Effects of Mandibular Retropositioning, with or Without Maxillary Advancement, on the Oro-naso-pharyngeal Airway and Development of Sleep-related Breathing Disorders

Purpose: Literature suggests that patients without pre-existing sleep-related breathing disorders who undergo orthognathic surgery for treatment of facial asymmetry may experience changes in their oropharyngeal airway. Mandibular retropositioning can compromise the posterior airway space, alter the physiologic airflow through the upper airway, and predispose patients to development of obstructive sleep apnea syndrome (OSAS).

Patients And Methods: This study was a retrospective cohort analysis of 26 patients who underwent mandibular retropositioning with or without maxillary advancement within the past 5 years at Tufts University School of Dental Medicine. Pre- and postoperative lateral cephalometric radiographs were analyzed with digital DOLPHIN software (Dolphin Imaging, Chatsworth, CA) for evidence of changes to the posterior airway dimension. In addition, patients were evaluated postoperatively with SNAP polysomnography (model 4/6; SNAP Laboratories, Wheeling, IL) for evidence of OSAS.

Results: Results indicated that mandibular retropositioning greater than or equal to 5 mm decreased the posterior airway space below 11 mm (30.75%, P = .03) and showed evidence of soft palate elongation greater than 32 mm (15.39%, P = .037) in a significant number of patients. However, as determined by cephalometric analysis, mandibular retropositioning greater than or equal to 5 mm in combination with maxillary advancement had no significant effect on the posterior airway space or soft palate.

Conclusion: Postoperative SNAP polysomnography showed higher incidence of mild to moderate OSAS in patients who underwent mandibular retropositioning greater than or equal to 5 mm (69.25%) compared with patients who underwent mandibular retropositioning in combination with maxillary advancement (38.46%, P = .039).