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.

Objective: 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.

Methods: 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 ± 0.6 months postoperatively, and 6.2 ± 1.3 years 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.

Results: The subjects included 11 men and 12 women. Their mean age was 22.7 ± 4.7 years (range, 18 to 33 years). 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 6 months postoperatively. However, thereafter, no significant 2D or volumetric changes were observed until 6.2 years postoperatively. The long-term change of the LTW on the CV3 plane correlated negatively with mandibular relapse.

Conclusions: The volume and morphology of the 6-month postoperative changes in PAS were stable at 6 years for patients who had undergone maxillary advancement and mandibular setback.