Abstract
Complications beyond 2-years after adult spinal deformity (ASD) surgery remain poorly characterized.
In patients undergoing ASD surgery, we sought to: 1) report the incidence of complications and reoperations beyond 2 years and 2) identify risk factors for late complications.
Retrospective analysis of prospective multicenter study.
A retrospective cohort study (2009-18) was performed of patients who underwent ASD surgery. Patients undergoing ASD surgery with ≥5 years of follow-up were included.
Primary outcome was mechanical complication beyond 2-years, including proximal junctional kyphosis/failure (PJK/F), rod fracture, and pseudarthrosis, reoperation, and patient-reported outcomes at >2 years. Secondary analysis evaluated specific predictors of late-onset mechanical complications. Sagittal alignment parameters were evaluated as T4-L1 within 4°, or L1-pelvic angle (L1PA) within 5° of target [(0.5 × pelvic incidence)-21°].
Bivariate analyses were performed.
Of 664 patients with ≥5-year follow-up (age:59±15 years; 76% females), late mechanical complications occurred in 40 (6%) patients, and 35/40 (88%) required reoperation. The most common complications were rod fractures (58%), proximal junctional kyphosis (PJK) (28%) and pseudarthrosis (13%). A history of prior complications was not associated with late complications (3% vs 7%, p=0.230). Despite no significant predictors of late complications or reoperations, patients with T4-L1PA mismatch >4° trended towards a higher rate of PJF (1% vs 0%, p=0.060). Regarding ODI, patients with mechanical complications (35 vs 27, p=0.015) and T4-L1PA mismatch (30 vs 25, p=0.043) had a higher ODI at 3 years. Patients with late mechanical complications continued to have higher ODI at last follow-up (35 vs 27, p=0.019).
Mechanical complications occurring beyond 2 years after ASD surgery affected approximately 1 in 20 patients, and 88% of these cases required reoperation. T4–L1 PA mismatch may predispose patients to PJF during the 2-5-year postoperative period. Patients who experienced late mechanical complications demonstrated sustained functional impairment, reflected by persistently higher ODI scores. These findings underscore the importance of long-term follow-up beyond 2-years and ongoing monitoring to optimize outcomes.
This abstract does not discuss or include any applicable devices or drugs.