Three-dimensional evaluation of airway alterations post-orthognathic surgery in class III skeletal deformities

Orthognathic surgery is widely performed to correct skeletal Class III deformities and improve both function and aesthetic balance. However, surgical repositioning of the maxillomandibular complex can alter upper airway structure by affecting the spatial relationships among the mandible, tongue, and hyoid bone. This study aims to evaluate three-dimensional changes in the airway after bimaxillary orthognathic surgery in patients with skeletal Class III deformities and to analyze their association with cephalometric parameters and hyoid bone position.

Forty-nine patients with skeletal Class III deformities who underwent bimaxillary orthognathic surgery were retrospectively evaluated. Pre- and postoperative computed tomography scans obtained after a minimum of six months of follow-up were analyzed. Three-dimensional airway models were generated to measure nasopharyngeal, oropharyngeal, and total airway volumes, as well as the minimum cross-sectional area (MCA). Linear and angular cephalometric analyses were performed to assess maxillary and mandibular movements. Hyoid bone displacement was assessed relative to the third cervical vertebra (C3) and the mandibular base.

Significant reductions were observed in total and oropharyngeal airway volumes postoperatively, whereas nasopharyngeal volume decreased non-significantly. Despite these volumetric changes, the MCA remained stable. Airway volume changes were significantly correlated with mandibular displacement and hyoid-C3 distance. Nasopharyngeal airway volume was positively correlated with the maxillary occlusal plane angle.

Bimaxillary orthognathic surgery in patients with skeletal Class III deformities induces measurable three-dimensional airway alterations, predominantly in the oropharyngeal region. It also influences airway morphology, emphasizing the importance of considering airway changes during surgical planning.