Bariatric (weight-loss) surgery alters the stomach, intestine, or both to produce weight loss.
In the United States, more than 200,000 people have bariatric surgery each year. This number accounts for almost two thirds of the total number of bariatric procedures done worldwide. These procedures result in substantial weight loss. People may lose half or even more of their excess weight and as much as 80 to 160 pounds. Weight loss is rapid at first, and then slows gradually over a period of about 2 years. Weight loss is often maintained for years. The loss greatly reduces the severity and risk of weight-related medical problems (such as high blood pressure and diabetes). It improves mood, self-esteem, body image, activity level, and the ability to work and interact with other people.
When obesity is severe—when body mass index (BMI) is more than 40—surgery is the treatment of choice. Surgery is also appropriate when people with a BMI of more than 35 have serious weight-related health problems, such as diabetes, high blood pressure, sleep apnea, or heart failure.
To qualify for surgery, people also need to do the following:
Usually, age alone is not a factor when bariatric surgery is being considered. In people under 18, bariatric surgery has had good short-term results. However, experience with this surgery in this age group is limited. Many people over 65 have had a bariatric procedure, but results have been mixed, and the risk of complications may be higher. However, in this age group, other factors, such as whether a person has other disorders or can function well, may be more important than age.
Surgery is not appropriate if people have a psychiatric disorder that is not under control (such as major depression), if they abuse drugs or alcohol, or if they have cancer or another life-threatening disorder.
Bariatric surgery is usually done using a flexible viewing tube (laparoscope) inserted into a small incision (about 1 inch long) just below the navel. This technique is called laparoscopy. Four to six other surgical instruments are then inserted into the abdomen through similar small incisions. Whether laparoscopy can be used depends on the type of procedure and the person's size. If laparoscopy cannot be used, surgery involves a larger abdominal incision (called open abdominal surgery, or laparotomy). Compared with open abdominal surgery, laparoscopy is much less invasive and recovery is much more rapid.
Bariatric surgery may involve
Both of these procedures limit the amount of food people can eat.
The most common procedures done in the United States include the Roux-en-Y gastric bypass, sleeve gastrectomy, and adjustable gastric banding.
Roux-en-Y gastric bypass:
This procedure accounts for 80% of the bariatric procedures done in the United States. Roux-en-Y gastric bypass can often be done using a laparoscope.
For this procedure, a small part of the stomach is detached from the rest, creating a small stomach pouch. As a result, the amount of food that can be eaten at one time is drastically reduced The stomach pouch is connected to a lower part of the small intestine (called the jejunum). Thus, a large part of the of small intestine is bypassed. This arrangement resembles a Y—hence the name. The opening between the pouch and the intestine is made narrow. As a result, food moves slowly out of the pouch into the intestine, and people may feel full for a longer time. Because food bypasses the lower part of the stomach and the upper part of the small intestine (duodenum), where much of the absorption occurs, the amount of food and calories absorbed is reduced. However, digestive juices (bile acids and pancreatic enzymes) still mix with food, although in a lower part of the small intestine. Thus, food is digested, and nutrients, including vitamins and minerals, are still absorbed, reducing the risk of nutritional deficiencies.
Gastric bypass (and sleeve gastrectomy) result in certain hormonal changes. These changes may result in feeling full sooner and may contribute to weight loss. These changes also improve how the body uses glucose (a sugar), possibly helping reduce the severity of diabetes or causing it to resolve.
Most people stay in the hospital overnight or longer.
For many people who have had a gastric bypass, eating foods high in fat and refined sugar can cause dumping syndrome. Symptoms include indigestion, nausea, diarrhea, abdominal pain, sweating, light-headedness, and weakness. Dumping syndrome occurs when undigested food from the stomach moves into the small intestine too quickly.
Biliopancreatic diversion with a duodenal switch:
This procedure accounts for fewer than 5% of bariatric procedures done in the United States. This procedure can sometimes be done using a laparoscope.
Part of the stomach is removed. In contrast to the Roux-en-Y gastric bypass, the part of the stomach that is left connects normally to the esophagus and the small intestine. Also, the valve between the stomach and small intestine is left intact and can function normally. Thus, the stomach empties normally. However, the small intestine is divided. The part that connects to the stomach (duodenum) is cut and attached to the lower part (ileum), bypassing much of the middle part of the small intestine (jejunum). As a result, digestive juices (bile acids and pancreatic enzymes) cannot mix with food as well, and absorption is reduced. Nutritional deficiencies often result.
This procedure is being used more often. It causes substantial and sustained weight loss. Part of the stomach is removed, making the stomach into a narrow tube (sleeve). The small intestine is not altered.
Sleeve gastrectomy results in certain hormonal changes, which may result in feeling full sooner and which may contribute to weight loss. These changes also improve how the body uses glucose, possibly helping reduce the severity of diabetes.
Adjustable gastric banding:
This procedure is the second most common bariatric procedure done in the United States. It can be done using a laparoscope.
