DOS 2019

190 · DOS Abstracts Revision Surgery and Mortality following complex spine surgery in a prospective cohort of 679 patients – 2-years follow-up using the Spine AdVerse Event Severity (SAVES) system Tanvir Johanning Bari, Sven Karstensen, Mathias Dahl Sørensen, Martin Gehrchen, John Street, Benny Dahl Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital; Combined Neurosurgical and Orthopedic Spine Program, Vancouver General Hospital, University of British Columbia, Canada; Department of Orthopedics and Scoliosis Surgery, Texas Children’s Hospital & Baylor College of Medicine, TX, USA Background: Revision surgery and mortality are serious complications to spine surgery. Previous studies of frequency have mainly been retrospective, and to our knowledge, next to none have employed competing risk survival analyses. In addi- tion, assessment of predictors has focused on preoperative patient-characteristics. The effect of perioperative adverse events (AE) on long-term revision and mortality risk is not yet fully understood. Purpose / Aim of Study: To determine the 2-year risk of revision surgery and mortality after complex spine surgery, and to assess if prospectively registered AEs could predict either outcome. Materials and Methods: In 2013, we prospectively included all patients undergo- ing complex spine surgery at a single, tertiary institution. AEs were registered using the Spine Adverse Event Severity system. Patients were followed for a minimum of two years in regards to revision surgery and mortality. Incidences were estimated using competing risk survival analyses, and correlation between AEs and either out- come was assessed using proportional odds models. Findings / Results: We included 679 adult and pediatric patients. Demographics, surgical data, AEs and any event of revision or mortality were registered for all. The overall, 2-year, cumulative incidence of all-cause revision was 19% (16-22%) and all-cause mortality was 15% (12-18%). Deformity surgery was the surgical cat- egory with highest incidence of revision surgery, and the highest incidence of mor- tality was seen in the tumor group. We found that a major intraoperative AE was associated to threefold increased odds of revision. Deep wound infection was as- sociated to four-fold increased odds of mortality. Conclusions: We report the cumulative incidences of revision surgery and mortal- ity following complex spine surgery in a consecutive and prospective cohort of pa- tients. The incidence of revision surgery was higher across most surgical categories compared to previous retrospective studies. In addition, prospectively registered AEs were correlated to increased odds of revision surgery and mortality. The results presented in this paper may serve at reference for future interventional studies and as a simple tool to perioperatively identify unforeseen, at-risk patients. 146.