Trends in Robot-Assisted Spinal Fusion Surgeries: An Analysis by Age Group, Race, ZIP Code Income Quartile, and Urban-Rural Classification
Connor Burke, Andrew Brumett, Matthew Blackwell, Arshjeet Singh, Anoop S. Chinthala, Raj Swaroop Lavadi, Gordon MaoStudy Design
Retrospective Serial Cross-Sectional Study.
Objectives
Robotic assistance in spinal fusion surgery has been associated with improved perioperative outcomes. Given the potential benefits and resource requirements of robotic platforms, it is important to identify adoption trends to inform efforts in surgical resource allocation. This study analyzes trends by age group, race, urban-rural location, primary payer, and ZIP-code income quartile among patients undergoing robot-assisted spinal fusion relative to concurrent trends in free-hand fusion.
Methods
A retrospective serial cross-sectional analysis was performed using the 2010-2021 National Inpatient Sample (NIS). This study analyzed 34,911 robot-assisted and 5.19 million free-hand spinal fusion cases. Survey-weighted Poisson regression estimated subgroup-specific prevalence ratios across sequential three-year eras, and difference-in-differences rate ratios compared changes in the robotic cohort with concurrent changes in the free-hand cohort. An ICD-10-era sensitivity analysis was performed.
Results
Compared with free-hand, robotic representation declined in central-metropolitan counties (DiD RR 0.55, 95% CI 0.46-0.66, p<0.0001) and increased in small-metropolitan counties (RR 2.81, 1.06-7.43, p=0.037) and among Medicaid-insured patients (RR 6.49, 1.02-41.50, p=0.048). Pediatric representation declined (RR 0.23, 0.13-0.42, p<0.0001). In ICD-10-era sensitivity analyses, the central-metropolitan decline and Medicaid finding persisted, whereas the small-metropolitan and pediatric findings were not reproduced.
Conclusions
Robot-assisted spinal fusion demonstrated geographic and payer-related shifts relative to free-hand fusion. Decreased representation in central-metropolitan counties was the most consistent finding. Medicaid representation increased among robotic cases relative to free-hand fusion, but this finding should be interpreted cautiously because the baseline Medicaid count in the robotic cohort was small.