Outcomes of biosynthetic absorbable mesh use in high risk CDC Class I ventral hernia repair: a single surgeon series.

PURPOSE: Biosynthetic absorbable meshes have emerged as suitable alternatives to permanent synthetic and biologic meshes in complex ventral hernia repair in contaminated wounds. Evidence regarding the use of these products in clean wounds is currently scant. This paper presents a large single surgeon series using GORE®BIO-A® (W.L. Gore & Associates, Newark, DE) (Bio-A) tissue reinforcement in high risk patients with predominantly CDC Class I wounds. METHODS: Retrospective review of a prospectively maintained database of consecutive patients who underwent open ventral hernia repair with biosynthetic absorbable mesh was conducted. Ventral Hernia Working Group (VHWG) classification based on patient demographics and Centers for Disease Control (CDC) wound type were collected prospectively. All patients were followed up for a minimum of 12 months post-operatively. RESULTS: 155 patients were included with a mean post-operative follow up of 29 months (range 12-62 months). Mean age was 61.8 years with an average BMI of 33.5 kg/m2. 147 patients (94.9%) were classified as VHWG 2 or 3 based on comorbidities or surgical field contamination. 69% (n = 107) of wounds were designated CDC Class I. Mean hernia size was 119.7cm2 with recurrent defects comprising 32.3% (n = 50). Retrorectus mesh repair was achieved in 84.5% of patients (n  = 131). Post-operative wound events occurred in 19.3%. No mesh was explanted. Hernia recurrence rate was 9.0% with a mean time to recurrence of 14 months. There was no significant difference in recurrence rates between clean and contaminated wounds. CONCLUSION: This study supports the use of Bio-A in high risk ventral hernias, demonstrating a safe and durable repair across all wound classes. Ongoing follow-up continues to monitor for late complications and recurrence.

Is simultaneous panniculectomy an ideal approach to repair a ventral hernia: a general surgeon's experience.

BACKGROUND: The number of Australian patients undergoing ventral hernia repair has seen a significant increase in the last twenty years. With the obesity epidemic, the general surgeon is frequently seeing patients with hernias and significant abdominal aprons and is being asked to address this at the time of the hernia repair. This can be performed utilising a general surgery and plastic surgery team, but there may be some advantages to general surgeon being able incorporate this into their practice. We present our approach to patients undergoing ventral hernia repair and simultaneous panniculectomy (VHR + PAN) by a single general surgeon. METHODS: Data were analysed from a single surgeon's experience performing VHR + PAN at the same operation. Data were collected prospectively from 2009 to 2020. 146 cases of patients undergoing VHR + PAN were identified and included in this study. RESULTS: The mean age of patients undergoing VHR + PAN was 58 years. The mean BMI was 35, with 59% of patients losing weight loss prior to surgery. 66% of patients had a hernia repair with biosynthetic mesh and 91% of patients had retro-rectus or pre-peritoneal mesh approach to the repair. 42% of patients had a post-operative complication with 80.6% of these being related to surgical-site occurrences. Other complications included gastrointestinal (14%), respiratory (13%) and venous thromboembolism, such as a deep vein thrombus or pulmonary embolism (6%). There were 2 deaths in the series (1.3%). The hernia recurrence rate was 6%. CONCLUSION: Simultaneous PAN is possible in patients with an abdominal apron who are undergoing VHR, with an acceptable risk of SSOs and other complications. This technique provides excellent exposure and with appropriate training is well within the remit of the general surgeon. This may save further operative management in the future and can offer patients improved self-esteem, mobility, and independence. Patient optimisation is key, paying careful attention to pre-operative weight loss, diabetic control, smoking cessation and respiratory function. VHR + PAN is an important technique that should be in the repertoire of all abdominal wall reconstruction units.

The tension between efficiency and effectiveness: a study of dietetic practice in primary care.

