New research is showing that obstructive sleep apnea is more complicated than thought initially.
Upper airway patency during periods of sleep is determined by the activity of a small muscle called the genioglossus muscle. What’s significant about this finding is that it has led to a revolutionary new approach to treatment for sleep apnea that functions by stimulating the nerve connected to this muscle.
The common term for hypoglossal nerve stimulation therapy is Inspire. Named after the company that designed it, Inspire was approved as an official sleep apnea treatment by the FDA in 2014.
The Inspire Upper Airway Stimulation System
How It Works
Inspire works by affecting internal body function while you sleep.
The device is placed internally through an outpatient procedure and is equipped with an external remote. When you go to sleep, you simply turn the device on. It’s designed to open your airway and allow you to breathe normally throughout the night.
The upper airway stimulation system contains a small generator that releases electrical pulses. It’s placed right underneath the clavicle, or collarbone, between rib muscles with an electrical lead that attaches to the hypoglossal nerve.
The hypoglossal nerve is responsible for contractions of the genioglossus muscle mentioned earlier. Since this muscle determines whether the airway remains open or closed, controlling it externally is thought to keep the airway permanently open.
When the device is turned on, the generator lead detects inspiration. When this occurs, an impulse sends a signal to the hypoglossal nerve, resulting in forward placement of the tongue and opening of the airway.
This prevents the airway from being blocked upon exhalation, which is what occurs during periods of sleep apnea.
Candidates for Inspire Therapy
At present, patients must meet a specific set of requirements to be considered for Inspire therapy.
While the insertion of the device is a minor procedure, it does require an anesthetic, so there is some risk involved. Because of this, your doctor will need to determine whether you are a candidate for the device.
- 22 years or older in age
- A diagnosis of moderate to severe obstructive sleep apnea, defined as 15 to 65 apneic events per hour
- Body mass index below 33 kg/m2
- Difficulty with CPAP treatment or CPAP treatment is not successful
- No significant co-morbid medical diagnoses such as neuromuscular disease, nerve palsy, severe cardiac disease, or an active psychiatric diagnosis
- No obvious anatomic airway anomalies, including malformed tonsils and adenoids
- Full sleep endoscopy is required before being approved for an Inspire device implantation
Children, patients with mild sleep apnea symptoms, and obese patients are not currently considered for the Inspire device.
The rate of serious adverse events during or after implantation of the Inspire generator occurs in less than two percent of patients.
The majority of these events are related to the complications of the surgery itself rather than the device. Because Inspire requir an anesthetic, there is always a small risk of cardiovascular or respiratory collapse during the procedure, but this is extremely rare.
The qualification criteria exclude patients who would be at severe risk of a negative outcome.
Non-serious side effects of Inspire include temporary discomfort or pain at incision sites and tongue soreness or weakness due to nerve stimulation. The tongue discomfort improves over time once you become acclimatized to using the device.
Occasionally the device causes over-stimulation of the hypoglossal nerve and requires recalibration, but this is easily completed without any invasive procedures.
The New England Journal of Medicine published the STAR trial in 2014, which is considered the pivotal study outlining the success of Stimulation Therapy for Apnea Reduction (STAR).
One hundred twenty-six patients with obstructive sleep apnea were included in the study. All of them had difficulty maintaining positive airway pressure with CPAP treatment.
Results of the STAR trial showed a 68 percent reduction in sleep apnea events, from an average of 29.3 events an hour without treatment to an average of 9 events an hour with Inspire.
This success remained the same over a 12 month period. 66% of patients had a reduction of at least 50% in symptoms and less than 20 apneic events per hour. The reduction in the number of episodes was accompanied by a reduction in daytime fatigue and other functional measures of sleep quality.
There is a significant amount of testimonial evidence for Inspire’s success in treating sleep apnea.
- 90% of partners report reduced or no snoring after using Inspire.
- 94% of patients say they are satisfied with Inspire.
- 96% of patients say that Inspire treatment works better than CPAP and would recommend it to other sleep apnea sufferers.
Patients are required to follow up with their physician one month after the device implantation procedure to determine both the success of treatment and whether the device needs recalibration.
It is advised that Inspire be used on a nightly basis as soon as it’s inserted. The range of nerve stimulation can be adjusted on the remote, so patients will have to self-titrate the level over the first month to reach maximum stimulation.
Hours of use data and stimulation levels are stored on the remote for retrieval at follow-up appointments.
Inspire Vs. Other Sleep Apnea Treatments
Now that you understand how Inspire works, what’s the difference between Inspire and other traditional treatment methods?
CPAP is the most well-known treatment for sleep apnea. Like Inspire, it uses Continuous Positive Airway Pressure through a pump and face mask to keep the airway open at night. It’s one of the most effective treatments available, but most patients stop using it within the first 12 months.
The reason patients stop using CPAP is that they find the mask uncomfortable, experience uncomfortable side effects, and the pump irritates both them and their partners with its vibrating noise.
Inspire treatment is designed for those patients who aren’t successful with CPAP treatment. It has no mask and external pump, so it’s both quiet and invisible.
Inspire appears to be a very successful, viable treatment option for individuals who suffer from sleep apnea and have had little success with traditional treatment.
It is a safe option, given that there are strict criteria that must be met to qualify for the device. If you are eligible for this treatment and struggling to use a CPAP, Inspire is definitely worth considering.