Assessment of the pharyngeal airway space after mandibular setback surgery

Abstract

Background and Aim: Surgery for mandibular prognathism produces changes in the skeletal and soft tissue components of the orofacial complex. In particular, studies have shown changes in positions of the tongue and the hyoid bone and consequent narrowing of the pharyngeal airway space. This study evaluated the change in the pharyngeal airway space associated with surgical mandibular set back. Methods & Materials : Lateral cephalograms of 25 adult patients taken preoperatively and 3 months after mandibular setback surgery were traced, and the width of pharyngeal airway space and pharyngeal airway space area were calculated and compared by Paired T – test. Results : The mean amount of mandibular Set back was 6.8 ± 2 mm. There was not significant change in width of nasopharyngeal airway. Mean reduction in distance from uvula to the posterior pharyngeal wall was 1.4 ± 0.7 mm, mean reduction in distance from vallecula to the posterior pharyngeal wall was 2 ± 0.7 mm, mean reduction in the distance from the tongue base to the posterior pharyngeal wall was 2.5 ± 0.8 mm and the mean reduction in pharyngeal airway space area was 1.5 ± 0.5 cm 2 . The hyoid bone moved in an superoposterior direction. Conclusion : Mandibular set back surgery caused decrease in pharyngeal airway dimension. In the patients, who have other risk factors, for example, over weight, short necks, or large tongues, a mandibular set back procedure could possibly predispose the development of sleep apnea syndrome.