Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure)

Transcription

1 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) Operative Indications: Pancreaticoduodenectomy, or the Whipple procedure, may be indicated for a variety of benign and malignant diseases. It is most commonly performed for one of the four periampullary adenocarcinomas arising in the head of the pancreas, the ampulla, the distal bile duct, or the duodenum. The procedure is also utilized for less common neoplasms that may arise in the head of the pancreas. These include the cystic neoplasms, both serous and mucinous cystadenomas and mucinous cystadenocarcinomas, intraductal papillary mucinous neoplasms, islet cell tumors (both benign and malignant), and solid and pseudopapillary neoplasms (Hamoudi tumor). Benign ampullary and duodenal adenomas may also occasionally require a pancreaticoduodenectomy for management. There are also a handful of rare tumors, including gastrointestinal stromal tumors and acinar cell tumors, that are treatable by pancreaticoduodenectomy. Some pancreatic surgeons feel that pancreaticoduodenectomy is the procedure of choice for chronic pancreatitis when a dilated duct is not present and a Puestow procedure, therefore, cannot be performed. It is a particularly attractive operation for chronic pancreatitis when the disease is most severe in the head and uncinate process, with less extensive involvement of the body and tail of the gland. Rarely, pancreaticoduodenectomy may be indicated for extensive pancreatic and duodenal trauma, when it is felt that duodenal repair and pancreatic drainage would be inadequate surgical management. In most instances, however, a pancreaticoduodenectomy is performed for a malignant neoplasm arising in the periampullary region. The pylorus-preserving modification of the classic Whipple procedure has become our standard, and it is utilized in over 80% of the pancreaticoduodenectomies done for neoplasms. Operative Technique: The operative procedure can be performed through either a bilateral subcostal or an upper abdominal midline incision. Once the abdomen is entered, a thorough exploration must be

2 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 285 Gastrohepatic ligament Liver Celiac axis Spleen Gallbladder Stomach Duodenum 1 carried out to detect any evidence of tumor spread outside the limits of resection. The liver is carefully examined, as are all serosal surfaces for metastatic spread or peritoneal dissemination. Ultrasound can be further used to clear the liver. In addition, lymph node spread outside the boundaries of resection should be determined (1). Involvement of the periportal and celiac axis lymph nodes used to be considered a contraindication for resection. Today, however, these areas can easily be included in the lymphadenectomy accompanying a pancreaticoduodenectomy. The root of the transverse mesocolon also should be examined to determine whether there is direct tumor extension into this area. The root of the transverse mesocolon, if involved, can often be excised along with a segment of the middle colic artery. Generally, the marginal artery of the transverse colon will continue to supply adequate blood to the transverse colon, even in the instance when a segment of middle colic artery has to be excised.

3 286 Atlas of Gastrointestinal Surgery: Pancreas 2 Stomach Kocherized duodenum Tumor Duodenum Head of pancreas Inferior vena cava v. and a. Uncinate process 3 Aorta Pancreas Once tumor dissemination has been ruled out, the duodenum is extensively mobilized. The duodenum, head of the pancreas, and tumor are generally easily elevated off the inferior vena cava and aorta. Direct extension posteriorly into these structures is very unusual. This maneuver is important, however, to be certain the tumor has not extended beyond the uncinate process to involve the superior artery. For this reason, an extensive kocherization should be performed so that one can palpate the superior artery and be reasonably comfortable that there is normal uncinate process adjacent to it (2, 3). If, upon performing this maneuver, one feels tumor extending over to and involving the superior artery, the lesion is not resectable.

4 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 287 One next needs to identify the portal vein and to be certain the portal and superior veins are not involved with tumor. The quickest way to accomplish this is to mobilize the gallbladder and divide the common hepatic duct (4). The gallbladder is no longer considered an acceptable means of decompressing the biliary tree into a jejunal loop if the tumor proves to be unresectable. The hepaticojejunostomy is the biliary bypass of choice even if a palliative double bypass is to be carried out. Therefore, the common hepatic duct can be divided early. This allows one to immediately come down upon and identify the portal vein. Gallbladder Common hepatic duct divided Common bile duct 4 Gastroduodnal a. divided 5 The next step usually involves dividing the gastroduodenal artery, passing inferiorly from the common hepatic artery (5). This vessel passes anterior to the portal vein, just at the point where the portal vein passes posterior to the duodenum and neck of the pancreas. Prior to ligating and dividing the gastroduodenal artery, it should be occluded with either a vessel loop or a bulldog clamp, to be certain that a good pulse remains in the hepatic artery. In some instances, when the celiac axis is partially or completely occluded either by atherosclerosis or the arcuate

