Hospital and surgeon variation in complications and repeat surgery following incident lumbar fusion for common degenerative diagnoses

Abstract

Objective: To identify factors that account for variation in complication rates across hospitals and surgeons performing lumbar spinal fusion surgery.

Data sources: Discharge registry including all nonfederal hospitals in Washington State from 2004 to 2007.

Study design: We identified adults (n = 6,091) undergoing an initial inpatient lumbar fusion for degenerative conditions. We identified whether each patient had a subsequent complication within 90 days. Logistic regression models with hospital and surgeon random effects were used to examine complications, controlling for patient characteristics and comorbidity.

Principal findings: Complications within 90 days of a fusion occurred in 4.8 percent of patients, and 2.2 percent had a reoperation. Hospital effects accounted for 8.8 percent of the total variability, and surgeon effects account for 14.4 percent. Surgeon factors account for 54.5 percent of the variation in hospital reoperation rates, and 47.2 percent of the variation in hospital complication rates. The discretionary use of operative features, such as the inclusion of bone morphogenetic proteins, accounted for 30 and 50 percent of the variation in surgeons' reoperation and complication rates, respectively.

Conclusions: To improve the safety of lumbar spinal fusion surgery, quality improvement efforts that focus on surgeons' discretionary use of operative techniques may be more effective than those that target hospitals.

Figure 1

Risk-Adjusted 90-Day Repeat Surgery (Top Row) and Complication (Bottom Row) Rates Following Inpatient Lumbar Spinal Fusion Surgery for Common Degenerative Diagnoses (Each spike represents 95 percent Bayesian confidence interval for the rates within a hospital (left) or surgeon nested within hospitals (right) in Washington State; the solid horizontal line represents the statewide mean)