Split liver transplantation (SLT) from deceased donors is a potential solution to the global organ shortage. While effective in patients with mild disease, outcomes in high MELD score recipients remain uncertain and conflicting. This study compares survival in high vs. low MELD score recipients.

This retrospective single-centre study included all consecutive patients transplanted with a split liver graft between 2010 and 2022. Two groups of recipients with MELD<25 and ≥ 25 at LT were compared.

The study population included 119 patients (n = 98 with MELD<25, n = 21 with MELD≥25) with an average follow-up of 55 months. Both groups were comparable in terms of indication for transplantation and donor characteristics. The high MELD group required more blood transfusions (7 vs. 3 units; p < 0.001) during LT and had a longer stay in intensive care unit (7 vs. 5 days; p = 0.011). Biliary, arterial, and venous complications were similar between groups, as well as graft survival (5 years: 75 % vs. 61 %, p = 0.35) and long-term overall survival (5 years: 83 % vs. 75 %, p = 0.17).

Our results indicate that SLT for patients with MELD≥25 improves access to grafts, is feasible and safe, without significant increased risk of severe complications or decreased long-term overall patient or graft survivals.

Recent advances in machine perfusion have revolutionised the field of transplantation by prolonging preservation, permitting evaluation of viability prior to implant and rescue of discarded organs. Long-term perfusion for days-to-weeks provides time to modify these organs prior to transplantation. By using long-term normothermic machine perfusion to facilitate liver splitting and subsequent perfusion of both partial organs, possibilities even outside the clinical arena become possible. This model remains in its infancy but in the future, could allow for detailed study of liver injury and regeneration, and ex-situ treatment strategies such as defatting, genetic modulation and stem-cell therapies. Here we provide insight into this new model for research and highlight its great potential and current limitations.

Given the current organ shortage crisis, split liver transplantation (SLT) has emerged as a promising alternative for select end-stage liver disease patients.

To introduce an ex-vivo liver graft splitting approach and evaluate its safety and feasibility in SLT.

A retrospective analysis was conducted on the liver transplantation data from cases performed at our center between April 1, 2022, and May 31, 2023. The study included 25 SLT cases and 81 whole liver transplantation (WLT) cases. Total ex-vivo liver splitting was employed for SLT graft procurement in three steps. Patient outcomes were determined, including liver function parameters, postoperative complications, and perioperative mortality. Group comparisons for categorical variables were performed using the χ²-test.

In the study, postoperative complications in the 25 SLT cases included hepatic artery thrombosis (n = 1) and pulmonary infections (n = 3), with no perioperative mortality. In contrast, among the 81 patients who underwent WLT, complications included perioperative mortality (n = 1), postoperative pulmonary infections (n = 8), abdominal infection (n = 1), hepatic artery thromboses (n = 3), portal vein thrombosis (n = 1), and intra-abdominal bleeding (n = 5). Comparative analysis demonstrated significant differences in alanine aminotransferase (176.0 vs 73.5, P = 0.000) and aspartate aminotransferase (AST) (42.0 vs 29.0, P = 0.004) at 1 wk postoperatively, and in total bilirubin (11.8 vs 20.8, P = 0.003) and AST (41.5 vs 26.0, P = 0.014) at 2 wk postoperatively. However, the overall incidence of complications was comparable between the two groups (P > 0.05).

Our findings suggest that the total ex-vivo liver graft splitting technique is a safe and feasible approach, especially under the expertise of an experienced transplant center. The approach developed by our center can serve as a valuable reference for other transplantation centers.

