Anatomy of the portal branches and the hepatic veins in the caudate lobe of the liver

The objective of this study was to analyze the caudate portal branches and their relationships with the hepatic caudate veins and propose a new nomenclature for the caudate branches based on their territory of distribution. We realized the fine dissection of the veins of the caudate lobe in 40 human livers fixed and preserved in formalin. In 15/40 (37.5%) cases there was a single branch to the caudate lobe. In 25/40 (62.5%) cases there was more than one branch, with a posterior caudate branch in 20/40 (50%) cases, an anterior caudate branch in 15/40 (37.5%) cases, a left caudate branch in 14/40 (35%) cases, and a right caudate branch in 8/40 (20%) cases. The most frequent combination detected (11/40, 27.5% of cases) was that of the posterior and anterior branches. The venous drainage of the caudate lobe and its papillary process was provided by the superior caudate hepatic vein in 23/40 (57.5%) cases, by the middle caudate vein in 35/40 (87.5%) cases (which was the only vein in 12/35 cases), and by the inferior caudate vein in 16/40 (40%) cases. In 11/40 (12.5%) cases there were accessory caudate veins, which emptied into the left and intermediate hepatic veins. The portal branches and the hepatic veins related to the caudate process were studied. In conclusion, the new nomenclature analyzes more precisely the distribution of the caudate portal branches.     

Retrograde portography of the right caudate lobe via the middle hepatic vein

Hepatobiliary resection with caudate lobectomy has been conducted in the surgical treatment of bile duct carcinoma of the hepatic hilus. However, insufficient attention has been paid to the anatomy of the right portion of the caudate lobe, and techniques to visualize the portal branches of the right caudate lobe (P1r) have not been reported. Contrast medium was injected into the dorso-caudal branches of the middle hepatic vein (MHV) and images were obtained by digital subtraction venography. Retrograde portography of the P1r was achieved in 64 (84%) out of 76 cases. The mean number of visualized branches was 2.1 (137 out of 64) and the P1r coursed beyond the trunk of the MHV in 36 (56%) out of the 64 cases. Contrast medium flowed into the right portal vein from 59 P1r branches in 32 cases and into the left portal vein in 20 cases. No complications were encountered. Retrograde portograms of the P1r may provide valuable information not previously available to surgeons operating on the caudate lobe.     

Human liver caudate lobe and liver segment

Recently, the caudate lobe has seemed to be the final target for aggresive cancer surgery of the liver. This lobe has five surfaces: the dorsal, left and hilar-free surfaces and the right and ventral-border planes. Surgeons have divided the caudate lobe into three parts: Spiegel’s lobe, which is called the ‘caudate lobe and papillary process’ by anatomists, the caudate process, viewed as almost the same entity by anatomists, and the paracaval portion corresponding to the dorsally located parenchyma in front of the inferior vena cava. All three parts are supplied by primary branches originating from the left and right portal veins, including the hilar bifurcation area. The hilar bifurcation branch often (50%) supplies the paracaval portion and it sometimes (29%) extends its territory to Spiegel’s lobe. It was postulated by Couinaud that the paracaval portion or the S9 is not defined by its supplying portal vein branch but by its ‘dorsal location’ in the liver. Couinaud’s caudate lobe or dorsal-liver concept caused, and still now causes, great logical confusion for surgeons. We attempt here to describe the margins of the lobe, border branches of the portal vein, the left/ right territorial border of the portal vein or Cantlie’s line and other topics closely relating to the surgery within these contexts. Finally, the caudate lobe as a liver segment will be discussed.     

肝尾状叶脉管构筑的应用解剖

应用55例成人肝剥离标本及45例胎儿、新生儿肝管道铸型,研究了肝尾状叶的鞘系及静脉回流。尾状叶有两个恒定的蒂、接受左、右侧鞘系的双重供应,以左侧为主;而尾状突主要由右后叶鞘系分布。15例肝铸型标本的尾状叶左、右侧动脉形成吻合弓。尾状叶动脉供应形式可分为三种,静脉可分为三型并直接汇入下腔静脉。由于血管吻合的存在,在病理状态下,尾状叶也应是沟通门一腔静脉的桥梁。     

