Influence of Bimaxillary Surgery on Pharyngeal Airway in Class III Deformities and Effect on Sleep Apnea: A STOP-BANG Questionnaire and Cone-Beam Computed Tomography Study

Abstract

Purpose: To evaluate pharyngeal airway space (PAS; nasopharyngeal, oropharyngeal, and total airway) volume and the correlation of an obstructive sleep apnea (OSA) and hypopnea syndrome screening questionnaire (STOP-BANG) with various mandibular setbacks during bimaxillary surgery and compare these findings with an age- and gender-matched skeletal Class I control group.

Patients and methods: This retrospective cohort study was composed of patients with skeletal Class III discrepancy who underwent bimaxillary jaw surgery and were assessed with STOP-BANG score, cephalometry, and cone-beam computed tomography (of the PAS). The predictor variable was bimaxillary jaw surgery and included 4-, 6-, and 8-mm setbacks. The primary outcome variables were PAS volume, body mass index, and STOP-BANG score evaluated at 1 week before surgery and after comprehensive orthodontic treatment (11.25 ± 1.95 months). Other variables were grouped into the following categories: demographic and cephalometric parameters. Statistical intragroup and intergroup differences were assessed by paired t and independent t tests (P < .05), respectively.

Results: The study sample was composed of 48 patients (18 to 25 yr old); group I received 4-mm setback (n = 16), group II received 6-mm setback (n = 16), and group III received 8-mm setback (n = 16) mandibular surgery, and all test groups received 4-mm maxillary advancement. The entire study group was compared with a skeletal Class I control group (n = 16). The total PAS volume after orthodontic treatment in groups I and II showed a significant decrease compared with the presurgical PAS (P < .001), but the decrease was not less than that in the control group (P > .05). In contrast, the total PAS volume in group III after orthodontic treatment (23,574 ± 1,394 mm³) was less than that in the control group (23,884 ± 1,543 mm³).

Conclusion: After surgery, patients with Class III discrepancy exhibited a decrease in oropharynx volume; however, the STOP-BANG score showed no change in risk factors scores for OSA at 4- to 8-mm setback surgery of the mandible in bimaxillary jaw surgery.