Weight loss only a snip away?
2007-07-03 12:40
Washington - An old ulcer operation is getting new attention as a possible alternative obesity surgery: a quick snip of a nerve that helps control hunger.
It is far from clear if cutting the vagus nerve really helps - initial pilot studies in a few dozen patients have just begun.
Sceptics abound, and even proponents say it would not lead to nearly as much weight loss as more traumatic operations that shrink the stomach and reroute intestines.
It is part of a hunt for middle-ground options for people scared of today's surgery, or those not quite fat enough to qualify for it.
"By no means do I think this is a panacea," cautions Dr Robert Lustig of the University of California, San Francisco, who is studying the method along with University of Rochester surgeons.
"But I think this will be a rational alternative for a cadre of patients that are sort of in the middle there. With as much obesity as we have in this country, that's a big middle."
More than 177 000 people underwent obesity surgery last year, according to the American Society for Metabolic and Bariatric Surgery. The most popular method is gastric bypass, stapling the stomach to create a tiny pouch. Options include placing an adjustable band around the stomach, or cutting off the stomach's side and rerouting the intestines.
Searching for alternatives
Surgery can produce life-altering weight loss, if recipients adhere to diet and exercise advice, but each method comes with varying degrees of pain and risk, including a rare chance of death. So doctors are searching for alternatives.
Enter the vagus nerve, which snakes from the brain to the abdomen, with fibres reaching into multiple organs with different effects. Among them: The nerve spurs gastric acid production, and in the 1970s, surgery to cut where it attaches to the front and back of the stomach brought ulcer sufferers great relief - after they recovered from open-abdominal surgery. Once better acid-reducing medications came along, this arduous operation was abandoned.
Yet surgeons at the time noticed, and subsequent animal studies confirmed, that these vagotomies could trigger weight loss. In addition to a less acidic stomach's slower digestion, the vagus helps control appetite-stimulating brain hormones and signals our bodies to store more fat, Lustig explains.
Since doctors today can snip the nerve far less invasively, through just five pencil-sized cuts in the abdomen, it was time to test in the obese.
Thirty patients had a vagus snip at UCSF or the University of Rochester. The study is not complete. But of the 11 who are a year past surgery, all but one are shedding pounds, losing an average of 18% of excess weight so far, Lustig and Rochester's Dr Thad Boss reported at last month's bariatric society meeting.
They suffered no serious side effects, and went home hours later with little pain.
'I have my doubts...'
"Every patient who had the vagus nerve cut says they're not hungry," adds Lustig - although the one who didn't respond got hungry again six weeks after surgery, perhaps because the nerve healed.
That's less than half the weight loss of standard surgeries, warns Dr Neil Hutcher of Bon Secour St Mary's Hospital and a past president of the bariatric society.
"I have my doubts that vagotomy alone is going to be a significant weapon," says Hutcher, who often cuts the nerve during standard gastric bypasses for a different reason - to help those patients avoid the side effect of heartburn-causing acid build-up.
But, when surgeons added a vagotomy to 25 patients getting bands on their stomachs, the nerve-snip seemed to make that usually more modest operation about as effective as a gastric bypass - with 43% loss of excess weight at six months, and counting.
For a more rigorous study, Rochester's Boss is about to recruit 60 more patients headed for band surgery, giving half a vagotomy as well.
- AP