Impact of Medial Reduction of the Left Lateral Segment: A Novel Technique for Living Donor Liver Transplantation for Small Pediatric Recipients

Large-for-size syndrome prophylaxis in infant liver recipients with low body mass

Transplantation of the left lateral section (LLS) of the liver is now an established practice for treating advanced diffuse and unresectable focal liver diseases in children, with variants of the LLS primarily used in infants. However, the surgical challenge of matching the size of an adult donor's graft to the volume of a child's abdomen remains significant. This review explores historical developments, various approaches to measuring the required functional liver mass, and techniques to prevent complications associated with large-for-size grafts in infants.

"Reduced Size Liver Grafts in Pediatric Liver Transplantation; Technical Considerations"

Liver transplantation (LT) has become a vital treatment option for children with end-stage liver disease. Left lateral segment (LLS) grafts are particularly common in split and living donor LT for pediatric patients. However, challenges arise in small infants receiving LLS grafts, primarily due to graft-size mismatches, resulting in "large-for-size" grafts. To overcome this issue, the practice of further reducing grafts from the LLS to diminish graft thickness has been explored. Currently, the indication for reducing the thickness of LLS grafts includes recipients with a body weight (BW) under 5.0 kg, neonates with acute liver failure, or those with metabolic liver disease. At the National Center for Child Health and Development in Tokyo, Japan, among 131 recipients of reduced-size LLS grafts, a remarkable 15-year graft survival rate of 89.9% has been achieved in small infants. This success indicates that with experience and refinement of the technique, there's a trend towards improved graft survival in recipients with reduced-thickness LLS grafts. This advancement underscores the importance of BW-appropriate methods in graft selection to ensure exceptional outcomes in vulnerable pediatric patients in need of LT. These techniques' ongoing development and refinement are crucial in enhancing the survival rates and overall outcomes for these young patients.

Optimal graft size in pediatric living donor liver transplantation: How are children different from adults?

BACKGROUND

Pediatric liver transplantation is an established treatment for end-stage liver disease in children. However, it is still posing relevant challenges, such as optimizing the graft selection according to the recipient size. Unlike adults, small children tolerate large-for-size grafts and insufficient graft volume might represent an issue in adolescents when graft size is disproportionate.

METHODS

Graft-size matching strategies over time were examined in pediatric liver transplantation. This review traces the measures/principles put in place to prevent large-for-size or small-for-size grafts in small children to adolescents with a literature review and an analysis of the data issued from the National Center for Child Health and Development, Tokyo, Japan.

RESULTS

Reduced left lateral segment (LLS; Couinaud's segment II and III) was widely applicable for small children less than 5 kg with metabolic liver disease or acute liver failure. There was significantly worse graft survival if the actual graft-to-recipient weight ratio (GRWR) was less than 1.5% in the adolescent with LLS graft due to the small-for-size graft. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome. The suggested ideal graft selections in pediatric LDLT are: reduced LLS, recipient body weight (BW) < 5.0 kg; LLS, 5.0 kg ≤ BW < 25 kg; left lobe (Couinaud's segment II, III, IV with middle hepatic vein), 25 kg ≤ BW < 50 kg; right lobe (Couinaud's segment V, VI, VII, VIII without middle hepatic vein), 50 kg ≤ BW. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome.

CONCLUSION

Age-appropriate and BW-appropriate strategies of graft selection are crucial to secure an excellent outcome in pediatric living donor liver transplantation.

Anterior hepatic resection: A simple and safe technique for reducing the antero-posterior diameter of the liver graft for small pediatric recipients

BACKGROUND

The techniques involved in neonatal and infantile transplantation require approaches that can sculpt a left lateral segment (LLS) to the right shape and size and avoid large-for-size syndrome. The aim of this article is to describe the anterior hepatic resection (AHR) of the LLS in pediatric LDLT.

METHODS

A retrospective anatomical study of preoperative image studies, description of the technique for AHR, and short-term results.