尾状叶切除术应用解剖学研究

目的：为肝尾状叶切除术提供形态学理论基础。方法：选取37具成人离体尸肝标本，采用雕琢法和断层解剖观测肝尾状叶形态、毗邻，血管系统的来源、走行，肝后腔静脉前间隙。结果：尾状叶三管系统的来源，Spiegel叶多以左肝三管系统为主，而腔静脉旁叶多以右肝或分权处为主，三管系统中，以门静脉分支分布最为稳定，尾状叶静脉变异较大；三管系统在进入尾状叶时形成簇；尾状叶有前平面及肝后腔静脉前间隙；尾状叶Spiegel叶与腔静脉旁部存在较为明显的界线，其外部标志大致与其外切迹相当，腔静脉旁部与尾状突无明显的界线。结论：肝尾状叶位置特殊，毗邻关系复杂，三管系统进入尾状叶的位置比较恒定。尾状叶的手术切除术应首先确定边界，根据相应的解剖标志来选择手术方式及入路。     

Ramification pattern and topographical relationship between the portal and hepatic veins in the left anatomical lobe of the human liver.

Sixty-one human livers obtained from donated Japanese adult cadavers were dissected to reveal the ramification pattern of the portal and hepatic veins, and their topographical relationship in the left anatomical lobe. The segmental portal vein supplying S2 (P2) tended to form a single stem, whereas that of S3 (P3) was usually double. An intermediate branch between P2 and P3 was observed in 23.0% of livers. In spite of variation between livers, definite P2 and P3 were identified in 47 specimens. One tributary of the left hepatic vein (LHV) was usually present for drainage of S2, and two tributaries were present for S3 (sometimes also for S2 and/or S4). The latter two tributaries of the LHV and the two subsegmental branches of S3 showed three patterns of three-dimensional interdigitations. From these results, the portal vein system did not seem to have a two segmental composition (i.e., S2 and S3) in 23.0% of specimens, whereas the hepatic vein system did not have an intersegmental course in 23.4%. Thus, there were obvious limitations in using each system to determine the liver segment. Taking the overlapping cases into consideration, the left anatomical lobe of 41.0% of specimens did not seem to fit the definition of Couinaud's liver segment. In addition, four patterns of fissure vein (or scissural vein), > 5 mm in diameter at its terminal, were identified: (1) middle hepatic vein type (left median vein, 9.8%); (2) LHV type (left medial vein, 41.0%); (3) true fissure vein (3.3%); and (4) absent cases (45.9%). The former two types also suggested limitations of the hepatic vein system as an indicator of the segmental border.     

Origin and distribution of portal blood in the cat and the rabbit

The portal vein in the rabbit is formed by union of the gastrosplenic vein, which extends caudally and to the right, and the relatively larger and cranially directed mesenteric vein, formed from cranial and caudal mesenteric and caudal pancreaticoduodenal tributaries. The gastroduodenal vein, which receives blood from the distal pylorus, greater omentum, pancreas and duodenum, joins the rabbit portal vein opposite the branch to the caudate lobe. In the cat, the portal vein is formed by the junction of the gastrosplenic, which is directed transversely or cranially, and the mesenteric, and receives two main tributaries: the gastroduodenal, which is the main vein from the stomach, and the cranial pancreaticoduodenal. When ¹³¹I-rose bengal was injected into the spleen of conscious standing cats and entered the portal vein in the gastrosplenic, it was distributed preferentially to the right branch and the left lateral ramus of the left branch. In the rabbit, there was no evidence for preferential distribution of splenic blood, but blood from the cranial mesenteric vein was distributed preferentially to the right and caudate branches and that from the caudal mesenteric to the caudate. This distribution was affected by the entry of blood in the gastrosplenic vein. Although statistically significant differences did occur in the intrahepatic distribution of blood derived from the portal tributaries, the absolute differences were small.     

