Nashville, TN was the site of both the 2023 International Surgical Sleep Society (ISSS) Educational Symposium and American Academy of Otolaryngology – Head and Neck Surgery Foundation Annual Meeting. It is always wonderful to see colleagues and long-time friends. However, I wanted to take the chance to share some of what I found to be the most interesting scientific presentations, in no particular order.
Multiple talks and sessions focused on obtaining optimal results with treating obstructive sleep apnea with hypoglossal nerve stimulation treatment. At the ISSS meeting, Ryan Soose, MD from the University of Pittsburgh presented his fascinating work examining usage patterns for patients implanted with Inspire Upper Airway Stimulation system. Using objective data from 2098 patients in the Inspire Cloud database, their team showed that there are 3 basic clusters of usage patterns: nightly use through the entire night, good use with some missing days, and variable use with missing days with or without frequent pauses throughout the night. He eloquently placed this within the context of a proposed Usage, Symptoms, and Apnea Metrics framework for examining those who do not respond well to Inspire therapy, and this was all compelling. It particularly resonated because of more attention (at the meeting and in caring for patients) being devoted to helping those who do not achieve success with Inspire therapy. Previous published research (also presented at the ISSS meeting) from Tom Kaffenberger, MD (now also at the University of Pittsburgh) and Mau Boon, MD and Colin Huntley, MD at Thomas Jefferson University showed that those with insomnia used their Inspire therapy an average of 4.9 hours/night, while those without insomnia used it 5.8 hours/night. It is worth noting that a presentation at the AAO-HNS meeting from the team at the University of Cincinnati including Stacey Ishman, MD that relied on 1400 study participants in the Inspire ADHERE Registry suggested that those with insomnia (based on the Insomnia Severity Index) actually had greater use. Also at the AAO-HNS meeting, I moderated an entire session about those who do not respond well to this treatment, and my talk focused on those with substantial insomnia (primarily difficulty initiating or maintaining sleep), especially with highly-variable times to fall asleep or fall back to sleep once they awaken. I discussed the reasons why this is such a major issue for the ability of patients to use Inspire therapy as much as they would like. In fact, I have removed the Inspire implant in a fair number of patients in this category who simply could not tolerate Inspire therapy. This is the reason that I consider substantial insomnia to be a reason that someone is not eligible for nerve stimulation treatment.
Abhay Sharma, MD from the University of South Florida presented work done with Tucker Woodson, MD at the Medical College of Wisconsin. They examined 124 individuals with obstructive sleep apnea and showed that tongue tie (ankyloglossia) was not associated with tongue strength (anterior or posterior), tongue muscle endurance. Furthermore, there was no association between the severity of obstructive sleep apnea (measured by the apnea-hypopnea index, or AHI) and tongue range of motion or tongue strength. This is just one more study to suggest that there is no evidence to support treatments like frenuloplasty or frenectomy in the treatment of adults with obstructive sleep apnea.
Chihun (Jim) Han, MD from the Thomas Jefferson University sleep surgery team examined results from the Inspire ADHERE Registry and found that individuals who lost substantial weight (at least 2 kg/m2 in body mass index, or BMI) had notably better outcomes than those who had stable weight or gained weight. Later at the AAO-HNS meeting, Daniel Jira, MD shared the experience over 3 years following implant of hypoglossal nerve stimulation at the Technical University of Munich, showing a small reduction in BMI in non-responders and a slightly-greater increase in BMI in nonresponders. In both studies, it was not possible to determine the direction of causation: whether those with better outcomes felt better and were more able to lose weight or whether the weight loss was a key factor causing the weight loss. This is another example showing how a combination of approaches to treat obstructive sleep apnea can enhance results.
