Distal Pancreatectomy

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Chapter 15

Distal Pancreatectomy

Natalie E. Joseph

Introduction

Distal pancreatectomy is the term applied to resection of that portion of the pancreas extending to the left of the midline and not including the duodenum and distal bile duct. First described by Billroth in 1884, distal pancreatectomy is performed for various benign and malignant conditions involving the body and tail of the pancreas. These include inflammatory conditions such as chronic pancreatitis and symptomatic pseudocysts, pancreatic trauma, neuroendocrine tumors, pancreatic adenocarcinoma, solid neoplasms of indeterminate etiology, and cystic neoplasms of the pancreas. Because of the lower incidence of resectable malignant pancreatic neoplasms involving the body and tail of the pancreas, as well as the late appearance of clinical symptoms in this portion of the gland, distal pancreatectomy is performed less often than resection of the pancreatic head.

Preoperative Evaluation

The indication for distal pancreatectomy will dictate preoperative workup and also influence surgical decision making. Multidetector, dynamic, contrast-enhanced computed tomography (CT) is the preoperative imaging modality of choice for all indications and is essential to surgical planning. CT provides detailed images of the pancreatic pathology and its relationship to surrounding organs, major vasculature, and pancreatic ducts, as well as the presence of metastatic disease (Fig, 15-1). Other modalities, such as endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS), may also be helpful when a definitive mass is not well visualized.

FIGURE 15–1 Anatomy for preoperative evaluation of pancreas.

Surgical Approach

The standard approach to resection of the body and tail of the pancreas is through an upper midline incision from the xiphoid process to just below the umbilicus. Alternatively, a bilateral subcostal incision can be used. The surgical approach depends on the indication, with several different approaches available.

Open Retrograde Distal Pancreatectomy with Splenectomy

Retrograde distal pancreatectomy with splenectomy is the standard procedure for management of proven or suspected cancers in the body and tail of the pancreas, to ensure the adequacy of the lymph node dissection, or with tumors when the anatomic constraints dictate sacrificing the spleen (Fig. 15-2, A).

FIGURE 15–2 Open retrograde distal pancreatectomy with splenectomy.

The pancreas is approached by opening the lesser sac through the gastrocolic ligament below the gastroepiploic vessels (Fig. 15-2, B). The peritoneum overlying the inferior border of the pancreas is divided lateral to the superior mesenteric vessels toward the tail. The splenocolic and splenorenal attachments are divided to mobilize the spleen anteriorly and to the right, separating it from splenic flexure of the colon and from Gerota’s fascia (Fig. 15-2, C).

The short gastric vessels connecting the splenic hilum with the greater curvature of the stomach must be isolated and divided to facilitate mobilization of the tail of the pancreas. The dissection along the inferior margin of the pancreas is continued, and the inferior and posterior peritoneal attachments are divided. Care must be taken because there are numerous venous tributaries from the posterior aspect of the pancreas into the splenic vein. This dissection opens up the retroperitoneal window behind the pancreas.

Division of Splenic Artery and Vein

Understanding the vascular anatomy of the pancreas is essential to safe technique (Fig. 15-3, A). The splenic artery is identified at its origin from the celiac trunk and traced distally along the posterosuperior border of the pancreas. It is divided just distal to its origin. The splenic vein is then isolated and divided just proximal to its confluence with the portal vein, preserving the inferior mesenteric vein if possible (Fig. 15-3, B).

FIGURE 15–3 Division of splenic artery and vein and pancreas.

Division of Pancreas

The pancreas is rotated medially and the point of transection determined based on the location of the tumor. The pancreatic parenchyma may be divided using one of several techniques, including a gastrointestinal stapler or electrocautery. If well visualized, the pancreatic duct is oversewn (Fig. 15-3, C and D).

Radical Antegrade Modular Pancreaticosplenectomy

The goals of pancreatic resection for cancer should be to perform a complete resection with clear margins and resection of regional lymph nodes (Fig. 15-4). Radical antegrade modular pancreaticosplenectomy (RAMPS), described by Strasberg in 2003, is a modified technique of distal pancreatectomy developed to allow for en bloc resection of the pancreas with an N1 lymphadenectomy. With this approach, dissection proceeds from medial to lateral (right to left), removing all nodal tissue surrounding the body and tail of the pancreas.

