The minor hepatic veins: anatomy and classification

Tumour site is a risk factor for hepatocellular carcinoma after hepatectomy: a 1:2 propensity score matching analysis

Background

The effect of the anatomic location of HCC on the prognosis of patients after hepatectomy is currently unclear.

Methods

Patients who underwent hepatectomy were retrospectively enrolled and divided into the right tumour resection group (R group) and the left tumour resection group (L group) according to the tumour anatomic location. To avoid bias, 1:2 propensity score matching (PSM) analysis was used. Based on the survival data, disease-free survival (DFS) and overall survival (OS) were evaluated by the Kaplan–Meier method, and long-term survival analysis was performed. Cox proportional hazards regression was used to analyse the risk factors associated with postoperative prognosis.

Results

A total of 700 patients were enrolled in our study. After 1:2 PSM, 354 and 177 patients were enrolled in the R group and the L group, respectively, with comparable baseline characteristics. Survival analysis showed that patients in the L group had a significantly higher recurrence rate than patients in the R group (P = 0.036), but there was no significant difference in the survival rate (P = 0.99). Long-term survival analysis showed that the survival rate of the L group was lower than that of the R group (P < 0.01). Multivariate analysis showed that tumour location in the left liver was an independent risk factor for tumour recurrence (hazard ratio, 1.263; 95% CI, 1.005–1.587) and long-term survival (hazard ratio, 3.232; 95% CI, 1.284–8.134).

Conclusion

For HCC patients, the recurrence rate and long-term survival rate of left liver tumours were significantly higher than those of right liver tumours, indicating that the anatomical location of the tumour has a significant effect on the survival of HCC patients.

Trial registration Chinese Clinical Trial Registry, ChiCTR2100052407. Registered 25 October 2021, http://www.chictr.org.cn/showproj.aspx?proj=135500.

A practical study of the hepatic vascular system anatomy of the caudate lobe

Background

This study aimed to examine the inflow and outflow vascular system of the caudate lobe and determine its relevance to hepatobiliary surgery.

Methods

A total of 41 cadaveric liver specimens were dissected in 2019 to evaluate the inflow and outflow vascular system of the caudate lobe.

Results

The Glisson's pedicles of the paracaval portion were mainly from the right pedicle in 14 cases (34.15%), mainly from the left pedicle in 22 cases (53.66%), and equally from the left and right pedicle in 5 cases (12.19%). Many thick branches of the portal vein were found behind the plane consisting of the hilar plate and Arantius ligament, but none of them were thicker than 1 mm in front of the plane. All of the veins of the caudate lobe drained into the inferior vena cava (IVC) via the anterior face. There was an avascular zone without short hepatic veins (SHVs) consisting of loose connective tissue between the retrohepatic IVC and caudate lobe, with its length and width being 45-97 mm and 6-15 mm, respectively.

Conclusions

The plane consisting of the hilar plate and Arantius ligament can be regarded as the boundary between the caudate lobe and the other lobes. There is an avascular zone without SHVs consisting of loose connective tissue between the retrohepatic IVC and caudate lobe.

Feasibility of Right Upper Transversal Hepatectomy in the Absence of an Inferior Right Hepatic Vein: New Insights regarding This Complex Procedure

Background

Right upper transversal hepatectomy (RUTH) is defined as the removal of liver segments 7, 8, and 4A with ligature of the right and middle hepatic veins and is considered one of the most complex techniques of parenchymal-sparing hepatectomies. This procedure can be performed, without venous reconstruction, if collateral veins are present communicating within remnant liver segments to a large inferior right hepatic vein and/or to the left hepatic vein. This venous network could maintain outflow from the inferior right segments (S5, S6) to the left liver when a RUTH is performed, even in the absence of an inferior right hepatic vein. The aim of this study is to present our experience with RUTH without venous reconstruction in patients with and without the presence of an inferior right hepatic vein (IRHV).

Methods

Patients submitted to RUTH for treatment of liver metastases were selected from our database. The presence of an IRHV, clinical and surgical characteristics of the patients, immediate outcomes, viability of liver segments 5 and 6, and long-term survival were analyzed.

