Background and objectives: The purpose of this study was to retrospectively evaluate pharyngeal airway space (PAS) changes in patients who received mono or bimaxillary surgeries with bone displacement.

Methods: A cephalometric evaluation of 18 normal Chilean patients, after an orthognathic surgery. Only patients with pre and post operatory profile teleradiography were selected for this study. The radiographies were standardized in postural head position, without olives and in first teeth contact. Pre and post images had to be at the same scale (1:1). The patients were divided into 2 groups: group 1 underwent monomaxillary (Le Fort) advance surgery (9 patients); group 2 underwent bimaxillary advance surgery (9 patients). The PAS was evaluated with a handcraft cephalometric analysis of one operator, between one week postoperatively and six months postoperatively.

Results: Monomaxillary surgery evidenced, when the bone movement was at least 5 mm, occurred a wide increase at all pharyngeal levels (posterior nasal spine = 7 mm; soft palate = 6 mm; tongue = 9 mm; hyod = 4 mm). Bimaxillary surgery showed changes at PAS when the maxillar displacement was ≥8 mm, while the mandibular was at least >4 mm (posterior nasal spine = 9 mm; soft palate = 2 mm; tongue = 2 mm).

Conclusion: The goal of this study was to understand and to predict the airway changes in orthognathic surgery. We propose a novel method to predict and planning surgeries in patients with some airway alterations like sleep apnea. This study made possible determines a numeric correlation between bone movement and the pharyngeal airway dimension changes. This could be a useful tool to predict the amount of the bone movement and improve the airway in orthognathic surgery patients.

Key words : bone; displacement; correlation; pharyngeal; orthognathic