5 288 Atlas of Gastrointestinal Surgery: Pancreas ligament, the hepatic artery is fed by the gastroduodenal artery through the arcade originating from the superior artery. In this instance, if one divides the gastroduodenal artery, there is risk of liver ischemia and necrosis, and serious lifethreatening morbidity. One therefore has to be certain that a good pulse remains in the hepatic artery before division of the gastroduodenal artery. At this point, one should also check for a replaced right hepatic artery (6) a right hepatic artery originating from the superior artery rather than from the common hepatic artery. In the past, angiography was performed to determine this anomaly prior to surgery. That is no longer felt necessary because, with great accuracy, one can easily identify a replaced right hepatic artery at the time of surgery. This vessel will be found originating from the superior artery (SMA), just after the take-off of the SMA from the aorta. The replaced right hepatic artery then passes up to the liver just lateral to, and posterior to, the biliary tree. With the use of three dimensional CT scans, this anomaly can usually be identified preoperatively. Another anomaly that is less frequent but even more difficult to recognize, is a replaced common hepatic artery off the superior artery. In this instance, a sizable vessel passes anterior to the portal vein just at the point where the portal vein passes behind the first portion of the duodenum and the neck of the pancreas (7). This is in the usual location of the gastroduodenal artery. This also has to be identified and carefully preserved, because division of this vessel would be particularly disastrous, disrupting the blood supply to the liver. Replaced right hepatic a. Replaced common heaptic a. L. hepatic a. R. gastric a. L. gastric a. Splenic a. Hepatic aa. Replaced right hepatic a. Gastroduodenal a. Gastroduodenal a. Replaced common hepatic a. (off superior a.) 6 7

6 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 289 Once the common hepatic duct and the gastroduodenal artery have been divided, one can easily dissect the anterior surface of the portal vein off the posterior surface of the neck of the pancreas (8). The insertion of a vein retractor on the neck of the pancreas will allow excellent exposure for this dissection (inset). It is unusual for veins to originate from the anterior surface of the portal vein and enter the posterior neck of the pancreas, so this dissection can often proceed fairly rapidly and bluntly, without risk. Occasionally, however, a coronary vein or a superior pancreaticoduodenal vein (vein of Belcher), will come off the anterior surface of the portal vein, and one has to be aware of these possibilities. Portal v. Neck of pancreas Portal v. v. v. 8 Neck of pancreas v. 9 a. R. gastroepiploic v. Next, the third portion of the duodenum is kocherized extensively. The first structure that is identified crossing anterior to the third portion of the duodenum is the superior vein. This is a much easier route by which to identify the superior vein, rather than going through the lesser sac. We do not enter the lesser sac during a pyloruspreserving pancreaticoduodenectomy. Once the superior vein is identified as it passes anterior to the third portion of the duodenum, its anterior surface is cleaned up under the neck of the pancreas (9). Again, the use of a vein retractor on the neck of the pancreas is helpful in exposing the superior vein for this dissection. The anterior surface of the vein is usually free of significant venous branches, except for the origin of the right gastroepiploic vein.

7 290 Atlas of Gastrointestinal Surgery: Pancreas This venous structure is almost always present, coming off the anterior, or anterior left lateral, aspect of the superior vein just below the neck of the pancreas, and has to be carefully dissected, ligated and divided. Once this large venous structure has been divided, the dissections between the portal vein from above and the superior vein from below can easily be connected (10). After this is accomplished without any evidence of direct involvement by tumor of these major structures, proceeding with the operative procedure is appropriate. Dissection of pancreatic neck off portal v. 10 Portal v. Splenic v. Dissection of pancreas off superior v. v. The first portion of the duodenum is then mobilized and dissected free, off the neck of the pancreas. It is divided with a gastrointestinal anastomosis GIA stapler (11). At times, the dissection of the neck of the pancreas off the portal and superior veins can be enhanced by dividing the duodenum at an earlier stage. Gastroduodenal a. 11 First portion of duodenum divided

8 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 291 At this point, the neck of the pancreas can be divided. We generally pass a small Penrose drain underneath the neck of the pancreas, and then, using the electrocautery, divide the gland down to the Penrose drain (12). If the pancreatic duct has been occluded by tumor, and the gland is fibrotic, this division is relatively bloodless. But if the patient has an ampullary tumor, or another neoplasm that has not obstructed the pancreatic duct, and the pancreatic parenchymal is relatively normal, care has to be taken to achieve hemostasis from a variety of bleeding vessels. Duodenum Pancreatic head Tumor Portal v. 12 Pancreas divided v. Once the neck of the pancreas has been divided, a neck margin should be sent for frozen section to be certain that the margin is free of tumor (13). 13

