The history of liver surgery is a tale of progressive resolution of issues presenting one after another from ancient times to the present days when dealing with liver ailments. The perfect knowledge of human liver anatomy and physiology and the development of a proper liver resective surgery require time and huge efforts and, mostly, the study and research of giants of their own times, whose names are forever associated with anatomical landmarks, thorough descriptions, and surgical approaches. The control of parenchymal bleeding after trauma and during resection is the second issue that surgeons have to resolve. A good knowledge of intra and extrahepatic vascular anatomy is a necessary condition to develop techniques of vascular control, paving the way to liver transplantation. Last but not least, the issue of residual liver function after resection requires advanced techniques of volume redistribution through redirection of blood inflow. These are the same problems any young surgeon would face when approaching liver surgery for the first time. Therefore, obtaining a wide picture of historical evolution of liver surgery could be a great starting point to serve as an example and a guide.

To investigate the independent risk factors for the first recurrence after endovascular management in patients with Budd-Chiari syndrome (BCS), and to establish a prediction model for predicting recurrence in target patients.

BCS patients who underwent endovascular treatment in the Affiliated Hospital of Xuzhou Medical University from January 2010 to December 2015 were retrospectively examined, with their clinical, laboratory test, and imaging data collected and analyzed. Independent risk factors for recurrence were identified, and a prediction model was established and validated.

A total of 450 patients met the filtering criteria, and 102 recurred during the follow-up. The median follow-up time was 87 months, ranging from 1 to 137 months. The 1-, 3-, 5- and 10-year cumulative recurrence rate was 9.11% (6.41-11.73%), 17.35% (13.77-20.78%), 20.10% (16.30-23.72%), and 23.06% (18.86-27.04%), respectively. Liver cirrhosis, ascites, thrombosis, and all the main intrahepatic drainage veins obstructed (obstructed HV + AHV) are independent risk factors, while age is an independent protective factor. The prediction model was named MRBET. Based on the model, the risk score of each patient equals (-0.385981 * Age/10) + (0.0404184 * PT) + (0.0943423 * CRE/10) + (0.0157053 * LDH/10) + (0.592179 * LC) + (0.896034 * Ascites) + (0.691346 * Thrombosis) + (0.886741 * obstructed HV + AHV), and those in the high-risk group (risk score ≥ 1.57) were more likely to recur than those in the low-risk group (HR = 6.911, p < 0.001). The MRBET model is also available as a web tool at https://mrbet.shinyapps.io/dynnomapp .

Liver cirrhosis, ascites, thrombosis, and obstructed HV + AHV are independent risk factors for the first recurrence; age is an independent protective factor. The prediction model can effectively and conveniently predict the risk of recurrence and screen out patients at a high recurrence risk.

Knowledge about the connective-tissue framework of the liver is not systematized, the terminology is inconsistent and some perspectives on the construction of the hepatic matrix components are contradictory. In addition, until the last two decades of the 20th century, the connective-tissue sheaths of the portal tracts and the hepatic veins were considered to be independent from each other in the liver and that they do not make contact with each other. The results of the research carried out by Professor Shalva Toidze and his colleagues started in the 1970s in the Department of Operative Surgery and Topographic Anatomy at the Tbilisi State Medical Institute have changed this perception. In particular, Chanukvadze I showed that in some regions where they intersect with each other, the connective tissue sheaths of the large portal complexes and hepatic veins fuse. The areas of such fusion are called porta-caval fibrous connections (PCFCs). This opinion review aims to promote a systematic understanding of the hepatic connective-tissue skeleton and to demonstrate the hitherto underappreciated PCFC as a genuine structure with high biological and clinical significance. The components of the liver connective-tissue framework - the capsules, plates, sheaths, covers - are described, and their intercommunication is discussed. The analysis of the essence of the PCFC and a description of its various forms are provided. It is also mentioned that analogs of different forms of PCFC are found in different mammals.

Although the Couinaud classification of liver segments has been challenged by several studies, whether the cranio-caudal boundaries can be delineated in the right liver has not yet been assessed. This study scrutinized the third-order branching pattern of the portal vein in the right liver with attention to the validity of cranio-caudal segmentation.

Three-dimensional reconstruction of the portal vein and hepatic vein, using non-contrast-enhanced magnetic resonance imaging was performed in 50 healthy participants.

In the right paramedian sector, the portal vein ramified into 2 thick P8s (P8vent and P8dor) in all the participants. Additional thick P8s that ran laterally and/or medially (P8lat and/or P8med) were observed in 18 (32%) participants. In contrast, multiple thin P5s, ranging in number from 2 to 6 (median, 4), branched from the right paramedian trunk, the right portal trunk, and/or even from P8s. In the right lateral sector, an arch-like type in which multiple P6s ramified from a single thick P7 was observed in 26 (52%) participants. A bifurcation type composed of a single P7 and a single P6 was observed in 23 (46%) participants, and a trifurcation type was observed in 1 participant.

