How Should We Treat Short Hepatic Veins and Paracaval Branches in Anterior Hepatectomy Using the Hanging Maneuver Without Mobilization of the Liver? An Anatomical and Experimental Study

This study investigates the relevant anatomy for applying the hanging maneuver to hepatectomy by an anterior approach, where liver mobilization is not possible. Using 176 cadaveric livers, we morphometrically investigated the distribution of venous openings within the retrohepatic portion of the inferior vena cava (IVC); next, we conducted a series of experiments to identify which course for insertion of a pair of forceps preserved the thickest of these veins. After anterior dissection of the liver, we carried out an anterior incision along a plane within an area free of venous openings in the IVC. The area free of venous openings was between the thickest caudate vein and the inferior right hepatic vein (IRHV), and averaged 16.2 mm in width. When forceps were inserted along the rightward course connecting the right inferior angle of the right lobe and the same pocket-like space between the terminals of the middle and right hepatic veins, the caudate vein was very likely to be preserved, whereas the IRHV was not. In contrast, the leftward course connecting the gallbladder fossa and the pocket-like space provided an almost opposite incidence of damage. The portal territory of the hilar bifurcation was most likely to be damaged during a virtual incision along an avascular plane; however, the caudate branch of left portal origin was rarely damaged. The rightward course may be the best method for forceps insertion in cases where there is no IRHV. To preserve the caudate vein and the IRHV, taping on the right side of the IRHV and retracting to the right, or changing the direction of the forceps from leftward to rightward when the tip of the forceps is anterior to the IVC is recommended. The hanging maneuver by an anterior approach without mobilization is convenient for right or left hepatectomy for large tumors or hardened liver.