Variations of liver's vascular structures and bile ducts

Identification of anatomy of liver's vascular structures and biliary ducts is crucial for liver transplantation or liver resection surgery. Having knowledge of the anatomy of these structures of the liver is very important for planning the surgery procedure and the success of the surgery, and finally for the patients' health. Today, liver transplantation is performed either from deceased donors or from living donors. The variations of proper hepatic artery, portal vein, hepatic veins and biliary ducts should be well known in liver transplantation procedures. We determined the MRCP (Magnetic Resonance Cholangiopancreatography) and Abdominal CT (Computed Tomography) datas of 200 patients who were admitted to Dicle University Medical Faculty between 01.01.2012 and 01.06.2016. PACS (Picture Archiving and Communications System) was used for screening the patients' data. The patients were excluded who had previous liver resection, congenital anomalies, liver tumors, Hydatid cyst disease. We determined the anatomic variations of proper hepatic artery, portal vein, hepatic veins and bile ducts. One hundered and six patients (53%) were male and 94 (47%) were female. Mean age of the patients was 49.9 ± 16.1 years. Michels Type 1 variation of proper hepatic artery, which represents the classical anatomic situation, was detected in 54% of the patients. The most frequent variations other than normal anatomy were Michels Type 5 variation (13%) and Michels Type 2 variation (11%). Unclassified variations were defined as Michels Type 11 variations and 5% of our patients were in this group. Covey Type 1 variation of hepatic portal vein was detected in 76% of our study group. The common variations other than Type 1 variations were Covey Type 2 variation (9%) and Covey Type 3 variation (8.5%). We detected that left hepatic vein and intermediate heptic vein unite and become a single vein and then join to inferior vena cava in 64% of our patients. Right hepatic vein, intermediate hepatic vein and left hepatic vein joined to inferior vena cava separately in 36% patients. Type A variation of the biliary ducts, which represents the classical anatomy according to Couinaud, was observed in 51.5% of our patients. Type C1 variation was detected in 15% and Type B variation was detected in 12% of our patients. To improve the success rate of surgical procedures and to prevent complications, anatomical knowledge of liver's vascular structures and bile ducts is essential. Our study demonstrates the vascular and biliar variations of liver in our study population. This knowledge of these variations should help surgeons in planning the surgical procedures.