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Duodenal
Switch Procedure
How it Works
The duodenal switch (DS) is a newer
procedure to the United States whose concept
was originally developed by Dr. Scopinaro in
Italy. Dr. Scopinaro’s procedure is called
the Biliopancreatic Diversion or BPD. This
operation is the culmination of years of
diligent research directed by Dr. Scopinaro
and others who were aware of a segment of
morbidly obese patients who require a more
aggressive strategy for surgical weight
loss. His decades of research yielded the
BPD that is an operation not commonly
performed in the United States. (see below.)
BPD Biliopancreatic Diversion
From
health.allrefer.com/health
Dr. Hess is a bariatric
surgeon in Ohio who modified the BPD by
adding a feature that is now called the
Duodenal Switch procedure (DS). Most
bariatric surgeons in the United States
consider the DS the most aggressive of the
three weight loss procedures. The DS works
in a different manner than the Lap Band® or
the Roux-en-Y gastric bypass (RYGBP).
Whereas the Lap Band® and the RYGBP
incorporate the use of a restrictive gastric
pouch to minimize intake of calories, the DS
creates a diversion of calories away from
normal absorption. (see below.)
BPD with Duodenal Switch
From
health.allrefer.com/health
Nearly all nutrients we ingest enter our
blood system via absorption from the lining
cells of the small intestine. These lining
cells protrude into the center of the bowel
on billions of microscopic prongs called
villi. These specialized cells provide the
mechanism whereby digested nutrients such as
amino acids, fatty acids, vitamins,
carbohydrates and minerals become absorbed
and integrated into our bodies. The normal
length of small intestine in humans ranges
from 20 to 25 feet. Different sections of
the small intestine are primarily
responsible for absorbing different
nutrients.
Lining cells of the small
intestine. (from
http://arbl.cvmbs.colostate.edu)
The upper portions of the
small bowel, referred to as the duodenum and
the jejunum are primarily responsible for
absorption of proteins, minerals (like iron
and calcium) and carbohydrates (sugars and
starches). The lower portion of the small
intestine is referred to as the ileum. The
ileum is primarily responsible for absorbing
fatty acids, B12, and fat-soluble vitamins
such as Vitamins A, D, E and K.
Duodenal Switch Procedure
The primary strategy employed by the DS is
to create malabsorption by surgically
bypassing the upper 60% of the small
intestine. The fundamental concept is that
by diverting ingested food to a shorter
segment of the small intestine, fewer of the
cells lining the small intestine are exposed
to the ingested nutrients, thereby
minimizing access to these nutrients. This
translates to less absorption of calories
and nutrients regardless of meal size! The
key advantage to this procedure is that
patients are able to eat more normal-sized
meals because their ability to absorb
calories is greatly diminished. For some
patients in whom restriction is not an
attractive option (Lap Band® or RYGBP), the
DS offers an appealing alternative.
In addition to bypassing 60% of the small
intestine, malabsorption is accelerated even
further by surgically manipulating the
introduction of bile and pancreatic juices
at a point very far down stream in the flow
of the meal through the digestive tract. It
is at the beginning of the “common limb”
(see diagram below) where the alimentary
limb and the biliopancreatic limb are joined
that the ingested meal may actually begin
the process of digestion and absorption. In
essence, the final 3 feet of small intestine
known as the common limb, is the sole site
of absorption of nearly all of the ingested
fatty acids and fat soluble vitamins.
Therefore, a meal high in starch, fat or
grease may overwhelm the absorptive capacity
of the intestine leading to bloating,
cramping, foul gas and frequent malodorous
bowel movements. The optimal diet for
patients who have DS surgery is one high in
protein. Protein is rapidly digested and
absorbed throughout the digestive tract.
Patients who enjoy high protein foods like
beef, pork and fish will thrive with the DS.
Those who enjoy starches like pasta, rice,
potatoes or corn will notice foul gas and
frequent bowel movements. These are
important factors to consider when
contemplating weight loss surgery. The DS is
not an ideal option for all patients. We
tend to limit this operation to those
patients suffering severe consequences from
their morbid obesity and those with higher
BMIs. People who are severely ill with their
morbid obesity may fair better with a more
aggressive operation.
Duodenal Switch Procedure
Benefits of Surgery
The duodenal switch procedure has many
advantages. People who are well informed
understand this procedure as the most
aggressive operation. Because of the
malabsorptive component, patients are not
required to restrict intake in order to
loose weight or maintain weight loss. In
fact, as long as the diet is high in protein
and low in starch and fat, meal portions are
normal or near normal in size. There is no
portioning of food and patients seem
satisfied that they are allowed to “keep up
with everyone else at the table.” The act of
eating around holidays and celebrations can
be sustained.
