Gastric
Bypass (Malabsorptive) Surgery
(Malabsorptive
Procedure, Roux-en-Y Gastric Bypass, Biliopancreatic
Diversion)
Gastric
bypass surgery, a type of bariatric surgery (weight
loss surgery), is a surgical procedure that alters
the process of digestion. Bariatric surgery is
the only option today that effectively treats
morbid obesity in people for whom more conservative
measures such as diet, exercise, and medication
have failed.
There
are several types of gastric bypass procedures,
but all of them involve bypassing part of the
small bowel by greater or lesser degrees. For
this reason, procedures of this type are referred
to as malabsorptive procedures, because they involve
bypassing a portion of the small intestine that
absorbs nutrients.
Some
of these procedures also involve stapling the
stomach to create a small pouch that serves as
the "new" stomach or surgically removing part
of the stomach.
Although
a gastric bypass procedure is malabsorptive, it
may also be restrictive because the size of the
stomach is reduced so that the amount of food
that can be eaten is "restricted" due to the smaller
stomach. While malabsorptive procedures are more
effective in causing excess weight to be lost
than procedures that are solely restrictive, they
also carry more risk for nutritional deficiencies.
- roux-en-Y gastric
bypass (RGB)
Roux-en-Y gastric bypass, the most commonly
performed bariatric procedure, is both malabsorptive
and restrictive. This surgery can result in
two-thirds of extra weight loss within two years.
The procedure involves stapling the stomach
to create a small pouch that holds less food
and then shaping a portion of the small intestine
into a "Y". The "Y" portion of intestine is
then connected to the stomach pouch so that
when food is being digested it travels directly
into the lower part of the small intestine,
bypassing the first part of the small intestine
(called the duodenum) and the first part of
the second section of the small intestine (called
the jejunum). The effect of bypassing these
sections of the intestine is to restrict the
amount of calories and nutrients that are absorbed
into the body.
The Roux-en-Y gastric bypass may be performed
with a laparoscope rather than through an open
incision in some patients. This procedure uses
several small incisions and three or more laparoscopes
- small thin tubes with video cameras attached
- to visualize the inside of the abdomen during
the operation. The surgeon performs the surgery
while looking at a TV monitor. Persons with
a Body Mass Index (BMI) of 60 or more or those
who have already had some type of abdominal
surgery are usually not considered for this
technique. A laparoscopic method allows the
physician to make a series of much smaller incisions.
Laparoscopic gastric bypass usually reduces
the length of hospital stay, the amount of scarring,
and results in quicker recovery than an open
procedure.
- biliopancreatic diversion
(BPD)
A biliopancreatic diversion is both restrictive
and malabsorptive, and is a more complicated
procedure than the Roux-en-Y procedure. In this
procedure a large part of the lower stomach
is removed. The small part of stomach that is
left is connected directly to the last part
of the small intestine. As food is digested,
it completely bypasses the duodenum and the
jejunum. Because this procedure may result in
nutritional deficiencies, it is not as commonly
performed.
A variation of the biliopancreatic diversion
is a procedure called the duodenal switch. More
of the stomach is retained, including the valve
that controls the release of food into the small
intestine. A small part of the duodenum is also
retained.
Digestion
is the process by which food and liquid are broken
down into smaller parts so that the body can use
them to build and nourish cells. Digestion begins
in the mouth, where food and liquids are taken
in, and is completed in the small intestine. The
digestive tract is a series of hollow organs joined
in a long, twisting tube from the mouth to the
anus.
The
stomach is where the three mechanical tasks of
storing, mixing, and emptying occur.
Normally,
this is what happens:
- First, the stomach
stores the swallowed food and liquid, which
requires the muscle of the upper part of the
stomach to relax and accept large volumes of
swallowed material.
- Second, the lower part
of the stomach mixes up the food, liquid, and
digestive juices produced by the stomach by
muscle action.
- Third, the stomach
empties the contents into the small intestine.
The
food is then digested in the small intestine and
dissolved by the juices from the pancreas, liver,
and intestine, and the contents of the intestine
are mixed and pushed forward to allow further
digestion.
Malabsorptive
procedures alter this process in different ways
depending on the type of procedure.
