hassan mohammadi | University of Tehran (original) (raw)
Papers by hassan mohammadi
Http Dx Doi Org 10 1080 00036840600707274, Apr 11, 2011
This paper address the extent of capital mobility and foreign debt sustainability in Turkey over ... more This paper address the extent of capital mobility and foreign debt sustainability in Turkey over the 1962–2003 period by examining the relationship between saving and investment, and imports and exports, respectively. The empirical investment is based on cointegration, error correction models, and threshold and momentum threshold autoregressive models. Our findings are consistent with the existence of capital mobility and the
Journal of Clinical Neuroscience, 2016
Endoscopic third ventriculostomy (ETV) is an alternative to ventriculoperitoneal shunting for tre... more Endoscopic third ventriculostomy (ETV) is an alternative to ventriculoperitoneal shunting for treatment of hydrocephalus. Studies have reported favorable outcomes for up to three-quarters of adult patients. We performed the first ETV outcomes study using an administrative claims database, examining current practice for adult patients in the United States. We interrogated the Truven Health MarketScan® database for Current Procedural Terminology codes corresponding to ETV and ventriculoperitoneal shunt from 2003- to 2011, including patients over 18years and data from initial and subsequent hospitalizations. ETV failure was defined as any subsequent ETV or shunt procedure. Five hundred twenty-five patients underwent ETV with 6months minimum follow-up. Mean age was 45.9years (range: 18-86years). Mean follow-up was 2.2years (SD: 1.6years, range: 0.5-8.4years). Etiology of hydrocephalus was 21.3% tumor, 9.0% congenital/aqueductal stenosis, 15.8% hemorrhage, and 53.9% others. ETV was successful in 74.7% of patients. Of 133 who failed, 25 had repeat ETV; 108 had shunt placement. Longer length of stay for index surgery was associated with higher risk of failure (hazard ratio (HR): 1.03, p<0.001), as was history of previous shunt (HR: 2.45, p<0.001). Among patients with repeat surgeries, median time to failure was 25days. This study represents a longitudinal analysis of nationwide ETV practice over 9years. Success rate in this large cohort is similar to that published by other single-center retrospective studies. Age and geographic variation may be associated with surgeon choice of ETV or shunt placement after failure of the initial ETV.
Journal of Research in Medical Sciences, Jan 4, 2014
Asian Spine Journal, 2016
Cross-sectional. To translate and culturally adapt an Iranian version of the Pain Sensitivity Que... more Cross-sectional. To translate and culturally adapt an Iranian version of the Pain Sensitivity Questionnaire (PSQ) in Iran. Instruments measuring patient reported outcomes should satisfy certain psychometric properties. 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. 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. The adapted Iranian PSQ is a valid and reliable questionnaire for the assessment of pain in patients with LDH.
Asian Spine Journal, 2016
Cross-sectional. Clinical outcome study comparing the Copenhagen Neck Functional Disability Scale... more Cross-sectional. Clinical outcome study comparing the Copenhagen Neck Functional Disability Scale (CNFDS) and modified Japanese orthopedic association (mJOA) assessment scales in patients with cervical spondylotic myelopathy (CSM). Comparison of instruments that measure patient-reported outcomes is needed. A cross-sectional analysis was conducted. Ninety five patients with CSM were entered into the study and completed the CNFDS and the mJOA preoperatively and postoperatively. Correlation between the CNFDS and the mJOA was evaluated preoperatively and at the end of follow-up. Responsiveness to change of CNFDS and mJOA was also assessed. Clinical outcomes were also measured with the recovery rate of mJOA score at end of follow-up. The mean age of patients was 58.2 (standard deviation, SD=8.7) years. Mean follow-up was 2.1 years (range, 1 to 4 years). The mJOA correlated strongly with the CNFDS score preoperatively and postoperatively (r=-0.81 and -0.82, respectively; p<0.001). The CNFDS and the mJOA were able to detect changes after the surgery (p<0.001). The mean mJOA recovery rate was 51.8% (SD=13.1%). Surgery for the treatment of patients with CSM is an efficacious procedure. CNFDS and mJOA scores have a strong correlation in measuring disability among CSM patients.