Both durable weight loss and resolution of
severe comorbidities are the strengths of
the DS procedure. Patients with the most
severe obesity-related illnesses fair well
after this operation and continue to
maintain excellent weight loss years later.
Weight Loss
Weight loss after the DS is rapid.
Approximately 75% of the cumulative weight
loss after DS occurs within the first six
months. The weight loss tapers off between
12 and 18 months and rather abruptly levels
out to about 75% of excess weight. Dr. Hess
has accumulated the largest series of DS
patients in the United States. His excellent
follow up illustrates the strength of this
procedure. The steep slope of the weight
loss curve and the longevity of the
sustained weight loss are impressive. (See
graph below)
Percent of Excess Weight Loss
after DS.
Copyright ©1998 by Douglas S. Hess, MD, FACS
Percent Excess Weight Loss
after DS in Patients BMI < 50 and > 50.
Ann Surg. 2003 October; 238(4): 618–628
In the chart above, Gary J.
Anthone MD illustrates his group’s results
with weight loss in a large number of DS
patients. His experience is similar to that
of Dr. Hess, in all patients, regardless of
BMI. Notice the similarity in the rapid
weight loss over the first 6 months of the
procedure in both graphs. A weight loss
graph of Lap Band® patients is included
below for comparison.
Laparoscopic Adjustable
Gastric Banding: 1,014 Consecutive Cases
Ponce J, et al. J Am Coll Surg Vol 201, No.
4, October 2005.
Long-term weight loss after
DS and RYGBP shows a slight return to weight
gain 5 to 6 years after surgery. This is
obvious in both graphs above and is
experienced by DS patients who revert back
to ingesting moderate amounts of sugar.
Unlike RYGBP patients, DS patients do not
experience dumping syndrome related to
dietary sweets, therefore, DS patients may
notice weight regain after substantial
weight loss in earlier years due to added
sweets in their diet.
Advantages
• The most dramatic and durable weight loss
is reported in large series of DS patients
due to the malabsorptive nature of this
procedure.
• Obesity-related diseases such as diabetes,
hypertension, sleep apnea and high
cholesterol are all dramatically improved or
cured in the highest risk patients. The
recent meta-analysis of outcomes after
weight loss surgery demonstrated the highest
resolution of a majority or these illnesses
in patients who underwent DS surgery.
• Patients are able to eat more normal-sized
meals within 6 to 12 months after surgery.
Initially, the gastric ouch is about 6 oz,
however it dilates to near-normal volume
within the first year.
• Dumping syndrome is avoided after DS
because the pylorus is maintained,
preventing gastric food from dumping into
the small intestine.
Risks
• Long-term protein malnutrition occurs in 3
to 10% of DS patients resulting in wasting,
lethargy and high resistance to protein
replenishment. Often these patients will
require surgical revision or reversal of
their procedure.
• Normal bowel function is represented by 2
to 4 loose bowel movements per day.
Unhealthy eating habits will lead to 10 to
12 diarrhea bowel movements per day when
patients indulge in starches or fats such as
fried foods. Patients who enjoy diets high
in protein fair best after DS surgery.
• Poor eating habits create foul-smelling
gas, abdominal cramps, and the passage of
numerous liquid bowel movements with
under-digested food.
• Malabsorption of fats and fat-soluble
vitamins may lead to deficiencies in
Vitamins A, D, and K causing night blindness
and osteoporosis. Administering these
nutrients can reverse these deficiencies.
Complications of Surgery
Staple line leaks occur more frequently
after DS than RYGBP. The leak rate after DS
ranges from 2 to 3.5% in Dr. Hess’s
experience. The leak rate is greater after
DS because there are more potential staple
lines from which leaks may occur. The most
common place for a leak to occur is from the
long staple line along the side of the
stomach. The second most likely area for a
leak to occur is at the connection of the
duodenum to the small intestine and then
finally from the connection near the end of
the small intestine.
Where leaks occur after DS.
Leaks are dangerous when they
remain undetected. As with RYGBP, if a leak
is suspected, the patient is sent
immediately for an upper GI. A leak will be
demonstrated by oral contrast collecting out
of the stomach into the abdomen. A leak into
the abdominal cavity creates peritonitis and
if undiagnosed or untreated can be fatal.
Baptist Hospital is an ASBS “Center of
Excellence;” patients receive the diagnostic
studies they need when they need them. A
leak waits for no one: if a patient requires
an urgent upper GI, it will be ordered and
performed promptly, regardless of the hour
of the night or day of the week. Facilities
that cannot provide this level of care are
not accredited by the ASBS.