9 292 Atlas of Gastrointestinal Surgery: Pancreas a. First jejunal branch divided (first time) Vein of Belcher v. 14 Hepatic a. Neck of pancreas The superior and portal veins are then dissected off the uncinate process. Again, this is generally done with very little need to ligate and divide substantial vessels. The superior pancreaticoduodenal vein draining into the portal vein, also known as the vein of Belcher, is a fairly constant landmark and needs to be identified, doubly ligated and divided. In addition, more distally on the superior vein, near the inferior border of the uncinate process, the first jejunal branch is a constant landmark, arising from the right lateral border of the superior vein, and coursing around and posterior to the superior artery to the proximal jejunum, to the left of the vessels. This generally has to be ligated and divided (14). A good deal of the dissection of the superior and portal veins off the uncinate process, however, can be done gently, but bluntly. The uncinate process of the pancreas ends flush against the right lateral border of the superior artery. In most instances, the dissection and division of the uncinate process should be flush with the superior artery, cleaning approximately 180 degrees of the artery s circumference (15). There are several sizable arterial branches that have to be identified, ligated and divided. Finally, the first jejunal venous branch, as it courses underneath the superior artery to pass to the proximal jejunum, often a. has to be doubly ligated and divided for a second time (16). v. Uncinate process divided Vein of Belcher v. 15 a. 16 First jejunal branch divided (second time)

10 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 293 One then retracts cephalad the transverse colon and identifies the ligament of Treitz and the proximal jejunum. The proximal jejunum at a convenient point distal to the ligament of Treitz, in the middle of a large arcade, is divided with a GIA stapler (17). The mesentery to the proximal jejunum and fourth and third portions of the duodenum are then doubly clamped, divided and ligated with 2-0 silk. Since the third portion of the duodenum has been extensively kocherized and mobilized during the earlier part of the dissection, and since the uncinate process has been completely divided during the earlier dissection, this dissection below the transverse mesocolon to completely mobilize the specimen proceeds easily and quickly. Once the jejunum is divided and the mesentery is clamped, divided and ligated down to the ligament of Treitz, the proximal jejunum is passed underneath the superior vessels over to the right side of the abdomen, and the specimen is removed from the operative field (18). Common hepatic duct Jejunum divided Common hepatic a. Mesentery divided 17 First portion of duodenum Transverse colon 18 Duodenum Transverse colon Pancreatic head Uncinate process Jejunum

11 294 Atlas of Gastrointestinal Surgery: Pancreas Gallbladder Distal biliary tree Head and neck of pancreas The specimen consists of the distal Uncincate portion of the first part of the duodenum, all of the second, third and process fourth portions of the duodenum, and approximately 10 cm of proximal jejunum. In addition, the neck, head Duodenum and all of the uncinate process of the pancreas are included, as are the gallbladder and distal biliary tree (19). 19 Proximal There are a variety of ways to jejunum perform the pancreaticojejunostomy. Resection specimen Many have been used very effectively, with a reasonably low incidence of pancreatic leakage and with low morbidity and mortality. We prefer to invaginate the end of the pancreas into the side of the jejunum. Other pancreatic surgeons prefer to perform a duct to mucosa pancreaticojejunostomy, also in an end-to-side fashion. Whether or not to stent the anastomosis with a small polyethylene tube is still under debate. We will demonstrate the invagination technique with an end-to-side pancreaticojejunostomy (20), which also includes a duct-tojejunal mucosal anastomosis; we will also demonstrate a duct-to-mucosa anastomosis; finally, we will demonstrate teh invagination technique. The end-to-side invagination anastomosis is carried out in two layers: an outer interrupted layer of 3-0 silk and an inner continuous layer of 3-0 synthetic absorbable material. The jejunum is brought up into the lesser sac through a rent in the transverse mesocolon, generally through the bare area of transverse mesocolon that resided over the junction of the second and third portions of the duodenum. The outer row of the posterior layer is placed first. The 3-0 silks are placed through the posterior surface of the pancreas, and then through the jejunum (21). 20 Outer layer of posterior row Jejunum Pancreas Pancreaticojejunostomy 21

