Magnetic resonance imaging assessment of airway status after orthognathic surgery.

The purpose of this study was to determine whether orthognathic surgical procedures create significant objective postoperative airway compromise or edema.A pilot magnetic resonance imaging (MRI) study was performed on 10 patients undergoing orthognathic surgical procedure to determine the time of maximum postoperative swelling, optimum time for scanning, and the anatomical sites of maximum swelling. Anatomical landmarks within the upper airway were determined. A prospective clinical study was then designed to assess the amount of postoperative airway edema in 40 patients undergoing orthognathic surgical procedure at the Toronto General Hospital. All patients received standard anesthetic and postoperative care. Magnetic resonance imaging scan of the upper airway from the hard palate to the subglottis was performed to assess the cross-sectional areas and volumes 24 to 48 hours postoperatively. The anteroposterior and transverse dimensions of the airway were measured at 3 anatomical points: the hyoid bone, the arytenoid cartilages, and the cricoid cartilage. One staff neuroradiologist assessed all MRI scans.The study group consisted of 24 female and 16 male patients, with a range of 15 to 36 years of age, and a mean of 23 years of age. A total of 56 Le Fort I osteotomies (25 advancements, 27 impactions, and 4 extrusions) and 30 bilateral sagittal split osteotomies (13 advancements, 17 setbacks) were included. Seven patients received single-jaw surgical procedures, 16 patients received double-jaw surgical procedures, and 17 patients received double-jaw as well as chin osteotomies. There was no clinical or radiological evidence of postoperative airway edema in any of the 40 patients irrespective of the type or number of osteotomies performed.Orthognathic surgical procedure involving osteotomies of the maxilla, mandible, and/or chin did not cause significant airway compromise or edema in the 40 patients studied. Once patients undergoing orthognathic surgical procedure fulfill postoperative extubation criteria, they can be safely extubated.