Purpose of the study: Multisegmentary pedicle screws are becoming increasingly popular for idiopathic scoliosis in adolescents. For several years correction of the axial deformity has been achieved by vertebral rotation. Use of the EOS radiographic system and the sterEOS software enables a precise calculation of the vertebral rotation in the different plans while exposing the patient to reduced radiation doses. The purpose of this study was to determine the efficacy of the vertebral rotation technique for the correction of axial rotation of the apical vertebra (ARAV).

Material and method: This was a comparative prospective study. Two groups of ten patients underwent surgery for idiopathic scoliosis of the thoracic spine (Lenke 1 and 3). A posterior procedure was performed in all cases to achieve insertion of multiple level pedicle screws. In group 1, the correction was achieved by rotation of the rod and in group 2 by translation and veterbral rotation using the vertebral column manipulation (VCM) technique. Preoperative and 3-month postoperative EOS images were analysed by a radiologist and the spinal surgeon, both blinded to the operative technique. Two radiological parameters were analysed and compared. ARAV was calculated using the pelvic reference; any position error at image acquisition was thus automatically corrected.

Results: Mean age at surgery was 14 years (range 11–19); the two groups were not significantly different for epidemiological parameters, duration of hospital stay, type of curvature, preoperative radiological parameters, axial rotation of the apical vertebra preoperatively, and number of vertebrae instrumented or correction of the curvatures. The postoperative ARAV was significantly greater in group 1 (12.4 vs 4.3, p=0.0005) and the ARAV correction was significantly greater in group 2 (13.7 vs 4.5, p=1.9E-5). There were no early postoperative complications in either group.

Discussion: For posterior surgical correction of thoracic or double major idiopathic scoliosis, the VCM technique allows better correction of the ARAV compared with the rod rotation technique. Use of the EOS and the sterEOS software enabled a better evaluation and comprehension of the 3D correction while exposing the patients to a smaller radiation dose.