PLOS ONE, 2016
The aim of the study was to compare outcome of surgery in patients with lumbar canal stenosis (LC... more The aim of the study was to compare outcome of surgery in patients with lumbar canal stenosis (LCS) based on magnetic resonance imaging (MRI) morphology. This was a prospective study of 96 consecutive patients who underwent surgery at 143 levels of LCS (from L3-L4 to L5-S1). Using patterns on T2 axial MRI, the type of stenosis was determined for each patient. The Swiss Spinal Stenosis Score (SSS) was used to evaluate patients' functionality and outcomes. The definition of treatment success was based on the criteria developed by Stucki et al. Demographic characteristics and post-operative outcomes were compared between trefoil, triangular, and pin-hole groups. Finally, correlation between SSS score and the MRI morphology was assessed. The mean age of patients was 58.4 (SD = 8.9) years. Post-treatment satisfaction was observed in a large portion of the patients (87.5%). The trefoil group (n = 44), triangular group (n = 38), and pin-hole group (n = 14) had similar pre-operative Swiss Spinal Stenosis Score and were not significantly different in age, operative time, blood loss, duration of symptoms, walking distance, symptom severity and physical function (all p>0.4). No correlation between SSS score and the MRI morphology was observed. The findings suggest that the type of stenosis based on magnetic resonance imaging morphology is not indicative of surgical outcome among lumbar canal stenosis patients who undergo surgery at 1-year follow-up.
Asian Spine Journal, 2016
Cross-sectional. To develop a strategy to determine a sound method for decision-making based on p... more Cross-sectional. To develop a strategy to determine a sound method for decision-making based on postoperative clinical outcome satisfaction. The ideal management of thoracolumbar and lumbar burst fractures (TLBF) without neurological compromise remains controversial. 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. 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. The findings confirm that TLICS <4, age, and residual canal can be used to guide the treatment of TLBF in conservative decision-making.
Asian spine journal, 2015
Cross-sectional. To translate and validate the Iranian version of the Copenhagen Neck Functional ... more Cross-sectional. To translate and validate the Iranian version of the Copenhagen Neck Functional Disability Scale (CNFDS). Instruments measuring patient-reported outcomes should satisfy certain psychometric properties. 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. 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....
Asian Spine Journal, 2015
Case-control design. To evaluate the role of the self-administered, self-reported history questio... more Case-control design. To evaluate the role of the self-administered, self-reported history questionnaire (SSHQ) in identifying types of lumbar spinal stenosis (LSS). Diagnosis of types of LSS is controversial. 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. 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. 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.
Background and Purpose: Decision-making process in Thoracolumbar and Lumbar Burst Fracture (TLBF)... more Background and Purpose: Decision-making process in Thoracolumbar and Lumbar Burst Fracture (TLBF) patients with Thoracolumbar Injury Severity and Classification Score (TLICS) > 4 is remained controversial. On the other hand, the question is whether that the Oswestry Disability Index (ODI) can be use to assess to clinical outcomes in these patients. We aimed to study the correlation between the ODI and American Spinal Injury Association (ASIA) impairment scale in these patients and evaluation of surgical outcome. Methods: This was a prospective study. The TLICS were determined and TLICS > 4 was included. The nerve injury was assessed according to sensory scores and motors scores of the using ASIA Scale at pre- and postoperative. It was also ODI calculated at last follow-up. In addition, correlation between ASIA and ODI was evaluated at last follow-up. Results: Fifty eight patients (20.7% female) who underwent spinal surgery for TLBF with a minimum follow up of 2 years were stud...
Asian Spine Journal, 2015
Case-control study. To design a new tool for classifying lumbar spinal canal stenosis (CLSCS). Gr... more Case-control study. To design a new tool for classifying lumbar spinal canal stenosis (CLSCS). Grading of patients with lumbar spinal canal stenosis (LSCS) is controversial. 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. 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. The CLSCS score can be helpful for classifying LSCS patients and in the decision-making process.
Journal of neurosurgical sciences, Jan 11, 2014
A lack of consensus exists regarding indications for surgery for lumbar spinal canal stenosis (LS... more A lack of consensus exists regarding indications for surgery for lumbar spinal canal stenosis (LSCS). Hence, the aim of this study is to develop an artificial neural network (ANN) model that is designed to accurately select patients for surgery or non--surgical options and to compare such with the traditional clinical decision making approach in LSCS patients. An ANN model and a logistic regression (LR) model were used as predicting models. The data for a total of 346 of 379 patients (143 male, 203 female, mean age 59.5±11.5 years) were available for the analysis. The measured metrics included visual analog scale (VAS) of leg pain/numbness, the Japanese Orthopaedic Association (JOA) Score, the Neurogenic Claudication Outcome Score (NCOS), the Oswestry disability index (ODI), the Swiss Spinal Stenosis Score (SSS), the stenosis bothersomeness index (SBI), the dural sac cross--sectional surface area (DSCA), the Stenosis Ratio (SR), the Self--Paced Walking Test (SPWT), morphology grade ...
