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.
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.
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.
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.
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.
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.
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. 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.
