Gastric bypass

Gastric bypass is one of the more established surgical approached to weight reduction. The strategy behind this approach is two-fold: reduce the size of the stomach to achieve early satiety after a meal, and bypass part of the intestine to reduce the amount of food absorbed into the body. The most common gastric bypass technique used by bariatric surgeons is called Roux-en-Y, a name derived from the inventor's name and the resulting shape of the intestine.

In a Roux-en-Y gastric bypass, the surgeon reduces the stomach by creating a small pouch out of its top portion using surgical staples or a plastic band. Then she connects the reduced stomach to the middle portion of the small intestine (jejunum), thus bypassing the remainder of the stomach and the upper portion of the small intestine (duodenum). Roux-en-Y gastric bypass can be done as open surgery (via a large abdominal incision) or as a laparoscopic operation, which requires about five small incisions. The open surgery requires up to a week in the hospital, whereas laparoscopic option only a 2-3 day hospital stay. However, postoperative recovery usually takes about 3-6 weeks.

Gastric bypass usually produces dramatic weight loss much of which is often maintained long-term. Generally, weight loss start right after he operation and continues for a year or more thereafter. Various studies reported an average loss of a third to a half of excess weight (the weight above optimal range). However, some of the lost weight may be eventually regained because even the "redisigned" GI tract may partly adapt to accommodate larger quanities of food. Thus, bariatric surgery, while providing a dramatic weight loss impetus, does not eliminate the need for healthy lifestyle.

Gastric bypass is a major surgery, whether laparoscopic or open, and should not be considered lightly. There are serious short and long-term risks. The short-term risks are similar to those of other abdominal surgeries and include infection, intestinal perforation, bleeding, embolism, dumping syndrome and so forth. Long-term risks are mainly related to the disruptions in digestion and absorption caused by the GI tract redesign. In particular, about a third of gastric by-pass patient develop gallstones or nutritional deficiencies.

Roux-en-Y gastric bypass has the following main long-term risks and complications:

• Anemia develops in about a third of patients, mainly due to iron and/or vitamin B12 deficiency resulting from malabsorption.
• A variety of other conditions may arise or worsen due to deficiency of various vitamins and minerals caused by malabsorption. For example, malabsorption of calcium, magnesium and vitamin D may lad to osteoporosis (weak, brittle bones).
• Stomal stenosis (narrowing of sutured juncture between stomach and intestines) develops in about 10% of patients, causing nausea and vomiting after eating.
• Ulcers develop in about 10% of patients.
• Other complications include loss of staples, hernia, enlargement of pouch and so forth.

• Since most long-term complications of gastric bypass surgery are nutritional, it is critical to work with a dietician and/or nutrition-focused gastroenterologist to minimize the risk of nutritional deficiencies.

  See also the index of studies related to gastric bypass and in particular to its Roux-en-y variant.

  
  

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