Phil Huyett, MD from Mass Eye and Ear completed research with our team involving 343 study participants from 10 centers around the world, showing that findings of drug-induced sleep endoscopy are associated with outcomes of Inspire treatment. This work showed how important it is to look at patient anatomy when discussing Inspire therapy with patients. One of the key findings that was discussed in detail at both meetings was the evidence that substantial collapse of the sides of the throat (oropharyngeal lateral walls) are associated with poorer outcomes (60% vs. 80% response rate). At the ISSS meeting, Dr. Huyett presented his early work in 15 study participants showing that adding tonsillectomy to Inspire may dramatically improve outcomes in those with this unfavorable pattern of collapse. He was appropriately cautious in interpreting results from his relatively-small group of patients, but it was so intriguing. I look forward to seeing results as he follows these individuals over time.
David Kent, MD from Vanderbilt University has done some pioneering work in nerve stimulation for treatment of obstructive sleep apnea. Specifically, his work in stimulation of a nerve branch from a structure called the ansa cervicalis has so many of us in the field excited (no pun intended). Yike Li, MD, PhD is a research faculty member working with Dr. Kent, and Dr. Li presented their work looking at the improvements in airflow and combined endoscopic evaluation. They showed that the addition of bilateral ansa cervicalis stimulation to bilateral hypoglossal nerve stimulation improved airflow dramatically, with the impact greater when the airflow was blocked by the soft palate, sides of the throat, and epiglottis, as compared to the tongue. The idea is that hypoglossal nerve stimulation treats the tongue well by moving it forward directly, with ansa cervicalis stimulation offering benefit for other patterns of blockage (where hypoglossal nerve stimulation can help but may not produce enough opening of the airway.
Jordan Weiner, MD from Phoenix presented results from the Inspire-funded PREDICTOR study that is focused on identifying whether we can avoid the need for drug-induced sleep endoscopy prior to implantation. This study is evaluating whether measurements of the width of the throat are associated with results of Inspire treatment and two of the worrisome findings from drug-induced sleep endoscopy: complete concentric collapse of the airway related to the soft palate and collapse of the sides of the throat. What they have found is that there is an association, with narrower throats more likely to have poorer outcomes and demonstrate these findings. However, there does not seem to be an obvious threshold effect, where a certain measurement would be highly likely to have or not to have these findings. For the time being, we as patients and surgeons still need to perform drug-induced sleep endoscopy.
At the AAO-HNS meeting, Ying-Shuo Hsu, MD from Taiwan spoke about machine learning interpretation of drug-induced sleep endoscopy videos. This fascinating but complicated and time-consuming work involved 10 study participants, video modification techniques including augmentation, and analysis with U-Net software. They focused on assessment of the soft palate showed promise. As they continue their work, they found that image quality, tonsils, and saliva can impact the ability of machine learning the performance of the system.
Emily Commesso, MD from Duke University presented work that she performed while pursuing her fellowship training in sleep surgery with our team at USC. She presented our experience with a rare complication of migration of the respiratory sensing lead of the Inspire system, specifically that we have had two patients with this complication 2-3 years after implantation, both of whom required surgery to treat this. Her research included review of the FDA’s MAUDE database that is based on mandatory reporting of adverse events for FDA-approved devices. Her work showed that there were 12 reported instances of migration of a sensing lead and that there were some typical signs and symptoms of this. Of note, this is a different type of issue than what has been a focus, the separation of the tip of the sensing lead that resulted in a redesign of the lead by Inspire Medical Systems.
Eric Thuler, MD, PhD shared research performed at the University of Pennsylvania that compared findings during drug-induced sleep endoscopy (specifically what they call pharyngeal opening pressure) and findings from CT scans of the neck. In 169 study participants, they found that this measure of collapsibility was associated with the space for breathing behind the soft palate (minimum cross-sectional airway and retropalatal airway volume) and not the size of the tongue or the tissues on the side of the throat.
Overall, there was so much interesting research presented at these two meetings. We only have a short break until the International Surgical Sleep Society meeting in January 2024 in Wollongong, Australia. I expect that the research presented there will come more from international colleagues, and I look forward to learning more!