Weight Loss:
Surgical procedures done
Restriction Operations ("stomach stapling")
Food intake is restricted by creating a small pouch at the top of the
stomach where the food enters from the esophagus. The pouch initially holds
about 1 ounce of food and expands to 2-3 ounces with time. The pouch's
lower outlet usually has a diameter of about 1/4 inch. The small outlet
delays the emptying of food from the pouch and causes a feeling of fullness.
After an operation, the person usually can eat only a half to
a whole cup of food without discomfort or nausea. Also, food has to be
well chewed. For most people, the ability to eat a large amount of food
at one time is lost, but some patients do return to eating modest amounts
of food without feeling hungry.
Restriction operations for obesity include gastric banding and
vertical banded gastroplasty. Both operations serve only to restrict food
intake. They do not interfere with the normal digestive process.
These surgeries are not as popular as they were years ago as the weight
re-gain rate is high. Risks include staple line disruption and GERD.
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Gastric banding. In this procedure, a band made of special
material is placed around the stomach near its upper end, creating a small
pouch and a narrow passage into the larger remainder of the stomach (figure
2). In the future, it may be possible to perform gastric banding with smaller
incisions through a laparoscope, a flexible fiberoptic tube and light source
through which some surgical instruments may be passed. Laparoscopic gastric
banding has not yet been approved by the Food and Drug Administration.
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Vertical banded gastroplasty (VBG). This procedure is the
most frequently used restrictive operation for weight control. As figure
3 illustrates, both a band and staples are used to create a small stomach
pouch.
Restrictive operations lead to weight loss in almost all patients. However,
weight regain does occur in some patients. About 30 percent of persons
undergoing vertical banded gastroplasty achieve normal weight, and about
80 percent achieve some degree of weight loss. However, some patients are
unable to adjust their eating habits and fail to lose the desired weight.
In all weight-loss operations, successful results depend on your motivation
and behaviors.
A common risk of restrictive operations is vomiting caused by
the small stomach being overly stretched by food particles that have not
been chewed well. Other risks of VBG include erosion of the band, breakdown
of the staple line, and, in a small number of cases, leakage of stomach
juices into the abdomen. The latter requires an emergency operation. In
a very small number of cases (less than 1 percent) infection or death from
complications can occur.
Surgeries which cause malabsorption and interfer
with digestion
Gastric Bypass Operations
These operations combine creation of small
stomach pouches to restrict food intake and construction of bypasses of
the duodenum and other segments of the small intestine to cause malabsorption.
These
are the most common surgeries done today. They are often called 'stomach
stapling' by the surgeons because they include a stomach stapling however,
they are much more invasive surgeries and also include an intestinal by-pass.
Be sure you know which surgery you are having!
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Roux-en-Y gastric bypass (RGB). This operation (figure 4)
is the most common gastric bypass procedure. First, a small stomach pouch
is created by stapling or by vertical banding. This causes restriction
in food intake. Next, a Y-shaped section of the small intestine is attached
to the pouch to allow food to bypass the duodenum (the first segment of
the small intestine) as well as the first portion of the jejunum (the second
segment of the small intestine). This causes reduced calorie and nutrient
absorption.
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Extensive gastric bypass (biliopancreatic diversion). In
this more complicated gastric bypass operation (figure 5), portions of
the stomach are removed. The small pouch that remains is connected directly
to the final segment of the small intestine, thus completely bypassing
both the duodenum and jejunum. Although this procedure successfully promotes
weight loss, it is not widely used because of the high risk for nutritional
deficiencies. The Duodenal switch is a form of BPD however, 2 inches
of the 10 inch duodenum is left which may help with nutritional deficiencies.
Gastric bypass operations (figures 4 and 5) that cause malabsorption and
restrict food intake produce more weight loss than restriction operations
(figures 2 and 3) that only decrease food intake. Patients who have bypass
operations generally lose two-thirds of their excess weight within 2 years.
The risks for pouch stretching, band erosion, breakdown of staple
lines, and leakage of stomach contents into the abdomen are about the same
for gastric bypass as for vertical banded gastroplasty. However, because
gastric bypass operations cause food to skip the duodenum, where most iron
and calcium are absorbed, risks for nutritional deficiencies are higher
in these procedures. Anemia may result from malabsorption of vitamin
B12 and iron in menstruating women, and decreased absorption of calcium
may bring on osteoporosis and metabolic bone disease. Patients are
required to take nutritional supplements that usually prevent these deficiencies.
Gastric bypass operations also may cause "dumping syndrome," whereby
stomach contents move too rapidly through the small intestine. Symptoms
include nausea, weakness, sweating, faintness, and, occasionally, diarrhea
after eating, as well as the inability to eat sweets without becoming so
weak and sweaty that the patient must lie down until the symptoms pass.
If food is not thoroughly chewed, it can get caught in the opening into
the intestine (called the stoma). This causes intense pain until the food
dissolves and passes. It also can cause continuous vomiting. If the
food does not dissolve, it will have to be surgically removed. This requires
1-3 days in the hospital.
The more extensive the bypass operation, the greater is the risk
for complications and nutritional deficiencies. Patients with extensive
bypasses of the normal digestive process require not only close monitoring,
but also life-long use of special foods and medications.
Explore Benefits and Risks
Surgery to produce weight loss is a serious undertaking. Each individual
should clearly understand what the proposed operation involves. Patients
and physicians should carefully consider the following benefits and risks:
Benefits
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Immediately following surgery, most patients lose weight rapidly and continue
to do so until 18 to 24 months after the procedure. Although most patients
then start to regain some of their lost weight, few regain it all.
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Surgery improves most obesity-related conditions. For example, in one study
blood sugar levels of most obese patients with diabetes returned to normal
after surgery. Nearly all patients whose blood sugar levels did not return
to normal were older or had had diabetes for a long time.
Risks
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Ten to 20 percent of patients who have weight-loss operations require
followup operations to correct complications. Abdominal hernias are
the most common complications requiring followup surgery. Less common complications
include breakdown of the staple line and stretched stomach outlets.
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More than one-third of obese patients who have gastric surgery develop
gallstones. Gallstones are clumps of cholesterol and other matter that
form in the gallbladder. During rapid or substantial weight loss a person's
risk of developing gallstones is increased. Gallstones can be prevented
with supplemental bile salts taken for the first 6 months after surgery.
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Nearly 30 percent of patients who have weight-loss surgery develop nutritional
deficiencies such as anemia, osteoporosis, and metabolic bone disease.
These deficiencies can be avoided if vitamin and mineral intakes are maintained.
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Women of childbearing age should avoid pregnancy until their weight becomes
stable because rapid weight loss and nutritional deficiencies can harm
a developing fetus.
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