Effect of Mandible and Maxilla Osteotomies on Velar, Oropharyngeal, and Hypopharyngeal Diameter

Abstract

Purpose: There is a lack of anatomic comparisons between maxillomandibular advancement (MMA) and other bony surgical treatments of obstructive sleep apnea (OSA). Surgical procedures were simulated in cadavers to evaluate their ability to expand the posterior airway space (PAS). Materials and Methods: The following bony advancement surgeries were performed on each of 9 cadavers: genioglossal advancement (GGA); genioplasty with advancement of the genioglossus, geniohyoid, and anterior digastric muscles (GPA); bilateral sagittal split osteotomy; Le Fort I maxillary advancement; Le Fort I maxillary anterior impaction osteotomy (LFAI); MMA; MMA plus GPA; and MMA plus LFAI. Bony advancements were performed at increasing distances and change in PAS anteroposterior (AP) diameter was measured at the levels of the velum, oropharynx, and hypopharynx. Results: Change in PAS varied in a linear fashion with advancement surgical maneuvers. GPA led to a greater increase in AP distance at the levels of the oropharynx and hypopharynx compared with GGA. LFAI showed a greater increase in AP distance at the velum compared with MMA. All maxillary movements showed greater AP expansion in the PAS at the velum compared with mandibular advancements. Conclusions: Static AP expansion of the PAS at the levels of the velum, oropharynx, and hypopharynx occurs in a roughly linear and predictable pattern with different bony surgical procedures used in OSA surgery. MMA alone and MMA plus GPA had the overall greatest effect at all airway levels. GPA had a greater effect on expansion of the oropharynx and hypopharynx compared with GGA.