Incidence of and risk factors for revision surgery due to acute proximal junctional failure after anterior column realignment for adult spinal deformity.

Abstract

The association between the anterior column realignment (ACR) technique and acute proximal junctional failure (APJF) in adult spinal deformity (ASD) has not been thoroughly evaluated, and risk factors for revision surgery following APJF remain unclear. Therefore, this study was performed to determine the incidence of and the risk factors for revision surgery in APJF following ACR for ASD. Patients eligible for the study were those with severe degenerative sagittal imbalance who underwent deformity correction using ACR at 1 or more levels between 2020 and 2023. APJF was defined as proximal junctional failure occurring within 6 months postoperatively. Cases requiring revision surgery were classified as bony or soft tissue failures. Patient characteristics, surgical factors, and radiographic features were compared to identify risk factors for revision surgery. Univariate and multivariate logistic regression analyses were used to determine independent risk factors. The study included 114 patients (mean age 70.7 ± 5.3 years) with a mean fusion length of 7.2 ± 1.9 levels. APJF occurred in 36 patients (31.6%), with 24 cases of bony failure and 12 cases of soft tissue failure. Revision surgery was performed in 14 patients (38.9% of APJF cases, 12.3% of the study cohort) at a mean of 156.6 ± 76.2 days postoperatively. Among those revisions, 12 cases were due to bony failure and 2 to soft tissue failure. Univariate analysis identified a cranial screw angle at the upper instrumented vertebra (UIV), preoperative thoracic kyphosis (TK), postoperative TK, and proximal junctional angle (PJA) as significant risk factors for revision. Multivariate analysis revealed several independent risk factors for revision surgery: cranial screw angle at UIV (HR 21.578, p < 0.001), preoperative TK (HR 1.049, p = 0.034), and postoperative PJA (HR 1.125, p = 0.046). The incidence of revision surgery due to APJF following ACR for ASD was 12.3% overall. Key risk factors included a cranial UIV screw angle, greater preoperative TK, and increased postoperative PJA.