Objective: To investigate the feasibility of liver transplantation using the independent medial split liver graft, so as to broaden the sources of donor liver.
Methods: Healthy adult mongrel dogs were divided into donor group (n=12, 20-25 kg) and recipient group (n=12, 10-15 kg), and each of the donors was then randomly paired with a recipient. In the donor operation, the middle part of the liver (quadrate lobe and right medial lobe) was splitted in vivo, and then along with the medial portal branch, middle hepatic artery and hepatic duct, the independent medial split liver graft was procured and weighed after in situ perfusion. In the recipient operation, a temporary portacaval shunt was created before hepatectomy; implantation was done by piggyback technique, whereby the outflow orifice of the graft was anastomosed to the anterior wall of the recipient vena cava in an end-to-side manner, and the blood flow of the transplanted liver was restored by an end-to-end anastomosis of the donor medial portal branch and the main trunk of the recipient portal vein, and finally the reconstruction of the hepatic artery and biliary duct was performed. The biliary tract and abdominal drainage were detected daily after operation. After recipient's death, autopsy was done and pathological examination of the graft specimen was performed.
Results: The canine liver was divided by deep fissures into seven lobes, which are connected by meager parenchymal bridges. The quadrate lobe and right medial lobe are supplied by the medial portal branches and middle hepatic artery, and their blood is returned via the middle hepatic vein; biliary drainage is by the middle hepatic duct. In the donor group, the in situ splitting procedures were all accomplished, and the average operative duration was (215.0±67.7) min and bleeding volume was (229.3±66.5) mL. The graft-recipient weight ratio (GRWR) of middle part liver graft [(1.3±0.3) %] was significantly different (P<0.01) from that of the presumed left part graft [(2.1±0.4) %] and right part graft [(0.9±0.1) %] (both P<0.01). In the recipient group, the mean operative time was (327.6±75.3) min, blood loss was (415.5±79.8) mL and anhepatic time was (33.6±7.5) min. All the 12 grafts were successfully implanted, the cold ischemia time was (41.9±12.1) min, and the bile secretion was observed at (8.3±3.6) min after portal reperfusion. The parameters of liver function of the recipients were changed on the first day after surgery and then gradually returned to normal. The median survival time of the recipients was 92.5 (18-272) h, and no case died from surgical procedure complications such as anastomotic bleeding and thrombosis.
Conclusion: This canine model proves that the central part of the liver can be splitted as a graft separately, and it may provide an alternative idea for expanding the sources of donor liver.