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Obesity
is a complex disease influenced by the interaction
of several genetic, endocrine, metabolic and enviromental
factors. It has gained epidemic proportions in
India, with nearly 120 million of the adult population
affected. With obesity comes an array of debilitating
and life-threatening comorbidities including adult-onset
diabetes mellitus, hypertension, hypercholesterolemia,
sleep apnea syndrome, cholelithiasis, cardiovascular
disease, renal disease, osteoarthritis, psychosocial
problems and an increased risk of uterine, colon,
and breast cancer.
The method
of defining the relationship between body weight
and frame size is the body mass index (BMI). Obesity
is defined as a BMI of greater than 30kg/m2. The
1991 National Institutes of Health (NIH) Consensus
Panel defined morbid obesity as a BMI of 35kg/m2
or more with obesity related comorbidities or
40 kg/m2 without comorbidities. Super-obese patients
are defined as having a BMI of 50 kg/m2 or greater.
Other definition of morbid obesity includes patients
who weigh at least 200% of their ideal body weight.
No dietary
approach has achieved long-term success for treating
morbid obesity. Several weight-reducing agents
including, currently available Sibutramine and
orlistat are associated with only a 10% weight
loss in most studies. Surgery has been the only
method proven effective in maintaining long-term
weight loss, with current options including restrictive,
malabsorptive or a combination of both procedures.
The restrictive procedures decreases food intake
by creating a small upper stomach pouch to limit
food intake i.e. laparoscopic adjustable gastric
banding (LAGB). The malabsorptive procedure alter
digestion, thus causing the food to be poorly
digested and incompletely absorbed i.e. Laparoscopic
Biliopancreatic Diversion with duodenal switch
(BPD with DS). There are procedures that combine
the restrictive and malabsorptive mechanism of
weight loss surgery i.e. laparoscopic Roux-en-Y
gastric bypass (LRYGBP). It must be remembered
that an effective bariatric procedure is one that
results in a sustained excess weight loss (EWL)
of greater than 50% and resolution of comorbid
conditions.
Laparoscopic
surgical techniques have dramatically evolved
over the last two decades and have created a worldwide
revolution in the field of bariatric surgery.
Although laparoscopic techniques have progressively
replaced the open approach to bariatric surgery,
great disparity exists regarding the preferred
procedure around the world. The gastric bypass
and duodenal switch currently represent nearly
80% to 90% of laparoscopic bariatric procedures
in the United States and Canada, whereas laparoscopic
gastric restrictive procedures still represent
the majority of bariatric procedures performed
in Europe. Several reasons may explain this disparity;
most important of all, different dietary habits
and lower BMI (35 to 50 kg/m2) in European patients
may explain the potential for a better response
to gastric restrictive procedures. This is in
contrast to the United States population, in which
a higher BMI among patients is more common. Gastric
restriction typically fails in these super-obese
patients, and malabsorptive bariatric procedures
remain the mainstay of surgical treatment in this
group.
LAPAROSCOPIC
ADJUSTABLE GASTRIC BANDING (LAGB)
The procedures require banding of the upper stomach
via placement of an adjustable silicone band to
achieve a sensation of satiety with small meals.
The method of LAGB placement has evolved into
the pars flaccida technique. Principles of the
pars flaccida technique include the creation of
a very small proximal pouch (15ml), posterior
dissection just below the crura above the reflection
of the bursa omentalis, improved anterior suture
fixation of the fundus and anterior gastric wall
over the band, and complete deflation of the low
pressure band at the time of placement. The port
is attached to the tubing, excess tubing is passed
into the peritoneal cavity, and the port is secured
to the anterior rectus sheath with permanent sutures.
The restrictive
procedures usually are simple, technically easier
with low complication rates. The lap band procedure
may not be the best surgical option in certain
patient subgroups, including super-obese patients,
diabetics, patients with hiatal hernia or significant
gastroesophageal reflux disease. The combination
of proper surgical technique, restricted diet,
patient cooperation, and close patient follow-up
with frequent band adjustments performed in a
comprehensive bariatric program setting may make
this device an effective surgical treatment of
morbid obesity.Under these conditions, an excess
weight loss of 50 - 65% can be anticipated.
LAPAROSCOPIC
ROUX-EN-Y GASTRIC BYPASS (LRYGBP)
The Roux-en-Y gastric bypass (RYGBP) was first
described by Mason nearly 30 years ago, and it
is the gold standard bariatric procedure. This
RYGBP is constructed using a small 15 to 20mL
gastric pouch and a Roux-en-Y gastrojejunostomy.