Results

RUTH was successfully performed in four patients. In two patients, IRHV was not present, but intrahepatic communicating veins between proximal right and middle hepatic veins and left hepatic vein were present. No venous reconstructions were performed. Mild congestion of the inferior right segments occurred in the patients where there was no IRHV but no immediate, early, or late complications were observed.

Conclusions

RUTH is feasible and can be performed even in the absence of an IRHV, without venous reconstruction. Some degree of congestion of the right inferior liver segments might occur when an IRHV is absent, yet this is not clinically significant when communicating veins are present. Maximum parenchyma preservation might prevent postoperative liver failure and allow repeated resections in case of hepatic recurrence.

Reconstruction of Inferior Right Hepatic Veins in Living Donor Liver Transplantation

BACKGROUND

A proper knowledge of the anatomy of the liver (including its vascular particularities) is mandatory in cases which are going to be submitted to major hepatic resection, including living donor liver transplantation.

CASE REPORT

We present the case of a living donor liver transplantation in which a particularity of the anatomy of the hepatic veins was reported for the donor: two inferior hepatic veins for segments 5 and 6. This particularity imposed the need for creation of a supplemental anastomosis in the recipient: a phleboplasty of the two inferior veins followed by direct re-implantation into the inferior cava vein. However, the postoperative course was uneventful for both the donor and the recipient.

CONCLUSION

In certain cases presenting vascular particularities such as two inferior hepatic veins, phleboplasty followed by reimplantation into the inferior cava vein might be needed in order to provide a good vascular outflow of the liver graft.

Anatomy of the retrohepatic tunnel in a Chinese population and its clinical application in liver surgery

Liver hanging maneuver (LHM) is an important technique in liver surgery. However, applied anatomy of the retrohepatic tunnel for the surgical approach in Chinese population needs further study. In this study, to explore the basic anatomy of retrohepatic tunnel and its clinical application in a Chinese population, a total of 32 formalin-fixed cadavers were dissected, related parameters were measured, and their clinical applications were discussed. The length of the retrohepatic tunnel was (60.6 ± 9.9) mm. The width of the retrohepatic tunnel superior opening was (13.8 ± 3.9) mm. The width of the retrohepatic tunnel inferior opening was (15.2 ± 7.4) mm. The hepatic short vessels were distributed along the middle and lower 1/3 of hepatic inferior vena cava (HIVC), with a slight predominance on its left wall. A few hepatic short vessels were distributed along the upper 1/3 of the HIVC. We concluded: the anatomy of the retrohepatic tunnel provides a basis for use of LHM in liver surgery; more hepatic short vessels from hepatic caudate lobe can be preserved via right approach. The retrohepatic tunnel can be used as a good surgical approach in liver surgery; its application also has important significance in laparoscopic minimally invasive liver surgery.

The clinical anatomy of the inferior vena cava: a review of common congenital anomalies and considerations for clinicians

Anomalies in the course and drainage of the Inferior Vena Cava (IVC) may complicate normal functioning, correct diagnosis, and therapeutic interventions within the abdomen. Development of the IVC occurs during the 4th to 8th week of gestation, and due to its developmental complexity, there are many opportunities for malformations to occur. Although most IVC anomalies are clinically silent and are usually discovered incidentally on abdominal imaging, aberrations may be responsible for formation of thrombosis, back pain, and anomalous circulation of blood to the heart. In this review, we will discuss the most common variations and abnormalities of the IVC, which include the posterior cardinal veins, the subcardinal veins, the supracardinal veins, persistent left IVC, IVC duplication, situs inversus, left retroaortic renal vein, left circumaortic renal collar, scimitar syndrome, and IVC agenesis. For each abnormality outlined above, we aim to discuss relevant embryology and potential clinical significance with regards to presentation, diagnosis, and treatment as is important for radiologists, surgeons, and clinicians in current clinical practice.