BACKGROUND: Primary healthcare dietitians have a vital role to play in the prevention and management of chronic disease. Working in primary care requires efficient and effective management of practice to ensure client and practitioner needs are met. The present study aimed to explore the way in which primary care dietitians in Australia view the constructs of efficiency and effectiveness within the context of their practice. METHODS: The study used an exploratory qualitative design within a pragmatist framework. Individual semi-structured telephone interviews were conducted with Australian primary care dietitians. All interviews were audio-recorded, transcribed verbatim and analysed using an inductive thematic approach. RESULTS: Twenty dietitians (17 females) working as private practitioners in primary care from three Australian states participated in the present study. Three themes emerged from the data. The first theme revealed that seeking efficiency and especially effectiveness were important to primary care dietitians and that there was a tension between the two. The second theme identified that efficiency and effectiveness are influenced by personal and structural factors. The final theme explored how dietitians are actively seeking ways to be more efficient and effective, including supportive networks, as well as the utilisation of technology. CONCLUSIONS: Achieving a balance between efficiency and effectiveness in primary care dietetics is challenging to practitioners, who may require further training and support to enhance productivity, time management and resource utilisation. Structured issues exist for the workface. Further studies are required to quantify these findings and to explore whether it is possible to optimise efficiency and effectiveness and achieve sustainability of the dietetic workforce in primary care.

Evaluation of oncogenic cysteinyl leukotriene receptor 2 as a therapeutic target for uveal melanoma.

Uveal melanoma is a rare, but deadly, form of eye cancer that arises from melanocytes within the uveal tract. Although advances have emerged in treatment of the primary tumour, patients are still faced with vision loss, eye enucleation and lethal metastatic spread of the disease. Approximately 50% of uveal melanoma patients develop metastases, which occur most frequently in the liver. Metastatic patients encounter an extremely poor prognosis; as few as 8% survive beyond 2 years. Understanding of the genetic underpinnings of this fatal disease evolved in recent years with the identification of new oncogenic mutations that drive uveal melanoma pathogenesis. Despite this progress, the lack of successful therapies or a proven standard-of-care for uveal melanoma highlights the need for new targeted therapies. This review focuses on the recently identified CYSLTR2 oncogenic mutation in uveal melanoma. Here, we evaluate the current status of uveal melanoma and investigate how to better understand the role of this CYSLTR2 mutation in the disease and implications for patients harbouring this mutation.

Intervención de ejercicios de habilidad motora manual en el dolor y función en sujetos adultos con artritis reumatoide: serie de casos / Intervention of manual motor skill exercises on pain and function in ality adults subjets with rheumatoid arthritis: case series

Introducción: La artritis reumatoide tiene un significativo impacto negativo en la capacidad para realizar labores diarias, incluyendo el trabajo, las tareas del hogar y la calidad de vida. Los hallazgos experimentales y clínicos sugieren que el reentrenamiento de la habilidad motora puede proporcionar mejoras en pacientes con dolor crónico de muñeca y mano. Objetivo: Describir los cambios en la función manual, en la fuerza de puño y en el dolor, a la sexta semana y al tercer mes tras la aplicación de ejercicios enfocados en la habilidad motora manual en adultos con artritis reumatoide. Método: Estudio de diseño no experimental, descriptivo serie de casos, muestra 17 participantes con diagnóstico de artritis reumatoide. Los pacientes realizaron un programa de ejercicios enfocados en la habilidad motora manual durante 6 semanas. Se midieron las variables de función, dolor, fuerza de puño y pinza, a la sexta semana y al tercer mes. Resultados: No existe diferencia significativa en la intensidad del dolor, función y fuerza de puño, postintervención p > 0,05. Existe diferencia significativa a la sexta semana en la fuerza de pinza p = 0,002. Durante el seguimiento al tercer mes solo hubo diferencia significativa en la fuerza de puño p = 0,01. Conclusión: La aplicación de un programa de ejercicios enfocados en la habilidad motora manual generó cambios a nivel de la fuerza de puño y pinza. Con respecto a la funcionalidad e intensidad del dolor no se apreciaron diferencias significativas (AU)

Introduction: Rheumatoid arthritis has a significant negative impact on the ability to perform daily tasks, including work, household chores and quality of life. Experimental and clinical findings suggest that retraining of motor skills may provide improvements in patients with chronic pain the wrist and hand. Objective: To describe the changes in the manual function, the grip strength and pain, to the sixth week and to the third month after the application of exercises focused on manual motor skills, in adults with rheumatoid arthritis. Method: Non-experimental design study, descriptive case series, sample 17 participants with diagnosis of rheumatoid arthritis. The patients performed a program of exercises focused on manual motor skill for 6 weeks. Were measured at the variables of function, the grip strength , digtal clamp and pain, the sixth week and at the third month. Results: There was no significant difference in pain intensity, function and the grip strength, post intervention p > 0,05. There was significant difference at the sixth week in the digital clamp p = 0.002. During follow-up at the third month, there was only significant difference in the grip strength p = 0.01. Conclusion: The application of a program of exercises focused on the manual motor skill, generated changes a level of the grip strength and clamp. Regarding the functionality and intensity of pain, there were no significant differences (AU)

Software for improved field surveys of nesting marine turtles.

