Great progress has been made in the field of liver transplantation (LT) over the past two decades. This progress brings up the shortage of organs for patients in need of LT. Split liver transplantation (SLT) was developed in the late of 1980s by Pichlmayr et al as methods to increase donor organ. Early SLT experiences resulted in poor outcomes. According to the European Liver Transplant Registry between 1968 and 2000, SLT represented 3.7% of the total grafts. In the 2000s, the volume of SLT increased up to 6%. Further understanding of intrahepatic anatomy, improvement of surgical techniques, and well-established donor and recipient selection criteria for SLT have made SLT more popular. On the contrary, SLT comprised less than 1% of all LTs between 2002 and 2009 in the United States, although it has been estimated that approximately 20% of all deceased donors meet the United Network for Organ Sharing (UNOS) guidelines for split liver.
There are two methods to split the liver: in situ and ex situ technique. In-situ technique can decrease the cold ischemic time by eliminating the graft division procedure in bench operation, prevent the incidence of bile leak, and facilitate complete hemostasis of the cut surface. However, in situ technique is often time-consuming, needs the cooperation with other graft harvesting teams, and may increase blood loss and volume replacement.
Conventional SLT means dividing the deceased donor liver into the left lateral section for a pediatric recipient and the right trisection graft for an adult recipient. Most SLTs have been performed as the conventional types. SLT has resulted in a reduction of waiting list mortality for pediatric population who are disadvantaged due to lack of size-matched donors and reduces the pressure on parents to become live donors. According to the recent study from UK, the development of an ‘‘intention to split policy’’ to obtain 2 suitable grafts from any donor that matched the inclusion criteria lead to a significant increase of SLT than before. SLT satisfied more than 65% of the needs of our pediatric waiting. Especially, there were no deaths on the pediatric wait list over the last 4 years.
Splitting one liver into two grafts for two adult recipients was theoretically more attractive to expand the donor pool for adult patients. SLT for two adult recipients requires full right-liver and full left-liver grafts. However, adult recipient requires sufficient graft volume to satisfy metabolic demand. Small-sized graft volume for adult recipients resulted in increased incidence of primary non-function (PNF) or small-for-size (SFS) graft syndrome. Splitting of the liver in a deceased donor for two adults is only recommended in highly selected situations. Proper donor selection is the first step for successful SLT for two adults. The criteria for splitting liver in a deceased donor include young age, low BMI, stable hemodynamic status with minimal inotropic agent, normal liver function, and short hospitalization before donation. To acquire good results after SLT for two adults, we need proper donor and recipient selection and experienced surgical techniques. In-situ SLT for two adults is a feasible option to expand the door pools in selected situations.
The following factors such as changes in recipient and donor selection and matching, changes in allocation policy, and improved technical proficiency have influenced outcomes. The risk of graft failure is now similar between split and whole-liver recipients. SLT, which is based on unique ability of the liver to regenerate, is an excellent idea to increase the donor grafts. Through the expansion of SLT, the transplant community might be able to both increase the organ pool and bridge the liver demand-supply gap.