A Rare Variation of the Biliary Tree of Relevance to Live Liver Donation

Abstract

To the Editor: An appreciation of the potential anatomical variations of the vascular and biliary systems is essential for donor safety in the context of live donor hepatectomy (1, 2). We previously reported that variant biliary anatomy was present in a substantial proportion of donors with trifurcated portal veins (2, 3). The present report describes two rare cases of biliary anomaly with an independent bifurcation of a branch of segment 2 (B2) from the anterior or posterior bile duct. A 38-year-old male was admitted to our hospital to serve as a live donor for his sister, who had fulminant cryptogenic hepatic failure. Preoperative three-dimensional computed tomography (CT) of the donor did not demonstrate any anomalies of the portal vein, hepatic vein, or hepatic artery. Based on imaging and volume analysis of the liver, the donor underwent left hepatectomy with the caudate lobe. Intraoperative cholangiography demonstrated that B2 bifurcated independently from a branch of segment 7 (B7) (Figure 1A). Therefore, the left-lobe graft contained two bile duct orifices (B2 and B3). Intraoperative cholangiography confirmed that there was no bile leakage and that there was no biliary stenosis of the posterior branch. (A–C) Intraoperative cholangiography demonstrated that B2 independently bifurcated from B7 (case 1, A) or from the anterior branch (case 2, C). Magnetic resonance cholangiography demonstrated variant biliary anatomy, with B2 independently bifurcating from the anterior branch in case 2 (B). A 48-year-old male was admitted to our hospital to serve as a live donor for his wife, who had end-stage primary biliary cirrhosis. Preoperative three-dimensional CT of the donor demonstrated trifurcation of the portal vein, but there were no anomalies of the hepatic vein or hepatic artery. Magnetic resonance cholangiopancreatography (MRCP) demonstrated biliary anomaly with B2 bifurcating independently from an anterior branch (Figure 1B). Based on preoperative volume analysis, the left-lobe graft volume was considered to be too small for the recipient. Further, use of a right-lobe graft was complicated by the possibility that it possesses more than two bile duct orifices as well as two portal veins (anterior and posterior branches), which would increase the complexity of harvesting and of reconstruction. By contrast, the posterior segment graft had one bile duct orifice and portal vein with sufficient liver volume for the recipient. Therefore, the posterior segment graft was utilized for transplantation. The donor underwent posterior segmentectomy. Preoperative MRCP and intraoperative cholangiography demonstrated that B2 bifurcated from anterior branch (Figure 1C). The posterior segment graft had a single bile duct orifice and a single portal vein as well as a hepatic artery of the posterior branch and a right hepatic vein. Live donor liver transplantation requires careful graft selection to reduce the risk of complications. Biliary anomalies, which are sometimes associated with trifurcation of the portal vein, can complicate graft selection and donor surgery. This is the first report to describe independent B2 bifurcation from the anterior or posterior bile duct in a live donor. In donors with this anomaly, both the right and left-lobe grafts have multiple bile ducts. As illustrated in case 2 from the present report, the posterior graft represents a viable alternative for transplantation, provided graft volume is adequate. Preoperative evaluation of the biliary system has not been routinely utilized in our institution. Since dynamic CT may not detect important biliary variations, preoperative MRCP may be required to accurately characterize biliary anatomy, even in donor candidates without trifurcated portal veins. Based on the cost-benefit of this approach, we now routinely perform preoperative MRCP in all live donors in our institution. The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.