Field data are still recorded on paper in many worldwide beach surveys of nesting marine turtles. The data must be subsequently transferred into an electronic database, and this can introduce errors in the dataset. To minimize such errors, the "Turtles" software was developed and piloted to record field data by one software user accompanying one Tortuguero in Akumal beaches, Quintana Roo, Mexico, from June 1st to July 31st during the night patrols. Comparisons were made between exported data from the software with the paper forms entered into a database (henceforth traditional). Preliminary assessment indicated that the software user tended to record a greater amount of metrics (i.e., an average of 18.3 fields ± 5.4 sd vs. 8.6 fields ± 2.1 sd recorded by the traditional method). The traditional method introduce three types of "errors" into a dataset: missing values in relevant fields (40.1%), different answers for the same value (9.8%), and inconsistent data (0.9%). Only 5.8% of these (missing values) were found with the software methodology. Although only tested by a single user, the software may suggest increased efficacy and warrants further examination to accurately assess the merit of replacing traditional methods of data recording for beach monitoring programmes.

Utility of a multiple serum biomarker test to monitor remission status and relapse in dogs with lymphoma undergoing treatment with chemotherapy.

A blinded retrospective study was conducted to investigate remission and recurrence of lymphoma in dogs receiving chemotherapy. The objective was to compare clinicians' assessment using palpation and cytology to the results of serum biochemical tests for haptoglobin (Hapt) and C-reactive protein (C-RP). These biochemical test results were combined using a diagnostic algorithm developed using data from 344 individual dogs. This multivariate approach, termed the canine lymphoma blood test (cLBT), was used to follow 57 dogs during and after treatment. cLBT of remission and recurrence compared well with clinicians' assessment and differentiated dogs in remission and those with recurring disease before appearance of lymphadenopathy (P < 0.001). The cLBT demonstrated prognostic potential based on pre-treatment values on dogs with shorter survival times and on those achieving the lowest cLBT score during treatment that showed longer survival times. The test, therefore, demonstrates potential to assist in monitoring treatment of canine lymphoma.

Computational diagnosis and risk evaluation for canine lymphoma.

The canine lymphoma blood test detects the levels of two biomarkers, the acute phase proteins (C-Reactive Protein and Haptoglobin). This test can be used for diagnostics, for screening, and for remission monitoring as well. We analyze clinical data, test various machine learning methods and select the best approach to these oblems. Three families of methods, decision trees, kNN (including advanced and adaptive kNN) and probability density evaluation with radial basis functions, are used for classification and risk estimation. Several pre-processing approaches were implemented and compared. The best of them are used to create the diagnostic system. For the differential diagnosis the best solution gives the sensitivity and specificity of 83.5% and 77%, respectively (using three input features, CRP, Haptoglobin and standard clinical symptom). For the screening task, the decision tree method provides the best result, with sensitivity and specificity of 81.4% and >99%, respectively (using the same input features). If the clinical symptoms (Lymphadenopathy) are considered as unknown then a decision tree with CRP and Hapt only provides sensitivity 69% and specificity 83.5%. The lymphoma risk evaluation problem is formulated and solved. The best models are selected as the system for computational lymphoma diagnosis and evaluation of the risk of lymphoma as well. These methods are implemented into a special web-accessed software and are applied to the problem of monitoring dogs with lymphoma after treatment. It detects recurrence of lymphoma up to two months prior to the appearance of clinical signs. The risk map visualization provides a friendly tool for exploratory data analysis.

Proteomic identification and profiling of canine lymphoma patients.

This study employed proteomic and bioinformatic approaches to identify serum biomarkers in canine lymphoma patients. Chilled serum samples derived from non-lymphoma (n = 92) and lymphoma (n = 87) patients were shipped from first opinion veterinary practices, subjected to ion exchange chromatography and analysed by surface-enhanced laser desorption ionization mass spectrometry. Nineteen serum protein peaks were identified between the two groups as being significantly different (P < 0.05) based upon their normalized ion intensities. Two biomarkers were identified that were capable of differentiating lymphoma and non-lymphoma patients. Analysis of the test data provided a positive predictive value (PPV) of 82%. A clinical follow-up study was carried out on 96 canine patients suspected of having lymphoma. Evaluation of this data gave a specificity value of 91%, sensitivity of 75%, PPV of 80% and negative predictive value of 88%. In conclusion, the expression pattern of two serum biomarkers has enabled serum samples to be classified into either lymphoma or non-lymphoma categories.

