Chapter 68: Hyperreduced Liver Grafts in Children under 10 kg in Weight

INTRODUCTION

Organ shortage is one of the main problems in pediatric liver transplantation. This situation is mainly due to the lack of donors with adequate size, being particularly critical in patients weighing less than 10 kg. When the ratio of graft size to recipient weight is greater than 5%, graft reduction may be necessary to prevent large-for-size syndrome (LFS). LFS is characterized by inadequate tissue oxygenation and graft compression; it is associated with vascular and biliary complications and accelerated acute cellular rejection.^1,2

Bismuth and Houssin initially described a liver reduction technique that allowed surgeons to partially compensate for the lack of pediatric donors.³ However, this technique can only be performed when the donors weight is less than 4 times that of the recipient, limiting it to pediatric patients of greater weight or to smaller patients when the donor was also pediatric. Strong et al. subsequently described the use of the left lateral section graft with an adult donor, allowing transplants, regardless of a wide disparity in weight between the donor and recipient.⁴ The split-liver transplantation technique and living related donor helped to further reduce mortality on the waiting list for pediatric patients. But until then, the maximum achieved reduction were segments 2 to 3, producing grafts that were still too big for children under 10 kg.

In the 1990s, Houssin et al. described a new reduction technique when resecting segment 3 after implanting the left lateral section, presenting technical difficulties due to hemostatic disorders in the newly vascularized liver.⁵ Strong et al. described a case in which segment 3 was implanted after the resection of segment 2 on the back table.⁶ Later, Mentha et al. reported a segment 2 implant from a cadaveric donor after the resection of segment 3.⁷

These techniques found their ultimate expression in the hyperreduction technique, where the left lateral section dimensions are reduced for a graft implant composed of portions of segments 2 and 3, adapting the graft to the size of the recipient. In this technique, which we have been practicing since 1997, the reduction is carried out in situ.^8,9 The procedure is performed in the donor before clamping the vascular pedicle, discarding ischemic areas in the graft, which in contrast, are difficult to diagnose on the back table. We consider it unnecessary to be strictly anatomic in the construction of a monosegment, as some authors have reported, because the approach of the biliary pedicle of the left lateral section can make the transplant technically more complex. Furthermore, we can avoid complications from anatomic variations (especially in cadaveric donors) by protecting the hilar pedicle dissection from segments 2 to 3. Such hyperreduction allows the tailoring of grafts according to the recipient’s abdominal volume (especially the anteroposterior diameter) and the donor’s liver size.

All donor vascular hepatic anatomy was studied using computed tomography (CT) angiography and/or conventional ...