A New Approach For Precise Segmental Hepatectomy:Intra-operative Ultrasound Guided Infusion Of A New Thermosensitive Gel Into Portal Vein Branch

Object:Segmental or subsegmental hepatectomy (SH) is considered the gold standard approach for liver resection in patients with hepatocellular carcinoma (HCC). The SH methods available up to now were rather complex and for that reason of limited use. Herein a new technique for demarcation of the resection area by means of intraoperative ultrasound (IOUS)-guided infusion of a novel gel into feeding portal vein was described, and the feasibility, efficacy and safety of the new technique were detected.Methods:Poloxamer407(P407) solution of different concentration mixed with indocyanine green(ICG) were developed, which stay liquid at room temperature and changed into firm gel the moment approach to body temperature. The gelation temperature and occlusion effect of the solutions were firstly detected in rats. In the feasibility and efficacy study,6pigs (SH-A group) underwent IOUS-guided infusion of P407-ICG solution to accomplish SH,6pigs (SH-B group) underwent IOUS-guided infusion of ICG to accomplish SH, and another 6 pigs underwent partial hepatectomy(PH group). Operation time, bleeding loss, laboratory blood test and post-operative morbidity of animals were recorded. All of the animals were reopened again 7th day to evaluate the resident liver, and heart, lung, kiddy were acquired for pathology. In the safety study, the outcome of infusion the mixture solution into hepatic vein, biliary tract and liver parenchyma was studied.Results:The P407-ICG solution (concentration of 18%) gelated immediately at 26℃ and it could occlude the rats’portal vein firmly for about 12minites. All of the animals in SH-A group and PH group finished the planned surgery successfully, and 2 pigs of the SH-B group didn’t dye correctly resulting unsuccessful segmental hepatectomy. Compared with PH group, the operation time of SH group was longer, but the bleeding volume during operation was significantly less, while there were no differences between the two subgroups of SH. (Operation time:SH-A group:118.5± 10.2min, SH-B group:120.8±7.4min, PH group:98.0±8.9min; Bleeding volume: SH-A group:83.3±14.0ml, SH-B group:86.7±12.9ml, PH group:139.2±18.5ml) Laboratory blood tests of the 3 groups had no differences, which were back to normal within one week after surgery. The dissolution time of the gel in hepatic veins and biliary tract were 10.5±1.1min and 14.1±1.5min. Also, the gel infused into liver parenchyma was found dissolved completely in second operation on 3rd day, and no morbidity or mortality was recorded postoperatively. There no micro or macroscopic change of organs in pathology.Conclusions:Demarcation the liver segment to be resected by IOUS-guided infusion of P407-ICG solution to feeding portal vein is feasible and effective, which is more likely to succeed compared to IOUS-guided infusion of ICG. Moreover, it didn’t result any problem even if infused in liver parenchyma, biliary tract or hepatic veins.