Posterior airways and orthognathic surgery: What really matters for successful long-term results?

Abstract

Although it is well known that orthognathic surgery modifies the upper airways, it is still unclear which are the determining factors to achieve adequate and predictable results in all the patients regardless of the initial malocclusion type and satisfying all the traditional orthognathic treatment objectives. This study aimed to correlate airway changes with surgical movements and other variables and the planning modalities to better understand how to control airway dimensions with treatment. This study involved 61 patients requiring bimaxillary surgery to correct various dentoskeletal deformities without a history of obstructive sleep apnea syndrome. In all the subjects, the orthosurgical treatment was planned according to the same treatment principles and regardless of the initial airway dimension. The 3-dimensional volume and minimal axial area values generated by cone-beam computed tomography at the preoperative, 3-week, and 1-year postoperative controls were evaluated and correlated with surgical movements and other variables. Although the planning did not consider the initial size of the airways, a significant increase was found for volume and minimal axial area in both the short term (volume, 29.0%; area, 51.2%) and long term (volume, 18.2%; area, 39.8%) with no regard to the type of malocclusion. Only 3 of the variables examined were found to significantly affect the airway: the preoperative dimensions, gender, and the extent of mandibular advancement. These 3 explanatory variables combined can predict the 1-year postoperative volume and minimal area with an accuracy of 71% and 44%, respectively. According to this study, orthosurgical treatment can protect airways from unexpected unfavorable changes and satisfy the other treatment goals regardless of the initial malocclusion as long as the facial deformities are properly addressed for each patient. Furthermore, these results identified 3 main variables that influence postoperative airways dimensions the most. Keeping in mind that the relationship between airway dimensions and obstructive sleep apnea syndrome is not clearly explained, these considerations may prove to be a useful tool to help in preventing and managing this disease. Studies involving larger samples of patients and evaluating more variables are mandatory to better understand the correlation between airways and sleep function.