Clinical and radiological factors associated with postoperative shoulder imbalance and correlation with patient-reported outcomes following scoliosis surgery.

Abstract

Shoulder balance (SB) is an important cosmetic concern and is a determinant to assess outcomes following scoliosis surgery. Shoulder imbalance (SI) has been studied predominantly in idiopathic scoliosis with limited literature on other etiologies. To assess SB following scoliosis surgery and correlate SRS-30 self-image scores with radiological shoulder imbalance SI. A retrospective analysis was performed for 43 patients undergoing scoliosis surgery with a minimum 2-year follow-up. Radiological SI was assessed by the coracoid height difference on whole spine standing radiographs at preoperative, 12-weeks postoperative and 2-year follow-up. The preoperative Cobb angle, postoperative Cobb angle and mean correction were recorded. The upper and lower end vertebrae (UEV/LEV), and instrumented vertebrae (UIV/LIV) were documented. The aetiology of scoliosis and functional outcomes based on the SRS-30 questionnaire were noted. There were 19 males and 24 females with a mean age of 14.5 ± 4.7 years. The 12-week postoperative radiographs showed SI in 15 patients and residual SI in 7 patients at 2-year follow-up. SI was seen in four congenital scoliosis with segmentation or mixed anomalies in the proximal thoracic spine. Two idiopathic scoliosis (Lenke type 1 and type 3) showed SI where the UIV was T3 and T2 respectively. The mean preoperative SRS-30 score for patients with SB (N = 9) was 2.5 ± 0.72 and for SI (N = 34) was 3 ± 0.42 without significant difference (p > 0.5). The final mean SRS-30 self-image score for patients with SB was 3.7 ± 0.54 and for patients with SI was 3.7 ± 0.53 without significant difference (p > 0.05). Radiological SI assessed by coracoid height difference was not associated with a significant difference in SRS 30 scores preoperatively and at 2 year follow up. SI was seen with congenital scoliosis associated with segmentation and mixed anomalies of the proximal thoracic spine.