Effect of postoperative trunk shift on long-term shoulder imbalance after single segment hemivertebra resection in children: risk factors and prognosis / 中华骨科杂志

ABSTRACT

Objective:To investigate the risk factors of long-term shoulder imbalance in patients presented postoperative shoulder imbalance who underwent single segment hemivertebra resection, and the role of postoperative trunk shift in shoulder imbalance.Methods:All of 30 patients who presented shoulder imbalance after hemivertebrae resection and short fusion from July 2006 to December 2018 were reviewed in this study, including 16 males and 14 females, aged 4.53±2.05 years (range, 2-8 years). Among them, 10 cases were thoracic hemivertebra, 12 thoracolumbar hemivertebra and 8 lumbar hemivertebra. According to the vertical height difference at the highest point of soft tissue shadows on both shoulders in the final follow-up upright posteroanterior radiograph, which was shoulder imbalance (SI), they were divided into two groups Group B (balance, shoulder imbalance less than 10 mm) and Group IB (imbalance, shoulder imbalance more than 10 mm). Several radiographic parameters were measured preoperatively, 3 months after surgery and at the final follow-up, such as SI, distance between C 7 plumbline and center sacral vertical line (C 7PL-CSVL), Cobb angle of main curve, cobb angle of proximal curve (CAPC), Cobb angle of distal curve (CADC), upper instrumented vertebra offset (UO), lower instrumented vertebra offset (LO), upper instrumented vertebra slope (US), lower instrumented vertebra slope (LS), T1 tilt and sagittal vertical axis (SVA). Results:The mean follow-up period was 54.3±33.7 months (range, 24-132 months). A mean of 3.1 segments were fused. 7 cases (70%) of thoracic, 6 cases (50%) of thoracolumbar and 3 cases of lumbar hemivertebrae (37.5%) with shoulder imbalance at 3 months after surgery remained imbalanced at the last follow-up. Thirteen cases presented coronal imbalance postoperative (C 7PL-CSVL>2 cm), among 6 cases whose trunk shafted to the side of the higher shoulder postoperatively, 5 cases presented aggravated SI at final follow-up, and among 7 cases whose trunk shafted to the side of the lower shoulder postoperatively, 6 cases presented aggravated SI at final follow-up, while the difference had statistical significance ( P=0.029). The static analysis indicated that postoperative and long-term C 7PL-CSVL, long-term lowest instrumented vertebra and long-term T 1 tilt were risk factors of shoulder imbalance at final follow-up. Conclusion:A proportion of congenital scoliosis patients who presented shoulder imbalance after hemivertebra resection plus short fusion are less likely to achieve shoulder balance at the final follow-up. Long-term shoulder imbalance is often presented in the patients whose trunk shafted to the side of the higher shoulder postoperatively.