No clear cranio-caudal intersegmental plane could be delineated in the right liver in most of the participants. The resection of a whole Couinaud segment in the right liver should not be regarded as a systematic, anatomic resection from an oncologic viewpoint. In contrast, detailed information on the third-order portal vein ramification pattern is likely to be helpful when performing smaller anatomic resections.

Couinaud based his well-known subdivision of the liver into (surgical) segments on the branching order of portal veins and the location of hepatic veins. However, both segment boundaries and number remain controversial due to an incomplete understanding of the role of liver lobes and vascular physiology on hepatic venous development. Human embryonic livers (5-10 weeks of development) were visualized with Amira 3D-reconstruction and Cinema 4D-remodeling software. Starting at 5 weeks, the portal and umbilical veins sprouted portal-vein branches that, at 6.5 weeks, had been pruned to 3 main branches in the right hemi-liver, whereas all (>10) persisted in the left hemi-liver. The asymmetric branching pattern of the umbilical vein resembled that of a "distributing" vessel, whereas the more symmetric branching of the portal trunk resembled a "delivering" vessel. At 6 weeks, 3-4 main hepatic-vein outlets drained into the inferior caval vein, of which that draining the caudate lobe formed the intrahepatic portion of the caval vein. More peripherally, 5-6 major tributaries drained both dorsolateral regions and the left and right ventromedial regions, implying a "crypto-lobar" distribution. Lobar boundaries, even in non-lobated human livers, and functional vascular requirements account for the predictable topography and branching pattern of the liver veins, respectively.

Worldwide, compartmentalization of the human liver into portal venous territories today follows the eight-segments scheme credited to Couinaud. However, there are increasing reports of anatomical, radiological and surgical observations that contradict this concept. This paper presents a viewpoint that enhances understanding of these inconsistencies and can serve as a basis for customized liver interventions. Clin. Anat. 30:974-977, 2017. © 2017 Wiley Periodicals, Inc.

BACKGROUND The laboratory rat is one of the most popular experimental models for the experimental surgery of the liver. The objective of this study was to investigate the morphometric parameters, physiological data, differences in configuration of liver lobes, biliary system, and vasculature (arteries, veins, and lymphatic vessels) of the liver in laboratory rats. In addition, this study supports the anatomic literature and identified similarities and differences with human and other mammals. MATERIAL AND METHODS Forty laboratory rats were dissected to prepare corrosion casts of vascular system specimens (n=20), determine the lymph vessels and lymph nodes (n=10), and for macroscopic anatomical dissection (n=10) of the rat liver. The results are listed in percentages. The anatomical nomenclature of the liver morphology, its arteries, veins, lymph nodes, and lymphatic vessels are in accordance with Nomina Anatomica Veterinaria. RESULTS We found many variations in origin, direction, and division of the arterial, venous, and lymphatic systems in rat livers, and found differences in morphometric parameters compared to results reported by other authors. The portal vein was formed by 4 tributaries in 23%, by 3 branches in 64%, and by 2 tributaries in 13%. The liver lymph was drained to the 2 different lymph nodes. The nomenclature and morphological characteristics of the rat liver vary among authors. CONCLUSIONS Our results may be useful for the planing of experimental surgery and for cooperation with other investigation methods to help fight liver diseases in human populations.

To compare 3D liver acceleration volume acquisition (LAVA) and digital subtraction angiography (DSA) for evaluating the presence of accessory hepatic veins (AHV) in Budd-Chiari syndrome (BCS).

This was a retrospective study in 228 patients with BCS who underwent 3.0T magnetic resonance imaging (MRI) with the 3D LAVA sequence. Two reviewers noted AHV: openings located in the inferior vena cava (IVC), caliber, and the angle of entering into the IVC. MRI results were compared to DSA. Kappa statistics were calculated to quantify intrareader variability in detecting AHVs.

On MRI, 63 patients demonstrated no AHV on LAVA images, 70 had one AHV, 62 had two AHVs, 26 patients had three AHVs, six patients had four AHVs, and one patient had five AHVs (P < 0.05 vs. DSA). The mean caliber of the AHVs was 8.3 ± 4.0 mm compared to 9.9 ± 3.2 for DSA (P < 0.001). Among the 301 AHVs, there were 140 with acute angles (46.5%), 71 with right angles (23.6%), and 90 with obtuse angles (29.8%). The prevalence of AHVs on DSA was 54.8% (125/228), while MRI demonstrated 301 AHVs in 165 patients, for a prevalence of 72.4% (165/228) compared to 54.8% for DSA (P = 0.001). The two methods were concordant in only 116/228 (50.9%) patients. The kappa coefficient demonstrated good intrareader consistency for all documented MRI findings of AHVs (κ = 0.626 for caliber and κ = 0.65 for angles).

