CHAPTER 14 Pancreatic Resection
Case Study
A 65-year-old male is referred to a surgeon for evaluation of a pancreatic mass. He reports a 2-month history of progressive jaundice, anorexia, and loss of 15 pounds. Additionally, he notes intermittent dull upper abdominal pain, light-colored stools, and tea-colored urine. He was recently seen by a gastroenterologist and underwent endoscopic retrograde cholangiopancreatography (ERCP), which showed narrowing of the distal common bile duct and pancreatic duct; a biliary stent was placed during the procedure. A subsequent computed tomography (CT) scan of the abdomen and pelvis showed a mass in the head of the pancreas without evidence of metastases or vascular encasement or invasion (Fig. 14-1).
INDICATIONS FOR PANCREATIC RESECTION
I. Pancreatic Adenocarcinoma: Surgical resection remains the only potentially curative therapy for adenocarcinoma of the pancreas. Pancreaticoduodenectomy is indicated for tumors of the pancreatic head, whereas body and tail lesions are treated with distal pancreatectomy and splenectomy. Because of the aggressive nature of most pancreatic tumors, most are diagnosed at an advanced stage and only 20% of lesions are resectable at the time of diagnosis. Locally advanced cancers are deemed unresectable if they extend beyond the pancreatic parenchyma and invade or encase adjacent vascular structures (e.g., the mesenteric vessels or portal vein). Patients with locally advanced tumors may be candidates for neoadjuvant therapy consisting of chemotherapy and radiation. Resection in this patient population is sometimes possible after treatment if tumor characteristics are favorable on repeat imaging studies. Patients with metastatic disease receive no survival benefit from pancreaticoduodenectomy, but may be offered palliative therapies. Nonsurgical palliative interventions include biliary stenting, chemotherapy, radiation, and chemical neurolysis of the celiac plexus. Surgical palliation, including Roux-en-Y hepaticojejunostomy or choledocojejunostomy to relieve biliary obstruction and gastrojejunostomy to relieve duodenal obstruction, are often performed simultaneously (i.e., double bypass) when metastatic disease is discovered at the time of surgical exploration. In patients with pancreatic cancer, the median survival time after resection with curative intent is 16 to 24 months. Patients with metastatic disease fare much worse, with a median survival of less than 6 months.
II. Pancreatic Cystic Neoplasms: Cystic neoplasms of the pancreas include serous cystic neoplasms, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms (IPMNs). Combined, these represent fewer than 10% of all pancreatic neoplasms. Distinguishing cystic neoplasms from inflammatory pseudocysts, which are much more common, often poses a considerable diagnostic challenge. Smaller mucinous cystic neoplasms (<3 cm) with favorable imaging criteria and serous cystic neoplasms, which are almost always benign, may be monitored with serial imaging. In contrast, IPMNs are more likely to harbor invasive carcinoma and should generally be resected.
III. Pancreatic Neuroendocrine Tumors: Neuroendocrine tumors of the pancreas are a rare and heterogeneous group of lesions that includes insulinomas, glucagonomas, gastrinomas, somatostatinomas, and VIPomas. These tumors can arise sporadically or as a part of the multiple endocrine neoplasia (MEN) I syndrome. Symptoms result from overproduction of biologically active hormones. Gastrinomas are associated with the Zollinger-Ellison syndrome, which is characterized by gastric acid hypersecretion and intractable peptic ulcer disease. Gastrinomas and somatostatinomas are frequently malignant and should be resected with appropriate margins. Insulinomas are most often benign and can be enucleated. Insulinomas and glucagonomas are most often found in the body and tail of the pancreas. In contrast, somatostatinomas and gastrinomas are more often found in the pancreatic head.
IV. Ampulla of Vater Neoplasms: Ampullary adenomas may be sporadic or associated with familial cancer syndromes, such as familial adenomatous polyposis (FAP). These adenomas are associated with a risk of malignant degeneration and are therefore treated with resection.
V. Periampullary Duodenal Neoplasms: Like ampullary adenomas, duodenal adenomas may be sporadic or may be associated with familial cancer syndromes, such as FAP or Peutz-Jeghers syndrome. Duodenal adenomas can progress to adenocarcinoma and should be removed when discovered. Inability to achieve complete excision, either endoscopically or via a transduodenal surgical approach, is an indication for pancreaticoduodenectomy. Duodenal adenocarcinoma is likewise treated with pancreaticoduodenectomy.