Could transesophageal echocardiography be useful in selected cases during liver surgery resection?

PURPOSE

Although only limited scientific evidence exists promoting the use of transesophageal echocardiography (TEE) in non cardiac surgery, several recent studies have documented its usefulness during liver surgery.

METHODS AND RESULTS

In the present case study, through the use of color Doppler TEE, compression of the inferior vena cava and the right hepatic vein was clearly evident, as was their restoration after surgery.

CONCLUSION

TEE should be encouraged in patients undergoing liver resection, not only for hemodynamic monitoring, but also for its ability to provide information about the anatomy of the liver, its vessels, and inferior vena cava patency.

Hepatic veins anatomy and piggy-back liver transplantation

BACKGROUND

The piggy-back caval anastomosis technique is widely used in orthotopic liver transplantation although it carries an increased risk of complications, including outflow obstruction and Budd-Chiari syndrome. The aim of this study is to clarify the anatomy and variations of hepatic veins (HVs) draining into the inferior vena cava (IVC), and to classify the surgical techniques of piggy-back liver transplantation (PBLT) based on the anatomy of HVs which can reduce the occurrence of complications.

METHODS

PBLT was performed in 248 consecutive cases at our hospital from January 2004 to August 2011. The anatomy of recipients' HVs was determined when removing the native diseased livers. Both anatomy of HVs and short HVs draining into the IVC were recorded. These data were collected and analyzed.

RESULTS

We classified anatomic variations of HVs in the 248 livers into five types according to the way of drainage into the IVC: type I (trunk type of left and middle HVs), 142 (57.3%) patients; type II (trunk type of right and middle HVs), 54 (21.8%); type III (trunk type of left, middle and right HVs), 14 (5.6%); type IV (non-trunk type of left, middle and right HVs), of which, type IVa, 16 (6.5%), in the same horizontal plane; type IVb, 18 (7.3%), in different horizontal planes; and type V (segment type), 4 (1.6%). The patients whose HVs anatomy belonged to types I, II and III underwent classical piggy-back liver transplantation. Type IVa patients had classical PBLT via HV venoplasty prior to piggy-back anastomosis, while type IVb patients and type V patients could only have modified PBLT.

CONCLUSION

This study demonstrates that HVs can be classified according to the anatomy of their drainage into the IVC and we can use this classification to choose the best operative approach to PBLT.

Anatomy of the retrohepatic segment of the inferior vena cava and the ostia venae hepaticae with its clinical significance

PURPOSE

The present study was undertaken to provide morphological data regarding the retrohepatic segment of the inferior vena cava (RHIVC) and ostia venae hepaticae with an emphasis on the clinical significance of the observations made.

METHODS

This was an observational study conducted on 160 apparently healthy, randomly selected, cadaveric adult human livers fixed in 10% formalin. The distribution of the hepatic venous openings was studied by dividing the interior of the RHIVC into 16 quadrants. These openings were classified as large, medium, small and very small openings based on their diameter and were also classified as single/double/triple/quadruple according to the number of veins opening into them.

RESULTS

The median length of RHIVC was 7.3 cm (6.2-8.4) and was directed obliquely with respect to the vertical axis of the liver in 92.5% of cases. A total of 1,376 ostia venae hepaticae were observed, and the median number of openings per liver was 7 (5-9). The right hepatic vein had a single opening in 156 (97.5%) and the left and middle hepatic veins had a common opening in 144 (90%) cases. A longitudinal area on the anterior wall of the RHIVC, to the right side of the midline, was relatively avascular with 10.1% of the venous openings, of which 70% were single openings of the right dorsal vein having a small diameter (0.1-0.5 cm).

CONCLUSION

During liver hanging maneuver, rightward direction of the dissecting forceps would avoid injury to the caudate vein and allow access to the safe avascular space in the RHIVC.

