GENERAL PRINCIPLES AND PREOPERATIVE APPROACHES

Although pancreatic cancer is the most common of periampullary tumors, cancers of the ampulla, the duodenum, and the distal bile duct have a better long-term survival after curative pancreaticoduodenectomy. Although rare, there also are cystic pancreatic tumors and endocrine tumors, for which surgical extirpation is indicated.

ANATOMIC CONSIDERATIONS (See Chapter 1)

It is essential that the surgeon be familiar with the arterial variations to avoid injury and particularly to avoid hepatic ischemia in the jaundiced patient. The important variations are those of the right hepatic artery. The right hepatic artery usually crosses in front of the portal vein, but in a small percentage of cases, it passes behind the portal vein, raising a suspicion of an accessory or replaced right hepatic artery. This arises from the superior mesenteric artery and passes on the right and somewhat posterior to the common bile duct (see Chapter 1, Fig. 1-27). The difference between a true right accessory or replaced hepatic artery and a right hepatic artery passing behind the portal vein usually can be determined by palpation just above the duodenum, where a true ectopic artery will be felt.

In most cases, the right hepatic artery passes behind the bile duct, but a right hepatic artery passing in front of the common bile duct is common (Chapter 1) and should be identified during mobilization of the gallbladder and cystic duct. Unresectability is not defined by variant anatomy but rather by the local invasion of major vascular structures independent of their position. Thus the presence of an accessory or replaced right hepatic artery from the superior mesenteric artery does not preclude resection of the pancreatic head. Often the vessel will pass posteriorly and can be carefully dissected free.

Lymphatic drainage from pancreatic head lesions results in a high incidence of lymph node positivity in the posterior pancreaticoduodenal region. This major drainage area should be resected, taking all the tissue in front of the vena cava, the renal veins, and the nodes between aorta and vena cava.

PREOPERATIVE ASSESSMENT OF RESECTABILITY

Computed tomographic (CT) scanning is the central investigation for the assessment of resectability in pancreatic cancer. Once metastatic disease has been excluded, the most important consideration as to resectability will be the degree of vascular involvement (Fig. 10-1). More subtle degrees of involvement can be suspected when the clear fat plane surrounding the celiac axis or the superior mesenteric artery is lost (Fig. 10-2).

Figure 10-1 Gross and obvious encroachment of the celiac and splenic arteries as seen on helical CT.

Figure 10-2 Loss of the clear fat plane around the superior mesenteric artery indicates tumor encroachment and predicts unresectability.

Arterial encroachment or encasement by adenocarcinoma of the pancreas precludes resection for cure. However, venous involvement of the superior mesenteric or portal vein does not necessarily preclude resection (Fig. 10-3). The presence of obvious enlarged varices on the CT scan almost always precludes any resection for cure. More subtle involvement of the superior mesenteric vein or the portal vein is more difficult to interpret. Nevertheless, any significant degree of venous involvement will almost always mean that there is some degree of extension of the tumor to the arteries, usually the superior mesenteric artery, by posterior encroachment behind the superior mesenteric and portal veins. Complete obstruction of the splenic vein does not preclude resection, but proximal splenic involvement raises the issue of involvement of the base of the celiac axis.

Figure 10-3 A and B, CT with axial cuts showing a pancreatic head carcinoma with involvement of less than 50% of the circumference of the superior mesenteric vein without involvement of the superior mesenteric artery (note the rim of fat tissue around the artery). Portal vein resection and reconstruction were carried out.

Magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound are used on a selective basis.

PREOPERATIVE PREPARATION

Nutritional support prior to pancreaticoduodenectomy has no impact on outcome. It is important, however, especially in the presence of jaundice to restore the patient’s fluid and electrolyte balance before operation. Significant anemia associated with a duodenal pancreatic mass suggests a duodenal adenocarcinoma.

The primary organism in postoperative infection is the same organism identified intraoperatively in contaminated bile. Polymicrobial intraoperative bile cultures are found in 70% of positive cultures. A limited bowel preparation and a single dose of preoperative systemic broad spectrum antibiotics are used.

PREOPERATIVE BILIARY DRAINAGE

Prospective randomized studies have not shown a benefit to preoperative biliary drainage by the transhepatic or by the endoscopic route. Not only are these procedures not advantageous, but they may be harmful (McPherson et al., 1984; Blenkharn et al., 1984). The placement of indwelling stents inevitably contaminates the bile, produces a peripancreatic inflammatory response, and is on occasion accompanied by severe pancreatitis (Fig. 10-4) and often cannot be justified. A highly selective use of biliary drainage for those patients in whom the delay between diagnosis and resection may be prolonged is justified.

Figure 10-4 Severe pancreatitis following unnecessary endoscopic stenting for a small periampullary lesion.

