2021 Volume 12 Issue 5 Pages 723-728
Introduction: Reducing mechanical complications (MCs) after adult spinal deformity (ASD) surgery is challenging. This study aimed to identify predictive factors of MCs after ASD surgery.
Methods: Fifty-one patients (mean age, 71.2 years) who underwent thoracic-to-pelvis ASD surgery with ≥2 years follow-up were retrospectively reviewed. MCs included proximal junctional kyphosis (PJK), rod breakage (RB), and implant-related complications. Patient- and surgery-related factors, radiographic parameters (including spinopelvic), and postoperative global alignment and proportion (GAP) scores were compared between the non-MC and MC groups. A Cox proportional-hazards model was used to identify predictive factors of MCs.
Results: MCs occurred in 30 (59%) patients, and 31% of all patients required revision surgery. PJK was found in 33% (revision rate, 29%), and RB was found in 31% (revision rate, 69%). A higher rate of MCs was observed in three-column osteotomy (10% vs.37%, P = 0.048). The preoperative sagittal vertical axis (113 mm vs.144 mm, p = 0.044) and postoperative GAP score (4.4 vs.6.3, p = 0.026) were significantly higher in the MC group. The GAP score was an independent predictive factor associated with MCs (hazard ratio 1.357, 95% confidence interval 1.072-1.718, p = 0.011), and receiver operating characteristic curve analysis revealed that a GAP cutoff score of 8 points predicted revision surgery for MCs.
Conclusions: Among all patients, MCs occurred in 59%, and 31% required revision surgery. The GAP score was an independent predictive factor associated with MCs. Achieving proportional sagittal alignment may decrease the occurrence of MCs.
