Objective: Determinate volumetric dimensional changes in the upper way at the nasopharynx and oropharynx level, after bimaxillary orthognathic and monomaxilar surgery.

Population, materials and method: Nineteen adult patients (12 men, 7 women) average age twenty-seven, with class III skeletal deformity, suitable for orthognathic surgeryCT Cone Beam was performed one week before the surgery and three months later, then, maxillofacial and otorhinolaryngologist clinical evaluation was performed. We analysed the normal distribution of variables with Shapiro Wilks; comparison between variables with normal distribution with test T with Wilcoxon signed-rank test.

Results: The preoperative maxillofacial-ENT evaluation of the nineteen patients indicated: Signs and symptoms of increased resistance of the upper airway: predisposition mild in nine (47.4%), moderate: seven (36.8%) and severe: one (5.3%). The clinical revaluation three months after orthognathic surgery showed a change in the predispositions 23% of the patients submitted to bimaxilar surgery. 15% changed their resistance from moderate to mild and 8% severe to moderate.

Conclusions: There is a tendency to increased volumetric dimension of the upper airways after orthognathic. Mandibular setback surgery reduces the volumetric dimensions of the oropharynx and maxillary advancement surgery outweighs the total volume of the upper airway.

Key words: oropharyngeal airway; monomaxilar surgery; bimaxillary surgery; obstructive sleep apnea