The United States of America has experienced a steady rise in obesity over the last 20 years and currently ranks second in the world. At the turn of the millennium, nearly two-thirds of Americans were overweight or obese, and almost 5% were morbidly obese. Morbid obesity predisposes patients to co-morbid diseases which affect nearly every organ system. These include: type 2 diabetes, cardiovascular disease, hypertension, hyper-lipidemia, hypoventilation syndrome, asthma, sleep apnea, stroke, pseudo-tumor, arthritis, several types of cancers, urinary incontinence, gallbladder disease, and depression. Obesity shortens life expectancy, with increasing body mass index (BMI) resulting in proportionally shorter lifespan. With over 300,000 victims in the United States each year, morbid obesity is projected to overtake smoking as the leading cause of death in the near future.
Surgically induced weight loss is associated with resolution or
improvement of
co-morbid diseases
in 75–100% of
patients, and
reduced mortality
compared with
medically treated
patients.
Weight-loss surgery
is the most
effective treatment
for morbid obesity,
producing durable
weight loss,
improvement or
remission of
co-morbid
conditions, and
longer life (level
I, grade A).
Operations to alter
weight have been
performed for years,
however, some
mal-absorptive
procedures led to
morbidity and
mortality related
bacteria over growth
and liver damage.
The goal of surgical weight loss procedures in general is to either
reduce the amount of
consumed calories
(restrictive) per
day or to alter the
absorption of the
fat (mal-absorption)
in the food one
consumes. There are three widely recognized categories of weight loss
surgery:
• Restrictive operations
• Primarily mal-absorptive procedures with some
restriction
• Primarily restrictive procedures with some
mal-absorption
Restrictive procedures include:
• Vertical banded gastro-plasty (VBG)
• Laparoscopic Adjustable Gastric Banding (LAGB)
This
group of procedures
reduces the
effective capacity
of the patient’s
stomach. By placing
a band or
constrictive device
like a belt around
the very top portion
of the stomach, the
passage of food from
the upper stomach to
the lower stomach is
delayed. A patient
will feel full
quickly and stop
eating after
smaller portions
each meal.
The food will
eventually pass from
the upper stomach to
lower stomach, and
from there will pass
through the normal
digestive tract.
Henceforth, there is
no mal-absorption
effect.
The adjustable band
(LAGB) can be
tightened according
to the patient’s
appetite and feeling
of satiety with
small portions. If
the patient
experiences frequent
hunger and is eating
large portions, the
band can be
tightened; this
results in lessening
of appetite and
increased
restriction. Band
tightening can be
done either in the
doctor’s office or
in the radiology
department.
Because volume of
food intake is
reduced overall,
nutritional
deficiencies may
occur. Therefore, it
is recommended that
these patients take
a complete
multivitamin daily.
However, if too
little food is being
consumed and the
patient becomes
underweight, for
example in
pregnancy, the band
can be loosened to
allow for more
nutritional intake.
Primarily
Mal-absorptive
Procedures with Some
Restriction
•
Bilio-pancreatic
Diversion (BPD)
•
Bilio-pancreatic
Diversion with
Duodenal Switch (DS)
This group of
procedures produces
weight loss
primarily through
mal-absorption.
There is a minor
restrictive effect
because of some
reduction in the
size of the
patient’s stomach,
but relative to the
mal-absorption
effect this is
minimal.
There are two
mechanisms by which
the mal-absorption
effect is created.
First, the food is
rerouted so that
approximately 60% of
the small intestine
(the primary site
for the absorption
of nutrients) is
bypassed. This means
that food is in
contact with the
absorptive surface
of the intestine for
less time, thereby
leaving less
opportunity for the
nutrients to be
extracted in by the
body. Second, by
virtue of this food
rerouting, there is
less mixing with
bile and pancreatic
enzymes. The mixing
of bile and
pancreatic enzymes
with food after this
type of surgery
occurs in only 10%
of the most distal
small intestine.
Therefore, only a
small amount of
protein and fat are
efficiently
absorbed.
Primarily
Restrictive
Procedures –with
Some Mal-absorption
• Roux-en-Y Gastric
Bypass (RNYGBP)
• Vertical Banded
Gastric Bypass
Gastric bypass
procedures produce
weight loss
primarily by gastric
restriction,
combined with an
element of
mal-absorption. A
small gastric pouch
is created at the
upper normal
stomach. This small
pouch (less than 1
ounce immediately
following surgery)
results in a
significant
reduction in the
amount of food a
patient can consume
in one sitting. Then
ingested food
bypasses the rest of
the stomach, the
entire duodenum
(first portion of
the small
intestine), and a
short segment of
jejunum (second
portion of small
intestine). This
bypass results in
mild fat and protein
mal-absorption due
to a slight delay in
mixing of food with
bile and pancreatic
enzymes.
These alterations in
the intestinal tract
create challenges to
maintaining healthy
levels of certain
nutrients including
protein, vitamins,
and minerals.
Calcium and Iron
deficiencies can
occur as well.
Frequent loose
stools can
potentially be a
side-effect of
mal-absorption
procedures. Since
this can increase
the risk of
dehydration,
patients need to be
monitored carefully.
Click here for a
guideline for
potential surgical
post-op
complications:
With the trend of
increased obesity
and bariatric
surgery, is your
facility and staff
prepared to care for
the needs of these
patients both short
and long term?
Do you have
the policies,
guidelines,
education and tools
to accommodate this
rapidly growing
patient population?
For more information
contact Pathway
Health Services.
References:
ASBS
Public/Professional
Education Committee
-
May 23, 2007
Revised February
7, 2008
American
College
of
Surgery
