Cost per quality-adjusted life year gained of revision fusion for lumbar pseudoarthrosis

Study Design: Single cohort study of patients undergoing revision fusion for lumbar pseudoarthrosis. Objective: To assess the 2-year comprehensive costs of revision arthrodesis for lumbar pseudoarthrosis at our institution and determine the associated cost per quality-adjusted life year (QALY) gained in this patient population. Summary of Background Data: The proportion of lumbar spine operations involving a fusion procedure has increased over the past 2 decades. Similarly, there has been a corresponding increase in the incidence and prevalence of pseudoarthrosis. However, the cost-effectiveness of revision surgery for pseudoarthrosis-associated back pain has yet to be examined. Methods: Forty-seven patients undergoing revision instrumented arthrodesis for pseudoarthrosis-associated back pain were included. Two-year total back-related medical resource utilization, missed work, and health-state values (QALYs, calculated from EuroQuol 5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost) and patient and care-giver work-day losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after revision surgery was assessed. Results: The mean (±SD) duration of time between prior fusion and development of symptomatic pseudoarthrosis was 2.69±3.09 years. None of the patients developed symptomatic pseudoarthrosis after 2 years of revision surgery. A mean cumulative 2-year gain of 0.35 QALYs was reported. The mean (±SD) total 2-year cost of revision fusion was 41,631±9691 (surgery cost: 23,865±270; outpatient resource utilization cost: 4885±2301; indirect cost: 12,879±8171). Revision instrumented arthrodesis was associated with a mean 2-year cost per QALY gained of 118,945. Conclusions: Revision arthrodesis was associated with improved 2-year quality of life in patients with pseudoarthrosis-related back pain. Nevertheless, in our experience revision surgery was shown to be marginally cost-effective at 118,945 per QALY gained.