Obstructive sleep apnea and snoring are common, but it is naive (and incorrect) to think that any single approach is going to work for all patients. This is true for CPAP and is clearly true for surgical procedures and oral appliances. I have written previously on working with sleep dentists to evaluate whether a certain patient might be a better candidate for surgery, an oral appliance, or a combination of these approaches. I have also written about how drug-induced sleep endoscopy (DISE) can provide key insight into whether a patient might respond to oral appliances. This past month another research study now available online through the Journal of Clinical Sleep Medicine provided even clearer evidence of how valuable DISE can be in predicting oral appliances outcomes in sleep apnea patients.

During DISE, many of us will observe the throat while someone advances the lower jaw (mandible). The idea is that this somewhat simulates the effect of an oral appliane (specifically, the most common type called a mandibular advancement device). While the so-called Esmarch maneuver is not the same as the movement of these oral appliances, it does allow us to – in general terms – evaluate the potential of mandibular advancement to open the airway for breathing (and, ostensibly, treat obstructive sleep apnea). There are a number of criticisms of the Esmarch maneuver, whether it is that there is no quanitative measurement of the amount of mandibular advancement, that oral appliances are also open the mouth slightly (with potential adverse consequences), and/or the sedation during DISE is not natural sleep. All of these are true, but I (and many others) feel that they simply make the Esmarch maneuver imperfect but still useful.

Previous studies, while important, did not evaluate the findings during mandibular advancement in the most detailed way, often limiting the analyses to assessment of whether mandibular advancement opened the airway for breathing or not. This just-published study examined some of the other maneuvers done during DISE, such as the Esmarch maneuver and chin-lift maneuver that simply closes the patient’s mouth, either completely or almost completely. During each of these, they recorded whether the airway opened completely and, if not, what was the source of residual airway obstruction. They showed that opening of the airway during the Esmarch maneuver was associated with better oral appliance outcomes, whereas the ability of the other maneuvers to open the airway had no association with oral appliance outcomes. That being said, if there was continued evidence of oropharyngeal lateral wall-related obstruction during any of these maneuvers, this was associated with poorer oral appliance outcomes.

I am embarrassed to say that I had not seen some of their previous research on this topic that had similar findings. This 2021 study compared DISE findings during the Esmarch maneuver in 20 patients with response to oral appliances and 50 without successful response. For study participants with mild to moderate obstructive sleep apnea, that study showed that 77% of oral appliance failures had a negative Esmarch maneuver (persistence of airway obstruction) during DISE, while only 25% of those with oral appliance success had a negative Esmarch maneuver!

I did not develop DISE but have worked with European colleagues (Drs. Nico de Vries and Winfried Hohenhorst) to provide its current name and to develop the VOTE Classification that is used to describe DISE findings. I have been fortunate to work with so many amazing colleagues to identify scientifically the key findings that are associated with surgical outcomes, including for Upper Airway Stimulation. While I always emphasize the need to perform research before relying solely on gut instincts, I am so glad to see that these studies have confirmed exactly what colleagues who came before me observed in their clinical practice and shared in scientific conferences. We are clearly indebted to those who undertake the heavy lifting of performing studies like these oral appliance investigations, but it is reassuring that the gut instincts were pretty much entirely correct.