The Impact of Provider Volume on the Outcomes After Surgery for Lumbar Spinal Stenosis

Abstract

Investigation into the provider volume-outcomes association for patients undergoing spine surgery has been limited. To examine the impact of surgeon and hospital volume on the outcomes after decompression with or without fusion for lumbar spinal stenosis. Data from the Nationwide Inpatient Sample (2005-2008) were retrospectively extracted. Multivariate logistic regression analyses were performed to calculate the adjusted odds of in-hospital mortality and the development of a postoperative complication with increasing surgeon or hospital volume. Provider volume was evaluated continuously and categorically, divided by percentiles into quintiles. Very-low-volume surgeons performed < 15 procedures over 4 years. All analyses were adjusted for differences in patient age, sex, comorbidities, and primary payer, as well as hospital bed size, teaching status, and location (urban vs rural). A total of 48,971 admissions were examined. In-hospital mortality did not differ significantly with increasing provider volume. When examined continuously, greater surgeon volume was associated with a significantly lower adjusted odds of developing a complication (odds ratio, 0.72; 95% confidence interval, 0.65-0.78; P < .001). Patients who underwent surgery by very-low-volume surgeons (odds ratio, 1.38; 95% confidence interval, 1.19-1.60; P = .001), but not those treated by low-, medium-, or high-volume surgeons, had a significantly higher complication rate compared with those who underwent surgery by very high-volume surgeons. After adjustment for surgeon volume, hospital volume was not significantly associated with in-hospital mortality or complications. In this nationwide study, patients treated by very-low-volume surgeons had a significantly higher complication rate compared with those treated by very high-volume surgeons.