Development and validation of a symptom scale for lumbar spinal stenosis.

Abstract

A cross-sectional study. We developed a reliable and valid instrument to measure symptom severity in patients with lumbar spinal stenosis (LSS). Studies on LSS have investigated the efficacy of drug therapy compared with conservative therapy and surgery, examined predictive factors for therapeutic effects, and ascertained postoperative quality of life. However, patient background factors have varied among studies, making it difficult to compare findings across studies. First, focus group interviews were conducted, and data were analyzed using qualitative methods. Then, 189 patients with a diagnosis of LSS from 9 hospitals completed the LSS questionnaire. Exploratory factor analysis was conducted to examine the construct validity, and Cronbach α coefficient was calculated to test internal consistency. The criterion-related validity used pain, numbness, and walking capacity as external criteria. The test-retest reliability with an interval of 1 to 5 weeks was analyzed in 163 patients. Qualitative study extracted 10 domains and created a pool of 36 items. With factor analysis, items with factor loading less than 0.35 were excluded, and 25 items in 8 domains were selected. The Cronbach α of these items was 0.929. The coefficient of the test-retest reliability was 0.807. Pain, numbness, and walking capacity were significantly correlated with the scores of the LSS symptom scale. A 25-item LSS symptom scale was developed, and its reliability and validity were confirmed.