The standard treatment for people with moderate to severe obstructive sleep apnea is a mask worn at night that helps them breathe without interruption. The mask is unwieldy and uncomfortable, however; one study found that 46 per cent to 83 per cent of patients with obstructive sleep apnea do not wear it diligently.
Now scientists may have found an alternative, at least for some patients: a pacemaker-like device implanted in the chest that stimulates a nerve in the jaw, helping to keep part of the upper airway open. The device, called a neurostimulator, helped reduce breathing interruptions and raise blood oxygen levels in about two-thirds of sleep apnea patients participating in a trial, researchers reported on Wednesday in The New England Journal of Medicine.
“This is a new paradigm of surgical treatment that seems to effectively control obstructive sleep apnea in selected patients,” said Dr Sean M. Caples, a sleep specialist in the division of pulmonary and critical care medicine at Mayo Clinic in Rochester, Minnesota. “It’s very exciting.”
Still, Dr Caples, who was not involved in the new study, noted that “a third of patients were not improved when all was said and done,” even though they were chosen because they were seen as likely to benefit.
The new trial was funded by the maker of the device, Inspire Medical Systems.
At 22 sites internationally, in 126 patients, doctors surgically implanted a remote-controlled neurostimulator that, activated at night, sends regular electric impulses to a nerve inside the jaw. The impulses cause the tongue to move forward during inhalation, opening the airway.
Patients experienced a decline in breathing pauses after using the device for a year, to 9 per hour on average, from 29.3 episodes per hour. The number of dangerous drops in blood oxygen levels also declined, to 7.4 per hour on average, from 25.4 per hour.
There was no control group during this phase of the study, however, and other experts said that diet, exercise or other factors may have contributed to the reductions.
At a year, only two of 126 patients stopped using their upper airway stimulator at night, and 86 percent reported daily use. But sleep apnea worsened in about 20 patients using the device, though it is unclear why.
In the second phase of the study, 46 patients doing well with the stimulators after one year were randomly assigned to either continue with the therapy or have it withdrawn for a week. The therapy-continuation group had little change in the number of breathing pauses per hour or drops in blood oxygen levels. But in the patients from whom the stimulation therapy was withdrawn, the number of such breathing pauses increased sharply, to 25.8 per hour on average from 7.6 per hour. The episodes of blood oxygen level drops rose to 23 per hour on average, from 6 per hour.
“That rebound was compelling evidence that this device did something for their sleep apnea,” said Dr Christine H. Won, the medical director of the Yale Sleep Center.
An alternative therapy for patients who can’t or won’t use standard continuous positive airway pressure (CPAP) masks diligently would be “very valuable,” Dr Won said.
The neurostimulator is not yet approved by the Food and Drug Administration and may only benefit a subset of sleep apnea patients, including those with a body mass index of less than 32 and people whose obstructions stem from airway collapse behind their tongues. Only patients who could not or would not use mask therapy participated.
Less than 2 per cent of study participants experienced serious adverse events. Still, more than half reported discomfort from stimulation, tongue abrasion, incision discomfort and other issues.
After her chin incision became inflamed after implantation of the neurostimulator in 2011, Jackie Kopplin, 45, who runs a housecleaning business in Coon Rapids, Minnesota, was “blown up like a basketball” and in pain for six weeks. “I was regretting it at first,” she said.
But she now sleeps eight to nine hours at night, is not bothered by the tongue thrusting, and no longer dozes off while driving.
As long as she remembers to turn on the stimulator nightly, Kopplin said, “I wake up and I have energy to make it through the whole day.”
- By Catherine Saint Louis