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

Abstract

Background: The purpose of this study was validation of the Persian translation of the Swiss Spinal Stenosis<br />Questionnaire in order to be used by Iranian researchers.<br />Methods: A total of 104 patients with spinal stenosis diagnosis, who were candidates for operative treatment were<br />entered into the study. The patients completed the translated questionnaire in the 1st and the 7th days of admission<br />and 6 months after surgery. Visual analogue scale was used to determine the severity of the pain in the1st day and<br />the 6th month. Discriminant validity, convergent validity, test-retest reliability, internal consistency, ability to detect<br />changes and sensitivity to clinical changes were assessed for the statistical purposes.<br />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 and<br />total items, Cronbach's α was 0.942, 0.957, 0.926 and Intraclass correlation were 0.891, 0.918, 0.862, respectively. Paired<br />t-test was significantly different between the 1st day and the 6th month questionnaire. There was a positive correlation either<br />between the first VAS and the 1st day questionnaire (1st day Q) (r=0.892, P=0.000) or between the 6th month VAS and 6th<br />month Q (r=0.940, P=0.000). The Pearson's correlation between the difference of the total scores of the 1st day and the<br />6th month and satisfaction score after surgery showed negative correlation (r= -0.746, P=0.000). The effect size was 2.55.<br />Conclusion: The Iranian version of the Swiss Spinal Stenosis has excellent internal consistency, excellent reliability,<br />good ability to alter with changes, especially parallel with clinical improvement, excellent ability to detect changes, and<br />well either convergent or discriminant validity.