Bariatric
surgery is performed because it is currently the
best treatment option for producing lasting weight
loss in obese patients for whom nonsurgical methods
of weight loss have failed.
Potential
candidates for bariatric surgery include:
- persons with a Body
Mass Index (BMI) greater than 40
- men who are 100 pounds
over their ideal body weight or women who are
80 pounds over their ideal body weight
- persons with a BMI
between 35 and 40 who have another condition
such as obesity-related type 2 diabetes, sleep
apnea, or heart disease
Because
the surgery can have serious side effects, the
long-term health benefits must be considered and
found greater than the risk. Despite the fact
that some surgical techniques can be done laparoscopically
with reduced risk, all bariatric surgery is considered
to be major surgery.
Although
not all risks with each procedure are fully known,
bariatric surgery does help many people to reduce
or eliminate some health-related obesity problems.
It may help to:
- lower blood sugar
- lower blood pressure
- reduce or eliminate
sleep apnea
- decrease the workload
of the heart
- lower cholesterol levels
Surgery
for weight loss is not a universal remedy, but
these procedures can be highly effective in people
who are motivated after surgery to follow their
physician's guidelines for nutrition and exercise
and to take nutritional supplements.
There
may be other reasons for your physician to recommend
a gastric bypass procedure.
As with
any surgical procedure, complications may occur.
Some possible complications include, but are not
limited to, the following:
- infection
- blood clots
- pneumonia
- bleeding ulcer
- development of gallstones
With
Roux-en-Y gastric bypass procedures, malabsorptive
symptoms may be more serious with an increased
risk of anemia and loss of fat-soluble vitamins
(vitamins A, D, E, and K). Adequate amounts of
iron, calcium, and vitamin B12 may not be absorbed.
This can cause metabolic bone disease and osteoporosis.
Stomal
stenosis occurs when there is a stricture (tightening)
of the opening between the stomach and intestine
after a Roux-en-Y procedure. When this occurs,
vomiting after eating and sometimes after drinking
may occur. Stomal stenosis can be treated easily
but should be treated immediately.
"Dumping
syndrome" is also more likely to occur with these
procedures because the food in the stomach moves
to the intestines quickly. Symptoms include nausea,
sweating, fainting, weakness, and diarrhea.
There
is a risk that additional surgery may be necessary
because of complications, including gallstones.
One
of the most serious complications of gastric bypass
is a stomach leak that can cause peritonitis to
develop. Peritonitis is an inflammation of the
peritoneum, the smooth membrane that lines the
cavity of the abdomen.
There
may be other risks depending upon your specific
medical condition. Be sure to discuss any concerns
with your physician prior to the procedure.
- Your physician will
explain the procedure to you and offer you the
opportunity to ask any questions that you might
have about the procedure.
- You will be asked to
sign a consent form that gives your physician
permission to perform the procedure. Read the
form carefully and ask questions if something
is not clear.
- In addition to a complete
medical history, your physician may perform
a complete physical examination to ensure you
are in good health before undergoing the procedure.
You may undergo blood tests or other diagnostic
tests.
- You will be asked to
fast for eight hours before the procedure, generally
after midnight.
- If you are pregnant
or suspect that you are pregnant, you should
notify your physician.
- Notify your physician
if you are sensitive to or are allergic to any
medications, latex, iodine, tape, or anesthetic
agents (local and general).
- Notify your physician
of all medications (prescription and over-the-counter)
and herbal supplements that you are taking.
- Notify your physician
if you have a history of bleeding disorders
or if you are taking any anticoagulant (blood-thinning)
medications, aspirin, or other medications that
affect blood clotting. It may be necessary for
you to stop these medications prior to the procedure.
- You may be asked to
begin exercising and alter your diet several
weeks before surgery.
- If you are a woman
of child-bearing age, you may receive birth
control counseling so that you do not become
pregnant in your first year after surgery due
to the risk to the fetus from rapid weight loss.
- You may receive a sedative
prior to the procedure to help you relax.
- The area around the
surgical site may be shaved.
- Based upon your medical
condition, your physician may request other
specific preparation.
Gastric
bypass surgery requires a stay in the hospital.
Procedures may vary depending on which type of
procedure is performed and your physician's practices.