Understanding the spectral Doppler waveform of the hepatic veins in health and disease

Duplex Doppler sonography is a fundamental component of the complete ultrasonographic examination of the liver. Accurate interpretation of the spectral Doppler tracing from the hepatic veins is valuable, as it reflects important cardiac and hepatic physiology. Normally, there are four phases: A, S, V, and D; the S and D waves indicate flow in the antegrade direction toward the heart. In hepatic and cardiac disease, these normal waves may be absent, a finding indicative of flow in a nonphysiologic manner. In addition, transient patient factors such as phase of the respiratory cycle may influence the appearance of the spectral tracing. Familiarity with the normal and abnormal spectral Doppler waveforms from the hepatic veins and knowledge of their respective physiology and pathophysiology provide valuable insights. Systematic analysis of the direction, regularity, and phasicity of the spectral tracing and the ratio of the amplitudes of the S and D waves allows one to arrive at the correct differential diagnosis in most situations.

Anatomy of retrohepatic segment of inferior vena cava and termination of hepatic veins

BACKGROUND

Information on anatomy of intrahepatic inferior vena cava (IVC) and hepatic vein openings in it is limited.

METHODS

We studied the retrohepatic segment of IVC and hepatic vein openings in it in 69 livers obtained from cadavers. The retrohepatic portion of the IVC was opened posteriorly by a vertical cut, the exposed surface was divided into 12 quadrants and the position, size, and septation of ostia of hepatic veins and any accessory openings were charted; measurements were made using Vernier calipers.

RESULTS

The median length of the intrahepatic IVC was 5.7 (range 3.3-8.2) cm and its median diameter was 2.3 (range 1.5-3.0) cm. The superior (major) set of hepatic veins comprised of two veins (right and left-middle) in 45 (65%) cases, three veins (right, middle, and left) in 23 (33%) and four veins in one (2%) case. Median diameter of the right hepatic vein was 1.5 (range 0.8-2.7) cm and that of left hepatic vein was 1.2 (0.7-2.6) cm. Middle hepatic vein, when separate, had a median diameter of 1.1 (range 0.5-1.5) cm. The inferior (minor) set of hepatic veins had two to 16 (median 7) veins.

CONCLUSIONS

Our data provide information on number, size, position, and septation of hepatic vein openings into the IVC. This information may be useful to hepatologists, hepatic surgeons while planning segmental resection of the liver, and to radiologists planning diagnostic and interventional procedures on hepatic venous system.

Course of the hepatic inferior vena cava in a Kenyan population

The course of the hepatic inferior vena cava (HIVC) has a wide range of variations which are relevant in hepato-vascular surgery and liver transplantation. Eighty livers were studied for hepatic course and axial orientation of the HIVC. The HIVC was found to run in an incomplete tunnel in 43.8% of the cases (n = 35), complete tunnel in 32.5% of the cases (n = 26) while in the rest, it was contained in a shallow groove on the retrohepatic surface. It assumed an oblique course in relation to the longitudinal axis of the liver in 60% of the cases (n = 48). The findings of this study vary to a wide range from those reported previously, and call for extra caution during surgical operations involving the HIVC region.

The caudate processus hepatic vein: a boundary hepatic vein between the caudate lobe and the right liver

OBJECTIVE

This study was conducted to find the boundary vein indicating the intersegmental plane between the caudate lobe and the adjacent liver segments.

SUMMARY BACKGROUND DATA

Major hepatic veins of the human liver commonly run through the intersegmental plane and are widely used for the landmarks to define the boundary of both sides of liver segments. As the caudate lobe is a small independent unit of the liver separate from the right and left livers, the existence of the boundary hepatic vein to the adjacent liver segments has been expected.

METHODS

Fifty-four adult cadaveric livers were minutely dissected to elucidate the correlation between the portal vein branches and the hepatic veins on both the caudate lobe and the adjacent liver segments.

RESULTS

Among the hepatic veins of the caudate lobe, the caudate processus hepatic vein entering the inferior vena cava at hepatic hilum runs in the segmental plane between the caudate processus and the right liver. Three types of the caudate processus hepatic vein directly entering the inferior vena cava and 1 type of the exceptional hepatic vein that was the tributary of the right hepatic vein were observed. They drained the blood of the caudate processus and a part of the right liver, respectively.

