Morphological Study Of Meso-hepatopancreaticoduodenum

Background and objectivePancreatic cancer has a high degree of malignancy,among which pancreatic head cancer was easy to be accompanied by liver metastasis.At present,the surgical treatment based on the anatomy of mesopancreas was one of the research hotspots.The goal of complete resection of local tumors could be achieved by the total mesorectal resection based on "mesorectum"."Mesopancreas" was first proposed by German scholar Gockel,who believed that the complete resection of pancreatic tumors based on mesopancreas was closely related to the postoperative survival rate of patients.Some scholars have further proposed the concepts of "mesopancreas triangle" and "mesopancreatoduodenum".However,the existence of the mesopancreas has been controversial,and the scope of lymph nodes and nerves dissection have also been divergent.To patients of pancreatic head cancer with liver metastases,whether primary and metastatic lesions be treated surgically was still controversial.From the perspective of embryology,the liver,pancreas,and duodenum were a ll surrounded by the same capsule.With the development of liver and pancreatic buds,also with the translocation of the original digestive tract,the capsule of th e liver,pancreas and duodenum as a whole also had a corresponding transpositio n.In adulthood,the terms describing the capsule structure on the surface of the liver and pancreas are not consistent with the origin of capsule structure develop ment.Clinically,pancreatic cancer was often accompanied by liver metastasis.Th e capsule structure on the surface of liver,pancreas and duodenum should be re garded as a whole.We have named it meso-hepatopancreaticoduodenum.In this study,through gross anatomy and histological staining,the capsule of the pancrea s head,especially the meso-hepatopancreaticoduodenum,were observed.The purp ose was to prove the existence of meso-hepatopancreaticoduodenum and to clarif y the relationship between meso-hepatopancreaticoduodenum and surrounding orga ns or structures.It was hoped to provide basic anatomical support for clinical pr actices.Materials and methods 1.Gross anatomy.Gross anatomy of the abdomen of 30 formalin-fixed adult specimens.The main purpose of this study was to observe the morphology of the liver capsule,hepatoduodenal ligament,pancreaticoduodenal capsule formed by the peritoneum and the relationship with the surrounding structure.2.Histology.(1)Transverse specimens.One fetal specimen at 12 weeks of pregnancy was decalcified for horizontal sectioning.Six frozen adult specimens fixed with formalin were transected from the 10 th thoracic vertebra to the 4th lumbar vertebra as a whole,and anatomical structures in each section was identified.(2)Masson staining.Local samples were taken from one fetal specimen and six adult tomographic specimens.After paraffin embedding,and sectioning,Masson s taining were performed to observe the relationship between meso-hepatopancreatic oduodenum and the surrounding structures.(3)Bielschowsky silver staining.The nerves distribution of the surrounding structures of mesopancreas was observed after local samples were taken from six adult tomographic specimens.Results 1.Gross anatomy.Except the bare area of the liver,the capsule on the surface of the liver completely surrounded the liver and continues to form the lesser omentum at hilum of the liver.The hepatoduodenal ligament continued to surround the pancreatic head and duodenum downward.So,the anterior and posterior capsule of pancreaticoduodenum were formed.The posterior capsule of pancreaticoduodenum and the parietal peritoneum on the posterior abdominal wall fused with each other at the omental foramen to form a capsule bridge.The hepatoduodenal ligament contained the proper hepatic artery,and the pancreaticoduodenal capsule contained the gastroduodenal artery.2.Histology.(1)Masson staining.In the fetal specimen,the liver bud and foregut were completely surrounded by a continuous capsule.The ventral pancreatic bud and the foregut were also surrounded by the same capsule as a whole structure,and there was an obvious gap between the dorsal pancreatic bud and the foregut capsule.In adult specimens,pancreatic head was closely adhered to the descending part of the duodenum,and the anterior and posterior capsule of the hepatoduodenal ligament continued downward to enclose the pancreatic head and duodenum.The anterior capsule and posterior capsule of the head of pancreas and duodenum were formed respectively.There existed obvious gaps with the adjacent inferior vena cava and colon.At the root of the celiac trunk near the head,the posterior capsule of the pancreas extended from the posterior surface of the pancreas to the left and straddled the celiac trunk.Near the end of the celiac trunk,the posterior capsule of the pancreas was incomplete and fused with the nerves and connective tissues in front of the abdominal aorta.(2)Bielschowsky silver staining.The nerve bundles at the left side of the root of the celiac trunk were more dense than that of the right side.The posterior capsule of pancreaticoduodenum straddled the celiac trunk near the root and merged with the celiac trunk far away.The nerve bundles at the root of the superior mesenteric artery were dense.From the root to the end of the celiac trunk,the nerve bundles became loose.Conclusion 1.The peritoneum covered the surface of liver,upward,and enclosed the head o f pancreas and duodenum downward,The middle part was hepatoduodenal ligam ent which form the above structures as a whole.There could be regarded as me so-hepatopancreaticoduodenum.2.The meso-hepatopancreaticoduodenum might be a part of the meso-hepatopancr eaticoduodenosplenogastrom.It was composed of two sub mesentery structures wi th the common hepatic artery as its root.One was the liver mesentery which had the proper hepatic artery as its root and the other was meso-pancreatoduodenu m which had the gastroduodenal artery as its root.