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The American Society for Bariatric Surgery
describes two basic approaches that weight
loss surgery takes to achieve change:
- Restrictive procedures that decrease
food intake.
- Malabsorptive procedures
that alter digestion,
thus causing the food to be poorly
digested and incompletely absorbed so
that it
is
eliminated in the stool.
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Vertical Banded Gastroplasty
(VBG) is a purely restrictive
procedure. In this procedure
the upper stomach near the
esophagus is stapled vertically
for about
2-1/2 inches (6 cm) to create a smaller stomach pouch. The outlet from the pouch
is restricted by a band or ring that slows the emptying of the food and thus
creates the feeling of fullness
Advantages
- The primary advantage
of this restrictive
procedure is that a
reduced amount of well-chewed
food enters and passes
through the digestive
tract in the usual
order. That allows
the nutrients and vitamins
(as well as the calories)
to be fully absorbed
into the body.
- After 10 years, studies
show that patients
can maintain 50% of
targeted excess weight
loss.
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Animation |
Risks
- Postoperatively, stapling
of the stomach carries
with it the risk of staple-line
disruption that can result in leakage and/or serious infection. This
may require prolonged hospitalization
with antibiotic treatment
and/or additional
operations.
- Staple-line disruption
may also, in the long-term,
lead
to weight gain. For these
reasons, some surgeons
divide the staple-line
wall of the
pouch from the rest of
the stomach to reduce the
risk
of long-term staple-line
disruption.
- The band or ring applied
may lead to complications
of obstruction or perforation,
requiring surgical intervention.
- Characteristically, these
procedures, while creating
a sense of fullness, do
not provide the necessary
feeling
of satisfaction that one
has had "enough" to eat.
- Because restrictive procedures
rely solely on a small
stomach pouch to reduce
food intake,
there is the risk of
the pouch stretching or
of the
restricting band or ring
at the pouch outlet breaking
or migrating, thus allowing
patients to eat too much.
- Around 40% of patients
undergoing these procedures
have lost
less than half their
excess body weight.
- As is the case with all
weight loss surgeries,
readmission to a hospital
may be required
for fluid replacement
or nutritional support
if there
is excessive vomiting
and adequate food intake
cannot
be maintained.

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While these operations also
reduce the size of the stomach,
the stomach pouch created is
much larger than with other
procedures. The goal is to
restrict the
amount of food consumed and alter the normal digestive process, but to a much
greater degree. The anatomy of the small intestine is changed to divert the bile
and pancreatic juices so they meet the ingested food closer to the middle or
the end of the small intestine.With the three approaches discussed below, absorption
of nutrients and calories is also reduced, but to a much greater degree than
with previously discussed procedures. Each of the three differs in how and when
the digestive juices (i.e., bile) come into contact with the food.
Since food bypasses the
duodenum, all the risk considerations
discussed in the gastric
bypass section regarding
the malabsorption of some
minerals and vitamins also
apply to these techniques,
only to a greater degree.
Biliopancreatic Diversion
(BPD)

View Illustration |
BPD
removes approximately
3/4 of the stomach to
produce both restriction
of food intake and reduction
of acid output. Leaving
enough upper stomach
is important to maintain
proper nutrition. The
small intestine is then
divided with one end
attached to the stomach
pouch to create what
is called an "alimentary
limb." All the food moves
through this segment,
however, not much is
absorbed. |
The bile
and pancreatic juices
move
through the "biliopancreatic
limb," which is connected
to the side of the intestine
close to the end. This
supplies digestive juices
in the section of the
intestine now called
the "common limb." The
surgeon is able to vary
the length of the common
limb to regulate the
amount of absorption
of protein, fat and fat-soluble
vitamins. |
Extended (Distal)
Roux-en-Y Gastric Bypass
(RYGBP-E)
| RYGBP-E
is an alternative means
of achieving malabsorption
by creating a stapled
or divided small gastric
pouch, leaving the remainder
of stomach in place.
A long limb of the small
intestine is attached
to the stomach to divert
the bile and pancreatic
juices. This procedure
carries with it fewer
operative risks by avoiding
removal of the lower
3/4 of the stomach. Gastric
pouch size and the length
of the bypassed intestine
determine the risks for
ulcers, malnutrition
and other effects. |

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Illustration |
Biliopancreatic
Diversion with "Duodenal
Switch"

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Animation |
This procedure
is a variation of BPD
in which stomach removal
is restricted to the
outer margin, leaving
a sleeve of stomach with
the pylorus and the beginning
of the duodenum at its
end. The duodenum, the
first portion of the
small intestine, is divided
so that pancreatic and
bile drainage is bypassed.
The near end of the "alimentary
limb" is then attached
to the beginning of the
duodenum, while the "common
limb" is created in the
same way as described
above. |
Advantages
- These operations often
result in a high degree
of patient
satisfaction because
patients are able to eat
larger meals
than with a purely restrictive
or standard
Roux-en-Y gastric bypass procedure.
- These procedures can
produce the greatest excess
weight
loss because they provide
the highest levels of
malabsorption.
- In one study of 125 patients,
excess weight loss of
74% at one year, 78% at
two years,
81% at three years, 84%
at four years, and 91%
at five
years was achieved.
- Long-term maintenance
of excess body weight loss
can
be successful if the
patient adapts and adheres
to a straightforward
dietary, supplement,
exercise and behavioral
regimen.
Risks
- For
all malabsorption procedures
there is a period of
intestinal adaptation when
bowel movements
can be very liquid and
frequent.
- This condition
may lessen over time,
but may be a
permanent lifelong occurrence.
Abdominal bloating and malodorous stool or gas may occur.
- Close lifelong
monitoring for protein
malnutrition, anemia
and bone disease
is recommended.As well, lifelong vitamin supplementing is required. It
has been generally observed that
if eating and vitamin supplement
instructions
are not rigorously followed, at least 25% of patients will develop problems
that require treatment.
- Changes to the intestinal
structure can result in
the increased risk
of gallstone formation and the
need for removal of the gallbladder.
- Re-routing of bile, pancreatic
and other digestive juices
beyond the
stomach can cause intestinal
irritation and ulcers.