肝尾状叶及其血管的断层解剖学研究

为给肝尾状叶疾病的影像诊断和外科手术提供形态学依据，本文利用成人腹部连续横断层标本22例、矢状断层标本14例和冠状断层标本5例研究了肝尾状叶及其血管的断层解剖。肝尾状叶有5面，在外形上可分为固有肝尾状叶(Spigelian叶)、腔静脉旁部和尾状突三部分。固有肝尾状叶，在横断面上，14例(63．6％)伸出腔静脉后突，11例(50％)出现孤立乳头突现象；在矢状断面上，4例(28．6％)下端出现分叉。在15例(68．2％)横断层和12例(85．7％)矢状断层标本上，可见肝尾状叶鞘系，主要出现于肝门静脉左支横部层面。在断层标本上，可见1～3支尾状叶静脉，大部分汇入下腔静脉肝后段的中、下份。粗大的肝右后下静脉分别见于10例(45.5％）横断层、4例(28.6％）矢状断层和l例冠状断层标本上。此外，文内还详细探讨了肝尾状叶在横、矢、冠状断面上的识别、毗邻及其在影像诊断和在肝切除术中的意义。     

Applied anatomy of small branches of the portal vein in transverse groove of hepatic hilum

Purpose

The objective of this study was to provide the morphological details on small branches of the portal vein in transverse groove of hepatic hilum.

Methods

According to the surgery significance, the small branches of portal vein in transverse groove of hepatic hilum were named as “Short hepatic portal veins (SHPVs)”. SHPVs were minutely dissected in 30 adult cadaveric livers. The number, diameter, length, origin points, and entering liver sites of SHPVs were explored and measured.

Results

There were 181 SHPVs in 30 liver specimens, including 46 % (83/181) from the left portal vein, 31 % (56/181) from the bifurcation, and 23 % (42/181) from the right portal vein. At the entering liver sites of SHPVs, 22 % (40/181) supplied for segment IV, 9 % (17/181) for segment V, 4 % (7/181) for segment VI, 23 % (41/181) for segment VII, and 42 % (76/181) for segment I (caudate lobe). There were 6.0 ± 2.4 branches per liver specimen with range 3–12. The mean diameter of SHPVs was 2.25 ± 0.89 mm. The average length of SHPVs was 4.86 ± 2.12 mm.

Conclusions

SHPVs widely existed in each liver specimen. The detailed anatomical study of SHPVs could be useful to avoid damaging the short portal branches during hepatic operations, such as isolated or combined caudate lobectomy.     

Absence of bifurcation of the portal vein

Background  Absence of the horizontal segment of the left portal vein (PV) or absence of bifurcation of the portal vein (ABPV) is extremely rare anomaly. The aim of this study was to study the extra-hepatic PV demonstrating the importance of its careful assessment for the purpose of split-liver transplantation. Method  Human cadaver livers (n = 60) were obtained from routine autopsies. The cutting plane of the liver consisted of a longitudinal section made immediately on the left of the supra-hepatic inferior vena cava through the gallbladder bed preserving the arterial, portal and biliary branches in order to obtain two viable grafts (right lobe—segments V, VI, VII, and VIII and left lobe—segments II, III, and IV) as defined by the main portal scissure. The PV was dissected out and recorded for application of the liver splitting. Results  The PV trunk has been divided into right and left branch in 50 (83.3%) cases. A trifurcation of the PV was found in 9 (15.2%) cases, 3 (5%) was a right anterior segmental PV arising from the left PV and 6 (10%) a right posterior segmental PV arising from the main PV. ABPV occurred in 1 (1.6%) case. Conclusion  Absence of bifurcation of the portal vein is a rare anatomic variation, the surgeon must be cautious and aware of the existence of this exceptional PV anomaly either pre or intra-operatively for the purpose of hepatectomies or even split-liver transplantation.     

兔肝脏及附属管道的应用解剖学研究

目的　对兔肝脏及其附属管道进行应用解剖学研究。 方法　对20只日本大耳兔分别进行活体和离体形态学观察,制作门静脉和肝静脉管道铸型标本观察其分支与走行,测定各肝叶质量及其所占肝脏百分比。 结果　兔肝肝裂明显,依据肝叶形态、肝裂走行和门静脉主干分支形式将兔肝脏分为五叶,分别为尾状叶、左外叶、左中叶、右中叶、右外叶,各肝叶质量分别为(g)：3.93±1.13、15.93±3.50、14.83±3.31、15.08±4.34、12.08±3.55。左中叶和右中叶根部肝组织融合,其余各肝叶相对独立,尾状叶包括相对独立的乳头突和尾状突两部分。各肝叶有相对独立的Glisson系统和肝静脉走行于肝蒂内。 结论　兔肝解剖学特点与多数哺乳类实验动物肝脏解剖相似,同时又具有其自身特点,适合于肝脏外科疾病动物模型的制作。     

