Uniplanar cannulated pedicle screws in the correction of Lenke type 1 adolescent idiopathic scoliosis (AIS)

Abstract

Background In the present study, we reported the clinical use of uniplanar cannulated pedicle screws for the correction of Lenke type 1 adolescent Idiopathic scoliosis (AIS), and its safety and clinical outcomes were also evaluated. Methods 68 patients with Lenke type 1 AIS were included, among which 38 patients were treated with uniplanar cannulated screws at the concave side of periapical levels and multiaxial screws at the other levels (group A). Moreover, the remaining 30 patients were treated with all multiaxial screws (group B). The preoperative and postoperative radiographic parameters of the Lenke type 1 AIS, axial vertebral rotation, and the safety of the pedicle screws were evaluated by X-rays and computed tomography (CT). Results Preoperative data was comparable between two groups. The postoperative proximal thoracic (PT) curve, main thoracic (MT) curve, thoracolumbar/lumbar (TL/L) curve, and apical vertebral rotation were significantly improved compared with the preoperative data. The coronal correction rates in group A and B were 83% and 81.9%, respectively (P > 0.05). The derotation rates in group A and B were 60.8% and 43.2%, respectively (P < 0.05). The rotation classification in the group A was also better compared with the group B. The misplacement rate in group A and B was 7.9% and 11.8%, respectively (P < 0.05), and the total misplacement rate on the concave side (11.4%) was higher than that of convex side (8.4%). The lateral perforation was found at the concave side, while the medial perforation was found at the convex side. On the concave side, the misplacement rate in group A and B was 9.7% and 12.3%, respectively (P < 0.05). The grades 2 and 3 perforations were three (3.5%) in the group A and eight (8.2%) in the group B (P < 0.05). On the convex side, the misplacement rate in group A and B was 5.9% and 11.1%, respectively (P < 0.05). The grades 2 and 3 perforations were one (0.9%) in the group A and four (4.4%) in the group B (P < 0.05). Conclusion Collectively, uniplanar cannulated pedicle screws could effectively increase the accuracy of pedicle screws and facilitate the derotation of the apical vertebra compared with the multiaxial pedicle screws. Trial registration retrospectively registered