Examination of airway by computed tomography (CT) or cone-beam computed tomography (KIBT) in patients undergoing orthognatic surgery

Examination of Airway by Computed Tomography (CT) or Cone-beam computed tomography (CBCT) in Patients Undergoing Orthognatic Surgery Aim: The aim of this study is the evaluation of changes in the three-dimensional volume of pharyngeal airway obtained by single and bimaxillary mandibular orthognathic surgery in adult patients with severe skeletal malocclusion. Material and method: Our study was conducted on a of Computed Tomography (CT) or Cone-beam computed tomography (CBCT) of patients, with skeletal malocclusion and undergone orthognathic surgery, taken before and 6 month after treatment. Twenty-five adult patients (17 female, 8 male) were treated by bimaksillary orthognathic surgery, eight adult patients (6 female, 2 male) were treated by mandibular setback surgery, four adult patients (1 female, 3 male) were treated by mandibular advancemet surgery and five adult patients (3 female, 2 male) were treated by maxillary advancement surgery . Volumetric measurements of the pharyngeal airway were performed on these tomographys. The pharyngeal airway is divided into 4 airway volume segments; nasopharyngeal, velopharyngeal, glossopharyngeal, and hypopharyngeal and measured by planimeter. Six volume parameters (nasopharyngeal, velopharyngeal, glossopharyngeal, hypopharyngeal, oropharyngeal, pharyngeal) were created. Results: In the bimaxillary surgery group, increases in nasopharynx and velopharynx volumes and decreases in glossopharynx and hypopharynx volumes were observed (p <0.05). In the mandibular setback surgery group, decreases in glossopharynx, hypopharynx, oropharynx and pharynx volumes were observed (p <0.05). In the mandibular advancement surgery group, increases in glossopharynx, hypopharynx, oropharynx and pharynx volumes were observed (p <0.05). In the maksillary advancement surgery group, increases in nasopharynx, velopharynx and pharynx volumes were observed (p <0.05). Conclusion: Mandibular setback surgery was found to have a narrowing effect on pharyngeal airway volume. Maxillary advancement surgery compensated for the constrictive effect of mandibular setback surgery on both oropharynx and pharynx volume, even if bimaxillary orthognathic operations included mandibular setback surgery. Although maxillary advancement surgery and mandibular advancement surgery have affected different sites, these are the operations that contribute to increasepharyngeal volume and should not be avoided in the presence of indication, particularly in patients at risk of OSA.