Journal of neurosurgical sciences, 2014
A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score ... more A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score (SSS) is a well-known questionnaire that measures the severity of symptoms, physical functioning and patient's satisfaction in lumbar spinal stenosis. This study aimed to translate and validate the SSS in Iran. A prospective clinical validation study was performed. Forward-backward procedure was applied to translate the original questionnaires into Persian. A sample of patients with lumbar spinal stenosis completed the questionnaire twice: at pre- and postoperative (6 months follow-up) assessments. To test reliability the internal consistency was assessed by the Cronbach's alpha coefficient. Validity was evaluated using the known groups comparison. In addition the Oswestry Disability Index was used to perform convergent validity. In all 121 patients were entered into the study. The mean age of patients was 62.3 (SD=10.2) years. The Cronbach's alpha coefficient for the SSS was...
Purpose: This study aimed to correlation between the grading stenosis and the STarT Back Screenin... more Purpose: This study aimed to correlation between the grading stenosis and the STarT Back Screening Tool (SBST) in patients diagnosed with lumbar central canal stenosis (LCCS). Methods: In a prospective clinical study, a total of 269 patients with LCCS were asked to respond to the questionnaire at their first visits. Grading of LCCS on MRI was determined and also the severities of the disease were observed based on SBST as the gold standard. Finally grading on MRI and calcification of the SBST were determined, and sensitivity analysis carried out to evaluate severity of LCCS on grading of MRI using the SBST. Results: The mean age of patients was 58.6 (SD= 10.9) years; and 56.5% were female. According to patients’ imaging they have been diagnosed as grade 1 (n = 86), grade 2 (n = 107) and grade 3 (n = 76). The sensitivity, specificity and accuracy of the estimated grading of LCCS on MRI for low, medium, and high risk groups were found to be desirable: 97.6%, 66.7%, 96.5% for low risk;...
Purpose: This study investigated functionality statues and surgical outcome of patients with cerv... more Purpose: This study investigated functionality statues and surgical outcome of patients with cervical spondylotic myelopathy (CSM) contains cervical herniated disc (CHD) and cervical spinal stenosis (CSS) based on the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). Methods: This was a prospective clinical study a sample of cases with CSM. Patient’s functionality statues and surgical outcome were evaluated based on JOACMEQ scores at two points in time: pre- and postoperative assessments. Results: In all 87 patients were completed the JOACMEQ measure. The mean age of patients was 50.3 (SD=10.2) years. The mean clinical follow-up was 12 months (range 7-37 months). Statistically difference between was observed pre- and postoperative indicating improvements on the outcomes and functionality in all subscales (P < 0.001). However, there was no significant difference between patients with CSM and CHD. Conclusion: The findings suggest that surgery i...
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, 2012
Lumbar disc hernia (LDH) is a common cause of low back pain and radicular leg pain. The Japanese ... more Lumbar disc hernia (LDH) is a common cause of low back pain and radicular leg pain. The Japanese Orthopedic Association (JOA) score is a very short instrument for measuring functionality and pain in these patients. This study aimed to translate and validate the JOA score for use in Iran. This was a prospective clinical validation study. Translation of the English version of the questionnaire was performed in accordance with published guidelines. A sample of patients with LDH was asked to respond to the questionnaire at two points in time--at preoperative and postoperative (6 months follow-up) assessments. To test reliability, the internal consistency was assessed by use of Cronbach's alpha coefficient. Validity was evaluated by use of known-groups comparison. A total of 117 patients with LDH were entered into the study. The mean age of patients was 45 (SD = 11) and Cronbach's alpha coefficients for the JOA score at the preoperative and postoperative assessments were 0.67 and...
Materia Socio Medica, 2014
Introduction: For almost fifteen years, the application of computer in hospitals increasingly has... more Introduction: For almost fifteen years, the application of computer in hospitals increasingly has become popular. Nurses' beliefs and attitudes towards computer is one of the most important indicators of the application of nursing information system. The purpose of this study was to investigate the perceptions of nurses on the usefulness of nursing information system for patient care. Methods: Here, a descriptive study was carried out. Sample was consisted of 316 nurses working in teaching hospitals in an urban area of Iran. This study was conducted during 2011 to 2012. A reliable and valid questionnaire was developed as a data collection tool. The collected data was analyzed using descriptive and inferential statistics. Results: It was not believed that nursing information system was useful for patient care. However, it was mentioned that nursing information system is useful in some aspects of patient care such as expediting care, making early diagnosis and formulating diet plan. A significant association was found between the demographic background of sample and their perceptions of the usefulness of nursing information system (P<0.05). Conclusion: Totally, it can be concluded that nursing information system has a potential for improving patient care in hospital settings. Therefore, policy makers should consider implementing nursing information system in teaching hospitals.
