DISCLAIMER: I am a consultant for Nyxoah, who manufactures a technology mentioned in this blog post.

Inspire Medical Systems’ Upper Airway Stimulation is the only FDA-approved treatment of obstructive sleep apnea based on stimulation of the nerve that controls tongue movement (hypoglossal nerve). Based on their successes, a number of other technologies are in clinical trials, including Livanova’s aura6000 and Nyxoah’s Genio. We have led multiple research studies examining outcomes of Inspire treatment. These include a major study showing that specific findings on physical examination and the drug-induced sleep endoscopy evaluation required before surgery are associated with resuts of Inspire therapy.

The limitation is that using these examinations, at best, provides reassurance that a patient would have a roughly 80% of achieving the results that we would consider a success. Other patient subgroups have a figure that is as low as 60%. What would be a major step forward would be a test that would provide a trial run of hypoglossal nerve stimulation before a patient commits to undergoing surgical implantation of the device, with its costs, risks, and other considerations.

Dipping a toe into the water

What would be ideal would be a tryout of hypoglossal nerve stimulation to evaluate whether it would work well for a patient before committing to full surgical implantation. While not perfect, intriguing research suggests that this may be possible at some point in the future. The work is based on the ability to stimulate the hypoglossal nerve with placement of an electrode through the skin to test the benefits for a short period of time.

In January at the International Surgical Sleep Society meeting in Wollongong, Australia, Danny Eckert, PhD from the Neuroscience Research Australia presented their work showing that hypoglossal nerve stimulation using an electrode placed through the skin improved airflow. David Kent, MD from Vanderbilt University has just published his work showing that hypoglossal nerve stimulation using an electrode placed through the skin can improve airway collapsibility, as measured during drug-induced sleep endoscopy. Importantly, in both of their work, there was quite a bit of variation in benefits seen with hypoglossal nerve stimulation, which is actually reassuring because we see the same kind of variation in results of surgery (even if we try to reduce that variation in our examination before surgery to identify the best candidates and provide informed decision making). Of note, both of these studies were supported by Invicta Medical, a company that also provided the implant used in the research.

Sign me up!

This is clearly not ready for use outside of research studies just yet. There are some important limitations to these studies and their direct clinical use. First, the evaluation of results in these studies has only been for very short periods of time, as it is simply not feasible with current technologies to have an electrode with a wire extending through the skin outside the body. It would theoretically be possible to perform a similar trial with a small stimulator placed through a large needle without a full surgical incision. Stimulators like this do exist, and they could be left in place to operate for a period of time but not likely forever because the body tends to displace them over time. A longer trial period would be nice, but even a short evaluation could be better than none at all.

It remains unclear whether there will be a trial of hypoglossal stimulation (or potentially other methods of nerve stimulation) available – or required – before surgical implantation of a system. However, these studies raise the potential of what could be a major step forward to predicting outcomes of surgery. I tell patients often that I chose to pursue a career in sleep surgery because the results were not very good or predictable. We have made major strides as a field, but there seems to be always more work to do.