Are deformed neurons electrophysiologically altered? A simulation study

Tahereh Tekieh,Sohrab Shahzadi,Hashem Rafii-Tabar,Pezhman Sasanpour 한국물리학회 2016 Current Applied Physics Vol.16 No.10

The electrophysiological outcome of neuron deformation is studied. This study is based on modeling the propagation of action potentials in a neuron with different deformed segments subject to an external mechanical compression. The proposed model is based on modified cable equation incorporating geometry variations. The study is performed for different degrees and number of deformations of the axon structure. The results of simulation show that the propagation speed, the refractory period, and the action potential broadening are all directly affected by variations in the geometry.

Decision-Making Process in Patients with Thoracolumbar and Lumbar Burst Fractures with Thoracolumbar Injury Severity and Classification Score Less than Four

Shirzad Azhari,Parisa Azimi,Sohrab Shahzadi,Hassan Reza Mohammadi,Hamid Reza Khayat Kashani 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.1

Study Design: Cross-sectional. Purpose: To develop a strategy to determine a sound method for decision-making based on postoperative clinical outcome satisfaction. Overview of Literature: The ideal management of thoracolumbar and lumbar burst fractures (TLBF) without neurological compromise remains controversial. Methods: This was a prospective study. Patients with thoracolumbar injury severity and classification score (TLICS) <4 were treated nonoperatively, with bed rest and bracing until the pain decreased sufficiently to allow mobilization. Surgery was undertaken in patients with intractable pain despite an appropriate nonoperative treatment (surgery group). The Oswestry disability index (ODI) measure was observed at baseline and at the last follow-up. Clinically success was defined at least a 30% improvement from the baseline ODI scores in both the conservative and surgery groups. All case records were assessed for gender, age, residual canal and angulations at the site of the fracture in order to determine which patients benefited from surgery or conservative treatment and which did not. Results: In all 113 patients with T11–L5, TLBFs were treated. The patients’ mean age was 49.2 years. Patients successfully completed either nonoperative (n=99) or surgical (n=14) treatment based on ODI. Clinical examinations revealed that all of the patients had intact neurology. The mean follow-up period was 29.5 months. There was a significant difference between the two groups based on age and residual canal. The mean ODI score significantly improved for both groups (p <0.01). According to the findings, a decision matrix was proposed. Conclusions: The findings confirm that TLICS <4, age, and residual canal can be used to guide the treatment of TLBF in conservative decision-making.

Cut-off Value for Body Mass Index in Predicting Surgical Success in Patients with Lumbar Spinal Canal Stenosis

Parisa Azimi,Taravat Yazdanian,Sohrab Shahzadi,Edward C. Benzel,Shirzad Azhari,Hossein Nayeb Aghaei,Ali Montazeri 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.6

Study Design: Case-control. Purpose: To determine optimal cut-off value for body mass index (BMI) in predicting surgical success in patients with lumbar spinal canal stenosis (LSCS). Overview of Literature: BMI is an essential variable in the assessment of patients with LSCS. Methods: We conducted a prospective study with obese and non-obese LSCS surgical patients and analyzed data on age, sex, duration of symptoms, walking distance, morphologic grade of stenosis, BMI, postoperative complications, and functional disability. Obesity was defined as BMI of ≥30 kg/m2. Patients completed the Oswestry Disability Index (ODI) questionnaire before surgery and 2 years after surgery. Surgical success was defined as ≥30% improvement from the baseline ODI score. Receiver operating characteristic (ROC) analysis was used to estimate the optimal cut-off values of BMI to predict surgical success. In addition, correlation was assessed between BMI and stenosis grade based on morphology as defined by Schizas and colleague in total, 189 patients were eligible to enter the study. Results: Mean age of patients was 61.5±9.6 years. Mean follow-up was 36±12 months. Most patients (88.4%) were classified with grades C (severe stenosis) and D (extreme stenosis). Post-surgical success was 85.7% at the 2-year follow-up. A weak correlation was observed between morphologic grade of stenosis and BMI. Rates of postoperative complications were similar between patients who were obese and those who were non-obese. Both cohorts had similar degree of improvement in the ODI at the 2-year followup. However, patients who were non-obese presented significantly higher surgical success than those who were obese. In ROC curve analysis, a cut-off value of ≤29.1 kg/m2 for BMI in patients with LSCS was suggestive of surgical success, with 81.1% sensitivity and 82.2% specificity (area under the curve, 0.857; 95% confidence interval, 0.788–0.927). Conclusion: This study showed that the BMI can be considered a parameter for predicting surgical success in patients with LSCS and can be useful in clinical practice.

Outcome Measure of Pain in Patients with Lumbar Disc Herniation: Validation Study of the Iranian version of Pain Sensitivity Questionnaire

Parisa Azimi,Shirzad Azhari,Sohrab Shahzadi,Hossain Nayeb Aghaei,Hassan Reza Mohammadi,Ali Montazeri 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.3

Study Design: Cross-sectional. Purpose: To translate and culturally adapt an Iranian version of the Pain Sensitivity Questionnaire (PSQ) in Iran. Overview of Literature: Instruments measuring patient reported outcomes should satisfy certain psychometric properties. Methods: The PSQ was translated following cross-cultural adaptation guidelines. A total of 101 patients with lumbar disc herniation (LDH), and 39 healthy cases were included in the study. All participants completed the PSQ and the Pain Catastrophizing Scale (PCS). The internal consistency, test-retest reliability, known group comparison, criterion validity and item-scale correlations were assessed. Results: The mean age of participants was 51.7 years. Reliability, validity and correlation of PSQ and PCS showed satisfactory results. Cronbach’s alpha coefficients were 0.81 for PSQ-total, 0.82 for PSQ-minor, and 0.82 for PSQ-moderate. The intraclass correlation coefficients value was 0.84 (0.616–0.932) indicating an excellent test-retest reliability. The instrument discriminated well between sub-groups of patients who differed in a standard predictive measure of LDH surgery (the Finneson–Cooper score). Total PSQ were also significantly correlated with the total scores of the PCS, lending support to its good convergent validity. Additionally, the correlation of each item with its hypothesized domain on the PSQ indicated acceptable results, suggesting that the items had a substantial relationship with their own domains. Conclusions: The adapted Iranian PSQ is a valid and reliable questionnaire for the assessment of pain in patients with LDH.

