Dynamic comparison of pharyngeal stability during sleep in patients with obstructive sleep apnea syndrome treated with maxillomandibular advancement.

PURPOSE: To compare the dynamic differences occurring in the pharynx during sleep after maxillomandibular advancement (MMA) surgery for the treatment of patients with obstructive sleep apnea syndrome.

METHODS: This was a prospective, cross-sectional study conducted on 20 patients (15 men and 5 women) with a polysomnography diagnosis of obstructive sleep apnea (OSA) submitted to surgical treatment with MMA. All patients were submitted to magnetic resonance (MR) during propofol-induced sleep before and 6 months after surgery. Thirty linear measurements (30 sections) were obtained over time in the retrolingual (RL) region to compare their variability before and after MMA.

RESULTS: The mean linear anteroposterior increase of the pharynx during induced sleep after MMA was 66 % in the RL region (P < 0.01). The coefficient of variation of the linear measurements was 117.5 % before surgery, being reduced to 51 % after surgery.

CONCLUSIONS: MMA promoted an important increase of the pharynx during induced sleep and a more significant change in the variability of its lumen. With a lower variation in the diameter of the organ during the respiratory movements, there is greater airway stability and a consequent maintenance of the pharyngeal lumen that reduces or even prevents pharyngeal collapse.