Three-Dimensional Changes in the Upper Airway of Skeletal Class III Patients After Different Orthognathic Surgical Procedures

Abstract

We hypothesized that 3-dimensional changes in the upper airway of patients with skeletal Class III malocclusion are different after mandibular setback and maxillary advancement (MSMA) compared with mandibular setback (MS) and that upper airway changes and the amount of jaw movement are correlated. Skeletal Class III patients who underwent MS surgery or MSMA surgery were included in this retrospective cohort study. Cone beam computed tomography scans were acquired before and 3months after surgery. Changes in the upper airway space were assessed as primary outcome variables. All cone beam computed tomography scans were imported into Dolphin Imaging software (version 11.7; Dolphin Imaging & Management Solutions, Chatsworth, CA) for reconstruction.SPSS software (version 22.0; IBM, Armonk, NY) was used for comparisons of the preoperative and postoperative changes within and between the groups, with analysis of correlations between upper airway changes and the amount of jaw movement. The study included 29 patients (13 in MS group and 16 in MSMA group). In the MS group, the velopharynx, glossopharynx, laryngopharynx, and total upper airway were significantly narrower after orthognathic surgery (P<.05). In the MSMA group, the velopharynx was significantly narrower after surgery (P<.05) whereas no statistically significant constriction was found in the other parts of the upper airway (P>.05). The velopharyngeal, glossopharyngeal, laryngopharyngeal, and total upper airway space in the MS group decreased significantly more than that in the MSMA group (P<.05). The upper airway was constricted more after MS surgery than after MSMA surgery. From the perspective of upper airway changes, MSMA leads to better outcomes than solely MS.