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In recent years, better
clinical understanding of procedures
combining restrictive and malabsorptive
approaches has increased the
choices of effective weight
loss
surgery for thousands of patients. By adding malabsorption, food is delayed in
mixing with bile and pancreatic juices that aid in the absorption of nutrients.
The result is an early sense of fullness, combined with a sense of satisfaction
that reduces the desire to eat.
| According
to the American Society
for Bariatric
Surgery and the National
Institutes of Health,
Roux-en-Y gastric bypass
is the current gold standard
procedure for weight
loss surgery. It is one
of the most frequently
performed weight loss
procedures in the United
States. In this procedure,
stapling creates a small
(15 to 20cc) stomach
pouch. The remainder of
the stomach is not removed,
but
is completely stapled shut
and divided from the stomach
pouch. |

View Animation |
The outlet from this
newly formed pouch empties
directly into the lower portion
of the jejunum, thus bypassing
calorie absorption. This
is done by dividing the small
intestine just beyond the
duodenum for the purpose
of bringing it up and constructing
a connection with the newly
formed stomach pouch. The
other end is connected into
the side of the Roux limb
of the intestine creating
the "Y" shape that gives
the technique its name. The
length of either segment
of the intestine can be increased
to produce lower or higher
levels of malabsorption.
Advantages
- The
average excess weight loss
after the Roux-en-Y
procedure is generally
higher in a compliant
patient than with purely
restrictive
procedures.
- One year after
surgery, weight loss
can average
77% of excess body
weight.
- Studies show that after
10 to 14 years, 50-60%
of excess body weight loss
has
been maintained by some
patients.
- A 2000 study of
500 patients showed that
96% of certain
associated health conditions
studied (back pain, sleep apnea, high blood pressure, diabetes and depression)
were improved or resolved.
Risks
- Because the duodenum
is bypassed, poor absorption
of iron and calcium
can result in the lowering
of total body iron
and
a predisposition
to iron deficiency
anemia. This is a particular concern for patients who experience chronic
blood loss during excessive
menstrual flow or bleeding
hemorrhoids. Women, already
at risk for osteoporosis that can occur after menopause, should be aware
of
the potential for heightened bone calcium loss.
- Bypassing the duodenum
has caused metabolic bone
disease
in some patients, resulting
in bone pain, loss of
height, humped back and
fractures
of the ribs and hip bones.
All of the deficiencies
mentioned above, however,
can be managed
through proper diet and
vitamin supplements.
- A chronic anemia due
to Vitamin B12 deficiency
may
occur. The problem can
usually be managed with
Vitamin B12
pills or injections.
- A
condition known as "dumping
syndrome " can
occur as the result of
rapid emptying of stomach
contents into the small
intestine. This is sometimes
triggered when
too much sugar or large amounts of food are consumed. While generally not
considered to be a serious
risk to your health, the
results can be extremely
unpleasant
and can include nausea, weakness, sweating, faintness and, on occasion, diarrhea
after eating. Some patients are unable to eat any form of sweets after surgery.
- In
some cases, the effectiveness
of the procedure may
be reduced if the
stomach pouch is stretched and/or
if it is initially left
larger than 15-30cc.
- The
bypassed portion of the
stomach, duodenum and
segments of the small
intestine cannot be easily visualized
using X-ray or endoscopy if problems
such as
ulcers, bleeding or malignancy should occur.

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For the last decade, laparoscopic
procedures have been used in
a variety of general surgeries.
Many people mistakenly believe
that these techniques are still "experimental." In
fact, laparoscopy has become the predominant technique in some areas of surgery
and has been used for weight loss surgery for several years. Although few bariatric
surgeons perform laparoscopic weight loss surgeries, more are offering patients
this less invasive surgical option whenever possible.
When a laparoscopic operation
is performed, a small video
camera is inserted into the
abdomen. The surgeon views
the procedure on a separate
video monitor. Most laparoscopic
surgeons believe this gives
them better visualization
and access to key anatomical
structures.

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The camera and surgical
instruments are inserted
through small incisions
made in the abdominal
wall. This approach is
considered less invasive
because it replaces the
need for one long incision
to open the abdomen.
A recent study shows
that patients having
had laparoscopic weight
loss surgery experience
less pain after surgery
resulting in easier breathing
and lung function and
higher overall oxygen
levels. |
Other realized benefits with
laparoscopy have been fewer
wound complications such as
infection or hernia, and patients
returning more quickly to pre-surgical
levels of activity.
| Laparoscopic
procedures for weight
loss surgery employ the
same principles as their "open" counterparts
and produce similar excess
weight loss. Not all
patients are candidates
for this approach, just
as all bariatric surgeons
are not trained in the
advanced techniques required
to perform this less
invasive method. |

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Illustration |
The
American Society for Bariatric
Surgery recommends
that laparoscopic weight
loss surgery should only
be performed by surgeons
who are experienced in both
laparoscopic and open bariatric
procedures.

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