12 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 295 Inner layer of 22 posterior row 23 Pancreatic duct included in inner layer Inner layer oif anterior row When all sutures have been placed, they are secured. A jejunotomy is then performed. The inner posterior layer of the anastomosis consists of a continuous 3-0 synthetic absorbable suture placed in a locking fashion (22). The pancreatic duct is included in this inner layer. If it is a normal-sized duct, only two or three throws are placed through the duct. If the duct is dilated, however, several throws are placed through and through the dilated pancreatic duct. Thus, this technique combines both the invagination technique as well as a duct-to-mucosa anastomosis. The inner layer of the anterior row of the anastomosis is performed next. This consists of an over-and-over suture passing from above to below, through the capsule of the pancreas and out through the divided parenchyma, and then from inside out on the jejunum. Again, the pancreatic duct is incorporated in several throws of this inner layer of the anterior row (23). When this has been completed, the outer interrupted layer of 3-0 silk sutures is placed such that some of the jejunum is drawn over to cover the anastomosis (24). 24 Outer layer of anterior row

13 296 Atlas of Gastrointestinal Surgery: Pancreas 25 Jejunotomy (small) Jejunum Invaginated pancreas This is performed by passing the silk sutures through the capsule of the pancreas about 1 cm from the anastomosis, then out at the anastomosis, and then through and through the jejunum about a centimeter away from the anastomosis. This anastomosis results in invagination of the end of the pancreas into the side of the jejunum, utilizing two layers, and also incorporates the pancreatic duct (25). This anastomosis can also be performed in an end-to-end fashion, when the pancreatic remnant has a relatively small diameter, and the jejunal diameter is of sufficient size. The anastomosis is performed in an identical fashion as the end-to-side anastomosis. 26 Posterior duct-to-mucosa row For the duct-to-mucosa anastomosis, the outer layer is placed exactly as it is for the invagination technique. The next step creates a jejunotomy the same size and exactly adjacent to the pancreatic duct (26). The ductto-mucosa anastomosis is performed with interrupted 5-0 synthetic absorbable suture material. The posterior row is placed first, the sutures passing from inside out on the duct side and outside in on the mucosal side. Once all posterior row sutures have been placed, they are secured (27). 27

14 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 297 Stent placed in pancreatic duct and secured Anterior duct-to-mucosa row 30 Completed anastmosis Next, one can choose to place a stent or not. We demonstrate a stent created from a No. 8 French pediatric feeding tube, 8 cm in length, being secured with one of the 5-0 sutures previously placed in the posterior row (28 29). The anterior row of the duct-tomucosa anastomosis is completed by placing a row of interrupted 5-0 synthetic absorbable sutures from outside in on the duct, and inside out on the jejunal mucosa (30). The outer anterior layer is completed with an interrupted row of 3-0 silk sutures placed in a Lembert fashion (31). Stent 31

15 298 Atlas of Gastrointestinal Surgery: Pancreas 32 Finally, in the unusual situation of a very thin, soft gland in which the pancreatic duct can not be identified, we resort to placing the end of the pancreas into the end of the jejunum for a 5- cm distance and then tacking the jejunum circumferentially to the body of the gland. This is accomplished by mobilizing the end of the pancreas for a 5-cm distance and then placing stay sutures 2.5 cm from the cut end on the superior and inferior borders. These stay sutures are tied, then passed into the end of the jejunum and out the side, 2.5 cm from its end (32). When these are secured, the pancreas is inserted into the jejunum for a 5- cm distance. The end of the jejunum is then sutured to the body of the pancreas circumferentially with a series of interrupted 3-0 silk sutures (33). 33

16 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 299 Two to five centimeters distal to the pancreaticojejunostomy, the hepaticojejunostomy is performed (34). This is carried out with a single layer of interrupted 4-0 synthetic absorbable suture material. An appropriately sized enterotomy is performed, and the posterior row is placed with through-and-through sutures passing from inside out on the jejunum and outside in on the hepatic duct (35). When all sutures are placed, they are secured. The anterior layer is then carried out, again first placing all sutures before securing them. They pass from outside in on the jejunum, and inside out on the hepatic duct (36). Hepaticojejunostomy 34 Posterior row Hepatic duct Anterior row 35 36

17 300 Atlas of Gastrointestinal Surgery: Pancreas Hepaticojejunostomy Duodenojejunostomy Jejunum 37 Outer layer of posterior row The final anastomosis is an end-to-side duodenojejunostomy (37). If one leaves only a 2-cm cuff of duodenum on the pylorus, it is not necessary to preserve the right gastric artery, although this is always preferable. The right gastric artery is often small, arises from the hepatic artery, and actually joins the first portion of the duodenum. In most instances, the right gastric artery can be identified and preserved. The duodenojejunostomy is performed with an outer interrupted layer of 3-0 silk and an inner continuous layer of 3-0 synthetic absorbable suture (38). Once the outer layer of the back row of the anastomosis has been placed, these sutures are secured and an enterotomy is made on the side of the jejunum (39). First portion of duodenum Stomach Stent placed in pancreatic duct and secured 38 Enterotomy 39

