 |
|
|
 |
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. 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
Normal Digestive Process
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.
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.
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).
| • |
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. |
| • |
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.
| • |
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. |
| • |
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.
|
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
| • |
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. |
| • |
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. |
Risks
| • |
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. |
| • |
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. |
| • |
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. |
| • |
Women of childbearing age should avoid pregnancy
until their weight becomes stable because rapid weight loss and
nutritional deficiencies can harm a developing fetus. |
|
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.
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:
| • |
a BMI of 40 or more |
| • |
a life-threatening obesity-related health problem
such as diabetes, severe sleep apnea, or heart disease and a BMI
of 35 or more |
| • |
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:
| • |
unlikely to lose weight successfully with nonsurgical
measures? |
| • |
well informed about the surgical procedure and the
effects of treatment? |
| • |
determined to lose weight and improve your health? |
| • |
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)? |
| • |
aware of the potential for serious complications,
dietary restrictions, and occasional failures? |
| • |
committed to lifelong medical
follow-up? |
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.
|
Content provided by National Institute
of Diabetes and Digestive and Kidney Diseases.
For advertising info, please contact Terry McGovern terry.mcgovern@latimes.com at (213) 473-2599
Top |
|
|
