DOS 2018

DOS Kongressen 2018 · 195 Revision Rate after Primary Adult Spinal Deformity Surgery - A nationwide study with two-year follow-up. Frederik Taylor Pitter, Martin Lindberg-Larsen, Alma Pedersen, Benny Dahl Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, University Hospital of Copenhagen; Department of Orthopedic Surgery and Traumatology, Odense University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Department of Orthopedic Surgery, Texas Children’s Hospital & Baylor College of Medicine Background: Revision rates following primary Adult Spinal Deformity (ASD) surgery have been reported to vary between 7 and 26 %. Most studies report loss to follow-up as a considerable limitation. Purpose / Aim of Study: To investigate revision rates after ASD surgery and reasons for revision. Materials and Methods: Nationwide cohort study with 2-year follow-up on all patients. Patients ≥18 years of age, undergoing primary instrumented surgery for ASD in Denmark between January 1st, 2006 and December 31st, 2014 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). All spinal revision procedures were identified. Medical records were reviewed to determine reason for revision and type of revision procedure. Overall comorbidities for each patient were summarized using the Charlson Comorbidity Index (CCI) based on data from DNPR. Findings / Results: A total of 553 patients were identified. Of these, 19.9% were revised within the 2-year follow-up and 7.2% of patients were revised more than once. The most common reason for revision was implant failure (38.2%) followed by infection (11.8%). Increased age (hazard ratio (HR) = 1.14 (95% confidence interval (CI) 1.02-1.27) per 10 years) and increased comor- bidity burden (CCI- score 1-2: HR= 1.54, 95%CI 1.01-2.34 and CCI- score ≥3: HR= 2.15, 95%CI 1.19-3.88) were associated with increased revision risk. Risk of revision increased from 2006 to 2014; year of primary surgery (2006 as reference) was associated with increased revision risk (HR= 1.10, 95%CI 1.02- 1.19). Conclusions: The revision risk within 2 years after primary ASD surgery was 20% nationwide in Denmark and implant failure was the most common reason for revision. Risk of revision surgery was positively correlated with increasing age and comorbidity burden. 136.