Thermoelastic Stresses Alleviation for Two-Dimensional Functionally Graded Cylinders Under Asymmetric Loading

Open Access via the Taylor and Francis Agreement Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPublisher PD

Impact of occult hepatitis B virus infection on antiviral therapy in chronic hepatitis C patients

Background: Occult HBV infection (OBI) can be defined by the presence of HBV-DNA in the serum of patients who are negative for HBsAg. The presence of OBI has been associated with a poor therapeutic response to alpha IFN in many, but not in all studies.Objective: The aim of our study was to assess the prevalence of OBI in the serum of Egyptian patients with CHC, and to evaluate its impact on the response to treatment with a combination of Peg-IFNa and RBV.Materials and methods: Fifty chronic HCV infected patients who were treated with Peg-IFNa once a week in combination with RBV for 48 weeks were included in this study. Patients were divided into two groups, group I which included 25 patients who achieved SVR and group II that included 25 patients who failed to achieve SVR (Non-SVR). Both patient groups were subjected to detailed questionnaire, clinical examination, routine laboratory investigations and virological studies.Results: No statistical significant difference was found in sex distribution regarding SVR and Non-SVR. The frequency of patients with low viral load has a statistically significant association.KEYWORDS: Chronic hepatitis C; Occult HBV infection; Sustained virological respons

Low cost detection of hepatitis C virus RNA in HCV infected patients by SYBR Green I real-time PCR

The prevalence of hepatitis C virus (HCV) is highest in Egypt compared to other countries. Nucleic acid amplification test (NAT) allows detection of HCV early during the course of infection. Unfortunately, NAT is more expensive than ELISA, thus its routine use as a screening tool for blood products or in clinical practice is quite limited. The aim of this study was to compare two common RT-PCR methods, TaqMan probe technique and SYBR Green method in quantitative detection of HCV RNA for diagnosis and follow up of HCV patients. Among the recruited 220 HCV patients, 154 (70%) were HCV-RNA positive by both the techniques, while 24 (10.9%) were negative by both techniques. On the other hand, 40 (18.2%) cases were HCV RNA positive only by SYBR Green technique, and 2 (0.9%) only by TaqMan probe technique. Forty (20.4%) of the 196 chronic HCV cases were HCV-RNA positive by SYBR Green but negative by TaqMan probe technique.Conclusion: This method is useful for rapid qualitative detection of HCV infection and particularly suitable for routine diagnostic applications.Keywords: HCV, PCR, SYBR Green 1, TaqMan probe, Viral loa

Cranio-Cervical Idiopathic Hypertrophic Pachymeningitis: A Case Report and Review of Literature

Background Data: Cranio-cervical pachymeningitis is a rare and challenging disorder. Management of this condition is still under research. Purpose: To follow a case of cranio-cervical pachymeningitis and to decide the optimal management method and factors affecting outcome and prognosis of this condition. Study Design: A case report following surgical result with review of literatures. Patients and Methods: A 56 years old male presented by a progressive cervical myelopathy. MRI cervical spine showed cranio-cervical hypertrophic pachymeningitis with compression on cervical cord. Surgical decompression was done with continuous postoperative clinical and radiological follow-up. Results: Significant clinical improvement was observed after surgical excision. Recurrence happened later with cessation of corticosteroids. After follow up of the patient and review of literatures; factors affecting the prognosis were determined as follow: degree of surgical decompression, continuous use of corticosteroids till full radiological improvement, and development of cranial lesions. Conclusion: Cranio-cervical pachymeningitis is a challenging disorder, management of it should be combined adequate surgical decompression, use of corticosteroids and postoperative rehabilitation program. (2016ESJ116

Posterior Revision of Lumbar Interbody Fusion Cages Migration: Clinical Case Series and Literature Review

Background Data: Revision surgery for lumbar interbody cage migration is technically demanding.Cage related complication may lead to failure of fusion. Revision of such morbidity is associated with increased risk of permanent neurological insult. Purpose: To analyze the efficacy of posterior approach and iliac crest auto grafting technique in revision of migrated intervertebral cages. Study Design: Retrospective descriptive clinical case study. Patients and Methods: From January 2010 to January 2016, we operated 106 patients underwent posterior lumbar interbody fusion (PLIF) with single cage application per level for treatment of degenerative spondylolisthesis. Of these, 12 patients experiencing cage subsidence and retropulsion. In subsidence, it was graded from 0 to III. Retropulsion was considered if the cage beyond the level of the posterior longitudinal line of the index two vertebrae. Patients were assessed pre-operatively for pain and clinical functional outcome by visual analogue scale (VAS) and Oswestry disability index (ODI), respectively. Patient with VAS score ≥5; at least 20% deterioration on ODI or with the superadded neurological deficit was considered candidates for revision surgery. Results: Cage migration incidence was 11.3%, with subsidence (6.7%), and retropulsion (4.6%) of all patients. The average time for subsidence was 3.3 months (range 2 to 6 months). Five patients with grade-II and III subsidence underwent revision surgery for foraminal decompression, augmenting fixation and adding postero-lateral iliac crest bone graft. Retropulsion was encountered in 4 patients and all needed revision surgery for cage retrieval and redo fusion. Grade-I subsidence could be treated conservatively. All surgically treated patients had a good result in VAS and ODI after a second surgery which maintained during follow up with P<0.05. Conclusion: Migration of posterior lumbar interbody fusion cage into the endplates or spinal canal is usually associated with patient dissatisfaction. Revision surgery indicated for cage retropulsion or high-grade subsidence. The posterior approach is technically demanding, safe, and effective for cage migration revision surgery. (2017ESJ141