Split-liver transplantation offers a solution to the organ shortage problem. However, the outcomes of extended right lobe liver transplantation (ERLT) and whether it is a suitable alternative to full-size liver transplantation (FSLT) remain controversial. We compared the outcomes of ERLT and FSLT in adult recipients of 43,409 first deceased donor liver transplantations using Cox regression. We also analyzed 612 ERLT and 1224 FSLT 1:2 matched cases to identify factors that affect ERLT outcome. The risk of graft loss was significantly higher following ERLT than following FSLT during the first posttransplantation year in the matched and unmatched collective (hazard ratio [HR], 1.39 and 1.27 and P = 0.01 and 0.006, respectively). Every additional hour of cold ischemia time (CIT) increased the risk of 1-year graft loss by 10% in the ERLT group compared with only 3% in the FSLT group (P = 0.003 and <0.001, respectively). Importantly, the outcome of ERLT and FSLT did not differ significantly if the CIT was below 10 hours (HR, 0.71; P = 0.22). One-year graft and patient survival were lower in high-risk ERLT recipients with a Model for End-Stage Liver Disease (MELD) score of ≥20 (HR, 1.88; P = 0.03 and HR, 2.03; P = 0.02). In the male recipient-male donor combination, ERLT recipients had a higher risk of 1-year graft loss than FSLT recipients (HR, 2.44; P = 0.006). This was probably because of the significantly higher MELD score in ERLT recipients (P = 0.004). ERLT in adults is an adequate alternative to FSLT and offers an elegant solution to the problem of organ shortage as long as the cold storage is less than 10 hours and the recipient's MELD score is <20.

Split liver transplantation addresses donor shortages by facilitating the transplant of two recipients using one donor liver. Some still consider these grafts inferior due to prolonged cold ischaemia time and at times difficult vascular reconstruction. Techniques such as in-situ splitting, machine perfusion and interposition grafts may address these challenges and thereby address these concerns. The aim of this review is to assess these technical advances in split liver transplantation, their utility and outcomes.

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Keywords included 'split liver transplantation', 'arterial reconstruction', and 'machine perfusion'. Data found was synthesised into sections including: methods of splitting, full-left full-right splitting, donor cholangiography, machine perfusion and arterial reconstruction.

A total of 78 articles met inclusion criteria after screening of 151 eligible articles. These were subdivided into the following categories: in-situ (25), ex-vivo (25), full-left full-right splitting (15), donor cholangiography (2), machine perfusion (6), and arterial reconstruction (5). The in-situ splitting technique reduces the cold ischaemia time compared to the ex-vivo technique which may improve graft quality and liver splitting during normothermic machine perfusion is a novel technique with the potential to incorporate the best aspects of both techniques. Interposition grafts are often required during split liver transplantation but have an increased risk of hepatic artery thrombosis.

Advancements in technique have allowed many of the unique challenges of split liver transplantation to be overcome. Overall, this supports the use of split liver transplantation in broader and riskier settings and we advocate for liver transplant surgeons to not hesitate in using these grafts liberally and expanding their recipient selection criteria.

The outcomes of split-liver transplantation are controversial. This study compared outcomes and morbidity after extended right lobe liver transplantation (ERLT) and whole liver transplantation (WLT) in adults. MEDLINE and Web of Science databases were searched systematically and unrestrictedly for studies on ERLT and its impact on graft and patient survival, and postoperative complications. Graft loss and patient mortality odds ratios (OR) and 95% confidence intervals (CI) were assessed by meta-analyses using Mantel-Haenszel tests with a random-effects model. Vascular and biliary complications, primary nonfunction, 3-month, 1-, and 3-year graft and patient survival, and retransplantation after ERLT and WLT were analyzed. The literature search yielded 10 594 articles. After exclusion, 22 studies (n = 75 799 adult transplant patients) were included in the analysis. ERLT was associated with lower 3-month (OR = 1.43, 95% CI = 1.09-1.89, P = 0.01), 1-year (OR = 1.46, 95% CI = 1.08-1.97, P = 0.01), and 3-year (OR = 1.37, 95% CI = 1.01-1.84, P = 0.04) graft survival. WL grafts were less associated with retransplantation (OR = 0.57; 95% CI = 0.41-0.80; P < 0.01), vascular complications (OR = 0.53, 95% CI = 0.38-0.74, P < 0.01) and biliary complications (OR = 0.67; 95% CI = 0.47-0.95; P = 0.03). Considering ERLT as major Extended Donor Criteria is justified because ERL grafts are associated with vasculobiliary complications and the need for retransplantation, and have a negative influence on graft survival.