In
order to understand how bariatric surgery results in weight loss, it is necessary to understand how food is digested (Figure
1) - After swallowing, food enters the stomach, which acts to hold the food and then allow small amounts of the food
to pass further into the digestive tract. The volume of the stomach is usually between 600 - 1000 cc (20 - 30 oz.)
- In
the first part of the small bowel (duodenum), food comes into contact with bile, secreted by the liver as well as enzymes
from the pancreas. These secretions help in the digestion and absorption of food. The small bowel is where most of the absorption
of food occurs and may reach a length of 6 - 7 meters (over 20 feet). The proximal (closest to the mouth) two-fifths of the
small bowel is called the jejunum and the distal (farthest from the mouth) three-fifths is called the ileum
Most
bariatric procedures work by two methods - a restrictive component and a malabsorptive component - Restrictive component
- a portion of the stomach may be removed or bypassed so as to reduce the volume of the stomach. Thus, only a limited amount
of food can be eaten prior to getting full
- Malabsorptive component - Bile and pancreatic secretions, which are necessary
for digestion of food, are directed away from the food. These secretions reach the food several yards down the length of the
small bowel, thus delaying and causing incomplete digestion and absorption of the food
Who is at risk?
GERD is a common disease with nowell-identified risk
factors. Dietary factors that may exacerbate GERD include caffeine, chocolate, and acidic foods such as tomatoes and orange
juice. Lifestyle factors such as eating in a lying position and falling asleep soon after eating can also exacerbateGERD.
How is it diagnosed?
There are a number of diagnostic studies used to establish a diagnosis of GERD. The best study to
determine if reflux episodes are occurring and how often is a 24 hour pH probe. pH is a measure of how acidic a fluid is.
A small flexible tube is inserted into the nose down into the stomach. A sensor at the end of the tube measures how often
over the 24 hours the pH reading is less than 4. (The lower the reading, the higher the acidity.) Patients are also asked
to keep a daily diary of reflux symptoms to see how well these correlate with the presence of acid in the esophagus.
Endoscopy is another common study used to diagnose GERD. Endoscopy involves placing a flexible tube with a
camera at its end down into the stomach through the mouth. Endoscopy allows complete visualization of the esophagus and stomach
enabling your doctor to assess for damage due to reflux such as esophagitis or gastritis. Endoscopy can also diagnosis a reflux
stricture - narrowing from repeat bouts of inflammation, healing, and then scarring.
Still
another study which gives information similar to that provided by an endoscopy is an Upper GI series or barium swallow. This
involves the drinking of barium, a liquid which lights up on x-ray, by the patient. After the patient drinks the barium, a
series of xrays are taken of the esophagus which appears lighted up from being coated with barium. The upper GI can show the
acid reflux as well as display any scarring or inflammation that my have resulted from years of reflux. An UGI can diagnose
the presence of a hiatal hernia which basically means the stomach, instead of staying down in the abdomen, will occasionally
migrate up into the chest through a too large opening in the diaphragm. While an upper GI or barium swallow can give similar
information to an endoscopy, endoscopy is the only study that allows for biopsies to be taken.
Since
poor peristalsis of the esophagus can affect how effective surgery is, some surgeons will recommend performing a study called
esophageal manometry to study how well the patient's esophagus contracts. This involves placing a small flexible tube into
the nose and down the esophagus. This tube has a sensor at its tip that measures the pressure exerted on it in the various
segments of the esophagus.
How do I prepare for surgery?
In addition to the diagnostic studies listed above, your doctor
will want you to obtain some blood work prior to surgery. The blood work required is usually a complete blood count, a chemistry
panel, and bleeding studies. An EKG and CXR will likely be required to assess your overall risk of developing a complication
from general anesthesia if you are over the age of 40.
How
is the surgery performed?
A procedure called fundoplication
is performed to reinforce the LES, allowing it close off the esophagus when the stomach is full to prevent regurgitation of
acid into the stomach. The uppermost part of your stomach, the fundus, is partially wrapped around the lower aspect of your
esophagus. When the stomach distends with food, it puts pressure against the lower aspect of the esophagus closing it off
to prevent entry of acid into the esophagus. If you have a hiatal hernia, a condition in which your stomach slides into your
chest via a too large opening in your diaphragm, it is repaired at the time of the fundoplication by closing the hole in your
diaphragm.
The surgery can be performed either open or laparoscopically (discussed below).
If performed open, you will have an incision made from the base of your breast bone to just above your belly button. The liver
is raised to expose the area where the esophagus meets the stomach. A space behind the esophagus is made to accommodate the
eventual wrap. Then the fundus of the stomach is freed from its attachments to the spleen. Finally, the fundus of the stomach
is wrapped around the esophagus and secured in place.
If the procedure is performed laparoscopically,
the larger incision is replaced by four or five half-inch to inch long incisions. The first incision is made by the belly
button. This is where the camera trocar (a long tube-like instrument) is placed. Then, an additional three or four incisions
are made to accommodate the other instruments.
95% of the time the surgery can be performed
via a laparoscopic procedure. A larger incision is made if a lot of scar tissue from previous surgery is encountered or if there is significant bleeding that needs to be controlled quickly.