Pedicle Screw-Related Complications in Thoracolumbar and Lumbosacral Spine Surgery

Background Data: Pedicle screw instrumentation of the thoracolumbar and lumbosacral spine is a well-known technique used to achieve rigid fixation for a wide variety of spinal disorders. However, it is technically demanding and may be associated with potential operative risks and complications. Study Design: A retrospective clinical case study. Purpose: To determine the incidence of complications related to pedicle screw fixation of thoracolumbar and lumbosacral spine, and if it affects the final decision of the surgeons. Patients and Methods: The reported complications in 108 transpedicular thoracolumbar and lumbosacral fixation procedures were analyzed. All medical files, operative notes, and radiographs were examined. Results: Varied complications were observed in 35.2% of patients during and after surgery. General complications were found in 13.8%, most were trivial. Infection rate was 4.6%, all cured with antibiotics except one patient who required screws removal. Neurological complications were noted in 2.7% of patients. Transient root paresis developed in 1 patient due to pedicle wall perforation. Radicular pain was noted in one patient secondary to irritation from misplaced screw. Dural tears were reported in 0.9% of our patients during screws insertion. None of patients developed permanent deficit. Device-related complications occurred in 18.5% of patients, 55% of them occurred at thoracolumbar junction. Screw false passage was seen intra-operatively in 4.6%, pedicle fracture in 0.9%. Misplaced screw was reported in 5.5% and screw breakage in 3.7% of patients. Screw breakage occurred mainly in multi-level procedures which did not involve anterior column restoration (P<0.001). Conclusion: Pedicle screws instrumentation is associated with significant complication rate. However, most complications are trivial and can be avoided through applying careful operative techniques and awareness of spinal anatomy. (2016ESJ118

Peri-operative Radiological Factors Predicting Outcome of Discogenic Cauda Equina Syndrome

Background Data: Acute cauda equina syndrome (CES) is a rare disorder considered as a neurosurgical emergency. It can be devastating in some circumstances. Outcome can be predicted by certain preoperative radiological and clinical items. Purpose: To evaluate and analyse the effect of radiological criteria either pre- or postoperative on the final outcome of acute cauda equina syndrome. Study Design: A prospective clinical case study on 27 patients who were presented by manifestations of CES from May 2014 to September 2017. Patients and Methods: Between May 2014 to May 2017 a total of 27 consecutive patients with discogenic acute cauda equina syndrome underwent decompressive surgery (laminectomy and discectomy) with a follow-up at 6 and 12 months postoperative. Preoperative and postoperative clinical assessments were done by using Visual Analogue Scale (VAS) for analysing pain and full neurological examination. Surgical outcome was assessed using Oswestry Disability Index (ODI) and Japanese Orthopedic Association (JOA) scale. Recovery rate (RR) was calculated in final follow up for each patient. In all cases, preoperative and at the last follow-up control a neuro-radiographic MRI assessment was done. Level of affection, size and direction of prolapsed disc, presence of lumbar canal stenosis, degree of decompression (laminectomy), and the presence of disc residual disc, were all thoroughly analyzed with evaluating the correlation with clinical outcome. Results: At final follow-up visit, we found that radiological factors had significant effect on the overall clinical outcome. L5-S1 disc level had the most favourable outcome when compared to other affected level. A statically significant correlation was found between degree of decompression and overall clinical improvement (P=0.001). Residual disc fragments had a direct relation to incomplete recovery from preoperative symptoms although statistically insignificant (P=0.93). Conclusion: Full and thorough study of the pre- and postoperative radiological findings of the patients presented with discogenic cauda equina syndrome has an important prognostic value that can give a prediction for the surgical outcome and the overall clinical improvement. The degree of decompression and presence of canal stenosis was the most important outcome predictor factors. (2017ESJ148

