| Objective To clarify the variations of biliary confluence pattern and discuss their surgicopathologic implications for Bismuth-Corlette(BC)type IV hilar cholangiocarcinoma applied to hemihepatectomy.Methods The clinicopathological data of 79 patients with advanced hilar cholangiocarcinoma who underwent laparotomy at our institution from January 2014 to August 2016 were retrospectively collected.Concomitant precise hemihepatectomy was the standard approach.The imaging data of 97 patients with distal bile duct obstruction who underwent multi-detector computed tomography during the same period,were collected and converted to three-dimensional reconstruction for anatomic study of bile ducts.Normal biliary confluence pattern was defined as the peripheral segment IV duct(B4)joining the common trunk of segment II(B2)and segment III(B3)ducts to form the left hepatic duct(LHD)that then joined the right hepatic duct(RHD)to form the common hepatic duct.The lengths of bile ducts were measured,including LHD,RHD and the lengths from left and right secondary biliary ramifications to the right side of the umbilical portion of the left portal vein(Rl-L)and the cranio-ventral side of the right portal vein(Rr-R)respectively.Comparisons of bile duct lengths in different configurations,resectable bile duct length and surgicopathologic findings in different BC types were conducted.Results Anatomic study of bile ducts consisting of 97 patients showed three distinct ramification patterns of left biliary system.Normal configuration(type I)was seen in 67 patients(69.1%)while variant anatomy could be classified into two types:typeⅡ—B4 joining the common trunk of B2 and B3 at a point close to the hepatic hilum,and type Ⅲ-B2 joining the common trunk of B3 and B4,which were found in 16(16.5%)and 14(14.4%)patients,respectively.LHD was significantly longer in type Ⅰ(19.6±4.9mm)than in type Ⅱ(9.3 ± 2.5mm)and type Ⅲ(7.7 ± 2.1mm)variation.Conversely,the length of Rl-L was significantly longer in type Ⅱ(20.1 ± 3.9mm)and type Ⅲ(20.0 ± 3.1mm)variation than in typeⅠ(10.3±3.4mm).RHD was absent in 22 patients(22.7%)and the length of Rr-R was significantly longer in absent cases than cases with RHD(16.4 ± 2.6 and 8.2 ± 2.5 mm,respectively,p<0.001).Of 79 patients with advanced hilar cholangiocarcinoma who underwent laparotomy,14 patients were unresectable while 62 patients had R0 resection and 3 patients had R1 resection.In the R0 resection group,the resectable bile duct length for BC type Ⅳa tumors(17.4 ± 1.8mm)was significantly longer than the R1-L length in normal configuration(p<0.001),and type Ⅲ variation was the predominant pattern.The resectable length for BC type IVb tumors(15.2 ± 2.5mm)was marginally shorter than that in BC typeⅢb tumors(16.7 ± 1.5mm,p=0.085)and comparable with the Rr-R length in RHD absent cases(16.4 ± 2.6mm,p=0.177),but significantly longer than the Rr-R length in normal configuration(p<0.001).The estimated length was 8.5 ± 2.0 mm in unresectable cases.Clinicopathologic analysis demonstrated that there was no significant difference between BC type Ⅲ and Ⅳ tumors,except for the rate of nodal metastasis(29.7%and 76.0%,respectively,p<0.001).Conclusion Concomitant hemihepatectomy might be selected for curative-intent resection of BC type Ⅳ tumors considering the advantageous biliary variations,including B4 draining into B3,B4 joining the common trunk close to hilar confluence and the absence of RHD.Anatomical trisegmentectomy or liver transplantation is recommended for the resectable bile duct length less than 10mm.Biliary variations might result in excessive classification of BC type Ⅳ but requires validation on further study. |
PDF Full Text Request