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INTRODUCTION
Replacement of the retrohepatic inferior vena cava (IVC) after concurrent resection of IVC and hepatocellular carcinoma (HCC)-containing liver is settled as an optional technique of living donor liver transplantation (LDLT) to cope with HCCs around the IVC.1234 This technique makes the resection extent of LDLT comparable to that of deceased-donor liver transplantation (DDLT). In the current Korean setting, the common substitute for IVC is a Dacron graft for adult recipients. In contrast, such a synthetic graft cannot be used for pediatric patients because of ongoing physical growth. Thus, homograft should be used. There are only few cases on IVC replacement in pediatric LDLT.5 We herein present one case of IVC replacement performed during pediatric LDLT to treat advanced hepatoblastoma.
CASE
The patient was an 8 year-old 28 Kg-weighing boy suffering from large multiple hepatoblastomas, partially responsive to systemic chemotherapy (Fig. 1). The tumors encroached the retrohepatic IVC. Thus, there was high risk of residual tumor cells attached at the IVC, if it was preserved (Fig. 2). Thus we decided to replace IVC at the time of LDLT operation. Since we did not have any cryopreserved IVC allograft as well as we were reluctant to use cryopreserved vein allograft for pediatric patients because of high risk of late aneurysmal weakening or shrinkage, we waited until suitable large-sized vein allograft was available.
After waiting for more than one month, we finally obtained cold-stored IVC allograft, recovered from a deceased organ donor. A 250 g-weighing left liver graft was harvested from his 42 year-old mother and the 4 cm-long IVC allograft was anastomosed at the back table. Since such a length of IVC allograft was too short to replace the resected recipient's IVC, another vein homograft patch was attached to elongate the IVC interposition graft (Figs. 3 and 4).
Recipient's native liver including the retrohepatic IVC was removed completely (Fig. 5). The left liver graft with IVC interposition was implanted along standard procedure (Fig. 6). After completion of reconstruction, the potentially tumor-invaded right diaphragm was excised, and repaired primarily (Fig. 7). Thereafter, indocyanine green (ICG) fluorescent imaging was applied to identify any remaining tumor, in which no abnormal fluorescent image was detected.
Since the liver graft was relatively very small compared with the 2064 g-weighing tumor-bearing native liver, a tissue expander was placed to prevent rotation toward the right subphrenic fossa. The tissue expander was removed after 2 weeks (Fig. 8).
This patient recovered uneventfully and is doing well for 3 months to date. He is currently undergoing scheduled adjuvant chemotherapy.
DISCUSSION
Compared with DDLT, LDLT has a definite demerit on oncological aspect in patients with hepatic malignancy because the recipient IVC should be preserved. If the IVC can be removed concurrently during LDLT operation, the extent of hepatectomy becomes comparable to that of DDLT. In clinical practice for LDLT, IVC replacement has been performed for the patients with HCCs closely located to the IVC or Budd-Chiari syndrome.123456
In the current Korean setting, the common substitute for IVC is Dacron graft for adult recipients.6 This synthetic vessel institutes provides a large diameter, which exceeds the usual diameter of normal IVC, thus it is suitable for partial liver implantation. However, such a synthetic graft cannot be used for pediatric patients because of ongoing growth. There have been only few reports on IVC replacement in pediatric LDLT.5 The biggest hindrance against IVC replacement is availability of sizable vein homograft in countries where pediatric LDLT is frequently performed but the incidence of deceased donors is not high.
After deciding to perform LDLT with IVC replacement in this case, we had to wait for more than one month to obtained a fresh cold-stored IVC homograft, which was recovered from a deceased organ donor. The homograft was retrieved after obtaining a written consent on tissue donation and registered to the tissue bank at our institution. At this time, we urgently scheduled the LDLT operation just after confirmation of negative bacteria culture finding. To use the IVC homograft in a fresh state, it can be stored in 4℃ within 7 days instead of cryopreservation. Since the length of 4 cm was too short to replace the whole length of IVC resection, this homograft was elongated with other patches of vein homograft.
In this case, we applied intraoperative ICG fluorescent imaging to identify any remaining tumor. Yamamichi et al reported their experience that ICG fluorescent imaging was useful for surgical navigation in 3 hepatoblastoma patients and concluded that intraoperative ICG fluorescence imaging for patients with hepatoblastoma was feasible and useful for identifying small viable lesions and confirming that no remnant tumor remained after resection.7 We suggest injecting ICG dye intravenously more than 24 hours before operation, to make ICG accumulate at the tumor tissue.
In this case, the abdominal cavity was distended due to enlarged liver with large multiple tumors, but the liver graft was much smaller than the liver size. To place the left liver graft in the right position, we inserted a tissue expander to support the liver graft. We are not reluctant to insert a tissue expander if indicated. Mechanical support using a tissue expander is one of the standard procedures for pediatric LDLT developed many years ago.8 If the partial liver graft is large enough compared with the abdominal cavity, a slight dextro-positioning of the graft can be beneficial to hemodynamics-compliant hepatic vein reconstruction as well as stable positioning of the liver graft.
In pediatric recipients, various vein homografts such as iliac vein, IVC and other large-sized veins can be used depending on body size of the recipient and availability of vessel graft. We emphasize cryopreserved veins should be avoided if possible for pediatric patients because they can degenerate over time. Sasaki et al presented IVC replacement using a cryopreserved IVC homograft in a 10 year-old pediatric patient with Budd-Chiari syndrome.5
In conclusion, IVC replacement with homograft is a feasible option of LDLT in pediatric patients with advanced liver malignancies.
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