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Drug-Induced Sleep Endoscopy Provides Insight into OSA

by Sue Pondrom •

Can drug-induced sleep endoscopy (DISE) help determine the mechanisms for lack of response to surgery for obstructive sleep apnea (OSA)?

Background: The most common OSA surgical treatment in the U.S. is isolated palate surgery, even though it rarely eliminates OSA and achieves a meaningful reduction in severity in only 5 percent to 38 percent of patients. In an attempt to improve surgical outcomes, surgeons have performed hypopharyngeal procedures in combination with palate surgery, increasing the response rate to 35 percent to 62 percent of patients. Although several studies investigated palate and/or hypopharyngeal procedures, few have looked at non-responders to determine the mechanisms of response to surgery.

Study Design: Cross-sectional study.

Setting: Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco.

Synopsis: DISE, using propofol for unconscious sedation, was performed in 33 non-responders who had a post-surgery apnea-hypopnea index of more than 10 events per hour. A majority of subjects demonstrated residual palatal obstruction, and almost all demonstrated hypopharyngeal obstruction. Moderate to severe mouth opening occurred in one-third of patients and was associated with narrowing of upper airway dimensions. Oropharyngeal lateral wall prolapse was associated with poorer outcomes. Although unconscious sedation under propofol is not a perfect simulation of natural sleep, the authors found that pharyngeal dilator muscle activity appears to lie somewhere between non-rapid eye movement (NREM) and REM sleep. Limitations of the study included subgroups not differentiated by age, gender and race/ethnicity; primary surgery performed by multiple surgeons in multiple institutions; and no comparison to preoperative and postoperative findings given that subjects did not undergo DISE prior to primary surgery.

Bottom Line: Evaluation techniques such as DISE may enhance the understanding of the multiple mechanisms leading to residual upper airway obstruction.

Citation: Kezirian EJ. Nonresponders to pharyngeal surgery for obstructive sleep apnea: insights from drug-induced sleep endoscopy. Laryngoscope. 2011;121:1320-1326.

—Reviewed by Sue Pondrom