Iatrogenic bile duct injury: the scourge of laparoscopic cholecystectomy.

BACKGROUND: Laparoscopic cholecystectomy (LC) has become the first-line surgical treatment of calculous gall-bladder disease and the benefits over open cholecystectomy are well known. In the early years of LC, the higher rate of bile duct injuries compared with open cholecystectomy was believed to be due to the 'learning curve' and would dissipate with increased experience. The purpose of the present paper was to review a tertiary referral unit's experience of bile duct injuries induced by LC. METHODS: A retrospective analysis was performed on all patients referred for management of an iatrogenic bile duct injury from 1981 to 2000. For injuries sustained at LC, details of time between LC and recognition of the injury, time from injury to definitive repair, type of injury, use of intraoperative cholangiography (IOC), definitive repair and postoperative outcome were recorded. The type of injury sustained at open cholecystectomy was similarly classified to allow the severity of injury to be compared. RESULTS: There were 131 patients referred for management of an iatrogenic bile duct injury that occurred at open cholecystectomy (n = 62), liver resection (n = 5) and at LC (n = 64). Only 39% of bile duct injuries were recognized at the time of LC. Following conversion to open operation, half the subsequent procedures were considered inappropriate. When the injury was not recognized during LC, 70% of patients developed bile leak/peritonitis, almost half of whom were referred, whereas the rest underwent a variety of operative procedures by the referring surgeon. The remainder developed jaundice or abnormal liver function tests and cholangitis. An IOC was performed in 43% of cases, but failed to identify an injury in two-thirds of patients. The bile duct injuries that occurred at LC were of greater severity than with open cholecystectomy. Following definitive repair, there was one death (1.6%). Ninety-two per cent of patients had an uncomplicated recovery and there was one late stricture requiring surgical revision. CONCLUSIONS: The early prediction that the rate of injury during LC would decline substantially with increased experience has not been fulfilled. Bile duct injury that occurs at LC is of greater severity than with open cholecystectomy. Bile duct injury is recognized during LC in less than half the cases. Evidence is accruing that the use of cholangiography reduces the risk and severity of injury and, when correctly interpreted, increases the chance of recognition of bile duct injury during the procedure. Prevention is the key but, should an injury occur, referral to a specialist in biliary reconstructive surgery is indicated.

A humanized anti-human CD154 monoclonal antibody blocks CD154-CD40 mediated human B cell activation.

Humanized anti-CD154 antibody, IDEC-131, had a slightly, but reproducibly, better binding affinity for CD154 (Kd = 5.6 nM), compared to the parent antibody 24-31 (Kd = 8.5 nM). Otherwise it was indistinguishable from the murine parent antibody in its ability to bind to CD154, block CD154 binding to CD40 and inhibit T cell-dependent B cell differentiation. The latter activity was independent of FcR binding as the Fab'1 fragment of IDEC-131 had an equivalent biological activity to that of the whole antibody. IDEC-131 blocked soluble CD154 from inducing proliferation of purified B cells, and blocked T cell dependent anti-tetanus toxoid specific antibody production by human B cells in vitro. IDEC-131, gamma1, kappa, had strong Fc gammaRI, Fc gammaRII and C1q binding, but was unable to induce complement dependent (CDC) or antibody dependent cell-cytotoxicity (ADCC) of activated peripheral blood T cells, which express relatively low levels of CD154. IDEC-131 antibody inhibited both primary and secondary antibody responses to ovalbumin in cynomolgus monkeys at a dose of 5 mg/kg. In non-immunized animals, treatment with IDEC-131 at 50 mg/kg weekly for 13 weeks induced no change in any of the measured lymphocyte subsets, including B cells, CD4+ and CD8+ T cells. Similarly, a safety study in chimpanzees showed no discernible safety related issues at 20 mg/kg, including B and T cell subsets. These results show that the humanized anti-CD154 antibody, IDEC-131, has retained the affinity and functional activity of its murine parent antibody, is unlikely to deplete CD154 positive lymphocytes in humans, and is safe and effective in blocking antibody production in monkeys. Based on its safety and efficacy profile, IDEC-131 is being developed for therapy of systemic lupus erythematosus.

Epidemic typhus meningitis in the southwestern United States.

