Researchers conducted a retrospective study they sought to determine when adolescent idiopathic scoliosis (AIS) corrective surgery causes shoulder rebalancing and whether pedicle screws or hooks affect shoulder asymmetry. A retrospective review of 70 AIS patients undergoing AIS corrective surgery at a single institution was conducted. Anteroposterior x-rays were used to quantify radiographic parameters at preoperative, immediate postoperative, 6 months postsurgery, and 12 months postsurgery. The radiographic shoulder height (RSH), clavicle angle, coracoid height differential (CHD), and T1 tilt were measured. The proximal thoracic curve, significant thoracic curve, and thoracolumbar/lumbar curve have a Cobb angle. In addition, the percentage of correction was determined. From preoperative to 6 months after surgery, lateral shoulder asymmetry (RSH and CHD) changed dramatically. T1 tilt, a measure of medial shoulder asymmetry, remained unchanged. Up to 12 months after surgery, the hook group had considerably better shoulder balance than the screw group regarding RSH and CHD. However, the screw group had a significantly higher percentage correction of the thoracic curve than the hook group (hook: 62.2±18.4% vs screw: 76.0±16.0%, P=0.007). Rebalancing of the lateral shoulder could take up to 6 months after surgery. Hook structures offer better postoperative shoulder symmetry than thoracic pedicle screws in rectification of main AIS curves.