2008 International Conference on Microelectronics, 2008
The increasing rate of transient faults necessitates the use of on-chip fault-tolerant techniques... more The increasing rate of transient faults necessitates the use of on-chip fault-tolerant techniques in embedded microprocessors. Performance overhead is a challenging problem in on-chip fault-tolerant techniques used in the random logic of the embedded microprocessors. This paper presents a signaturebased error detection and roll-back recovery technique for the control logic with much lower performance overhead as compared to many previous techniques. The low performance overhead is achieved by eliminating the fault masking overhead cycles in the previous techniques. The performance overhead is analytically studied, and the analytical results recommend at which fault rate the use of the technique is preferred. To measure the cycle time of the pipeline critical path and area overhead, this technique has been implemented and synthesized using a behavioral VHDL model of the Leon2 processor. The synthesis results show that the area and the cycle time overhads of the technique are only 17.7% and 3.4%, respectively. In addition, the injection of about 74000 transient single bit-flip faults into the control logic part of the Leon2 processor shows that the technique detected about 99% of the injected faults.
Journal of Spinal Disorders and Techniques, 2014
The aim of this study was to develop an artificial neural network (ANN) model to predict recurren... more The aim of this study was to develop an artificial neural network (ANN) model to predict recurrent lumbar disk herniation (LDH). An ANN model and a logistic regression model were used to predict recurrent LDH. The age, sex, duration of symptoms, smoking status, recurrent LDH, level of herniation, type of herniation, sports activity; occupational lifting, occupational driving, duration of symptoms, visual analog scale (VAS), the Zung Depression Scale (ZDS), and the Japanese Orthopaedic Association (JOA) Score, were determined as the input variables for the established ANN model. The Macnab classification, VAS, and JOA were used for outcome assessment. ANNs on data from LDH patients, who underwent surgery, were trained to predict LDH using several input variables. The patients were divided into a recurrent LDH group (R group) and a primary LDH group (P group). Sensitivity analysis was applied to identify the relevant variables. The receiver-operating characteristic curve, accuracy rate of predicting, and Hosmer-Lemeshow statistics were considered for evaluating the 2 models. A total of 402 patients were categorized into training, testing, and validation data sets consisting of 201, 101, and 100 cases, respectively. The recurrence rate was 8.7%, and the median time to recurrence was 26.2 months (SD=4 mo). The VAS of leg/back pain and JOA were improved at 1-year follow-up (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and no significant difference was observed between the 2 groups. Surgical successful outcome was categorized as: excellent, 31.1%; good, 44.3%; fair, 18.9%; and poor, 5.7% at 1-year follow-up. Compared with the logistic regression model, the ANN model was associated with superior results: accuracy rate, 94.1%; Hosmer-Lemeshow statistic, 40.2%; and area under the curve, 0.83% of patients. The findings show that an ANNs can be used to predict the diagnostic statues of recurrent and nonrecurrent group of LDH patients before the first or index microdiscectomy.
SSRN Electronic Journal, 2000
ABSTRACT This paper analyzes market index returns in the Tehran stock exchange (TSE) within the c... more ABSTRACT This paper analyzes market index returns in the Tehran stock exchange (TSE) within the context of three variants of the Capital Asset Pricing Model: the static international; the constant-parameter intertemporal; and a Markov-switching intertemporal CAPM, which allows for the degree of integration with regional and international equity markets to be time-varying. We find that TSE returns are CAPM-efficient at monthly frequency. More-over, we find evidence in support of international integration of the TSE. We conduct event studies for TSE returns to examine the impact of non-market events. We find that TSE returns have become less sensitive to non-market factors over time., and seminar participants at 2010 Conference on Iran's Economy for their help and comments, which improved this paper. Golaleh Moshrefi provided research assistance. The remaining errors are ours.
