Variations of the left and middle hepatic veins: application in living related hepatic transplantation

Pre-operative assessment of living liver donors' liver anatomy and volumes

Decades of experience supports LDLT as a favorable strategy to reduce waitlist mortality. The multiple regenerative pathways of hepatocytes and other hepatic cells justify the rationale behind it. Nonetheless, living liver donation is still underused and its broader implementation is challenging, mostly due to variability in practices leading to concerns related to donor safety. A non-systematic literature search was conducted for peer-reviewed original articles related to pre-operative evaluation of living liver donor candidates. Eligible studies were synthesized upon consensus for discussion in this up-to-date review. Review of the literature demonstrate that the importance of preoperative assessment of vascular, biliary and liver volume to ensure donor safety and adequate surgical planning for graft procurement is widely recognized. Moreover, data indicates that anatomic variants in vascular and biliary systems in healthy donors are common, present in up to 50% of the population. Therefore, comprehensive mapping and visualizations of each component is needed. Different imaging modalities are reported across practices and are discussed in detail. Lastly, assessment of liver volume must take into account several technical and donor factors that increase the chances of errors in volume estimation, which occurs in up to 10% of the cases. Experience suggests that maximizing donor safety and lessening their risks is a result of integrated experience between hepatobiliary and transplant surgery, along with multidisciplinary efforts in performing a comprehensive pre-operative donor assessment. Although technical advances have increased the accuracy of volume estimation, over- or under-estimation remains a challenge that needs further attention.

Laparoscopic left hemihepatectomy guided by real-time indocyanine green fluorescence imaging using the arantius-first approach

BACKGROUND AND OBJECTIVE

Laparoscopic hepatectomy approaches, including major hepatectomy, were rapidly developed in the past decade. However, standard laparoscopic left hemihepatectomy (LLH) is still only performed in high-volume medical centres. In our series, we describe our technical details and surgical outcomes of LLH.

METHODS

Thirty-nine patients who underwent LLH in our institute were enrolled in the study. Among these, 13 patients underwent LLH guided by real-time ICG fluorescence imaging using the Arantius-first approach (ICG-LLH group), and the other 26 underwent conventional LLH (conventional LLH group). Demographic characteristics and perioperative data were retrospectively collected and analysed. We compared the technical and postoperative short-term outcomes of the two groups.

RESULTS

There were no significant differences in the demographic or clinicopathological characteristics of the patients in the two groups. ICG-LLH required significantly fewer pringle manoeuvres (1 vs. 3 times, p < 0.0001), had a shorter parenchyma dissection time (26 vs. 78 min, p < 0.001), and required fewer vessel clips (18 vs. 28, p < 0.001). Although there was no significant difference, the ICG-LLH group had less bile leakage (0 vs. 5, p = 0.09) and less blood loss (120 vs. 165, p = 0.119). There were no significant differences in the overall complication or R0 resection rates between the two groups.

CONCLUSION

Our data demonstrate that laparoscopic left hemihepatectomy guided by real-time ICG fluorescence imaging using the Arantius-first approach is safe and feasible in selected patients, thus improving the fluency of the surgical procedure and postoperative short-term outcomes.

Surgical Anatomy of the Liver-Significance in Ovarian Cancer Surgery

INTRODUCTION

Ovarian cancer is the leading cause of death among all gynecological malignancies. Most patients present with an advanced stage of the disease. The routes of spread in ovarian cancer include peritoneal dissemination, direct invasion, and lymphatic or hematogenous spread, with peritoneal and lymphatic spread being the most common among them. The flow direction of the peritoneal fluid makes the right subphrenic space a target site for peritoneal metastases, and the most frequently affected anatomical area in advanced cases is the right upper quadrant. Complete cytoreduction with no macroscopically visible disease is the most important prognostic factor.

METHODS

We reviewed published clinical anatomy reports associated with surgery of the liver in cases of advanced ovarian cancer.

RESULTS

The disease could disseminate anatomical areas, where complex surgery is required-Morrison's pouch, the liver surface, or porta hepatis. The aim of the present article is to emphasize and delineate the gross anatomy of the liver and its surgical application for oncogynecologists. Moreover, the association between the gross and microscopic anatomy of the liver is discussed. Additionally, the vascular supply and variations of the liver are clearly described.

