Split liver transplantation in adults

Abstract

Split liver transplantation (SLT), while widely accepted in pediatrics, remains underutilized in adults. Advancements in surgical techniques and donor-recipient matching, however, have allowed expansion of SLT from utilization of the right trisegment graft to now include use of the hemiliver graft as well. Despite less favorable outcomes in the early experience, better outcomes have been reported by experienced centers and have further validated the feasibility of SLT. Importantly, more than two decades of experience have identified key requirements for successful SLT in adults. When these requirements are met, SLT can achieve outcomes equivalent to those achieved with other types of liver transplantation for adults. However, substantial challenges, such as surgical techniques, logistics, and ethics, persist as ongoing barriers to further expansion of this highly complex procedure. This review outlines the current state of SLT in adults, focusing on donor and recipient selection based on physiology, surgical techniques, surgical outcomes, and ethical issues.

Keywords: Adults; Donor and recipient selection; Ethical issues; Graft size; Graft survival; Split liver transplantation; Surgical technique.

Figure 1

Graft types for split liver transplantation. The most common type is the left lateral segment graft (segment II and III) for children and the right trisegment graft (segment I, IV-VIII) for adults. In hemiliver splitting, the liver is split on the right side of the middle hepatic vein to yield the left hemiliver graft (segment I-IV) and the right hemiliver graft (segment V-VIII) for 2 adults or adult-sized recipients.

Figure 2

Single venous outflow of the left hemiliver graft. A large common channel of the left and middle hepatic veins is seen.

Figure 3

Left hemiliver graft with the celiac trunk (arrow). In this hemiliver split, the celiac trunk was retained with the left lobe graft and the remaining structures including the vena cava, main portal vein, and common hepatic duct were retained with the right lobe graft as described by Bismuth[3].

Figure 4

Right hemiliver graft with new middle hepatic vein. Implantation was performed using the conventional caval interposition technique. Two arrowheads indicate caval anastomoses. To prevent venous congestion in the anterior segment, an iliac vein graft was used to create new middle hepatic vein that is anastomosed to the orifice of the left and middle hepatic veins on the graft vena cava (arrow). From Hashimoto et al[10].

Figure 5

Distributions of graft-to-recipient weight ratio in recipients who received hemiliver grafts at Cleveland Clinic. With ideal graft-recipient matching, the majority of recipients achieved a graft-to-recipient weight ratio (GRWR) > 1.0%. More importantly, hemiliver grafts with low GRWR were avoided in recipients with severe portal hypertension in order to prevent small-for-size related graft failure. A line within the box indicating the mean and the lower and higher boundaries of the box indicating the 25^th and 75^th percentile, respectively. Whiskers below and above the box indicate the 10^th and 90^th percentiles. From Hashimoto et al[10].