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Gastric Surgery for Severe Obesity
Severe obesity is a chronic condition that is difficult to treat
through diet and exercise alone. Gastrointestinal surgery is the
best option for people who are severely obese and cannot lose weight
by traditional means or who suffer from serious obesity-related
health problems. The surgery promotes weight loss by restricting
food intake and, in some operations, interrupting the digestive
process. As in other treatments for obesity, the best results are
achieved with healthy eating behaviors and regular physical
activity.
People who may consider gastrointestinal surgery include those with
a body mass index (BMI) above 40—about 100 pounds of overweight for
men and 80 pounds for women (see table 1 for a BMI conversion
chart). People with a BMI between 35 and 40 who suffer from type 2
diabetes or life-threatening cardiopulmonary problems such as severe
sleep apnea or obesity-related heart disease may also be candidates
for surgery.
The concept of gastrointestinal surgery to control obesity grew out
of results of operations for cancer or severe ulcers that removed
large portions of the stomach or small intestine. Because patients
undergoing these procedures tended to lose weight after surgery,
some physicians began to use such operations to treat severe
obesity. The first operation that was widely used for severe obesity
was the intestinal bypass. This operation, first used 40 years ago,
produced weight loss by causing malabsorption. The idea was that
patients could eat large amounts of food, which would be poorly
digested or passed along too fast for the body to absorb many
calories. The problem with this surgery was that it caused a loss of
essential nutrients and its side effects were unpredictable and
sometimes fatal. The original form of the intestinal bypass
operation is no longer used.
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Normally, as food moves
along the
digestive tract, digestive juices and
enzymes digest and absorb calories and nutrients (see figure
1). After we chew and swallow our food, it moves down the
esophagus to the stomach, where a strong acid continues the
digestive process. The stomach can hold about 3 pints of food
at one time. When the stomach contents move to the duodenum,
the first segment of the small intestine, bile and pancreatic
juice speed up digestion. Most of the iron and calcium in the
foods we eat is absorbed in the duodenum. The jejunum and
ileum, the remaining two segments of the nearly 20 feet of
small intestine, complete the absorption of almost all
calories and nutrients. The food particles that cannot be
digested in the small intestine are stored in the large
intestine until eliminated.
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How Does Surgery Promote Weight Loss?
Gastrointestinal surgery for obesity, also called bariatric
surgery, alters the digestive process. The operations promote
weight loss by closing off parts of the stomach to make it
smaller. Operations that only reduce stomach size are known as
“restrictive operations” because they restrict the amount of
food the stomach can hold.
Some operations combine stomach restriction with a partial
bypass of the small intestine. These procedures create a direct
connection from the stomach to the lower segment of the small
intestine, literally bypassing portions of the digestive tract
that absorb calories and nutrients. These are known as
malabsorptive operations.
Table 1. Body Mass Index
 Body
Mass Index. Find your weight on the bottom of the graph. Go
straight up from that point until you come to the line that
matches your height. Then look to find your weight group.
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What Are the Surgical Options?
There are several types of restrictive and malabsorptive
operations. Each one carries its own benefits and risks.
Restrictive Operations
Restrictive operations serve only to restrict food intake and do
not interfere with the normal digestive process. To perform the
surgery, doctors create a small pouch at the top of the stomach
where food enters from the esophagus. Initially, the pouch holds
about 1 ounce of food and later expands to 2-3 ounces. The lower
outlet of the pouch usually has a diameter of only about ¾ inch.
This small outlet delays the emptying of food from the pouch and
causes a feeling of fullness.
As a result of this surgery, most people lose the ability to eat
large amounts of food at one time. After an operation, the
person usually can eat only ¾ to 1 cup of food without
discomfort or nausea. Also, food has to be well chewed.
Restrictive operations for obesity include adjustable gastric
banding (AGB) and vertical banded gastroplasty (VBG).
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 Adjustable
gastric banding.
