Controlled hepatic bipartition for transplantation in children

Surgical anatomy of the left lateral segment as applied to living-donor and split-liver transplantation: a clinicopathologic study

OBJECTIVE

To evaluate intrahepatic vascular and biliary anatomy of the left lateral segment (LLS) as applied to living-donor and split-liver transplantation.

SUMMARY BACKGROUND DATA

Living-donor and split-liver transplantation are innovative surgical techniques that have expanded the donor pool. Fundamental to the application of these techniques is an understanding of intrahepatic vascular and biliary anatomy.

METHODS

Pathologic data obtained from cadaveric liver corrosion casts and liver dissections were clinically correlated with the anatomical findings obtained during split-liver, living-donor, and reduced-liver transplants.

RESULTS

The anatomical relation of the left bile duct system with respect to the left portal venous system was constant, with the left bile duct superior to the extrahepatic transverse portion of the left portal vein. Four specific patterns of left biliary anatomy and three patterns of left hepatic venous drainage were identified and described.

CONCLUSIONS

Although highly variable, the biliary and hepatic venous anatomy of the LLS can be broadly categorized into distinct patterns. The identification of the LLS duct origin lateral to the umbilical fissure in segment 4 in 50% of cast specimens is significant in the performance of split-liver and living-donor transplantation, because dissection of the graft pedicle at the level of the round ligament will result in separate ducts from segments 2 and 3 in most patients, with the further possibility of an anterior segment 4 duct. A connective tissue bile duct plate, which can be clinically identified, is described to guide dissection of the segment 2 and 3 biliary radicles.

The role of magnetic resonance imaging and spectroscopy in transplantation: from animal models to man

Critical success factors in solid organ and vascular transplantation are the assessment of graft status/viability as well as stringent monitoring of transplant recipients, preferentially using noninvasive techniques. This review addresses the application of magnetic resonance imaging (MRI) and spectroscopy (MRS) in the field of transplantation. The first section is devoted to the description of the main MR techniques used for monitoring the status of the graft noninvasively. Subsequently, the role of MRI/MRS in the analysis of the viability of organs for transplantation is discussed. Since chronic rejection remains a major difficulty, development of new therapies is still ongoing. Thus, the third part is devoted to the use of MRI/MRS for monitoring graft rejection in animal models of transplantation. This is followed by a discussion of clinical studies of transplantation involving MRI/MRS. Finally, a general appraisal is made on available imaging techniques for the non-invasive characterization of grafts in situ, highlighting the role of MR methods in the field of transplantation.

Preserved vascular homograft for revascularization of pediatric liver transplant: a clinical, histological, and bacteriological study

BACKGROUND

Arterial or venous homografts are frequently implanted for vascular reconstruction in orthotopic liver transplantation (OLT). When fresh vascular homografts (VH) from the same donor were not available, VH from another donor preserved at 4 degrees C in Terasaki (Ter) solution (modified lymphocyte culture medium) were used.

METHODS

The clinical results after implantation of Ter-stored VH versus fresh VH in the revascularization of pediatric OLT were studied retrospectively. Short- and long-term follow-up of vascular patency was carried out by doppler ultrasonography in each case. A histological and bacteriological study of nonimplanted VH stored at 4 degrees C in saline (Sal), Ter and University of Wisconsin (UW) solutions for various time periods (days 0-28) was also undertaken.

RESULTS

Between 1989 and 1996, 21 iliac arteries and 21 iliac veins preserved in Ter solution (mean preservation time: 8 days; range 1-26) and 100 fresh VH (68 arteries and 32 veins) (preservation time: 8 hr, range 4-21) were used in pediatric OLT. Thrombosis rates were 0 of 21 for stored arteries vs. 7 of 68 (10%) for fresh arteries (NS) and 3 of 21 (14%) for stored veins vs. 3 of 32 (9%) for fresh veins (NS). Actuarial graft survival rates were similar in both groups. Histological analysis of stored, nonimplanted VH invariably showed endothelial destruction within 24-48 hr after procurement. The bacteriological study showed contamination rates of 14 of 25 (56%) for Sal-stored VH, 5 of 25 (20%) for UW, and 1 of 19 (5%) for Ter (Sal vs. UW and Sal vs. Ter: P<0.01; UW vs. Ter: NS).

