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BACKGROUND: In patients with nerve tissue defects, the use of autologous nerve grafts is the standard method of treatment. Alternatives to autologous, nerve grafts have attracted the attention of reconstructive surgeons. In this study, the results of nerve repairs using acellular dermal matrix (ADM) in an experimental rat sciatic nerve defect model are presented. METHODS: Thirty-six Sprague-Dawley rats were randomized into 5 groups: Group 1: control group, Group 2: negative control group (n = 6), Group 3: autologous nerve graft group (n = 10), Group 4: donor site entubulated with ADM group (n = 10); and Group 5: nerve graft entubulated with ADM group (n = 10). The animals in each group were evaluated for electrophysiologic functions, gastrocnemius muscle weight and histomorphology on the 3rd and 6th month. RESULTS: The compound muscle action potential was observed to be distinctly lower in Groups 3, 4 and 5 in comparison to the control group. In Group 4, the gastrocnemius ratio (GCR) values on the 6th month were statistically significantly lower than the GCR values in Group 3 and Group 5, The histological scores and myelinated axonal counts in Group 5 were statistically significantly higher than the values in Group 3 and Group 4. CONCLUSION: The results of this study showed that wrapping ADM around nerve grafts resulted in better outcomes with respect to nerve healing.

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Background: Current methods used to measure the muscle strength required to achieve plantar flexion may yield highly variable results depending on the perception of the physician conducting the examination because these tests involve subjective and qualitative evaluation. Objective: To describe and evaluate the efficacy of a novel examination technique that can quantitatively measure plantar flexion in L5-S1 disc herniation. Materials and Methods: A total of 32 patients (average age: 49.4 years, range: 23-78) with L5-S1 disc herniations were included. The patient to be tested stood next to a table on which they could lean with their hands. The leg closer to the table was fully flexed at the knee, and the other foot was brought to maximum plantar flexion on the toes. At this point, a stopwatch was started to measure the time that passed until the muscles fatigued and the heel fell. The differences between the right and left plantar flexion times were noted. In addition, three different physicians graded muscle strength by using the classical "The Medical Research Council of the United Kingdom" method. Results: The time until fatigue in right and left plantar flexion was measured using the proposed method, and each test underwent a video recording. The Yilmaz-Ilbay plantar flexion test yielded the correct classification for all cases. Conclusion: We suggest that the proposed method "Yilmaz-Ilbay plantar flexion test" can serve as a useful, practical, and effective test to detect quantitative evaluation of plantar flexion in L5-S1 herniation.

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AIM: Epineural adhesion after peripheral nerve surgery is common. The purpose of this study was to evaluate the macroscopic and histopathologic effects of topical mitomycin C and daunorubicin on epineural scar formation. MATERIAL AND METHODS: In this study, we used 15 rats (30 nerves). Two test groups and one control group were created. Sciatic nerve exposure was created bilaterally in each group (30 nerve examinations in total). In experimental group 1, cotton pads that had absorbed mitomycin C (0.5 mg/ml) were placed onto the nerves for 5 minutes while in experimental group 2, cotton pads that had absorbed daunorubicin (0.2 mg/ml) were placed onto the nerves for 5 minutes and cotton pads that had absorbed saline were applied to the control group. Eight weeks after the first surgery, surgical dissection was performed for the evaluation of neurolysis sites. Epineural adhesions were classified utilizing a numerical grading layout. RESULTS: We did not find any adverse effect with topically applied mitomycin C and daunorubicin. Within the 3 groups, no significant difference was seen in skin and fascia-muscle cavity closure (p > 0.05). Macroscopically, mitomycin C and daunorubicin decreased the adhesion of sciatic nerve to adjacent structures. There was intensive epineural scar formation in the control group. Scar tissue thickness and fibroblast/fibrocyte cell number were less in the two test groups compared with the control group (p < 0.001). There was no statistical difference between the two test groups. CONCLUSION: Epineural scar formation after peripheral nerve surgery may be reduced by using topical application of mitomycin C and daunorubicin.

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STUDY DESIGN: This was a retrospective study of patients who had developed a dural tear after thoracic and lumbar spine surgery that was not recognized during the surgery, and was treated either by lumbar drainage or over-sewing of the wounds. PURPOSE: To revisit the treatment strategies in postoperative dural leaks and present our experience with over-sewing of the wound and lumbar drainage. OVERVIEW OF LITERATURE: Unintended durotomy is a frequent complication of spinal surgery. Management of subsequent cerebrospinal fluid leakage remains controversial. There is no distinct treatment guideline according to the etiology in the current literature. METHODS: The records of 368 consecutive patients who underwent thoracic and/or lumbar spine surgery from 2006 throug h 2010 were retrospectively reviewed. Seven cerebrospinal fluid fistulas and five pseudomeningoceles were noted in 12 (3.2%) procedures. Cerebrospinal fluid diversion by lumbar drainage in five pseudomeningoceles and over-sewing of wounds in seven cerebrospinal fluid fistulas employed in 12 patients. Clinical grading was evaluated by Wang. RESULTS: Of the 12 patients who had a dural tear, 5 were managed successfully with lumbar drainage, and 7 with oversewing of the wound. The clinical outcomes were excellent in 9 patients, good in 2, and poor in 1. Complications such as neurological deficits, or superficial or deep wound infections did not develop. A recurrence of the fistula or pseudomeningocele after the treatment was not seen in any of our patients. CONCLUSIONS: Pseudomeningoceles respond well to lumbar drainage, whereas over-sewing of the wound is an alternative treatment option in cerebrospinal fluid fistulas without neurological compromise.

