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Pancreatic and periampullary resection
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. 1.42 ). 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 (see 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 the aorta and vena cava.
Preoperative assessment of resectability
Computed tomographic 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. 11.1 ). 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. 11.2 ).
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. 11.3 ). The presence of obvious enlarged varices on the computed tomography (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.
Magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound are used on a selective basis.
Preoperative preparation
Nutritional support before 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 endoscopic route. Not only are these procedures not advantageous, but they may be harmful ( ; ). The placement of indwelling stents inevitably contaminates the bile, produces a peripancreatic inflammatory response, and is on occasion accompanied by severe pancreatitis ( Fig. 11.4 ) 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.
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 ( ; ).
I believe that, as recommended by ) 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. 11.16 and 11.17 ) and depicted in the videos.
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. 11.5 ), 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. 11.6 ). This usually determines whether 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 later), 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.
The pancreas is then elevated from the anterior surface of the superior mesenteric vein ( Fig. 11.7 ). 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. 11.8 ).
The magnitude of the common hepatic artery pulsation is consciously examined to avoid a median arcuate ligament syndrome. The gastroduodenal artery is identified, and if there is no adherence or encasement of the common hepatic artery, the gastroduodenal artery is doubly ligated and divided, as is the right gastric artery (see Fig. 11.8 ).
This approach provides excellent access to the superior part of the portal vein above the superior border of the pancreas (see later). The portal vein can then be dissected superiorly, retracting the common hepatic artery up to its bifurcation, to the patient’s left, and isolating the common hepatic duct. The gallbladder is then mobilized and reflected down such that it is attached only by the cystic duct. Alternatively, if the gallbladder is in any way difficult, the cystic artery can be divided and the gallbladder removed. The common bile duct is not divided at this stage (see later). At some point after this dissection, a decision as to whether to take a biopsy from the pancreas should be made (see later).
The ligament of Treitz is then mobilized. Small branches of the jejunal vascular arcade of the most proximal part of the jejunum are ligated and divided. A stapler is used to transect the bowel ( Fig. 11.9 ). The small portion of the divided proximal jejunum beyond the ligament of Treitz can usually be quite safely mobilized and passed behind the mesenteric vessels.
In a standard procedure the omentum is completely divided to the border of the stomach. The stomach is then isolated and divided ( Fig. 11.10 ). The divided stomach is then reflected to the patient’s right and the common hepatic duct divided just above the entrance of the cystic duct. A bile culture is obtained.
In patients suspected of having a distal bile duct carcinoma, a frozen section is obtained at the transection site. Careful attention is paid to the variations of arterial anatomy (see “General Principles and Preoperative Approaches”).
The dissection continues down the side of the remaining portion of the common duct, taking all the tissue from the retroperitoneum at this site. Stay sutures are placed in the inferior and superior border of the pancreas, and then the pancreas is divided sharply with the knife so as to have a cleanly divided pancreatic mucosal division for subsequent suture ( Fig. 11.11 ) (see later). The portal vein is retracted so that the operating surgeon can dissect along the right side of the superior mesenteric artery with direct vision. On the theoretical possibility of contamination of the intraperitoneal wound with malignant cells from the pancreatic duct, the dividend pancreatic duct is sutured on the specimen side.
The uncinate process is then reflected from behind the superior mesenteric vein, if this has not been performed earlier in the procedure (see later). It is often easier to commence this dissection from above, identifying the origin of the superior mesenteric artery and then dissecting along the right side wall of the artery, to gain a clean dissection of all tissue running behind the portal vein. There is often adherence in the corner between the posterior-lying mesenteric artery and the anteriorly placed superior mesenteric-portal vein. On occasions, the portal vein will need to be resected (see later). The specimen is removed. A decision must now be made as to frozen section of the divided pancreas (see later).
Reconstruction
An end-to-side choledochojejunal anastomosis is carried out ( Fig. 11.12 ). The duct is clearly identified and held by a fixation stitch, which is placed at the left corner of the duct, an incision is made in the serosa of the bowel, and a lesser incision made in the mucosa. A running everting posterior layer is designed to prolapse mucosa of the bowel into the bile duct. An anterior layer is performed in a direct over-and-over fashion. A direct mucosa-to-mucosa anastomosis of the pancreatic duct to the side wall of the jejunum is then made. First, a posterior layer of running or interrupted 4-0 PDS sutures are placed to attach part of the posterior aspect of the pancreas to the side wall of the jejunum. The serosa is then scored on the jejunum, and a single posterior duct-to-mucosa stitch of 5-0 monofilament suture is placed. The mucosa is incised with a small opening, and an interrupted 5-0 duct-to-mucosa anastomosis is completed. It is rare that even the smallest duct cannot accommodate three interrupted sutures at 2, 6, and 10 o’clock ( Fig. 11.13 ). Anterior running sutures are used to invaginate the anterior pancreatic capsule into the side wall of the jejunum. Stents are rarely used.
A standard antecolic gastrojejunostomy is then created using a running 3-0 PDS suture ( Fig. 11.14 ). A peripancreatic drain is placed.
Variations in technique
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