The newest and most exciting breakthrough in medical is gastric bypass surgery. Gastric Bypass is also called "Roux en-Y" procedure, named after the French surgeon, Dr. Roux, who first described this reconstruction in the 1800's. The bowel is cut, and reconstructed in a Y configuration, so that two parts of the GI tract can feed into one. This surgery involves creating a small (less than one ounce) vertically oriented stomach pouch, as well as a bypass of most of the stomach and a varying amount of small intestine. As a result, weight loss is accomplished both by restriction of food and by malabsorption of nutrients. The Gastric Bypass provides an excellent tool for gaining long-term control of weight, without the hunger or craving usually associated with small portions, or with dieting. Weight loss of 80 - 100% of excess body weight is achievable for most patients, and long-term maintenance of weight loss is very successful -- but does require adherence to a simple and straightforward behavioural regimen.
To understand what gastric bypass surgery is, it is important to know the normal course of digestion. In normal digestion, food passes through the stomach and enters the small intestine, where most of the nutrients and calories are absorbed. It then passes into the large intestine (colon), and the remaining waste is eventually excreted.
Now in this surgery, the surgeon staples across the top portion of the stomach to create a very small stomach pouch. The surgeon then connects the new stomach pouch to the small intestine, bypassing some of the upper and more absorptive part of the small intestine. The operation is complex and difficult, whether performed by an open incision, or by laparoscopy. It can be organized into three steps:
- Division or partitioning of the stomach into two parts - an upper small pouch, and a lower, large pouch.
- Creation of a Y-connection in the small bowel, to make a new end to connect to the stomach.
- Connection of the new small bowel end to the upper stomach pouch, to bypass the stomach.
The first step is the creation of a small gastric pouch from the patient's original stomach. The pouch size is approximately 30-40 cc or slightly more than two ounces. The pouch is somewhat like an extension of the oesophagus but, when completed, is completely separated from the remainder of the stomach. The pouch is created along the more muscular side of the stomach and thus is less likely to stretch over time. This is the patient's new stomach and because it is significantly smaller than the original stomach far less food can be stored here before becoming full. In this way the feeling of fullness occurs much earlier when the patient eats and far less is eaten for each meal. Most patients who have undergone the gastric bypass indicate that they are far less interested in food and that their appetite is vastly diminished.
The next step in the procedure involves dividing the jejunum i.e. the second segment of the small bowel approximately 50-100 cm beyond its origin and connecting the bottom portion to the gastric pouch. Food now travels from the mouth to the oesophagus, into the gastric pouch and then immediately into the jejunum or Roux limb. Food no longer goes to the larger portion of the stomach. None of the stomach is removed and the secretions from the remainder of the stomach, now called the gastric remnant, continued to travel downstream into the first portion of the small bowel, called the duodenum, and combine with juices from the pancreatic gland and the liver.
The third step in the procedure involves the reconnection of the bowel (the first 50-100 cm of the jejunum and the duodenum containing the juices from the stomach, pancreas, and liver and called the biliopancreatic limb) to the segment of small bowel that was connected to the gastric pouch (the Roux limb). It is the distance between the gastric pouch and the place where the biliopancreatic limb is connected that determines the length of the bypass and the degree of malabsorption created by the operation. This distance is selected based on the patients BMI. The average length of the small bowel before surgery is thought to be approximately 18 ft. with the jejunum accounting for the first 2/5 of the small bowel. The length of the Roux limb that is created ranges from 75 cm to 180 cm (3-6 ft). The average time it takes to complete the Laparoscopic Roux-en-Y Gastric Bypass is approximately 2 hours. If the patient has gallstones, the surgeon may choose to remove the gallbladder as a preventative measure since there is a high incidence of gallstone formation upon weight loss.
This surgery reduces the amount of food eaten as well as decreases absorption of the food and calories consumed. So one will feel full more quickly than when their stomach was its original size, which reduces the amount of food the person will eat and thus the calories consumed. Bypassing part of the intestine also results in fewer calories being absorbed. This leads to weight loss. There is very little interference with normal absorption of food since the operation works by reducing food intake, and reducing the feeling of hunger. The result is a very early sense of fullness, followed by a very profound sense of satisfaction. Even though the portion size may be small, there is no hunger, and no feeling of having been deprived: when truly satisfied, you feel indifferent to even the choicest of foods. Patients continue to enjoy eating - but they enjoy eating a lot less. Ingestion of concentrated sugar is also essentially prohibited because doing so results in "dumping." Dumping is a group of unpleasant symptoms that resembles food poisoning (nausea, vomiting, diarrhea, abdominal cramps, flushing, and palpitations) that occurs when simple sugars enter the small intestine without first being properly digested by the stomach. Many people also report diminished appetite after Roux-en-Y gastric bypass, as well as a change in the taste of food. These are additional ways the gastric bypass causes weight loss. Following RNY surgery, patients are at risk for developing anemia because of poor absorption of iron and vitamin B12. Therefore, dietary supplementation of these nutrients is required. Poor absorption of calcium may also occur. Thus, calcium supplements must also be taken postoperatively.