CONCLUSIONS

Ter-preserved cadaveric VH could be safely used in OLT despite early destruction of endothelium.

Biliary complications of reduced-organ liver transplantation

Reduced-organ liver transplantation for children is effective in lowering pretransplantation morbidity and mortality. Improvements in surgical technique have reduced vascular complications; however, biliary complications continue to account for significant posttransplantation morbidity. This investigation chronicles the incidence and type of biliary complications encountered with reduced-organ liver transplantation. Retrospective review of reduced-organ liver recipients over a 59-month period was performed, and biliary complications were classified as (1) missed biliary radicle, (2) anastomotic leak requiring revision, and (3) biliary stricture. From July 1992 to May 1997, 42 children received reduced-organ grafts: 32 living-donor, 8 cadaveric-reduced, 1 split-liver, and 1 auxiliary orthotopic liver transplant. Of the 42 grafts, 41 were Couinaud segments II/III and 1 was segments II/III/IV. Ten biliary complications were identified in 9 recipients (24%). Biliary complications included parenchymal radicle leaks, 5 (50%); biliary strictures, 3 (30%); and anastomotic leaks, 2 (20%). Although technical advances have reduced the incidence of biliary complications secondary to organ ischemia, parenchymal radicle leaks continue to be a source of morbidity for reduced-organ recipients. Planned exploration on posttransplantation day 7 was performed on the most recent 26 of the 42 total reduced-organ procedures as a mechanism to identify and treat early technical complications. Planned exploration as a routine component of reduced-organ transplantation has yielded a 15% incidence of discovered parenchymal leaks and a 5% incidence of discovered anastomotic leaks. This series underscores the necessity for improved anatomical studies to correctly identify duct territories and the development of accurate noninvasive methods to assess the biliary system preoperatively and intraoperatively in the application of reduced-organ liver transplantation.

Three-dimensional reconstruction of the liver venous system using the preservation solution as contrast agent

To investigate whether MRI without using artificial contrast agents can provide sufficient image contrast to visualize the venous tree in the cold stored liver graft, two pig liver grafts were scanned with a multislice turbo spin-echo sequence with long TE (200 msec). The quality of the data obtained at 1-T field strength was sufficient for three-dimensional reconstruction of the hepatic vascular system, potentially useful for liver splitting surgery.

Magnetic resonance venography in liver bipartition procedures using preservation solution as contrast agent

To evaluate whether the hepatic veins can be visualized with a rapid noninvasive technique, and if so, whether the obtained images could be helpful in the preparation of split liver grafts for transplantation, six cold stored human donor livers were investigated with magnetic resonance imaging (MRI). The hepatic vein branches and their confluence were clearly visualized. Anatomic variations of the middle hepatic vein with consequences for the choice of the transection plane could be demonstrated. Furthermore, unexpected vascular abnormalities were detected. From these preliminary results it is concluded that visualization of the hepatic veins can be helpful in determining the feasibility of the bipartition procedure and the choice of the transection plane. A potential wide application of this fast and noninvasive technique is possible.

Controlled liver splitting for transplantation in two recipients: technique, results and perspectives

A technique of controlled liver splitting for transplantation in two recipients is proposed, based on a full anatomical assessment of the graft including arteriography and cholangiography on the back-table. Using eight livers, 16 patients received a graft: right liver (eight patients), left lobe (four) or left liver (four). Twelve patients required urgent or very urgent transplantation. Anatomical assessment of the graft demonstrated a portal bifurcation in all cases, a common trunk of the left and middle hepatic veins in five, a right biliary duplication in three and duplication of the left branch of the middle hepatic artery in one. After revascularization of the graft, bleeding was greater in patients with a right graft, particularly if the middle hepatic vein had been ligated. The main postoperative complications were hepatic artery thrombosis (four cases), biliary complications (four), portal vein thrombosis (two), haematoma (two) and abscess (two). No primary non-function of the graft was observed. The postoperative survival rate was 75 per cent. The four patients in whom transplantation was not considered urgent are still alive. The immediate survival rate of the grafts was 69 per cent. These results compare favourably with those in the literature. In spite of the technical, logistical and ethical problems raised by this technique, the results suggest that controlled liver splitting for transplantation in two recipients may in the future significantly improve the feasibility of liver transplantation.

