What Happens to the “Old Stomach” in Gastric Bypass?
One of the most frequent questions people ask when I am talking to them about gastric bypass surgery is what happens to the old stomach or the stomach remnant that is bypassed? Sometimes people have the impression that the bypassed stomach remnants or body as it is called may cause some trouble because it is now bypassed. Or sometimes people worry that it loses its blood supply or that it should in fact be removed.
The short answer is that the bypassed stomach remnant continues to do its usual job, namely the production of digestive juices and enzymes, as well as jobs involving the production of hormones or chemical signals to the body and the brain. The one job that it no longer does is the acceptance of ingested food.
Removing the bypassed stomach remnant would increase the magnitude risks and invasiveness of the operation markedly. A stomach removal procedure would require disconnection with all of the blood supply and all of the connective tissues that the bypassed stomach remnant is still attached to. It would also involve disconnecting it from the duodenum, the first part of the intestine where the stomach empties. Then, of course, one would have to remove this large organ through some sort of incision, and altogether these steps would almost certainly require an open surgical procedure instead of the laparoscopy. There would be many disadvantages to removing the stomach: For one thing, it would not be there to use for any future reconstruction if that became necessary, and it would create an increased likelihood of vitamin B12 deficiency and anemia. There would be a heightened risk of surgical complications beyond the gastric bypass procedure.
Might there be any advantages to removing the stomach remnant? Well, there is one mostly theoretical advantage. It has to do with the possibility of stomach ulcer formation in the stomach body or remnant. In some unusual cases, gastric or duodenal ulcers can still form in the bypassed stomach remnant or duodenum, but because of the bypass we no longer have easy access to endoscopically inspect the lining of these structures as we do under normal circumstances. So if a person is having unexplained pain and they have had a gastric bypass, we are not as easily able to perform upper endoscopy (passing a flexible camera tube down into the stomach and duodenum to inspect for ulcers or irritation of the lining). The same would hold true if a tumor were forming in one of these areas. Doctors could investigate with other types of studies, namely imaging studies like CT scan, MRI or ultrasound. Or, if it was felt to be highly important to inspect endoscopically, then the endoscopy could be performed surgically with an incision through the abdominal wall.
So in sum, the bypassed stomach remnant or body remains present because it still has important jobs to do – namely the production of digestive enzymes and juices and hormones which still play an important role in digestion and metabolism. Removing the stomach would increase the invasiveness and risks, magnitude and recovery time of surgery markedly and bring very minimal advantage.