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

Dasenbrock, Hormuzdiyar H. MD*; Clarke, Michelle J. MD; Witham, Timothy F. MD§,¶,‖; Sciubba, Daniel M. MD§,¶,‖; Gokaslan, Ziya L. MD§,¶,‖; Bydon, Ali MD§,¶,‖

doi: 10.1227/NEU.0b013e318251791a
Research-Human-Clinical Studies: Editor's Choice
Editor's Choice
CNS University of Neurosurgery
Press Release

BACKGROUND: Investigation into the provider volume-outcomes association for patients undergoing spine surgery has been limited.

OBJECTIVE: To examine the impact of surgeon and hospital volume on the outcomes after decompression with or without fusion for lumbar spinal stenosis.

METHODS: 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).

RESULTS: 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.

CONCLUSION: 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.

ABBREVIATIONS: CI, confidence interval

ICD-9-CM, International Classification of Diseases, 9th revision, clinical modification

NIS, Nationwide Inpatient Sample

OR, odds ratio

*Department of Neurosurgery, Brigham and Women's Hospital/Children's Hospital Boston/Harvard Medical School, Boston, Massachusetts

Department of Neurosurgery, Mayo Clinic Medical Center, Rochester, Minnesota

§Spinal Column Biomechanics and Surgical Outcomes Laboratory

Department of Neurosurgery, and

School of Medicine, Johns Hopkins University, Baltimore, Maryland

Correspondence: Ali Bydon, MD, Department of Neurosurgery, Johns Hopkins University, 600 N Wolfe St, Meyer 5-109, Baltimore, MD 21287. E-mail:

Received November 26, 2010

Accepted January 11, 2012

Copyright © by the Congress of Neurological Surgeons