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This paper presents the use of recurrent neural networks (RNNs) for diagnosis of carpal tunnel syndrome (CTS) (normal, right CTS, left CTS, bilateral CTS). The RNN is trained with the Levenberg-Marquardt algorithm. The RNN is trained on the features of CTS (right median motor latency, left median motor latency, right median sensory latency, left median sensory latency). The multilayer perceptron neural network (MLPNN) is also implemented for comparison the performance of the classifiers on the same diagnosis problem. The total classification accuracy of the RNN is significantly high (94.80%). The obtained results confirmed the validity of the RNNs to help in clinical decision-making.

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This paper illustrates the use of mixture of experts (ME) network structure to guide model selection for diagnosis of two subtypes of adult hydrocephalus (normal-pressure hydrocephalus-NPH and aqueductal stenosis-AS). The ME is a modular neural network architecture for supervised learning. Expectation-Maximization (EM) algorithm was used for training the ME so that the learning process is decoupled in a manner that fits well with the modular structure. To improve classification accuracy, the outputs of expert networks were combined by a gating network simultaneously trained in order to stochastically select the expert that is performing the best at solving the problem. The classifiers were trained on the defining features of NPH and AS (velocity and flux). Three types of records (normal, NPH and AS) were classified with the accuracy of 95.83% by the ME network structure. The ME network structure achieved accuracy rates which were higher than that of the stand-alone neural network models.

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OBJECT: Epineural fibrosis may complicate peripheral nerve surgeries and currently is considered as one of the main factors responsible for failed surgeries. The authors investigated the postoperative antiscarring effects of topically applied doxorubicin (DXR) on rat sciatic nerves. METHODS: The sciatic nerves were dissected from the surrounding tissue and exposed bilaterally in 20 Wistar albino adult male rats. Abrasion trauma was produced on the exposed surface of the biceps femoris muscle in the vicinity of the sciatic nerves and their main branches in all animals. In the DXR Group, cottonoid pads soaked with DXR (0.5 mg/ml) were placed around the nerves for 5 minutes, whereas cotton pads soaked with saline (0.9% NaCl) were applied to nerves of animals in the Control Group for the same duration. Twelve weeks after the procedure, all of the rats were killed and the sciatic nerves were examined. Epineural adhesions were evaluated histopathologically and ultrastructurally. Additionally, quantitative histological parameters, the scar tissue formation index and the scar density, were calculated in histological evaluation. RESULTS: Gross postsurgical evaluation as well as histopathological and electron microscopic examination of involved nerve segments showed significantly less epineurial adhesions in the DXR Group than in the Control Group. Quantitative analysis of the epineurium revealed a statistically significant reduction in the density and amount of epineural scarring in specimens from the DXR Group than in those from the Control Group. CONCLUSIONS: The results of gross postsurgical anatomical evaluation and histopathological and ultrastructural studies suggested that topical application of DXR effectively reduced epineural scar formation on rat sciatic nerves. These promising findings merit further experimental and clinical studies to determine the efficacy and safe applicability of DXR in human subjects.

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The presence of myelomeningocele at multiple levels along the spinal column is extremely rare. There are only a few cases of double myelomeningocele reported in the literature. We report the case of a newborn male who had two myelomeningoceles with one at the cervical level and the other at the lumbar level. This unusual case report as well as a review of the literature is presented.

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The role of topically applied mitomycin C in preventing postoperative perineural fibrosis was examined by gross anatomical dissection and histological analysis in rats. The sciatic nerve was exposed bilaterally in 24 Wistar adult male rats, and an abrasion injury was produced on the exposed surface of the biceps femoris muscle in all animals. In the experimental group, cotton pads soaked with mitomycin C (0.5 mg/ml) were placed around the nerves for 5 min, whereas cotton pads soaked with saline were applied to the control group. Four weeks after surgery, the neurolysis sites were evaluated by blinded surgical dissection. Perineural adhesions were graded using a numerical grading scheme. The scar tissue formation index was also calculated, and a grading was made according to the number of fibroblasts/fibrocytes counted around the epineurium in histological evaluation. Mitomycin C-treated nerves showed significantly less perineural adhesions than controls. Quantification of the dense connective tissue surrounding the nerves revealed a statistically significant reduction around nerves treated with mitomycin C, and the number of fibroblast/fibrocytes was also significantly reduced. Application of topical mitomycin C might be effective in preventing epineural scar formation after neurolysis of peripheral nerves.

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Primitive neuroepithelial tumors are the least common among supratentorial tumors in children. They pose great diagnostic difficulty, preoperatively as well as pathologically. Being quite rare, cerebral neuroblastomas are accepted as a distinct pathological entity, which differs from other neuroectodermal tumors, although clinically, radiologically, and morphologically at operation they are indistinguishable. Also differentiation between primary cerebral neuroblastoma and the other primitive neuroectodermal tumors may be difficult on light microscopy and be misleading. A 9-year-old girl with primary cerebral neuroblastoma who was initially misdiagnosed is reported. The other cases from the literature are reviewed and the nature of this rare tumor and its differential diagnosis is discussed.

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