixation of a posterior chamber intraocular lens (PC IOL) using a 24-gauge injectable polypropylene suture delivery system. A 3-piece PC IOL is inserted into the anterior chamber of the eye. Two sclerotomies are made 1.5 mm posterior to the limbus using a microvitreoretinal blade. The 24-gauge injector delivers a preformed suture loop into the eye with the double-armed needles still external to the eye. Each polypropylene IOL haptic is directed through the loop using microforceps. The suture loop is tightened around the haptic, and the attached needles are used to fixate the IOL to the sclera and close the sclerotomies simultaneously. This technique has been used in an ex vivo porcine eye and in an aphakic patient. In the latter, the IOL was quickly fixated to the sclera and maintained a stable position postoperatively. Dr. Olson has a patent pending for the device described in this article. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Using liquid desiccant as a regenerable filter for capturing and deactivating contaminants

DOEpatents

Slayzak, Steven J.; Anderson, Ren S.; Judkoff, Ronald D.; Blake, Daniel M.; Vinzant, Todd B.; Ryan, Joseph P.

2007-12-11

A method, and systems for implementing such method, for purifying and conditioning air of weaponized contaminants. The method includes wetting a filter packing media with a salt-based liquid desiccant, such as water with a high concentration of lithium chloride. Air is passed through the wetted filter packing media and the contaminants in are captured with the liquid desiccant while the liquid desiccant dehumidifies the air. The captured contaminants are then deactivated in the liquid desiccant, which may include heating the liquid desiccant. The liquid desiccant is regenerated by applying heat to the liquid desiccant and then removing moisture. The method includes repeating the wetting with the regenerated liquid desiccant which provides a regenerable filtering process that captures and deactivates contaminants on an ongoing basis while also conditioning the air. The method may include filtration effectiveness enhancement by electrostatic or inertial means.

[Clinical practice guideline on closed tibial plateau fractures in adulthood].

PubMed

Ocegueda-Sosa, Miguel Ángel; Valenzuela-Flores, Adriana Abigail; Aldaco-García, Víctor Daniel; Flores-Aguilar, Sergio; Manilla-Lezama, Nicolás; Pérez-Hernández, Jorge

2013-01-01

Closed tibiae plateau fractures are common injuries in the emergency room. The optimal treatment is not well defined or established. For this reason, there are several surgical management options: open reduction and internal fixation, closed reduction and percutaneous synthesis, external fixation, and even conservative treatment for this kind of fracture. The mechanism of production of this fracture is through large varus or valgus deformation to which is added a factor of axial load. The trauma may be direct or indirect. The degree of displacement, fragmentation and involvement of soft tissues like ligaments, menisci, vascular and nerve structures are determined by the magnitude of the force exerted. Any intra-articular fracture treatment can lead to an erroneous instability, deformity and limitation of motion with subsequent arthritic changes, leading to joint incongruity, limiting activity and significantly altering the quality of life. Open reduction and internal fixation with anatomic restitution is the method used in this type of fracture. However, the results of numerous publications can be questioned due to the inclusion in the same study of fractures treated with very different methods.

Custom-Made Finger Guard to Prevent Wire-Stick Injury to the Operator's Finger while Performing Intermaxillary Fixation.

PubMed

Kumaresan, Ramesh; Ponnusami, Karthikeyan; Karthikeyan, Priyadarshini

2014-12-01

The treatment of maxillofacial fractures involves different methods from bandages and splinting to methods of open reduction and internal fixation and usually requires control of the dental occlusion with the help of intermaxillary fixation (IMF). Different wiring techniques have been used to aid in IMF including placement of custom-made arch bars, eyelet etc. However, these wiring techniques are with a constant danger of trauma to the surgeon's fingers by their sharp ends. Though there exist a variety of commercially available barrier products and customized techniques to prevent wire-stick injury, cost factor, touch sensitivity, and comfort aspect restrain their acquirement and exploit. This technical note describes the construction of a simple and economical finger guard made of soft thermoplastic material that provides an added protection to fingers from wire-stick type injuries, and its flexible nature permits a comfortable finger flexion movement and acceptable touch sensitivity. This is a simple, economical, reusable puncture, and cut-resistance figure guard by which we can avoid wire-stick type injury to the operator's fingers during wiring technique.

Evaluation of different screw fixation techniques and screw diameters in sagittal split ramus osteotomy: finite element analysis method.

