Evaluation of pharyngeal airway by cone-beam computed tomography after mono- and bimaxillary orthognathic surgery

Introduction: The aim of this study was to evaluate the changes of the pharyngeal airway obtained using mono-and bimaxillary orthognathic surgery in patients with skeletal malocclusion. Material and Methods: The analysis was conducted on cone-beam computed tomography images taken preoperatively and postoperatively of patients undergoing mono-or bimaxillary orthognathic surgery. The pharyngeal airway was divided into four airway volume segments and measured by planimetry. Results: The bimaxillary surgery group showed an increase in nasopharynx and velopharynx volumes and a decrease in glossopharynx and hypopharynx volumes (P < 0.05). The mandibular setback surgery group showed decreases in glossopharynx, hypopharynx, oropharynx, and pharynx volumes (P < 0.05). The mandibular advancement surgery group showed increases in glossopharynx, hypopharynx, oropharynx, and pharynx volumes (P < 0.05). The maxillary advancement surgery group showed increases in nasopharynx, velopharynx, and pharynx volumes (P < 0.05). Discussion and Conclusion: Mandibular setback surgery had a narrowing effect on the pharyngeal airway volume. Maxillary advancement surgery compensated for the constrictive effect of mandibular setback surgery on both the oropharynx and pharynx volumes. Although maxillary and mandibular advancement surgery affected different sites, these were the operations that contributed most to the increase in pharyngeal volume.