Surgical treatment for adult spinal deformity: Projected cost effectiveness at 5-year follow-up

Background: In the United States, expenditures related to spine care are estimated to account for $86 billion annually. Policy makers have set a cost-effectiveness benchmark of less than $100,000/quality adjusted life year (QALY), forcing surgeons to defend their choices economically. This study projects the cost/QALY for surgical treatment of adult spinal deformity at 5-year follow-up based on 2-year cost- and health-related quality-of-life (HRQOL) data. Methods: In a review of 541 patients with adult spinal deformity, the patients who underwent revision or were likely to undergo revision were identified and cost of surgery was doubled to account for the second procedure; all other patients maintained the cost of the initial surgery. Oswestry Disability Index (ODI) was modeled by revision status based on literature findings. Total surgical cost was based on Medicare reimbursement. Chi square and student t tests were utilized to compare cost-effective and non-cost-effective patients. Results: The average cost/QALY at 5-year follow-up was $120,311.73. A total of 40.7% of patients fell under the threshold of a cost/QALY <$100,000. Cost-effective patients had higher baseline ODI scores (45% vs 34% [P=0.001]), lower baseline total Scoliosis Research Society scores (2.89 vs 3.00 [P=0.04]), and shorter fusions (8.23 vs 9.87 [P=0.0001]). Conclusion: We found 40.7% of patients to be below the threshold of cost effectiveness. Factors associated with reaching the threshold <$100,000/QALY were greater preoperative disability, diagnosis of idiopathic scoliosis, poor preoperative HRQOL scores, and fewer fusion levels.