PubMed

Sindel, A; Demiralp, S; Colok, G

2014-09-01

Sagittal split ramus osteotomy (SSRO) is used for correction of numerous congenital or acquired deformities in facial region. Several techniques have been developed and used to maintain fixation and stabilisation following SSRO application. In this study, the effects of the insertion formations of the bicortical different sized screws to the stresses generated by forces were studied. Three-dimensional finite elements analysis (FEA) and static linear analysis methods were used to investigate difference which would occur in terms of forces effecting onto the screws and transmitted to bone between different application areas. No significant difference was found between 1·5- and 2-mm screws used in SSRO fixation. Besides, it was found that 'inverted L' application was more successful compared to the others and that was followed by 'L' and 'linear' formations which showed close rates to each other. Few studies have investigated the effect of thickness and application areas of bicortical screws. This study was performed on both advanced and regressed jaws positions. © 2014 John Wiley & Sons Ltd.

Electrochemical Method of Making Porous Particles Using a Constant Current Density

NASA Technical Reports Server (NTRS)

Ferrari, Mauro (Inventor); Cheng, Ming-Cheng (Inventor); Liu, Xuewu (Inventor)

2014-01-01

Provided is a particle that includes a first porous region and a second porous region that differs from the first porous region. Also provided is a particle that has a wet etched porous region and that does have a nucleation layer associated with wet etching. Methods of making porous particles are also provided.

Surface contouring by controlled application of processing fluid using Marangoni effect

DOEpatents

Rushford, Michael C.; Britten, Jerald A.

2003-04-29

An apparatus and method for modifying the surface of an object by contacting said surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on said object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using realtime metrology (e.g. interferometry) to control the placement and dwell time of this wetted zone locally on the surface of said object, thereby removing material from the surface of the object in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

Apparatus For Etching Or Depositing A Desired Profile Onto A Surface

DOEpatents

Rushford, Michael C.; Britten, Jerald A.

2004-05-25

An apparatus and method for modifying the surface of an object by contacting said surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on said object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using real-time metrology (e.g. interferometry) to control the placement and dwell time of this wetted zone locally on the surface of said object, thereby removing material from the surface of the object in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

Positivity-preserving well-balanced discontinuous Galerkin methods for the shallow water flows in open channels

NASA Astrophysics Data System (ADS)

Qian, Shouguo; Li, Gang; Shao, Fengjing; Xing, Yulong

2018-05-01

We construct and study efficient high order discontinuous Galerkin methods for the shallow water flows in open channels with irregular geometry and a non-flat bottom topography in this paper. The proposed methods are well-balanced for the still water steady state solution, and can preserve the non-negativity of wet cross section numerically. The well-balanced property is obtained via a novel source term separation and discretization. A simple positivity-preserving limiter is employed to provide efficient and robust simulations near the wetting and drying fronts. Numerical examples are performed to verify the well-balanced property, the non-negativity of the wet cross section, and good performance for both continuous and discontinuous solutions.

Bi-Pedicle Fixation of Affected Vertebra in Thoracolumbar Burst Fracture.

PubMed

Padalkar, Pravin; Mehta, Varshil

2017-04-01

Burst fractures of the spine account for 14% of all spinal injuries and more than 50% of all thoracolumbar trauma. However, there is ambiguity while choosing the right treatment plan. Short Segment Pedicle screw Fixation (SSPF) has become an increasingly popular method of treatment of thoracolumbar burst fractures, providing the advantage of incorporating fewer motion segments in the fixation. Various biomechanical studies showed that the use of pedicle screws could achieve stable construct within short-segment fixation. To evaluate the efficacy of SSPF using longest possible screws in both pedicles of fractured vertebra. A retrospective chart review of 25 single burst thoracolumbar fracture patients, operated between May 2009 to 2015 in a tertiary care trauma center, was conducted. Preoperative and post-operative plain radiographs were evaluated for kyphotic angulations using the traditional Cobb method. Anterior Vertebral Height (AVH), Posteriors Vertebral Height (PVH) were measured preoperatively and immediate postoperatively. Average percentage loss of AVH and mid-sagittal height were calculated on preoperative and postoperative X-rays on follow up. Fourteen men and 11 women with an average age of 42.92 years comprised the study population. Mean age at the time of operation was 34.5±14.2 years. Mean operation time was 168±72 (minutes). Average hospitalization time was 9±7 (days). Mean blood loss was 515±485 (ml). There were two cases of postoperative infection and implant failure each. A mean of 15.2° of kyphosis correction was attained from pre-operation to post-operation (p<0.0001). Although, there was a 15° average improvement of kyphosis post-fixation, loss of correction over time was nearly 8°, resulting in a 7° mean correction of kyphosis. A mean loss of AVH on postoperative radiograph was 6.12% and maintained 12.4% at the time of review (p<0.001). Similarly, there was 32.8% mid-sagittal height loss at time of injury, which was improved to only 12.6% as compare to initial height loss (p<0.0001). In this study, we propose SSPF using longest possible screws in both pedicle of fractured vertebra. Bi-pedicular fixation gives significant radiological corrections.