CONCLUSIONS

The caudate processus hepatic vein is one of the candidates of the hepatic vein indicating the boundary between the caudate lobe and the adjacent liver segments. New procedures will be developed on the liver surgeries by acquiring the anatomic features of this vein.

Anatomical Basis of Liver Hanging Maneuver: A Clinical and Anatomical in Vivo Study

Liver Hanging Maneuver (LHM) provides better exposure of the deeper section plane together with Inferior Vena Cava (IVC) protection during right hepatectomies without primary liver mobilization. This study assessed the feasibility and complication rates of LHM focusing on the anatomical distribution of the accessory hepatic veins in the retrohepatic portion of the IVC. From January 2002 to December 2005, LHM was planned in 49 consecutive major hepatectomies. The IVC retrohepatic portion was studied during the anhepatic phase in 17 liver transplantations with IVC preservation. The diameter and location of the vein openings were recorded after IVC division into nine portions. LHM was achieved in 47/49 patients (96%). Bleeding occurred in only one patient (2%) and did not entail procedure interruption. The anatomical study revealed a total of 86 veins present in 17 cases (5.18 ± 4 per patient) and classified them according to diameter (<3, 3 to 6, and >6 mm), as small (n = 40), medium (n = 29), and large (n = 17), respectively. Nine openings were found in the avascular channel for 6/17 (35%) patients (small n = 6, medium n = 3, large n = 0). LHM is a highly feasible procedure with minor bleeding risks due to the lower density and small diameter of short hepatic veins and caudate veins present in the avascular channel.

Liver hanging maneuver: an anatomic and clinical review

BACKGROUND

Liver hanging maneuver (LHM) allows to hang the liver during right hepatectomies without primary liver mobilization. The avascular plane used in this technique has been poorly described in the anatomical literature, and intraoperative bleeding because of hepatic vein injuries has been reported.

DATA SOURCES

Major clinical and anatomic articles focusing on the retrohepatic portion of the inferior vena cava (IVC) and the LHM were reviewed.

CONCLUSIONS

LHM is as an effective and safe method of guiding hepatic transection to the IVC during right hepatectomies with a feasibility rate up to 95% and minor bleeding in 0% to 6% of cases. According to small series and experts' opinions, LHM would improve parenchymal transection by reducing operative time and blood loss. The tape would ensure a linearly cut surface with IVC safer protection, better exposure, and hemostasis of the deeper plane. Limited remnant liver mobilization could reduce the risk for malignant dissemination and improve liver function. Hepatectomies for huge tumor with diaphragm adhesions could be facilitated.

Feasibility of bisegmentectomy 7-8 is independent of the presence of a large inferior right hepatic vein

BACKGROUND

Right superior liver resection or bisegmentectomy 7-8 is defined as the anatomical removal of segments 7 and 8 of the liver. According to recent reports, this type of resection requires the presence of a large accessory right inferior hepatic vein to drain the remaining segment 6. However, anatomic studies have shown that segment 6 has multiple veins presenting several anastomosis with the surrounding hepatic veins. Therefore, the maintenance of the veins from segment 5 that ultimately drain into the middle hepatic vein can be enough to assure venous drainage of both segments.

METHODS

Describe an alternative technique for bisegmentectomy 7-8 using intrahepatic glissonian access in patients with absence of a large inferior right hepatic vein.

RESULTS

The technique was successfully performed in four consecutive patients without immediate or long-term venous or venous related complications.

CONCLUSIONS

Bisegmentectomy 7-8 may increase resectability rate in patients with bilateral lesions and may also enhance the opportunity to perform repeated resections in cases of tumor recurrence. Our study confirms the anatomical assumption that bisegmentectomy 7-8 did not result in segmental outflow block even in the absence of a thick inferior right hepatic vein and therefore should be performed more often than reported so far. The absence of this vein should not be a straightforward indication for right hepatectomy in cases where a liver-sparing procedure such as bisegmentectomy 7-8 can be safely employed.

