Gastrectomies are performed to treat stomach cancer and stomach wall perforations.
In severe cases of duodenal ulcers, the lower region of the stomach called the pylorus and the upper piece of the small intestine called the duodenum may need to be removed. If enough of the upper duodenum remains, a Billroth I surgery is done, in which the remaining piece of the stomach is reattached to the duodenum before the bile duct and pancreatic duct.
If the stomach cannot be reattached to the duodenum, a Billroth II procedure is done in which the remaining piece of the duodenum is sealed up, a hole is made into the next region of the small intestine known as the jejunum, and the stomach is reattached via this hole. Because the pylorus is responsible for grinding food and gently releasing it into the small intestine, removing it might cause food to go into the small intestine quicker than usual, resulting in gastric dumping syndrome.