WASHINGTON - It's like an angioplasty to clear out clogged sinuses. A new procedure lets doctors snake a balloon up the noses of chronic sinusitis sufferers, stretching their sinus passages to help them breathe easier with less pain than the standard sinus surgery that 350,000 Americans undergo each year.

No one yet knows if balloon sinuplasty works as well as a surgical fix. Only about 100 doctors around the country are trained to offer it, and research is just beginning to track its effectiveness and determine who is a good candidate.

But if sinuplasty proves itself, it promises a long-awaited middle ground between medications and surgery for thousands of patients seeking relief from the misery of repeated sinus infections.

"Clearly sinuplasty will not replace surgery for every patient," cautions Dr. Michael Friedman, an otolaryngologist and chief of head and neck surgery at Chicago's Rush University Medical Center, who heads the first study that will compare the treatments.

"But I think there's a huge number of people who could benefit from this," he adds. "It's really the most exciting thing that's happened in our specialty in probably 15 years."

Sinusitis is an inflammation or infection of the straw-sized passages that drain each of the sinuses that surround the nose and eyes. It can cause swelling and facial pain, debilitating headaches, and a sometimes pus-like nasal congestion.

Acute sinusitis, triggered by colds or bad allergies, usually clears up within a month. But more than 30 million Americans suffer from chronic sinusitis, meaning symptoms last longer than two months or regularly recur. Patients repeatedly try antibiotics, decongestants or steroid-containing nasal sprays, but about a quarter are thought to get inadequate relief.

It's a vicious cycle: Each infection further narrows the already small drainage openings. Then the next cold or allergy attack that causes nasal congestion can be enough to block proper sinus drainage and spur yet another infection.

In severe cases, doctors snake special tools up the nose to enlarge those sinus openings by cutting out inflamed tissue and bone. It's highly effective — only about 20 percent of patients need repeat surgery — but is painful and can cause a week of swelling plus scar tissue that may reblock the sinus.

The new balloon device is snaked to the same spot, but there's no cutting. Instead, inflating the balloon aims to stretch that sinus opening back to its original size or a little bigger, letting air into the sinus to help antibiotics finally flush out infection and end the sinusitis cycle, explains Friedman.

Created by a physician-turned-medical device inventor frustrated by his own sinusitis, it's similar to the way doctors use balloons to push back clogs in heart arteries. Thus, the Food and Drug Administration cleared sale of Acclarent Inc.'s device last summer based mainly on a study of 10 people that found no safety concerns.

How well does it work? There's no research to tell, says Dr. David W. Kennedy of the University of Pennsylvania, who led an examination of sinuplasty for the American Academy of Otolaryngology — and complains that FDA should have required more evidence to back a procedure so different from standard sinus treatment.

Many patients have growths, called polyps, that a balloon can't get rid of. The balloon doesn't fit in every sinus. Like surgery, it often requires general anesthesia to ensure the patient doesn't wiggle. And severe patients often have bone inflammation that must be removed, not just pushed aside, Kennedy stresses.

Doctors are anxiously awaiting results, due in September, of an Acclarent study tracking how more than 100 sinuplasty recipients fared. But to compare sinuplasty to standard treatments, Friedman, who has no financial interest in Acclarent, has begun a study that randomly assigns 80 sinusitis sufferers to surgery, sinuplasty or continued medication.

Even Kennedy acknowledges that sinuplasty, with less pain and scar tissue, may prove useful for milder sinusitis cases or to buy time for people hoping to postpone surgery.

Even if the effects don't last as long as a surgical fix, "I would do this five times compared to having the other procedure done once," says Lynn Sawyer, a Graniteville, S.C., nurse who sought the new procedure after watching surgery patients' painful recoveries.

Her latest sinusitis bout had lasted eight months, causing dizziness, severe eye pressure and repeated migraines. She experienced relief within a day of her December sinuplasty: "It was like being in a dark room and somebody opened up shades, it made that much difference," she recalls.

Three months later, she's thrilled to remain congestion-free despite heavy spring pollen.