CONCLUSIONS

Oncogynecologists performing liver mobilization, diaphragmatic stripping, and porta hepatis dissection must have a thorough knowledge of liver anatomy, including morphology, variations, functional status, potential diagnostic imaging mistakes, and anatomical limits of dissection.

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.

Prevalence of hepatic vascular anomalies in consecutive contrast-enhanced computed tomography images — a retrospective observational study

Background

Liver is a complex, highly vascular organ, where anatomical variations are the norm. This study aimed to analyze all the three hepatic vascular anatomical variations in a single study which would help us understand the prevalence of hepatic vascular (arterial, portal, venous) anomalies in the population catered to by our institution.

Methods

A retrospective analysis of 545 contrast-enhanced CT scans was done from November 2019 from the institute PACS after satisfying the inclusion and exclusion criteria. The raw imaging data were processed in PACS software — Centricity™ Universal Viewer and Syngo.via Vb20 platform, for axial, coronal, and axial-oblique multiplanar reformation, maximum intensity projection (MIP), and volume rendering (VR) images. Data were analyzed in the three vascular phases to determine the anatomical variations. Analysis was done by two surgical residents in the division of HPB surgery, which was verified by a certified radiologist.

Results

There were no major differences in the prevalence rates of the vascular anomalies across gender and domicile distributions. The prevalence of normal hepatic artery and variant hepatic artery in our study was 69% and 31%, respectively. Accessory left hepatic artery (10%) was the most common hepatic artery variant in our study. Single RHV was seen in 77.4%, and other RHV variants like two RHV with common trunk, two RHV with independent drainage, and three RHV with common trunk contribute 22.6% of our study population. Accessory inferior RHV was seen in 19.8% of the study population. Normal portal vein anatomy was found in 81.1% in our study, and the most common variant in our study population was trifurcation of portal vein (16.1%).

Conclusion

This was the largest study until date from South India, studying all three hepatic vascular anatomical variations in a single study. Variations in the anatomy of hepatic arteries, portal veins, and hepatic veins are common. A good knowledge of the same is necessary especially for a hepatobiliary surgeon or for an interventional radiologist, to plan and avoid complications during a procedure. Preoperative contrast-enhanced CT scan and whenever necessary a VR or a MIP reconstruction will precisely help in identifying these variations.

Three-Dimensional Computed Tomography Scan Analysis of Anatomical Variations in the Hepatic Veins

Hepatic venous anatomy is a significant component of liver segmental anatomy, and its high variability is a challenge for hepatobiliary surgeons. This was a retrospective study of 98 consecutive patients with no cirrhosis or malignant tumors. IQQA-Liver software was used to display and analyze three-dimensional (3D) images of the hepatic veins and their branches and variations. The average liver volume was 1272.65 ± 322.04 mL; the left hepatic veins drained the smallest parts (21.13 ± 5.41%) of the liver compared with the right (35.58 ± 12.41%) and middle hepatic veins (34.64 ± 8.76%). The most common pattern was that the left hepatic veins shared a common trunk with the middle hepatic veins in 51cases (52.0%). The visualization rate of the inferior right hepatic vein (IRHV) was 43.9%, and its drainage volume was 179.27 ± 128.79 mL. In 11.2% of patients, the drainage volume for the IRHV was larger than for the right hepatic vein (RHV). The patterns of the left hepatic and middle hepatic veins were also observed and classified. Umbilical hepatic veins appeared in 75 cases (76.5%), and anterior fissure hepatic veins appeared in 74 cases (75.5%).The rate of the presence of a separate segment 4 vein was 15.3%, and 77 patients had obvious superficial veins. There was a statistically significant correlation between the diameter of the IRHVs and the drainage volume of the IRHVs and RHVs. More detailed information about the anatomical features and variations of hepatic venous veins in Chinese people was provided using 3D reconstructions, and this will assist in more precise liver surgeries.

Hepatic vein variations in 500 patients: surgical and radiological significance

OBJECTIVES

The purpose of the study was to assess the incidence of hepatic vein variations on multidetector CT (MDCT) for abdominal examinations.

METHODS

A retrospective analysis of 534 MDCT scans was performed in patients sent for various abdominal pathologies between January 2017 and April 2019. After excluding 34 patients, finally total of 500 patients (N = 500) were included in the study. For simplification, we classified the hepatic vein variations as classified by Soyer et al, Fang et al and Cheng et al.

