A pancreaticoduodenectomy, also known as a Whipple procedure, is a major surgical operation most often performed to remove cancerous tumours from the head of the pancreas. It is also used for the treatment of pancreatic or duodenal trauma, or chronic pancreatitis. Due to the shared blood supply of organs in the proximal gastrointestinal system, surgical removal of the head of the pancreas also necessitates removal of the duodenum, proximal jejunum, gallbladder, and, occasionally, part of the stomach. Anatomy involved in the procedure The most common technique of a pancreaticoduodenectomy consists of the en bloc removal of the distal segment (antrum) of the stomach, the first and second portions of the duodenum, the head of the pancreas, the common bile duct, and the gallbladder. Lymph nodes in the area are often removed during the operation as well (lymphadenectomy). However, not all lymph nodes are removed in the most common type of pancreaticoduodenectomy because studies showed that patients did not benefit from the more extensive surgery. At the very beginning of the procedure, after the surgeons have gained access to the abdomen, the surfaces of the peritoneum and the liver are inspected for disease that has metastasized. This is an important first step as the presence of active metastatic disease is a contraindication to performing the operation. The vascular supply of the pancreas is from the celiac artery via the superior pancreaticoduodenal artery and the superior mesenteric artery from the inferior pancreaticoduodenal artery. There are additional smaller branches given off by the right gastric artery which is also derived from the celiac artery. The reason for the removal of the duodenum along with the head of the pancreas is that they share the same arterial blood supply (the superior pancreaticoduodenal artery and inferior pancreaticoduodenal artery). These arteries run through the head of the pancreas, so that both organs must be removed if the single blood supply is severed. If only the head of the pancreas were removed it would compromise blood flow to the duodenum, resulting in tissue necrosis. While blood supply to the liver is left intact, the common bile duct is removed. This means that while the liver remains with a good blood supply the surgeon must make a new connection to drain bile produced in the liver. This is done at the end of the surgery. The surgeon will make a new attachment between the pancreatic duct and the