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Overlooked Sleep Endoscopy Metrics May Improve Hypoglossal Nerve Stimulation Outcomes


When considering HNS for treatment of obstructive sleep apnea, additional DISE metrics may inform patient response.

New research published in the July issue of Laryngoscopereports that currently overlooked drug-induced sleep endoscopy (DISE) findings are associated with outcomes after hypoglossal nerve stimulation (HNS), suggesting a more extensive role for DISE in procedure selection. The study is the largest to date to examine the association between DISE findings and HNS outcomes.

“HNS is the most exciting treatment for obstructive sleep apnea to come out in the past 20 years,” says Eric Kezirian, MD, senior author on the study and Vice Chair of the University of Southern California (USC) Caruso Department of Otolaryngology – Head and Neck Surgery at the Keck School of Medicine of USC

HNS is an option for individuals with moderate to severe obstructive sleep apnea who have not done well with continuous positive airway pressure (CPAP) therapy, the standard first line treatment. DISE is currently required as a preoperative evaluation to exclude individuals with complete concentric collapse related to the velum from receiving the treatment. According to the authors, this exclusion decision was based on an early study of 21 patients with obstructive sleep apnea which reported poorer outcomes with HNS in individuals with complete concentric collapse of the velum1.

“Because [HNS] is expensive and involves surgery, we wanted to learn more about whether we could go beyond the simplistic use of [DISC] and determine if there were other findings, currently ignored, that would place someone in a category of having better or worse outcomes,” says Dr. Kezirian.

The study included 343 participants from 10 medical centers who underwent HNS. Preoperative DISE videos were scored by four blinded reviewers using the VOTE Classification, which focuses on the primary structures that contribute to upper airway obstruction. DISE findings were examined for an association with surgical outcomes based on postoperative titration polysomnography (tPSG).

“[This was] an international, multicenter study based at USC, representing by far the largest study of its kind, and providing greater scientific rigor to the research than had been done previously,” says Dr. Kezirian.

Tongue-related obstruction was found to have the clearest association with increasing the odds of response to HNS (78% complete vs. 68% partial/none), particularly among patients with higher BMI.

In contrast, oropharyngeal lateral wall obstruction was associated with lower odds of surgical response (58% complete vs. 74% partial/none) and, similar to the tongue-related findings, the association was seen primarily in patients with a higher-than-average BMI. Epiglottis-related obstruction was associated with the lowest response rates.

Notably, Kezirian and colleagues report no statistically significant association between complete concentric collapse related to the velum and HNS outcomes.

“We believe that while this study is small (although there are no published studies with larger samples having this finding), it suggests that some patients with this DISE finding will respond well, even if the response rates are lower (58% with vs. 73% without),” wrote the authors. “It is worth noting that this figure is similar or higher than response rates seen with other DISE findings, specifically the oropharyngeal lateral walls and epiglottis.”

Altogether, the study suggests that the role for DISE in surgical selection for HNS should not be limited to excluding patients with complete concentric collapse related to the velum. To find out more, contact the USC Caruso Department of Otolaryngology – Head and Neck Surgery.

About the USC Caruso Department of Otolaryngology – Head and Neck Surgery:

Recognized as one of the top ear, nose and throat programs in the country by U.S. News and World Report, we offer leading-edge expertise and technological advancements in all seven of our subspecialties. From minimally invasive approaches to head and neck cancers to bioengineering research in hearing care, we’re able to provide some of the most advanced procedures available. 

  1. Vanderveken OM, Maurer JT, Hohenhorst W, et al. Evaluation of drug-induced sleep endoscopy as a patient selection tool for implanted upper airway stimulation for obstructive sleep apnea. J Clin Sleep Med. 2013;9(5):433-438. Published 2013 May 15. doi:10.5664/jcsm.2658
  2. Kezirian EJ, Hohenhorst W, de Vries N. Drug-induced sleep endoscopy: the VOTE classification. Eur Arch Otorhinolaryngol. 2011;268(8):1233-1236. doi:10.1007/s00405-011-1633-8