Abstract
INTRODUCTION While the expansion of health insurance coverage and access to care has led to substantial increase in national rates and costs of spinal surgery, there is significant variation across states. We aimed to analyze the utilization and costs in Arizona, and to identify factors that underlie this variation. METHODS We collected patient demographic, clinical, and charge data for all 145 139 spine procedures performed in Arizona 2005-2016 from the Intellimed Inpatient Database. Hospital costs were calculated using hospital-specific charge-to-cost ratios from the Arizona Department of Health Services. RESULTS The overall spine surgery rates in Arizona increased steadily between 2005 (1.43 per 1000 adults; n = 8341) and 2016 (1.66 per 1000 adults; n = 11,541). In 2016, posterior lumbar fusion (n = 5078) and anterior cervical discectomy and fusion (n = 2869) were the most frequently performed procedures and saw the greatest increases in utilization rate since 2005, 27.9 and 11.1 per 100 000 patients, respectively. Average hospital costs rose substantially from $19 022 to $37 596. We observed significant interhospital variation, with costs for a single-level posterior lumbar spine fusion with minor SOI and 1 d length of stay (LOS) ranging between $7068 and $55 625. Multivariate analyses showed that age, race, insurance status, surgical specialty, SOI, and nonelective admission were associated with higher costs (P < .001). Of the 34 hospitals included, 62% had higher charges for the neurosurgery service. Patients who underwent spine surgery by neurosurgeons had higher SOI (2.4 vs 1.6) and longer average LOS (7.51 vs 3.21 d) than orthopedic surgeons. After adjusting for differences in SOI, LOS, and case mix, we found that orthopedists had higher costs than neurosurgeons ($26 194 vs $24 255). CONCLUSION Utilization and costs of spine surgery in Arizona has increased significantly. Understanding regional costs and variations can help guide policy decisions such as bundled payment programs from the Centers of Medicare and Medicaid Services and deliver cost-effective care.