Inspire implant for sleep apnea: what it is and how it works
The Inspire implant is a nerve stimulator, placed in an outpatient operation, that treats moderate to severe obstructive sleep apnea with no mask or hose. It stimulates the hypoglossal nerve, which moves your tongue, in time with your breathing: as you breathe in, the tongue moves forward and the airway behind it stays open. A handheld remote turns it on at bedtime. It is for adults who could not make CPAP work and whose airway anatomy suits it.
On this page
I have performed more than 600 Inspire implants. This page is the short version; my complete Inspire guide goes deeper on every part of it.
What is the Inspire implant?
Inspire is a hypoglossal nerve stimulator: an implanted device that treats obstructive sleep apnea by keeping the tongue from falling back into the throat during sleep. The FDA approved it in 2014, the first device of its kind, and it stimulates the nerve on one side, usually the right.[1] Nothing in the throat is cut or removed. It treats the apnea only while it is on, so it becomes part of every night, much as CPAP would be.
Inspire at a glance
| Question | Inspire |
|---|---|
| What it treats | Moderate to severe obstructive sleep apnea. It does not treat central sleep apnea. |
| Who qualifies | Usually adults 22 or older with an AHI of 15 to 100 for whom CPAP has not worked (full criteria below) |
| What is implanted | Inspire V: a generator below the collarbone, with the breathing sensor built in, and a stimulation lead with a cuff on the nerve. A handheld remote turns it on and off. |
| Incisions | Two: one in the upper right neck and one just below the collarbone |
| Battery | Sealed, never recharged; about 10 to 11 years on average, then the generator is replaced in an outpatient operation[2] |
| When it is turned on | At an office visit about one month after surgery; the strength is then raised about once a week |
| Follow-up sleep study | Month 3 or 4 after surgery, in a sleep lab or at home |
| MRI | Inspire IV and V: full-body MRI at 1.5 and 3 tesla under specific scan conditions. The oldest model, 3024, cannot have an MRI.[1] |
Candidacy and MRI rows follow the FDA labeling;[1] the timing rows follow the instructions I give my own patients.
How does Inspire work for sleep apnea?
When you fall asleep, the muscles that hold your airway open relax, and in obstructive sleep apnea the tongue falls back and blocks the airway, again and again through the night. Inspire senses your breathing. With each breath in, it sends a mild pulse to the hypoglossal nerve and the tongue moves forward toward your teeth; with each breath out, the tongue relaxes. It does not wait for your breathing to stop. It keeps the airway open breath by breath.
What a night with Inspire looks like:
- At bedtime you press the remote. One pulse of tongue motion tells you the device is on. It then waits, about half an hour unless I program it differently, so you can fall asleep before stimulation starts.
- If you get up in the night, the pause button stops therapy for about 15 minutes, and then it resumes on its own.
- In the morning you press the remote again to turn it off. It is used every time you sleep, naps included.
- In the first weeks therapy starts at a low strength, and you step it up about once every 7 days. If a level feels too strong, you step back down and try again a few days later.
While you are awake, the pulses may not match your breathing; many people feel a steady rhythm, such as four seconds on and one second off. Once you are asleep and breathing regularly, the timing follows your breathing more closely.
Video: how the Inspire implant works
In this ten-minute video, I explain how the Inspire implant works, who is a candidate, and what surgery and recovery involve. The player loads only when you press play.
What does the Inspire device consist of?
The Inspire sleep apnea device has two implanted parts in its current model, Inspire V. The generator sits under the skin just below the collarbone; it holds the sealed battery and the breathing sensor. The stimulation lead runs from the generator, under the skin of the neck, to a small cuff around the branches of the hypoglossal nerve that push the tongue forward. Outside the body, a handheld remote turns therapy on and off.
Through Inspire IV there was a third part: a breathing-sensor wire, the sensing lead, placed between two ribs. Inspire V has no separate sensing lead; its breathing sensor is built into the generator.[3] Diagrams that show a wire along the ribs describe the earlier hardware. The part that moves the tongue, the stimulation lead and its cuff, is the same as before.
Who is a candidate for Inspire?
Most Inspire candidates are adults with moderate to severe obstructive sleep apnea for whom CPAP has failed or could not be tolerated, whose weight is within the label and insurance limits, and whose airway collapses in a pattern that moving the tongue can open. Two tests settle it: a recent sleep study, and drug-induced sleep endoscopy (DISE), in which a thin camera looks at your airway for 15 to 20 minutes while you are lightly sedated.
