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Bariatric Surgical Procedures
Bariatrics deals with the causes, prevention, and treatment of obesity. Bariatric surgery, also known as weight loss surgery, refers to the various baroatric surgical procedures performed to treat obesity by modification of the gastrointestinal tract to reduce nutrient intake and/or absorption.
Introduction to
Bariatric Surgery
Bariatric Surgery is a unique field, in that with one
operation, a person can be potentially cured of numerous medical diseases
including diabetes, hypertension, high cholesterol, chronic
headaches, liver disease, sleep apnea and
arthritis.
Bariatric Surgery is the only proven method that results in durable weight loss.
It avoids the normal failure of dieting. It is a proven surgical approach. The quick recovery with minimally invasive
(Laparoscopic) techniques, has increased significant the number of bariatric procedures
performed during the last 10 years.
Bariatric surgical procedures can be divided into three kinds:
1. Restrictive procedures decrease food intake and promote a feeling of fullness
after meals.
2. Malabsorptive procedures reduce the absorption of calories, proteins and
other nutrients.
3. A combination of both restrictive and malabsorptive procedures
Most bariatric procedures can be performed through "open" or "laparoscopic" surgery.
The primary procedures most used
for weight loss are:
- Open Gastric Bypass (combination of restrictive and malabsorptive
procedures)
- Laparoscopic Gastric Bypass (combination of restrictive and malabsorptive
procedures)
- Laparoscopic Adjustable Gastric Banding - LapBand (restrictive procedure)
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Gastric Bypass - Restrictive and
Malabsorptive Bariatric Procedure
Gastric Bypass procedure was developed in the 1960s. The gastric bypass was developed after the weight loss
was observed among patients undergoing partial stomach removal for ulcers.
1.
Loop Gastric Bypass - later called the Mini Gastric Bypass (MGB)
The first gastric bypass was in 1967, It used a loop of the small bowel for
re-construction. Although simple to create, it allowed corrosive juices from the
small bowel to enter the gastric pouch, sometimes causing severe inflammation
and ulcers. It was abandoned but recently re-employed by a few surgeons, as
the "Mini-Gastric-Bypass", mainly to simplify the reconstruction, when performed
laparoscopically. Although the mini gastric bypass has a low complication rate,
there are now multiple reports in the medical literature of serious long-term
complications with the procedure, even requiring revision surgery.
2.Proximal Roux-en-Y
Gastric Bypass (RYGBP)
Over several decades, the gastric bypass has been modified into its present form,
using a Roux-en-Y limb of intestine connected to a very small stomach pouch which prevents the bile from entering
the upper part of the stomach and esophagus. The remaining stomach and
first (proximal) segment of small intestine are bypassed. The
Y-intersection is formed near the upper end of the small bowel. The Roux limb is
constructed with a length between 30 to 60 inches, preserving most of the small
bowel for absorption of nutrients. The patient gets quickly a sense of
stomach-fullness, followed by a satiety feeling, shortly after the start of a
meal.
The Proximal Roux-en-Y Gastric Bypass (RYGBP) has been the most
commonly performed operation for weight loss. Approximately 140,000 gastric
bypass procedures have been performed in 2005 in the USA alone. The Roux-en-Y Gastric Bypass outnumbers all other procedures and results.
The amount of intestine bypassed is not enough to create malabsorption of protein or other macronutrients.
However, because the bypassed portion of intestine is where the majority of
calcium and iron absorption takes place, lifelong mineral supplementation is mandatory.
The Gastric Bypass has been proven in numerous studies to result in durable weight loss and
improvement in weight-related medical illnesses. Half of the weight loss often
occurs during the first 6 months after surgery; the weight loss is peaking after
18-24 months. The Gastric Bypass has resulted in marked improvements in quality of life.
The obesity-related illnesses that may be improved or cured after
Gastric Bypass surgery include diabetes type II, hypertension, high
cholesterol, arthritis, venous stasis disease, bladder incontinence, liver
disease, certain types of headaches, heartburn, sleep apnea and many other
disorders.
3.
