A Pilot Study of the Level of Evidence and Collaboration in Published Neurosurgical Research

OBJECTIVE: Large-scale studies analyzing neurosurgical published research are lacking. This pilot study was designed to assess feasibility of an ongoing annual neurosurgical literature and research analysis of published articles in English-language neurosurgery journals. METHODS: All scientific articles published during 2015 in the print version of 14 English-language neurosurgery journals were reviewed individually. RESULTS: During 2015, 4065 articles were published in 14 neurosurgical journals. Of these, 1116 (27.5%) were nonscientific articles and were excluded from the analysis, and 2949 scientific articles were analyzed. Of these, 2% and 8.5% of publications met criteria for levels of evidence 1 and 2, respectively. One third of published manuscripts (33.2%) were retrospective chart reviews. There were 1742 different centers (mean 1.95 centers per article; range, 1-19) represented in 2949 articles from 67 countries (mean 1.23 countries per article; range, 1-12). Multicenter collaboration was present in 47.5% of published articles, and international collaboration was present in 17.5%. The highest numbers of U.S. author international collaborations were with Canada (70 collaborations), China (33 collaborations) and Italy (25 collaborations). Data for levels of evidence, multicenter collaborations, and international collaborations are presented for each individual journal and subject within neurosurgery. CONCLUSIONS: This pilot analysis provides a descriptive assessment of levels of evidence and collaboration based on journal, general subject matter, and subcategories of subject allowing for comparison. This methodology may be used on an annual basis to establish neurosurgery publication trends and to identify underrepresented areas of research within the specialty.