The Experimental Study On Radiofrequency Ablation Via The Lumen Of Bile Duct In Hilum Hepatis

BACKGROUND: The prognosis of patients with hilar cholangiocarcinoma is still unsatisfactory. The general resection rate is less than 40%. The survival rate of 1-, 3-, 5-year after resection is about 80%, 50% and 40% respectively. The survival rate of 1-, 3-, 5-year after OLT was just 60%, 40% and 30% respectively. More than 60% of the patients with hilar cholangiocarcinoma have to accept palliatively internal or external biliary drainage to relive jaundice. Surgical biliary drainage is one of the main methods for palliative management of hilar cholangiocarcinoma. One of the options of surgical biliary drainage is transtumoural tube placement into biliary tract. Radiofrequency ablation (RFA) has been used for treatment of many kinds of unresectable tumors because of the advantages such as simple operation, mini-trauma, less complications and repeatable administration. However, no report on RFA via the lumen of bile duct has been yet found for treatment of hilar cholangiocarcinoma. If RFA via the lumen of bile duct could be performed for treatment of hilar cholangiocarcinoma before transtumoural tube placement into biliary tract, it would be beneficial to the patients with unresectable hilar cholangiocarcinoma.The aim of the study was to afford clinical evidence for treatment of unresectable hilar cholangiocarcinoma with RFA via the lumen of bile duct in hilum hepatis through both in vitro and in vivo experimental researches.PARTⅠ: An in vitro Experimental Study on Pathological Changes of Bile Duct and Hepatic Tissue after Radiofrequency Ablation via the Lumen of Bile Duct in Hilum HepatisOBJECTIVES: To observe the pathological changes of bile duct and hepatic tissue after RFA via the lumen of bile duct in hilum hepatis and to investigate the sizes of coagulation zones corresponding to the length of non-insulated mono-electrode, the power output and the ablation duration in vitro.MATERIALS AND METHODS RFA by inserting the non-insulated mono-electrode into the lumen of bile duct in hilum hepatis were performed in 48 bile duct targets, which were divided into 4 groups averagely according to the length of non-insulated mono-electrode, the power output and the ablation duration, from 20 fresh isolated porcine livers. The sizes of coagulation zones in section were detected and the pathological changes of bile duct and adjacent hepatic tissue were observed under microscope.RESULTS Semi-oval gray-white coagulation zones in section were observed, with long axes along bile duct and short axes along the wall of bile duct with adjacent hepatic tissue. The wall of bile duct was complete. Necrosis of mucosal and submucosal layers of bile duct and denaturation of hepatic tissue were observed under microscope. On 13-mm non-insulated mono-electrode and 5-W power output, when the ablation duration was 2mins, 4mins respectively, the long axial mean diameters of coagulation zones were (16.92±1.62)mm, (16.83±1.90)mm respectively, with no statistical difference(P>0.05), and the short axial mean diameters were (4.08±0.67)mm, (6.50±1.08)mm respectively, with statistical difference(P<0.05); On 13-mm non-insulated mono-electrode and 2-min ablation duration, when the power output was 5W, 10W respectively, the long axial mean diameters were (16.92±1.62)mm, (16.08±1.62)mm respectively, with no statistical difference(P>0.05), and the short axial mean diameters were (4.08±0.67)mm, (6.08±1.24)mm respectively, with statistical difference(P<0.05); On 5-W power output and 4-min ablation duration, when the length of non-insulated mono-electrode was 13mm, 9mm respectively, the long axial mean diameters were (16.83±1.90)mm, (13.25±1.14)mm respectively, with statistical difference(P<0.05), and the short axial mean diameters were (6.50±1.08)mm, (6.17±1.19)mm respectively, with no statistical difference(P>0.05).CONCLUSIONS Coagulation zone can be produced with RFA via the lumen of bile duct in hilum hepatis. The long axial diameter of coagulation zone is related to the length of non-insulated mono-electrode and the short axial