How does a small structure with a funny name — the epiglottis — contribute to obstructive sleep apnea? What can be done to treat the epiglottis?

My colleague at UC San Francisco, Dr. Andrew Goldberg, came up with a title for a lecture I have given (and which I have used for this blog post), based on the notion that the epiglottis protects us from danger but also can be a primary cause of obstructive sleep apnea. The epiglottis (see illustration) is a piece of cartilage, covered with mucosa (lining of the throat), that sits in the lower part of the throat. Its major role is to assist in swallowing, as the muscles of the throat push the epiglottis backwards (in addition to other throat movements) to cover the voice box (larynx) during swallowing and prevent food and liquid from entering the lungs.

 

But it is not all good for the epiglottis. Based on my research utilizing drug-induced sleep endoscopy and the work of others, it is estimated that about 16% of patients considering surgery for sleep apnea appear to have their epiglottis substantially either fall backwards (the more-common pattern) or fold side-to-side during sleep. Both of these can narrow the space for breathing and contribute to sleep apnea, a key issue that we might want to address with surgery. For patients with sleep apnea and the physicians who treat them, there are two questions:

• What is the best way to determine if the epiglottis is playing a role?
• How do we treat the epiglottis, including with sleep apnea surgery?

Identifying the epiglottis as an important factor in sleep apnea

There are many evaluation techniques for patients with snoring and obstructive sleep apnea. I have completed a number of studies related to drug-induced sleep endoscopy in sleep apnea because I think it offers unique insight into what is causing blockage of breathing during sleep for a specific patient. When done carefully, this evaluation may reproduce a sleep-like state that allows us to examine what structures in the throat may be contributing to sleep apnea and therefore need to be addressed. This is very different from most other techniques, which are performed with patients awake. Identifying the role of the epiglottis may represent an important role for sleep endoscopy, as other sleep apnea evaluation techniques are unable to determine this.

Because drug-induced sleep endoscopy has some risks and costs, many of us have tried to determine other ways to obtain the information we get from sleep endoscopy without the risks and costs.  I have noticed two things in patients where the epiglottis plays an important role. One is that these patients come to see me because they cannot tolerate CPAP, and some of them may get a sensation of choking with their continuous positive airway pressure (CPAP) therapy. This choking sensation is not only dramatic and disturbing but also very different from other reasons for being unable to tolerate CPAP. This may occur because CPAP could, at least theoretically, be pushing the epiglottis backwards to create a complete seal in the throat that cannot be relieved by higher CPAP pressures. This is very different from blockage due to other structures like the soft palate or tongue, where blockage is relieved when the CPAP pressure rises. In fact, a recent blog post highlighted our drug-induced sleep endoscopy research suggesting that CPAP actually can push the epiglottis backwards to block breathing as CPAP pressures increase in some obstructive sleep apnea patients. This is actually one of the updates on this blog post, as compared to the previous similar post from 2013.

The other findings common to many patients with an epiglottis role come from the fiberoptic telescope that I use to examine patients in the office. The epiglottis can often be sitting further back, almost positioned against the back of the throat. Often there is also a curve to the upper half of the epiglottis, almost as if it is bent forward (towards the tongue) over time, as the epiglottis is repeatedly falling back against the back of the throat. A second finding was confirmed in the study of my patients; epiglottis-related obstruction during drug-induced sleep endoscopy was more common in those with the epiglottis displaced backwards (towards the back of the throat), separate from the tongue, during flexible telescope examination while awake. Relying on these findings have not replaced drug-induced sleep endoscopy in my practice, but they can make me suspicious about a role for the epiglottis.

How to treat the epiglottis with surgery

Once we suspect a role for the epiglottis, whether from drug-induced sleep endoscopy or some other evaluation, what should we do, considering the full array of options, including surgery?  As described above, increasing CPAP pressures may only make the problem worse.  Decreasing CPAP pressures also generally does not work, as there often needs to be enough pressure to open the breathing passages.  So we must look at alternatives that either address the sleep apnea alone or in combination with treatments like CPAP.  Behavioral changes like weight loss, avoiding sleep on one’s back, and eliminating alcohol intake within 3 hours of bedtime can help many patients, but they are not specifically targeted to the epiglottis.  Oral appliances move the lower jaw forward and can also be beneficial, even if they also do not address the epiglottis directly.  Although surgery is not the only option for these patients, it is the only category of treatment that can focus on the epiglottis.

