Abstract
In order to satisfy the need of a tool for assessing the treatment of patients with degenerative lumbar spinal stenosis, an evaluation was made of the reliability, construct validity, and responsiveness of the Norwegian version of Spinal Stenosis Measure (SSM, original by Stucki)). This study was a part of a prospective, cohort study. About 75 patients referred for surgery for spinal stenosis participated in the study. A subsample of 30 patients answered the questionnaire twice, test and retest, with at least one week in between. The SSM was translated according to the Guillemin criteria. Reliability was assessed by Bland and Altman's repeatability, intraclass correlation coefficient (ICC) and the coefficient of variance (CV). Internal consistency was assessed by Cronbach's alpha. Construct validity was analysed by correlation analyses. Responsiveness was calculated by the effect size. The reliability between test and retest scores was good for all three subscales of SSM as the ICC-values were above 0.9 and the CVs were below 15%. Cronbach's alpha was above 0.8. The correlation analyses showed high correlation between scales that assessed the same construct, and low to moderate correlation between scales that assessed different constructs. Large effect sizes were found in all the SSM subscales with effect sizes > or =1.2. The Norwegian SSM version has added a highly useful tool for assessing the disease specific status and outcome after treatment in patients who suffer from degenerative lumbar spinal stenosis.