More AHVs were visible on MRI LAVA sequences than on conventional DSA.

4 J. Magn. Reson. Imaging 2017;45:401-409.

To evaluate the type of venous involvement in Chinese Budd-Chiari syndrome (BCS) patients and the relative diagnostic accuracy of the different imaging modalities.

Using digital subtraction angiography (DSA) as a reference standard, color Doppler ultrasound (CDUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA) were performed on 338 patients with BCS. We analyzed the course of the main and any accessory hepatic veins (HVs) and the inferior vena cava (IVC) to assess the etiology of obstructed segments and diagnostic accuracy of CDUS, CTA and MRA.

Among the 338 cases, there were 8 cases (2.4%) of isolated IVC membranous obstruction, 45 cases (13.3%) of isolated HV occlusion, and 285 cases (84.3%) with both IVC membranous obstruction and HV occlusion. Comparing with DSA, CDUS, CTA had a diagnostic accuracy of 89.3% and 80.2% in detecting BCS, and 83.4% of cases correctly correlated by MRA.

In Henan Province, most patients with BCS have complex lesions combining IVC and HV involvement. The combination of CDUS and CTA or MRI is useful for diagnosis of BCS and guiding therapy.

The impact of hepatic venous anatomic variations on hepatic resection and transplantation is the least understood aspect of liver surgery.

A prospective three-dimensional computed tomography study was undertaken on 200 consecutive subjects with normal livers to determine the prevalence of surgically significant hepatic venous anatomic variations.

The prevailing pattern of the three hepatic veins in these subjects was a right hepatic vein (RHV) and a common trunk for the middle (MHV) and left (LHV) hepatic veins (122/200, 61%). The remaining patients had the RHV, MHV, and LHV draining independently into the inferior vena cava (IVC). In 39% of patients, the RHV was small and was compensated by a large right inferior hepatic vein (21.0%), an accessory RHV (8.5%) or a well-developed MHV (6.5%). A segment 4 vein was seen in 51.5% of patients. This segment 4 vein joined the LHV (26%), the MHV (17.5%), or the IVC (8%). An umbilical vein and a segment 4 vein were seen in 3.5% of patients. These two veins joined either the LHV (2.0%) or the MHV (1.5%).

Knowing the variations of hepatic veins before surgery is useful during both partial hepatectomy and donor operations for living related liver transplantation.

An increasing number of surgical and radiological observations call Couinaud's concept of eight liver segments into question and such inconsistencies are commonly explained with anatomical variations. This paper was intended to demonstrate that, beyond variability, another anatomical principle may allow to understand supposedly differing concepts on liver segmentation.

The study was performed on 25 portal vein casts scanned by helical CT. The branches of the right and left portal vein and their corresponding territories were determined both anatomically and mathematically (MEVIS LiverAnalyzer, MEVISLab).

The number of branches coming-off the right and left portal vein was never 8, but many more (mean number 20, range 9-44). Different combinations of these branches and their respective territories, carried out in this study, yielded larger entities and supposedly contradictory subdivisions (including Couinaud's eight segments), without calling upon anatomical variability.

We suggest the human liver to be considered as corresponding to 1 portal venous territory at the level of the portal vein, to 2 territories at the level of the right and left branch of the portal vein, and to 20 at the level of the rami of the right and left branch. This "1-2-20-concept" is a rationale for reconciling apparent discrepancies with the eight-segment concept. On a pragmatic level, in cases in which imaging or surgical observations do not fit with Couinaud's scheme, we propose clinicians not to autonomically conclude to the presence of an anatomical variation, but to become aware of the presence of an average of 20 (and not 8) second-order portal venous territories within the human liver.

To evaluate the distribution and clinical value of accessory hepatic veins (AHVs), we investigated the number and caliber of the AHVs and the angles between the shafts of AHVs and inferior caval vein. We analyzed the anatomical dissections, serial transverse and coronal sections (0.1-0.2 mm) of a frozen liver, and the ultrasonographical and enhanced CT images of healthy patients. We found that: (1) Most of the angles between the AHVs and inferior caval veins on the thin sections (78%) and liver dissections (72%) were acute (P < 0.01), while the AHVs with right angles had significantly larger average calibers (P < 0.05). However, on the contrary, most of the angles between the AHVs and inferior caval veins were right angles as observed in ultrasonography (89%) and spiral CT images (83%) (P < 0.01). The angle parameters appear to be more selective when displaying the AHVs on ultrasonography and spiral CT images. (2) The presentation rates of the AHVs in ultrasonic and spiral CT images were much lower than those of the anatomical dissections (P < 0.01). (3) There were no apparent differences in displaying right inferior hepatic veins between ultrasonography and spiral CT (P > 0.05). However, the presentation rate of small AHVs was much lower in spiral CT images (P < 0.05). (4) The ultrasonographical and spiral CT scans provide effective reference for the diagnosis of Budd-child syndrome, hepatectomy, especially liver hanging maneuver.

