Should Mandibular Symphyseal Distraction Osteogenesis be considered in OSA Surgery?

Abstract

Surgical maxillary expansion for the treatment of obstructive sleep apnea (OSA) has become common place. To maximize airway improvement, over-expansion of the maxilla can occur, resulting in an excessively widened maxilla that creates a mismatch to the mandible. Therefore, mandibular symphyseal distraction osteogenesis (MSDO) to widen the mandible along with maxillary expansion is being increasingly advocated in OSA surgery. The authors discuss their 20-year experience with MSDO and surgical maxillary expansion. They also analyze the airway impact between Distraction Osteogenesis Maxillary Expansion (DOME) and Endoscopically-Assisted Surgical Expansion (EASE) based on currently available computational fluid dynamic (CFD) data, which has implications in whether MSDO needs to be considered. The goal of surgical maxillary expansion is to enlarge the nasal cavity and reduce the airway resistance. CFD data demonstrates that EASE results in a much greater reduction in airway resistance as compared to DOME. EASE achieved a 12-fold reduction in nasal airway resistance compared to 3-fold reduction by DOME; a 12-fold reduction of retropalatal airway resistance as compared to 3-fold reduction by DOME; a 10-fold reduction of oropharyngeal airway resistance as compared to a 3-fold reduction by DOME, and an 8-fold reduction of hypopharygeal airway resistance as compared to a 3-fold reduction by DOME. Because there is no physiologic basis or data that demonstrates mandibular widening improves OSA, an airway centric surgical expansion technique such as EASE can achieve a much greater airway impact without needing excessive maxillary widening, thus eliminating the necessity MSDO.