Assessment of Adult Spinal Deformity Complication Timing and Impact on 2-Year Outcomes Using a Comprehensive Adult Spinal Deformity Classification System

Study Design. Retrospective review of prospectively collected multicenter registry data. Objective. To identify rates and timing of postoperative complications in adult spinal deformity (ASD) patients, the impact of complication type and timing on health related quality of life (HRQoL) outcomes, and the impact of complication timing on readmission and reoperation rates. Better understanding of complication timing and impact on HRQoL may improve patient selection, preoperative counseling, and postoperative complication surveillance. Summary of Background Data. ASD is common and associated with significant disability. Surgical correction is often pursued, but is associated with high complication rates. The International Spine Study Group, AO Spinal Deformity Forum, and European Spine Study Group have developed a new complication classification system for ASD (ISSG-AO spine complications classification system). Methods. The ISSG-AO spine complications classification system was utilized to assess complications occurring over the 2-year postoperative time period amongst a multicenter, prospectively enrolled cohort of patients who underwent surgery for ASD. Kaplan-Meier survival curves were established for each complication type. Propensity score matching was performed to adjust for baseline disability and comorbidities. Associations between each complication type and HRQoL, and reoperation/readmission and complication timing, were assessed. Results. Of 584 patients meeting inclusion criteria, cardiopulmonary, gastrointestinal, infection, early adverse events, and operative complications contributed to a rapid initial decrease in complication-free survival. Implant-related, radiographic, and neurologic complications substantially decreased long-term complication-free survival. Only radiographic and implant-related complications were significantly associated with worse 2-year HRQoL outcomes. Need for readmission and/or reoperation was most frequent among those experiencing complications after postoperative day 90. Conclusion. Surgeons should recognize that long-term complications have a substantial negative impact on HRQoL, and should carefully monitor for implant-related and radiographic complications over long-term follow-up.