[Influencing factors for trauma-induced tibial infection in underground coal mine].

PubMed

Meng, W Z; Guo, Y J; Liu, Z K; Li, Y F; Wang, G Z

2016-07-20

Objective: To investigate the influencing factors for trauma-induced tibial infection in underground coal mine. Methods: A retrospective analysis was performed for the clinical data of 1 090 patients with tibial fracture complicated by bone infection who were injured in underground coal mine and admitted to our hospital from January 1995 to August 2015, including the type of trauma, injured parts, severity, and treatment outcome. The association between risk factors and infection was analyzed. Results: Among the 1 090 patients, 357 had the clinical manifestations of acute and chronic bone infection, 219 had red and swollen legs with heat pain, and 138 experienced skin necrosis, rupture, and discharge of pus. The incidence rates of tibial infection from 1995 to 2001, from 2002 to 2008, and from 2009 to 2015 were 31%, 26.9%, and 20.2%, respectively. The incidence rate of bone infection in the proximal segment of the tibia was significantly higher than that in the middle and distal segments (42.1% vs 18.9%/27.1%, P <0.01) . As for patients with different types of trauma (Gustilo typing) , the patients with type III fracture had a significantly higher incidence rate of bone infection than those with type I/II infection (52.8% vs 21.8%/24.6%, P <0.01) . The incidence rates of bone infection after bone traction, internal fixation with steel plates, fixation with external fixator, and fixation with intramedullary nail were 20.7%, 43.5%, 21.4%, and 26.1%, respectively, suggesting that internal fixation with steel plates had a significantly higher incidence rate of bone infection than other fixation methods ( P <0.01) . The multivariate logistic regression analysis showed that the position of tibial fracture and type of fracture were independent risk factors for bone infection. Conclusion: There is a high incidence rate of trauma-induced tibial infection in workers in underground coal mine. The position of tibial fracture and type of fracture are independent risk factors for bone infection. Vacuum sealing drainage and Ilizarov technique can achieve a satisfactory therapeutic effect.

Biomechanical comparison of supraacetabular external fixation and anterior pelvic bridge plating.

PubMed

Çavuşoğlu, Ali Turgay; Erbay, Fatma Kübra; Özsoy, Mehmet Hakan; Demir, Teyfik

2017-10-01

Unstable pelvic ring injuries are complex and risky injuries due to high morbidity and mortality. Although anterior pelvic external fixator is a suitable method for rapid stabilization of an injured pelvic ring, due to some disadvantages such as high complication rate, nerve damage, and difficulties of patient's mobility and comfort, there has recently been increased searching for alternative methods for stabilization of the pelvic ring. Pubic symphysis zone freely moves in pelvic models. This study aims to evaluate the biomechanical stability of anterior pelvic bridge plating and compare it with supraacetabular external fixators in an untreated unstable pelvic fracture model. Samples were loaded statically with 2-mm/min loading rate in single leg standing position. Maximum load was 2.3 kN. When loading the samples, photographs were taken continuously. Stiffness values were calculated from the load displacement curves. Some reference parameters were described and were measured from unloaded and 2.3-kN-loaded photographs of the test. The mean stiffness values were 491.14 ± 52.22, 478.55 ± 41.44, and 470.25 ± 44.51 N/mm for anterior pelvic bridge plating group, supraacetabular external fixator group, and Control group, respectively. According to the measured parameters from photographs, the mean displacement at the pubic symphysis was 4.7 ± 0.32, 15.8 ± 2.01, and 18.2 ± 0.47 mm for anterior pelvic bridge plating, supraacetabular external fixator, and Control group, respectively. The highest displacement in the pubic symphysis was found in Control group, and minimum displacement was observed in anterior pelvic bridge plating group. When the perpendicular distance between the right and left lower end of ischium was examined, it was observed that displacement was minimum in anterior pelvic bridge plating group compared to other two groups, regarding to the high stability of pubic symphysis. In conclusion, this study revealed superiority of anterior subcutaneous plate fixation with biomechanical results.

