By Steve Spencer
The American Medical Association estimates that obstructive sleep apnea (OSA) affects up to 30 million people. The condition, in which a person’s airway completely or partially closes during the night, can lead to a number of comorbidities. Poor sleep may be associated with an increase in insulin resistance, a precursor of diabetes. And because people with sleep apnea get less oxygen, it can elevate the possibility of heart attacks or stroke, as well as potential neurocognitive deficits.
The gold standard for treating OSA is continuous positive airway pressure (CPAP) in which the patient wears a mask that is connected through a hose to a motorized machine that delivers a continuous stream of pressurized air that acts like a stent to keep the airway open.
The problem is that although the CPAP works well, compliance is very low. A study of over 20 years of data shows that, even with advances in the CPAP like quieter pumps and softer masks, only around 30 to 50 percent of patients use the machine regularly, if at all.
“I’ve had patients who don’t wear their CPAP for a number of reasons,” said John Stafford, MD with ENT Associates of Alabama. “Some can’t wear it because of claustrophobia, while others are affected by PTSD. Sometimes people fall asleep before they’ve had a chance to put it on. And people might not take it when they go out of town. CPAP tolerance is so low that technical compliance for insurance purposes means that the patient is using it at least four days a week for four hours a night. That's very low.”
Unfortunately, there was no effective alternative for CPAP until the Inspire was introduced a few years ago. Currently, potential candidates for Inspire are patients who have moderate to severe OSA shown on a sleep study within the last two years, have a BMI of less than 35 for Medicare or 32 for private insurance, and cannot tolerate CPAP.
In order to see if patients who fit within these parameters are candidate for the Inspire, Stafford and the team at ENT Associates perform a drug induced sleep endoscopy in which the patient is given anesthesia to achieve a level of sedation that is similar to natural sleep. “At that time, I use a scope camera to examine their airway,” Stafford said. “With sleep apnea, your airway can close either by the tongue falling back to cause the blockage or by the sides collapsing. The tongue falling back, which we call an anterior to posterior collapse, is the type that is best suited for Inspire. The device stimulates the hypoglossal nerve during sleep, which keeps the tongue in a non-obstructive position.”
The Inspire is implanted during an outpatient surgery that usually lasts two to three hours. It consists of a small impulse generator that is implanted beneath the clavicle, along with a tunneled breathing sensing lead placed between the external and intercostal muscles, and a tunneled stimulation lead attached to the branch of the hypoglossal nerve that produces tongue protrusion.
“Originally this was performed as a surgery with three incisions, but as of this year we perform this through two incisions: one on the right neck and one of the right chest,” Stafford said. “The chest location holds the device and the neck incision is where the hypoglossal nerve is located. We dissect the hypoglossal to identify only the branches of the nerve that help keep the airway open. Then we place the stimulation lead around this portion of the nerve. We can test the device in real time and verify that the desired tongue motion has been achieved. While the device is immediately functional, the patient usually won’t fully activate it for use until about one month after surgery to allow for healing.”
The patient can turn on the therapy on before they go to sleep and turn it off when they wake up. They can also pause the therapy, if needed. Typically, patients feel a tingling sensation or mild contraction in their tongue muscles. The stimulation should not be painful or uncomfortable and the level is adjustable.
“I've had patients who had difficulty wearing their CPAP, and once they started on inspire, they’ve told me they couldn't be happier,” Stafford said. “They have restorative sleep. They wake up in the morning feeling much better than they’ve felt in years. It's great to finally be able to help those patients.