Three-Dimensional Changes in Pharyngeal Airway in Skeletal Class III Patients Undergoing Orthognathic Surgery

Purpose It has often been hypothesized that mandibular setback surgery causes narrowing of the pharyngeal airway. We examined whether the pharyngeal airway narrowed after orthognathic surgery in patients undergoing either mandibular setback surgery or bimaxillary surgery and whether the amount of narrowing of the pharyngeal airway was any different after mandibular setback surgery or bimaxillary surgery. Materials and Methods Cone-beam computed tomography scans were obtained for 21 patients who were assigned to either mandibular setback surgery or bimaxillary surgery. The anteroposterior dimension, lateral width, cross-sectional area, and volume of each subject's pharyngeal airway were measured before and after surgery. Results The pharyngeal airway showed significant narrowing after both mandibular setback surgery and bimaxillary surgery. The amount of change in the anteroposterior dimension and cross-sectional area on the posterior nasal spine plane and the length of the pharyngeal airway showed significant differences between the 2 groups. Conclusion The amount of narrowing of the pharyngeal airway was smaller in patients undergoing bimaxillary surgery than in the patients undergoing mandibular setback surgery.