Upper airway changes after mandibular advancement surgery combined with minimal maxillary displacement: A preliminary cone-beam computed tomography 12 month minimum follow-up controlled study.

BACKGROUND

The purpose of this study was to analyze airway volume and minimum cross-sectional area (CSA) in a postsurgical follow-up period of at least 12 months in patients after mandibular advancement surgery with minimal maxillary displacement compared with nonsurgical patients with Class I malocclusions (control group).

METHODS

The study sample included 14 patients in the surgical group and 14 patients in the control group. Linear, angular, area, and volume measurements were obtained to characterize the sample and assess the outcomes. Comparisons were made among measurements taken before treatment, at least 1 month after surgery, and at follow-up at least 12 months after surgery.

RESULTS

Substantial anteroposterior changes in the mandible and hyoid bones, with minor maxillary movement, were observed. Pharyngeal airway volume increased considerably after surgery, maintaining stability, yet there were no substantial changes observed in the velopharynx and oropharynx. The minimum CSA increased in the postsurgery period and was maintained in the follow-up. Results of correlation analysis revealed negative associations between hyoid displacement and changes in pharyngeal airway volume and CSA. This suggested that when the hyoid bone shifted forward in the anteroposterior direction, it was correlated with an enlargement in pharyngeal airway dimensions.

CONCLUSIONS

The greatest increase was seen in pharyngeal airway total volume and CSA, and these changes were stable in the follow-up period.

PRACTICAL IMPLICATIONS: Mandibular advancement surgery with minimal maxillary displacement may lead to significant and stable increases in pharyngeal airway dimensions, benefitting patients with narrower pharyngeal airways and potentially higher risk of breathing disorders.