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Hypoglossal Nerve Stimulator Surgery, Part 1: Candidacy, Technique & Device Limitations

Author Taylor Spurgeon-Hess covers Hypoglossal Nerve Stimulator Surgery, Part 1: Candidacy, Technique & Device Limitations on BackTable ENT

Taylor Spurgeon-Hess • Apr 12, 2022 • 49 hits

In patients with obstructive sleep apnea (OSA) that do not benefit from treatment with a CPAP machine, surgically placing a hypoglossal nerve stimulator may help to reduce OSA occurrence and provide significant relief. The nerve stimulator functions by gently stimulating the base of the tongue to move forward and tighten with each breath as the patient sleeps. This decreases both snoring and airway obstruction. While still a relatively new procedure, hypoglossal nerve stimulator surgery continues to increase in popularity as patient’s continue to report positive outcomes. Learn more about patient candidacy, surgical approach, and limitations of current hypoglossal nerve stimulator devices.

This article features excerpts from the BackTable ENT Podcast. We’ve provided the highlight reel in this article, and you can listen to the full podcast below.

The BackTable ENT Brief

• Ideal candidates for hypoglossal nerve stimulator surgery have moderate obstructive sleep apnea, an AHI of 15 to 65, a BMI of less than 35, and have failed to find relief with a CPAP machine.

• Surgery involves two incisions: one at the chest and another under the mandible. The surgeon inserts the deceive processor into the chest and places a stimulator lead on the hypoglossal nerve.

• Extra caution must be taken when creating the submandibular incision, in order to avoid injuring the marginal mandibular branch of the facial nerve.

• After surgery, patients may not be able to receive an MRI in the right chest or upper extremity due to the device implantation. They can also expect to surgically replace the battery of the device every 11 years.

The backtable setup for a hypoglossal nerve stimulator surgery.

Image provided by Inspire Medical Systems, Inc.

Table of Contents

(1) Candidacy for Hypoglossal Nerve Stimulator Surgery

(2) Hypoglossal Nerve Stimulator Surgery Technique

(3) Limitations of Placing a Hypoglossal Nerve Stimulator

Candidacy for Hypoglossal Nerve Stimulator Surgery

While hypoglossal nerve stimulator surgery can provide significant relief of OSA, not all patients qualify as candidates. Ideally, an otolaryngologist would look for patients with at least moderate sleep apnea and an Apnea Hypopnea Index (AHI) of 15 to 65. The patient’s BMI should be less than 35, but some insurance companies may require even lower. Additionally, the patient must have failed CPAP and have a sleep study without signs of central or mixed apnea. Obstructive apnea can be addressed with a hypoglossal nerve stimulator because the underlying problem involves blockage of the airway, as opposed to central apnea, in which the problem is an issue with muscle signaling from the brain.

[Gopi Shah MD]
Okay. And so it's pulling the tongue forward. So what are the criteria now? Like who's a good candidate? Do they have already had to try C-PAP first a certain number of time? I think you'd mentioned a range of AHI, height, weight. Who are the people that kind of fit the potential?

[Matthew Hensler MD]
Fit the mold for it. Yeah. So again, you want to at least see moderate sleep apnea. So AHI over 15, we have implanted people over 65 and I think that's an important thing as we get into outcomes, that you have to consider like, what were the initial parameters and how did you get the outcomes for that? And then if you start implanting people with a super high AHI, you can't really have the same expectation that they're going to get as low afterwards. But, so generally it's been 15 to 65 was the AHI. And BMI. We like to see that less than 35. And that's variable too. Because it depends on their insurance. Some insurances require lower. Some really don't have any guidelines for that. But generally we want to see that they're not too overweight, when you're considering it.

And another really important piece to it is to make sure on their sleep study, that they're not having a lot of central apneas or mixed apneas. And so the difference there, obstructive is that your something's blocking off your airway, whereas central you're not trying to breathe. And so if you're not trying to breathe, it's not going to matter if you stimulate the base of tongue, you're not going to breathe. So you really don't want to implant anybody that's got central or mixed apnea greater than 25% of their sleep study. And the last thing is, as you mentioned, C-PAP so we really want to see that they've failed C-PAP because it is still the gold standard of managing sleep apnea. And it has great results if people use it regularly, but there are plenty of people who just don't tolerate use. Whether it's claustrophobia or they're swallowing air, or you could go on and on, or they're caught up in the inconvenience of using C-PAP. That's part of it. It's pretty rare that we'll implant somebody that hasn't tried C-PAP. I mean, I think there's a few situations where you could consider it, but it gets me back to that point where I say, I really try to talk people out of surgery sometimes because if C-PAP’s working, that's great. And I get it can be inconvenient, but it's still a device that's implanted in you. It's a battery there's limitations afterwards in terms of MRIs, whatnot. So just a lot of things to consider rather than just, I've got sleep apnea, C-PAP annoys me and I want to put this device in.