18 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 301 The staple line on the first portion of the duodenum is then excised. The inner layer on the posterior row is a continuous locking suture of 3-0 synthetic absorbable material (40). This is continued onto the anterior row and placed in a Connell fashion (41). The duodenojejunostomy is completed with an outer layer of interrupted 3-0 silk sutures (42). Inner layer of posterior row Inner layer of anterior row Outer layer of anterior row 42

19 302 Atlas of Gastrointestinal Surgery: Pancreas Resection Reconstruction Gallbladder End-to-side hepaticojejunostomy Distal biliary tree End-to-side duodenojejunostomy End-to-side pancreaticojejunostomy Duodenum Proximal jejunum Tumor Pancreas When performing the pylorus-preserving Whipple procedure, a portion of the first part of the duodenum; all of the second, third, and fourth parts of the duodenum; and the proximal jejunum are resected, along with neck, head, and uncinate process of the pancreas. Also removed are the gallbladder and distal biliary tree (43). Although there are many ways to perform the reconstruction following the resection, as just demonstrated, we prefer the end-to-side pancreaticojejunostomy, the end-to-side hepaticojejunostomy, and then an end-to-side duodenojejunostomy (44). Many surgeons continue to prefer the classic Whipple, in which a hemigastrectomy is performed instead of pylorus preservation (45). 45 Alternate: Hemigastrectomy with gastrojejunostomy

20 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 303 Portal v. 47 Splenic v. v. Portal v. Veinotomy closed v. Inferior v. 46 Tumor involvement of superior v. 48 Many pancreatic surgeons also feel that, in selected patients with tumor involvement of the portal and/or superior vein (but with otherwise favorable tumors), resection of a segment of these venous structures should be performed, along with venous reconstruction. If the tumor involves just a very small area of the portal vein or superior vein, a Satinsky clamp or DeBakey clamp can partially occlude the venous structure, and a small ellipse of the vein that is involved with the tumor can be excised (46). If this ellipse is small, the venotomy can be closed with a continuous 5-0 synthetic non-absorbable suture (47). If the ellipse is larger and its direct closure would result in narrowing of the superior vein, a vein patch can be utilized to maintain diameter (48). Patch

21 304 Atlas of Gastrointestinal Surgery: Pancreas 49 Portal v. Tumor v. In some patients, enough of the vein is involved so that tangential resection is not feasible. In these instances, a segment of portal and/or superior vein generally has to be excised (49). In these instances, if the segment includes the splenic vein, the splenic vein can be ligated and divided with impunity. After the segment of superior vein and portal vein is excised, if it is 3 cm or less in length, a direct end-to-end anastomosis can be performed (50) If the segment is longer than 3 to 4 cm, an interposition vein graft of either saphenous vein or jugular vein is preferable (51). It is not necessary to reimplant the splenic vein. It has been controversial as to whether or not a retroperitoneal lymphadenectomy accompanying a pancreaticoduodenectomy is of benefit in prolonging survival after a resection for cancer of the pancreas. Some pancreatic surgeons have felt an extensive retroperitoneal dissection, as well as dissection of the nodes surrounding the celiac axis and porta hepatis, has resulted in prolonged survival. When we perform a retroperitoneal lymphadenectomy, we first perform a classic Whipple including a hemigastrectomy so that the prepyloric and pyloric lymph nodes are included. The retroperitoneal dissection then starts at the medial aspect of the right kidney hilum and proceeds laterally to the left side of the aorta. It Portal v. Portal v. End-to-end v. anastomosis Interposition vein graft v.

22 Pancreaticoduodenectomy (Pylorus-Preserving Whipple Procedure) 305 Alternative: Retroperitoneal lymphdenctomy v. Hepatic duct (clamped) Inferior vena cava Aorta Stomach a. Right kidney Inferior a. 52 extends superiorly from the portal vein to inferiorly at the takeoff of the inferior artery (52). In our experience, when retroperitoneal nodes are positive, they generally are in the caval-aortic groove. This dissection also includes the tissues surrounding 180 degrees of the circumference of the superior artery. In addition, the celiac axis lymph nodes are dissected (53), and the dissection can pass laterally along the hepatic artery into the porta hepatis. It remains controversial as to whether or not such a retroperitoneal lymphadenectomy prolongs survival. In the largest single-institution, prospective randomized study carried out, radical retroperitoneal lymphadenectomy was of no survival benefit. Retroperitoneal nodes Celiac axis nodes 53