Large inferior right hepatic vein. Clinical implications

The right middle and inferior hepatic vv. are very frequent, indeed constant, but usually of small caliber. The presence of an extra-wide right inferior hepatic v., usually solitary, produces a variation in the venous drainage of the right lobe of the liver. The right inferior hepatic vv. reaching or exceeding a caliber of 0.5 cm were investigated in 125 anatomic liver specimens: 70 injection-corrosion specimens, 32 formolised livers and frontal or frontal-oblique sections of the trunk made in 23 cadavers. The incidence of such vv. was estimated at 9% in the injection-corrosion specimens, 13% in the sections and 16% in the formolised livers. The incidence of these vv. in the literature varies from 10% to 24% according to the method used to demonstrate them. Usually, there is a balance between the right superior and inferior hepatic vv. Rarely, the right inferior hepatic v. predominates compared with the right superior hepatic v. The position of an extra-wide right inferior hepatic v. is constant, close to the visceral aspect of the liver. Its appropriate territory is segment VI, but it may encroach somewhat on adjacent segments. Clinically, the existence of an extrawide right inferior hepatic v. as detected by MRI and, especially, located by intraoperative ultrasonography, allows performance of a subtotal hepatectomy leaving only segment VI. In certain pathologic conditions, thanks to the development of anastomoses between the hepatic vv., an extra-wide right inferior hepatic v. may contribute to a compensatory circulation towards the right atrium.