Changes in hypopharyngeal airway space and in tongue and hyoid bone positions following the surgical correction of mandibular prognathism.

This study was aimed at measuring the changes in the hyoid bone position, tongue position, and hypopharyngeal airway space in subjects with mandibular setback osteotomies. Lateral cephalometric radiographs of 15 patients were taken preoperatively, 6 weeks postoperatively, and at the follow-up with a mean of 1.5 +/- 0.4 years. A significant decrease in the hypopharyngeal airway space following mandibular setback surgery was found (P < .01). This change sustained during the follow-up period. The hyoid bone moved down (P < .001), and the lower tongue point also moved down (P < .05) postoperatively. Results of the study suggest that narrowing of the hypopharyngeal airway space due to the posterior and inferior movement of the tongue can be permanent.