2008 Annual Meeting Abstracts

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PURPOSE: LeFort III distraction osteogenesis (DO) improves midface form and dental relationships, but its effect on the superior airspace remains undocumented. This study assesses the upper airway effects of LeFort III DO in patients with syndromic craniosynostosis.
METHODS: Retrospective single-institution review of all patients undergoing LeFort III DO from 2000 to 2006 (n=20). All study patients had a diagnostic quality lateral cephalogram preoperatively and one year postoperatively. Patients with preoperative evidence of obstructive sleep apnea (OSA) were evaluated by a pediatric otolaryngologist and sleep studies were obtained as needed. Changes in the velar angle, and the nasopharyngeal, velopharyngeal, oropharyngeal and hypopharyngeal spaces were measured cephalometrically. When available, preoperative and postoperative computer tomographic (CT) scans were also reviewed. Patients with moderate to severe OSA or tracheostomy were designated as having significant airway compromise. Cephalometric differences in the superior airspace were compared between patients with and without significant airway compromise.
RESULTS: Comparison between preoperative and postoperative cephalograms revealed an increased velar angle in relation to the cranial base (121° to 148°, p<0.001) and increased nasopharyngeal (3 mm to 13 mm, p<0.001) and velopharyngeal airspaces (2 mm to 6 mm, p<0.01). There were no significant changes in the oropharyngeal or hypopharyngeal airspace. CT analysis was consistent with the cephalometric results; however, a narrowing of the lateral aspects of the velopharyngeal space, relieved after distraction, was also noted. Comparison between preoperative cephalograms of patients with significant airway compromise (n=7) and patients without significant airway compromise (n=13) revealed, in the former group, decreased nasopharyngeal (2.1 mm to 4.8 mm, p<0.05) and velopharyngeal airspaces (1.0 mm to 2.5 mm, p=0.07) and no significant changes in the oropharyngeal and hypopharyngeal spaces. Of the 7 patients with significant airway compromise, 3 had both preoperative and postoperative sleep studies which showed improvement without complete resolution of their OSA.
CONCLUSION: LeFort III DO results in a statistically significant increase in the nasopharygeal and velopharyngeal airspaces and a horizontal change in the velar plane. There also appears to be a preoperative collapse of the lateral aspects of the velopharyngeal space that is relieved by midface distraction. When comparing preoperative cephalograms, patients with moderate to severe OSA or a tracheostomy had a statistically significant decrease in the nasopharyngeal and velopharyngeal airspace compared to patients without significant airway compromise. Midface distraction appears to improve but not resolve OSA.

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