The value of drug-induced sleep endoscopy (DISE) is a topic that continues to be debated in otolaryngology, and experts took sides in a panel session held during the Triological Society Combined Sections Meeting, shedding light on the advantages and disadvantages of the procedure, as well as its efficacy in children with obstructive sleep apnea (OSA).
Jolie Chang, MD, assistant professor in the department of otolaryngology-head and neck surgery at the University of California San Francisco, said DISE, which involves a three-dimensional assessment of the airway during sedation that’s intended to mimic what happens during sleep, can be an asset in several ways. “It’s especially useful as a procedure for assessing the upper airway to determine surgical planning, candidacy for the hypoglossal nerve implant, and for surgical non-responders,” she said.
In comparisons with in-office awake exams, DISE has been found to be better at detecting more severe obstruction in OSA, particularly at the hypopharynx, and can pick up epiglottis obstruction that might not be seen in patients who are awake (Laryngoscope. 2013;123:2315-2318).
In a 2011 study of patients who had undergone uvolopalatopharyngoplasty (UPPP) but still had persistent sleep apnea, assessment with DISE found that half of these patients still had residual palate obstruction, and almost all had prominent hypopharyngeal obstruction (Laryngoscope. 2011;121:1320-1326). Furthermore, a more recent study found that DISE led to changes in surgical plans in half of cases, compared with plans made after the awake exam (Laryngoscope. 2016;126:768-774).
Cost Versus Outcomes
But David Steward, MD, professor of otolaryngology at the University of Cincinnati, Ohio, said the literature shows that DISE tends to lead to more procedures and more cost, without better results.
In a Level 1, randomized controlled trial, 39 patients selected for primarily palatal surgery by way of preoperative nasal pharyngoscopy were randomized to receive DISE and possibly additional procedures as a result. Both groups saw significant improvement in apnea-hypopnea index (AHI) and Epworth Sleepiness Scale (ESS) scores, but there were no significant differences between the groups. The DISE group was more likely to undergo additional procedures (Laryngoscope. 2015;125:2220-2225). “About 60% of patients had an additional procedure added, based on the sleep endoscopy, with no improvement in their outcomes,” Dr. Steward said.
Dr. Steward acknowledged there were findings that DISE led to changes in surgical plans but noted that there was no association found between outcome and the use of DISE (Laryngoscope. 2016;126:768-774).
Other studies found no change in outcome but noted greater cost and length of stay in UPPP cases and found that DISE had no predictive value for success at any level of multi-level pharyngeal surgery, including transoral robotic surgery (Laryngoscope. 2016;126:249-253; Laryngoscope. Published online ahead of print October 31, 2016. doi: 10.1002/lary.26255).
He did acknowledge the ability of DISE to predict success with upper-airway stimulation, although patients with palatal complete concentric collapse were not included in the pivotal Stimulation Treatment for Apnea Reduction (STAR) trial of the procedure because of poor results in such patients in a retrospective review.
Dr. Steward added, “There are several studies that show that the variation in the level of sedation and which agents you use result in different results of sleep endoscopy, at least in terms of our scoring, predominantly in the degree of obstruction.”
Stacey Ishman, MD, MPH, surgical director of the Upper Airway Center and associate professor of otolaryngology-head and neck surgery and pulmonary medicine at Cincinnati Children’s Hospital Medical Center, said cine MRI, a technique involving the review of more than 100 MRI images over a short span of time, and DISE are two reasonable alternatives to awake flexible endoscopy for evaluating the airway in children.
She said advantages of cine MRI include the fact that there is no radiation used and that several points of obstruction can be evaluated at the same time, making it easier to identify primary and secondary sites of obstruction.
Dr. Ishman said assessment of the size of the lingual tonsils and the adenoids is another asset. “One of the things you like it for is to quantify the size of the lingual tonsils,” she said. “What it helps me do is figure out the appropriate amount of OR time.” On the other hand, she said, it’s not very helpful for evaluation of the larynx and the nasal cavity and isn’t widely available.
Dr. Ishman said the use of DISE in children is evolving. “Persistent sleep apnea is the most common indication, but it’s also more commonly being done to look at kids who don’t have an obvious area of obstruction, [i.e.,] if they have small tonsils or no significant adenoids,” she said. “It also can be use in children with significant co-morbidities like obesity or Down Syndrome who have a very high likelihood of persistent sleep apnea after their tonsils come out.”
It can also be helpful in detecting sleep state-dependent laryngomalacia, although it can be difficult to tell whom to suspect for this condition, she said. One review involving 358 children with sleep-disordered breathing by a Canadian group found the condition was present in about 4% of children (Laryngoscope. 2010;120:1662-1666).
Dr. Ishman said the adult scoring systems used for DISE don’t include several factors that are relevant to evaluating children, and that the field needs a standardized scoring system for pediatric DISE.
Thomas Collins is a freelance medical writer based in Florida.