RESULTS

Single right hepatic vein was seen in 458 (91.6%) out of 500 patients in our study. Two right hepatic veins were seen in 36 patients out of which 27 had common trunk and nine had independent drainage into the inferior vena cava (IVC). Common trunk of middle hepatic vein (MHV) and left hepatic vein (LHV) was seen in 405 (81%) and independent drainage of MHV and LHV into the IVC was seen in 95 (19%) of patients in our study. Amongst the segmental hepatic vein variations, most common drainage of segment IV vein was into LHV (333,66.6%) followed by MHV (148,29.6%) and IVC (19,3.8%).

CONCLUSION

Hepatic vein variations are commonly seen similar to variations in hepatic artery, portal vein and biliary anatomy. Knowledge of these variations is extremely important for transplant surgeons and intervention radiologists.

ADVANCES IN KNOWLEDGE

Awareness of the hepatic vein variations is essential for intervention radiologists and surgeons to reduce iatrogenic complications.

Preoperative volume calculation of the hepatic venous draining areas with multi-detector row CT in adult living donor liver transplantation: impact on surgical procedure

OBJECTIVE

The purpose was to assess the volumes of the different hepatic territories and especially the drainage of the right paramedian sector in adult living donor liver transplantation (ALDLT).

METHODS

CT was performed in 40 potential donors of whom 28 underwent partial living donation. Data sets of all potential donors were postprocessed using dedicated software for segmentation, volumetric analysis and visualization of liver territories. During an initial period, volumes and shapes of liver parts were calculated based on the individual portal venous perfusion areas. After partial hepatic congestion occurring in three grafts, drainage territories with special regard to MHV tributaries from the right paramedian sector, and the IRHV were calculated additionally. Results were visualized three-dimensionally and compared to the intraoperative findings.

RESULTS

Calculated graft volumes based on hepatic venous drainage and graft weights correlated significantly (r = 0.86, P < 0.001). Mean virtual graft volume was 930 ml and drained as follows: RHV: 680 ml, IRHV: 170 ml (n = 11); segment 5 MHV tributaries: 100 ml (n = 16); segment 8 MHV tributaries: 110 ml (n = 20). When present, the mean aberrant venous drainage fraction of the right liver lobe was 28%.

CONCLUSION

The evaluated protocol allowed a reliable calculation of the hepatic venous draining areas and led to a change in the hepatic venous reconstruction strategy at our institution.

Computerized CT-Based 3D Visualization Technique in Living Related Liver Transplantation

INTRODUCTION

For living donor liver transplantation (LDLT) accurate diagnostic workup is essential. Multiple imaging approaches are currently used. Problems arise in the assessment of vascular and bile duct anatomy, liver graft volume, and vascular territories involved. A 3D visualization system that improves anatomic assessment, allows interactive surgery planning, and acts as an intraoperative guide with enhanced precision is required. Refinements in computed tomography (CT) technology with the introduction of multidetector-row CT scanners and implementation of mathematical methods on computerized digital data has enabled CT-based 3D visualizations.

MATERIALS AND METHODS

Sixteen LDLT candidates and three LDLT recipients were assessed by multislice CT examination. Image processing of the digital raw data for 3D visualization included segmentation and calculation of center lines. A hierarchical mathematical model representing the vascular and biliary tree was created. This allowed calculation of individual vascular territories.

RESULTS

3D CT-based visualization in LDLT facilitates diagnostic workup with high accuracy for analyses of vascular and bile duct variants, volumetry, and assessment of the optimal surgical splitting line of the living donor liver. Resultant areas of either arterial devascularization or venous congestion can be displayed and quantified preoperatively. The diagnostic method is of major impact on patient selection and directly influences intraoperative surgical guidance. The currently practiced "multiple imaging approach" approach, especially with regard to invasive diagnostics, can be avoided in the future.

First two cases of living related liver transplantation with complicated anatomy of blood vessels in Beijing

AIM: Living related liver transplantation (LRLT) has been developed in response to the paediatric organ donor shortage. Though it has been succeeded in many centers worldwide, the safety of the donor is still a major concern, especially in donors with anatomy variation. We succeeded in performing the first two cases of living related liver transplantation with complicated anatomy of blood vessels as a way to overcome cadaveric organ shortage in Beijing.

