Graft reduction in pediatric liver transplantation: The myth of 4?

Anatomical Variations of Left Hepatic Vein and Outflow Reconstruction Techniques in Paediatric Living Donor Liver Transplantation

Anatomical variations of left hepatic vein (LHV) are observed in nearly a third of left lateral segment (LLS) donors in living donor liver transplantation (LDLT). There is paucity of studies and no structured algorithm for customised outflow reconstruction in LLS grafts with variant anatomy. Analysis of a prospectively collected database of 296 LLS paediatric LDLT was done to identify different venous drainage patterns of segments 2 (V2) and 3 (V3). LHV anatomy was classified into three types: type 1(n=270, 91.2%): V2 and V3 joined to form a common trunk which drains into middle hepatic vein (MHV)/inferior vena cava (IVC), subtype 1a length of trunk ≥ 9mm and subtype 1b length of trunk < 9mm; type 2(n=6, 2%): V2 and V3 drain independently into IVC; type 3(n=20, 6.8%): V2 and V3 drain into IVC and MHV respectively. Analysis of post-operative outcomes between LLS grafts with single and reconstructed multiple outflows showed no difference in the occurrence of hepatic vein thrombosis/stenosis, major morbidity (p 0.91) and 5 year survival (log rank p 0.562). This classification is a simple yet effective tool for pre-operative donor assessment and we propose a schema for customised reconstruction of LLS grafts, with excellent and consistently reproducible outcomes.

Advanced preoperative three-dimensional planning decreases the surgical complications of using large-for-size grafts in pediatric living donor liver transplantation

BACKGROUND

Using "large-for-size" liver graft, graft-to-recipient weight ratio (GRWR) ≥4%, has been debated in pediatric liver transplantation due to possible graft compartment after abdomen closure. Meticulous preoperative evaluation with three-dimensional (3D) techniques may prevent these problems. This study compared the safety of large-for-size grafts in pediatric living donor liver transplantation (PLDLT) during the eras with or without 3D planning.

METHODS

We defined the 3D era was after November 2017 due to our first implication of 3D printing for surgical planning and subsequently developing a 3D simulation implanting model. From November 2004 to July 2021, we enrolled 30 PLDLT patients with body weight (BW) < 10 kg and categorized them into conventional group: GRWR ≥4% before the 3D era (n = 9), 3D group: GRWR ≥4% in the 3D era (n = 8), and control group: GRWR <4% (n = 13). We followed and compared their clinical outcomes.

RESULTS

The 3D group had the lowest BW and the highest graft volume reduction rate, with all receiving modified left lateral segments (LLS), such as reduced LLS (n = 2), hyperreduced LLS (n = 5), and segment 2 monosegment (n = 1). Overall postoperative complications were similar in conventional and control groups but significantly lower in the 3D group (OR 0.06, 95% CI 0.006-0.70, p = 0.025). However, all groups had similar graft and patient survival at 1, 2, and 4 years.

CONCLUSION

Advanced preoperative 3D planning can decrease post-transplant complications and increase the safety of large-for-size grafts in PLDLT.

LEVEL OF EVIDENCE

Type of study: Retrospective comparative study; Evidence level: Level III.

Delayed sequential abdominal wall closure in pediatric liver transplantation to overcome "large for size" scenarios

BACKGROUND

Primary abdominal wall closure after pediatric liver transplantation (PLT) is neither always possible nor advisable, given the graft-recipient size discrepancy and its potential large-for-size scenario. Our objective was to report the experience accumulated with delayed sequential closure (DSC) guided by Doppler ultrasound control.

METHODS

Retrospective analysis of DSC performed from 2013 to March 2020.

