| Objective Classic liver transplantation, the most effective therapeutic option for children with end-stage liver disease, involves the interruption of portal venous flow. To further steady the hemodynami c and metabol i c status of reci pi ent, i n thi s experi mental study, the canine model was built to explore the feasibility and applicable value of a new method which was combined with temporary portocaval bridging and modified outflow reconstructed technique. Methods Healthy mongrel dogs were enrolled in donor group (25～30 kg, n=12) and recipient group (10-15 kg, n=12). Random pair was matched between donor and recipient animal. For donor operation, portal vein was clamped when left lateral lobe and left medial lobe were procured as a whole graft. For recipient operation, a temporary portacaval shunt was created with the jugular interposition graft in an end-to-side fashion, initiated when portal vein was clamped until the graft was revascularized. After a cross-clamp applied below the common trunk of the left and middle hepatic vein, an end-to-side anastomosis was performed between outflow orifice of the graft and anterolateral wall of recipient vena cava During operation, the changes of life signs, splanchnic organs, and blood gas index, serum biochemical parameter, pressure of portal vein were observed and recorded for every animal in both groups. By means of Doppler ultrasound measuring, the shunt flow volume at 15min after portal blocking was compared with normal portal venous flow volume for every recipient. Results Heart rate increase and blood pressure drop were noted soon after clamping of donor portal vein.5min afterwards, the portal venous pressure reached its peak level of (54.5±12.0) cmH2O rapidly (P＜0.01). At 30min after clamping, portal pressure still remained a relatively high level at (32.2±4.9) cmH20 (P＜0.01), and meanwhile severely congestion, edema and exudation generally occurred in splanchnic organs In recipient group, the prearrangement of temporary portacaval bridging allowed avoidance of the establishment of complex extracorporeal veno-venous bypass. All the grafts could be implanted successfully in recipient group, with no intraoperative death. The portal vein pressure slightly rose to (18.8±3.1) cmH2O 5min after portal occlusion (P=0.046), but returned to a normal level at 10min and kept to basal level till 30min (16.3cmH2O±2.3cmH2O, P=1.000). All visceral organs had been ruddy and elastic. The comparison between mean shunt flow volume (276.4±34.1) mL/min and normal portal venous flow (291.8±24.7) mL/min showed no statistically significant difference (P=0.219). Conclusion For piggy-back liver transplantation with partial liver graft, temporary portocaval bridging, combined with modified outflow reconstructed technique, can prevent splanchnic congestion and also preserve both portal and caval blood flows during anhepatic phase. This animal experimental study has justified the simplicity, safety and applicable value of this novel technique. Object To further increase the sources of limited liver grafts, the feasibility of a technique of liver transplantation was explored on an animal model of dog, using the middle hepatic lobe as an allograft. Methods 16 adult mongrel dogs were divided into donor group (n=12, weighed 20～25 kg) and recipient group (n=12, weighed 10～15kg). Random pair was matched between donor and recipient. For donor operation, the quadrate lobe and right middle lobe were separated by transection along parenchyma bridge. The medial sector graft was procured after in vivo perfusion, including the median hepatic vein, the middle branches of hepatic artery, portal vein and also hepatic duct. For recipient, a temporary portacaval shunt was created before hepatectomy. With piggyback technique, the outflow orifice of liver graft was anastomosed to the anterolateral wall of the recipient vena cava, below the common trunk of the left and median hepatic vein. The graft was revascularized via reconstructed hepatic vein and portal vein, and then hepatic artery and bile duct were anastomosed respectively in end-to-end manner. Biliary and abdominal drainage were inspected postoperatively. Autopsies were performed promptly after recipients'death, to investigate the possibility of technical complications. Results By prominent fissures, the canine liver was divided into 7 lobes, parenchyma bridges among which were thin. Located in medial sector, the quadrate lobe and the middle lobe were supported by middle branches of the portal vein and the proper hepatic artery, while the drainage was achieved through the median hepatic vein and the middle hepatic duct. The in situ splitting procedures could be completed in all donors, with no warm ischemic damage to partial grafts. The mean operative duration was (215.0±67.7) min and bleeding volume was (229.3±66.5) mL. GRWR of medial sector graft (1.3±0.3)%differed significantly (P<0.01) from GRWR of left sector liver (2.1±0.4)%and right sector graft (0.9±0.1)%. The operation on recipient resulted in mean operative time of (327.6±75.3) min, blood loss of (415.5±79.8) mL and anhepatic time of (33.6±7.5) min.12 grafts were successfully implanted, while bile secretion was observed (8.3±3.6)min after portal reperfusion. Median survival duration was 92.5 (18～272) h, but surgical complications were not found at autopsy. Conclusion Medial sector split liver transplantation can be performed on canine model, potentially providing a reliable expansion of organ supply. Object To ultimately maximize donor organ use, the strategy of tripartition of a whole deceased liver graft for use in 3 recipients was explored on an animal model of dog. Methods Adult healthy mongrel dogs were selected to be donors (n=30, weighed 20～25 kg) and recipients (n=30, weighed 8-15kg). Random pair was matched between donor and recipient. For donor operation, between the right lateral lobe and right middle lobe, the left middle lobe and the quadrate lobe were separated by transection along parenchyma bridge. After in vivo perfusion, the left, the middle and the right sector liver graft were procured, pri mary branches of which were divided neare to main stem. Among three liver grafts, the one was chosen to be implanted if it's GRWR>1.0% and most fitting 1.5%. Group A included recipients which if left sector graft was chosen. All recipients entered Group B when middle sector grafts were to be implanted into. And Group C consisted of those recipients recieved right sector grafts. With piggyback technique, the outflow orifice of liver graft was anastomosed to the anterolateral wall of the recipient vena cava The graft was revascularized via reconstructed hepatic vein and portal vein, and then hepatic artery and bile duct were anastomosed respectively in end-to-end manner. Biliary and abdominal drainage were inspected postoperatively. Autopsies were performed promptly after recipients' death, to investigate the possibility of technical complications. Results By prominent fissures, the canine liver was divided into 7 lobes, parenchyma bridges among which were thin. The bridge of parenchyma connecting the right lateral lobe to the right middle lobe was much thinner than that connecting the left middle lobe to the quadrate lobe. No major conduit was found during transection of these two parenchyma bridges. The portal vein was split into three branches. The common bile duct was formed from the union of three hepatic ducts, the left, the middle and the right hepatic duct. The hepatic vein was consist of the left, the median and the right hepatic vein. Anatomical variations of hepatic artery could be found. Among three recipient groups, the comparasion of operation time, anhepatic time and blood loss did not show significant differences (P>0.05), but the mean recipient weight liver graft weight and GRWR differed significantly (P<0.01). In 3 groups, none of the recipients died during surgery, once the hepatic vein and the portal vein were anastomosed and declamped, the implanted liver regained its color soon. Its appearance returned to normal following arterial revascularization. There was no statistical difference at survival duration among 3 groups (128.3h±48.5h vs.102.7h±59.8h vs. 98.7h±46.8h,P=0.234). Ascites and liver necrosis was not found at autopsy. Bile was present in the bile duct and all anastomoses were patent. Conclusion The experimental results indicate that the whole liver of a big dog can be split into three parts, every one of which can be transplanted to a small recipient as an independent allograft.
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