Cost-effectiveness of fusion with and without instrumentation for patients with degenerative spondylolisthesis and spinal stenosis

Study Design. A cost-effectiveness study was performed from the societal perspective. Objective. To evaluate the costs and benefits of laminectomy alone and laminectomy with concomitant lumbar fusion for patients with degenerative lumbar spondylolisthesis and spinal stenosis. Summary of Background Data. Costs, probabilities, and utilities were estimated from the literature. Short-term risks considered were perioperative complications, the probability of the fusion healing, and, the probability that surgery will relieve symptoms. Long-term risks considered were recurrence of symptoms and reoperation. Methods. The 10-year costs, quality-adjusted life years, and incremental cost-effectiveness ratios (reported as dollars per quality- adjusted year of life gained) were calculated using a Markov model. Sensitivity analysis was performed on all variables using clinically plausible ranges. Results. Laminectomy with noninstrumented fusion costs $56,500 per quality-adjusted year of life versus laminectomy without fusion. The cost-effectiveness of laminectomy with noninstrumented fusion was most sensitive to the increase in quality-of-life associated with relief of severe stenosis symptoms. The cost-effectiveness ratio of instrumented fusion compared with noninstrumented fusion was $3,112,800 per quality-adjusted year of life. However, if the proportion of patients experiencing symptom relief after instrumented fusion was 90% as compared with 80% for patients with noninstrumented fusion, then the cost-effectiveness ratio of instrumented fusion compared with noninstrumented fusion would be $82,400 per quality- adjusted year of life. Conclusions. The cost-effectiveness of laminectomy with noninstrumented fusion compares favorably with other surgical interventions, a though it depends greatly on the true effectiveness of these surgeries to alleviate symptoms and on how patients value the quality-of-life effect of relieving severe stenosis symptoms. Instrumented fusion was very expensive compared with the incremental gain in heath outcome. Better data on the effectiveness of these alternative procedures are needed.