Some procedures are performed through conventionally large (open) abdominal incisions. However, most are done laparoscopically, involving multiple small abdominal incisions through which instruments are inserted.
The stomach is first divided into a smaller upper section (pouch) approximately the size of an egg. Most of the stomach is bypassed, and food is no longer stored or digested.
To allow food to pass, the small intestine is divided and connected to the new stomach pouch. The small bowel segment which empties the bypassed or larger stomach is connected to the small bowel about 3-4 feet downstream, resulting in a bowel connection that resembles the letter Y.
The surgery usually takes a few hours. You awaken in a recovery room post-surgery, where medical staff monitors for any complications.