Roux-en-YThe operation creates a very small upper stomach pouch (less than one ounce) by transecting (dividing) the stomach.
Ingested food passes out of the upper pouch through a small opening into the small intestine. Most of the stomach and the first part of the small intestine are bypassed by the food. Thus, the operation is termed a "gastric bypass with Roux-en-Y gastrojejunostomy." 
The major objective is to exclude most of the stomach. The point where the bile and pancreatic secretions are returned to mix with the ingested food is placed several feet downstream from the stomach. The gallbladder may be removed during the operation if it is found to be diseased.
The operation is usually done with laparoscopic instruments through several small incisions. The laparoscopic (minimally invasive) technique involves inserting a video telescope into the abdomen through a 12 mm incision. Five additional incisions (one 12 mm and four 5 mm) are placed in the upper abdomen. The operation is then carried out using specialized instruments. The laparoscopic approach has the potential advantages of smaller incisions, less pain, quicker recovery, fewer wound complications, earlier discharge from the hospital and less scarring while potentially providing the same weight reduction as the traditional open approach.
Occasionally, this surgery requires an incision from the breastbone to just above the umbilicus (belly-button) in order to gain access to the internal organs. If the operation cannot be safely completed using the small incisions, the abdomen will be opened and the operation will be completed. Not every patient is a candidate for the laparoscopic procedure. The surgeon will determine this during your initial visit.