Changes in Upper Airway Volume Following Orthognathic Surgery.

Reduced volume of the internal skeletal dimensions of the face is 1 of the main causes of obstructive sleep apnea, and attention to patients' airways is necessary when planning orthognathic treatment. This study aims to describe changes in upper airway volume following virtually planned orthognathic surgery. A retrospective pilot study was designed with 30 randomly selected patients (10 men and 20 women, aged 23.1 +/- 6.8 years, molar-relations: 15 neutral, 8 distal, and 7 mesial). Cone-beam computed tomography scans were performed before surgery and 1 week following surgery. The authors did total upper airway volume measurements and obtained 1-mm slices at vertical levels in the velo-, oro-, and hypopharynx and at the smallest visible cross-section. Measurements before and after surgery were compared using Student t test. After orthognathic surgery, the minimum cross-sectional area at the vertical level increased from 83 mm3 +/- 33 before surgery to 102 mm3 +/- 36 after surgery (P = 0.019). In patients with neutral and distal occlusions, the minimum cross-sectional slice volume increased in 87% but in only 57% with mesial occlusion. The present findings suggest that orthognathic surgery increases upper airway volume parameters, but a few patients have continued impairment of the airways following orthognathic surgery. Further studies are needed to confirm an individual surgical planning approach that potentially could bring the minimum cross sectional area out of the risk zone. (C) 2016 by Mutaz B. Habal, MD.

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