A variety of pancreatic pathologies, malignant and benign, may indicate the need to remove the pancreatic tissue to the left of the superior mesenteric artery and vein (ie, distal pancreas). Distal pancreatectomy, which removes the body and tail of the pancreas, accounts for approximately 25 percent of all pancreatic resections. Distal pancreatectomy was first performed by Billroth in 1884. Less extensive resections can also be performed in the form of central pancreatectomy, which removes part of the body of the pancreas, or enucleation, which limits the resection to the lesion and immediately adjacent parenchyma.
The indications, preoperative evaluation and preparation, and techniques for resecting lesions of the body and the tail of the pancreas will be reviewed here. Resection of the head of the pancreas requires concomitant resection of the duodenum (ie, pancreaticoduodenectomy) and is discussed in detail elsewhere. (See "Pylorus-preserving pancreaticoduodenectomy".)
The pancreas is a compound exocrine and endocrine gland located in the retroperitoneum at the level of the second lumbar vertebrae. Exocrine pancreatic secretion is composed of enzymes, water, electrolytes and bicarbonate, which are delivered to the duodenum via the pancreatic duct of Wirsung and aid with digestion. Endocrine secretions include insulin, glucagon, and somatostatin from the islets of Langerhans, A cells, and D cells, respectively. Removal of up to 90 percent of the mass of the pancreas can be performed without resulting in diabetes.
The pancreas is divided into five parts including the head, uncinate process, neck, body, and tail (figure 1). The head of the pancreas lies to the right of the superior mesenteric artery. The uncinate process is a variable posterolateral extension of the head that passes behind the retropancreatic vessels and anterior to the inferior vena cava and aorta. The neck is defined as the portion of the gland overlying the superior mesenteric vessels. The body and tail lie to the left of the mesenteric vessels; there is no meaningful anatomic division between the body and tail.
Ductal anatomy — The pancreatic duct, located at the posterior (dorsal) aspect of the gland, joins the common bile duct to drain into the duodenum via the major papilla (ampulla of Vater) (figure 2 and picture 1). The anatomy of these ducts can vary. In 85 percent of individuals, the pancreatic duct and the common bile duct enter the duodenum through a common channel. In 5 percent of patients, both ducts enter the duodenum through the same ampulla but via separate channels. In the remaining 10 percent of patients, each duct enters the duodenum through a separate ampulla . The entry of the common bile duct into the pancreatic tissue posteriorly can also vary (figure 3).