Hepatic surgical anatomy

The liver, the largest organ in the body, has been misunderstood at nearly all levels of organization, and there is a tendency to ignore details that do not fit the preconception. A complete presentation of the surgical anatomy of the liver includes the study of hepatic surfaces, margins, and fissures; the various classifications of lobes and segments; and the vasculature and lymphatics. A brief overview of the intrahepatic biliary tract is also presented.

Main accessory sulcus of the liver

It has been proposed that the superficial part of the portal fissures weakens the surface hepatic parenchyma, allowing the development of accessory sulci caused by diaphragmatic pressure. To evaluate the relationship of the sulci in the antero-superior surface of the right liver with the right portal fissure, macroscopic post mortem examination of 85 livers was carried out and radio-opaque resins were injected into the portal and hepatic venous systems to obtain vascular casts. After formalin fixation, the 85 livers also underwent CT and MR scans and 3D image elaboration. Diaphragmatic sulci were found in 32 cases. We studied the sulci located in the right liver, i.e., those that lay to the right of the line of Cantlie. They were found in 28 instances and in 16 cases they were multiple. In the livers with a single sulcus, it extended between the anterior and right surfaces of the right liver and showed a curved course downward and forward, toward the inferior margin. In the cases with multiple sulci, one sulcus always showed a course similar to that of the single sulci. The 28 sulci, with similar position and course, showed variable characteristics (mean length=7.6 +/- 2.7 cm, mean width=0.8 +/- 0.7 cm, mean depth=1.4 +/- 0.8 cm). Both radiological images and corrosion casts showed a correspondence between these sulci and the right hepatic vein and the right portal fissure in 71% of cases. These sulci may represent the variable expression (cranial, intermediate, or caudal portions) of a potential sulcus, the main accessory sulcus (MAS), that develops along a theoretically predictable course corresponding to the superficial part of the right portal fissure. The high prevalence of location of the MAS at the level of the upper part of the right portal fissure can be ascribed to the presence at this level of the watershed between the roots of the tributaries of the hepatic veins coming from segments VIII and VII, draining respectively into the middle and right hepatic veins. Thus, the coexistence of the two portal and hepatic venous boundaries may represent a further predisposition to the effects of diaphragmatic pressure. The MAS may represent a marking for the right portal fissure, and hence a superficial reference for the deep course of the right hepatic vein.

The caudate lobe of the liver: implications of embryology and anatomy for surgery

The anatomy of the caudate lobe has technical and possibly oncologic implications for surgeons. The complex anatomy of the lobe is clarified by embryologic and anatomic analysis. This posterior sector is embryonically and anatomically independent of the right and left liver and the main portal fissure. The caudate lobe represents the only part of the liver that is in contact with the vena cava, except at the entrance of the main hepatic veins into the vena cava, and provides an anastomosis between the hepatic veins and vena cava. The entire caudate lobe is a single anatomic segment that is defined by the presence of portal venous and hepatic arterial branches, which supply the lobe, draining biliary ducts, and hepatic veins. Because no separate veins, arteries, or ducts can be defined for the right paracaval portion of the posterior liver and because pedicles cross the proposed division between the right and left caudate, the concept of segment IX is abandoned. The significance of caudate anatomy is reflected in the increase in the frequency and safety of major hepatic resection for primary and metastatic tumors in the liver. Right hepatic lobectomy routinely involves resection of the right portion of the caudate lobe (C. Couinaud, unpublished data, 1999). In the case of hilar bile duct cancer, which may extend into the dorsal ducts (especially the right lateral duct), partial or total caudate lobectomy is often necessary for complete extirpation of the tumor. Isolated caudate lobectomy can be performed for hepatocellular carcinoma that arises in the caudate lobe or for other tumors that arise in the lobe. The caudate lobe can be resected as part of the donor liver in preparation for a living related donor transplantation. Knowledge of the surgical anatomy of the caudate lobe is an essential part of the repertoire for surgeons who perform liver transplants or treat hepatobiliary cancer.