jejunum or stomach. During the surgery a cholecystectomy is performed to remove the gallbladder. This portion is not done en bloc, as the gallbladder is removed separately. Relevant nearby anatomy not removed during the procedure include the major vascular structures in the area: the portal vein, the superior mesenteric vein, and the superior mesenteric artery, the inferior vena cava. These structures are important to consider in this operation especially if done for resection of a tumor located in the head of the pancreas. If the tumor encases (wraps around 50% or more of the vessel) the celiac artery, superior mesenteric artery, or inferior vena cava it is considered unresectable due to the lack of patient benefit from the operation while having very high risk. Occasionally a portion of the superior mesenteric vein or portal vein is attached or inseparable from the tumor. In this setting vascular surgeons resect the involved portion of the vessel, and the vessel is repaired either via end-to-end anastomosis, repair of the side wall of the vein, or a vein graft. Medical indications Pancreaticoduodenectomy is most often performed as curative treatment for periampullary cancer, which include cancer of the bile duct, duodenum, ampulla or head of the pancreas. The shared blood supply of the pancreas, duodenum and common bile duct, necessitates en bloc resection of these multiple structures. Other indications for pancreaticoduodenectomy include chronic pancreatitis, benign tumors of the pancreas, cancer metastatic to the pancreas, multiple endocrine neoplasia type 1 and gastrointestinal stromal tumors. Pancreatic cancer Pancreaticoduodenectomy is the only potentially curative intervention for malignant tumors of the pancreas. However, the majority of patients with pancreatic cancer present with metastatic or locally advanced un-resectable disease; thus only 15-20% of patients are candidates for the Whipple procedure. Surgery may follow neoadjuvant chemotherapy, which aims to shrink the tumor and increasing the likelihood of complete resection. Post-operative death and complications associated with pancreaticoduodenectomy have become less common, with rates of post-operative mortality falling from 10 to 30% in the 1980s to less than 5% in the 2000s. Ampullary Cancer Ampullary cancer arises from the lining of the ampulla of Vater. Duodenal Cancer Duodenal cancer arises from the lining of the duodenal mucosa. Majority of duodenal cancers originate in the second part of the duodenum, where ampulla is located. Cholangiocarcinoma Cholangiocarcinoma, or cancer of the bile duct, is an indication for the Whipple procedure when the cancer is present