[Gopi Shah MD]
Yeah.

[Matthew Hensler MD]
Yeah. So those are the main criteria.

[Gopi Shah MD]
So in your practice, do you have them try C-PAP for like six months, three months? Do you feel like you kind of have a timeframe that you want them to at least keep trying? And do you work with your pulmonologist with that? Or how do you help that part of it?

[Matthew Hensler MD]
Yeah, we work pretty well with pulmonology. So often we'll at least try a month and they're able to look at the device and see how much they're using it. How long at night, how much adherence they're having to using the device. And you kind of take that all in perspective and really, it just boils down to if they've tried the C-PAP and they're just not doing well with it. If we get to that point of the discussion, that's when we just say, okay, you could consider the implant.

Listen to the Full Podcast

Hypoglossal Nerve Stimulation for Adult OSA with Dr. Matthew Hensler on the BackTable ENT Podcast)
Ep 51 Hypoglossal Nerve Stimulation for Adult OSA with Dr. Matthew Hensler
00:00 / 01:04

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Hypoglossal Nerve Stimulator Surgery Technique

Surgically, placing a hypoglossal nerve stimulator involves making two incisions, one in the chest and one in the submandibular area. Often this takes place on the right side of the body in order to stay away from the heart in case a pacemaker ever needs to be placed. The processor is placed in the chest with the sensor lead running down into the rib cage to sense breathing, and the stimulator lead running up to the hypoglossal nerve. The upper incision must be at least a finger breadth below the mandible in order to avoid injuring the marginal mandibular branch of the facial nerve. When dissecting on the hypoglossal nerve, surgeons often look for the “break point” in order to ensure the device stimulates both the inclusion and exclusion branches but not the retrusor branches.

[Matthew Hensler MD]
Sure. That's a great question because I think a lot of people hear what it is and then when they hear actually how it works, it's a little different. It's two incisions and you implant typically on the right because we reserved the left if somebody would need a pacemaker and we stay away from the heart. So you go on the right and you put a processor in the chest that has a battery and there's a sensor lead that feeds off of it, down into the rib cage so that it can sense when they’re breathing. And then there's a stimulator that runs, it's a little wire that kind of comes up the neck and there is a second incision kind of under the jawline. And that's how you place the stimulator lead on the hypoglossal nerve.

So once you're done with that, at night, when they go to sleep, they take a device that kind of looks like a mouse for a computer and you turn the device on and, you can change this, but after a certain period of time, it will begin working so that every time the patient breathes- so whenever it senses that there's chest wall, expansion or movement- that will gently stimulate the base of tongue to push forward and tighten up. So it's not just working when you snore, it's not just working when you have apneas, it's doing it with every single breath, it's pushing the tongue forward. And you can turn it on and off at night. If you wake up and you need to use the restroom or something, you can turn it off and turn it back on. But that's generally how it works.

[Gopi Shah MD]
So you described, two incisions, one in the chest and one kind of right, maybe submandibular area. Do you monitor the marg for that? Or do you just go below the gland or, is that a concern, how do you monitor?

[Matthew Hensler MD]
For sure. So it's really interesting you bring that up. I feel like in training, we're always taught two finger breadths below the mandible to avoid the marg. We avoid that nerve at all cost and the way that this was taught to implant, you end up making an incision a lot closer to the mandible. It's more like a finger breath because you kind of, you're trying to find the hyoid and you find the midline and you try to split the difference and kind of extend it back from there. So you end up being, I think, a little bit closer anatomically to the marg. I don't specifically monitor it during surgery, but you can see their mouth in view when you have them prepped out. So you're able to tell if you're getting stimulation or if you're getting close, I've never had anybody that's had marg weakness afterwards. Because I still, even though the incision is high, I still aim really low to get down on the bottom part of the submandibular gland, just so you're not close to it. And then you work your way up.

[Gopi Shah MD]
And then for the chest incision, are you below the pec and the nipple? Where is that? And are you going down to rib? Like, do you have to worry about pneumothorax? Like how does that work?

