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Bariatric surgery is used to treat severely obese people. There are four types of operations that are commonly offered in the United States: adjustable gastric band (AGB), Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion with a duodenal switch (BPD-DS), and vertical sleeve gastrectomy (VSG). Each has its own benefits and risks. To select the option that is best for you, you and your physician will consider that operation’s benefits and risks along with many other factors, including BMI, eating behaviors, obesity-related health conditions, and previous operations.
Adjustable Gastric Band
AGB works primarily by decreasing food intake. Food intake is limited by placing a small bracelet-like band around the top of the stomach to produce a small pouch about the size of a thumb. The outlet size is controlled by a circular balloon inside the band that can be inflated or deflated with saline solution to meet the needs of the patient.
Roux-en-Y Gastric Bypass
RYGB works by restricting food intake and by decreasing the absorption of food. Food intake is limited by a small pouch that is similar in size to the adjustable gastric band. In addition, absorption of food in the digestive tract is reduced by excluding most of the stomach, duodenum, and upper intestine from contact with food by routing food directly from the pouch into the small intestine.
Biliopancreatic Diversion With a Duodenal Switch
BPD-DS, usually referred to as a “duodenal switch,” is a complex bariatric operation that principally includes 1) removing a large portion of the stomach to promote smaller meal sizes, 2) re-routing of food away from much of the small intestine to partially prevent absorption of food, and 3) re-routing of bile and other digestive juices which impair digestion.
In removing a large portion of the stomach, a more tubular “gastric sleeve” (also known as a vertical sleeve gastrectomy, or VSG) is created.
The smaller stomach sleeve remains connected to a very short segment of the duodenum, which is then directly connected to a lower part of the small intestine. This operation leaves a small portion of the duodenum available for food and the absorption of some vitamins and minerals.
However, food that is eaten by the patient bypasses the majority of the duodenum. The distance between the stomach and colon is made much shorter after this operation, thus promoting malabsorption. BPD-DS produces significant weight loss. However, there is greater risk of long-term complications because of decreased absorption of food, vitamins, and minerals.
Vertical Sleeve Gastrectomy
VSG historically had been performed only as the first stage of BPD-DS (see above) in patients who may be at high risk for complications from more extensive types of surgery. These patients’ high risk levels are due to body weight or medical conditions. However, more recent information indicates that some patients who undergo a VSG can actually lose significant weight with VSG alone and avoid a second procedure. It is not yet known how many patients who undergo VSG alone will need a second stage procedure. A VSG operation restricts food intake and does not lead to decreased absorption of food. However, most of the stomach is removed, which may decrease production of a hormone called ghrelin. A decreased amount of ghrelin may reduce hunger more than other purely restrictive operations, such as gastric band.
Early complications of these operations can include bleeding, infection, leaks from the site where the intestines are sewn together, and blood clots in the legs that can progress to the lungs and heart.
Examples of complications that may occur later include malnutrition, especially in patients who do not take their prescribed vitamins and minerals. In some cases, if the malnutrition is not addressed promptly, diseases such as pellagra, beri beri, and kwashiorkor may occur along with permanent damage to the nervous system. Other late complications include strictures (narrowing of the sites where the intestine is joined) and hernias.
Two kinds of hernias may occur after a patient has bariatric surgery. An incisional hernia is a weakness that sticks out from the abdominal wall’s fascia (connective tissue) and may cause a blockage in the bowel. An internal hernia occurs when the small bowel is displaced into pockets in the lining of the abdomen. These pockets are created when the intestines are sewn together. Internal hernias are considered more dangerous than incisional ones and need prompt attention to avoid serious complications.
Research indicates that about 10 percent of patients who undergo bariatric surgery may have unsatisfactory weight loss or regain much of the weight that they lost. Some behaviors such as frequent snacking on high-calorie foods or lack of exercise can contribute to inadequate weight loss. Technical problems that may occur with the operation, like a stretched pouch or separated stitches, may also contribute to inadequate weight loss.
Some patients may also require emotional support to help them through the postoperative changes in body image and personal relationships.
Open and Laparoscopic Bariatric Surgery
Bariatric surgery may be performed through “open” approaches, which make abdominal incisions in the traditional manner, or by laparoscopy. With the laparoscopic approach, sophisticated instruments are inserted through 1/2-inch incisions and guided by a small camera that sends images to a television monitor. Most bariatric surgery today is performed laparoscopically because it requires a smaller cut, creates less tissue damage, leads to earlier discharges from the hospital, and has fewer complications, especially postoperative hernias.
However, not all patients are suitable for laparoscopy. Patients who are extremely obese, who have had previous abdominal surgery, or have complicating medical problems may require the open approach.