Objective: We present our experiences with infraportal bile duct of the caudate lobe (B1) and discuss surgical implications of this rare variation.
Summary background data: Although various authors have investigated biliary anatomy at the hepatic hilum, an infraportal B1 (joining the hepatic duct caudally to the transverse portion of the left portal vein) has not been reported.
Methods: Between January 1981 and December 2005, 334 patients underwent hepatectomy combined with caudate lobectomy for perihilar cholangiocarcinoma. Four of them (1.2%) had infraportal B1 and were investigated clinicoanatomically.
Results: All infraportal B1 were B1l, draining Spiegel's lobe; no infraportal B1r (draining the paracaval portion) or B1c ducts (draining the caudate process) were found. The infraportal B1l joined the common hepatic duct or the left hepatic duct. Three patients underwent right trisectionectomy with caudate lobectomy; for one, in whom preoperative diagnosis was possible, combined portal vein resection and reconstruction were performed before caudate lobectomy to resect the caudate lobe en bloc without division of infraportal B1. For the other 2 patients, the infraportal B1 was divided to preserve the portal vein, and then the caudate lobe was resected en bloc. The fourth patient underwent right hepatectomy with right caudate lobectomy; the cut end of the infraportal B1 showed no cancer by frozen section, so the bile duct was ligated and divided to preserve the left caudate lobe.
Conclusion: Infraportal B1 can cause difficulties in performing right-sided hepatectomy with caudate lobectomy or harvesting the left side of the liver with the left caudate lobe for transplantation. Hepatobiliary and transplant surgeons should carefully evaluate biliary anatomy at the hepatic hilum, keeping this variation in mind.