Cantlie's plane in major variations of the primary portal vein ramification at the porta hepatis: cutting experiment using cadaveric livers.

Major variations of the primary portal vein ramifications at the porta hepatis, such as trifurcation or an anterior sectorial trunk originating from the left portal vein (L+A pattern), seem to be relatively common morphologic features, with an incidence of 10% to 30%. However, it has not been clearly demonstrated whether the usual landmarks of Cantlie's line and the middle hepatic vein (MHV) are reliable indicators of the border between the right and left liver when these variations are present. We searched for any discrepancies between the actual left/right territorial border of the intrahepatic portal vein and the usual position of Cantlie's line or the MHV course using 30 fixed cadaveric livers with major variations including hilar trifurcation and the L+A pattern. In most livers (63.3%) the usual transection plane for left/right hepatectomy was occupied by Couinaud's segment VIII (S8), and the territory of the right portal vein extended to the left of Cantlie's plane. The MHV course did not correspond with the actual border between the right and left liver. Significant rightward shift of the MHV occurred in 76.9% of livers. The severity of the discrepancy seemed to depend on the distance between the origins of the anterior and posterior sectorial trunks along the main portal vein. In conclusion, variations of the primary portal ramifications alter the segmental configurations of the liver. Our results evoke doubt over the reliability of Cantlie's line and the MHV course as landmarks for major hepatectomy when such variations are present.