Background and aim: Orthognathic surgery for skeletal Class III malocclusion may affect upper airway dimensions. This study evaluated airway changes following bimaxillary surgery and isolated mandibular setback.
Material and methods: PubMed/MEDLINE, Embase, Scopus, and Web of Science were searched for eligible studies. Nineteen studies involving 683 participants were included. Upper airway dimensions were assessed using computed tomography or cone-beam computed tomography. Outcomes included total airway volume, regional nasopharyngeal, oropharyngeal, and hypopharyngeal volumes, and minimum cross-sectional area. Preoperative-to-postoperative changes were analyzed separately for each surgical approach, followed by between-group comparisons. Mean differences (MDs) and 95% confidence intervals were calculated using fixed-effect or random-effects models. Risk of bias was assessed using ROBINS-I.
Results: Following bimaxillary surgery, significant reductions were observed in oropharyngeal volume (MD: −1123.89 mm³; 95% CI: −1804.22 to −443.55) and hypopharyngeal volume (MD: −397.67 mm³; 95% CI: −726.89 to −68.46). Changes in total airway volume, nasopharyngeal volume, and minimum CSA were not statistically significant. Following isolated mandibular setback, significant reductions occurred in total airway volume (MD: −4580.29 mm³; 95% CI: −6597.04 to −2563.55), minimum CSA (MD: −61.63 mm²; 95% CI: −97.33 to −25.92), oropharyngeal volume (MD: −1748.32 mm³; 95% CI: −2237.31 to −1259.32), and hypopharyngeal volume (MD: −1429.16 mm³; 95% CI: −2232.20 to −626.12). Between-group differences were significant for total airway, nasopharyngeal, and oropharyngeal volumes, but not for minimum CSA or hypopharyngeal volume. Eighteen studies had serious and one had moderate overall risk of bias.
Conclusion: Both surgical approaches were associated with reductions in selected airway dimensions, with variations across anatomical regions and outcomes.