Branching patterns and drainage territories of the middle hepatic vein in computer-simulated right living-donor hepatectomies.

Full right hepatic grafts are most frequently used for adult-to-adult living donor liver transplantation (LDLT). One of the major problems is venous drainage of segments 5 and 8. Thus, this study was designed to provide information on venous drainage of right liver lobes for operation-planning. Fifty-six CT data sets from routine clinical imaging were evaluated retrospectively using a liver operation-planning system. We defined and analyzed venous drainage segments and the impact of anatomic variations of the middle hepatic vein (MHV) on venous outflow from segments 5 and 8. MHV variations led to significant shifts of segment 5 drainage between the middle and right hepatic vein. In cases with the most frequent MHV branching pattern (n = 33), a virtual hepatectomy closely right to the MHV intersected drainage vessels that provided drainage for 30% of the potential graft, not taking into account potential veno-venous shunts. In individuals with inferior MHV branches that extend far into segments 5 and 6 (n = 10), the overall graft volume at risk of impaired venous drainage increased by 5% (p < 0.001). If this is confirmed in clinical trials and correlated with intraoperative findings, the use of liver operation-planning systems would be beneficial to improve overall outcome after right lobe LDLT.