A patient residing in New Mexico had murine typhus diagnosed. A novel molecular assay was performed at the Centers for Disease Control and Prevention, and Rickettsia prowazekii, the agent of epidemic typhus, was found, rather than R. typhi. To our knowledge, this is the first reported case of epidemic typhus confirmed by means of polymerase chain reaction--based testing of cerebrospinal fluid, and it introduces a novel assay for the molecular diagnosis of both epidemic and murine typhus.

Cytotoxicity tests for high-throughput drug discovery.

Despite theoretical obstacles associated with performing cell-based assays in high-density formats (microplates with at least 384 wells), it is becoming clear that the pharmaceutical industry is now routinely running cell-based tests in these formats. This work is revealing the weakness of established cytotoxicity end points, specifically in relation to sensitivity and reproducibility. New assay kits based on bioluminescent detection of ATP and ADP are now providing the answer to these problems.

Survival of Ehrlichia chaffeensis in refrigerated, ADSOL-treated RBCs.

BACKGROUND: The purpose of this study was to investigate the persistence of viable Ehrlichia chaffeensis in ADSOL-treated RBCs stored at 4 to 6 degrees C. STUDY DESIGN AND METHODS: The continuous monocytic cell lines THP-1 and DH82 were infected with E. chaffeensis (St. Vincent isolate). Packed RBC units were inoculated in separate experiments with E. chaffeensis-infected cells as final concentrations of 8.02 x 10(4) (DH82) and 1.43 x 10(4) (THP-1) infected cells per mL. Aliquots were stored at 4 to 6 degrees C for 1 to 42 days. At selected intervals, nucleated cells from the RBC aliquots were obtained by using a ficoll-isopaque separation procedure. Uninfected DH82 cell cultures were inoculated with the harvested nucleated cells or supernatant. The cell cultures were evaluated for infection by weekly examination of Wright's (Diff-Quik) stained cytocentrifuged slides. PCR amplification was also used to test the harvested nucleated cells or supernatant for the presence of E. chaffeensis DNA. RESULTS: In both types of infected cell lines, E. chaffeensis was reisolated in DH82 cells for as long as 11 days from the cellular fraction and for up to 5 days from the supernatant fraction. PCR results were positive throughout the 42-day testing period. CONCLUSION: Cell-associated E. chaffeensis remains viable in ADSOL-treated RBCs stored at 4 to 6 degrees C for at least 11 days. These data suggest that transfusion-acquired infection is possible. Successful reisolation was achieved from the supernatant fraction, which suggests that RBC products treated with a WBC-reduction procedure may still present a risk for transfusion transmission. No correlation between PCR positivity and viability of bacteria was noted.

Measurement of the ADP:ATP ratio in human leukaemic cell lines can be used as an indicator of cell viability, necrosis and apoptosis.

In this study the relative levels of ADP and ATP have been measured in cells undergoing apoptosis. Using HL60, CEM7, Jurkat and U937 cell lines and cytotoxic agents known to induce apoptosis, there was a significant correlation (P<0.01 for all models) between the ADP:ATP ratio and the degree of apoptosis measured by TUNEL and estimation of the sub G(0) fraction by propidium iodide staining and flow cytometry. The ratio measured in viable proliferating cells was found to be less than 0.11 compared with ratios between 0.11 and 1.0 seen in cells undergoing apoptosis. The higher the percentage of hypodiploidy the greater the ratio. Necrosis induced by heat shock resulted in ADP:ATP ratios in excess of 15.0. When primary cultures of AML blast cells were used, there was again a significant correlation between the ADP:ATP ratio and the degree of hypodiploidy. Recent evidence suggests that apoptosis is accompanied by opening of the mitochondrial permeability pores, leading to disruption of the mitochondrial transmembrane potential (DeltaPsi(m)). This results in caspase activation due to the release of cytochrome c and apoptogenic factors into the cytosol. In five experiments using CEM7 and dexamethasone the mitochondrial transmembrane potential was assessed using the fluorescent cyanine dye JC-1 and flow cytometry. Functioning mitochondria concentrate the JC-1 to produce red fluorescence. Loss of mitochondrial transmembrane potential results in green fluorescence only. The percentage of cells exhibiting red fluorescence correlated positively with the ATP values and negatively with the ADP:ATP ratio.

Absenteeism and the impact of a 38-hour week, rostered day off option.

