Risk factors on re-imbalance of immediate postoperative coronal balance after corrective surgery for degenerative lumbar scoliosis

English Keywords:Degenerative lumbar scoliosis  Coronal balance  Balance transition  Risk factors

English Abstract:

  【Abstract】 Objectives: To explore the potential risk factors of final follow-up coronal imbalance in degenerative lumbar scoliosis(DLS) patients with immediate postoperative coronal balance after correction surgery. Methods: A retrospective analysis of 156 DLS patients treated at the Department of Orthopedics, Peking University Third Hospital between January 2010 and December 2020 was conducted. And 94 patients with immediate postoperative coronal balance(within 3 months) were included in the study. Parameters such as age, gender, preoperative coronal balance, fusion of L5 transverse process and S1, location of apical vertebra, apical vertebra translation(AVT), Cobb angles of main curve and lumbar sacral curve, and tilt direction and angle of L4; and immediate postoperative Cobb angles of main curve and lumbar sacral curve, tilt direction and angle of L4, tilt direction and angle of upper instrumented vertebra(UIV), and Cobb angle of T1-UIV were recorded. The patients were divided into final follow-up coronal balance group and final follow-up coronal imbalance group. The correlations between the previous parameters and coronal imbalance at final follow-up were analyzed. Results: A total of 94 DLS patients, including 15 males and 79 females, with an average age of 63.10±6.47 years were under immediate postoperative coronal balance status, and the follow-up duration was 32.5±26.9 months. 73 patients(77.7%) were of the final follow-up coronal balance group and the remaining 21(22.3%) were of the final follow-up coronal imbalance group. Comparison between the two groups showed statistically significant differences(P＜0.05) in preoperative AVT, preoperative Cobb angle, immediate postoperative Cobb angle of main curve, preoperative and immediate postoperative tilt angles of L4, and immediate postoperative tilt angle of UIV. Multivariate Logistic regression analysis showed that preoperative AVT(P=0.043), preoperative Cobb angle of main curve(P=0.018), immediate postoperative tilt angle of UIV(P=0.035) were independently associated with follow-up coronal imbalance for immediate postoperative coronal balance patients. Conclusions: Immediate postoperative coronal balance patients with greater preoperative AVT, preoperative Cobb angle of main curve, and immediate postoperative tilt angle of UIV were more likely to develop final follow-up coronal imbalance.