[Matthew Hensler MD]
So when I first started doing the procedure, it was three incisions and the one incision was a couple of finger breadths below the collarbone. So that was for the device. And then the sense lead was down kind of along like if you come down under their armpit and you come across just kind of like a bra line, it would sit down along the ribs there. So that was the third incision, but we really don't do that anymore because now you're placing the sense lead within that a higher incision. So it's two finger breadths below the collar bone. And you, once you've made a pocket for where the implant is going to sit, you just kind of go through pec major and you'd bluntly divide it until you're getting down to the intercostals and you try to find the nice plane between the internal and external intercostals. In training, look, I never was dissecting down onto the ribs. So initially it was always a very like, oh my gosh, we're near the lung, it's right through there. And, you're definitely cognizant of it. It's got some really, really good safe anatomy to get to that level. And you develop a pocket between the two muscles between the intercostals and you feed the sense lead there. So as you said, pneumothorax is one of the reported risks of the procedure. I personally, knock on wood, haven't been affected by it. And again, I think it's, you're just, you're smart when you get down to that point and you're delicate as you work between the muscles to avoid that complication. And we do a chest x-ray afterwards to make sure there's no issue with pneumothorax, especially.

[Gopi Shah MD]
Do you have any special landmarks or techniques to help you feel like your sensor is where it should be? How do you know?

[Matthew Hensler MD]
Well, when you're dissecting on the hypoglossal nerve, there are a couple little landmarks. Really the main one is, you're just looking for what we call it, the break point, where you can see these retrusive branches kind of extending up. And so we will use a nerve stimulator for that and kind of stimulate the inclusion branches and your exclusion branches. And you'll kind of tell when you'll isolate the nerve, maybe put a vessel loop around it to say, here's the branches we want to include. And then you use a little probe to stimulate them and make sure that your inclusion branches are stimulating well. And that you're not including any of the retrusor branches.

Limitations of Placing a Hypoglossal Nerve Stimulator

Before surgery, the otolaryngologist must counsel patients on the limitations of the nerve stimulator device related to its battery and concerns related to MRIs. Since the nerve stimulator contains metal, MRIs of the right upper chest or right upper extremity are contraindicated. Companies continue to release updated guidelines regarding the device and MRIs, but patients should be made aware upfront that limitations exist. The battery in the hypoglossal nerve stimulator lasts approximately 11 years and patients can expect to undergo outpatient surgery to replace the battery at some point.

[Gopi Shah MD]
Yeah, no, that's very helpful. In terms of, you had mentioned battery and MRI, how do you talk to patients about the battery and potential needs of MRI? What are the limitations?

[Matthew Hensler MD]
That's kind of a moving target I would say. The MRI indications, generally I tell people expect that you're not going to be able to get an MRI of the right chest or kind of right upper extremity kind of this area, because that's where the battery is going to be. Now there are, as the device continues to change, the companies continue to send out, here are the MRIs that are allowed or the regions that are allowed, but ultimately it's good to make sure that people understand upfront there may be limitations. We haven't done any like removals of a device so that somebody could get an MRI that we haven't ever run into that. The battery itself lasts currently about 11 years. So we tell people expect that in 11 years, if and when the battery is not working, you can do an outpatient surgery just to replace the processor with the battery.

[Gopi Shah MD]
And that's just your chest incision.

[Matthew Hensler MD]
Yeah. The high chest incision. Yep. Yep. So you just go through that and so we'll get to that point someday once you get there, but the device also continues to, like I said, it evolves a lot in terms of what battery it is, what the MRI compatibility is. So it's just good to make sure that patients ask about that and see what the most recent guidelines are and limitations.

Podcast Contributors

Dr. Matthew Hensler discusses Hypoglossal Nerve Stimulation for Adult OSA on the BackTable 51 Podcast

Dr. Matthew Hensler

Dr. Matthew Hensler is a practicing otolaryngologist in Cincinnati, Ohio.

Dr. Gopi Shah discusses Hypoglossal Nerve Stimulation for Adult OSA on the BackTable 51 Podcast

Dr. Gopi Shah

Dr. Gopi Shah is a practicing ENT at UT Southwestern Medical Center in Dallas, TX.

Cite This Podcast

BackTable, LLC (Producer). (2022, March 1). Ep. 51 – Hypoglossal Nerve Stimulation for Adult OSA [Audio podcast]. Retrieved from https://www.backtable.com

Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.

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Hypoglossal Nerve Stimulation for Adult OSA with Dr. Matthew Hensler on the BackTable ENT Podcast)

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An illustration depicting the placement of a hypoglossal nerve stimulator.

Hypoglossal Nerve Stimulator Surgery, Part 2: Postoperative Care, Device Settings & Side Effects

Topics

Hypoglossal Nerve Stimulation Procedure Prep
Obstructive Sleep Apnea (OSA) Condition Overview

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