We undertook a comparative analysis of nurses working in two consecutive years: one in a 40-hour standard working week and the other in a 38-hour week with a rostered day off per month, in order to determine whether there was any effect on absenteeism. We found that total absenteeism between the two years fell significantly from 4.58% to 4.36% (chi 2 = 5.09, P = 0.024). Sick leave decreased but not to a significant degree. We conclude that the change to the 38-hour week and 19-day month (rostered day off) arrangements led to a significant reduction in overall absenteeism but not in sick leave. However, the cost in implementing a 19-day month is far in excess of any savings made through absenteeism reductions.

An investigation into the possibility of transmission of tick-borne pathogens via blood transfusion. Transfusion-Associated Tick-Borne Illness Task Force.

BACKGROUND: Tick-borne illnesses were diagnosed in a group of National Guard members, including some who had donated blood a few days before the onset of symptoms. A voluntary recall of those blood components was issued and a multistate investigation was conducted to determine if transfusion-transmitted illness had occurred. STUDY DESIGN AND METHODS: Donors and recipients were asked to complete questionnaires regarding symptoms and risk factors for infection and to provide blood samples for laboratory analysis. RESULTS: Among National Guard personnel who donated blood, 12 individuals were found to have a confirmed or probable case of Rocky Mountain spotted fever or ehrlichiosis. A total of 320 units (platelets or packed red cells) from 377 donors were transfused into 129 recipients. Although 10 recipients received units from National Guard personnel with confirmed or probable infection, none became ill. CONCLUSION: Transfusion-transmitted illness did not occur. Despite the awareness of the risk for tick-borne diseases and the use of tick-preventive measures, many National Guard personnel reported exposure to ticks. In addition to augmenting current tick-preventive measures, scheduling blood drives before rather than after field exercises could further reduce the potential for transmission of tick-borne pathogens.

Operative reconstruction after transverse rupture of the tendons of both peroneus longus and brevis. Surgical reconstruction by transfer of the flexor digitorum longus tendon.

Rupture of the tendons of both peroneus longus and peroneus brevis results in considerable disability. We have performed transfer of flexor digitorum longus (FDL) to peroneus brevis in two patients with lateral instability of the hindfoot due to chronic transverse tears of both tendons for which end-to-end repair was not possible. Both patients had excellent function when reviewed after eight and six years, respectively, with no symptoms. CT showed a normal appearance of the FDL in both patients, but the peroneal muscles looked abnormal. Transfer of the FDL provides a reliable solution to lateral instability of the hindfoot resulting from loss of function of both peronei.

Nested PCR assay for detection of granulocytic ehrlichiae.

A sensitive and specific nested PCR assay was developed for the detection of granulocytic ehrlichiae. The assay amplifies the 16S rRNA gene and was used to examine acute-phase EDTA-blood and serum samples obtained from seven humans with clinical presentations compatible with human granulocytic ehrlichiosis. Five of the seven suspected cases were positive by the PCR assay using DNA extracted from whole blood as the template, compared with a serologic assay that identified only one positive sample. The PCR assay using DNA extracted from the corresponding serum samples as the template identified three positive samples. The sensitivity of the assay on human samples was examined, and the limit of detection was shown to be fewer than 2 copies of the 16S rRNA gene. The application of the assay to nonhuman samples demonstrated products amplified from template DNA extracted from Ixodes scapularis ticks collected in Rhode Island and from EDTA-blood specimens obtained from white-tailed deer in Maryland. All PCR products were sequenced and identified as specific to granulocytic ehrlichiae. A putative variant granulocytic ehrlichia 16S rRNA gene sequence was detected among products amplified from both the ticks and the deer blood specimens.

Comparative analysis of below-knee prosthetic socket liner materials.

Four materials used in lining prosthetic sockets were compared for their potential usefulness in below-knee applications. Tests carried out included determinations of resistance to compression, resistance to flexural abrasion and coefficients (static and dynamic) of friction. These tests were designed, respectively, to assess changes occurring during end-use brought about by extensive application of compressive or shear force, and to predict the ability to retain contact with the body and socket. Of the four materials in the study (Bock-Lite, Pedilin, polyurethane and silicone), Bock-Lite and silicone had high compression resistance, Bock-Lite had good resistance to flexural abrasion, and polyurethane and silicone had high coefficients of frictional resistance. Thus, Bock-Lite will be the most durable of the four materials but, since it had the lowest frictional coefficient, it may slip in use. Conversely, silicone and polyurethane, which will be retained in position more easily, are easily torn or compressed, so are likely to need replacement more frequently.