VI. Distal Common Bile Duct Strictures: Obstructive jaundice may result from benign or malignant biliary strictures. The most common cause of a benign stricture is iatrogenic injury (e.g., during cholecystectomy). Other causes include recurrent or chronic pancreatitis and choledocholithiasis. Malignant etiologies include primary bile duct cancers (cholangiocarcinoma) and pancreatic neoplasms. Pancreaticoduodenectomy is indicated if a malignant stricture is diagnosed or suspected.
VII. Sequelae of Chronic Pancreatitis: Inflammation of the pancreas can lead to scarring and stenosis of the pancreatic duct and common bile duct. Inflammatory masses in the setting of chronic pancreatitis and ductal strictures are often difficult to distinguish from pancreatic neoplasia. If the diagnosis of neoplasia cannot be excluded, such masses should be resected. Pancreatic resections may also be indicated for the management of intractable pain in the setting of chronic pancreatitis, although other operative procedures may be preferable.
VIII. Trauma: Injury to the pancreas may result from blunt or penetrating trauma. The management of pancreatic trauma is largely dependent on the severity and location of injury. Penetrating injuries to the head of the pancreas are typically associated with concomitant injuries to surrounding structures, including the duodenum, bile duct, or liver. Severe devitalizing injuries to the pancreatic head, duodenum, and distal common bile duct may require pancreaticoduodenectomy. The mortality rate associated with a Whipple procedure performed in this setting approaches 60%. Injuries localized to the body and tail are best treated with a distal resection, with or without splenectomy.
PREOPERATIVE EVALUATION
I. History and Physical Examination: In the patient with a pancreatic mass, a history of abdominal pain, back pain, loss of appetite, vomiting, weight loss, and jaundice, should be elicited. Back pain may indicate invasion of a tumor into the retroperitoneum. Vomiting suggests a gastric outlet obstruction. In the presence of metastatic disease, physical examination may reveal an umbilical nodule (Sister Mary Joseph’s node) or left supraclavicular lymphadenopathy (Virchow’s node). Digital rectal examination may reveal peritoneal implants in the pelvis (Blumer’s shelf).
II. Computed Tomography and Magnetic Resonance Imaging: An enhanced CT scan of the abdomen and pelvis with fine cuts through the pancreas is useful for localizing a mass, delineating its relationship to the superior mesenteric vessels and portal vein, and detecting metastatic disease. Magnetic resonance imaging may be helpful if CT scan findings are equivocal and is of particular utility in the evaluation of suspected liver metastases.
III. Endoscopy: Esophagogastroduodenoscopy and ERCP allow for the evaluation of the stomach, duodenum, common bile duct, and pancreatic duct. Biliary stenting can be performed in conjunction with ERCP for the treatment of obstructive jaundice. Endoscopic ultrasound and ultrasound-guided fine-needle aspiration (FNA) may be used to evaluate the pancreas and peripancreatic lymph nodes for the presence of disease, to determine the relationship of a tumor to adjacent vascular structures, and to obtain a tissue diagnosis. Although preoperative FNA of pancreatic masses is commonly performed, preoperative tissue diagnosis is not essential before proceeding with a pancreatic resection if pancreatic cancer is strongly suspected.
IV. Laboratory Testing: Preoperative laboratory testing should include a complete blood count and electrolyte panel, including blood urea nitrogen and creatinine levels. Serum albumin, liver-associated enzyme, bilirubin, prothrombin time, and partial thromboplastin time should be measured because many patients with pancreatic disease are malnourished and have impaired liver synthetic function and some degree of biliary obstruction. The level of CA 19-9, a serum tumor marker, is often elevated in patients with pancreatic cancer and should be measured preoperatively. In cases of suspected pancreatic endocrine neoplasia, laboratory confirmation of hormone hypersecretion should be sought. A type and screen with crossmatch should be obtained for all patients before pancreatic resection.