METHODS: Two patients, with congenital liver fibrosis and congenital biliary atresia were performed with living donor liver transplantation in our hospital and then followed up from November 12 to December 13, 2001. The two living donors, mother and father, were healthy aged 34 and 35 years. One right lobe (segment V, VI, VII, VIII) and one left lateral lobe (segment II and III) were used. The grafts weighed 394 g and 300 g. The ratio of graft weight to the standard liver volume (SLV) of donors was 68% and 27%. The graft weight to recipient body weight ratio was 3.2% and 4.4%. The graft weight to recipient estimated standard liver mass (ESLM) ratio was 63% and 85%. The two donors had complicated blood vessel variation.

RESULTS: Two patients undergone living donor liver transplantation had good results. Abnormal liver function with high bilirubin level appeared in a few days after operation, but liver function returned to normal one month after operation with bilirubin level almost decreased to near normal. No bleeding, thrombosis, infection and bile leakage occurred. One had an acute rejection and recovered. The two donors recovered in two weeks. One had slight fever because of a little collection in abdomen and recovered after paracentesis and drainage.

CONCLUSION: Living donor liver transplantation has been proved to be a good way that offers a unique opportunity of getting a timely liver graft as a response to shortage of pediatric donors, though it could be a technically difficult operation if there is anatomical variation.

Hepatic venoplasty to overcome outflow block in living related liver transplantation

A 14-year-old boy with congenital biliary atresia underwent living related liver transplantation. Because of anatomic variation in donor hepatic vein, there were small and double orifices of hepatic veins in the harvested left hemiliver graft. To minimize the risk of outflow block after reperfusion, the recipient's native hepatic vein was used as an autologous patch for hepatic vein reconstruction. After 3 years of follow-up, the patient is alive and well with normal liver function. Follow-up duplex ultrasound scan showed adequate hepatic vein outflow without signs of late obstruction. The new technique of the autologous vascular patch grafting for successful hepatic vein reconstruction is described.

Adult living donor liver transplantation: current status

Living donor liver transplantation was developed in response to a shortage of full-size grafts for children. The progression from reduced-size cadaveric grafts to use of living donors occurred subsequent to expansion of liver anatomy knowledge and practical use of hepatic segments. A major benefit of pediatric live donor liver transplantation is the grafting of children without using livers from the cadaver donor pool. A major drawback of the procedure relates to the need to perform surgery and assign risk to an otherwise healthy individual. The ethical challenge has been discussed in detail and, although not ideal, the procedure "passes muster" on grounds of informed consent and the good of helping another human being. Formidable success appears to have been attained with the adult-to-adult procedure thus far; however, the transplant community still awaits center-specific and compiled data to determine whether the procedure truly reduces adult waiting list times for liver transplant recipients with minimal donor risk.

Superior diagnostic strength of combined contrast enhanced MR-angiography and MR-imaging compared to intra-arterial DSA in liver transplantation candidates

To evaluate the diagnostic value of combined contrast enhanced MRA (ce-MRA) and MRI compared to that of intra-arterial DSA (i.a.DSA) in liver transplantation, transjugular porto-systemic (TIPSS) and spleno-renal shunt candidates. 50 patients in the workup for liver transplantation underwent ce-MRA/MRI and i.a.DSA within a three days interval. Both examinations were assessed with respect to vessel anatomy and patency of the arterial, portal venous, porto-systemic collateral and systemic venous system. The results were compared with the intra-operative findings when available. Malignancy detection in ce-MRA/MRI and i.a.DSA were compared. There are no significant differences for the arterial part of the vascular supply to the liver that is important for transplantation. Although the differences for the portal system are not significant, the difference between the two techniques is of clinical importance because i.a.DSA failed to detect portal vein occlusion in 4 patients. Ce-MRA is significantly better for the detection of collaterals (p < 0.001) and the assessment of the inferior vena cava, the hepatic and the renal veins (p < 0.001). Although the detection of liver malignancy is poor in both techniques, ce-MRA/MRI is superior to i.a.DSA. This study shows that a one step diagnostic approach with a combination of ce-MRA and MRI is a valuable radiological tool with a superior diagnostic strength compared to i.a.DSA in the liver transplantation and shunt candidate. Therefore, ce-MRA/MRI should replace i.a.DSA in these patients groups.

