WASHINGTON — Federal regulators have approved an appetite-suppressing implant designed to treat obesity by zapping nerves that connect the stomach and the brain.

The Maestro Rechargeable System uses electrodes implanted in the abdomen to stimulate the vagus nerve, which signals to the brain that the stomach is empty or full. Patients and doctors can adjust the device settings using external controllers.

Shares of EnteroMedics rose in trading Wednesday after the Food and Drug Administration said it approved the device for certain patients who are severely obese. It’s the first medical device approved for obesity since the agency’s 2007 approval of a gastric band from Ethicon.

The FDA approved the device for patients 18 and older who have been unable to lose weight via a supervised weight-loss program and have a body mass index of 35 to 40 with one other obesity-related health condition, such as diabetes. BMI is an estimate of body fat based on weight and height. Someone who is 5-foot-9 would be severely obese — with a BMI of 35 — at 240 pounds.

EnteroMedics said the device’s two electrodes are implanted via a minimally-invasive surgical procedure, which could make the device system a less invasive alternative to other weight-loss surgeries. The device has an external battery that needs to be recharged weekly. The St. Paul, Minnesota-based company compares it to a pacemaker.

A company executive said the device is already approved in Europe and Australia though it is not yet on sale. EnteroMedics plans to focus on the device’s U.S. launch, targeting sales to surgical centers. The company is also pursuing reimbursement from health care insurance providers.

EnteroMedics Inc. stock gained 30 cents, or 25 percent, to $1.47 in morning trading.

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