Split liver transplantation and living donor liver transplantation (LDLT) commonly use a right liver graft without the middle hepatic vein (MHV). Although tributaries of the MHV are not reconstructed in the majority of cases, the alterations of the microcirculation and its regional functions remain unknown. We addressed these issues by assessing liver tissue indocyanine green (ICG) uptake with near-infrared spectroscopy (NIRS) in 21 donors. After graft procurement, visual inspection (before and after hepatic arterial clamping) and Doppler examination of the veno-occlusive region were performed. Bolus ICG (100 microg/kg) was then administered intravenously. Blood ICG at the finger tip was measured with pulse dye densitometry, whereas the liver ICG concentrations in the veno-occlusive and non-veno-occlusive regions were simultaneously measured for 15 minutes by NIRS. We estimated the hepatic ICG uptake rate constants in the veno-occlusive region (Ku-oc) and non-veno-occlusive region (Ku-non). Changes in sinusoidal perfusion in the veno-occlusive region were expressed by the ratio of Ku-oc to Ku-non (Roc/non). The median value of Roc/non was 0.47, although it ranged from 0.13 to 0.94. Roc/non was related to the extent of liver surface discoloration before and after hepatic arterial clamping (P = 0.03 and 0.01, respectively). In conclusion, sinusoidal perfusion was impaired in the veno-occlusive regions of living donor livers, but the magnitude of the effect varied greatly. Measurement of hepatic ICG uptake by NIRS could become a valuable tool for assessing the indication for venous reconstruction in LDLT and/or split donor liver transplantation.

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

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.

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.

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.

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.

The fetal liver is located at the crossroads of the umbilical venous circulation. Anatomically, the ductus venosus (DV) and the intrahepatic branches of the portal vein are arranged in parallel. The actual DV shunting rate, i.e. the percentage of umbilical blood flow entering the DV measured by Doppler velocimetry, seems to be lower than that estimated using radioactively-labeled microspheres. In human fetuses the DV shunting rate is about 20-30%. Increases in the DV shunting rate are a general adaptational mechanism to fetal distress. Hypoxia results in a significant increase in the DV shunting rate, most probably in order to ensure an adequate supply of oxygen and glucose to vitally important organs such as the brain and heart. The mechanism of blood flow redistribution between the fetal liver and the DV is still a matter of debate. The isthmic portion of the DV contains less smooth muscle tissue than the intrahepatic branches of the portal vein, which in vitro react more forcefully in response to catecholamines than the DV. In growth-restricted human fetuses DV shunting is increased and the umbilical blood supply to the fetal liver is reduced. The long-term reduction of the hepatic blood supply may be involved in fetal growth restriction. The occlusion of the DV leads to a significant increase in cell proliferation in fetal skeletal muscle, heart, kidneys and liver, and possibly to an increase in insulin-like growth factor (IGF)-I and -II mRNA expression in the fetal liver. These findings hint at the possible role of the perfusion of the fetal liver in the control of the growth process. The quantification of DV shunting by Doppler velocimetry may improve the early recognition of fetal compromise in prenatal medicine. In this Review we summarize the published data on the anatomical structure and histology of the DV, the mechanisms of regulation of DV shunting, its role in fetal survival and growth and the possible use of the measurement of DV shunting in clinical practice.

We aimed to clarify the morphogenesis of an anomalous ligamentum venosum terminating in the trunk of the superior left hepatic vein, because the ligamentum venosum ordinarily terminates into the root of the left hepatic vein or directly into the inferior vena cava.

We examined an anomalous ligamentum venosum found in the cadaveric liver of an 84-year-old Japanese woman.

The ligamentum venosum in this liver was not found in the usual course, the fissure for the ligamentum venosum. It lay on the posterior surface of the liver, connecting the left branch of the portal vein and the trunk of a small left hepatic vein. The small left hepatic vein draining the cranio-dorsal part of the lateral segment of the liver was revealed to be a superior left hepatic vein. This type of anomaly was found only in this 1 liver, among 125 cadaveric livers that were dissected.

Taking previous reports into consideration, the morphogenesis of the anomalous ligamentum venosum in the present case may be explained as being due to the persistence of the right half of the subdiaphragmatic anastomosis, which receives the blood from the ductus venosus in the embryonal period.

