EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Liver transplantation (LT) remains the cornerstone of modern transplant programs worldwide, with decea-sed donor liver transplantation (DDLT) representing the predominant modality. Despite evolving allocation systems and increasing acceptance of extended-criteria grafts, organ availability continues to fall short of demand. Maximizing the use of available donor organs therefore remains a central priority.
In living donor liver transplantation (LDLT), detailed preoperative imaging enables comprehensive assessment of vascular and biliary anatomy, and anatomical variants are typically identified before donor selection. In contrast, DDLT frequently pro-ceeds without complete cross-sectional imaging, and unexpected anatomical variations may only become apparent during organ procurement or back-bench preparation.
Arterial anatomical variants are well recognized in LT and may influence graft usability, particularly when complex reconstruction is required.¹ In contrast, portal vein (PV) variations, although relatively common, are typically intrahepatic and are usually surgically manageable and rarely constitute a contraindication to LT.^2,3
Here, we report an unusual extrahepatic PV configuration identified during back-bench prepara-tion of a deceased donor graft that precluded safe transplant. Although duplication and complex extra-hepatic portal venous variants have been described in radiological and case-based literature,^4-8 their impact on graft use in DDLT remains underreported. This study was conducted in accordance with institu-tional ethical standards, and no identifiable patient information has been included.
A 42-year-old male donor had a subarachnoid hemorrhage and was declared brain-stem dead. The donor had a history of moderate alcohol intake; however, liver biochemistry was normal and the graft was accepted for LT. Organ retrieval was performed by an external procurement team, and the graft was subsequently assessed on the back bench at the implant center before being declined and referred to our unit.
During back-bench inspection, our unit identified an unusual PV anatomy. The right and left portal inflow branches appeared to enter the liver separately and were intimately associated with the common bile duct, which lay between them and was not amenable to safe separation. In addition, a distinct posterior portal venous trunk was identified, supplying portions of both the right and left liver, as confirmed by probing (Figure 1). Importantly, this configuration represented native donor anatomy rather than procurement-related division, as confirmed during back-bench assessment.
The configuration raised significant concerns regarding the feasibility of safe vascular reconstruction. The interposition of the bile duct between portal branches precluded secure dissection and, even if complex reconstruction were attempted, would carry a high risk of compromising both portal inflow and biliary drainage.
Given the complex anatomy and the recipient’s partial PV thrombosis, reliable reconstruction ensuring adequate portal inflow could not be guaranteed. The graft was therefore deemed unsuitable for LT.
From an embryological perspective, PV variations arise from complex remodeling of the vitelline venous system. During early development, paired vitelline veins form 3 communicating anastomoses around the developing duodenum, which subsequ-ently undergo selective involution and persistence to form the PV trunk and its intrahepatic branches. Disruptions in this process give rise to a wide spectrum of anatomical variants, including duplication and aberrant extrahepatic branching patterns.⁹
While duplication and even triplication of the PV have been described in isolated radiological reports, these anomalies are typically incidental findings iden-tified during imaging for unrelated conditions and are rarely associated with surgical contraindications.^4,6-8 In the available literature, descriptions have focused on portal venous anatomy, with limited or no assessment of the biliary relationships, likely reflecting their lack of clinical relevance in those reports.^4,6-8
In contrast, the present configuration, characte-rized by multiple extrahepatic portal inflow trunks intimately related to the extrahepatic biliary tree, represents a particularly challenging anatomical scenario. The close interdigitation of portal branches with the bile duct precluded safe separation, ren-dering both standard and complex portal reconstruc-tion options unreliable and placing both vascular inflow and biliary drainage at risk.
This case suggests that PV variants involving multiple extrahepatic trunks with inseparable biliary relationships may represent a relative contraindi-cation to transplant in selected cases.
In retrospect, earlier recognition of this anatomy during procurement may have allowed retrieval of a longer portal venous segment, potentially including the confluence with the superior mesenteric and splenic veins, if present. Such an approach might theoretically have facilitated reconstruction by enabling separation of distal biliary structures on a lower level and thus providing additional length for complex portal reconstruction. However, this remains speculative, and the feasibility of biliary preservation in such configurations is uncertain. The rarity and complexity of these variants make intraoperative recognition challenging, even for experienced pro-curement teams.
In an era of persistent organ shortage, continued efforts to maximize utilization of donor organs while maintaining recipient safety remain essential. Although PV variations are encountered in up to 10% to 20% of donors and are usually amenable to surgical reconstruction, extreme extrahepatic configurations involving multiple inflow branches and intimate biliary relationships may occasionally preclude safe implantation.^2,3
This case highlights that, although portal venous variants are usually manageable, extreme extrahepatic configurations may directly influence graft utilization and represent a potential cause of graft discard during back-bench assessment. Recognition of such anato-mical variants during procurement and back-bench evaluation is therefore critical, as they may determine graft usability and help avoid futile transplant procedures.

Volume: 24 Issue: 7 July 2026

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