- Apnea–hypopnea index (AHI), how many times an hour your breathing stops or turns shallow: 15 to 100 on the FDA label; Medicare uses 15 to 65.
- CPAP has not worked after a serious attempt: you cannot tolerate it, or it has not controlled your apnea.
- Mostly obstructive events: central and mixed apneas under 25% of the total.
- Body mass index (BMI) up to 40 in the FDA labeling; Medicare requires under 35, and some commercial plans stop at 32.
- No complete concentric collapse of the soft palate on DISE. When the palate closes from all sides at once, moving the tongue forward tends not to open it.
- Age 22 or older; ages 18 to 21 only in specific circumstances.[1]
Insurers’ written criteria are often stricter than the label. The candidacy section of my Inspire guide has the full checklist.
Does Inspire work?
For most patients, yes, though it treats sleep apnea rather than curing it. In STAR, the trial behind FDA approval, 83 of 126 patients (66%) reached the standard definition of success at one year: their breathing events fell by half or more, to fewer than 20 an hour. The median AHI went from 29.3 to 9.0. About a third did not reach that bar, and a small number get little benefit.[4]
- At five years, counting all 126 patients, 63% still met the definition, and 90% of bed partners of those still in follow-up reported soft or no snoring.[5]
- In routine practice (the ADHERE registry), the median AHI dropped from 34 to 7 at roughly one year, and 81% halved it and ended at 20 or lower.[6]
- In my own 111 patients, the average AHI went from 32.8 to 10.4; 77.5% reached a stricter bar, ending under 15 rather than under 20.[7]
The number depends on how it is measured: in 61 patients tested both ways, a titration study in a sleep lab gave a success rate of 80% and an all-night home study gave 46%.[8] I measure results with all-night home studies wherever I can. If the first follow-up study still shows significant apnea, which happens in up to 30% of cases, I adjust the settings, often during an awake endoscopy in the office, and repeat the study. My page on the Inspire success rate has the full breakdown.
All of these results come from systems implanted before Inspire V. The stimulation lead and the way it moves the tongue are unchanged, so they apply today; published outcome studies have not yet caught up with the newest hardware.
What is Inspire surgery like?
Inspire surgery is an outpatient operation under general anesthesia: about two hours in the operating room in my practice, one hour of it the operation itself, through two incisions in the upper right neck and just below the collarbone. I test the device before you wake up, but it stays switched off until an activation visit about a month later. Most people plan on two weeks off work. My printable post-op instructions cover recovery week by week, and my step-by-step guide to Inspire surgery covers the operation itself.
Is the Inspire implant safe?
Serious problems are uncommon, and most side effects pass: soreness at the two incisions, swelling under the jaw that can look like a double chin for two to four weeks, and stimulation that feels odd for the first nights after it is turned on. In the pivotal trial, fewer than 2% of patients had a serious procedure-related event in the first year.[4] When I compared 1,014 Inspire patients with 1,014 matched patients who had traditional palate surgery, 2.3% of the Inspire group had a complication within 90 days, against 20.1%.[9]
These figures come from implants made before Inspire V, which also had a sensor wire between the ribs. The neck incision, the chest pocket and the stimulation lead are the same today, so the risks below, including the removal rate, carry over; the problems that came from the rib wire do not.
- Bleeding at the chest pocket: about 1% in my experience.
- Infection: around or under 1%, but the device sometimes has to be removed when it happens.
- Tongue soreness, and temporary weakness of the tongue or lower lip; permanent weakness is very rare.
- Neck tightness if the connecting wire scars in place; the neck rolls I prescribe for four weeks help prevent it.
- Removal: about 2.7% of patients within three years in the largest real-world analysis.[10]
A collapsed lung, which still appears on older lists, was one of those rib-wire problems. I go through each risk, with the published numbers, on my Inspire side effects and risks page.
Inspire vs other options
If CPAP is working for you, stay with it: used all night, it remains the most effective, safest and cheapest treatment available, and Inspire vs CPAP compares the two. If it has not, start with what it means to fail CPAP. Inspire is one of two FDA-approved hypoglossal nerve stimulators; the other, Genio, stimulates both sides through one incision under the chin and is powered each night by a chip on an adhesive patch. I compare them in Inspire vs Genio, and my overview of sleep apnea implants covers both.