Rochester, MN - A new implantable medical device, developed in collaboration with Mayo Clinic researchers, shows promise as a reversible and less extreme alternative to existing bariatric surgeries, according to findings published in the current issue of the journal Surgery.

In a six-month open label trial involving three medical centers in Australia, Mexico and Norway, the 31 obese participants who received the vagal nerve blocking device, also called VBLOC vagal blocking therapy, lost an average of nearly 15 percent of their excess weight. A quarter of the participants lost more than 25 percent, and three patients lost more than 30 percent.

Michael Camilleri, M.D., is a gastroenterologist who helped design the study and one of the Mayo Clinic researchers whose previous work and know-how contributed to development of the device in collaboration with EnteroMedics, Inc. Dr. Camilleri says the goal is to find a less drastic alternative to bariatric surgery that will still yield significant weight loss. Bariatric surgery techniques include "banding" -- placement of a band around the top part of the stomach to reduce its capacity -- or bypass procedures which reroute food and remove part of the stomach.

Dr. Camilleri says VBLOC therapy is similar to a heart pacemaker, but instead of stimulating a normal, regular heartbeat, it uses high-frequency electricity to block the nerve impulses between the brain and the stomach and pancreas. A pacemaker continuously monitors the heart and regulates its beating. But the patient flips a switch to activate the VBLOC device when the system is worn during the daytime hours so that the blocking signal can influence how the stomach functions and food is digested following a meal.

The lead wires are implanted in the abdomen laparoscopically, with electrodes attached to the vagal nerves and the neuroregulator, a pacemaker-sized device, is implanted just under the skin. While gastric bypass involves removing portions of the digestive tract and rerouting the flow of food and, therefore, is not reversible, the VBLOC delivery system can be removed if desired, and previous studies in animals have indicated that it does not damage or permanently affect the vagal nerves. With VBLOC, there is no distortion of digestive system anatomy as is the case with both gastric bypass and gastric banding, and to date there have been no significant issues related to food intolerance, nausea or vomiting as is common with both bypass and banding.

For additional video and audio resources, connect with Mayo Clinic's News Blog at: http://newsblog.mayoclinic.org/2008/06/23/device-jamming-stomach-nerve-signal-shows-promise-in-obesity/

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