Periampullary Lesions
It is beyond the scope of this chapter to describe in detail the operative steps in all of the potential resections. However, it is of benefit for all clinicians that take care of patients with periampullary and pancreatic neoplasms to understand the basic steps of pancreaticoduodenectomy and distal pancre-atectomies, as these operations are commonly performed. Additionally, it is important for all clinicians involved to understand the potential limitations of the operation and why patients are deemed unresectable. Resections of periampullary neoplasms are usually accomplished with pancreaticoduodenectomy. Patients are sometimes explored first with the intent of trying a transduodenal ampullectomy and/or bile duct exploration for small and superficial lesions thought to have a high chance of being benign and/or to rule out stone disease. The decision to proceed with pancreati-coduodenectomy can be made at the time of the transduo-denal procedure, depending on the operative findings or frozen sections.
Once the decision has been made to proceed with a pan-creaticoduodenectomy, exposure is accomplished either through a vertical midline or a bilateral subcostal incision. The first portion of this procedure is devoted to assessing the extent of disease and resectability. There is debate as to the benefits of staging laparoscopy versus open staging in anticipation of surgical resection or palliation. At open exploration, the entire peritoneal cavity is assessed for the presence of metastases not seen by preoperative imaging in studies. Tumor-bearing nodes within the resection zone do not contraindicate resection because long-term survival is sometimes achieved with peripancreatic nodal involvement. An extensive Kocher maneuver is performed by elevating the duodenum and head of the pancreas out of the retroperitoneum and into the midline, allowing the visualization of the SMA at its origin at the aorta. The porta hepatis is assessed by mobilizing the gallbladder out of its fossa and dissecting the cystic duct down to the junction of the common hepatic and common bile duct. The hepatic artery is also assessed to determine that it is free of tumor involvement.
If the intraoperative assessment reveals localized disease without tumor encroachment upon resection margins, the resection is performed in relative standard fashion. If assessment reveals evidence of local tumor extension giving the early impression of unresectability, the normal sequence for performing the pancreaticoduodenectomy is modified so that the easiest and safest portions of the resection are performed first, and the more difficult portions are performed later. In cases with localized disease without tumor encroachment upon resection margins, the distal common hepatic duct is divided close to the level of the cystic duct entry site early during the operation. The gastroduodenal artery is next identified and divided. For a pylorus-preserving pancreati-
coduodenectomy, the proximal gastrointestinal (GI) tract is divided 2 to 3 cm distal to the pylorus with a linear stapling device. A plane is then formed between the neck of the pancreas and the underlying anterior surface of the portal vein. For a classic Whipple procedure, a 30 to 40% distal gastrectomy is performed using a linear stapling device (Figure 141-1). The GI tract is divided distally at a point of mobile jejunum, typically 20 cm distal to the ligament of Treitz. The proximal jejunum is then separated from its mesentery and delivered dorsal to the superior mesenteric vessels from the left to the right side. The SMV caudal to the neck of the pancreas is identified while performing an extensive Kocher maneuver. The plane anterior to the SMV is developed under the neck of the pancreas. The neck of the pancreas is then divided. The specimen now remains connected by the head and uncinate process of the pancreas. These structures are separated from the portal vein, SMV, and SMA. With these areas dissected, the specimen is removed and the pancreatic neck margin, uncinate margin, bile duct margin, and duodenal or gastric margin are analyzed by intraoperative frozen section to confirm that they are free of tumor.
There are multiple options for reconstruction after pan-creaticoduodenectomy. Most commonly the reconstruction first involves the pancreas, followed by the bile duct, ant then the duodenum. The issues and controversies surrounding the pancreatic and biliary reconstruction are outlined by multiple papers specifically addressing these issues. In brief, the pancreatic anastomosis can be performed to the jejunum or to the stomach. If the jejunum is used for reconstruction, some groups favor a separate Roux-en-Y reconstruction for pancreas or even a double Roux-en-Y reconstruction for the pancreas and bile duct. Controversy continues regarding the best type of pancreaticojejunos-tomy, the importance of duct-to-mucosa sutures, and the use of pancreatic duct stents. At the Johns Hopkins Hospital, the pancreatic reconstruction is typically performed with an end-to-end or end-to side pancreaticoje-junostomy to the proximal jejunum brought through a defect in the mesocolon to the right of the middle colic artery. The biliary anastomosis is typically performed with an-end-to-side hepaticojejunostomy approximately 10 to 15 cm distal from the pancreaticojejunostomy. If the patient has a percutaneous biliary stent, then this is left in place, traversing the anastomosis. The third anastomosis performed is the duodenojejunostomy in cases of pylorus preservation, or the gastrojejunostomy in patients who have undergone classic pancreaticoduodenectomy. This anastomosis is typically performed downstream from the hepaticojejunostomy, either proximal or distal to the segment of jejunum traversing the defect in the mesocolon. Figure 141-1 depicts the resection specimen and reconstruction after a pylorus preserving and classic pancreati-coduodenectomy. After reconstruction is completed, closed suction drains are left in place to drain the biliary and pancreatic anastomosis. Some groups prefer not to place closed suction drains, accepting that if a fluid collection becomes clinically evident postoperatively, percutaneous drainage by interventional radiology may be required.
- FIGURE 141-1. Classic pancreaticoduodenectomy (A) and pylorus preserving pancreaticoduodenectomy (B). From Yeo and Cameron, 1988.
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