Predictors of cost for posterior spinal fusion in adolescent idiopathic scoliosis

Study design: Single-center retrospective review of pediatric patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis (AIS). Objective: To determine what clinical and operative factors influence inflation-adjusted hospital costs of posterior spine fusion surgery for AIS. Summary of background data: With rising healthcare costs and the advent of bundled payments, it is essential understand the predictors of costs for surgical procedures. We sought to determine the components of hospital costs for AIS posterior spine fusion surgery using standardized, inflation-adjusted, line-item costs for services and procedures. Methods: The study population comprised 148 AIS patients who underwent spinal fusion surgery at a large tertiary care center between 2009 and 2016. Data on medical characteristics, curve type, curve magnitude, number of screws and the number of levels was collected through manual chart review of X-rays and medical records. Hospital costs from admission until discharge were retrieved from an institutional database that contained line-item details of all procedures and services billed during the hospital episode. Bottom-up microcosting valuation techniques were used to generate standardized inflation-adjusted estimates of costs and standard deviations in 2016 dollars. Results: Mean cost of AIS surgery was $48,058 ± 9379. Physician fees averaged 15% of the total cost ($7045 ± 1732). Implant costs and surgical/anesthesia/surgeon’s fees accounted for over 70% of the hospital costs. Mean number of screws was 16 ± 4.5, mean number of levels fused was 11.2 ± 2.2, and the mean implant density (screws per level fused) was 1.45 ± 0.35. On multivariate analysis, the number of screws per level fused, number of levels fused, curve magnitude and length of stay were all significantly associated with hospital costs (p < 0.01). Conclusions: Bundled payments for AIS surgery should include adjustments for number of levels fused and curve size. Areas for cost savings include further reduction in implant costs, shortening length of stay, and reducing intraoperative costs. Level of evidence: III.