Variations in anatomy of the middle hepatic vein and their impact on formal right hepatectomy

Background: We evaluated the incidence of variations of the middle hepatic vein (MHV) branches and their impact on formal right hepatectomy for living-donor liver transplantation. Methods: Fifty consecutive patients who underwent hepatic multidetector row computed tomography (CT) were evaluated. Three-dimensional volume rendering techniques were used to evaluate the different branching patterns of the MHV. An incision plane was constructed to simulate a formal hepatectomy along Cantlie's line, immediately to the right of the MHV. The number of transected vessels was recorded by consensus of two observers. Results: In 11 patients (22%) the MHV had no major (>5 mm) branches. In 15 patients (30%) a major branch was seen draining the right lobe, and in 10 patients (20%) a major branch was seen draining each lobe. In five patients (10%) two major branches were seen draining the right lobe and a single branch draining the left lobe. The remaining nine patients (18%) had other variations, including one patient (2%) with the right hepatic vein arising from the MHV. A formal hepatectomy along Cantlie's line was truly avascular in 15 patients (30%). Conclusion: A formal right hepatectomy can be performed without transecting major branches of the MHV in one-third of patients. In the remaining two-thirds, one or more major branch of the MHV will need be transected. Preoperative knowledge of these variations is critical for surgical planning.