Anterior Vertebral Body Tethering (AVBT) in the Treatment of Adolescent Idiopathic Scoliosis: A Retrospective Study

Background/Objectives: Anterior Vertebral Body Tethering (AVBT) is a relatively novel minimally invasive surgical technique for the treatment of adolescent idiopathic scoliosis (AIS) that enables deformity correction of the spine diminishing vertebral motion reduction caused by the standard posterior spinal fusion approach. This paper reports the introduction of a new technical variant of AVBT, with the aim of evaluating its effectiveness on the correction of both axial and coronal spinal deformity. Methods: A single-centre single-surgeon retrospective cohort study was conducted. AVBTs were performed between 2020 and 2024. Radiographical values, surgical details, and complications of 67 patients affected by AIS were compared before surgery, immediately after surgery, and at the most recent follow-up. Results: Postoperative results have revealed a statistically significant coronal curve correction of 29.85% in the main thoracic (MT) curves (from mean preoperative width of 54.81 ± 11.86° to 38.45 ± 10.19°) and of 26.93% in the thoracolumbar (TL/L) curves (from 35.15 ± 11.83° to 25.69 ± 10.50°) in line with that obtained by the standard technique. Coronal correction at the most recent follow-up was maintained. Postoperative axial rotation reduction was found to be statistically significant in the main thoracic (MT) curves (from mean Nash-Moe value of 1.84 ± 0.71 to 1.36 ± 0.73), with a further decrease at the most recent follow-up compared with preoperative values. Improvement in other radiographical measures did not reach statistical significance and the complication rate was comparable to the standard technique. Conclusions: The extent of coronal correction in patients treated with the proposed modified AVBT technique is satisfactory and in line with results from studies testing the standard AVBT technique. The findings of this study seem to suggest that this technical variant of AVBT is effective in the correction of both axial and coronal deformity, with a surgical complication rate comparable to the standard technique.