To clarify anatomical distribution of Fasciola infection, the vascular and ductal architectures of the liver were studied by means of corrosion cast technique using synthetic resin. The arteria hepatica propria (AP) passes as the arteria gastroduodenalis (AG); AP becomes the left trunk after the porta hepatis; AP passes on the right side of vena porta communis (VPC) and projects AG while curving in a U-shape below the portal vein. Hepatic veins located between the vena hepatica media (HM) and vena hepatica dextra (HD) varied widely among specimens and were irregular, including the vena hepatica dorso-lateralis sinistra (Hds), vena hepatica dorso-lateralis dextra (Hdd), vena hepatica lobi caudati (Hlc), venae hepaticae processus caudati (Hpc), venae hepaticae processus papillaris (Hpp), and the hepatic vein to the dorsal intermediate part, which directly or indirectly drained into the vena cava caudalis. The courses of the bovine hepatic veins were markedly diverse, and anastomoses between vena hepatica sinistra (HS) and Hds were observed in about a half of the livers. The portal vein entered the liver as VPC slightly above the centre of the right lobe on the visceral surface. The intermediate or transverse part [pars transversa trunci sinistri (PTS)] of truncus sinister (TS), which extends from the entry of the portal vein into the left lobe of the liver, was slightly arched downward [pars umbilicalis trunci sinistri (PUS)]. The portal vein further arched from the distal end of TS to the umbilical vein and ran towards the inter-lobar incision between the left lobe and quadrate lobe. Based on these branches, hepatic segments were determined as 13 or 14 areas. A total of 15 bile ducts were derived from various lobes. The hepatic duct was about 2.6-6 cm long from the confluence of the right and left hepatic ducts to the division of the cystic duct and the common hepatic duct.

Three main hepatic veins: right, middle and left are constant, but there is a variable number of retrohepatic vessels called accessory or minor hepatic veins. The most important of them are veins reffered to as middle right hepatic vein (MRHV) draining segment VII and inferior right hepatic vein (IRHV) draining segment VI. The incidence of large MRHV and IRHV reaching or exceeding a caliber of 5mm, their arrangement in the liver and drainage territories were investigated in our collection of 142 injection-corrosion specimens of the liver. In 1/5 of the cases with large IRHV this vein drains small part of segment VI, sometimes its insignificant marginal part so it couldn't be used for segment VI preservation when it is necessary. A precise knowledge of the vein anatomy of right posterior sector of the liver and its vein drainage territories is very important during complex dissections of the retrohepatic areas, resections and preservation liver parenchima.

Using drip-infusion cholangiography-computed tomography (DIC-CT), we successfully identified the bile ducts draining the caudate lobe in 138 of 179 consecutive patients with extrahepatic cholelithiasis (179 ducts from Spiegel's lobe and 154 from the paracaval portion; 1-5 ducts per patient). The dorsal subsegmental duct of S8 (B8c) was often identified and could be discriminated from the paracaval caudate ducts, thus acting as a landmark for the right margin of the caudate lobe. Notably, in more than one-third of the 138 patients, at least one of the Spiegel's lobe ducts drained into the right hepatic duct or its branches (30.2% of the 179 ducts overall; all ducts joined branches of the right lobe in 25 patients). Similarly, 34.4% of the 154 paracaval caudate lobe ducts drained into the left hepatic duct or its branches. These "anatomical left/right dissociations" between the drainage territory and route were much more frequent than previously reported. Our results confirm the effectiveness of DIC-CT as a classical, noninvasive method for presurgical evaluation of the biliary system, but they also suggest that anatomical partial resection of the dorsal liver in patients with hilar cholangioma is often impossible because of contralateral biliary drainage.

In living-donor and split-liver transplantations using a hemi-liver graft, it is practically impossible to maintain complete venous drainage in both the right and left livers, because the middle hepatic vein can be preserved only on the unilateral side. However, it is not clear whether partial venous disturbances affect postoperative liver volume regeneration.

Living donors who underwent left-sided hepatectomy preserving the middle hepatic vein (group A, n=40) or left hepatectomy with middle hepatic vein resection (group B, n=37) were reviewed. Volume regeneration of the remnant right paramedian (segments V + VIII) and lateral (segments VI + VII) sectors and overall liver volume was assessed at 3 postoperative months by computed tomography.

In group A, both sectors showed a proportional increase by 21.7% (P=0.991), whereas in group B the rate of increase of the right paramedian sector was less than that of the right lateral sector (13.3% vs. 36.5%, P<0.001). Comparisons of rate of increase for each sector between the groups indicated that interruption of the middle hepatic venous drainage impaired enlargement of the right paramedian sector and induced a compensatory hypertrophy of the right lateral sector. Overall liver mass restoration rate in group B was inferior to that in group A (78.9% vs. 85.0%, P=0.001).

Split livers with partial outflow disturbances are associated with latent disadvantages in postoperative liver volume regeneration even if venous congestion is not evident. These results suggest a problem of regenerative capacity of right liver grafts.

