- Gastric Bypass Procedure Details



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Gastric Bypass Procedure Details

The objective of Gastric Bypass, Roux en-Y surgery is to make a very small pouch out of the upper stomach, to restrict the amount of food which can be eaten.  That pouch is separated from the rest of the stomach, which is bypassed, by creating a new pathway into the intestines.  This pathway is called a “Roux en-Y” (named after the French surgeon, Dr. Roux, who first described this reconstruction in the 1800's).  The bowel is cut, and reconstructed in a Y configuration, so that two parts of the GI tract can feed into one.

Whether the operation is done through an incision, or laparoscopically, the basic methods, anatomy, and the results are the same, although the instruments differ.  Here’s how the operation is done laparoscopically:

Operating Ports:

Laparoscopy is done through “ports”, which are tubes that we pass instruments through, to operate on the internal organs.  We place several of these in the abdominal wall, through tiny incisions. (Learn more about how laparoscopy is done here.)

Measuring the Stomach Pouch:

stomach pouch measurmentThe upper stomach pouch should be very small, so that it will hold about one tablespoon of liquid.  To do this, a tube is passed through the back of the mouth into the stomach (while you’re asleep), and a balloon on the end of the tube is blown up to a volume of 15 milliliters (one tablespoon).  That serves as a measure, as we cut the stomach into upper and lower parts.

(All Drawings courtesy of Ethicon Endosurgery, Inc.)

Cutting the Stomach:

cutting staplingWith the balloon tube serving as a guide, a special stapler is placed across the stomach, which makes several rows of staples on each side, and cuts between them.  Additional cuts with the stapler made , until the stomach is completely divided.  The small upper pouch will be the new stomach.  The large lower part of the stomach will no longer contain any food.  It still has all its blood vessels, and makes normal secretions, and these can exit through its bottom connection, the pylorus, which is undisturbed.

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Constructing the Roux Limb:

creating the Roux limbcut small intestineThe small intestine is cut a few inches below the stomach, and a length of it is measured, to be used as the “Roux limb”, which will attach to the new little stomach.  The bowel is connected side-to-side, to form the ‘Y’.  The upper end of the Roux limb is passed behind the large intestine and the bypassed stomach, because that is the most direct and shortest route to the little upper stomach pouch.

Inserting the Stapler Anvil:

staple anvilThe stomach pouch is so small, that suturing a connection would be very difficult, especially by laparoscopy.  The “anvil” is a special stapler tool that makes this task easier. It is inserted by passing it through the throat into the stomach pouch, pulling it down into the pouch with a length of fine wire.  When the anvil is in place, the stem is brought through the side of the pouch, to connect it to the body of the stapler.

Inserting the Stapler and Connecting:

connecting stapler and anvilWith the anvil in place, the body of the stapler is inserted into the abdomen, through one of the small port sites, and then slid inside the bowel, to make the connection.  The stapler and anvil are snapped together, and the stapler is screwed shut, then fired, creating two circles of staples, with a hole through their middle, like a donut, and uniting the stomach pouch to the upper end of the Roux limb.

closing end of bowel
After the circular stapler is removed, the opened end of the bowel is re-closed with another application of the linear stapler.  This completes the construction of the connection between the stomach and small bowel.  The main part of the operation is now over.


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anatomy after gastric bypass surgeryThe final result looks like this.  Note that food enters the tiny stomach pouch, and exits through a small hole into the small intestine, which has been moved up, behind the lower stomach and large intestine, to be connected.  The lower, larger stomach pouch no longer receives any food, but still has a blood supply and is able to secrete digestive juices, which can leave by the same route as they always have, through the connection at the lower end (the "pylorus"), to pass down the duodenum, to the Y-connection just a few inches downstream.  All the food and digestive juices still travel through about 25 feet of small intestine, where absorption is essentially complete.  However, the small size of the stomach pouch makes one feel full quickly, while the food entering the upper small intestine causes a sense of satisfaction and indifference to further eating - the "Who Cares?" feeling.

Testing and Tidying Up:

Once all the connections are made, we test the upper one by inflating the stomach pouch with air from above, and looking for air bubbles while the connection is submerged under rinse water in the abdomen.  The abdomen is rinsed out and tidied up, a small drain tube is put in place, the ports are removed, and the operation is over.

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