Endoscopic examination of obstructive sleep apnea syndrome patients during drug-induced sleep.

Sixty patients diagnosed with obstructive sleep apnea syndrome (OSAS) underwent uvulopalatopharyngoplasty (UPPP). The effects of surgery were studied based on endoscopic findings during drug-induced sleep and determination of the apnea-hypopnea index (AHI) before and after the operation. Changes in the form of the airway during sleep in the recumbent position were observed, and the role of upper airway endoscopy in the diagnosis and surgical treatment of OSAS was determined. The site of airway obstruction during sleep induced by i.v. injection of 10 mg of diazepam was classified into five types, and changes in AHI and the site of airway obstruction were compared before and after surgery. Changes in airway morphology during sleep in the supine and recumbent positions were also compared before surgery. The postoperative improvement rate was 74.4% for the soft palatal type of obstruction, 76.2% for the tonsillar type, 53.3% for the circumferential palatal type and 34.0% for the mixed type. Treatment produced excellent or good effects for the soft palatal and tonsillar types of obstruction. However, many patients with the circumferential palatal and mixed types of obstruction showed only some improvement or no change. Good airway morphology was maintained in the recumbent position by patients with the soft palatal type of obstruction. With the circumferential palatal and mixed types of obstruction, improvement can be expected from operations which include surgical treatment of the posterior pharyngeal wall or lateral funiculus, or with midline laser glossectomy. A good operative outcome can be predicted in patients showing improvement of apnea in the recumbent position preoperatively.