RESULTS

The AHR was performed in eight cases. All donors were male, with average age, BW, and BMI of 28.3 ± 5.9 years, 74.2 ± 9.3 kg, and 24.3 ± 2.6 kg/m2, respectively. Donors were discharged at an average of 3.6 ± 0.8 days. The median recipient age and BW at transplantation were 6.9 (2.7 to 11) months and 5.9 (3.9 to 8) kg, respectively, and the recipient-to-donor body weight ratio (RDBW) was <0.1 in all but one case. The mean percentage reduction in graft weight and in the antero-posterior diameter were 33.2% ± 5.5% and 38.3% ± 12.6%, respectively. The average (SD) GRWR was 4.8% ± 1.7% before all the resections and 3.5% ± 1.0% after the procedures. Seven patients were primarily closed.

CONCLUSION

After LLS resection, a nonanatomical anterior resection of the LLS was accomplished without hilar vascular dissection to segments II/III. The final liver graft allowed primary abdominal wall closure in all but one patient, with meaningful adjustments in GRWR. AHR proved to be simple, safe, reproducible, and effective in the presented case series.

Predictors of portal vein complications after pediatric liver transplantation: A German center experience

BACKGROUND

Portal vein complications (PVCs) after pediatric liver transplantation (LT) are sometimes asymptomatic, especially in the early phase, and can threaten both the graft and patient's survival. Therefore, the purpose of this study is to analyze the risk factors for portal vein thrombosis (PVT) and portal vein stenosis (PVS) after pediatric LT.

METHODS

All pediatric patients (n = 115) who underwent primary LT at Regensburg University Hospital between January 2010 and April 2017 were included in this study. The pre-, intra-, and postoperative parameters of all patients were retrospectively reviewed and risk factors for both PVT and PVS were analyzed.

RESULTS

Of the 115 patients, living donor LT was performed on 57 (49.5%) patients, and biliary atresia was the primary diagnosis in 65 patients (56%). After pediatric LT, 9% of patients developed PVT, and 16.5% developed PVS. Patient weight ≤7 kg [odds ratio (OR) 9.35, 95% confidence interval (CI) 1.03-84.9, p = .04] and GRWR >3% (OR 15.4, 95% CI 1.98-129.5, p = .01) were the independent risk factors for the development of PVT and PVS, respectively upon multivariate analysis. The overall patient survival rates at 1, 3, and 5 years were 91%, 90%, and 89%, respectively, and there was no difference in patient survival among those with and without PVCs.

CONCLUSIONS

Pediatric patients with body weight <7 kg and/or receiving a graft with GRWR >3% may develop PVCs and so require certain surgical modifications, close follow-up, and prophylactic anticoagulant therapy following transplant.

Outcome of Pediatric Liver Transplants in Patients With Less Than 10 kg of Body Weight Is Not Worse

OBJECTIVES

Liver transplant in pediatric patients with body weight < 10 kg poses a challenge to the entire liver transplant team. Many reports have considered 10 kg to be a cutoff pointfor body weightforfavorable posttransplant outcomes. With evolving surgical techniques and postoperative management, there is potential to improve outcomes in this subset of recipients. We compared the outcomes in pediatric patients with body weight < 10 kg with those > 10 kg; also, we studied the factors of influence.

MATERIALS AND METHODS

We performed a retrospective analysis to evaluate the outcomes of liver transplants in pediatric patients with < 10 kg body weight. The cohort consisted of 90 children subdivided into the following 2 subgroups: group A (n = 35) with > 10 kg body weight at liver transplant and group B (n = 55) with < 10 kg body weight at liver transplant. We compared the following pretransplant characteristics between the groups: graft weight, graft-to-recipient weightratio, cold ischemia time, warm ischemia times, and liver transplant outcomes.

RESULTS

Pediatric End-stage Liver Disease score was significantly higher in group B (score of 24) versus group A (score of 18). Group B had significantly higher graft-to-recipient weight ratio (2.8 in group B vs 1.7 in group A). Graft function showed no significant difference between the 2 groups. Portal vein thrombosis was seen only in group B, whereas biliary leaks were observed among 5 patients in group B and 1 patientin group A. Patient survivalrate was higherin group B (86%) than in group A (77%).

CONCLUSIONS

Pediatric patients weighing < 10 kg have similarif not better survivalrates after liver transplant compared with patients > 10 kg. Advancements in surgical techniques and a careful monitoring for complications and timely intervention are important to facilitate these outcomes.