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

Study Design. A cost-effectiveness study was per: formed from the societal perspective. Objective. To evaluate the costs and benefits of laminectomy alone and lami nectomy with concomitant lumbar fusion for patients with degenerative lumba r spondylolisthesis and spinal stenosis. Summary of Background Data. Costs, probabilities, and utilities were estima ted from the literature. Short term risks considered were perioperative com plications, 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 co st-effectiveness ratios (reported as dollars per quality-adjusted year of l ife 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-effective ness of laminectomy with noninstrumented fusion was most sensitive to the i ncrease in quality-of-life associated with relief of severe stenosis sympto ms. The cost-effectiveness ratio of instrumented fusion compared with nonin strumented fusion was $3,112,800 per quality-adjusted year of life. However , if the proportion of patients experiencing symptom relief after instrumen ted fusion was 90% as compared with 80% for patients with noninstrumented f usion, then the cost-effectiveness ratio of instrumented fusion compared wi th noninstrumented fusion would be $82,400 per quality-adjusted year of lif e. Conclusions. The cost-effectiveness of laminectomy with noninstrumented fus ion compares favorably with other surgical interventions, although it depen ds greatly on the true effectiveness of these surgeries to alleviate,-sympt oms and on how patients value the quality-of-tife effect of relieving sever e stenosis symptoms. Instrumented fusion was very expensive compared with t he incremental gain in health outcome. Better data on the effectiveness of these alternative procedures are needed.