Cone-Beam Computed Tomography Evaluation of Pharyngeal Airway Space Changes After Bimaxillary Orthognathic Surgery in Patients With Class III Skeletal Deformities: A 6-Year Follow-Up Study

Abstract

The aim of the present study was to investigate the volumetric and 2-dimensional (2D) changes in the pharyngeal airway space (PAS) after bimaxillary orthognathic surgery (maxillary advancement and mandibular set back) in patients with skeletal Class III deformities. In the present retrospective study, patients with skeletal Class III deformities were treated at Pusan National University Hospital (Busan, South Korea) and had undergone cone-beam computed tomography examination preoperatively, immediately postoperatively, 6.0±0.6months postoperatively, and 6.2±1.3years postoperatively. The anteroposterior length (APL), largest transverse width (LTW), and cross-sectional area (CSA) at 4 reference planes and the PAS volume were measured. Spearman's correlation analysis was used to assess the correlation between the PAS changes and skeletal movements. The subjects included 11 men and 12 women. Their mean age was 22.7±4.7years (range, 18 to 33years). The APL and CSA on the PNS-Vp, CV1, and CV2 planes, the LTW on the CV1 plane, and the oropharyngeal and total volume had decreased at 6months postoperatively. However, thereafter, no significant 2D or volumetric changes were observed until 6.2years postoperatively. The long-term change of the LTW on the CV3 plane correlated negatively with mandibular relapse. The volume and morphology of the 6-month postoperative changes in PAS were stable at 6years for patients who had undergone maxillary advancement and mandibular setback.