Liver resection of segments VII and/or VIII sometimes requires segmental resection of the right hepatic vein in patients with liver tumours invading or located close to the hepatic vein. In this situation, hepatic vein reconstruction is thought to have an important role in the postoperative function of segment VI. This study investigated whether preoperative embolization of the major hepatic vein could obviate the need for hepatic vein reconstruction after cranial partial resection of the liver including the major hepatic vein trunk in a preclinical model.

Sixteen beagles were divided into two groups of eight: control group (hepatectomy alone) and hepatic venous embolization (HVE) group (hepatectomy after HVE). HVE was performed 2 weeks before hepatectomy. All dogs underwent resection of the cranial third of the left lateral liver lobe together with the major trunk of the left hepatic vein. Following hepatectomy, survival, histological features, portal venous pressure and serum aspartate aminotransferase (AST) levels were determined.

Six control animals and seven in the HVE group were alive 1 week after hepatectomy. Immediately after hepatectomy, portal venous pressure was significantly higher in the control group compared with the HVE group (mean(s.d.) 14.0(1.1) versus 8.1(1.0) mmHg; P < 0.01). Histological examination of the remnant left lateral lobe demonstrated patchy parenchymal haemorrhage in the control group and normal parenchymal architecture in the HVE group. Peak AST levels were observed on day 1 in both groups and were significantly higher in the control group (mean(s.d.) 182(42) versus 67(40) units/l; P < 0.01).

In this model, preoperative HVE facilitated interlobar venous collateral formation and minimized the untoward effects of segmental hepatic vein resection. This procedure may obviate the need for hepatic vein reconstruction after cranial partial liver resection including the major hepatic vein.

A detailed description of the distribution and drainage pattern of the minor hepatic veins is presented in this paper. A classification based on the segmentation of the liver divides these veins into four main groups: 1) veins of Segment I which includes the veins of the caudate lobe and the veins of the caudate process; 2) veins of Segment VI; 3) veins of Segment VII; and 4) veins of Segment IX. A knowledge of the anatomy of the minor hepatic veins becomes more clinically valuable as the number of complex dissections of the retrohepatic areas, hepatectomies. and hepatic transplantations grow.

The configuration of the right portion of the caudate lobe (CL), and especially the exact location of its right margin, remains obscure. This study aimed to identify this right margin according to reliable landmarks suitable for use during clinical examinations and surgery: (1) the bifurcation of the right portal vein, (2) the end of the right hepatic vein, and (3) the notch on the gallbladder fossa. The plane defined by these three landmarks is called the right paracaval plane. Dissection of 55 livers demonstrated that the entire CL was usually contained within the left half of the specimen after cutting along the right paracaval plane (Type A: 65.4%, 36/55). However, its right portion sometimes extended beyond this plane into the right half of the liver (34.6%, 19/55), forming one or two islands when viewed from the paracaval plane (Types B and C). We found two separate marginal configurations among the 19 rightward extensions of the paracaval portion: a tree-like, deep protrusion (11/19) and a relatively smooth border (8/19). The present results suggest the existence of reliable landmarks that will allow a right-side limit for surgical resection of the CL to be established: (1) the right paracaval plane (60% reliability), (2) 10 mm to the right of the plane, including the terminal of the right hepatic vein (80% reliability), and (3) the widest margin, including the 30 mm to the right of the right paracaval plane, the right side running along the inferior vena cava, and the diaphragmatic surface around the end portions of the three main hepatic veins (100% reliability).

Endoscopic surgery, also called minimally invasive surgery, is presumed drastically to reduce postoperative morbidity and thus to offer both human and economic benefits. For the surgeon, however, this approach leads to a number of gestural challenges that require extensive training to be mastered. In order to replace experimentation on animals and patients, we developed a simulator for endoscopic surgery. To achieve this goal, a first step was to develop a working prototype, a "standard patient," on which the informatic and microengineering tools could be validated. We used the visible man dataset for this purpose. The external shape of the visible man's liver, his biliary passages, and his extrahepatic portal system turned out to be fully within the standard pattern of normal anatomy. Anatomic variations were observed in the intrahepatic right portal vein, the hepatic veins, and the arterial blood supply to the liver. Thus, the visible man dataset reveals itself to be well suited for the simulation of minimally invasive surgical operation such as endoscopic cholecystectomy.

This article examines the scientific, technical, and administrative barriers to splitting donor livers for use in two adults. The main scientific barrier is that cadaveric donor livers at their current level of postoperative function are not sufficiently large to support life in two adult recipients. However, glycogenation of livers from young donors may be a method to overcome this problem in the short term. The three technical obstacles to splitting the liver in the midplane are anatomic anomalies that complicate or prevent splitting, the means to detect these anomalies, and the surgical methods to accomplish the split. Anatomic anomalies affecting the biliary drainage and arterial supply of the liver are the most important limiting technical factors. Administrative accommodations in the current methods of organ allocation will be needed if split-liver transplantation in adults is to succeed. A nationwide view of organ allocation requires that the total number of lives saved by the procedure be the priority outcome nationally. If liver transplantation is viewed from this perspective, split-liver transplantation for adults would be a high priority, and incentives should be set to encourage it.

