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Stanford Report, May 20, 1998

Snoring subdued with new treatment: 5/20/98

Snoring subdued with outpatient radio-frequency treatments

BY RUTHANN RICHTER

Serious snorers ­ whose nighttime habits were raucous enough to drive their partners out of the bedroom ­ slept much more quietly after a series of treatments using radio-frequency energy to shrink the soft palate, Dr. Nelson Powell, co-director of the Stanford Sleep Disorders Research Center, reported this month.

The outpatient procedure, which proved relatively painless with no side effects, shrank tissues in the mouth that can obstruct breathing during sleep. The 22 men and women in the study experienced a mean improvement of 77 percent on a standardized snoring scale and generally slept better after completing the treatments, Powell and his colleagues note in the May issue of the journal Chest.

"The importance of this study is that we showed we were able to give the [radio-frequency] energy safely, with minimal pain, and patients felt better. They didn't snore, which helped them socially," said Powell, a head-and-neck surgeon and clinical associate professor of psychiatry and behavioral sciences. "People with moderate sleep apnea might benefit as well."

Finding an ideal treatment for sleep apnea is his ultimate goal, he said. Sleep apnea affects an estimated 24 percent of men and 9 percent of women between the ages of 30 and 60 in the United States. In this condition, obstructed breathing during sleep cuts off the oxygen supply and arouses the person repeatedly at night. Apnea can result from excess soft tissue in the upper airway, including the tongue, palate and nose. It causes daytime fatigue and puts victims at risk of serious vascular complications, including heart attack and stroke.

Powell now is testing the radio-frequency procedure in another group of patients to help shrink the base of the tongue, the area often responsible for airway blockages associated with apnea. If the technique is successful in such patients, he said, it could replace other treatments for apnea. These include use of a cumbersome sleeping mask to keep the airways open, as well as invasive surgical procedures that are painful and require a hospital stay.

"Over the years, we have been looking for some mechanism that would have efficacy ­ that would make a difference in apnea ­ and could be done with very little pain as an outpatient procedure," he said.

The tissue-shrinking procedure he and his colleagues are testing uses a crescent-shaped wand containing a sheathed electrode that emits a low level of radio-frequency energy. The energy causes molecular particles within tissue cells to vibrate, generating frictional heat of up to 170 degrees Fahrenheit. This temperature is relatively low compared with the heat produced during some standard procedures for apnea, which may use lasers or electrocautery to burn away tissue, Powell said. With radio-frequency, the low-level heat effectively destroys the unwanted cells, he said.

This technique, known as radio-frequency ablation, already has been applied successfully in a variety of medical conditions, including heart rhythm problems, cranial nerve problems, enlarged prostates and some forms of cancer. Physicians using it can target tissues with precision because the effects of the radio-frequency energy quickly drop off as it travels from the electrode, so only targeted cells are affected.

In the newly published study, Powell applied the technique in 18 men and 4 women who snored enough to cause family or social disruption and who experienced chronic daytime fatigue that interfered with their social or professional activities. All of the participants had major airway obstructions involving the soft tissues of the palate. The procedure was done entirely on an outpatient basis, with patients coming to Stanford for an average of 3 1/2 visits over several months to receive treatments lasting just 15 or 20 minutes each. At the end of the treatment period, their soft palates had shrunk by an average of 5.5 millimeters, or about one-fifth of an inch.

All of the patients showed major improvements in their snoring scores, based on a scale of 1 to 10. Before treatments began, the group's average score was 8.3 ­ bothersome enough that another person can't sleep in the same room. After the treatments, the average score was 1.9 ­ a soft, occasional snore. The patients also showed dramatic improvement in a standard measure of daytime sleepiness, known as the Epworth sleepiness scale, with the group's average score falling from 8.5 to 5.2.

"The most important findings were the behavioral components ­ how they slept and how they felt the next day," Powell said.

During treatments, patients received a local anesthetic, and most said they experienced little or no pain. A few took acetaminophen in the few days afterward to control pain. The patients initially had some swelling at the site, but this disappeared after a few days. There were no infections and no problems with speech or swallowing, Powell said.

His co-authors on the study were Dr. Robert Riley, a head-and-neck surgeon and clinical associate professor of psychiatry; Dr. Robert J. Troell, a head-and-neck surgeon and medical sleep specialist; Dr. Kasey Li, a head-and-neck surgeon and medical sleep specialist; Dr. Christian Guilleminault, a professor of psychiatry and medical sleep specialist; and Dr. Marc B. Blumen, a head-and-neck surgeon with the University of Paris.

The study was funded in part by Somnus Medical Technologies, Inc. SR