Peak Timing for Complications After Adult Spinal Deformity Surgery

Background: Overall complication rates for adult spinal deformity (ASD) surgery have been reported; however, little data exist on the peak timing associated with specific complications. This study quantifies the peak timing for multiple complication types in an ASD cohort at minimum 2-year follow-up. Methods: Multicenter, prospective analysis of all complications after ASD surgery in a consecutively enrolled cohort was performed. Inclusion criteria were ASD, age ≥18 years, spinal fusion ≥4 levels, and minimum 2-year follow-up. Complications included major and minor and specific complication types. Peak timing of specific complications was identified and described. Regression analysis was performed to assess correlation between patient/surgical factors and complication timing. Results: There were 280 patients who met the inclusion criteria. Mean follow-up time was 2.9 years (range, 2–5 years). Of the patients, 209 (74.6%) had at least 1 complication, accounting for 529 total complications (258 minor and 271 major). Both major and minor complications peaked at <3 months. Infection and neurologic complications peaked at <3 months. Proximal junctional kyphosis had bimodal peaks at <3 and >24 months. Implant failure peaked at 12–24 and >24 months. There was a significant positive correlation between preoperative sagittal vertical axis and total complications at 6–12 months, major complications at 24 months, and reoperation. Body mass index was associated with total complications and implant failure at 12–24 and >24 months. Conclusions: The peak timing of specific complications after ASD surgery is identifiable. Understanding when these complications are likely to occur may improve patient counseling, early diagnosis, and prophylactic interventions and may help inform future reimbursement models.