This procedure creates malabsorption by bypassing
the distal stomach, proximal duodenum, and a variable
length of the jejunum depending on the length
of the Roux limb. A Roux limb length between 50
and 100cm appears to be preferred by most surgeons
with similar results. Improved weight loss in
super-obese patients without significantly greater
morbidity can be obtained utilizing a 150cm Roux
length. Antecolic placement of the Roux limb appears
equally as safe as the retrocolic position with
a lower risk of internal hernia formation. The
Linear stapler anastomosis (LSA) can be performed
more expeditiously than the Hand-sewn anastomosis
or Circular stapler anastomosis (CSA).
The data
suggest the superior weight loss benefits in RYGBP
patient without the long-term sequelae of band
erosion, reflux and vomiting. Most of the nutrient
and vitamin deficiencies caused by the gastric
bypass (iron deficiency anemia and vitamin B12
deficiency) were correctable with vitamin supplementation.
In addition, the altered anatomy reliably produces
altered gut absorption leading to symptoms of
dumping syndrome in response to high-calorie sweets
intake. This likely remains an important difference
from pure gastric restriction and explains some
of the greater weight loss. Laparoscopic Roux-en-Y
gastric bypass in most clinical series have demonstrated
excess weight loss (EWL averaging between 65 -
85%).
LAPAROSCOPIC
BILIOPANCREATIC DIVERSION WITH DUODENAL SWITCH
(BPD WITH DS)
Although the BPD continued to be a successful
bariatric procedure producing adequate weight
loss in most clinical seires, several complications
including marginal ulceration, diarrhea, and protein
calorie malnutrition were seen more commonly than
in gastric bypass patients. A modification to
the BPD with a duodenal switch consisting of a
sleeve gastrectomy and a duodeno-ileostomy proposed
by Hess and Marceau appeared to reduce the incidence
of these complications. Their common channel was
50 to 100 cm in length, whereas the alimentary
limb measured variably from 225 to 350 cm. Their
results were excellent, with reportedmean EWL
of 80% at 2 years and 70 % at 8 years. Overall,
BPD with or without duodenal switch appears to
be a very effective weight loss procedure for
the super-obese (BMI greater than 50) with improvement
in diabetes, hypertension, hyperlipidemia, and
obstructive sleep apnea. These patients should
be followed closely and aggressive vitamin and
mineral supplementation should be performed.
LAPAROSCOPIC
SLEEVE GASTRECTOMY (SG)
Bariatric surgery is technically difficult in
super obese and should be cautiously applied in
BMI greater than 60 kg/m2, and high risk individual.
Sleeve gastrectomy or a two staged procedure i.e.
SG + LRYGBP or SG + BPD - DS is an emerging option,
as it reduce the risk and yet achieve satisfactory
weight loss in super morbidly obese. In Sleeve
gastrectomy greater curvature gastrectomy is done
with starting point 6cm from pylorus, along a
32 Fr bougie to form a 60-80 cc gastric tube.
No long term nutritional deficiency and dumping
is there, as no intestinal bypass is done and
pylorus is preserved. Long term results are awaited.
SUMMARY
Several bariatric procedures are available that
have excellent long-term weight loss results and
are backed by several large clinical trials. Purely
restrictive procedures like LABG is ideal to occasional
female treatment - compliant individual with a
BMI below 45 and a normal Lower oesophageal sphincter,
who may be a sweet eater. VBG have fallen out
of favour because of inadequate long-term weight
loss. Gastric bypass and the BPD are well-studied
and show significant resolution of obesityrelated
comorbidities. Long-term nutritional consequences
are seen more commonly after malabsorptive procedures
i.e BPD than after hybrid malabsorptive-restrictive
procedure i.e gastric bypass. Because compliance
and long-term nutritional follow-up are mandatory
after any bariatric procedure, purely malabsorptive
procedures should be reserved for superobese patients
who are at risk for inadequate longterm weight
loss. For super obese and high risk patient sleeve
gastrectomy is an emerging promising option. Furthermore,
minimally invasive techniques have evolved and
essentially have eliminated the high incidence
of postoperative wound complications and incisional
hernias frequently seen after open procedures.
Until the development of a similarly successful
procedure, gastric bypass will continue to be
the gold standard bariatric procedure with its
concurrent sustained weight loss benefits and
resolution of comorbidities. |
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