A tiny magnetic bracelet implanted at the base of the throat is greatly improving life for some people with chronic heartburn who need more help than medicine can give them.It's a novel way to treat severe acid reflux, which plagues millions of Americans and can raise their risk for more serious health problems.It happens when a weak muscle doesn't close as it should after someone swallows. That lets stomach juices splash back into the throat. Drugs like Nexium and Prilosec reduce acid. But they don't fix the underlying problem, called GERD, or gastroesophageal reflux disease.Rodd Foster had it so bad that he used to sleep sitting up to keep his dinner down. The treatment was "life-changing," said Foster, 61, a plumbing contractor from Canyon Country, Calif. "It's been 30 years since I've been able to eat normally, and now I can eat anything anytime."The device was approved a year ago by the Food and Drug Administration. The Linx device, made by Torax Medical of St. Paul, Minn., is a ring of titanium beads with magnets inside. Doctors place it around the weak muscle at the base of the esophagus in a half-hour operation using a scope and "keyhole" incisions in the belly.The ring reinforces the weak muscle to keep it closed yet is flexible and expands to let food pass when someone swallows. The ring comes in multiple sizes. It is about a half-inch in diameter and expands to about 1.5 inches. People don't feel it once it is implanted.The device costs $5,000, and the operation can run $12,000 to $20,000, depending on hospital charges, said Dr. John Lipham, a surgeon who offers it at the University of Southern California and at Hoag Memorial Hospital Presbyterian in Newport Beach. Many insurers cover it for patients who are not helped enough by antacid medicines."It is a clever device," said another doctor who has used it -- Dr. Donald Castell, a gastroenterologist at the Medical University of South Carolina in Charleston.Up to 20 million Americans have GERD. Chronic acid reflux can raise the risk of a condition called Barrett's esophagus, which can raise the risk of throat cancer.