RESULTS

Twenty-seven DSC (26.5%) were identified out of 102 PLT. Transplant indications and type of grafts were similar among both groups. In patients with DSC, mean weight and GRWR were 9.4 ± 5.5 kg (3.1-26 kg) and 4.7 ± 2.4 (1.9-9.7), significantly lower and higher than the primary closure cohort, respectively. The median time to achieve definitive closure was 6 days (range 3-23 days), and the median number of procedures was 4 (range 2-9). Patients with DSC had longer overall PICU (22.5 ± 16.9 vs. 9.1 ± 9.7 days, p < .05) and hospital stay (33.4 ± 19.1 vs 23, 9 ± 19.8 days (p < .05). These differences are less remarkable if the analysis is performed in a subgroup of patients weighing less than 10 kg. Two patients presented vascular complications (7.4%) within DSC group. No differences were seen when comparing overall, 3-year graft and patient survival (96% and 96% in the DSC group).

CONCLUSIONS

DSC is a simple and safe technique to ensure satisfactory clinical outcomes to overcome "large for size" scenarios in PLT. In addition, we were able to avoid using a permanent biological material for closing the abdomen.

Robotic monosegment donor hepatectomy for pediatric liver transplantation: First report

BACKGROUND

LT for infants less than 5 kg remains a challenge with high technical complication rates, which is further compounded by large-for-size grafts requiring hyper-reduction. The benefits of MIDH especially for standard left lateral segment (LLS) resection have been unequivocally demonstrated. However, given the fine margins of error, the highly challenging technical aspects of anatomical graft reduction test the limits of safety and may not be routinely feasible with the conventional laparoscopic approach.

CASE REPORT

A 14-month-old girl weighing 4.4 kg with extrahepatic biliary atresia was referred to our unit for an LT. Her mother volunteered to donate and the calculated volume of the LLS was 342 ml, with an estimated GRWR of 7.6. Given the extremely high GRWR, a segment II monosegment graft was planned. A RMDH was performed, with a final GRWR of 4. The donor and recipient were discharged on the 5th and 12th post-operative days, respectively.

CONCLUSION

We present the first-ever report of an RMDH. Our report highlights the fact that robotic surgery can safely replicate a highly precise surgical operation, thereby safely pushing the limits of MIDH.

Uncommon presentation of a recurrent diaphragmatic hernia after pediatric liver transplantation

DH is a rare but well-recognized complication of PLT. However, a recurrent DH in the setting of PLT has not been reported. We report the case of a child who had previously undergone a DH repair early after PLT and presented more than two years later with atypical findings of severe sepsis and a tender abdominal swelling.

Pediatric living donor liver transplantation with large-for-size left lateral segment grafts

Usage of "large-for-size" left lateral segment (LLS) liver grafts in children with high graft to recipient weight ratio (GRWR) is controversial due to concerns about increased recipient complications. During the study period, 77 pediatric living donor liver transplantations (LDLTs) with LLS grafts were performed. We compared recipients with GRWR ≥2.5% (GR-High = 50) vs GRWR <2.5% (GR-Low = 27). Median age was higher in the GR-Low group (40 vs 8 months, P> .0001). Graft (GR-High: 98%, 98%, 98% vs GR-Low: 96%, 93%, 93%) and patient (GR-High: 98%, 98%, 98% vs GR-Low: 100%, 96%, 96%) survival at 1, 3, and 5 years was similar between groups (P = NS). Overall complications were also similar (34% vs 30%; P = .8). Hepatic artery and portal vein thrombosis following transplantation was not different (P = NS). Delayed abdominal fascia closure was more common in GR-High patients (17 vs 1; P = .002). Subgroup analysis comparing recipients with GRWR ≥4% (GR-XL = 20) to GRWR <2.5% (GRWR-Low = 27) revealed that delayed abdominal fascia closure was more common in the GR-XL group, but postoperative complications and graft and patient survival were similar. We conclude that pediatric LDLT with large-for-size LLS grafts is associated with excellent clinical outcomes. There is an increased need for delayed abdominal closure with no compromise of long-term outcomes. The use of high GRWR expands the donor pool and improves timely access to the benefits of transplantation without extra risks.