Distal Roux-en-Y Gastric Bypass
As the Y-connection is moved farther down the Gastro intestinal tract, the
amount of the bowel capable of fully absorbing nutrients is reduced. The
Y-connection is made closer to the lower (distal) end of the small bowel,
usually 40 to 60 inches from the lower end of the bowel, causing reduced
absorption of food, mainly fats and starches, but also various minerals, and
fat-soluble vitamins. The unabsorbed fats and starches pass into the large
intestine, where bacterial action produces often irritants and malodorous gases.
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Laparoscopic Gastric Bypass
(RYGBP) - Restrictive and Malabsorptive Bariatric Procedure (Franco e Rizzi's surgical
specialty)
Although the open proximal RYGBP (described above)
can be performed with low morbidity and mortality, the wound-related
complications such as infection and incisional hernia can be troublesome. Wound
infection occurs in as many as 8% of patients after open Gastric Bypass and late
incisional hernia occurs in as many as 20% of patients. The laparoscopic
approach to Gastric Bypass reduces the postoperative complications arising from
a large incision in a obese patient.
In 1994 the first series of
laparoscopic Gastric Bypass were performed. The primary differences between
Laparoscopic and Open Gastric Bypass are the method of access and method of
exposure. Laparoscopic Gastric Bypass is performed through 5 to 6 small
abdominal incisions (0.5-2.0 cm) and the abdomen is insufflated with carbon
dioxide gas to create space to work. In contrast, Open Gastric Bypass is
performed through a larger incision and abdominal wall retractors to create
space to work. By reducing the size of the surgical incision and the trauma
associated with the operative exposure, the surgical insult has been shown to be
much less after laparoscopic surgery compared to open Gastric Bypass. A
limitation of the laparoscopic approach is the steep learning curve of this
technically challenging procedure for the surgeon, so it is not an operation for
the surgeon who has not been trained specifically in this laparoscopic surgery technique.
Advantages of Laparoscopic RYGBP compared to Open RYGBP:
- Lesser operative blood loss
- Shorter hospitalization
- Reduced postoperative pain
- Less pulmonary complications (atelectasis)
- Faster recovery
- Better cosmesis
- Fewer wound complications (incisional hernias and infections)
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Silastic Ring Gastric Bypass -
Restrictive and Malabsorptive Procedure
The Silastic® ring gastric bypass is a banded pouch RYGBP. A Silastic® ring is placed around the
vertically constructed gastric pouch above the anastomosis between the pouch and
intestinal Roux limb. The band controls stomach size by prevention of dilatation
of the gastric pouch outlet, and is thought to provide better long-term control
of the rate of emptying of the pouch and caloric intake. This procedure also
includes placement of a gastrostomy tube for decompression of the distal
stomach. A radio-opaque ring marker may be placed around the gastrostomy site to
facilitate future percutaneous access to the distal stomach. A small percentage
(5%) of patients may have band erosion or obstruction, necessitating surgical
band removal.
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Biliopancreatic diversion (BPD) -
Malabsorptive procedure
The biliopancreatic diversion (BPD) is a safer malabsorptive alternative to
the jejunoileal bypass (JIB) developed in the 1950's. This operation induces
controlled malabsorption without many of the potential side effects caused by
bacterial overgrowth associated with the JIB.
Unlike the Gastric Bypass where no stomach is removed (only bypassed), the BPD involves the
removal of 70% of the stomach. Of note, the portion of the remaining upper stomach is far larger than the small
“pouch” created for the RYGBP. This allows patients to eat larger volumes than
after a restrictive operation before feeling full (satiety). After entering the
upper stomach, food passes through a newly created connection (anastomosis) into
the small intestine (alimentary limb). This anatomy is very similar in principle
to the standard RYGBP, except that the length of the intestine from the stomach
to the colon is much shorter – promoting malabsorption. Surgeons use various formulas to determine the
appropriate length of the alimentary channel and the common channel.
Being a malabsorption operation, the BPD requires also life-long medical follow-up.
