Severity of symptoms, physical functioning and satisfaction in patients with lumbar spinal stenosis: a validation study of the Iranian version of the Swiss Spinal Stenosis Score (SSS)

Abstract

Background and Objective: A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score (SSS) is a well-known questionnaire measuring the severity of symptoms, physical functioning and patient’s satisfaction in these patients. This study aimed to translate and validate the SSS in Iran.Methods: This was a prospective clinical validation study. Forward-backward procedure was applied to translate the original questionnaires into Persian. A sample of patients with lumbar spinal stenosis completed the questionnaire twice: pre- and post-operative (6-month follow-up) assessments. To test reliability the internal consistency was assessed; Validity was evaluated using known groups comparison. In addition Oswestry Disability Index was used to perform convergent validity.Results: In all 121 patients were entered into the study. The mean age of patients was 62.3 (SD = 10.2) years. Cronbach’s alpha coefficient for the SSS was found to be 0.88. Validity assessment was performed using common group’s analysis and showed satisfactory results. The instrument discriminated efficiently between sub-groups of patients who differed in age, severity of lumbar spinal stenosis, and Self-Paced Walking Test (SPWT). The change in Oswestry Disability Index strongly correlated with the change in patients’ scores on the SSS, lending support to its good convergent validity (r = 0.82; P < 0.001).Conclusion: The Iranian version of the Swiss Spinal Stenosis Score performed well and the findings suggest that it is a valid measure of the severity of symptoms, physical function and satisfaction among lumbar spinal stenosis patients.