National adverse event profile after lumbar spine surgery for lumbar degenerative disorders and comparison of complication rates between hospitals: a CSORN registry study

OBJECTIVE Previous works investigating rates of adverse events (AEs) in spine surgery have been retrospective, with data collection from administrative databases, and often from single centers. To date, there have been no prospective reports capturing AEs in spine surgery on a national level, with comparison among centers. METHODS The Spine Adverse Events Severity system was used to define the incidence and severity of AEs after spine surgery by using data from the Canadian Spine Outcomes and Research Network (CSORN) prospective registry. Patient data were collected prospectively and during hospital admission for those undergoing elective spine surgery for degenerative conditions. The Spine Adverse Events Severity system defined minor and major AEs as grades 1–2 and 3–6, respectively. RESULTS There were 3533 patients enrolled in this cohort. There were 85 (2.4%) individual patients with at least one major AE and 680 (19.2%) individual patients with at least one minor AE. There were 25 individual patients with 28 major intraoperative AEs and 260 patients with 275 minor intraoperative AEs. Postoperatively there were 61 patients with a total of 80 major AEs. Of the 487 patients with minor AEs postoperatively there were 698 total AEs. The average enrollment was 321 patients (range 47–1237 patients) per site. The rate of major AEs was consistent among sites (mean 2.9% ± 2.4%, range 0%–9.1%). However, the rate of minor AEs varied widely among sites—from 7.9% to 42.5%, with a mean of 18.8% ± 9.7%. The rate of minor AEs varied depending on how they were reported, with surgeon reporting associated with the lowest rates (p < 0.01). CONCLUSIONS The rate of major AEs after lumbar spine surgery is consistent among different sites but the rate of minor AEs appears to vary substantially. The method by which AEs are reported impacts the rate of minor AEs. These data have implications for the detection and reporting of AEs and the design of strategies aimed at mitigating complications.