Selective thoracic fusion for adolescent thoracic scoliosis secondary to Chiari I malformation: a comparison between the left and the right curves.

Purpose: The aim of this study was to compare the clinical outcomes of selective thoracic fusion in the surgical treatment of Chiari malformation type I (CMI) adolescents with different curve patterns.

Methods: Sixty-three CMI patients with left thoracic curve (LTC) and 63 age- and curve-magnitude-matched CMI patients with right thoracic curve (RTC) were recruited. Selective thoracic fusion was performed for two groups. The coronal and sagittal parameters including the thoracic and lumbar Cobb angle, apical vertebral translation, trunk shift, thoracic kyphosis (TK), lumbar lordosis and sagittal vertical axis were measured before surgery, immediately postoperative and at the final follow-up. The accuracy of pedicle screw placement between both groups was also compared.

Results: All preoperative radiographic parameters were matched in both groups except for TK (LTC group 40.1° vs. RTC group 23.0°, P = 0.021). The immediately postoperative spontaneous correction of the lumbar curve was 56.9% in LTC group, which was remarkably lower than in RTC patients (67.9%). Patients with LTC were found to have obviously increased trunk shift than those with RTC (15.1 mm vs. 8.0 mm, P = 0.038). At the final follow-up, the correction of the thoracic curve was comparable between the two groups (59.9% vs. 62.6%, P = 0.610). The rate of the pedicle screw perforations was similar between both groups.

Conclusions: Patients with LTC and RTC can both be successfully corrected through selective thoracic fusion with a promising long-term surgical outcome. CMI patients with RTC tend to have a better spontaneous correction of the lumbar curve after surgery. These slides can be retrieved under Electronic Supplementary Material.