Evaluation of pharyngeal airway volume and soft tissue changes after bimaxillary orthognathic surgery in skeletal class III patients using CBCT: Long-term Study

Background Bimaxillary surgery is increasingly used to correct Class III malocclusion, but concerns about potential airway narrowing and its role in obstructive sleep apnea (OSA) remain. This study aimed to evaluate the long-term effects of bimaxillary surgery on the upper airway and posterior soft tissues in skeletal Class III patients using Cone Beam Computed Tomography (CBCT). Methods In this retrospective descriptive-analytical study, fifty female patients (mean age, 35.17 ± 9.16 years) with mandibular prognathism were treated with LeFort I advancement nad bilateral sagittal split osteotomy. They all had under two score of STOP-BANG questionnaire. CBCT were performed before surgery and 5 years after surgery with standardized head and neck positioning. Airway volume and posterior soft tissue were analyzed using OnDemand 3D software version 10.0.1. Data were analyzed using independent t-tests, Pearson's correlation, and chi-square. Results in the long term, bimaxillary surgery statistically significantly increased the nasopharyngeal volume by 14.06% (P = 0.015) and decreased hypopharyngeal and upper airway volumes by 20.13% and 7.71% (P = 0.000, 0.015), respectively. Although there was a decrease in the oropharyngeal volume and the position of the soft palate, the changes were not statistically significant. The tongue moved backward by undergoing bimaxillary surgery (P = 0.005). No significant differences in STOP-BANG scores were observed. Conclusions Although bimaxillary surgery significantly reduces airway volume parameters, it does not elevate the risk of OSA in normal subjects. Our results can aid orthodontists and oral surgeons in selecting the proper surgical method.