The Impact of Aesthetic Osseous Genioplasty on Upper Airway Volumes - A Single Center Retrospective Cohort Study.

[BACKGROUND] The effect of aesthetic osseous genioplasty on upper airway volume remains unclear, particularly the relative contributions of horizontal and vertical chin changes.

[METHODS] We retrospectively analyzed volumetric airway changes in 70 patients who underwent osseous genioplasty, using pre- and postoperative craniofacial CT scans (140 total). Image segmentation was performed to approximate volumes of the nasopharynx, oropharynx, hypopharynx, and total pharynx. Horizontal chin projection change was defined as the difference in anterior-posterior (AP) position of the osteotomized chin segment, and vertical change as lengthening or shortening based on inferior-superior movement of the pogonion, both measured between pre- and postoperative scans. Univariable and multivariable linear regressions were then performed to assess associations with airway volume change.

[RESULTS] Vertical chin lengthening was independently associated with oropharyngeal (β = 664.4 mm³, p = 0.015) and total airway volume (β = 917.6 mm³, p = 0.011) change, confirmed in univariable models (oropharynx: β = 728.0 mm³, p = 0.0047). Horizontal projection showed no significant associations across any airway region. Across the entire cohort, patients experienced net reductions in airway volume postoperatively, most notably in the oropharynx (-1270 mm³, p = 0.048) and total airway (-2801 mm³, p = 0.0016), particularly in cases with vertical chin shortening. Controls demonstrated minimal change. These findings suggest that vertical lengthening may increase airway patency, while vertical reduction may contribute to narrowing.

[CONCLUSION] Vertical movement of the osteotomized chin segment, both lengthening and shortening, was identified as a significant factor associated with postoperative airway change after genioplasty. This highlights the relevance of vertical repositioning in surgical planning and provides a basis for future studies on the functional effects of aesthetic genioplasty on the airway.