In January, 2015, the Food and Drug Administration (FDA) approved a device called the Maestro system, designed to promote weight loss by generating electrical pulses. These small electrical discharges are intended to help reduce hunger pangs by blocking nerve signals from the brain to the stomach.
The implant was approved for use in adults with a BMI (body mass index) of 35 to 45, considered severely obese (a normal BMI is between 18.5 and 25). In addition, the FDA specified that individuals seeking the device must have tried and failed to lose weight in supervised weight loss programs within the past five years. What’s more, the agency stipulated that candidates for the implant must have at least one obesity-related condition such as type 2 diabetes. However, once the device becomes available, physicians can recommend it to any patient.
The implant consists of electrodes placed just above the stomach and under the skin near the ribcage. The procedure takes 60 to 90 minutes. The electrical stimulation suppresses hunger signals carried by the vagus nerve. The vagus is the body’s longest cranial nerve and stretches from the lower abdomen to the brain stem. It carries signals that regulate digestive processes as well as heart rate and respiration. In addition to suppressing hunger pangs, the implant can signal that the stomach is full sooner than you may normally be aware.
In a trial of the device, 157 obese adults lost 8.5 percent more of their excess weight in the course of a year than patients in a control group who received a sham implant. This result was considered somewhat disappointing since the FDA wanted to see weight loss of 10 percent more than those in the control group. Serious side effects included nausea, pain near the implant site, vomiting and surgical complications. Other undesirable symptoms, including pain, heartburn, problems swallowing, belching, mild nausea and chest pain, were also reported.
The cost of the device to patients isn’t known yet but could run as high as $20,000 to $30,000, in the same ballpark as weight-loss surgery. Whether or not health insurers will cover it is another open question.
The upside of the implant is that – unlike weight loss surgery – it is easily reversible. However, given the scope of the obesity epidemic in the U.S., this new device is unlikely to make a big dent. It may interrupt hunger signals or tell you that you’re full so you’ll stop eating, but it won’t affect overeating or eating behaviors that aren’t related to hunger.
Andrew Weil, M.D.
EnteroMedics Maestro Rechargeable System – P130019, U.S. Food and Drug Administration, http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm430696.htm, accessed March 17, 2015