The weight limit for the fluoroscopy
machines and CT scanners at Baptist Hospital
is 450 lbs. Patients who weight more than
450 lbs are too heavy for the limits of the
scanner. Patients who weigh more than 450
lbs must understand prior to surgery that
their physicians may be at a disadvantage
because of this limitation. In these
circumstances, patients are treated
empirically; meaning therapy may be
instituted without benefit of confirming
X-ray tests.
Once a leak is discovered, immediate
treatment is mandatory. If the leak is
contained, it may be managed by placement of
a drain into the fluid collection if the
patient is not seriously ill or septic. When
a patient becomes septic, the leak has
created a serious intraabdominal infection
that must be addressed in the operating
room. Surgical control of the leak is gained
and the area washed out and widely drained.
A feeding tube is placed into the intestine
below the area of leakage to allow
administration of calories and fluids. At
times several surgeries may be required to
control the infection that may result.
Leaks can be prevented by performing leak
tests in the initial operation at the
completion of the procedure. With close
observation of the gastric staple line, blue
dye is used to fill the pouch while the
various staple lines are inspected for
leakage. If an area of dye is observed, the
area is repaired immediately with suture. A
similar test is also performed filling the
submerged gastric pouch with air; if air
bubbles are identified along the staple
line, again the area is repaired and both
tests are repeated until the pouch proves to
be both water and air tight.
Smoking and high-dose steroids interfere
with wound healing and thereby become
hazards to our patients. One must quit
smoking 60 days prior to surgery; sensitive
lab testing will be performed prior to
surgery to detect nicotine levels and assure
compliance.
Pulmonary Embolism is a blood clot
that travels to the lung is extremely rare
occurring <1% of cases. These are blood
clots that form in the deep veins of the
calves during or immediately after surgery.
They can occur after any form of surgery,
after prolonged sitting or in women who are
on hormone therapy. When the blood clots
form in the vein of the leg, they may adhere
to the wall of the vein or they may
dislodge. A dislodged blood clot will travel
with the blood flow back to the heart. The
heart then pumps returning venous blood to
the lungs where the clot will become lodged.
A large clot will essentially diminish the
lungs capacity to oxygenate blood and within
2 to 3 minutes patients can succumb.
Pulmonary blood clots are serious but rare.
It is impossible to predict which patients
are at risk; therefore all patients are
treated as if they are at risk.
Prior to surgery, patients will receive a
form of Heparin® in the holding area to thin
the blood and make it less prone to clot. In
addition, compression hose and pneumatic
pumps are applied to the calves prior to the
start of the procedure. Blood thinner
therapy and the calf compression therapy
will be continued throughout the hospital
course. Early ambulation will begin on the
night of surgery. Patients are encouraged to
walk four times a day in the hospital and at
home. Walking promotes blood flow in the
legs and decreases the risk of clot
formation.
Pulmonary emboli are suspected when a
patient becomes short of breath and the
blood oxygen level drops suddenly. A CT scan
of the chest may confirm or rule out the
possibility of a blood clot in the major
vein feeding the lungs. The treatment is
immediate transfer to an ICU, respiratory
support if needed and intravenous high-dose
blood thinner to prevent further clots and
initiate clot retraction.
The weight limit for the CT scanner is
450 lbs. Patients who weight more than 450
lbs are too heavy for the limits of the
scanner. Patients who weigh more than 450
lbs must understand prior to surgery that
their physicians may be at a disadvantage
because of this limitation. In these
circumstances, patients are treated
empirically; meaning therapy may be
instituted without benefit of confirming
X-ray tests.
Bleeding is a risk of any
intraabdominal surgery. The risk of bleeding
after DS is approximately 3%. Most bleeding
stops spontaneously, thus avoiding the need
for transfusion or return to the operating
room. Occasionally, blood transfusions may
be required, however this is unlikely.
Bleeding can occur at the various staple
lines or form blood vessles inside the
abdomen.
Complications due to anesthesia and
medications are generally caused by
reactions to the anesthetic agents.
Drowsiness, nausea and sore throat are
common effects from the anesthetic event.
The induction of general anesthesia may
precipitate heart and airway problems that
already exist. Morbidly obese patients can
have undiagnosed heart disease or sleep
apnea that manifests during or after the
procedure. Often these patients require
overnight ICU observation and may remain on
the ventilator for additional hours or days
until it is safe to allow them to breathe on
their own.
