Tara M. Breslin, Nora A. Janjan, Jeffrey E. Lee, Peter W. T. Pisters, Robert A. Wolff, James L. Abbruzzese, Douglas B. Evans

Pancreatic Tumor Study Group: Departments of Surgical Oncology (TMB, JEL, PWTP, DBE), Radiation Oncology (NAJ), and Gastrointestinal Oncology and Digestive Diseases (RAW, JLA), The University of Texas M. D. Anderson Cancer Center, Houston, TX

Received 6/4/98 Accepted 5/5/98

4. SURGICAL TECHNIQUE

The surgical resection is divided into six clearly defined steps (figure 3)(13):

Figure 3. Six surgical steps used to perform the pancreaticoduodenectomy operation. The pancreatic head is removed en-bloc with the distal stomach, duodenum, proximal jejunum, bile duct and gallbladder.

1. Identification of the infrapancreatic superior mesenteric vein (SMV): A Cattell-Braasch maneuver is performed by mobilizing the right colon and incising the visceral peritoneum to the ligament of Treitz (14). When complete, this maneuver allows cephalad retraction of the right colon and small bowel, exposes the third and fourth portions of the duodenum. Mobilization of the retroperitoneal attachments of the mesentery in order to facilitate exposure of the SMV is particularly important in patients who require venous resection. The lesser sac is entered by taking the greater omentum off of the transverse colon. The middle colic vein is identified, ligated, and divided prior to its junction with the SMV. Routine division of the middle colic vein allows greater exposure of the infrapancreatic SMV and prevents iatrogenic traction injury during exposure of the infrapancreatic SMV.

2. Kocher maneuver: The Kocher maneuver is begun at the junction of the ureter and right gonadal vein. The right gonadal vein is ligated and divided, and all fibrofatty and lymphatic tissue overlying the medial aspect of the right kidney and inferior vena cava is elevated with the pancreatic head and duodenum to the left lateral edge of the aorta. Palpation of the relationship of the tumor to the SMA is not used to determine resectability(15). Instead, the relationship of the tumor to the SMA and celiac axis is objectively defined by preoperative contrast-enhanced CT; our preferred technique for assessment of these vital tumor-vessel relationships.

3. Portal dissection: The portal dissection is initiated by exposing the common hepatic artery proximal and distal to the gastroduodenal artery which is then ligated and divided. Encasement of a short segment of the hepatic artery is treated with segmental resection and either primary anastomosis or a reversed saphenous vein graft. The gallbladder is dissected out of the liver bed, and the common bile duct transected just cephalad to its junction with the cystic duct. Following division of the common bile duct and medial retraction of the common hepatic artery, the anterior wall of the portal vein is exposed. We do not make any attempt (at this stage in the operation) to develop a plane of dissection between the anterior surface of the SMPV confluence and the posterior surface of the neck of the pancreas. Invasion of the lateral or posterior wall of the SMPV confluence by tumors of the pancreatic head or uncinate process can be directly detected only after gastric and pancreatic transection.

4. Gastric transection: The stomach is transected at the level of the third or fourth transverse vein on the lesser curvature and at the confluence of the gastroepiploic veins on the greater curvature.

5. Mobilization of the duodenum and proximal ligament of Treitz: The jejunum is transected approximately 10 cm distal to the ligament of Treitz and its mesentery is sequentially ligated and divided. The duodenal mesentery is similarly divided to the level of the aorta, and the duodenum and proximal jejunum are reflected beneath the mesenteric vessels.

6. Pancreatic transection and retroperitoneal vascular dissection: After traction sutures are placed on the superior and inferior borders of the pancreas, the pancreas is transected with an electrocautery at the level of the portal vein. If there is evidence of tumor adherence to the portal vein or SMV, the pancreas can be divided at a more distal location in preparation for segmental venous resection. The specimen is separated from the SMV by ligating and dividing the small venous tributaries to the uncinate process and pancreatic head. Complete removal of the uncinate process combined with medial retraction of the SMPV confluence facilitates exposure of the SMA, which is then dissected to its origin at the aorta.

The retroperitoneal dissection along the SMPV confluence and SMA represents the most important oncologic aspect of pancreaticoduodenectomy. This is due to the tendency of pancreatic adenocarcinoma to extend into the extrapancreatic retroperitoneal soft tissues and nerve sheaths adjacent to the right side of the SMA. Two specific issues regarding the dissection along the SMA warrant comment. First, this dissection should occur in the immediate periadventitial plane along the SMA. The SMA is readily identifiable within a 3- to 4-mm dense sheath of neural tissue located deep and medial to the SMV. The periadventitial plane is identified and dissection proceeds cephalad along the right anterolateral surface of the SMA, separating the perivascular soft tissues from the artery. This ensures the maximal retroperitoneal margin and also minimizes the risk of iatrogenic vascular injury. This latter point is particularly important because iatrogenic injury to the SMA or major bleeding from the friable superior and inferior pancreaticoduodenal branches can occur if dissection occurs through an imprecise plane in the lateral soft tissues to the right of the SMA. Second, the SMA may be injured once the specimen is completely freed from the SMV/portal vein and lateral traction is applied to the specimen; at this point in the dissection, the SMA is often pulled or "bowed" out to the right where it is vulnerable to injury unless dissection proceeds under direct vision of the artery.

Tumor involvement of the SMV and SMPV confluence is considered by most surgeons to be a contraindication to pancreaticoduodenectomy. However, reports of venous resection at the time of pancreaticoduodenectomy often involve patients with arterial involvement suggesting retroperitoneal tumor extension that could not be completely resected (16). In contrast, isolated involvement of the SMPV confluence without radiographically evident involvement of the SMA (figure 4) can be managed intraoperatively with resection of the involved segment of vein and vascular reconstruction (figure 5). Detailed evaluation of patients requiring venous resection and reconstruction reveals a long-term outcome that is comparable to that of similarly staged patients not requiring vascular resection (16, 17). Thus, isolated involvement of the SMPV confluence is an anatomic issue that requires a technical strategy but does not in and of itself represent an adverse prognostic factor precluding potentially curative resection.

Figure 4. Illustration of the three-dimensional relationship between a pancreatic head tumor and the superior mesenteric vein (SMV) and artery (SMA). The intimate relationship between the pancreatic head and the lateral and posterior walls of the SMV can result in venous invasion by a pancreatic head carcinoma in the absence of tumor involvement of the SMA (insert). IVC, inferior vena cava; LRV, left renal vein.

Figure 5. Illustration of our preferred method of reconstruction of the superior mesenteric vein (SMV) using an internal jugular vin interposition graft. The splenic vein - portal vein junction is usually easily preserved by tangential excision of the SMV to include a longer segment of the lateral wall of the portal vein. SMA = superior mesenteric artery.