In this procedure, a hollow 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). The band is then inflated with a salt
solution. It can be tightened or loosened over time to change
the size of the passage by increasing or decreasing the amount
of salt solution. |
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 Vertical
banded gastroplasty. VBG has been the most common
restrictive operation for weight control. As figure 3
illustrates, both a band and staples are used to create a
small stomach pouch. |
Although restrictive operations lead to weight loss in almost
all patients, they are less successful than malabsorptive
operations in achieving substantial, long-term weight loss.
About 30 percent of those who undergo VBG achieve normal weight,
and about 80 percent achieve some degree of weight loss. Some
patients regain weight. Others are unable to adjust their eating
habits and fail to lose the desired weight. Successful results
depend on the patient’s willingness to adopt a long-term plan of
healthy eating and regular physical activity.
A common risk of restrictive operations is vomiting, which is
caused when the small stomach is overly stretched by food
particles that have not been chewed well. Band slippage and
saline leakage have been reported after AGB. Risks of VBG
include wearing away of the band and breakdown of the staple
line. In a small number of cases, stomach juices may leak into
the abdomen, requiring an emergency operation. In less than 1
percent of all cases, infection or death from complications may
occur.
Malabsorptive Operations
Malabsorptive operations are the most common gastrointestinal
surgeries for weight loss. They restrict both food intake and
the amount of calories and nutrients the body absorbs.
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 Roux-en-Y
gastric bypass (RGB). This operation, illustrated in
figure 4, is the most common and successful malabsorptive
surgery. First, a small stomach pouch is created 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 bypass reduces the
amount of calories and nutrients the body absorbs. |
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Biliopancreatic diversion (BPD). In this more
complicated malabsorptive operation, portions of the stomach
are 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 successfully promotes weight loss, it
is less frequently used than other types of surgery 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. |
 Malabsorptive
operations produce more weight loss than restrictive operations,
and are more effective in reversing the health problems
associated with severe obesity. Patients who have malabsorptive
operations generally lose two-thirds of their excess weight
within 2 years.
In addition to the risks of restrictive surgeries, malabsorptive
operations also carry greater risk for nutritional deficiencies.
This is because the procedure 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 metabolic bone disease. Patients
are required to take nutritional supplements that usually
prevent these deficiencies. Patients who have the
biliopancreatic diversion surgery must also take fat-soluble
(dissolved by fat) vitamins A, D, E, and K supplements.
RGB and BPD operations may also cause “dumping syndrome.” This
means that stomach contents move too rapidly through the small
intestine. Symptoms include nausea, 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 syndrome.
The more extensive the bypass, the greater the risk for
complications and nutritional deficiencies. Patients with
extensive bypasses of the normal digestive process require close
monitoring and life-long use of special foods, supplements, and
medications.
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Explore Benefits and Risks
Surgery to produce weight loss is a serious undertaking. Anyone
thinking about surgery should understand what the operation
involves. Patients and physicians should carefully consider the
following benefits and risks:
Benefits
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Right after surgery, most patients lose weight quickly and
continue to lose for 18 to 24 months after the procedure.
Although most patients regain 5 to 10 percent of the weight
they lost, many maintain a long-term weight loss of about 100
pounds. |
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Surgery improves most obesity-related conditions. For example,
in one study blood sugar levels of 83 percent of 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 lived with diabetes for a long time.
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Risks
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Ten to 20 percent of patients who have weight-loss surgery
require follow-up operations to correct complications.
Abdominal hernia was the most common complication requiring
follow-up surgery, but laparoscopic techniques seem to have
solved this problem. In laparoscopy, the surgeon makes one
or more small incisions through which slender surgical
instruments are passed. This technique eliminates the need
for a large incision and creates less tissue damage.
Patients who are superobese (>350 pounds) or have had
previous abdominal surgery may not be good candidates for
laparoscopy, however. Less common complications include
breakdown of the staple line and stretched stomach outlets.
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Some obese patients who have weight-loss 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 increases. Taking supplemental bile salts for the
first 6 months after surgery can prevent gallstones.
