Use an upper midline or extended left subcostal incision, depending on the body habitus of the patient. Make a window in the gastrocolic omentum by serially clamping and dividing the gastroepiploic vessels on the greater curvature of the stomach. Divide these from the region of the distal antrum to the short gastric vessels. Retract the portion of the stomach that is cephalad to the greater omentum inferiorly. Place retractors or stay sutures to maintain the stomach in an elevated position. Divide the avascular folds between the stomach and pancreas (gastropancreatic folds, or Allen’s veil) to expose the body and tail of the pancreas fully. The splenic vessels may be palpable in the region of the distal pancreas. The splenic artery runs along the superior surface of the pancreas and is often visible, palpable, or both. The splenic vein lies posterior to the pancreas and cannot be seen until the pancreas is mobilized. Incise the peritoneum along the inferior border of the pancreas with electrocautery.

Elevate the pancreas out of the retroperitoneum by blunt dissection in an avascular (normally) plane. The splenic artery and vein will be elevated along with the body and tail of the pancreas. Identify the point at which the pancreas is to be divided. Generally, this point will be somewhat to the left of the superior mesenteric vein. Develop a plane between the pancreas and the splenic artery and splenic vein by careful blunt dissection. Use Silastic vessel loops on the two vessels to facilitate traction after the plane has been developed. Divide the pancreas using a TA-55 stapler with
3.5-mm staples. Place Allis clamps on the distal pancreas and lift up.

Multiple, short, fine vessels connecting the body and tail of the pancreas to the splenic artery and splenic vein must then be isolated and serially clipped or ligated. If these small vessels are inadvertently avulsed, use fine Prolene sutures to obtain hemostasis in the splenic artery and splenic vein. Continue the dissection out to the tail of the pancreas, preserving the splenic artery and splenic vein. Check the area for hemostasis and place omentum over the pancreatic stump. Closed-suction drains may be placed in the bed of the resection if desired.

The greater omentum is attached to the greater curvature of the stomach and first part of the duodenum. On the left, it is continuous with the gastrosplenic ligament. The entire length of its posterior surface is adherent to the entire length of the transverse colon. That portion of the greater omentum connecting the stomach and transverse colon is the gastrocolic omentum (ligament). The gastroepiploic vessels, contained within the greater omentum, typically are close to the stomach, but may be 2 cm or more distant from the stomach.

On the left, the gastrosplenic and splenocolic ligaments are continuous with the greater omentum. Multiple, short, gastric arteries (commonly, four to six) arise from the splenic artery or its branches and run through the gastrosplenic ligament to the greater curvature of the stomach at the fundus. The left gastroepiploic artery has a similar origin and similar course, except that it parallels the greater curvature, running from left to right, ultimately anastomosing with the right gastroepiploic artery. There are no vessels of consequence in the splenocolic ligament, although small communications may exist between the splenic vessels and branches of the middle or right colic vessels.

The lienorenal ligament attaches the spleen to the retroperitoneum. In this ligament are the major splenic vessels and the
tail of the pancreas, which usually is either in contact with the splenic hilum or is no more than 1 cm distant from the hilum.

The gastropancreatic folds are formed by the left gastric artery as it passes from the celiac trunk to the upper part of the lesser curvature. Avascular, filmy connections can occur between the visceral peritoneum of the stomach and the parietal peritoneum covering the pancreas. These are common at the right extremity of the stomach, where the antrum is in close proximity to the head of the pancreas, and, on the left, where the posterior surface of the stomach is very close to the tail of the pancreas. These avascular folds tether the stomach to the posterior wall of the lesser sac, as the duodenum starts to become retroperitoneal, and to the gastrosplenic ligament and its contained vasculature.

The splenic artery runs along the superior border of the pancreas from its celiac trunk origin to the hilum of the spleen. The celiac trunk lies superior and to the left of the neck of the pancreas. As it progresses toward the spleen, it has a characteristically tortuous course (in the adult) owing to tethering by pancreatic branches, and it frequently dips downward posterior to the pancreas. By contrast, the splenic vein should not be visible until the pancreatic tail and splenic hilum are explored because this vein is posterior to the pancreas. As these vessels approach the splenic hilum, both artery and vein have a variable number of splenic branches or tributaries (usually two or three) that serve the different splenic segments; this branching most commonly occurs about 4 cm from the splenic hilum, but the distance may range from 1 to 12 cm. Typically, the splenic vein tributaries are inferior and somewhat posterior to the corresponding arterial branches.

Posterior to the pancreas, an avascular plane exists as a result of the fusion of the mesogastrium with the posterior parietal peritoneum and that those more proximal structures contained within the mesogastrium become retroperitoneal. As could be expected, the avascular fusion plane is also posterior to the splenic vessels.

The relationship of the major vessels posterior to the pancreas is also important. The portal vein, formed by the union of the superior mesenteric and splenic veins, lies to the right of the aorta and superior mesenteric artery. The splenic vein, which lies more or less in the transverse plane, joins the superior mesenteric vein by passing between the superior mesenteric artery and pancreas; thus, in this region, the splenic vein is the most anterior major vascular structure.

As the splenic artery and vein travel along the length of the pancreas, several short, delicate radicles either supply or drain the pancreas. There are more pancreatic veins (15 to 31) than there are pancreatic arteries (4 to 11), and both appear to be distributed fairly evenly along the length of the vessels.