This procedure was developed by the doctors A. J. Kremen and John H. Linner in 1954. At that time, it was noticed that patients who underwent total gastrectomy (removal of the whole stomach), with reconstruction of the digestive tract following a similar structure, had significant weight loss and improvement of pre-existing diabetes.
The method is called “Roux-en-Y” to distinguish it from a more recent technique called “omega bypass” or “mini bypass”. The latter was growing fast in France a few years ago but has recently been banned there because of potentially severe complications.
The technique is both restrictive and malabsorptive. A small gastric pouch (neogastrium, the size of a tennis ball) is created (using a calibration probe) to reduce the size of the stomach and food contact. The remaining stomach is not removed, as in sleeve gastrectomy, but left in place, in case disassembly of the bypass is considered (which is exceptional). After that, an intestinal “alimentary limb” (loop) is ascended to the gastric pouch and sutured (anastomosed) to it. The food will pass through the new connection (gastro-jejunal anastomosis) and continue through the alimentary limb (about 150cm) before reaching the second suture with the intestine previously connected to the stomach (jejuno-jejunal anastomosis). At this moment only does the food come in contact with the enzymes of the liver and the pancreas brought by the bilio-pancreatic alimentary limb (about 50cm, connected to the stomach), which contributes to a more efficient intestinal absorption of food in the “common limb”. This bypass leads to malabsorption on top of the restrictive effect caused by the small size of the neogastrium. An additional and important hormonal effect (called incretin effect) is added, because the food no longer comes in contact with the duodenum. Some anti-diabetic drugs (GLP-1 analogues) may mimic this effect after gastric bypass, improving blood glucose (sugar) levels.
The excess weight loss is 70% on average and the improvement (or even remission) of obesity-related comorbidities such as type II diabetes is greater than with gastric banding or sleeve gastrectomy.
The procedure lasts about 2 hours, and the vast majority of cases are performed using laparoscopy.
The patient usually stays hospitalized for 4 days.
Similarly to sleeve gastrectomy, one of the main complications of the bypass is leakage (fistula), which occurs in about 3% of cases. It represents a clinical emergency as it may lead to death from peritonitis. Other common complications include hemorrhage, delayed perforation of the suture (allowing food to pass through), anastomotic ulcers (greatly increased by smoking), excessively narrow suture or anastomotic stenosis (closure), nutritional deficiencies, internal hernia (possible even after careful suturing of gaps).
Of course, as in any surgical procedure, general complications may also occur: visceral or vascular injury, gas or pulmonary embolism (more frequent in more obese patients), pulmonary or urinary infection, COVID-19 infection (more severe in obese patients), pneumothorax, cardiac or vascular accidents, hernias (through operative scars), etc.
The operative mortality is about 0.4%.
Sleeve or bypass? How to choose your bariatric intervention?
The patient chooses the intervention after having received the most complete and accurate possible information, and a period of reflection. It is your body. Our role is to guide you towards the best choice, based on your medical and surgical history. For example, in the event of pre-existing gastroesophageal reflux or severe diabetes, a gastric bypass will be preferred. In the event of essential medication intake (which shouldn’t be malabsorbed) or history of abdominal surgery (below the stomach, with risks of adhesions and lesser freedom of the small intestine), a gastric sleeve should be preferred.