Infections in laparoscopic incisions
are rare and inconsequential. Wound
infections in the obese patient with open
surgery, however can be a serious issue
unless treated aggressively. All patients
receive intravenous antibiotics before and
after surgery to decrease the incidence of
infections. Infections on the inside of the
abdomen are much more serious. An abscess
may require operative intervention and
prolonged hospital stay. Most Intraabdominal
infections are due to contamination of the
peritoneal cavity from gut bacteria.
Marginal ulcers are ulcerations that
occur just below the pouch to small
intestine junction. They cause pain, nausea,
and may lead to a stricture if the ulcer is
chronic. Smokers are at highest risk for the
development of marginal ulcers which can
occur in about 4% of cases. Many studies
document the leading cause of ulceration in
those who begin smoking after their bypass.
These ulcers may be difficult to treat even
with routine anti-ulcer medications. Ulcers
can erode into underlying blood vessels and
cause GI tract bleeding that may require
surgical correction. Prevention is the best
medicine. Gastric bypass patients should
avoid certain medications that can cause
ulcers as Ibuprofen (Advil®), Nuprin® or
Naprosyn®.
Bowel obstruction after weight loss
surgery may be from several different
sources. Although it arises in 2.5% of
cases, the most common cause of bowel
obstruction is from internal hernias where a
portion of the small intestine can twist and
wrap around or through a space created by
the new surgical anatomy. These potential
spaces are closed at the time of surgery,
however with laparoscopic surgery,
intraabdominal scarring is sparse leaving
the small intestine more mobile. Even small
openings between layers of tissue may allow
enough room for the bowel to worm its way
and create obstruction. The diagnosis of an
internal hernia may be difficult as internal
hernias may be intermittent and undetectable
on CT scanning. The treatment is
laparoscopic exploration and closure of the
defect with permanent suture.
Internal hernia after RYGBP.
CT scan of internal hernia, trapped bowel in
white.
Nutrient deficiency
may be a serious consequence of this
malabsorptive operation. It has been
estimated that up to 30% of patients may be
iron or calcium deficient after duodenal
switch. Patients who are considering this
operation must understand they are mandated
to take supplemental vitamins, calcium and
iron every day for life. The duodenum is the
portion of the small intestine where
calcium, iron and B12 are preferentially
absorbed. Because the duodenum is no longer
in the stream of food flow, DS patients
become susceptible to vitamin and nutrient
deficiencies that lead to anemia,
osteoporosis and lethargy. Hence, routine
blood work is required on an annual basis to
assess vitamin and nutrient levels.
Long-term follow up is mandatory as most
patients become less compliant with
medications after surgery; as their co
morbid conditions diminish, they become
accustomed to taking fewer and fewer
medications.
In addition, protein malnutrition occurs in
3 to 10% of patients after DS surgery. It is
imperative that DS patients maintain at
least 80 grams of daily protein intake to
accommodate the relative malabsorptive
state. Patients who ignore or forget the
strict need to maintain high protein intake
are at risk for debilitating malnutrition.
For this reason and more, the DS must be
considered only in those patients who have
the motivation and the means to understand
this basic concept. Even when patients are
compliant with proper dietary habits,
although less likely, protein malnutrition
may still occur and may be cause for
long-term intravenous nutritional therapy.
Failing this, surgical revision by
lengthening the alimentary limb may be
necessary. The malabsorptive effects of the
DS can be surgically reversed.
Diet after Surgery
Patients are required to stay on liquids for
3 days after surgery followed by purée diet
for 2 weeks. During this period, water is
essential to maintain hydration. After 2
weeks, patients are allowed to begin eating
regular food in small portions choosing
foods that are light and soft. After several
months, the elasticity of the stomach tube
will allow patients to ingest greater
amounts of food and greater proportions of
protein. Meals should be prepared as usual
and patients should concentrate on filling
up on proteins first. Proteins are the
staple of the DS. High protein diets include
beef, pork, fish, legumes, tofu, and
vegetables. Starches and fats will create
gas, cramping and diarrhea. Prolonged
diarrhea occurring months after surgery may
result form over utilization of antibiotics.
Overgrowth of yeast may lead to severe
diarrhea that can be managed on an
intestinal restoration protocol.
The intestinal protocol calls for several
interventions:
Elimination Diet
No Sugar – use Splenda®
No white flour, corn four, or white rice products
No fruit
No dairy products
Foods Allowed
Meats, vegetables
Brown rice, oats, whole crack wheat
Yeast-free breads that contain no
white flour
Pro-Boitics
Pro-Biotics are pills that contain friendly bacteria or
bacteria parts. Primal Defence® is a branded
pro-biotic that resists stomach acid and
bile. Take on an empty stomach as follows:
Week one – one pill per day
Week two – two pills per day
Week three – three pills per day
If diarrhea persists, anti-fungal
medications may be necessary.
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