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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
usually can be avoided if vitamin and mineral intakes are
high enough.
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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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Medical Costs
Gastrointestinal surgery costs about $15,000. Medical insurance
coverage varies by state and insurance provider. If you are
considering gastrointestinal surgery, contact your regional
Medicare or Medicaid office or insurance plan to find out if the
procedure is covered.
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Is the Surgery for You?
Gastrointestinal surgery may be the next step for people who
remain severely obese after trying nonsurgical approaches, or
for people who have an obesity-related disease. Candidates for
surgery have:
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a BMI of 40 or more |
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a life-threatening obesity-related health problem such as
diabetes, severe sleep apnea, or heart disease and a BMI of 35
or more |
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obesity-related physical problems that interfere with
employment, walking, or family function. |
If you fit the profile for surgery, answers to the following
questions may help you decide whether weight-loss surgery is
appropriate for you.
Are you:
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unlikely to lose weight successfully with nonsurgical
measures?
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well informed about the surgical procedure and the effects
of treatment?
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determined to lose weight and improve your health?
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aware of how your life may change after the operation
(adjustment to the side effects of the surgery, including
the need to chew well and inability to eat large meals)?
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aware of the potential for serious complications, dietary
restrictions, and occasional failures?
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committed to lifelong medical follow-up?
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Remember: There are no guarantees for any method,
including surgery, to produce and maintain weight loss. Success
is possible only with maximum cooperation and commitment to
behavioral change and medical follow-up—and this cooperation and
commitment must be carried out for the rest of your life.
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Additional
Reading
Gastrointestinal Surgery for Severe Obesity. Consensus
Statement, NIH Consensus Development Conference, March 25-27,
1991; Public Health Service, National Institutes of Health,
Office of Medical Applications of Research. This publication,
written for health professionals, summarizes the findings of a
conference discussing treatments for severe obesity. Available
from WIN.
Weight Loss for Life. NIH Publication No. 00-3700. This
booklet describes how we lose weight, healthy eating habits, the
importance of physical activity, and behavior change. Available
from WIN.
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Additional
Resource
American Society for Bariatric Surgery
140 NW 75th Drive, Suite C
Gainesville, FL 32607
Phone: (352) 331-4900
Fax: (352) 331-4975
Website:
www.asbs.org
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Weight-control Information Network
1 WIN WAY
BETHESDA, MD 20892-3665
Phone: (202) 828-1025
FAX: (202) 828-1028
Email: WIN@info.niddk.nih.gov
Internet: www.niddk.nih.gov/health/nutrit/nutrit.htm
Toll-free number: 1-877-946-4627
E-mail:
win@info.niddk.nih.gov
The Weight-control Information Network is a service of the
National Institute of Diabetes and Digestive and Kidney Diseases
of the National Institutes of Health, which is the Federal
Government’s lead agency responsible for biomedical research on
nutrition and obesity. Authorized by Congress (Public Law
103-43), WIN provides the general public, health professionals,
the media, and Congress with up-to-date, science-based health
information on weight control, obesity, physical activity, and
related nutritional issues.
WIN answers inquiries, develops and distributes publications,
and works closely with professional and patient organizations
and Government agencies to coordinate resources about weight
control and related issues.
Publications produced by WIN are carefully reviewed by both
NIDDK scientists and outside experts. This fact sheet was also
reviewed by Patricia Choban, M.D., Adjunct Professor of Human
Nutrition and Food Management, Ohio State University and Walter
Pories, M.D., Professor of Surgery and Biochemistry, Brody
School of Medicine at East Carolina University.
This e-text is not copyrighted. The clearinghouse encourages
users of this e-pub to duplicate and distribute as many copies
as desired.
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U.S. DEPARTMENT OF HEALTH AND
HUMAN SERVICES
National Institutes of HealthNIH Publication No. 01-4006
December 2001 |
Source:
http://www.niddk.nih.gov/health/nutrit/pubs/gastric/gastricsurgery.htm
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