Study design: A retrospective comparative study.
Objective: To evaluate the shoulder balance resulting from the correction of double thoracic adolescent idiopathic scoliosis (AIS) comparing rod derotation (RD) with direct vertebral rotation (DVR) and RD only after pedicle screw instrumentations.
Summary of background data: This is the first report on the effect of DVR on the shoulder balance using segmental pedicle screw instrumentation in the treatment of double thoracic AIS with minimum 5-year follow-up.
Methods: Patients with double thoracic AIS (n = 57) were treated by fusing both thoracic curves with RD and DVR (n=35), or RD (n=22) methods and retrospectively studied with a minimum 5 years of follow-up.
Results: In the RD with DVR group, the preoperative proximal thoracic curve of 40.2° improved to 17.9° postoperatively and 19.9° at the last follow-up. In the RD group, the preoperative proximal thoracic curve of 37.5° improved to 22.4° postoperatively and 23.2° at the last follow-up. In the RD with DVR group, the preoperative distal thoracic curve of 56.6° improved to 16.1° postoperatively and 16.7° at the last follow-up. In the RD group, the preoperative distal thoracic curve of 50.6° improved to 17.8° postoperatively and 18.2° at the last follow-up. In the RD with DVR group, the average preoperative shoulder height difference of 16.3 mm had improved to 7.2 mm postoperatively and was 7.0 mm at the last follow-up. In the RD group, the average preoperative shoulder height difference of 15.1 mm had changed to 7.5 mm postoperatively and was 7.3 mm at the last follow-up.
Conclusion: Shoulder balance had not significantly improved even with additional correction method of DVR using segmental pedicle screw instrumentation in double thoracic AIS. The proximal thoracic curve was rigid and corrected less in both groups. Therefore, less correction of the distal thoracic curve effectively achieves better shoulder balance.
Level of evidence: 3.