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Duodenal switch (DS) - Malabsorptive
procedure
The duodenal switch (DS) is a modification of the BPD designed to prevent ulcers, increase the amount of
gastric restriction, minimize the incidence of dumping syndrome, and reduce the
severity of protein-calorie malnutrition. However, the dumping syndrome is also
believed by many to be a benefit, rather than a detriment, in that it helps
patients avoid eating sugary and high fat foods which would adversely affect
weight loss.
The DS works through an element of gastric restriction as well as malabsorption. The
stomach is fashioned into a small tube, preserving the pylorus, transecting the
duodenum and connecting the intestine to the duodenum above where digestive
juices enter the intestine. Compared to the BPD, the DS leaves a much smaller
stomach that creates a feeling of restriction much like that of a Gastric
Bypass. Anatomically, the main difference between the DS and the BPD is the
shape of the stomach – the malabsorptive component is essentially identical to
that of the BPD. Instead of cutting the stomach horizontally and removing the
lower half (such as with the BPD), the DS cuts the stomach vertically and leaves
a tube of stomach that empties into a very short (2-4 cm) segment of duodenum.
The duodenum is tolerant of stomach acid and therefore is much more resistant to
ulceration compared to the small intestine. Removing part of the stomach also
decreases the amount of acid present. Whereas the BPD involves an anastomosis
(connection) between the stomach and the intestine, the DS involves an
anastomosis between the duodenum and the intestine. The duodenum is cut about
2-4 cm from the stomach (measured from the pyloric valve). The intestine is sewn
to the end of the duodenum which remains in continuity with the stomach. The
other side of the duodenum will carry all the bile and pancreatic secretions. A
theoretical (but clinically unproven) benefit of the DS is an improvement in
absorption of iron and calcium in comparison to the BPD. The disadvantage of
transecting the duodenum is the large number of vital structures immediately
adjacent to the duodenum. Several large blood vessels and the major bile duct
are located here. Injury to these structures can be life-threatening.
The DS and BPD procedures have high reported weight loss in long-term studies,
but also have the highest rate of nutritional complications compared to the RYGBP and the purely restrictive procedures. These
two operations are some of the most complex in bariatric surgery.
Both the BPD and the DS can be performed laparoscopically. However, these operations are
more demanding technically than the RYGBP and should only be performed in the
most experienced hands.
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Gastroplasty (HG and VBG) -
Restrictive Procedure
The gastroplasty (developed in the early 1970s)was designed to be a safer alternative to the RYGBP and the JIB/BPD.
The operation itself was made possible by the introduction of mechanical
staplers. The Horizontal Gastroplasty (HG) was the first purely restrictive
operation performed for the treatment of obesity. The
stapling the stomach into a small partition – and only leaving a small opening
for food to pass from the upper stomach pouch to the lower one, created the term: stomach stapling. This form of gastroplasty resulted in very poor long-term
weight loss and, after several attempted modifications, was abandoned
eventually.
The Vertical Banded Gastroplasty (VBG) features a pouch based on the lesser
curvature of the stomach and a polypropylene mesh band or Silastic® ring around
the outlet of the pouch. The advantages of the VBG include a lower mortality rate
and the virtual absence of micronutrient deficiencies.
However, once a popular surgical option for obesity, the VBG is performed less frequently, because studies have shown a prominent rate of weight regain or exacerbation of severe heartburn. Trials have demonstrated superior weight loss with Gastric Bypass compared to VBG. Weight loss for sweets eaters has been shown
also to be superior with RYGBP.
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Gastric Banding (GB) - Restrictive Procedure
Another example of a purely restrictive bariatric procedure is the nonadjustable gastric banding. Introduced in 1978 by Wilkinson, a 2 cm Marlex mesh
was applied around the upper part of the stomach to separate the stomach into a small upper pouch and
a larger bottom pouch. Eventually pouch dilatation resulted in unsatisfactory weight
loss.
Later in1980, Molina described the gastric segmentation procedure, in which a Dacron vascular
graft was placed around the upper stomach. The gastric pouch was smaller than
Wilkinson’s procedure. Because the Dacron graft produced adherence of the liver
to the band, it was replaced ultimately by PTFE (Gortex®).