The effect of hubs and shortcuts on fixation time in evolutionary graphs

NASA Astrophysics Data System (ADS)

Askari, Marziyeh; Moradi Miraghaei, Zeinab; Aghababaei Samani, Keivan

2017-07-01

How can a new species (like a gene, an idea, or a strategy) take over the whole of a population? This process, which is called fixation, is considerably affected by the structure of the population. There are two key quantities to quantify the fixation process, namely fixation probability and fixation time. Fixation probability has been vastly studied in recent years, but fixation time has not been completely explored, yet. This is because the discovery of a relationship between fixation time and network structure is quite challenging. In this paper we investigate this relationship for a number of well-known complex networks. We show that the existence of a few high-degree nodes (hubs) in the network results in a longer fixation time, while the existence of a few short-cuts decreases the fixation time. Furthermore we investigate the effect of network parameters, such as connection probability, on fixation time. We show that by increasing the density of edges, fixation time decreases for all types of studied networks. Finally, we survey the effect of rewiring probability in a Watts-Strogatz network on fixation time.

Correlation Between Residual Displacement and Osteonecrosis of the Femoral Head Following Cannulated Screw Fixation of Femoral Neck Fractures.

PubMed

Wang, Chen; Xu, Gui-Jun; Han, Zhe; Jiang, Xuan; Zhang, Cheng-Bao; Dong, Qiang; Ma, Jian-Xiong; Ma, Xin-Long

2015-11-01

The aim of the study was to introduce a new method for measuring the residual displacement of the femoral head after internal fixation and explore the relationship between residual displacement and osteonecrosis with femoral head, and to evaluate the risk factors associated with osteonecrosis of the femoral head in patients with femoral neck fractures treated by closed reduction and percutaneous cannulated screw fixation.One hundred and fifty patients who sustained intracapsular femoral neck fractures between January 2011 and April 2013 were enrolled in the study. All were treated with closed reduction and percutaneous cannulated screw internal fixation. The residual displacement of the femoral head after surgery was measured by 3-dimensional reconstruction that evaluated the quality of the reduction. Other data that might affect prognosis were also obtained from outpatient follow-up, telephone calls, or case reviews. Multivariate logistic regression analysis was applied to assess the intrinsic relationship between the risk factors and the osteonecrosis of the femoral head.Osteonecrosis of the femoral head occurred in 27 patients (18%). Significant differences were observed regarding the residual displacement of the femoral head and the preoperative Garden classification. Moreover, we found more or less residual displacement of femoral head in all patients with high quality of reduction based on x-ray by the new technique. There was a close relationship between residual displacement and ONFH.There exists limitation to evaluate the quality of reduction by x-ray. Three-dimensional reconstruction and digital measurement, as a new method, is a more accurate method to assess the quality of reduction. Residual displacement of the femoral head and the preoperative Garden classification were risk factors for osteonecrosis of the femoral head. High-quality reduction was necessary to avoid complications.

Rapid and sensitive sandwich enzyme-linked immunosorbent assay for detection of staphylococcal enterotoxin B in cheese.

PubMed Central

Morissette, C; Goulet, J; Lamoureux, G

1991-01-01

A rapid and sensitive screening sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the detection of staphylococcal enterotoxin B (SEB) in cheese by using a highly avid anti-SEB antibody (Ab) as the capture Ab (CAb) and as the biotinylated Ab conjugate. The glutaraldehyde fixation method for the immobilization of CAb on polystyrene dipsticks was superior to the adsorption fixation and the adsorption-glutaraldehyde fixation methods. The glutaraldehyde fixation method resulted in a higher surface-saturating CAb concentration as evaluated by the peroxidase saturation technique and by the ability of the CAb-coated dipstick to discriminate between positive and negative controls (index of discrimination). Of nine blocking agents used alone or in pairs, lysine-human serum albumin, bovine serum albumin, human serum albumin, and gelatin effectively saturated available sites on the CAb-coated dipsticks without causing interference with the antigen-Ab reactions. The addition of 1% polyethylene glycol to the diluent of the biotinylated anti-SEB Ab conjugate improved the detection of SEB. A concentration of 4% polyethylene glycol allowed a 5-min reaction time for the streptavidin-biotin-horseradish peroxidase conjugate. Cheddar cheese homogenate reduced the sensitivity of the SEB assay; however, the sensitivity was restored when 1.6% (wt/vol) of either a nonionic detergent (Mega-9) or two zwitterionic detergents (Zwittergent 3-10 and 3-12 detergent) was added to the diluent. By using the rapid sandwich ELISA, a minimum of 0.5 to 1.0 ng of SEB per ml was detected within 45 min. The whole procedure for the analysis of the cheddar cheese samples was completed within 1 h.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2039234

Surgical treatment of open pilon fractures.

