Surgical anatomy of the right hepatic artery in Rouviere’s sulcus evaluated by preoperative multidetector-row CT images

BACKGROUND Lymph node dissection in Rouviere's sulcus (RS) is essential during left-sided hepatectomy and caudate lobectomy for hilar cholangiocarcinoma. However, the small segmental or subsegmental arteries (SA/SSA) are often encountered in RS and must be preserved to prevent critical complications, such as liver infarction or liver failure. The aim of this study is to elucidate the anatomy of SA/SSA around RS, which should be understood preoperatively. METHODS Between January 2008 and April 2013 from a total of 124 consecutive patients with hilar cholangiocarcinoma, preoperative multidetector-row computed tomography (MDCT) images were obtained at our institution and evaluated. The bifurcation patterns of the SA/SSA, the courses of the posterior SA/SSA and the bifurcation site of the SA/SSA were investigated using MDCT images. RESULTS The typical form, in which right hepatic artery (RHA) bifurcated into the anterior (Aant) and posterior (Apost) hepatic artery and thereafter, Aant/Apost bifurcated into the SA and SSA, was observed in 75 patients (60.5 %). On the other hand, the atypical forms, in which the SA/SSA were independently branched off from RHA before the main bifurcation of the Aant and Apost, were observed in 43 patients (34.7 %). The prior branched arteries supplied the whole or ventral area of segment VI (A6 or A6a) in 11 patients (8.9 %), which was most commonly observed in the atypical form. 15 patients (34.9 %) of the 43 patients with atypical form had partially supraportal posterior branches, that showed early-bifurcated posterior SA/SAA following supraportal course, while the other posterior SA/SSA followed infraportal course. The SA/SSA were extrahepatically bifurcated in 82 patients (66.1 %), comprised of all 43 atypical form and 39 of typical form, while the SA/SSA were intrahepatically bifurcated in remaining 36 patients of typical forms (29.0 %). CONCLUSION The extrahepatic bifurcation of the SA/SSA from RHA was relatively common. The early-bifurcated SA/SSA was often observed (34.7 % of total cohort) and, in 34.8 % of those atypical forms, posterior SA/SSA from RHA followed a supraportal course. The detailed preoperative knowledge of the anatomy, including SA/SSA, is crucial for left-sided hepatectomy for hilar cholangiocarcinoma.