Plate 131

When the second and third parts of the duodenum are well mobilized, the surgeon may or may not have proved the presence and the extent of a tumor. Additional information can be obtained by palpating the head of the pancreas between the thumb and index finger (Figure 7). It should be remembered that pancreatic adenomas are occasionally found extending into the wall of the duodenum on the inner curvature side. The presence of a tumor involving the lower end of the common duct, and particularly ulceration with tumor involvement in the region of the ampulla of Vater, may be verified by palpation. A major concern when a tumor is felt or visualized is to determine whether it is a benign or malignant lesion and whether the portal vein is involved. Unless the surgeon is skilled in potential resection and repair of the portal vein, there should be good evidence that the tumor does not extend into or about the portal vein before deciding to proceed with the radical extirpation of the head of the pancreas.

It is not unusual to have considerable difficulty in proving the presence or absence of a malignant tumor deep in the head of the pancreas that is producing an obstructive jaundice. A surgeon is often reluctant to mobilize the head of the pancreas adequately and to carry out a biopsy to prove the presence of tumor because of potential complications, such as hemorrhage or a pancreatic fistula and because of the poor accuracy of frozen section in differentiating between adenocarcinoma and chronic pancreatitis. A transduodenal needle biopsy is utilized by some to obtain sufficient material for frozen-section diagnosis. Proof of the diagnosis may not be possible before proceeding with pancreaticoduodenectomy. The surgeon must use his judgment to establish a reasonable diagnosis based on the gross findings. If the lesion is not resectable and palliation is to be provided by such surgical procedures as cholecystoenterostomy and gastroenterostomy, chemotherapy, and radiotherapy, then microscopic proof of cancer diagnosis is required. It permits a more rational plan for the patient's care, which may extend over a long period. The surgeon must decide whether the best approach for the biopsy of the tumor is anterior or posterior (Figure 8). A biopsy needle, such as the large Tru-cut type, can be inserted into a deep-seated tumor and biopsies taken. If the pathologist is hesitant to provide a diagnosis from the minimal amount of tissue available, the surgeon must consider the possibility of proceeding with a wedge biopsy using a small knife blade (Figure 9). Alternatively, he may send additional needle biopsies for permanent histology, which is more accurate than frozen section.

A small blade can be used to remove a wedge of tumor and the adjacent tissue compressed together with a transfixing suture of 00 silk on French needles. All bleeding must be controlled. This is not believed to be particularly dangerous provided that the sutures are not placed so deeply as to obstruct the major pancreatic duct. Next, the surgeon should proceed with further mobilization of the pancreas by entering the lesser sac (Figure 10). The omentum is retracted upward and the incision made into the lesser sac for more thorough evaluation of potential metastases above the pancreas and about the region of the celiac axis. Since some tumors of the pancreas are multiple, it is important that the entire pancreas be visualized and palpated, especially if a diagnosis of gastrinoma has been considered. It is usually advisable to open the lesser sac completely by freeing the omentum from the underlying transverse colon all the way over to and including the region of the splenic flexure of the colon (Figure 11). It should be kept in mind that the blood vessels to the colon may be angulated upward and attached for several centimeters to the undersurface of the mesocolon. The incision, therefore, should be made several centimeters away from the visualized bowel wall, as shown in Figure 11. It may be necessary to free the spleen, especially during the exploration of the pancreas for islet cell adenomas. Next, the surgeon explores the structures above the first part of the duodenum (Figure 12). The contents of the enlarged gallbladder can be aspirated if exposure is limited. The peritoneum is incised over the superior border of the duodenum, which is an initial step in isolating the common duct from the adjacent vascular structures.

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