Http Dx Doi Org 10 1080 00036840600707274, Apr 11, 2011
This paper address the extent of capital mobility and foreign debt sustainability in Turkey over ... more This paper address the extent of capital mobility and foreign debt sustainability in Turkey over the 1962–2003 period by examining the relationship between saving and investment, and imports and exports, respectively. The empirical investment is based on cointegration, error correction models, and threshold and momentum threshold autoregressive models. Our findings are consistent with the existence of capital mobility and the
Journal of Clinical Neuroscience, 2016
Endoscopic third ventriculostomy (ETV) is an alternative to ventriculoperitoneal shunting for tre... more Endoscopic third ventriculostomy (ETV) is an alternative to ventriculoperitoneal shunting for treatment of hydrocephalus. Studies have reported favorable outcomes for up to three-quarters of adult patients. We performed the first ETV outcomes study using an administrative claims database, examining current practice for adult patients in the United States. We interrogated the Truven Health MarketScan® database for Current Procedural Terminology codes corresponding to ETV and ventriculoperitoneal shunt from 2003- to 2011, including patients over 18years and data from initial and subsequent hospitalizations. ETV failure was defined as any subsequent ETV or shunt procedure. Five hundred twenty-five patients underwent ETV with 6months minimum follow-up. Mean age was 45.9years (range: 18-86years). Mean follow-up was 2.2years (SD: 1.6years, range: 0.5-8.4years). Etiology of hydrocephalus was 21.3% tumor, 9.0% congenital/aqueductal stenosis, 15.8% hemorrhage, and 53.9% others. ETV was successful in 74.7% of patients. Of 133 who failed, 25 had repeat ETV; 108 had shunt placement. Longer length of stay for index surgery was associated with higher risk of failure (hazard ratio (HR): 1.03, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001), as was history of previous shunt (HR: 2.45, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Among patients with repeat surgeries, median time to failure was 25days. This study represents a longitudinal analysis of nationwide ETV practice over 9years. Success rate in this large cohort is similar to that published by other single-center retrospective studies. Age and geographic variation may be associated with surgeon choice of ETV or shunt placement after failure of the initial ETV.
Journal of Research in Medical Sciences, Jan 4, 2014
Asian Spine Journal, 2016
Cross-sectional. To translate and culturally adapt an Iranian version of the Pain Sensitivity Que... more Cross-sectional. To translate and culturally adapt an Iranian version of the Pain Sensitivity Questionnaire (PSQ) in Iran. Instruments measuring patient reported outcomes should satisfy certain psychometric properties. 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. The mean age of participants was 51.7 years. Reliability, validity and correlation of PSQ and PCS showed satisfactory results. Cronbach&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;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. The adapted Iranian PSQ is a valid and reliable questionnaire for the assessment of pain in patients with LDH.
Asian Spine Journal, 2016
Cross-sectional. Clinical outcome study comparing the Copenhagen Neck Functional Disability Scale... more Cross-sectional. Clinical outcome study comparing the Copenhagen Neck Functional Disability Scale (CNFDS) and modified Japanese orthopedic association (mJOA) assessment scales in patients with cervical spondylotic myelopathy (CSM). Comparison of instruments that measure patient-reported outcomes is needed. A cross-sectional analysis was conducted. Ninety five patients with CSM were entered into the study and completed the CNFDS and the mJOA preoperatively and postoperatively. Correlation between the CNFDS and the mJOA was evaluated preoperatively and at the end of follow-up. Responsiveness to change of CNFDS and mJOA was also assessed. Clinical outcomes were also measured with the recovery rate of mJOA score at end of follow-up. The mean age of patients was 58.2 (standard deviation, SD=8.7) years. Mean follow-up was 2.1 years (range, 1 to 4 years). The mJOA correlated strongly with the CNFDS score preoperatively and postoperatively (r=-0.81 and -0.82, respectively; p&amp;amp;amp;amp;amp;amp;amp;lt;0.001). The CNFDS and the mJOA were able to detect changes after the surgery (p&amp;amp;amp;amp;amp;amp;amp;lt;0.001). The mean mJOA recovery rate was 51.8% (SD=13.1%). Surgery for the treatment of patients with CSM is an efficacious procedure. CNFDS and mJOA scores have a strong correlation in measuring disability among CSM patients.
