Radiological and Surgical Oriented Anatomical Study of "Variations in Extrahepatic Biliary Ductal System and Its Related Vessels" with its Clinical Implications.

The analysis of extrahepaticbiliaryductal system and its related vessels by studying under various methods are concluded as follows. Extrahepatic union of right and left hepatic ducts to form the common hepatic duct was noted in 62.5% of cases, which appeared to be more common than intrahepatic union. Cystic duct joins the common hepatic duct as angular type of union in 75% of cases. Cysticduct joins the common hepatic duct at a point in which it, makes common hepatic duct shorter and common bile duct longer. This is consider as normal level of union. The average length of the ducts observed in the study are cysticduct 2 - 4 cms, common hepatic duct 2 - 3 cms and common bile duct 5 - 8 cms. The arrangement of structures in hepatoduodenal ligament was that, common bile duct lies anterior and to the left of the ligament, hepatic artery lies anterior and to the right of duct system and portal vein larger and posterior to these structures. The frequency of occurrence of accessory ducts was 22.5%. The most commonly occuring ductal variations is presence of accessory right hepatic ducts terminating any where in common hepatic duct. Cystic artery arising from the coeliac right hepatic artery is seen inside the calot's triangle dividing into superficial and deep branches to supply the respective surfaces of gall bladder is noted to be the commonest arrangement. Right hepatic artery arises from hepatic proper and seen to the left side of duct system. Both cystic and right hepatic arteries passing posterior to the common hepatic duct to reach the calot's triangle is seen to be more common. Hence, many variations has established in this region and understanding of these variations is undoubtedly responsible for surgeons and radiologist. Starting from open cholecystectomy to recent advances like Living donar liver transplantation with duct to duct anastomosis (LDLT), grading of tumours like hilar cholangiocarcinoma and recent investigations like Magnetic Resonance Cholangiopancreatography (MRCP), requires definitive knowledge of the anatomy of the ductal system. Hence, I believe this study is not only pertained to anatomy, but definitely be a useful guideline for operating surgeons and radiologists.