We describe the pattern of intrahepatic vessel ramification in the right posterior hepatic sector in a population of 197 adults. Each specimen was dissected from its visceral (inferior) surface in order to demonstrate variations in the distribution of the portal vein branches to the hepatic segments of the right lobe, especially to segments VI (S6) and VII (S7) as described by Couinaud. We also examine whether three hepatic veins, i.e., the right hepatic vein (RHV), middle hepatic vein (MHV), and the short hepatic vein (SHV), aid the identification of segmental portal branches in the lower posterior sector. Four major patterns of branching of the posterior sectorial trunk of the portal vein system are described. In group A (32.0%) a single posterior trunk formed an arch-like pattern sending multiple branches to S6 and S7 (P6 and P7). We named the multiple branches to the apparent S6 the inferoposterior portal branches. It was difficult to identify which of these branches were equivalent to P6. In group B (27.9%), the posterior sectorial trunk bifurcated to form P6 and P7. In most of the specimens in this group, therefore, we were able clearly to identify both S6 and S7 based on the portal vein system. In group C (6.6%), the trunk trifurcated to form P6, P7, and an intermediate branch, which supplied both segments or a gray zone between them. Group D (33.5%) included variations of the anterior segmental branches, and in specimens of this group, the anteromedial border of the sector was difficult to identify. Notably, the three-dimensional interdigitating topographical relationship of the hepatic veins and the portal branches was not evident in the lower posterior sector, since tributaries of the RHV and the portal branches followed similar courses and paralleled each other in the region and since the territory of the SHV was usually restricted to the superficial parenchyma near the inferior surface. In group A, tributaries of the RHV/SHV (>3 mm in diameter) passed between the inferoposterior portal branches in only 22.2%/14.3% of the specimens. Thus the hepatic veins often did not reveal which of the multiple inferoposterior branches was P6. Moreover, in the subset of Group B in which the segments were identified based on the portal vein ramification, tributaries of the RHV/SHV (>3 mm in diameter) showed the intersegmental interdigitating arrangement in only 32.0%/6.0% of the specimens. In addition, a thick tributary of the MHV, sometimes arising from S6, did not run along, but penetrated the S5/S6 border plane from the lateral to the medial side. Therefore, the three hepatic veins (RHV, SHV, MHV) often did not aid the identification of the liver segments in the region. Consequently, the less than ideal combinations of irregular configurations of the portal and hepatic venous systems suggest that the right posterior segments cannot be conclusively identified anatomically in 30-40% of cases. Other means of identification, such as the conventional proportional manner (the upper and lower halves of the posterior sector roughly correspond to S6 and S7) may be required.

The arrangement of muscle, collagen and elastic fibers was studied in the retro- and suprahepatic (subdiaphragmatic) portions of the inferior vena cava, the hepatic veins and their main affluents. Distinctive features of the longitudinal and transverse muscle bundles are described. In these portions of the vena cava, both bundle systems are clearly separate and any continuity was observed only at the entrances of the hepatic veins. A musculo-venulolymphatic complex was noted in spurs formed by the vascular junctions. The hepatic veins and their main affluents exhibit an elliptical contour in transverse section, which apparently results from cranial and caudal thickenings of the longitudinal muscle layer. Many of these bundles are in continuity with those of the transverse muscle layer. Terminal elastic tendons were rarely observed in connection with muscle fibers of the inferior vena cava and are not present in the hepatic veins and their main affluents. In terms of form and function, the relatively thin muscular layer has a dilating action on the hepatic venous system because of the external fixed insertion point of the muscle bundles. Such an arrangement and a "polar" disposition of the muscle bundles in the hepatic venous system may assists in "suction" of the blood toward the heart. A sphincteric control of the ostia by means of crossed muscular loops supported by venulo-lymphatic micropads is a possibility.

To delineate the relationship of the main portal vein bifurcation to the liver capsule, an anatomic study of the portal vein bifurcation was undertaken in 31 cadavers.

The portal bifurcation was characterized as intrahepatic, extrahepatic, or at the liver capsule (junctional). When the bifurcation was extrahepatic, the exposed portions of the right and left portal veins were measured.

The portal bifurcation was intrahepatic in eight cadavers (25.8%), at the liver capsule in eight cadavers (25.8%), and extrahepatic in 15 cadavers (48.4%). The maximum lengths of exposed extrahepatic right and left portal veins were 3.0 cm and 2.5 cm, respectively.