Surgical techniques and innovations in living related liver transplantation

The authors successfully performed a series of 33 living related liver transplantations (LRLT) on children (15 males and 18 females, ranging from 7 months to 15 years of age) from June 1990 to May 1992, with the informed consent of their parents and the approval of the Ethics Committee of Kyoto University. Before operation, six of the children required intensive care, another 14 were hospitalized, and 13 were homebound. Donors (12 paternal and 21 maternal) were selected solely from the parents of the recipients on the basis of ABO blood group and graft/recipient size matching determined by computed tomography scanning. Procurement of graft was performed using ultrasonic aspirator and bipolar electrocautery without blood vessel clamping and without graft manipulation. All donors subsequently had normal liver function and returned to normal life. The left lateral segment (16 cases), left lobe (16 cases), or right lobe (one case) were used as grafts. The partial liver graft was transplanted into the recipient who underwent total hepatectomy with preservation of the inferior vena cava using a vascular side clamp. Twenty-seven of 33 recipients are alive and well with the original graft and have normal liver function. The patient survival rate was 89% (24/27) in elective cases and 50% (3/6) in emergent cases. The other six recipients had functioning grafts but died of extrahepatic complications. Complications of the graft were minimal in all cases. Hepatic vein stenosis, which occurred three times in two cases, was successfully treated by balloon dilatation. In cases with sclerotic portal vein, the authors anastomosed the portal vein of the graft to the confluence of the splenic vein and the superior mesenteric vein without a vascular graft, after experiencing a case of vascular graft thrombosis. After hepatic artery thrombosis occurred in one of the initial seven recipients whose arterial anastomosis was done with surgical loupe, microsurgery was introduced for hepatic artery reconstruction. There has been no occurrence of thrombosis since then. The current results with LRLT suggested that the meticulous management of surgical factors at each stage of the LRLT procedure is crucial for successful outcome. Living related liver transplantation is a promising option for resolving the graft shortage in pediatric liver transplantation and may be regarded as an independent modality to supplement cadaver donation.

Emergency liver transplantation for fulminant liver failure in infants and children

We report our results with orthotopic liver transplantation in children with fulminant liver failure. Thirty-five children with fulminant liver failure were evaluated for liver transplantation. The main causes of liver failure were viral hepatitis (54.2%), drug-induced liver injury (14.2%) and Wilson's disease (11.4%). Children were considered as candidates for liver transplantation only if hepatic encephalopathy was associated with a decrease in the level of factor V to below 25%. Seven children (20%) did not meet this criterion and recovered spontaneously. Six children (17.1%) had contraindications for liver transplantation and died. In three of these six children, contraindications included irreversible brain damage at the time of admission. Twenty-two children (62.8%) met the criteria for liver transplantation and were placed on the emergency transplant list. Three of them died awaiting grafts. Nineteen children underwent liver transplantation; 13 of them (68.4%) are alive without sequelae, after 6 mo to 4 yr of follow-up, at this writing. Four of the children who died after surgery had severe encephalopathy on admission that did not improve after liver transplantation. In conclusion, emergency liver transplantation appears to be an effective treatment for children with fulminant liver failure. Nevertheless, irreversible brain damage developed in 10 patients, and they died before or after surgery. We postulate that many of these deaths could have been avoided if children had been transferred to a liver transplantation facility and had undergone transplantation earlier. We emphasize that children with acute liver failure should be transferred to a center that performs liver transplantation before the development of hepatic encephalopathy.

Liver transplantation: the challenges of the 1990s

An enormous increase in liver transplantation has been observed over the last decade since it now represents a suitable therapeutic option for patients with end-stage liver disease. The overall one-year survival rate is about 75% for adults and 85% for children, when fulminant hepatic failure and malignancies are excluded. Such improvements in both survival and quality of life are due to many concurrent factors: better timing and selection; development of the UW solution for liver preservation; improvement in operative management including surgical technique, veno-venous bypass and cell-saver; progress in intensive care management of immunosuppressed patients. Nevertheless, the increasing demand for livers is now confronting the transplant teams with organ shortage, for which the introduction of graft reduction, hepatic biparition and living-related donation will contribute to alleviate the scarcity of donors. As a consequence of the increasing number of long-term survivors, greater efforts are now being directed towards the long-term outcome after liver transplantation: disease recurrence, the need for permanent immunosuppression and the quality of rehabilitation will become the challenges of the 1990s before reaching the next step towards multiple organ transplantation.