Fetal Topographical Anatomy of the Pancreatic Head and Duodenum with Special Reference to Courses of the Pancreaticoduodenal Arteries

PURPOSE: The purpose of this study is to provide better understanding as to how the "double" vascular arcades, in contrast to other intestinal marginal vessels, develop along the right margin of the pancreatic head. MATERIALS AND METHODS: In human fetuses between 8-30 weeks, we described the topographical anatomy of the vessels, bile duct, duodenum as well as the ventral and dorsal primordia of the pancreatic head with an aid of pancreatic polypeptide immunohisto-chemistry. RESULTS: The contents of the hepatoduodenal ligament crossed the superior side of the pylorus. Moreover, the right hepatic artery originating from the superior mesenteric artery ran along the superior aspect of the pancreatic head. An arterial arcade, corresponding to the posterior pancreaticoduodenal arteries, encircled the superior part of the pancreatic head, whereas another arcade, corresponding to the anterior pancreaticoduodenal arteries, surrounded the inferior part. The dorsal promordium of the pancreas surrounded and/or mixed the ventral primordium at 13-16 weeks. Thus, both arterial arcades were likely to attach to the dorsal primordium. CONCLUSION: The fetal anatomy of the pancreaticoduodenal vascular arcades as well as that of the hepatoduodenal ligament were quite different from adults in topographical relations. Thus, in the stage later than 30 weeks, further rotation of the duodenum along a horizontal axis seemed to be required to move the pylorus posterosuperiorly and to reflect the superior surface of the pancreatic head posteriorly. However, to change the topographical anatomy of the superior and inferior arterial arcades into the final position, re-arrangement of the pancreatic parenchyma might be necessary in the head.

[Prospects for standardization of surgical procedures for carcinoma of the pancreas].

Since physicians need to guarantee the efficacy of medical therapy for patients, therapies for patients with cancer should be standardized to some extent. Carcinoma of the pancreas has the highest death rate of all cancers, with a resection rate as low as about 25% to 30% and a 5-year survival rate of around 9%. It is very difficult in such a situation to standardize the surgical strategy for carcinoma of the pancreas. Because pancreatic cancer is a general disease, the treatment strategy should include not only complete surgical resection but also local control methods with intraoperative radiation, prevention of liver metastasis, development of effective anti-cancer drugs, etc. Major progress in therapy for pancreatic carcinoma may be expected in the near future by with the cumulative use of effective therapies. Standard resection and extended resection: For carcinoma of the head of the pancreas, pancreaticoduodenectomy with regional lymph node dissection is performed in Japan, as is extended resection with thorough lymph node dissection of the retroperitoneal and paraaortic region. However, so far the prognosis of patients who undergo extended resection is not better than those who undergo standard resection. A randomized controlled trial of the two types of resection is now being conducted and its results are awaited. For carcinoma of the body and tail of the pancreas, distal pancreatectomy and splenectomy with lymph node dissection is performed if hematogenous or massive lymph node metastasis or direct invasion of the large vessels has not occurred. The Appleby procedure is performed in some cases. Reconstruction and complications of surgical procedures of carcinoma of the pancreas: It appears that a decrease in complications and a lower death rate have been achieved due to pancreaticoduodenectomy rather than due to the extent of lymph node dissection. In particular, progress in anastomosis techniques of the pancreas and intestine and in perioperative control has been marked. For prevention of complications, it is important that absorbable synthetic sutures be used in the pancreaticojejunal anastomosis, that the cut end of the pancreas be sutured and covered by the jejunum without dead space, and that the stent tube be inserted into the main pancreatic duct. The pancreaticojejunal anastomosis should be bordered by the greater omentum. This technique will prevent both the spread of the pancreatic juice into the intraabdominal cavity and rupture of the blood vessels, which can cause fatal postoperative bleeding. Sufficient intraabdominal drains should be in place, especially around the pancreaticojejunal anastomosis. Radiochemotherapy: There are no effective anticancer drugs for the treatment of carcinoma of the pancreas. It was reported that low-dose 5-fluorouracil and cisplatin (5-FU and CDDP) and gemcitabine plus either 5-FU, epirubicin, or CDDP has some effect. The efficacy of intraoperative radiotherapy has not been confirmed. It is not apparent whether radiochemotherapy is superior to surgery. Curable pancreatic carcinoma: Intraductal papillary-mucinous tumors of the pancreas (IPMT) take their name from the histological feature of mucin production and correspond to so-called mucin-producing tumors of the pancreas. This tumor is classified into two types, the main pancreatic duct type and the branch type. About 90% of the main pancreatic duct type and 20% of the branch type are malignant. The branch type of IPMT resembles a bunch of grasps in imaging procedures. Approximately 60% of cases with the branch type of IPMT can be followed up without surgery. Since the prognosis of IPMT is fairly good and the 5-year survival after surgery is about 70% to 80%, limited resection of the pancreas with organ preservation is under investigation. Mucinous cystic tumors of the pancreasin are characterized by development in the body and tail of the pancreas in middle-aged women, with histological ovarian-type stroma in the wall of the tumor, and round cystic lesions with a fibrous capsule containing multiple cystic components of various sizes, which resembles a Chinese citron upon imaging procedures. Surgery should be performed if such a diagnosis is made.