Reliability and Validity of the Swiss Spinal Stenosis Questionnaire for Iranian Patients with Lumbar Spinal Stenosis

Background: The purpose of this study was validation of the Persian translation of the Swiss Spinal StenosisQuestionnaire in order to be used by Iranian researchers.Methods: A total of 104 patients with spinal stenosis diagnosis, who were candidates for operative treatment wereentered into the study. The patients completed the translated questionnaire in the 1st and the 7th days of admissionand 6 months after surgery. Visual analogue scale was used to determine the severity of the pain in the1st day andthe 6th month. Discriminant validity, convergent validity, test-retest reliability, internal consistency, ability to detectchanges and sensitivity to clinical changes were assessed for the statistical purposes.Results: Cronbach’s α was more than 0.9 for all the items. ICC was about 0.9 for all the items. For symptoms, physical andtotal items, Cronbach’s α was 0.942, 0.957, 0.926 and Intraclass correlation were 0.891, 0.918, 0.862, respectively. Pairedt-test was significantly different between the 1st day and the 6th month questionnaire. There was a positive correlation eitherbetween the first VAS and the 1st day questionnaire (1st day Q) (r=0.892, P=0.000) or between the 6th month VAS and 6thmonth Q (r=0.940, P=0.000). The Pearson’s correlation between the difference of the total scores of the 1st day and the6th month and satisfaction score after surgery showed negative correlation (r= -0.746, P=0.000). The effect size was 2.55.Conclusion: The Iranian version of the Swiss Spinal Stenosis has excellent internal consistency, excellent reliability,good ability to alter with changes, especially parallel with clinical improvement, excellent ability to detect changes, andwell either convergent or discriminant validity.