PLOS ONE, 2016
The aim of the study was to compare outcome of surgery in patients with lumbar canal stenosis (LC... more The aim of the study was to compare outcome of surgery in patients with lumbar canal stenosis (LCS) based on magnetic resonance imaging (MRI) morphology. This was a prospective study of 96 consecutive patients who underwent surgery at 143 levels of LCS (from L3-L4 to L5-S1). Using patterns on T2 axial MRI, the type of stenosis was determined for each patient. The Swiss Spinal Stenosis Score (SSS) was used to evaluate patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; functionality and outcomes. The definition of treatment success was based on the criteria developed by Stucki et al. Demographic characteristics and post-operative outcomes were compared between trefoil, triangular, and pin-hole groups. Finally, correlation between SSS score and the MRI morphology was assessed. The mean age of patients was 58.4 (SD = 8.9) years. Post-treatment satisfaction was observed in a large portion of the patients (87.5%). The trefoil group (n = 44), triangular group (n = 38), and pin-hole group (n = 14) had similar pre-operative Swiss Spinal Stenosis Score and were not significantly different in age, operative time, blood loss, duration of symptoms, walking distance, symptom severity and physical function (all p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.4). No correlation between SSS score and the MRI morphology was observed. The findings suggest that the type of stenosis based on magnetic resonance imaging morphology is not indicative of surgical outcome among lumbar canal stenosis patients who undergo surgery at 1-year follow-up.
Asian Spine Journal, 2016
Cross-sectional. To develop a strategy to determine a sound method for decision-making based on p... more Cross-sectional. To develop a strategy to determine a sound method for decision-making based on postoperative clinical outcome satisfaction. The ideal management of thoracolumbar and lumbar burst fractures (TLBF) without neurological compromise remains controversial. This was a prospective study. Patients with thoracolumbar injury severity and classification score (TLICS) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;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. In all 113 patients with T11-L5, TLBFs were treated. The patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). According to the findings, a decision matrix was proposed. The findings confirm that TLICS &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;4, age, and residual canal can be used to guide the treatment of TLBF in conservative decision-making.
Asian spine journal, 2015
Cross-sectional. To translate and validate the Iranian version of the Copenhagen Neck Functional ... more Cross-sectional. To translate and validate the Iranian version of the Copenhagen Neck Functional Disability Scale (CNFDS). Instruments measuring patient-reported outcomes should satisfy certain psychometric properties. 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. 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....
Asian Spine Journal, 2015
Case-control design. To evaluate the role of the self-administered, self-reported history questio... more Case-control design. To evaluate the role of the self-administered, self-reported history questionnaire (SSHQ) in identifying types of lumbar spinal stenosis (LSS). Diagnosis of types of LSS is controversial. 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. 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. 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.
Background and Purpose: Decision-making process in Thoracolumbar and Lumbar Burst Fracture (TLBF)... more Background and Purpose: Decision-making process in Thoracolumbar and Lumbar Burst Fracture (TLBF) patients with Thoracolumbar Injury Severity and Classification Score (TLICS) > 4 is remained controversial. On the other hand, the question is whether that the Oswestry Disability Index (ODI) can be use to assess to clinical outcomes in these patients. We aimed to study the correlation between the ODI and American Spinal Injury Association (ASIA) impairment scale in these patients and evaluation of surgical outcome. Methods: This was a prospective study. The TLICS were determined and TLICS > 4 was included. The nerve injury was assessed according to sensory scores and motors scores of the using ASIA Scale at pre- and postoperative. It was also ODI calculated at last follow-up. In addition, correlation between ASIA and ODI was evaluated at last follow-up. Results: Fifty eight patients (20.7% female) who underwent spinal surgery for TLBF with a minimum follow up of 2 years were stud...
Asian Spine Journal, 2015
Case-control study. To design a new tool for classifying lumbar spinal canal stenosis (CLSCS). Gr... more Case-control study. To design a new tool for classifying lumbar spinal canal stenosis (CLSCS). Grading of patients with lumbar spinal canal stenosis (LSCS) is controversial. 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. 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;7 (grade 0); 7≤CLSCS&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10 (grade 1); 10≤CLSCS&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;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. The CLSCS score can be helpful for classifying LSCS patients and in the decision-making process.
Journal of neurosurgical sciences, Jan 11, 2014
A lack of consensus exists regarding indications for surgery for lumbar spinal canal stenosis (LS... more A lack of consensus exists regarding indications for surgery for lumbar spinal canal stenosis (LSCS). Hence, the aim of this study is to develop an artificial neural network (ANN) model that is designed to accurately select patients for surgery or non--surgical options and to compare such with the traditional clinical decision making approach in LSCS patients. An ANN model and a logistic regression (LR) model were used as predicting models. The data for a total of 346 of 379 patients (143 male, 203 female, mean age 59.5±11.5 years) were available for the analysis. The measured metrics included visual analog scale (VAS) of leg pain/numbness, the Japanese Orthopaedic Association (JOA) Score, the Neurogenic Claudication Outcome Score (NCOS), the Oswestry disability index (ODI), the Swiss Spinal Stenosis Score (SSS), the stenosis bothersomeness index (SBI), the dural sac cross--sectional surface area (DSCA), the Stenosis Ratio (SR), the Self--Paced Walking Test (SPWT), morphology grade ...