Arterial supply and biliary drainage of the dorsal liver: A dissection study using controlled specimens

Liver surgeons favor using the entity called the 'dorsal liver' (i.e. the caudate lobe and other paracavally located liver parenchyme of segments 7 and 8). According to minute dissection of 48 livers, we describe the territories of the left/right portal veins, hepatic ducts and hepatic arteries in the dorsal liver. In the caudate lobe, the right hepatic artery, rather than the left hepatic artery (23/48 vs 19/48 for right vs left, respectively), tended to supply the 'left' portal vein territory. Similarly, paradoxical drainage patterns, such as the right hepatic duct draining the left portal vein territory, were found in seven of 48 livers. In the territory of the hilar bifurcation, right hepatic artery dominance was also evident and various bile drainage patterns were found. These included double drainage by the bilateral hepatic ducts (3/48) and drainage into the confluence of bilateral ducts (6/48). In contrast, the arterial supply and biliary drainage of the paracavally located parenchyme of segments 7 and 8 usually depended on the proper segmental arteries and ducts and their variations were within the range of those found in other parts of the right lobe. Therefore, the dorsal liver concept may not be anatomical but, rather, simply aimed at usefulness in surgery. Nevertheless, clear subdivision of the caudate lobe according to biliary drainage and/or arterial supply seemed difficult because of the paradoxical relatioships among the portal vein, hepatic artery and bile duct. Consequently, the present results support extended surgery based on the dorsal liver concept for carcinomas involving the caudate lobe.     

左外叶活体肝移植的解剖学研究

目的：模拟左外叶活体肝移植门静脉、肝动脉和胆管的切取方法。方法：解剖正常人肝脏标本30具，观察肝脏铸型标本30具，测量门静脉、肝动脉及胆管长度、管径及属支或分支分布情况。结果：左外叶门静脉的血供来自门静脉左支，主要为左外叶上段门静脉支、左外叶下段门静脉支；动脉主要来源于肝固有动脉、肝左动脉、肝中动脉，偶有迷走动脉支；胆道引流属支有左外叶上段胆管支、左外叶下段胆管支。结论：左外叶解剖变异较多，活体取肝前应仔细研究其结构特点，设计合理的切取模式；对门静脉、肝动脉和胆管支需行必要的整形，以便与受体相应的管道进行吻合。     

Anatomy of the intrahepatic ramification of the portal vein in the right hemiliver

The ramification of the portal vein in the right hemiliver was studied by anatomic dissection in 36 formalin-fixed human livers. In 28/36 (77.8%) cases, the portal vein bifurcated into a right branch and a left branch and the right branch bifurcated into anterior and posterior segmental branches. The anterior segmental branch terminated in the anterosuperior subsegment (S(8)) in two types: bifurcated when it divided into anterior P(8) and posterior P(8 )branches towards the respective regions of S(8) (24/28 cases) and monopodal when it had a single pedicle (4/28 cases). The maximum anteroinferior subsegmental branch (P(5 )maximum) originated either from the anterior segmental branch (16/28 cases) or from the anterior P(8) branch (12/28 cases). The posterior segmental branch vascularized the posteroinferior (S(6)) and the posterosuperior (S(7)) subsegments, and was terminated in three types: fan-shaped (16/28), bifurcated (9/28) and tripodal (3/28). In 4/36 (11.1%) cases the portal vein bifurcated into a right branch and a left branch but the posterior segmental branch was not present. In 4/36 (11.1%) the right branch of the portal vein was not present. These anatomical variations are explained separately and finally all cases are considered as a whole.     

Identification of segments VI and VII of the liver based on the ramification patterns of the intrahepatic portal and hepatic veins

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. Clin. Anat. 12:229–244, 1999. © 1999 Wiley‐Liss, Inc.     

