Reoperation rate after surgery for lumbar spinal stenosis without spondylolisthesis: a nationwide cohort study.

BACKGROUND CONTEXT Lumbar spinal stenosis is one of the most common degenerative spine diseases. Surgical options are largely divided into decompression only and decompression with arthrodesis. Recent randomized trials showed that surgery was more effective than nonoperative treatment for carefully selected patients with lumbar stenosis. However, some patients require reoperation because of complications, failure of bony fusion, persistent pain, or progressive degenerative changes, such as adjacent segment disease. In a previous population-based study, the 10-year reoperation rate was 17%, and fusion surgery was performed in 10% of patients. Recently, the lumbar fusion surgery rate has doubled, and a substantial portion of the reoperations are associated with a fusion procedure. With the change in surgical trends, the longitudinal surgical outcomes of these trends need to be reevaluated. PURPOSE To provide the longitudinal reoperation rate after surgery for spinal stenosis and to compare the reoperation rates between decompression and fusion surgeries. STUDY DESIGN/SETTING Retrospective cohort study using national health insurance data. PATIENT SAMPLE A cohort of patients who underwent initial surgery for lumbar stenosis without spondylolisthesis in 2003. OUTCOME MEASURES The primary end point was any type of second lumbar surgery. Cox proportional hazards regression modeling was used to compare the adjusted reoperation rates between decompression and fusion surgeries. METHODS A national health insurance database was used to identify a cohort of patients who underwent an initial surgery for lumbar stenosis without spondylolisthesis in 2003; a total of 11,027 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. After adjusting for confounding factors, the reoperation rates for decompression and fusion surgery were compared. RESULTS Fusion surgery was performed in 20% of patients. The cumulative reoperation rate was 4.7% at 3 months, 7.2% at 1 year, 9.4% at 2 years, 11.2% at 3 years, 12.5% at 4 years, and 14.2% at 5 years. The adjusted reoperation rate was not different between decompression and fusion surgeries (p=.82). The calculated reoperation rate was expected to be 22.9% at 10 years. CONCLUSIONS The reoperation rate was not different between decompression and fusion surgeries. With current surgical trends, the reoperation rate appeared to be higher than in the past, and consideration of this problem is required.