Patient satisfaction as an outcome measure after surgical treatment for lumbar spinal stenosis: testing the validity and discriminative ability in terms of symptoms and functional status.

Abstract

A prospective observational study of 204 patients treated surgically for lumbar spinal stenosis. To validate a measure of patient satisfaction with outcome in terms of symptoms and functional status, investigate the association of satisfaction with treatment effect, and estimate the discriminative ability. The properties of global measures of patient satisfaction with outcome are unknown. Patients completed preoperative and follow-up questionnaires about symptom severity, walking ability, functional status, and their overall satisfaction with the surgical results. The patients were asked a single-item question rating their satisfaction. Correlations between satisfaction and symptom severity, walking ability, and function measured by back-specific questionnaires were calculated. The associations of satisfaction with the postoperative score and the score change for each outcome measure were determined, and the discriminative ability was evaluated by the receiver-operating characteristic method. The correlations with the postoperative scores were significant. Satisfaction was much more strongly associated with postoperative scores than with score changes. However, patient satisfaction did not correctly discriminate between improved and nonimproved patients. The single-item global measure of satisfaction with outcome was valid, but it did not reflect the treatment effect and did not correctly distinguish between clinically important changes.