Gastric
bypass surgery will be performed while you are
asleep under general anesthesia. Your physician
will discuss this with you in advance.
Generally,
gastric bypass surgery follows this process:
- You will be asked to
remove clothing and will be given a gown to
wear.
- An intravenous (IV)
line will be started in your arm or hand.
- You will be positioned
lying on your back on the operating table.
- A urinary catheter
may be inserted into your bladder.
- The anesthesiologist
will continuously monitor your heart rate, blood
pressure, breathing, and blood oxygen level
during the surgery.
- The skin over the surgical
site will be cleansed with an antiseptic solution.
- For an open procedure,
the physician will make a single large incision
in the abdominal area. For a laparoscopic procedure,
a series of small incisions in the abdomen will
be made. Carbon dioxide gas will be introduced
into the abdomen to inflate the abdominal cavity
so that the appendix and other structures can
easily be visualized with the laparoscope.
- For an open procedure,
the abdominal muscles will be separated and
the abdominal cavity will be opened. For a laparoscopic
procedure, the physician will insert the laparoscope
and other small instruments.
- For a Roux-en-Y gastric
bypass, the physician will staple the stomach
across the top to create a new small pouch for
a stomach. The rest of the stomach will be separated
from the new pouch and closed off by the staples;
however, the remaining stomach will continue
to produce digestive juices that will be used
in digestion. A portion of the small intestine
will be shaped like a "Y" and connected to the
pouch.
- For a biliopancreatic
diversion, a large part of the lower stomach
will be removed. The small part of stomach that
is left is then connected directly to the last
part of the small intestine. For a duodenal
switch procedure, the physician will retain
more of the stomach, including the valve that
controls the release of food into the small
intestine. A small part of the duodenum will
also be kept.
- A drain may be placed
in the incision site to remove fluid.
- The incision will be
closed with stitches or surgical staples.
- A sterile bandage/dressing
will be applied.
After
the procedure, you will be taken to the recovery
room for observation. Once your blood pressure,
pulse, and breathing are stable and you are alert,
you will be taken to your hospital room. Malabsorptive
stomach surgery usually requires an in-hospital
stay of several days.
You
may receive pain medication as needed, either
by a nurse or by administering it yourself through
a device connected to your intravenous line.
You
will be encouraged to move around as tolerated
while you are in bed, and then to get out of bed
and walk around as your strength improves.
At first
you will receive fluids through an IV. After a
day or two you will be given liquids, such as
broth or clear juice, to drink. As you are able
to tolerate liquids, you will be given thicker
liquids, such as pudding, milk, or cream soup,
followed by foods that you do not have to chew,
such as hot cereal or pureed foods. Your physician
will instruct you about how long to eat pureed
foods after surgery. By one month after your procedure,
you may be eating solid foods.
You
will be instructed about taking nutritional supplements
to replace the nutrients lost due to the reconstruction
of the digestive tract.
Before
you are discharged from the hospital, arrangements
will be made for a follow-up visit with your physician.
Once
you are home, it will be important to keep the
surgical area clean and dry. Your physician will
give you specific bathing instructions. The stitches
or surgical staples will be removed during a follow-up
visit.
The
incision and abdominal muscles may ache, especially
with deep breathing, coughing, and exertion. Take
a pain reliever for soreness as recommended by
your physician. Aspirin or certain other pain
medications may increase the chance of bleeding.
Be sure to take only recommended medications.
You
should continue the breathing exercises used in
the hospital.
You
should gradually increase your physical activity
as tolerated. It may take several weeks to return
to your previous levels of stamina.
You
may be instructed to avoid lifting heavy items
for several months in order to prevent strain
on your abdominal muscles and surgical incision.
Weight
loss surgery can be emotionally difficult because
you will be adjusting to new dietary habits and
a body in the process of change. You may feel
especially tired during the first month following
surgery. Exercise and attending a support group
may be helpful at this time.
Notify
your physician to report any of the following:
- fever and/or chills
- redness, swelling,
or bleeding or other drainage from the incision
site
- increased pain around
the incision site
Following
gastric bypass surgery, your physician may give
you additional or alternate instructions, depending
on your particular situation.
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