Anatomic basis of vascular exclusion of the liver.

Segmental occlusive phlebography of the IVC, coupled with a slit in its posterior wall, injection of corrosive substances into the portal and hepatocaval network, biometry of the retrohepatic IVC and serial sections of injected livers from 64 subjects allowed a study of the anatomica aspects of VEL: the Pringle maneuver and clamping of the IVC above and below the hepatocaval connexion. Surgery for hepatic tumors close to the connexion can benefit from VEL but the right suprarenal and inferior phrenic veins must be clamped. Clamping of the suprahepatic IVC is dependent on the site at which the clamp is applied in relation to the diaphragm; an abdominal approach is possible in 79% of cases. The principal right hepatic vein, lacking a collateral over 1 cm external to the liver in one of every 2 cases, can be controlled outside the liver after mobilization of the lobe right of the liver, but caution is needed because of the predominance of "accessory" hepatic veins in 20% of cases. Control of the hepatic veins external to the liver on the left side is dangerous since a common trunk between the middle and left veins is frequent (84%). Collateral branches are also numerous and often vulnerable. Section of the left triangular ligament must be cautious. The relations between the hepatocaval connexion, diaphragm and right atrium also define modalities in the treatment of hepatic lesions such as membranes in the terminal IVC and the Budd-Chiari syndrome.