These findings suggest that for transjugular intrahepatic portosystemic shunt placement, a portal vein puncture site 3 cm from the portal bifurcation will be intrahepatic in most cases.

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.

Complete surgical resection represents the only treatment for malignant tumors of the liver which offers the chance of long-term tumor-free survival. From this oncological perspective the segment orientated approach appears to be a valuable supplement of traditional hepatic surgery. It minimizes incomplete tumour removal, and prevents a waste of non-involved hepatic tissue. This combination of optimum local radicality and maximum parenchyma preservation also reduces operative risk. Various modern diagnostic and surgical aids such as intraoperative ultrasound, liver transection using the ultrasonic aspirator, and control of bleeding by means of infrared coagulation or fibrin tissue adhesive, all do considerably support this individualized surgical approach. However, the practical application is essentially based on the intrahepatic vasculature and the thereby defined segmental anatomy. The sequence of the operative proceeding will be illustrated for different mono- and polysegmentectomies.

Hepatic venographies were performed selectively in 42 patients with hepatocarcinoma. The findings were evaluated from anterior and lateral views. Thirty-nine right hepatic v. could be identified and the existence of one branch as the first ramification was found in 36 cases (92.3%). The first branches of the right hepatic v. could be classified into veins (V7) running from segment VII and those (V8) running from segment VIII. A V7 was identified in 26 cases (72.8%) and a V8 was identified in 10 cases (27.8%). The vena hepatica dorsalis (V8) running from segment VIII was recognised in 10 cases. The middle and left hepatic v. were identified in 31 cases and 33 cases respectively. Two main types of middle vein (one with no principal branching and the other with branching) were found in 11 cases (37.9%) and 12 cases (41.4%) respectively. The first branch of the middle hepatic v. (V8) running from segment VIII was identified in 10 cases (32.3%). These results indicate that anatomical consideration of the hepatic v. in each patient is necessary when performing hepatic resection.

The anatomy of the liver of the human fetus was established on the basis of cadaveric techniques, but its study has been transformed by obstetric ultrasonography. This work is based on a personal study of the normal morphology of the liver of the human fetus and on a review of the current literature, particularly with regards to vascularization. The liver is the digestive organ whose rudiments appear earliest and which develops most rapidly. The development of the liver and its functional segmentation are determined by the oxygenated blood flow in the umbilical vein. The extent of each hepatic territory depends on the quantity of umbilical flow, which determines its development and ensures its function. The fetal liver occupies a very large proportion of the abdominal cavity. It is a vascular organ, closely moulded to the walls of the abdominal cavity and the viscera in contact with it. The left liver is a little more bulky than the right liver and is developed mainly transversely. The morphology of the normal fetal liver appears quite uniform. The intrahepatic umbilical vein and the venous axis prolonging it to the right have a remarkably constant arrangement, well demonstrated by ultrasonography. An assessment of the anatomic features of the afferent veins, the ductus venosus and the efferent veins gives some idea of the conditions of the intrahepatic venous circulation in the human fetus that remain to be demonstrated. At birth, ligature of the umbilical v. brings about a sudden change in the hepatic circulation, resulting in temporary morphologic and functional modifications in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Over a 24-year period, 411 partial hepatic resections were performed: 142 right or left trisegmentectomies, 158 lobectomies, 25 segmentectomies, and 86 local excisions. The operations were performed for benign lesions in 182 patients, for primary hepatic malignancies in 106, and for hepatic metastases in 123, including 90 from colorectal cancers. The 30-day (operative) mortality rate was 3.2%, and there were an additional six late deaths (1.5%) due to hepatic failure caused by the resection. The highest operative mortality rate (6.3%) resulted from the trisegmentectomies, but this merely reflected the extent of the disease being treated. A mortality rate of 8.5% for patients with primary hepatic malignancy was associated not only with the extensiveness of lesions, but also with cirrhosis in the remaining liver fragment. There was no mortality for 123 patients with metastatic disease, 100 patients with cavernous hemangioma, 22 with liver cell adenoma, 17 with focal nodular hyperplasia, 16 with congenital cystic disease, and five with hydatid cysts. Trauma, pre-existing iatrogenic injury, and cirrhosis were the only conditions that had lethal portent in patients with benign disease. Furthermore, patients with benign disease who survived operation had minimal liability from recurrence of their original disease and none from the resection per se. By contrast, tumor recurrence dominated the actuarial survival rates for cancer patients, which at 1 and 5 years were 68.5% and 31.9%, respectively, after resection for primary hepatic malignancy, and 84.2% and 29.5%, respectively, for hepatic metastases. In this report, the expanding role of partial hepatectomy in the treatment of liver disease was emphasized, as well as the need for considering, in some cases, the alternative of total hepatectomy and liver replacement.