Risk Factors of Postoperative Coronal Balance Transition in Degenerative Lumbar Scoliosis.

Abstract

Retrospective radiographic study. To determine the potential risk factors influencing the transition of postoperative coronal balance in degenerative lumbar scoliosis (DLS) patients. As time passes after surgery, the spinal sequence of DLS patients may dynamically shift from coronal balance to imbalance, causing clinical symptoms. However, the transition of postoperative coronal balance and its risk factors have not been effectively investigated. We included 156 DLS patients. The cohort was divided into immediate postoperative coronal balance with follow-up balance (N=73) and follow-up imbalance (N=21), immediate postoperative coronal imbalance with follow-up balance (N=23) and follow-up imbalance (N=39). Parameters included age, sex, classification of coronal balance, coronal balance distance, fusion of L5 or S1, location of apical vertebra, apical vertebral translation (AVT), Cobb angle of main curve and lumbar-sacral curve, tilt and direction of L4/5, tilt and direction of upper instrumented vertebra (UIV), and Cobb angle of T1-UIV. Statistical testing was performed using chi-square/Fisher's exact test, t-tests or non-parametric tests, correlation testing, and stepwise logistic regression. We identified a significant difference in preoperative AVT, preoperative Cobb angle, and immediate postoperative UIV tilt between patients with and without follow-up balance. Logistic regression analysis demonstrated factors associated with follow-up coronal imbalance included preoperative AVT (P=0.015), preoperative Cobb angle (P=0.002), tilt of immediate postoperative UIV (P=0.018). Factors associated with immediate postoperative coronal imbalance patients with follow-up coronal balance were sex, correction ratio of main curve, and direction of L4. Logistic regression analysis further identified a correction ratio of main curve≤0.7 (P=0.009) as an important predictive factor. Patients with immediate postoperative coronal balance and higher preoperative AVT, preoperative Cobb angle, and tilt of immediate postoperative UIV were more likely to experience follow-up coronal imbalance. A correction ratio of main curve≤0.7 was an independent predictor of follow-up coronal imbalance. 3.