Adult-to-adult living donor liver transplantation

Adult-to-adult living donor liver transplantation has become the subject of a great deal of attention over the last few years. Until the use of the donor right lobe was introduced and demonstrated to be relatively safe, it was not possible to offer this alternative to conventional transplantation to most adults. Recent clinical work has focused on the results of these procedures in both donors and recipients, perfecting surgical techniques for right-lobe transplantation, streamlining donor evaluation protocols, and containing costs. This overview summarizes many of the recent publications and presentations in the field of adult-to-adult living donor liver transplantation.

Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation

OBJECTIVE

This study was performed to document the impact of multidetector multiphase CT in facilitating patient selection and surgical planning in potential donors being evaluated for living adult right lobe liver transplantation.

SUBJECTS AND METHODS

Forty consecutive potential donors were included in the study. There were 26 men and 14 women, (age range, 18-57 years; mean, 37 years) We performed CT using a multidetector scanner, after IV injection of 180 mL of contrast material at 5 mL/sec. Arterial phase images were acquired at 18 sec (collimation, 1.25 mm; table speed, 7.5) and portal phase images, at 60 sec (collimation, 2.5 mm; table speed, 15). Postprocessing was performed on a commercially available workstation. CT data included dual-energy assessment of liver parenchyma for fatty infiltration; depiction of arterial, portal venous, and hepatic venous anatomy and identification of important vascular variants; and determination of total and lobar liver volume.

RESULTS

Of the 40 potential liver donors evaluated, 15 patients (37.5%) were excluded on the basis of CT findings, with most exclusions a result of portal vein anomalies (n = 8). Fatty infiltration resulted in four exclusions (10%), and small liver volume resulted in three exclusions (7.5%).

CONCLUSION

Multidetector multiphase CT provided comprehensive parenchymal, vascular, and volumetric preoperative evaluation of potential donors undergoing living adult right lobe liver transplantation. This information had a major impact on patient selection because it was used to stratify patients. It allowed the surgeons to plan their surgical approach, and this planning may reduce postoperative complications.

Right lobe living donor liver transplantation: a review

The continuing shortage of organs for adult transplant recipients has generated enthusiasm for adult-to-adult living donor liver transplantation (LDLT). The major concern has been the ability to resect a graft of adequate size without subjecting the donor to undue risk. The right hepatic lobe is generally large enough for adult recipients, but because of the real and perceived risks of right lobe (RL) resection, surgeons have been hesitant to offer this option to their patients. The first series of RL resections that included a significant number of patients was reported in 1999, and the results were encouraging. Only minor complications occurred in donors, and the recipients fared quite well. Enthusiasm for these donor resections is growing, and more centers are beginning to perform them. There is a good deal of global experience with pediatric LDLT but little with adults, and there are unique considerations in this population. This review examines donor selection criteria for adult recipients, highlights technical points critical for good outcome, and examines the early results and complications in both donors and recipients. If the preliminary results continue to be reproduced, RL LDLT could have significant impact on the worsening organ shortage.

Analysis of postoperative liver function of donors in living-related liver transplantation: comparison of the type of donor hepatectomy

BACKGROUND

There is a potentially significant risk to the donor in living-related liver transplantation.

METHODS

We analyzed surgical risk and stress to 35 donors in living-related liver transplantation with special reference to the types of donor hepatectomy. Donor surgery was performed in one of three ways: (1) lateral segmentectomy without ligation of the middle hepatic vein (MHV) in the remnant liver (group 1, n=21); (2) lateral segmentectomy with ligation of MHV in the remnant liver (group 2, n=6); and (3) left lobectomy with MHV (group 3, n=8).

RESULTS

No critical complications were observed in any group. The postoperative enzyme levels in group 2 were significantly higher than those in groups 1 and 3 (P<0.01). Although blood loss was covered by autologous blood transfusion in the first six cases, no banked blood was transfused in any of the cases. Surgical duration was significantly longer and blood loss was significantly greater in group 3 than in group 1 (P<0.05). Follow-up computed tomography showed atrophic changes in segment IV in groups 1 and 2. No remarkable changes were seen in segments V or VIII in any of the three groups.

CONCLUSION

Regardless of the donor hepatectomy procedure, serious complications did nor occur after surgery. Although it should be noted that the type of donor hepatectomy affects postoperative donor liver function, left lateral segmentectomy with ligation of MHV in the remnant liver is a useful method for obtaining liver grafts from living-related donors who have unusual anatomic variations of the hepatic veins.