A band (sometimes called a lap band) is placed at the upper end of the stomach to divide the stomach into a small upper part and a large lower part. Food passes through the band on its way to the intestine, but the band slows the passage of food. Connected to the band is a piece of tubing with a device that allows access to the band at the other end of the tube (through a port). The port is placed just under the skin so that doctors can adjust the tightness of the band after surgery. Fluid can be injected through the port into the band to expand it and make the passageway between the upper and lower stomach smaller. Or fluid can be removed from the band to make the passageway larger. When the passageway is smaller, the upper part of the stomach fills more quickly, sending a message to the brain that the stomach is full. As a result, people eat smaller meals and lose substantial amounts of weight over time.
|Banding the Stomach
For this procedure, an adjustable band is placed around the upper part of the stomach. It enables doctors to adjust the size of the passageway for food through the stomach as needed.
After a small incision is made in the abdomen, a viewing tube (laparoscope) is inserted. While looking through the laparoscope, the surgeon places the band around the upper part of the stomach. On the inside of the band is an inflatable ring, which is connected to tubing with a small port at the other end. The port is placed just under the skin. A special needle can be inserted into the port through the skin. The needle is used to insert a salt water (saline) solution into the band or to remove it. Thus, the passageway can be made smaller or larger. When the passageway is smaller, the upper part of the stomach fills faster, causing people to feel full more quickly and thus eat less.
Before surgery, people are evaluated to determine whether surgery is likely to help them. A physical examination is done, and tests may be done. Tests may include the following:
When certain disorders are detected, measures are taken to control them and thus reduce the risks of surgery. For example, high blood pressure is treated. People who smoke are advised to stop at least 8 weeks before surgery and preferably permanently. Smoking increases the risk of respiratory problems and the risk of ulcers and bleeding in the digestive tract after surgery.
Psychiatric and nutritional evaluations are also done. People should tell their doctor about any drugs or medicinal herbs they are taking. Some drugs, including anticoagulants (such as warfarin) and aspirin, may be stopped before surgery.
After surgery, pain relievers are prescribed.
How quickly people can return to a normal diet varies. For about the first 2 weeks, the diet is mostly liquids. People are asked to drink small amounts frequently throughout the day. They should drink as much fluid as prescribed. Most of the fluid should be a liquid protein supplement. For the next 2 weeks, people should consume a soft diet consisting mostly of mashed or pureed high-protein foods and protein supplements. After 4 weeks, they can start eating solid foods. The following can help people avoid digestive problems and discomfort:
Adjusting to new eating patterns can be difficult. People may benefit from counseling and/or support groups.
Usually, people can resume taking their routine drugs after surgery. But tablets may have to be crushed, and if people have been taking long-acting or sustained-release formulations of drugs, doctors must switch them to immediate-release formulations.
People should start walking or doing leg exercises the day after surgery. To avoid blood clots, they should not stay in bed for long periods of time. They can return to their usual activities after about 1 week and to their usual exercises (such as aerobics and strength training) after a few weeks. They should consult their doctor before doing any heavy lifting and manual labor, which should usually be avoided for 6 weeks.
People may experience pain, and some have nausea and vomiting. Constipation is common. Drinking more fluids and not staying in bed too long at a time can help relieve constipation.
Serious complications, such as problems with the incision, infections, blood clots that travel to the lungs (pulmonary embolism), and lung problems, can occur after any operation (see Surgery: After Surgery). In addition, the following complications can occur after bariatric surgery:
Average weight loss after surgery depends on the procedure.
For adjustable gastric banding done using a laparoscope, weight loss is
How much weight is lost depends on how often people see their doctor after surgery and how often the band is readjusted. People with a lower BMI before surgery tend to lose more weight.
For sleeve gastrectomy, weight loss is
For Roux-en-Y gastric bypass, weight loss is
This weight loss is maintained for up to 10 years.
Visits to the doctor are scheduled every 4 to 12 weeks during the first several months after Roux-en-Y gastric bypass or sleeve gastrectomy—the time when weight loss is most rapid. Then visits are scheduled every 6 to 12 months. After adjustable gastric bypass done using a laparoscope, visits are scheduled about every 2 months for the first year. Weight and blood pressure are measured, and eating habits are discussed. People should report any problems they are having. Blood tests are done at regular intervals. Bone density, usually with dual-energy x-ray absorptiometry (DEXA), is measured after Roux-en-Y gastric bypass or sleeve gastrectomy.
Doctors also check whether people are responding differently to certain drugs after surgery. These drugs include those used to treat high blood pressure (antihypertensives), diabetes (hypoglycemic drugs and insulin), or high cholesterol levels (lipid-lowering drugs).
Some disorders that were present before surgery tend to resolve or become less severe after bariatric surgery. These disorders include some heart problems, diabetes, obstructive sleep apnea, arthritis, and depression. Diabetes resolves in up to 62% of people 6 years after Roux-en-Y gastric bypass. Risk of death decreases by 25%, mainly because risk of death due to heart disorders or cancer is reduced.
Last full review/revision April 2013 by Adrienne Youdim, MD