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 Cantie'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 Candie'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.