FIGURE 15–4 Lymphatic drainage of pancreas.

Division of Neck of Pancreas

The lesser sac is entered as previously described and the dissection carried to the origin of the right gastroepiploic artery. From the inferior border of the pancreas, the pancreatic neck is dissected off the superior mesenteric vein and the portal vein. The middle colic vein may be ligated to facilitate exposure. The hepatic artery is identified at the superior border of the pancreas and traced to identify the lymph nodes on the hepatic artery and portal vein. The gastroduodenal artery is ligated to expose the anterior surface of the portal vein, which is then dissected away from the neck of the pancreas; the neck is transected as previously described. The splenic artery and vein are then ligated and divided at their origins. The dissection is then extended posteriorly to include the retroperitoneal tissue and lymphatic tissue anterior to the left renal vein and all lymphatics to the left of the superior mesenteric artery and inferior to the celiac artery. The spleen is mobilized by dividing the splenorenal and splenocolic attachments.

Distal Pancreatectomy with Splenic Preservation

Preservation of the spleen can be selectively applied in other benign conditions. Splenic preservation has the advantage of fewer infectious complications and no long-term risk of postsplenectomy sepsis. Distal pancreatectomy with splenic preservation can be performed using one of two techniques: (1) preserving the splenic artery and vein, by isolating and dividing the small branches between these vessels and the pancreas, or (2) ligating the splenic artery and vein with the pancreas, but preserving the collateral blood supply to the spleen provided by the short gastric and left gastroepiploic vessels, as described by Warshaw (see Suggested Readings).

If the spleen will be preserved, the surgical approach is similar to that for RAMPS. The lesser sac should be opened generously to allow for full exposure from the right gastroepiploic vessels medially, to the short gastric vessels laterally. The short gastric vessels are not divided when splenic preservation is planned. The lesser sac is opened, exposing the anterior aspect of the pancreas. The procedure can be carried out in a medial-to-lateral direction. An incision is made in the peritoneum along the inferior border of the body and tail of the pancreas, dissecting along the neck of the pancreas until the superior mesenteric vein and portal vein are exposed. The splenic vein is identified posteriorly.

An incision is then made along the superior edge of the pancreas to the left of the gastroduodenal artery. A plane is then developed between the portal vein and the neck of the pancreas by gentle blunt dissection. Once the opening is complete, a Penrose drain can be passed under the neck of the pancreas for anterior traction (Fig. 15-5). This facilitates mobilization of the splenic vein away from the proximal body of the pancreas. The small, fragile venous branches from the pancreatic parenchyma to the splenic vein should be divided. A distance of 2 to 3 cm is dissected laterally. The neck of the pancreas is divided, sparing the splenic vessels.

FIGURE 15–5 Mobilization of pancreas during spleen-preserving distal pancreatectomy.

Once the pancreas is divided, the body of the pancreas is retracted superiorly to visualize the splenic artery. Small branches of the splenic artery should be controlled at this juncture to minimize bleeding. The distal pancreas is elevated off the splenic artery and vein. The remaining superior and inferior peritoneal attachments are divided to the level of the splenic hilum. The proximal jejunum may be in close proximity at this point and should be reflected inferiorly.

The final attachments of the pancreas can then be divided. The posterior margin of the dissection will be the splenic vein and artery. In the presence of larger tumors, sparing the splenic vessels may be difficult because of distortion in the course of the vessels.

Laparoscopic Distal Pancreatectomy

The last decade has seen increasing use of the laparoscopic approach to distal pancreatectomy, particularly in the management of cystic and benign lesions. The patient may be placed supine or in a modified lithotomy position with the left side elevated. If a laparoscopic resection will be performed, particular attention is paid to port placement, but the surgical approach is the same.

Trocar Placement for Laparoscopic Approach

Five ports are placed (Fig. 15-6); a 10-mm supraumbilical port is placed just to the left of midline. After the abdomen is insufflated, a 10- to 12-mm port is placed in the left midclavicular line, a 5-mm port in the subxiphoid area, a 5-mm trocar in the left anterior axillary line, and a 5-mm port in the right midclavicular line.