Respiratory status during sleep following orthognathic mandibular setback surgery

Objective: To investigate respiratory status and other clinical conditions pre- and postoperatively following sagittal splitting ramus osteotomy setback surgery. Patients and Methods: Eleven patients who underwent surgical correction of class III malocclusion were analysed. The surgical procedure consisted of bilateral sagittal splitting ramus osteotomy. The segments were fixed rigidly with titanium screws. For preservation of the airway, maxillomandibular fixation was not performed. The patients' respiratory status was evaluated using an apnoea monitor preoperatively, on the day of operation, I week postoperatively, and at more than 6 months postoperatively. The patients' pharyngeal morphology was also assessed by lateral cephalograms preoperatively, and 1 day and 6 months postoperatively. Results: The posterior airway space was decreased significantly immediately after surgery, but no remarkable changes were observed in the following 6 months. The Apnoea Hypopnoea Index and lowest saturation pulse oximetry were generally unaffected. However, in some patients, the respiratory status became worse immediately after surgery. Conclusions: Obstructive sleep apnoea syndrome is usually not provoked by mandibular setback surgery by the sagittal splitting ramus osteotomy procedure, despite the associated pharyngeal narrowing. However, careful observation is necessary because obstructive sleep apnoea syndrome is possible following surgery.