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

Study design: Retrospective study.

Purpose: We aimed to investigate the clinical impact and risk factors for residual T1 tilt in patients with adolescent idiopathic scoliosis (AIS).

Methods: 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.

Results: 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°.

Conclusion: 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 of evidence: Level 4.