Residual T1 tilt could lead to poor self-image for patients with Lenke type 1 adolescent idiopathic scoliosis.

Abstract

Retrospective study. We aimed to investigate the clinical impact and risk factors for residual T1 tilt in patients with adolescent idiopathic scoliosis (AIS). We retrospectively analyzed data of patients with AIS and Lenke type 1 curves who underwent posterior fusion. Residual T1 tilt was defined as T1 tilt > 5° at 2 years postoperatively. Patients were classified based on the presence of residual T1 tilt: residual T1 tilt ( +) and residual T1 tilt (-) groups. Radiographic parameters and clinical outcomes were compared between the two groups. Among 128 patients, 44 (34.4%) had residual T1 tilt. The residual T1 tilt ( +) group had a significantly greater preoperative proximal thoracic (PT) curve, greater preoperative T1 tilt, and main thoracic (MT) curve correction rate than the residual T1 tilt (-) group. Shoulder imbalance and neck tilt rates at 2 years postoperatively were significantly higher in the residual T1 tilt ( +) group. The residual T1 tilt ( +) group had a significantly worse postoperative self-image score. Multivariate analysis identified the preoperative PT curve magnitude as an independent risk factor for residual T1 tilt. Receiver operating characteristic curve analysis identified a preoperative PT curve cutoff value of 26.5°. Achieving horizontalization of T1 tilt is vital to improve the self-image of patients with Lenke type 1 AIS. The study highlights the clinical impact of T1 tilt and identifies the preoperative PT curve magnitude as a significant independent risk factor. Level 4.