Gait Trajectory Prediction on an Embedded Microcontroller Using Deep Learning

Achieving a normal gait trajectory for an amputee’s active prosthesis is challenging due to its kinematic complexity. Accordingly, lower limb gait trajectory kinematics and gait phase segmentation are essential parameters in controlling an active prosthesis. Recently, the most practiced algorithm in gait trajectory generation is the neural network. Deploying such a complex Artificial Neural Network (ANN) algorithm on an embedded system requires performing the calculations on an external computational device; however, this approach lacks mobility and reliability. In this paper, more simple and reliable ANNs are investigated to be deployed on a single low-cost Microcontroller (MC) and hence provide system mobility. Two neural network configurations were studied: Multi-Layered Perceptron (MLP) and Convolutional Neural Network (CNN); the models were trained on shank and foot IMU data. The data were collected from four subjects and tested on a fifth to predict the trajectory of 200 ms ahead. The prediction was made for two cases: with and without providing the current phase of the gait. Then, the models were deployed on a low-cost microcontroller (ESP32). It was found that with fewer data (excluding the current gait phase), CNN achieved a better correlation coefficient of 0.973 when compared to 0.945 for MLP; when including the current phase, both network configurations achieved better correlation coefficients of nearly 0.98. However, when comparing the execution time required for the prediction on the intended MC, MLP was much faster than CNN, with an execution time of 2.4 ms and 142 ms, respectively. In summary, it was found that when training data are scarce, CNN is more efficient within the acceptable execution time, while MLP achieves relative accuracy with low execution time with enough data

Variations in external carotid artery branches and common carotid bifurcation level: a computed tomography angiography study

Abstract Background The common carotid bifurcation level is an important surgical landmark during head and neck surgery, especially endarterectomy, that could be omitted in patients with high bifurcation levels to reduce damage to neighboring structures like the hypoglossal nerve. Additionally, having a thorough understanding of the variations in the external carotid artery branches is crucial for head and neck cancer surgeries and thyroidectomy. However, cadavers were employed in the majority of studies on these variations. In previous research, there were significant disparities in the incidence of these variations according to gender, laterality, and ethnicity. In order to identify these changes in Egyptian patients and to compare them in terms of gender and laterality, we used computed tomographic angiography. Methods The level of the common carotid bifurcation was assessed in a cross-sectional study utilizing computed tomographic angiography, which included 80 patients (160 carotid sides) for comparing the common carotid artery bifurcation level with the relevant vertebrae and anterior neck structures, and they were compared with regard to gender and laterality. Variations in the external carotid artery branches were also evaluated. Results The most frequent location of the common carotid bifurcation level was between C3 and C4 (33.8%). It was 36.9% between the thyroid and the hyoid. 47.5% of patients had a high common carotid bifurcation (higher than the C3/4 level). The highest bifurcation was at C2, while the lowest was at D1. For external carotid artery branches variations, the superior thyroid artery emerged at and below the level of the common carotid bifurcation, respectively, at 19.4% and 23.7%. The facial artery had the largest diameter (2.38 ± 0.44 mm), while the ascending pharyngeal artery had the smallest (1.17 ± 0.11 mm). Seven types of trunks were found; the ascending pharyngeal artery-occipital artery trunk was the most common (25%) and was followed by the lingual artery-facial artery trunk (20%). Conclusions Multiple anatomical variations in the external carotid artery branches and the common carotid bifurcation level were found by computed tomographic angiography. As a result, it can be utilized as a useful imaging technique to evaluate these variations before surgery

Impact of occult hepatitis B virus infection on antiviral therapy in chronic hepatitis C patients

Background: Occult HBV infection (OBI) can be defined by the presence of HBV-DNA in the serum of patients who are negative for HBsAg. The presence of OBI has been associated with a poor therapeutic response to alpha IFN in many, but not in all studies. Objective: The aim of our study was to assess the prevalence of OBI in the serum of Egyptian patients with CHC, and to evaluate its impact on the response to treatment with a combination of Peg-IFNα and RBV. Materials and methods: Fifty chronic HCV infected patients who were treated with Peg-IFNα once a week in combination with RBV for 48 weeks were included in this study. Patients were divided into two groups, group I which included 25 patients who achieved SVR and group II that included 25 patients who failed to achieve SVR (Non-SVR). Both patient groups were subjected to detailed questionnaire, clinical examination, routine laboratory investigations and virological studies. Results: No statistical significant difference was found in sex distribution regarding SVR and Non-SVR. The frequency of patients with low viral load has a statistically significant association with SVR patients compared to Non-SVR patients. The frequency of anti-HBc seropositivity has a statistically significant association with the Non-SVR patients compared to SVR patients. Out of 11 anti-HBc positive samples, 10 (90.9%) were positive for the pol and s genes while 9 (81.81%) were positive for the c gene. About 17 (34%) out of 50 patients included in the study were HBV-DNA positive. The frequency of HBV-DNA positive HCV patients has a statistically significant association with Non-SVR patients compared to the SVR patients (p < 0.05). Conclusion: The prevalence of OBI was higher in our CHCV patients. OBI was significantly associated with poor response to combined Peg-IFNα and RBV therapy