Sequential correction technique in degenerative scoliosis with type C coronal imbalance: a comparison with traditional 2-rod technique

Abstract

OBJECTIVE The aim of this study was to compare the radiographic and clinical outcomes in patients with degenerative scoliosis (DS) with type C coronal imbalance who underwent either a sequential correction technique or a traditional 2-rod technique with a minimum of 2 years of follow-up. METHODS DS patients with type C coronal imbalance undergoing posterior correction surgery from February 2014 to January 2018 were divided into groups by technique: the sequential correction technique (SC group) and the traditional 2-rod technique (TT group). Radiographic parameters, including Cobb angle, coronal balance distance (CBD), global kyphosis (GK), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), and sacral slope, were assessed pre- and postoperatively. The SF-36 questionnaire was used to assess quality of life. RESULTS A total of 34 patients were included. Significant postoperative improvement in the Cobb angle of the main curve, CBD, GK, TK, LL, SVA, and PT was found in both groups (p < 0.05). Postoperatively, the coronal balance was type A in 13 patients (92.9%) in the SC group and in 16 patients (80.0%) in the TT group (p = 0.298). In the TT group, 1 patient had deteriorative coronal imbalance immediately postoperatively, and coronal imbalance deteriorated from type A to type C in 2 patients during follow-up. The scores of Physical Functioning, Role-Physical, Bodily Pain, Vitality, Social Functioning, Role-Emotional, and Mental Health were statistically improved postoperatively (p < 0.05) in both groups. Type C coronal imbalance at the last follow-up was associated with a relatively worse quality of life. There were no implant failures during follow-up in the SC group, whereas rod fracture was observed in 3 patients in the TT group. CONCLUSIONS Compared with the traditional 2-rod technique, the sequential correction technique can simplify rod installation procedure, enhance internal instrumentation, and reduce risk of implant failures. The sequential correction technique could be routinely recommended for DS patients with type C coronal imbalance.