الفهرس 
Aim of The EssayOnly 14 pages are availabe for public view
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Abstract
Morphological developmental anomalies of the liver include: agenesis, aplasia or hypoplasia. Hypoplasia of right hepatic lobe is a rare congenital anomaly that is sometimes associated with ectopy of gall bladder.
Positional anomalies of the liver include a lot of variants. Accessory lobes of the liver may be attached to the liver tissue by a mesentery.Ectopic hepatic tissue is seen frequently in the abdominal cavity attached to abdominal structures as the spleen, pancreas, and adrenal glands by mesenteries or stalks. Heterotopic liver tissue may be present above the diaphragm, butmostly connected to the liver by a small pedicle piercing the diaphragm or passing through a small hiatus.Multiple foci of heterotopic liver may present in the jejunum.
Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the celiac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60%. In general, the common hepatic artery may arise from the abdominal aorta or superior mesenteric artery (SMA), and all or part of the right and left hepatic arteries may arise from other vessels. The two commonestvariants are right hepatic artery replaced to the SMA and left hepatic artery replaced to the left gastric artery.
Defects of the portal venous system include those in which the portal vein is completely absent, has an abnormal communication or course, or is duplicated.Most affected patients have a single accessory inferior hepatic vein, although occasionally there can be two such veins.
Congenital anomalies of the bile ducts are relatively common with a reported prevalence of 15% based on surgical studies. Congenital absence of the common bile duct, the common hepatic duct emptied directly into the gallbladder; the latter drained by a long cystic duct into the second part of the duodenum. Interposition of the gall bladder is a rare, surgically correctable anomaly in which the cystic duct is absent and one or both hepatic ducts empty into the gall bladder, which in turn empties into the common bile duct.
The right hepatic duct entering the cystic duct is an anomaly that can be detected by intra-operative cholangiography. This can help to avoid any injury to the bile duct during cholecystectomy. Accessory bile ducts, often draining a segment of the right lobe of the liver into the common bile duct or the gallbladder, have been found at as many as 4% of necropsies.
Congenital doubling of the extrahepatic biliary tract, is extremely rare.
Agenesis of the gallbladder is a rare congenital anomaly occurring in 13 to 65 people of a population of 100 000. In congenital absence of the common bile duct, the common hepatic duct empties directly into the gallbladder; the latter drained by a long cystic duct into the second part of the duodenum. Cholecystectomy in these cases inevitably produces a complete defect in the biliary tract, which should be recognized and repaired primarily.
Biliary atresia is characterized by obliteration or discontinuity of the extrahepatic biliary system, resulting in obstruction to bile flow. Progressive damage of extrahepatic and intrahepatic bile ducts secondary to inflammation may occur, leading to fibrosis, biliary cirrhosis, and eventual liver failure.
Congenital cystic lesions of intrahepatic bile ducts include five entities: congenital hepaticfibrosis (CHF), Caroli’s disease, von Meyenburg complexes, simple cyst of the liver and polycysticliver disease.In CHF and polycystic liver disease, renal abnormalities are frequently observed.
Cystic dilatation of the extrahepatic bile ducts is known as choledochal cyst (CDC). It is morecommonly encountered in Japan and Asia. Most of the classifications describe six anatomicaltypes of CDC. Type I:saccular or fusiform dilatation of extra hepatic biliary radicles(EHBR), Type II: diverticulum of EHBR, Type III:choledochocele, Type IV: multiple cysts of the intra- or extrahepatic ducts (or both), Type V: single or multiple intrahepatic cysts (Caroli’s disease) and Type VI: An isolated cyst of the cystic duct is an extremely rare lesion.
Congenital anomalies and anatomical variations of extra- hepatic biliary tree though are not common but can be of clinical importance and surprise if present. It is important to emphasize that it is difficult to obtain the diagnosis of these malformations pre-operatively by investigations utilized for diagnosis of gallbladder disease; however, they can be seen by special radiological evaluation. The use of laparoscopy for gallstone disease with high resolution and magnification reveals clear anatomy of biliary tree as compared to open cholecystectomy. Therefore extra-hepatic biliary system can easily be assessed for its anatomical variations and congenital anomalies during laparoscopic cholecystectomy. So every surgeon should assess for these anomalies during laparoscopic cholecystectomy in order to prevent inadvertent ductal clipping, ductal injuries, strictures and bleeding problems. Awareness of these anomalies will decrease morbidity, conversion and re-exploration in these patients.