Journal of neurosurgical sciences, 2014
A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score ... more A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score (SSS) is a well-known questionnaire that measures the severity of symptoms, physical functioning and patient's satisfaction in lumbar spinal stenosis. This study aimed to translate and validate the SSS in Iran. A prospective clinical validation study was performed. Forward-backward procedure was applied to translate the original questionnaires into Persian. A sample of patients with lumbar spinal stenosis completed the questionnaire twice: at pre- and postoperative (6 months follow-up) assessments. To test reliability the internal consistency was assessed by the Cronbach's alpha coefficient. Validity was evaluated using the known groups comparison. In addition the Oswestry Disability Index was used to perform convergent validity. In all 121 patients were entered into the study. The mean age of patients was 62.3 (SD=10.2) years. The Cronbach's alpha coefficient for the SSS was...
Purpose: This study aimed to correlation between the grading stenosis and the STarT Back Screenin... more Purpose: This study aimed to correlation between the grading stenosis and the STarT Back Screening Tool (SBST) in patients diagnosed with lumbar central canal stenosis (LCCS). Methods: In a prospective clinical study, a total of 269 patients with LCCS were asked to respond to the questionnaire at their first visits. Grading of LCCS on MRI was determined and also the severities of the disease were observed based on SBST as the gold standard. Finally grading on MRI and calcification of the SBST were determined, and sensitivity analysis carried out to evaluate severity of LCCS on grading of MRI using the SBST. Results: The mean age of patients was 58.6 (SD= 10.9) years; and 56.5% were female. According to patients’ imaging they have been diagnosed as grade 1 (n = 86), grade 2 (n = 107) and grade 3 (n = 76). The sensitivity, specificity and accuracy of the estimated grading of LCCS on MRI for low, medium, and high risk groups were found to be desirable: 97.6%, 66.7%, 96.5% for low risk;...
Purpose: This study investigated functionality statues and surgical outcome of patients with cerv... more Purpose: This study investigated functionality statues and surgical outcome of patients with cervical spondylotic myelopathy (CSM) contains cervical herniated disc (CHD) and cervical spinal stenosis (CSS) based on the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). Methods: This was a prospective clinical study a sample of cases with CSM. Patient’s functionality statues and surgical outcome were evaluated based on JOACMEQ scores at two points in time: pre- and postoperative assessments. Results: In all 87 patients were completed the JOACMEQ measure. The mean age of patients was 50.3 (SD=10.2) years. The mean clinical follow-up was 12 months (range 7-37 months). Statistically difference between was observed pre- and postoperative indicating improvements on the outcomes and functionality in all subscales (P < 0.001). However, there was no significant difference between patients with CSM and CHD. Conclusion: The findings suggest that surgery i...
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, 2012
Lumbar disc hernia (LDH) is a common cause of low back pain and radicular leg pain. The Japanese ... more Lumbar disc hernia (LDH) is a common cause of low back pain and radicular leg pain. The Japanese Orthopedic Association (JOA) score is a very short instrument for measuring functionality and pain in these patients. This study aimed to translate and validate the JOA score for use in Iran. This was a prospective clinical validation study. Translation of the English version of the questionnaire was performed in accordance with published guidelines. A sample of patients with LDH was asked to respond to the questionnaire at two points in time--at preoperative and postoperative (6 months follow-up) assessments. To test reliability, the internal consistency was assessed by use of Cronbach's alpha coefficient. Validity was evaluated by use of known-groups comparison. A total of 117 patients with LDH were entered into the study. The mean age of patients was 45 (SD = 11) and Cronbach's alpha coefficients for the JOA score at the preoperative and postoperative assessments were 0.67 and...
