New treatment helps combat
chronic sleep disorder
BY KRISTA CONGER
Stanford, May 17 -- The noisy sleeping habits of some
people may be more than just a nuisance to their families
and bed partners. The choking, gasping sounds that
accompany the slumber of people suffering from
obstructive sleep apnea are symptoms of what could be a
life-threatening medical condition. Stanford researchers
have introduced a technology that could help solve the
problem by shrinking the excess tissues that obstruct
breathing when the airway relaxes during sleep. The
nearly painless outpatient procedure takes about 30 to 45
minutes to perform and, after being monitored overnight,
patients can return to their normal activities.
"This is a
breakthrough in the treatment of sleep apnea," said
Nelson Powell, MD, co-director of the Stanford University
Sleep Disorders Center, who conducted a recent study on
the procedure. "We haven't had a new efficacious
treatment with a scientific basis in years," he
said.
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The researchers used
radiofrequency energy to heat internal tissue in the base
of the tongue to about 80š C. The heat-induced
lesion is reabsorbed by the body during the natural
healing process, reducing the size of the tongue and its
propensity to block the airway during sleep. Powell's
group reported its findings in the May issue of Otolaryngology
- Head and Neck Surgery, documenting an average 17
percent decrease in tongue volume in patients who
underwent a series of treatments.
Severe medical problem
Obstructive sleep apnea
affects some 20 million Americans, and it is associated
with nearly 38,000 cardiac deaths annually. The condition
is characterized by frequent disruption of nighttime
breathing when the base of the tongue or the soft palate
blocks the upper airway. When breathing stops, the person
rouses him or herself just enough to clear the
obstruction by snorting or gasping for air. This cycle
can be repeated more than 100 times each hour.
People who suffer from
severe sleep apnea complain of uncontrollable daytime
fatigue. They are seven times more likely to have an
automobile accident. In addition to compromised
efficiency during their daily routine, affected people
are more likely to have high blood pressure and heart
disease.
According to Powell, sleep
apnea is caused by loss of tissue tone around the airway.
When the floppy tissue partially blocks breathing, the
person is forced to take in the same amount of air
through a smaller opening. As the breathing becomes more
forced, the tissue moves in and out with each breath,
further decreasing tissue tone and causing even more
blockage.
"The opening may
start out the size of a quarter, and then gets to be the
size of a straw," said Powell. "It takes years
for the tissue to completely block the airway, and that's
called sleep apnea."
Traditional treatments for
sleep apnea include medical management, such as dental
devices and masks worn at night to maintain positive air
pressure to keep the airway open. In severe cases,
surgery is used to reduce tissue volume. According to
Powell, the new radiofrequency treatment, called
SomnoplastySM, is a cost-effective, minimally
invasive alternative to surgery, and it may be even more
effective for cases in which both the palate and the
tongue are involved in the blockage.
"The tongue is the
portion that is most difficult to treat because of its
size," said Powell. "If you just fix one and
not the other you still have a blockage in the
tube," he said.
Dramatic improvement
Powell's group studied 18
patients with mild to severe sleep apnea and their
responses to radiofrequency. A small electrode was placed
at the base of the tongue to deliver low dosages of
energy below the mucosal lining, heating the internal
tissue for about five minutes per site. Two sites were
targeted during each session. The treatments were
delivered every three to four weeks to allow for healing
and absorption of the affected tissue between sessions.
Most patients reported minor discomfort for a few days
following each treatment.
Prior to treatment, the
patients suffered an average of 40 incidences of
disrupted breathing per hour every night. After receiving
about six treatments, patients experienced a more than 50
percent reduction in apnea episodes to about 18 per hour.
They also reported less daytime sleepiness and an
increased quality of life. The results were so dramatic
that Powell temporarily discontinued the study to further
analyze the findings.
Magnetic resonance imaging
of the tongue before and after the series of treatments
confirmed that the volume of the tongue had decreased by
an average of 17 percent, with one patient experiencing a
33 percent decrease. Each patient's speech and swallowing
ability was evaluated before and after treatment to
confirm that other normal functions of the tongue were
not impaired by the procedure.
The quick and effective
treatment enabled patients to immediately resume their
normal activities. This contrasts markedly with surgery,
which requires hospitalization and can often result in a
painful recovery, Powell said.
New use envisioned
Powell learned how other
physicians were using radiofrequency energy to decrease
tissue size to treat cancer tumors and shrink enlarged
prostates and thought the same technique could be used to
treat sleep apnea. He started working with Stuart
Edwards, founder of Somnus Medical Technologies, to
develop the clinical application of this technique in the
upper airway.
After testing his idea on
an animal model to correlate the amount of energy applied
with the physical effects of the treatment, he began
using the procedure to reduce the size of the palate and
to clear chronic nasal obstructions in habitual snorers,
or people with mild sleep apnea. He had such success with
the method that he began treating the tongues of patients
with more severe sleep problems and embarked on his
current study.
Powell presented the
results of this and previous radiofrequency studies at
the American Thoracic Society Workshop on Alternative
Therapy May 10 and 11 in Pittsburgh.
"This is the study
that everyone in the sleep community has been waiting
for," he said, adding that if Somnoplasty becomes a
standard treatment for obstructive sleep apnea, it won't
only be physicians who are cheering. Patients and their
families may be able to look forward to their first
peaceful night's sleep in years.
Somnus Medical
Technologies of Sunnyvale, Calif., funded and designed
the proprietary system used in the current study. The
company offers instructional classes to physicians on the
appropriate techniques and uses of the radiofrequency
SomnoplastyTM System. SR
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