Kuzmak began using in 1983 a 1 cm Silicone® band to encircle the stomach, creating a 13
mm stoma and a 30-50 mL proximal gastric pouch.
Advantages of gastric banding:
- Absence of anemia
- Absence of dumping
- Lack of malabsorption
- Short hospital stay
- Very low mortality rate
Complications of gastric banding
- Gastric perforation
- Incisional hernia
- Stomal stenosis
- Band slippage
- Band erosion into stomach
- Need for reversal or revision
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Laparoscopic Adjustable
Gastric Banding (LAGB) - Restrictive Procedure
Kuzmak further developed the Gastric Band in 1986 using a Silicone band lined with an inflatable balloon. This balloon was connected to a small reservoir that is placed under the skin of the abdomen through which the diameter of the band can be adjusted.
Inflation of the balloon tightens the band and increases weight loss, while deflation loosens the band and reduces weight
loss. These bands can be inserted laparoscopically, thereby reducing the complications and discomfort of an open procedure.
The Gastric Banding procedures do not involve an intestinal bypass and induces weight loss solely through the restriction of food
intake. For optimal results, strict patient compliance and frequent follow-up
for band adjustments are required. LAGB is a reversible procedure that does not
carry the risks of nutritional and mineral deficiencies of other bariatric
procedures.
Excess weight loss with the laparoscopic adjustable gastric band is lower than that with the
gastric bypass or malabsorptive procedures.
Advantages of LAGB
- Same as gastric banding
- Adjustability of the band
- Reversibility (by band removal)
- Laparoscopic placement
Complications after LAGB:
Intraoperative:
- Hemorrhage
- Injury to the spleen, stomach, or esophagus
- Conversion to open procedure
Postoperative:
- Band slippage (stomach prolapse)
- Leakage of the balloon or tubing
- Port Infection
- Band infection
- Obstruction
- Nausea and vomiting
Late complications:
- Band erosion into the stomach
- Esophageal dilatation
- Failure to lose weight
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Intragastric Balloon
The intragastric balloon is a silicone prosthesis of spherical format and has a smooth surface. It is
introduced into the patient's stomach by an endoscopic procedure, in general
there is no need for hospitalization. The risks of complication are low. The
mean dwelling time of the balloon in the stomach is from 4 to 6 months. This
technique is primarily used for reducing weight in very obese patients (mean of
10-15 kg), who should first lose weight in order to undergo the gastric bypass
surgery. It might be used in the less obese who wish to lose weight, and in the
obese who do not wish to undergo surgery.
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What is next?
There are other procedures are in development. A
implantable gastric stimulation device with small electrodes
is attached to the stomach and gives a feeling of fullness when stimulated electrically. The intragastric balloon is
now being re-introduced
as a simple procedure that can be placed through an endoscope. The balloon will “take up space” and thereby decrease the amount of food patients can
eat. Both of these simple procedures do not have yet documented adequate long-term weight loss. However,
they may have an important role
in the future.
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Summary
Almost all above described bariatric surgery procedures have resulted in consistent short-term weight loss. Unfortunately
there is no perfect operation. The remarkable drive for the obese patient to
regain weight cannot be eliminated in all patients. Furthermore, the history of
weight loss surgery repeats itself with procedures that seemed initially to be very
promising and safe in theory, but which were later found to be failures. As
such, newer procedures should always be viewed with caution. The RYGBP (and also LAGB, DS
and BPD) have withstood appropriate scrutiny through well documented results. The Roux-en-Y Gastric Bypass outnumbers
all other procedures and results and count almost for 80% of all bariatric surgeries performed worldwide.
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RISK OF BARIATRIC
SURGERY
Any major surgery involves the potential for
complications - adverse events which increase risk, hospital stay, and
mortality. Some complications are common to all abdominal operations,
while some are specific to bariatric surgery. A person who chooses to
undergo bariatric surgery should know about these risks.
BARIATRIC SURGICAL
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