V. Diagnostic Laparoscopy: In some series, up to 30% of patients with pancreatic carcinoma that is determined to be resectable by preoperative imaging are found to have metastatic disease to the liver or peritoneal surfaces at the time of exploration. Laparoscopy can be used to explore the abdomen before commiting to an unnecessary laparotomy (Fig. 14-2). Some surgeons use laparoscopic ultrasonography to allow for a more sensitive examination of the liver. The indications for diagnostic laparoscopy in pancreatic cancer are evolving.
COMPONENTS OF PANCREATIC RESECTION AND APPLIED ANATOMY
Figure 14-3 Arterial supply (top) and venous drainage (bottom) of the pancreas and duodenum.
(From Skandalakis JE, Gray SW, Rowe JS Jr, et al: Anatomical complications of pancreatic surgery. Contemp Surg 15:17–50, 1979. Reprinted with permission.)
Preoperative Considerations
I. Preoperative antibiotics covering bowel and biliary flora are administered within 1 hour before skin incision.
Whipple Procedure
I. Incision and Exploration
A. Pancreaticoduodenectomy may be performed through either a vertical midline or a bilateral subcostal incision.
B. On entering the peritoneal cavity, a thorough exploration of all peritoneal surfaces, the liver, and omentum is undertaken. Suspicious lesions are identified, and biopsy specimens are obtained and sent for frozen section examination. If metastases are discovered, the planned resection is aborted and a palliative bypass procedure may be performed.
II. Right Colon Mobilization and Kocher Maneuver
A. The right colon and hepatic flexure are mobilized by dividing the peritoneal attachments along the white line of Toldt, exposing the duodenum.
III. Cholecystectomy and Periportal Dissection
A. The gallbladder is dissected off the liver bed with electrocautery, beginning at the fundus and continuing toward the neck. The cystic artery and duct are ligated and divided separately.
B. After removal of the gallbladder, dissection of the porta hepatis is performed and the portal vein, hepatic artery, and common bile duct and common hepatic duct are identified. The common hepatic duct is dissected free from adjacent vascular structures and transected above the cystic duct stump. Regional lymph nodes are dissected down toward the resection specimen.
C. The gastroduodenal artery (GDA) is identified as it arises from the common hepatic artery and is divided. The remaining stump is doubly ligated to minimize the risk of rebleeding. Division of the GDA allows for clear exposure of the portal vein as dissection continues behind the pancreatic neck.
D. The dissection is continued inferiorly along the avascular plane between the anterior surface of the portal vein and the neck of the pancreas.
E. The plane behind the pancreatic neck is then developed from an inferior approach. The gastrocolic omentum is divided between clamps to allow for access to the lesser sac. The stomach is retracted superiorly and the transverse colon is retracted inferiorly to expose the pancreas. The SMA and SMV are identified by following the middle colic vessels down to their origin. The pancreas is then dissected off the anterior surface of the SMV until the pancreatic neck is free.
IV. Division of the Pancreas, Duodenum, and Proximal Jejunum (Removal of the Specimen)
B. The pancreatic neck is sharply divided. Bleeding from the distal cut edge of the pancreas confirms adequate perfusion to support healing of the pancreaticojejunostomy. If the cut edge does not bleed, the distal pancreas may be cut back further.
C. The uncinate process is dissected away from the SMA and SMV. Vascular branches in this region are divided between ties.
D. The small bowel is divided with a stapler at a point approximately 10 to 20 cm distal to the ligament of Treitz. The mesenteric branches supplying the isolated segment of jejunum and distal duodenum are divided. The ligament of Treitz is fully mobilized, and the distal duodenum and jejunum are passed beneath the SMA and SMV. As the specimen is reflected back toward the patient’s right, any remaining duodenal attachments or vascular branches between the superior mesenteric vessels and the pancreas are divided.
V. Reconstruction (Pancreaticojejunostomy, Hepaticojejunostomy, and Duodenojejunostomy) (Fig. 14-5)
A. An opening is created in the transverse mesocolon to the right of the middle colic vessels through which the distal end of the divided jejunum is delivered. A pancreatic duct–to–small bowel mucosa anastomosis is performed in an end-to-side fashion (i.e., end of pancreatic duct to side of jejunum). If the pancreatic duct is small, the anastomosis can be performed over a stent (typically, a small-caliber feeding tube) to maintain the patency of the duct during healing. Reinforcing sutures are placed between the pancreatic capsule and the seromuscular layer of the jejunum.
