Analysis of Clinical and Radiological Predictive Factors for Moderate and Severe Pulmonary Impairment in 102 Adolescent Idiopathic Scoliosis (AIS) Patients With Major Cobb Angle ≥45°: A Study of an Asian Population

STUDY DESIGN: Retrospective cohort study.

OBJECTIVE: To investigate the independent predictive factors for moderate-severe pulmonary impairment (MSPI) among adolescent idiopathic scoliosis (AIS) patients.

METHODS: The preoperative pulmonary function tests (PFTs) of 102 AIS patients (major Cobb angle ≥45°) operated between 2015 and 2020 were retrospectively reviewed. Patients were divided into 2 groups based on the predicted forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), respectively. Group 1 had normal/ mild pulmonary impairment (FVC or FEV1 >65% predicted) whereas Group 2 had MSPI (FVC or FEV1 ≤65% predicted). Multivariate logistic regression analysis was performed to determine the predictive factors for MSPI.

RESULTS: 41.2% (N = 42) and 52.0% (N = 53) of the total patients were categorised into Group 2 (MSPI) based on predicted FVC and FEV1, respectively. In general, Group 2 had more patients with a major main thoracic (MT) curve, larger MT curve with lower MT flexibility, a larger MT apical vertebra translation (MT-AVT), and a smaller thoracolumbar-lumbar (TL/L) AVT than Group 1 (P < .05). When analyzing the MT Cobb angle for every 10° increment, patients with MT Cobb angle ≥70° had MSPI (N = 31.4%). Body mass index (BMI) (FVC: aOR .8; FEV1: aOR .9) and MT Cobb angle (for every 10° increment, FVC: aOR 1.7; FEV1: aOR 1.8) were the significant independent predictive factors for MSPI.

CONCLUSION: MSPI was evident in patients with MT Cobb angle ≥70°, with MT Cobb angle and BMI being the significant independent predictive factors.