Surgical treatment of double thoracic adolescent idiopathic scoliosis with a rigid proximal thoracic curve.

Abstract

There is limited consensus on the optimal surgical strategy for double thoracic adolescent idiopathic scoliosis (AIS). Recent studies have reported that pedicle screw constructs to maximize scoliosis correction cause further thoracic spine lordosis. The objective of this study was to apply a new surgical technique for double thoracic AIS with rigid proximal thoracic (PT) curves and assess its clinical outcomes. Twenty one consecutive patients with Lenke 2 AIS and a rigid PT curve (Cobb angle ≥30º on side-bending radiographs, flexibility ≤30 %) treated with the simultaneous double-rod rotation technique (SDRRT) were included. In this technique, a temporary rod is placed at the concave side of the PT curve. Then, distraction force is applied to correct the PT curve, which reforms a sigmoid double thoracic curve into an approximate single thoracic curve. As a result, the PT curve is typically converted from an apex left to an apex right curve before applying the correction rod for PT and main thoracic curve. All patients were followed for at least 2 years (average 2.7 years). The average main thoracic and PT Cobb angle correction rate at the final follow-up was 74.7 and 58.0 %, respectively. The average preoperative T5-T12 thoracic kyphosis was 9.3°, which improved significantly to 19.0° (p < 0.0001) at the final follow-up. Although 71 % patients had preoperative level shoulders or a positive radiographic shoulder height, all patients had mildly imbalanced or balanced shoulders at the final follow-up. The average preoperative main thoracic apical vertebral rotation angle of 20.7° improved significantly after surgery to 16.4° (p = 0.0046), while the average preoperative total SRS questionnaire score of 3.7 improved significantly to 4.4 (p = 0.0012) at the final follow-up. Radiographic findings and patient outcomes were satisfactory. Thoracic kyphosis can be maintained or improved, while coronal and axial deformities can be corrected using SDRRT for Lenke 2 AIS with a rigid PT curve.