diameter is related to the power output or the ablation duration. PARTⅡ: An in vivo Experimental Study on Effect of the Pringle Manoeuvre on Radiofrequency Ablation via the Lumen of Bile Duct in Hilum HepatisOBJECTIVES To observe whether coagulation zones can be produced with RFA via the lumen of bile duct in hilum hepatis in vivo and to investigate the effect of blood flow in hilum hepatis on the sizes of coagulation zones.MATERIALS AND METHODS Fourteen bile duct targets in hilum hepatis, which were grouped randomly into the non-Pringle manoeuvre group and the Pringle manoeuvre group with 7 bile duct targets each groups, were chosen under general aneasthesia through laparotomy in 6 healthy domestic pigs. RFA by inserting the 13-mm non-insulated mono-electrode into the lumen of bile duct was performed on 5-W power output and 4-min ablation duration. The pathological changes of bile duct and adjacent hepatic tissue in bile duct targets were observed macroscopically and microscopically. The sizes of coagulation zones in section were detected.RESULTS Semi-oval gray-white coagulation zones in section were observed in both groups. There were obviously dark-red rims surrounding coagulation zones in both groups. Necrosis of mucosal and submucosal layers of bile duct and denaturation of adjacent hepatic tissue in coagulation zones were found under microscope. Hemorrhage of hepatic tissue was found in dark-red rims under microscope. The long axial mean diameters in the non-Pringle manoeuvre group and in the Pringle manoeuvre group were (13.29±1.38)mm, (13.29±1.11)mm , respectively, with no statistical difference(P>0.05). The short axial mean diameters in the non-Pringle manoeuvre group and in the Pringle manoeuvre group were (3.14±1.07)mm, (4.57±0.98)mm, respectively, with statistical difference(P<0.05).CONCLUSIONS The typical ablation zone can be produced with RFA via the lumen of bile duct in hilum hepatis in vivo. The blood flow in hilum hepatis affects the short axial diameter of coagulation zone but does not affect the long axial diameter. With or without the Pringle manoeuvre, the long axial diameter is coincident with the length of non-insulated mono-electrode. PARTⅢ: An in vivo Experimental Observation on the Complications concerning Radiofrequency Ablation via the Lumen of Bile Duct in Hilum HepatisOBJECTIVES To observe the complications concerning RFA after RFA via the lumen of bile duct in hilum hepatis and the pathological progress of the tissue in ablation zones.MATERIALS AND METHODS Fourteen healthy dogs were divided randomly into 2 groups with 7 dogs each groups. One or two bile duct targets in hilum hepatis in each dogs were chosen through laparotomy under general anesthesia. RFA by inserting a 13-mm non-insulated mono-electrode into the lumen of bile duct was performed on 10-W power output, 4-min ablation duration in groupⅠand on 5-W power output, 8-min ablation duration in groupⅡ. After RFA, 2 dogs were sacrificed in 3 days and 1 dog in 9 days and 4 dogs in 14 days respectively in each groupes. The complications concerning RFA such as bile leakage, cholelithiasis, hepatic artery thrombosis, portal vein thrombosis, hepatic vein thrombosis and vena cava thrombosis were observed. RESULTS Portal vein thrombosis, hepatic vein thrombosis and vena cava thrombosis occurred in one dog. Cholelithisis occurred in one dog. No hepatic artery thrombosis occurred in all dogs. No bile leakage caused by RFA occurred in all dogs. Obvious necrosis of the mucosal and submucosal layers of the wall of bile duct and hepatic tissue in coagulation zones occurred in 3 days after RFA. The infiltration of inflammatory cells and partial fibrosis of the mucosal and submucosal layers of bile duct and hepatic tissue occurred in 9 days after RFA. Obvious fibrosis of the wall of bile duct and hepatic tissue occurred in 14 days after RFA.CONCLUSIONS The complications caused by RFA occur seldom after RFA via the lumen of bile duct occur seldom. The necrosis, the infiltration of inflammatory cells and gradual fibrosis of the mucosal and submucosal layers of bile duct and hepatic tissue occur in ablation zone.