Anatomy - Pylorus-preserving duodenohemipancreatectomy according to Traverso-Longmire with T-drainage (pp-Whipple)

The pancreas, composed of lobules, has a reddish-gray color, is 14 – 18 cm long and weighs 65 – 80 grams. It lies at the level of the 1st and 2nd lumbar vertebrae and extends wedge-shaped from the epigastric region into the left hypochondriac region. Due to developmental history, the organ is in close neighborhood relationship to the upper abdominal organs and vessels.

The pancreas is enclosed by capsule-like connective or fatty tissue and is divided into three sections: head, body and tail. While in the posterior head area there is a somewhat firmer connective tissue plate, the gland is otherwise dorsally connected to the connective tissue mostly loosely. As a retroperitoneal organ, the gland is covered with peritoneum on its anterior surface.

The widest part of the gland is the caput pancreatis, which – located to the right of the spine – fits into the loop formed by the duodenum. Both the anterior and posterior surfaces of the duodenum can be overlaid by glandular tissue to varying degrees here. The head encompasses with its caudal portion (uncinate process) from behind the superior mesenteric vein, occasionally also the artery. The groove located in the uncinate process and in the rest of the pancreatic head portion is called the pancreatic incisure.

The pancreatic part located at the level of the 1st lumbar vertebral body represents with a width of about 2 cm the transition area from head and body and lies over the superior mesenteric vessels. From a surgical perspective, this section is also called the neck of the pancreas.

The elongated body of the pancreas runs obliquely upward over the 1st and 2nd lumbar vertebrae, bulges ventrally into the omental bursa and curves to the splenic hilum, with the transition to the tail occurring without exact anatomical demarcation. Dorsal to the body are, besides the spine, the aorta, the inferior vena cava as well as the superior mesenteric artery and vein.

The tail of the pancreas forms the pointed continuation of the gland body and extends to the splenorenal ligament or into it.

The pancreas can be arranged in various shape variants, obliquely running, S-shaped, transversely running and L-shaped. A horseshoe shape and an inverted V-shape have also been described. The transitions between the shape variants are fluid.

Topographically, the pancreas has the following relationships to neighboring organs as well as retroperitoneally located conducting pathways:

• ventrally the omental bursa and the posterior surface of the stomach
• to the right there is a close relationship between the head and the duodenal loop
• to the left there is a close relationship to the splenic hilum
• the posterior wall of the pancreas touches at the level of the head the portal vein, the superior mesenteric artery and vein as well as the common bile duct, at the level of the body the splenic artery and vein, the inferior mesenteric vein, the inferior vena cava as well as the abdominal aorta, at the level of the tail the left kidney

The approximately 2 mm thick pancreatic duct traverses the organ along its longitudinal extent near the posterior surface and receives numerous short glandular ducts along its path, which enter it perpendicularly. In about 77% of cases, the duct opens together with the common bile duct on the major duodenal papilla in the posterior wall area of the descending part of the duodenum; in the remaining cases, the openings of both ducts are close to each other. The accessory pancreatic duct, an accessory excretory duct, is often only rudimentary or completely absent. If present, it opens on the minor duodenal papilla.