Nonresponders to pharyngeal surgery for obstructive sleep apnea: insights from drug-induced sleep endoscopy.

OBJECTIVES/HYPOTHESIS To examine drug-induced sleep endoscopy (DISE) findings in nonresponders to previous pharyngeal obstructive sleep apnea (OSA) surgery. STUDY DESIGN Cross-sectional. METHODS DISE using propofol for unconscious sedation was performed in nonresponders to previous OSA surgery (including palate surgery with or without tonsillectomy and possible other procedures). Nonresponders were defined as subjects with a postoperative apnea-hypopnea index more than 10 events/hr. Recorded findings from DISE included the presence and degree of obstruction in the palatal and hypopharyngeal regions, the contributions of specific structures (velum, oropharyngeal lateral walls, tongue, and/or epiglottis) to upper airway obstruction, and the degree of mouth opening. RESULTS Thirty-three nonresponders underwent DISE examinations. Age was 46.2 ± 11.8 years, and 9% (3 of 33) were female. On diagnostic sleep studies prior to DISE, the apnea-hypopnea index was 43.4 ± 26.6 events/hr. During DISE, a majority of subjects demonstrated residual palatal obstruction, and almost all demonstrated hypopharyngeal obstruction. A diversity of individual structures contributed to upper airway obstruction, often in combination. Moderate to severe mouth opening occurred in one-third of subjects and was associated with narrowing of upper airway dimensions. CONCLUSIONS Residual upper airway obstruction in surgery nonresponders likely occurs due to multiple mechanisms, and DISE may enhance the understanding of them.