门静脉的解剖与变异

目的：利用经动脉性门静脉造影CT重建门静脉、肝静脉三维结构，观察生理状态下的门静脉的解剖与变异。方法：150例病人，导管置入于肠系膜上动脉内，注入造影剂后门静脉期和肝静脉期连续扫描肝脏。三维重建门静脉及肝静脉，分析门静脉的解剖与变异。结果：150次成像中门静脉变异25例，12例（8．0％）显示门静脉呈三分叉状，10例（6，7％）门静脉先分出右后支，然后上行分为左支和右前支，1例（0．7％）门静脉左支水平段缺如，门静脉右支缺如2例（1．3％），余下125例（83．3％）显示正常左右门静脉分支。结论：门静脉的三维图像重建及类型分析对术前手术方式的确定有一定的临床意义。     

Location of the ventral margin of the paracaval portion of the caudate lobe of the human liver with special reference to the configuration of hepatic portal vein branches

The topographic anatomy of the ventral margin of the paracaval portion of the caudate lobe of the human liver has not been clearly described to date. To this end we hypothesize the existence of a precaudate plane, a flat or slightly curved plane defined by the ventral margins of the ligamentum venosum and the hilar plate. Using 76 cadaveric livers, we investigated whether the paracaval portion of the caudate lobe extended ventral to this plane and whether the paracaval caudate branch of the portal vein (PC) ran through this plane to its ventral side. In 28 of the specimens (36.8%), the PC extended over the plane to a variable depth: less than 10 mm in 10 specimens, 10-20 mm in 10, and more than 20 mm in eight specimens. This ventral extension of the PC consistently included its penetration into the dome-like area under the terminals of the three major hepatic veins; therefore, the ventrally extended PC often interdigitated with these veins and their tributaries (in practice, the ventral margin of the paracaval portion of the caudate lobe could generally be considered to run alongside the middle hepatic vein). Moreover, the ventral extension of the PC often reached the upper, diaphragmatic surface or the dorsal surface of the liver immediately to the right of the inferior vena cava. Several branches (termed border branches) in the ventral extension were difficult to identify as belonging to the PC. We discuss both the marginal configuration of the paracaval portion of the caudate lobe and how to identify and operate on the ventrally extended PC and related border branches during liver surgery.     

胆囊床内血管的应用解剖

目的：为腹腔镜胆囊切除手术提供形态学基础.方法：对128例肝脏标本进行解剖,观察胆囊床内血管的位置、行程,测量其在胆囊床内的长度和直径.结果：胆囊床内血管有：（1）胆囊动脉深支及分支,占71.1%（91例）;（2）肝中静脉及其属支,占12.5%（16例）,其突入形式分①肝中静脉主干,②右前叶支、或左内叶支、或两者一起突出,③右前叶支属支、左内叶支属支、或两者一起突出3种类型;（3）肝门静脉右支及其分支,分主干和分支两类,主干占39.8%（51例）,肝门静脉右支的分支占14.8%（19例）;（4）肝门静脉左支的分支,占2.34%（3例）;（5）胆囊静脉,在胆囊附着面有小静脉与肝中静脉、肝门静脉左、右支的分支相连.结论：切除胆囊时应注意胆囊床左、右缘,以及具有肝门右切迹的病例,保护突入胆囊床内的肝中静脉及其属支,以防止出血.     

Branches of the hepatic artery in red fox

In 30 red foxes (Vulpes vulpes) the origin, course and division of the branches of the hepatic artery were studied. The hepatic artery gave off 3 following branches: right lateral branch, right medial branch and left one. Most often (60% of cases) they arose as a common trunk. In 60% cases the right lateral branch supplied the right lateral hepatic lobe and caudate process of the liver while in 40% cases it supplied the right lateral hepatic lobe, only. Most often (66.7% of cases), the right medial branch supplied the right medial hepatic lobe and gall bladder. In 30% of cases the branch supplied furthermore the quadrate lobe of the liver and in few cases (3.3%) the both, right medial hepatic lobe and quadrate lobe. Rami of the left branch penetrate the left hepatic lobes, papillary process and quadrate lobe (73.3% of cases) and rarely, the left hepatic lobes and papillary process (26.7% of cases).