Clearly, biliary drainage has a major contribution to make in the patient with unresectable cancer and in the relief of pruritus, where resection must be delayed, or is not contemplated. Endoscopic drainage is better than percutaneous methods. Percutaneous drainage should be considered if there is cholangitis or severe complications of jaundice.

ROLE OF SOMATOSTATIN

Continuous pancreatic secretion has been considered to hinder healing of the pancreatic stump. This led to the hypothesis that by reducing the exocrine secretion, the incidence of pancreatic fistula could be reduced accordingly.

Octreotide, the octapeptide analog of somatostatin, is a powerful inhibitor of pancreatic exocrine secretion. Numerous randomized prospective trials have examined the role of prophylactic, perioperative octreotide and its impact on the outcome after pancreatic surgery (Büchler et al., 1992; Friess et al., 1995).

I believe that, as recommended by Büchler (2007) for all patients scheduled for pancreatic resections, prophylactic subcutaneous octreotide (Sandostatin), beginning with the first dose of 200 mcg given at induction, should be used. It is suggested that if the pancreas is considered high risk by the surgeon because of a soft consistency or a pancreatic duct size of less than 3 mm in diameter, the postsurgical regimen would be three daily doses of 200 mcg of octreotide for the next 5 days. Conversely, if the gland is firm with a relatively wide duct, each individual dosage would be 100 mcg.

CEPHALIC PANCREATICODUODENECTOMY (WHIPPLE OPERATION)

The procedure usually begins with a laparoscopy in an effort to determine remote metastasis and with the use of laparoscopic ultrasound to detect the presence or absence of unsuspected hepatic metastases or vascular encasement.

TECHNIQUE OF CEPHALIC PANCREATICODUODENECTOMY

A technique in common use is described. However, I prefer the variations in technique of pancreaticojejunostomy and choledochojejunostomy, which are detailed in the following (see Figs. 10-16 and 10-17) and depicted in the videos.

Figure 10-16 A, Technique for end-to-side anastomosis of the bile duct below the hilus to the jejunum. The serosa of the jejunum is sutured to the full thickness of the bile duct. B, The jejunum is incised, and the suture is now developed as a continuous anterior layer. The posterior layer of the jejunal mucosa is not sutured directly to the bile duct mucosa. Several interrupted sutures may be inserted, however, before completing the anterior layer to approximate the mucosa. Anastomosis is now completed (see also Chapter 8).

Figure 10-17 An alternative approach to the pancreaticojejunal anastomosis using interrupted “through and through” sutures placed first. Interrupted ductal sutures are placed before the “through and through” pancreatic sutures are pulled up and tied. The “through and through” sutures are tied, and the anterior ductal sutures are placed. The anterior pancreaticojejunal interrupted sutures are finally placed and subsequently tied.

Resection

If laparoscopy shows no evidence of metastatic disease or of peritoneal deposits and the laparoscopic ports have been placed appropriately in the planned bilateral subcostal incision, the incision is made. A midline incision or an extended right subcostal incision is used. The abdomen is opened and exploratory laparotomy performed. The liver is evaluated for metastases, and invasion of the transverse mesocolon is particularly examined.

The lesion is then evaluated for resectability. The colon is mobilized (Fig. 10-5) and the inferior vena cava is dissected free of all tissue. The third and fourth part of the duodenum is reflected and the pancreas elevated so that a hand can be passed behind the pancreas to palpate the tumor mass (Fig. 10-6). This usually determines whether or not the likelihood of posterior extension to the superior mesenteric artery is present. Gross invasion of the superior mesenteric artery presupposes venous encasement and unless the artery is completely free, the procedure is terminated. The omentum is elevated and the lesser sac is entered. The omentum is detached from the colon and the inferior border of the pancreas identified. The anterior surface of the superior mesenteric vein is identified (see below), and the right gastro-epiploic vein divided and the anterior branch of the inferior pancreaticoduodenal vein ligated just below the pancreas. The middle colic vessels that drain into the superior mesenteric vein may be preserved but can be divided without consequence. The presence of any significant varices in the omentum or colonic mesentery should raise concern as to portal vein or superior mesenteric vein obstruction.

Figure 10-5 The colon is mobilized from the right upper quadrant (dashed line).

Figure 10-6 The third and fourth parts of the duodenum are reflected, and the pancreas is elevated so that the hand can be passed behind the pancreas to palpate the tumor mass and the superior mesenteric vessels.

The pancreas is then elevated from the anterior surface of the superior mesenteric vein (Fig. 10-7). If this dissection plane is free and before completion of the dissection from below, attention is directed to the superior border of the pancreas, where the common hepatic artery is identified (Fig. 10-8).