Effects of transverse maxillomandibular distraction osteogenesis on obstructive sleep apnea syndrome and on the pharynx.

PURPOSE: To assess the effects of transverse maxillomandibular distraction osteogenesis (TMDO) on the treatment of obstructive sleep apnea (OSA) and on the morphology of the pharynx. METHODS: A clinical trial was conducted with seven patients with OSA and with transverse maxillomandibular deficiency, two women and five men aged on average 41.16 +/- 10.9 years on the day of surgery. All participants were submitted to computed tomography (CT) and full-night polysomnography (PSG) before and approximately 9 months after surgery. A 95% confidence interval was defined. RESULTS: The AHI and RDI of the participants were reduced by about 62% (from 27.65 +/- 36.65 to 10.73 +/- 11.78, p = 0.031 and from 41.21 +/- 32.73 to 15.30 +/- 13.87, p = 0.015, respectively). The airway showed a surprising mean reduction in volume of 10% (from 5.78 +/- 2.53 to 4.71 +/- 1.42, p = 0.437, for the upper pharynx; from 6.98 +/- 2.23 to 6.23 +/- 2.05, p = 0.437, for the lower pharynx; and from 12.76 +/- 1.56 to 10.94 +/- 2.42, p = 0.625, for the total pharynx). However, the site of the smallest area of the pharynx was considerably increased both in the anteroposterior and transverse direction and in its total area (from 0.88 +/- 7.11 to 0.99 +/- 0.39, p = 0.625; from 1.78 +/- 0.81 to 2.05 +/- 0.61, p = 0.812; and from 0.99 +/- 0.74 to 1.40 +/- 0.51, p = 0.180, respectively). CONCLUSION: TMDO proved to be efficient in reducing or curing OSA, producing modifications of upper pharynx morphology with an increase of the smallest area of the pharynx.