DOS 2019

DOS Kongressen 2019 · 187 Mechanical complications following 3-Column Osteotomy surgery – A Competing Risk Survival Analysis in 193 consecutive Adult Spinal Deformity patients Tanvir Johanning Bari, Dennis Winge Hallager, Lars Valentin Hansen, Benny Dahl, Martin Gehrchen Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital; Department of Orthopedics and Scoliosis Surgery, Texas Children’s Hospital and Baylor College of Medicine, TX, USA Background: 3-Column Osteotomies (3CO) allow major surgical correction of Adult Spinal Deformity (ASD); although, the risk of mechanical complica- tions remains considerable. Previous reports of revision risk have been based on smaller cohorts or multicenter databases and none have utilized Competing Risk (CR) survival analysis. Purpose / Aim of Study: To report the incidence of revision surgery due to mechanical failure following 3CO surgery in patients with ASD. Materials and Methods: All ASD patients undergoing 3CO surgery from 2010-2015 at a single, tertiary institution were included. Demographics, long standing radiographs as well as intra- and postoperative complications were registered for all. A CR-model was used to estimate the incidence of revision surgery due to mechanical failure and covariates were assessed for prediction of failure and reported as odds ratios (OR) with 95% confidence intervals (95%CI). Findings / Results: A total of 193 patients were included with two- year fol- low-up available for 88% (mean [IQR]: 33 [24-49] months). Mechanical failure occurred in 120 cases (62%) at any time in follow-up, the most frequent be- ing rod breakage affecting 86 patients (45%). Cumulative incidence of revision surgery due to mechanical failure was estimated to 34% at two-years and 56% at five-years. A multivariable proportional odds model with death as competing risk showed significant higher odds of revision with increasing age (OR: 1.03; 95%CI: 1.00-1.05) and preoperative Pelvic Tilt (PT) >20° (OR: 2.14; 95%CI: 1.09-4.22). Type of 3CO, history of previous surgery, number of instrumented vertebra, as well as postoperative SRS-Schwab modifiers and Global Alignment and Proportion score were not associated with significant effects on odds of revision. Conclusions: In a consecutive single-center cohort of patients undergoing 3CO for ASD, we found an estimated incidence of revision surgery due to me- chanical failure of 34% 2-years postoperatively. Age and preoperative PT >20° were associated with elevated risks of revision. 143.