Materia Socio Medica, 2014
Introduction: For almost fifteen years, the application of computer in hospitals increasingly has... more Introduction: For almost fifteen years, the application of computer in hospitals increasingly has become popular. Nurses' beliefs and attitudes towards computer is one of the most important indicators of the application of nursing information system. The purpose of this study was to investigate the perceptions of nurses on the usefulness of nursing information system for patient care. Methods: Here, a descriptive study was carried out. Sample was consisted of 316 nurses working in teaching hospitals in an urban area of Iran. This study was conducted during 2011 to 2012. A reliable and valid questionnaire was developed as a data collection tool. The collected data was analyzed using descriptive and inferential statistics. Results: It was not believed that nursing information system was useful for patient care. However, it was mentioned that nursing information system is useful in some aspects of patient care such as expediting care, making early diagnosis and formulating diet plan. A significant association was found between the demographic background of sample and their perceptions of the usefulness of nursing information system (P<0.05). Conclusion: Totally, it can be concluded that nursing information system has a potential for improving patient care in hospital settings. Therefore, policy makers should consider implementing nursing information system in teaching hospitals.
2008 International Conference on Microelectronics, 2008
The increasing rate of transient faults necessitates the use of on-chip fault-tolerant techniques... more The increasing rate of transient faults necessitates the use of on-chip fault-tolerant techniques in embedded microprocessors. Performance overhead is a challenging problem in on-chip fault-tolerant techniques used in the random logic of the embedded microprocessors. This paper presents a signaturebased error detection and roll-back recovery technique for the control logic with much lower performance overhead as compared to many previous techniques. The low performance overhead is achieved by eliminating the fault masking overhead cycles in the previous techniques. The performance overhead is analytically studied, and the analytical results recommend at which fault rate the use of the technique is preferred. To measure the cycle time of the pipeline critical path and area overhead, this technique has been implemented and synthesized using a behavioral VHDL model of the Leon2 processor. The synthesis results show that the area and the cycle time overhads of the technique are only 17.7% and 3.4%, respectively. In addition, the injection of about 74000 transient single bit-flip faults into the control logic part of the Leon2 processor shows that the technique detected about 99% of the injected faults.
Journal of Spinal Disorders and Techniques, 2014
The aim of this study was to develop an artificial neural network (ANN) model to predict recurren... more The aim of this study was to develop an artificial neural network (ANN) model to predict recurrent lumbar disk herniation (LDH). An ANN model and a logistic regression model were used to predict recurrent LDH. The age, sex, duration of symptoms, smoking status, recurrent LDH, level of herniation, type of herniation, sports activity; occupational lifting, occupational driving, duration of symptoms, visual analog scale (VAS), the Zung Depression Scale (ZDS), and the Japanese Orthopaedic Association (JOA) Score, were determined as the input variables for the established ANN model. The Macnab classification, VAS, and JOA were used for outcome assessment. ANNs on data from LDH patients, who underwent surgery, were trained to predict LDH using several input variables. The patients were divided into a recurrent LDH group (R group) and a primary LDH group (P group). Sensitivity analysis was applied to identify the relevant variables. The receiver-operating characteristic curve, accuracy rate of predicting, and Hosmer-Lemeshow statistics were considered for evaluating the 2 models. A total of 402 patients were categorized into training, testing, and validation data sets consisting of 201, 101, and 100 cases, respectively. The recurrence rate was 8.7%, and the median time to recurrence was 26.2 months (SD=4 mo). The VAS of leg/back pain and JOA were improved at 1-year follow-up (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and no significant difference was observed between the 2 groups. Surgical successful outcome was categorized as: excellent, 31.1%; good, 44.3%; fair, 18.9%; and poor, 5.7% at 1-year follow-up. Compared with the logistic regression model, the ANN model was associated with superior results: accuracy rate, 94.1%; Hosmer-Lemeshow statistic, 40.2%; and area under the curve, 0.83% of patients. The findings show that an ANNs can be used to predict the diagnostic statues of recurrent and nonrecurrent group of LDH patients before the first or index microdiscectomy.
SSRN Electronic Journal, 2000
ABSTRACT This paper analyzes market index returns in the Tehran stock exchange (TSE) within the c... more ABSTRACT This paper analyzes market index returns in the Tehran stock exchange (TSE) within the context of three variants of the Capital Asset Pricing Model: the static international; the constant-parameter intertemporal; and a Markov-switching intertemporal CAPM, which allows for the degree of integration with regional and international equity markets to be time-varying. We find that TSE returns are CAPM-efficient at monthly frequency. More-over, we find evidence in support of international integration of the TSE. We conduct event studies for TSE returns to examine the impact of non-market events. We find that TSE returns have become less sensitive to non-market factors over time., and seminar participants at 2010 Conference on Iran's Economy for their help and comments, which improved this paper. Golaleh Moshrefi provided research assistance. The remaining errors are ours.