C. A mobile segment of the jejunum distal to the hepaticojejunostomy is brought up to the duodenum in an antecolic fashion (in front of and over the top of the transverse colon). The duodenal staple line is opened, and an end-to-side anastomosis (end of duodenum to side of jejunum) is performed. After completion of the duodenojejunostomy, the nasogastric tube can be advanced past the anastomosis.
Distal Pancreatectomy
I. Incision and Exploration
A. Distal pancreatectomy may be performed through either a vertical midline or a left subcostal incision.
B. On entering the peritoneal cavity, a thorough exploration of all peritoneal surfaces, the liver, and the omentum is undertaken. If suspicious lesions are found, biopsy specimens are obtained and sent for frozen section examination. If metastases are discovered at this point, the planned resection is aborted.
II. Exposure and Mobilization of the Spleen and Pancreatic Body and Tail
A. The lesser sac is entered by dividing the gastrocolic omentum. The stomach is retracted superiorly and the colon is retracted inferiorly to allow for exposure of the pancreatic body and tail.
Additional Operative Considerations
I. Drains: A nasogastric tube is maintained after both pancreaticoduodenectomy and distal pancreatectomy. Placement of closed-suction drains posterior to the hepaticojejunostomy and the pancreaticojejunostomy at the conclusion of pancreaticoduodenectomy sometimes facilitates postoperative management and is advocated by some surgeons. A drain may be placed adjacent to the pancreatic staple line after distal pancreatectomy.
II. Gastrostomy and Feeding Tubes: Gastrostomy tubes and feeding jejunostomy tubes are sometimes placed after pancreaticoduodenectomy. Gastrostomy tubes are particularly helpful in cases of postoperative delayed gastric emptying; however, it is difficult to reliably predict which patients will encounter this complication.
III. Laparoscopy: Laparoscopic distal pancreatectomy is performed routinely at some centers. Although the positioning and approach are somewhat different than with the open procedure, the basic concepts of exposure and resection are similar. Laparoscopic pancreaticoduodenectomy has been reported in the literature, but is infrequently performed.
COMPLICATIONS
I. Bleeding after pancreatic resection is relatively common because patients with pancreatic neoplasms may be malnourished and have impaired liver synthetic function. Coagulopathy should be aggressively corrected in the postoperative period. Rarely, re-exploration for surgical bleeding is necessary.
II. Pancreatic leak (pancreatic fistula) is the most common complication of pancreatic resection. Such leaks are often heralded by high-volume, amylase-rich output from the surgical drain. After a Whipple procedure, many surgeons routinely measure amylase levels in the drainage fluid several days after surgery or after patients resume a regular diet, regardless of the rate of drainage. CT scanning is sometimes useful in identifying undrained intra-abdominal fluid collections, which generally mandate percutaneous drainage. Low-output leaks can typically be managed with maintenance of drainage alone. High-output leaks require a more aggressive approach, including bowel rest and total parenteral nutrition.
III. Bile leaks after pancreaticoduodenectomy are rare. When they do occur, they are most often managed with closed-suction drainage. Persistent leaks may require percutaneous transhepatic drainage to divert bile flow from the hepaticojejunostomy.
IV. Delayed gastric emptying is one of the most common complications after a Whipple procedure, occurring in 20% to 70% of patients. The etiology of delayed gastric emptying is poorly understood, and in most cases, symptoms improve with time. An upper gastrointestinal study should be obtained to rule out a mechanical obstruction if delayed gastric emptying continues beyond the first postoperative week. Promotility agents, such as metoclopramide and erythromycin, are sometimes helpful.
Brugge WR, Lauwers GY, Sahani D, et al. Cystic neoplasms of the pancreas. N Engl J Med. 2004;351:1218-1226.
Steer ML. Exocrine pancreas. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, editors. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 17th ed. Philadelphia: Saunders; 2004:1667-1674.
Thayer SP, Warshaw AL. Periampullary cancer. In: Cameron JL, editor. Current Surgical Therapy. 8th ed. Philadelphia: Elsevier Mosby; 2004:494-504.
