When the procedure is carried out for an inflammatory lesion of the body and tail of the pancreas, a direct exploration of this region is performed. When the procedure is carried out for tumor, a thorough exploration of the abdomen, with particular reference to the liver and the gastrohepatic ligament in the region of the celiac plexus, should be made for evidence of metastasis. A possible microscopic diagnosis of adenocarcinoma is sought by biopsy before proceeding with a total pancreatectomy from the left-side approach. Since the adenomas can be distributed throughout the pancreas, the head of the pancreas must be thoroughly explored by visualization and palpation preliminary to a definitive type of procedure on the left half of the pancreas. Evidence of gastric hypersecretion, as indicated by increased vascularity and thickening of the gastric wall, along with a hyperemic and hypertrophic duodenum and an ulcer in the duodenum or beyond the ligament of Treitz, adds support to the potential diagnosis of gastrinoma tumor of the pancreas. Likewise, the inner wall of the duodenum should be carefully palpated in the search for small adenomas extending into the lumen of the duodenum from the pancreatic side. Finally, a sterile ultrasound probe for intraoperative scanning of nonpalpable lesions is advocated by most surgeons.
After the abdomen has been explored and the region of the head of the pancreas evaluated, the greater omentum is reflected upward, and downward traction is maintained on the transverse colon as the omentum is separated by sharp dissection and the lesser sac entered (figure 1). Usually, the stomach is easily separated from the pancreas, but sharp dissection may be required to separate it from the capsule of the pancreas, especially if there have been repeated bouts of acute inflammation. Sharp as well as blunt dissection is used to sweep the posterior gastric wall away from the pancreas, particularly in the region of the antrum, to make certain the middle colic vessels have not been angulated upward and attached to the posterior gastric wall. A clear view must be ensured of the entire pancreas and the first part of the duodenum all the way over to the hilus of the spleen (figure 1). To avoid troublesome bleeding, it is usually desirable to divide the communicating vein between the right gastroepiploic vessels and the middle colic vein inferior to the pylorus. This permits better mobilization in the region of the antrum. Large S retractors can be used to retract the stomach upward as the transverse colon is either pulled downward outside the wound or returned to the abdomen and packed away. The pancreas should be inspected thoroughly and palpated to verify the pathology. It is safer and far easier to mobilize and remove the spleen rather than attempt to separate the pancreas from the splenic artery and vein running along the superior surface of the body and tail of this organ.
In carcinoma the tumor’s mobility and the presence or absence of regional metastasis must be determined before a radical resection is planned. It is less uncommon to find a resectable carcinoma involving the tail or body of the pancreas. In insulinomas it is more common to find only one tumor; this may be enucleated without removing a large segment of the pancreas, depending on the adenoma’s location and relationship to the major pancreatic duct and vessels. Finding a solitary gastrinoma of considerable size may tempt the surgeon to do a local excision only, followed by vagotomy, pyloroplasty, and proton pump inhibitor therapy postoperatively. Any enlarged lymph nodes around the pancreas are excised for frozen section examination searching for evidence of metastases. For gastrinoma, the duodenum must be opened and explored to search and remove a possible duodenal primary lesion.
When the lesion cannot be seen or palpated by digital examination of the anterior surface of the gland, the body and tail must be mobilized for direct palpation with the thumb and index finger and for visualization of the under-side of the pancreas. This is accomplished by incising the peritoneum along the inferior surface of the pancreas (figure 2). Only a few small blood vessels are encountered. The inferior mesenteric vein should be identified, and the incision should avoid it as well as the middle colic vessels. After the inferior surface of the peritoneum has been incised, a finger can be introduced rather easily underneath the pancreas, and the substance of the gland can be palpated quite easily between the thumb and index finger (figure 3). As a matter of fact, the finger can be inserted completely around the pancreas following the incision in the peritoneum just above the splenic artery and vein. Finally, a hand-held ultrasound unit is very useful in finding nonpalpable lesions within the pancreas.
In the presence of a tumor that necessitates removal of the left half or all of the pancreas, steps should be taken to mobilize and remove the spleen. The splenic artery is doubly ligated with 00 silk near its point of origin. This tends to decrease the blood loss following manipulation of the spleen and permits blood to drain from this organ into the systemic circulation during the subsequent steps of its removal. The left gastroepiploic vessel is doubly clamped and ligated, and the short gastric vessels are then divided all the way up to the diaphragm. The blood supply on the greater curvature should be ligated by transfixing sutures that incorporate a bite of the gastric wall to prevent hemorrhage if gastric distention should occur and the ligature slip off the gastric side (figure 4). Alternatively, the ultrasonic dissector can be used to coagulate and divide the short gastric vessels. The splenorenal ligament is divided as the surgeon pulls the spleen medially with his left hand (figure 5). Blunt and sharp dissection may be carried out to free the tail of the pancreas, but this is rather easily done by finger dissection as the organ is reflected medially (figure 6). The left adrenal and kidney are clearly visualized as well as a segment of the left renal vein. The inferior mesenteric vein is ligated and divided (figure 6) at the inferior border of the pancreas. The splenic artery is divided near its point of origin and ligated and then transfixed distally with double ties of 00 silk. The splenic vein is cleared and separated from the posterior surface of the pancreas and is followed over to the point where it joins the superior mesenteric vein to form the portal vein (figure 7). The splenic vein is gently freed from the pancreas, using blunt-nosed right-angle clamps (figure 7). The vessel is ligated and is transfixed proximally to this tie to avoid any possible late hemorrhage. The spleen and body of the pancreas can then be mobilized sufficiently to be brought outside the peritoneal cavity.
This approach is useful in performing a total pancreatectomy since it ensures a good exposure for the identification of veins coming off the medial aspect of the portal vein. The superior surface of the portal vein is free of venous tributaries. However, the resection may be restricted due to involvement of the portal vein by adenocarcinoma.
After the spleen and the tail of the pancreas have been mobilized outside the peritoneal cavity, the entire pancreas is palpated once again for evidence of tumor involvement. The pancreas can be divided with electrocautery to the left of the portal vein or, if need be, even to the right side of the portal vein, provided that a finger has been introduced between the vein and the pancreas to free its anterior margin (figure 8).
The surgeon usually finds it advisable to make multiple serial sections of the pancreas in searching for additional adenomas and in determining whether his line of incision is free of tumor. Frozen section consultations may be obtained, although pancreatic tissue is difficult to evaluate under these circumstances, and the final diagnosis may have to be delayed until the permanent sections have been made.
The cut end of the pancreas is examined and the pancreatic duct is identified. The pancreatic duct is closed with a 0000 nonabsorbable monofilament suture (figure 9a). The end of the pancreas is closed with interrupted overlapping 000 silk sutures of the mattress type (figure 9b). Additional sutures are taken, particularly where there is persistent bleeding (figure 10). Alternatively, the pancreas may be divided and secured with staples using a linear stapler.