Role of the Self-Administered, Self-Reported History Questionnaire to Identify Types of Lumbar Spinal Stenosis: A Sensitivity Analysis

Hossein Nayeb Aghaei,Parisa Azimi,Sohrab Shahzadi,Shirzad Azhari,Hassan Reza Mohammadi 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.5

Study Design: Case-control design. Purpose: To evaluate the role of the self-administered, self-reported history questionnaire (SSHQ) in identifying types of lumbar spinal stenosis (LSS). Overview of Literature: Diagnosis of types of LSS is controversial. Methods: A total of 235 patients with LSS were asked to respond to the SSHQ. All of these patients recovered following surgical treatment. The classification of LSS patients was based on history, physical examinations, and imaging studies. It is considered to be the gold standard. Radicular and neurogenic claudication types of LSS were based on the SSHQ developed by Konno et al. Two categories of LSS were determined based on the SSHQ tool and gold standard. Finally, a sensitivity analysis was carried out to evaluate the diagnostic value of the SSHQ. Results: The mean age of patients was 59.4 years. According to the criteria for gold standard, patients were diagnosed with the radicular type (n=103), and neurogenic claudication type (n=132). The questionnaire had desirable sensitivity, specificity, and accuracy in categorizing the two types of LSS: 97.8%, 66.6%, and 96.8% for the radicular type, and 97.0%, 80.0%, and 95.7% for the neurogenic claudication type. Conclusions: Our findings indicate that the SSHQ is a reliable and a valid measure and it may be a clinical diagnosis support tool for identifying patients with two types of LSS.

Outcome Measures of Functionality, Social Interaction, and Pain in Patients with Cervical Spondylotic Myelopathy: A Validation Study for the Iranian Version of the Copenhagen Neck Functional Disability Scale

Hossein Nayeb Aghaei,Parisa Azimi,Sohrab Shahzadi,Shirzad Azhari,Hassan Reza Mohammadi,Pooyan Alizadeh,Ali Montazeri 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.6

Study Design: Cross-sectional. Purpose: To translate and validate the Iranian version of the Copenhagen Neck Functional Disability Scale (CNFDS). Overview of Literature: Instruments measuring patient-reported outcomes should satisfy certain psychometric properties. Methods: Ninety-three cases of cervical spondylotic myelopathy were entered into the study and completed the CNFDS pre and postoperatively at the 6 month follow-up. The modified Japanese Orthopedic Association Score was also completed. The internal consistency, test-retest, convergent validity, construct validity (item scale correlation), and responsiveness to change were assessed. Results: Mean age of the patients was 54.3 years (standard deviation, 8.9). The Cronbach α coefficient was satisfactory (α=0.84). Test-retest reliability as assessed by the intraclass correlation coefficient analysis was 0.95 (95% confidence interval, 0.92–0.98). The modified Japanese Orthopedic Association score correlated strongly with the CNFDS score, lending support to its good convergent validity (r =−0.80; p <0.001). Additionally, the correlation of each item with its hypothesized domain on the CNFDS was acceptable, suggesting that the items had a substantial relationship with their own domains. These results also indicate that the instrument was responsive to change (p <0.0001). Conclusions: The findings suggest that the Iranian version of the CNFDS is a valid measure to assess functionality, social interaction, and pain among patients with cervical spondylotic myelopathy.

Lumbar Spinal Canal Stenosis Classification Criteria: A New Tool

Parisa Azimi,Hassan Reza Mohammadi,Edward C. Benzel,Sohrab Shahzadi,Shirzad Azhari 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.3

Study Design: Case-control study. Purpose: To design a new tool for classifying lumbar spinal canal stenosis (CLSCS). Overview of Literature: Grading of patients with lumbar spinal canal stenosis (LSCS) is controversial. Methods: The Oswestry disability index (ODI) and the neurogenic claudication outcome score (NCOS) were recorded. Four parameters, which indicate the severity of LSCS disease, including Hufschmidt-grade, grading of magnetic resonance imaging, self-paced walking test, and stenosis ratio (SR) were employed. For the SR, quartile analysis was applied for classifying LSCS and the Hufschmidt- grade was modified into a 4-grade score. An initial score was assigned to each metric based on the severity of LSCS. Using the inverse-variance weighting method, the relative weights of these domains and their categories were determined. The score for all of the cases was obtained based on their weight by summing up the points of the four variables. Quartile analysis was used and a CLSCS score was proposed. Finally, intra- and interobserver reliability, and validity were assessed. Results: A total of 357 patients were studied. The final CLSCS score for each case ranged from 4 to 16.5. Based on the quartile analysis, using the new criteria set, the CLSCS score was divided into four categories: CLSCS<7 (grade 0); 7≤CLSCS<10 (grade 1); 10≤CLSCS<13 (grade 2); and 13≤CLSCS≤16.5 (grade 3). The kappa values of for the CLSCS score indicated a perfect agreement. The CLSCS was correlated with the ODI and NCOS. All patients with grade 3 CLSCS were observed in the surgical group. Conclusions: The CLSCS score can be helpful for classifying LSCS patients and in the decision-making process.