Selective fusion in adolescent idiopathic scoliosis: a radiographic evaluation of risk factors for imbalance

STUDY DESIGN: Retrospective database, chart and medical imaging review. OBJECTIVES: To report on the outcome and evaluate possible risk factors for postoperative complications following selective spinal fusion in patients with adolescent idiopathic scoliosis (AIS). MATERIALS AND METHODS: All patients with AIS who underwent either a selective thoracic or selective thoracolumbar/lumbar spinal fusion at our institution from January 2001 to December 2011 inclusive were included in this study. The minimum postoperative follow-up period of all patients was 2 years. RESULTS: During the 11-year study period, 157 patients with AIS underwent surgery for their progressive spinal deformity. Thirty patients (19 %) had a selective spinal fusion, with 16 patients (group A) having a selective thoracic, and 14 patients (group B) having a selective thoracolumbar/lumbar spinal arthrodesis. In both groups the main postoperative complications were adding-on (25 % group A, 36 % group B) and coronal decompensation (25 % group A, 29 % group B). In group A, no statistically significant risk factors for postoperative complications were identified. In group B, global coronal balance was identified as a significant risk factor for adding-on. Patients with adding-on had significantly higher coronal balance scores (mean 3.6) than those who did not experience adding-on (mean 1.9) (p = 0.03). In addition, those with adding-on had a significantly smaller bending lumbar Cobb angle (mean 15) than those without adding-on (mean 31.6) (p = 0.015). None of the patients who underwent selective spinal fusion required revision surgery. CONCLUSION: Although the complication rate after performing a selective spinal fusion is high, the revision rate remains low and the debate whether or not to perform a selective spinal fusion will continue.