Topics in Training Variability in Spine Surgery Procedures Performed During Orthopaedic and Neurological Surgery Residency Training An Analysis of ACGME Case Log Data Alan H. Daniels, MD, Christopher P. Ames, MD, Justin S. Smith, MD, PhD, and Robert A. Hart, MD Investigation performed at the Warren Alpert Medical School, Brown University, Providence, Rhode Island Background: Current spine surgeon training in the United States consists of either an orthopaedic or neurological surgery residency, followed by an optional spine surgery fellowship. Resident spine surgery procedure volume may vary between and within specialties. Methods: The Accreditation Council for Graduate Medical Education surgical case logs for graduating orthopaedic surgery and neurosurgery residents from 2009 to 2012 were examined and were compared for spine surgery resident experience. Results: The average number of reported spine surgery procedures performed during residency was 160.2 spine surgery procedures performed by orthopaedic surgery residents and 375.0 procedures performed by neurosurgery residents; the mean difference of 214.8 procedures (95% confidence interval, 196.3 to 231.7 procedures) was significant (p = 0.002). From 2009 to 2012, the average total spinal surgery procedures logged by orthopaedic surgery residents in- creased 24.3% from 141.1 to 175.4 procedures, and those logged by neurosurgery residents increased 6.5% from 367.9 to 391.8 procedures. There was a significant difference (p < 0.002) in the average number of spinal deformity procedures between graduating orthopaedic surgery residents (9.5 procedures) and graduating neurosurgery residents (2.0 proce- dures). There was substantial variability in spine surgery exposure within both specialties; when comparing the top 10% and bottom 10% of 2012 graduates for spinal instrumentation or arthrodesis procedures, there was a 13.1-fold difference for orthopaedic surgery residents and an 8.3-fold difference for neurosurgery residents. Conclusions: Spine surgery procedure volumes in orthopaedic and neurosurgery residency training programs vary greatly both within and between specialties. Although orthopaedic surgery residents had an increase in the number of spine procedures that they performed from 2009 to 2012, they averaged less than half of the number of spine procedures performed by neurological surgery residents. However, orthopaedic surgery residents appear to have greater exposure continued Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors. Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. In addition, one or more of the authors has a patent or patents, planned, pending, or issued, that is broadly relevant to the work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article. e196(1) COPYRIGHT Ó 2014 BY THE J OURNAL OF BONE AND J OINT SURGERY,I NCORPORATED J Bone Joint Surg Am. 2014;96:e196(1-7) d http://dx.doi.org/10.2106/JBJS.M.01562