Do Demographic Factors of Spine Surgeons Affect the Rate at Which Spinal Fusion Is Performed on Patients?

STUDY DESIGN: Retrospective study.

OBJECTIVE: The purpose of this study was to evaluate associations between spine surgeon demographics and the rate at which elective spine fusion is performed.

SUMMARY OF BACKGROUND DATA: Rapidly increasing rates of elective spinal fusion in the United States have given rise to important questions about what factors may drive spine surgeon decision making.

METHODS: Publicly available spine surgeon practice pattern data from Centers for Medicare and Medicaid Services were reviewed retrospectively. Fusion rate was defined as the number of fusion procedures performed on Medicare beneficiaries by a surgeon per total number of unique Medicare beneficiaries seen. Inclusion criteria were neurological or orthopedic spine surgeons who performed 11 or more separate spine fusion procedures on Medicare patients between 2011 and 2013 as defined by this database. Demographic information was collected from public record. The increased probability of a surgeon performing spine fusion was assessed using a relative risk (RR) and corresponding 95% confidence interval (CI).

RESULTS: A total of 3979 spine surgeons who practice in the United States and performed spine fusion on 171,676 Medicare patients from 2011 to 2013 met the inclusion criteria. The average rate of spine fusion for surgeons in this database was 7.5%. Surgeons with higher fusion rates practiced in an academic versus private setting (RR = 1.44, 95% CI [1.35-1.53]; P < 0.0001), were more likely neurological versus orthopedic surgeons (RR = 1.10, 95% CI [1.05-1.15]; P < 0.0001), and practiced in the West versus Midwest, South, and Northeast region of the United States (RR = 1.20, 95% CI [1.14-1.27]; P < 0.0001). Number of years in practice was significantly associated negatively with fusion rate (P < 0.0001).

CONCLUSION: Significant variation in the rate of spine fusion based on practice type, training, region, and experience suggests poor consensus on indications for this procedure. Knowledge of these relationships may help identify underlying reasons for variations in surgical care and improve surgical outcomes.

LEVEL OF EVIDENCE: 3.