There are several types of restrictive and combined
operations. Each one has its own benefits and risks.
Purely restrictive operations only limit food intake and do not interfere
with the normal digestive process. To perform the operation, doctors create
a small pouch at the top of the stomach where food enters from the
esophagus. At first, the pouch holds about 1 ounce of food and later may
stretch to 2-3 ounces. The lower outlet of the pouch is usually about ½ inch
in diameter or smaller. This small outlet delays the emptying of food from
the pouch into the larger part of the stomach and causes a feeling of
After the operation, patients can no longer eat large amounts of food at one
time. Most patients can eat about ½ to 1 cup of food without discomfort or
nausea, but the food has to be soft, moist, and well chewed. Patients who
undergo restrictive procedures generally are not able to eat as much as
those who have combined operations.
Purely restrictive operations for obesity include adjustable gastric banding
(AGB) and vertical banded gastroplasty (VBG).
Adjustable gastric banding. In
this procedure, a hollow band made of silicone rubber is placed around the
stomach near its upper end, creating a small pouch and a narrow passage into
the rest of the stomach (figure 2). The band is then inflated with a salt
solution through a tube that connects the band to an access port placed
under the skin. It can be tightened or loosened over time to change the size
of the passage by increasing or decreasing the amount of salt solution.
Vertical banded gastroplasty.
VBG uses both a band and staples to create a small stomach pouch, as
illustrated in figure 3. Once the most common restrictive operation, VBG is
not often used today.
operations are easier to perform and are generally safer than
malabsorptive operations. AGB is usually done via laparoscopy, which
uses smaller incisions, creates less tissue damage, and involves shorter
operating time and hospital stays than open procedures. (See below for
more information on laparoscopy.) Restrictive operations can be reversed
if necessary, and result in few nutritional deficiencies.
Disadvantages: Patients who undergo restrictive operations
generally lose less weight than patients who have malabsorptive
operations, and are less likely to maintain weight loss over the long
term. Patients generally lose about half of their excess body weight in
the first year after restrictive procedures. However, in the first 3 to
5 years after VBG patients may regain some of the weight they lost. By
10 years, as few as 20 percent of patients have kept the weight off.
(Although there is less information about long-term results with AGB,
there is some evidence that weight loss results are better than with VBG.)
Some patients regain weight by eating high-calorie soft foods that
easily pass through the opening to the stomach. Others are unable to
change their eating habits and do not lose much weight to begin with.
Successful results depend on the patient’s willingness to adopt a
long-term plan of healthy eating and regular physical activity.
Risks: One of the most common risks of restrictive operations is
vomiting, which occurs when the patient eats too much or the narrow
passage into the larger part of the stomach is blocked. Another is
slippage or wearing away of the band. A common risk of AGB is breaks in
the tubing between the band and the access port. This can cause the salt
solution to leak, requiring another operation to repair. Some patients
experience infections and bleeding, but this is much less common than
other risks. Between 15 and 20 percent of VBG patients may have to
undergo a second operation for a problem related to the procedure.
Although restrictive operations are the safest of the bariatric
procedures, they still carry risk—in less than 1 percent of all cases,
complications can result in death.
Combined Restrictive/Malabsorptive Operations
Combined operations are the most common bariatric procedures. They
restrict both food intake and the amount of calories and nutrients the
- Roux-en-Y gastric bypass (RGB).
This operation, illustrated in figure 4, is the most common
and successful combined procedure in the United States.
First, the surgeon creates a small stomach pouch to restrict
food intake. Next, a Y-shaped section of the small intestine
is attached to the pouch to allow food to bypass the lower
stomach, the duodenum (the first segment of the small
intestine), and the first portion of the jejunum (the second
segment of the small intestine). This reduces the amount of
calories and nutrients the body absorbs. Rarely, a
cholecystectomy (gall bladder removal) is performed to avoid
the gallstones that may result from rapid weight loss. More
commonly, patients take medication after the operation to
- Biliopancreatic diversion (BPD).
In this more complicated combined operation, the lower
portion of the stomach is removed (see figure 5). The small
pouch that remains is connected directly to the final
segment of the small intestine, completely bypassing the
duodenum and the jejunum. Although this procedure leads to
weight loss, it is used less often than other types of
operations because of the high risk for nutritional
deficiencies. A variation of BPD includes a “duodenal
switch” (see figure 6), which leaves a larger portion of the
stomach intact, including the pyloric valve that regulates
the release of stomach contents into the small intestine. It
also keeps a small part of the duodenum in the digestive
pathway. The larger stomach allows patients to eat more
after the surgery than patients who have other types of
Advantages: Most patients lose weight quickly and
continue to lose for 18 to 24 months after the procedure. With the
Roux-en-Y gastric bypass, many patients maintain a weight loss of 60 to
70 percent of their excess weight for 10 years or more. With BPD, most
studies report an average weight loss of 75 to 80 percent of excess
weight. Because combined operations result in greater weight loss than
restrictive operations, they may also be more effective in improving the
health problems associated with severe obesity, such as hypertension
(high blood pressure), sleep apnea, type 2 diabetes, and osteoarthritis.
Disadvantages: Combined procedures are more
difficult to perform than the restrictive procedures. They are also more
likely to result in long-term nutritional deficiencies. This is because
the operation causes food to bypass the duodenum and jejunum, where most
iron and calcium are absorbed. Menstruating women may develop anemia
because not enough vitamin B12 and iron are absorbed. Decreased
absorption of calcium may also bring on osteoporosis and related bone
diseases. Patients must take nutritional supplements that usually
prevent these deficiencies. Patients who have the biliopancreatic
diversion procedure must also take fat-soluble (dissolved by fat)
vitamins A, D, E, and K supplements, and require life-long use of
special foods and medications.
RGB and BPD operations may also cause “dumping syndrome,” an unpleasant
reaction that can occur after a meal high in simple carbohydrates, which
contain sugars that are rapidly absorbed by the body. Stomach contents
move too quickly through the small intestine, causing symptoms such as
nausea, bloating, abdominal pain, weakness, sweating, faintness, and
sometimes diarrhea after eating. Because the duodenal switch operation
keeps the pyloric valve intact, it may reduce the likelihood of dumping
Risks: In addition to risks associated with restrictive
procedures such as infection, combined operations are more likely to
lead to complications. The risk of death associated with these types of
procedures is lower for the gastric bypass (less than 1 percent of
patients) than for the biliopancreatic diversion with duodenal switch
(2.5 to 5 percent). Combined operations carry a greater risk than
restrictive operations for abdominal hernias (up to 28 percent), which
require a follow-up operation to correct. The risk of hernia, however,
is lower (about 3 percent) when laparoscopic techniques are used.
The Normal Digestive Process
Gastric Bypass Surgery and
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Types of Gastric Bypass
Laparoscopic Bariatric Surgery
Bariatric Surgery for Adolescents
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You? What is the cost of Gastric Bypass Surgery?