Another update included in this post is the addition of a new type of epiglottis-focused surgery. There are now three major types of procedures that are directed more specifically at the epiglottis: removal of a portion (partial epiglottectomy), hyoid suspension, and using cauterization to keep the epiglottis in a forward position.

European colleagues have substantial experience with surgery incorporating removal of a portion of the epiglottis, an approach described on my epiglottis surgery page. However, the two major published studies (brief summaries here and here) of the procedure come from a collaboration between surgeons in New Jersey and Israel. They selected patients with one of the findings mentioned above (positioning of the epiglottis towards the back of the throat during awake physical examination in the office) and performed a somewhat-aggressive removal of part of the epiglottis. Their approach produced dramatic improvements, clearing up sleep apnea in almost 80% (21/27) of those in one study. In Europe, this was a popular approach for patients who have an epiglottis contributing to sleep apnea. Although my European sleep apnea surgery colleagues have reported good results, they have not published studies reporting results with this procedure on its own. Personally, I have been concerned about being so aggressive because of the risks of having food or liquid fall into the lungs when attempting to swallowing, and my results for this type of surgery have not been as impressive as they discuss.

The hyoid suspension procedure treats the epiglottis differently.  The hyoid bone is a relatively thin, horseshoe-shaped bone in the neck.  The hyoid bone in humans is unique in that it can move.  A mobile hyoid bone appears to have been one of the evolutionary changes important in the development of speech, but it likely also contributes to our risks for developing sleep apnea (which is not seen in most animals, except for some dogs).  The hyoid bone is important because it has attachments to a number of other structures, including the epiglottis (through the hyoepiglottic ligament) and muscles that are next to or surround the throat (including the middle pharyngeal constrictor). During sleep, muscles relax, and the hyoid bone is free to move towards the back of the throat, allowing the structures attached to it to fall into the throat and block breathing. The hyoid suspension involves pulling the hyoid bone forward and using stitches to secure the hyoid bone either to the top part of the Adam’s apple (thyroid cartilage) in a slightly-downward direction or to the lower part of the lower jaw (mandible). These hyoid suspension techniques have not been compared side by side, but years ago we completed a study in a small number of human cadavers that compared pulling the hyoid bone forward in different directions. This study suggested that the best direction may be directly forward, closer to the suspension technique to the thyroid cartilage.  This is the hyoid suspension technique that I use in my own practice.

Over the past 5 years or so, I have utilized the epiglottis stiffening operation, a technique relying on cauterization to move the epiglottis forward. This procedure was developed by Italian colleagues, reporting impressive results for those with epiglottis-related obstruction. By cauterizing the front of the epiglottis, this procedure relies on the body’s natural healing process to scar the cauterized area and bring the epiglottis forward. The idea underlying this surgery is that the epiglottis will then not be able to fall backwards to block breathing and cause sleep apnea. I have recently had some cases where the epiglottis does not come forward enough after this procedure, so I am considering placement of sutures through the epiglottis to hold it forward during the healing process. This additional step is called epiglottopexy, and one my close colleagues at UCLA, Dr. Sohit Kanotra, has published research sharing his extensive experience and expertise with epiglottopexy. While this has been performed in children, Dr. Kanotra has performed this in children and adults, with subtle changes in technique and similar good results.

What do I do if I am worried about the epiglottis?

I believe strongly that the epiglottis plays an important role for many patients with obstructive sleep apnea, whether or not they are considering surgical treatment.  There are clues from the medical history and physical examination that make me more or less concerned about this. However, the main way I check for the role of the epiglottis is with drug-induced sleep endoscopy.  I have had success treating these patients using multiple epiglottis-focused techniques. In speaking with my patients, we combine specific findings from their examination as well as their preferences (these procedures have slightly different risks and characteristics) to develop a joint decision about the best option for them.