Development and validation of a quality of life scale specific for lumbar spinal stenosis.

STUDY DESIGN: A cross-sectional study.

OBJECTIVE: To develop a reliable and valid instrument to measure quality of life (QOL) specifically targeting patients with lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA: Studies on LSS have investigated the effectiveness of various types of treatments using health-related QOL. However, patients with LSS have various symptoms, and these symptoms change with posture, typical activities of daily living, etc. Thus, an LSS-specific scale to measure QOL is needed.

METHODS: We postulated 7 subdomains for LSS-specific QOL and accordingly, item pool was developed, focus group interviews of patients with LSS and qualitative analysis were conducted, resulting in preliminary version of QOL scale. Then, 189 patients with a diagnosis of LSS completed this preliminary version. Exploratory factor analysis was conducted to examine the factorial validity. Cronbach alpha coefficient and the test-retest method were used to assess the reliability. The criterion-based validity was determined using walking capacity, recommended treatment level judged by orthopedists, and LSS symptom scale scores.

RESULTS: Qualitative study confirmed the 7 domains but showed needs of addition and deletion of some items, resulting in 31 items. With factor analysis, after exclusion of 3 items, the remaining 28 items demonstrated strong unidimensionality. Cronbach alpha was 0.96. The coefficient of test-retest reliability was 0.86. Walking capacity, recommended treatment level, and LSS symptom scale scores were significantly correlated with the QOL scale scores.

CONCLUSION: A 28-item QOL scale specifically targeting patients with LSS was developed, and its reliability and validity were confirmed.