PubMed

Zeng, Xian-tie; Pang, Gui-gen; Ma, Bao-tong; Mei, Xiao-long; Sun, Xiang; Wang, Jia; Jia, Peng

2011-02-01

To discuss the methods, timing and clinical outcomes of surgical treatment for open pilon fractures. From April 2003 to July 2008, 28 patients with open pilon fractures were treated. All had type C fractures according to the Arbeitsgemeinschaft für osteosynthesefragen-Association for the Study of Internal Fixation (AO/ASIF) classification. Three operative methods were applied, the methods being determined by the types of fracture, soft tissue damage and time interval after injury. Seven cases were treated by debridement and internal fixation with plate; 19 by limited internal fixation combined with external fixation; and 2 by delayed surgery. The clinical outcomes were evaluated by the Burwell-Charnley score. All cases were followed up for from 6 to 48 months (average 24 months). The Burwell-Charnley score of clinical outcomes: anatomic reduction achieved in 12 cases, functional reduction in 15, and unsatisfactory reduction in 1. The healing time was from 2.5 to 11 months (average 4.7 months). Two cases had delayed union. According to the American Orthopaedic Foot and Ankle Society (AOFAS) scale for the ankle joint, there were excellent results in 8 cases, good in 14, fair in 5 and poor in 1. Complications included four cases of skin superficial sloughing, two of superficial infection, one of deep infection, two of delayed fracture union and ten of post-traumatic arthritis. It is important to perform appropriate surgeries for open pilon fracture according to fracture classification, different damage to skin and tissue and time interval after injury. Thorough debridement, proper use of anti-infective medication, appropriate bone grafting, and postoperative ankle function exercise can reduce the occurrence of complications. © 2011 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

Patella Fracture Fixation with Suture and Wire: you Reap what you Sew

PubMed Central

Egol, Kenneth; Howard, Daniel; Monroy, Alexa; Crespo, Alexander; Tejwani, Nirmal; Davidovitch, Roy

2014-01-01

Introduction Operative fixation of displaced inferior pole patella fractures has now become the standard of care. This study aims to quantify clinical, radiographic and functional outcomes, as well as identify complications in a cohort of patients treated with non-absorbable braided suture fixation for inferior pole patellar fractures. These patients were then compared to a control group of patients treated for mid-pole fractures with K-wires or cannulated screws with tension band wiring. Methods In this IRB approved study, we identified a cohort of patients who were diagnosed and treated surgically for a displaced patella fracture. Demographic, injury, and surgical information were recorded. All patients were treated with a standard surgical technique utilizing non-absorbable braided suture woven through the patellar tendon and placed through drill holes to achieve reduction and fracture fixation. All patients were treated with a similar post-operative protocol and followed up at standard intervals. Data were collected concurrently at follow up visits. For purpose of comparison, we identified a control cohort with middle third patella fractures treated with either k-wires or cannulated screws and tension band technique. Patients were followed by the treating surgeon at regular follow-up intervals. Outcomes included self-reported function and knee range of motion compared to the uninjured side. Results Forty-nine patients with 49 patella fractures identified retrospectively were treated over 9 years. This cohort consisted of 31 females (63.3%) and 18 males (36.7%) with an average age of 57.1 years (range 26 - 88 years). Patients had an average BMI of 26.48 (range 19 - 44.08). Thirteen patients with inferior pole fractures underwent suture fixation and 36 patients with mid-pole fractures underwent tension band fixation (K-wire or cannulated screws with tension band). In the suture cohort, one fracture failed open repair (7.6%), which was revised again with sutures and progressed to union. Of the 36 fractures repaired with a tension band fixation, 11 underwent secondary surgery due to hardware pain or fixation failure (30.6%). At one year, no difference was seen in knee range of motion between cohorts. All fractures healed radiographically. Those patients who required reoperation or removal of hardware had significantly diminished range of motion about their injured knee (p > 0.005). Conclusions Patients who sustain inferior pole patella fractures have limited options for fracture fixation. Suture repair is clinically acceptable, yielding similar results to patella fractures repaired with metal implants. Importantly, patients undergoing suture repair appear to have fewer hardware related postoperative complications than those receiving wire fixation for midpole fractures. PMID:25328461