Surgical anatomy of the vasculobiliary apparatus at the hepatic hilum as applied to liver transplantations and major liver resections

Introduction

To evaluate the hepatic arterial, bile duct and portal venous anatomy as applicable to major liver resections.

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。     

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.     

基于肝内肝门静脉解剖的肝脏右前叶分段新概念

目的根据肝内肝门静脉的走形分布,提出肝脏分段的新概念,为影像学和肝脏外科提供资料。方法采用60例正常的活体肝移植供肝影像资料,研究右前叶肝内肝门静脉的走形和分布以及肝静脉及其属支的回流范围,10例Mevis三维软件重建图像,探讨两者之间的关系。结果 Couinaud分段中的Ⅷ段门脉支可大致分为腹侧支和背侧支,最多可达4支;约90%的背侧支越过肝右静脉分布到Couinaud分段中的VII段。V段的门脉分支大多来自右前叶或Ⅷ段门脉的腹侧支。因此,可将右前叶分为腹侧段:Couinaud分段中的Ⅷ段的腹侧段(S8v)和V段(S5)背侧段:Couinaud分段中的Ⅷ段的背侧段(S8d)两个部分。结论新的划分方法不仅有利于肝内病变的精确定位,而且便于肝脏外科实施新的、更安全的术式。     

Vascular branching pattern and zonation of gene expression in the mammalian liver. A comparative study in rat,mouse, cynomolgus monkey,and pig

Background: A significant part of the liver volume consists of regions in which hepatocytes are in close contact with large branches of the afferent (portal vein) or efferent (hepatic vein) vessels. As most studies have addressed zonation of gene expression around the parenchymal branches of the portal and hepatic vein only, the patterns of gene expression in hepatocytes surrounding larger vessels are largely unknown. Methods: For that reason, we studied the patterns of expression of the mRNAs and proteins of the pericentral marker enzymes glutamine synthase, ornithine aminotransferase, and glutamate dehydrogenase and the periportal marker enzymes phosphoenolpyruvate carboxykinase and carbamoylphosphate synthase in the rat liver, in relation to the branching pattern of the afferent and efferent hepatic veins with immuno and hybridocytochemical techniques. These patterns of expression were compared with those seen in mouse, monkey, and pig liver. Results: The distribution patterns of the genes studied appear to reflect the “intensity” of the pericentral and periportal environment, glutamine synthase and phosphoenolpyruvate carboxykinase requiring the most pronounced environment, respectively. The patterns of gene expression around the large branches of the portal and hepatic vein were found to be related to the parenchymal branches in the neighbourhood of these large blood vessels. Only the cells of the limiting plate retain their periportal and pericentral phenotype for those marker enzymes that do not require a pronounced periportal or pericentral environment to be expressed. GS-negative areas in the pericentral limiting plate appear to correlate with a local absence of draining central veins, and become more frequent and extensive around the larger branches of the hepatic vein. Conclusions: The similarity of the observed patterns of gene expression of the genes studied in mouse, rat, monkey, pig, and man suggests that they reflect a general feature of gene expression in the mammalian liver. A comparison of mouse, rat, pig, and human liver suggests that the presence of glutamine synthase-negative areas reflects the branching order of the efferent hepatic blood vessel. © 1994 Wiley-Liss, Inc.     

肝门静脉解剖和影像三维重建的临床应用

目的 观测门静脉肝内段二级分支的形态特征和分支分布规律,为诊断和治疗肝脏疾病提供更为详尽的解剖学及影像学资料。 方法 100例无肝病的成人多排螺旋CT（64-MSCT）增强扫描肝门静脉获得数据,利用CT自带的GE ADW 4.5工作站对其进行三维重建,并结合50例成人肉眼无病变尸肝对肝门静脉进行解剖剥离,观测及比较肝门静脉分支规律并采集相关数据进行统计学分析。结果 影像重建和大体解剖的近第1肝门处肝门静脉内径分别为（11.20±1.48）mm和（10.86±2.01）mm;左、右支主干夹角分别为（93.58±24.03）°和（105.59±13.82）°;左支横部长分别为（29.50±6.51）mm和（23.90±5.29）mm,中点内径分别为（7.70±1.55）mm和（7.43±1.09）mm;右支主干长分别为（21.77±10.35）mm和（20.63±6.59）mm;中点内径分别为（9.10±1.66）mm和（9.26±1.77）mm。依据肝门静脉的分支情况可将其分为4型。结论 肝门静脉变异情况并不少见,其分支的直径与夹角等均存在一定的变化,在肝外科手术实施时,对门静脉主干分支各型应给予高度的重视。     

A study of the accessory hepatic vein to segments VI and VII with a morphological reconsideration of the human liver

Introduction The liver is supplied by the common hepatic artery from the celiac trunk and by the portal vein from the gastrointestine. This double blood supply to the liver by the hepatic artery and the portal vein produced a complicated structure in the liver. For the blood outflow, we can see right, intermediate and left hepatic veins, and irregular veins: the accessory hepatic veins. These veins drain the blood in the liver into the inferior vena cava. In this study, we studied the layout of the accessory hepatic vein draining segments 6 and 7 in the human livers and attempted to reconsider the structure of the liver by the layout of the accessory hepatic vein. Methods Sixty livers were subjected in this study. They were prepared by using forceps to trace the layout of the blood vessels inside the livers. We carefully examined the relation between the layouts of the accessory vein to the segments 6 and 7 and of the portal vein. The confluence patterns of the accessory hepatic vein into the inferior vena cava were also examined to find the character of the vein. The relation between the accessory hepatic vein and standard hepatic veins was also studied. Results We found 2.2 accessory hepatic veins in one liver on average in our study. The vein was always within the area of segments 6 and 7, and did not surpass the boundary. We found at most five accessory hepatic veins in a liver in two cases. The accessory hepatic vein to the segments 6 and 7 always had its stem on the dorsal side to the portal vein. Different from the stem, the periphery of the accessory hepatic vein freely distributed with the peripheral branches of the portal vein. The area distributed by the accessory vein was also always dorsal part within the segments 6 and 7. The vein was small usually, but was big in few cases. When the vein was big, the area became solely drained by the accessory vein, because the standard hepatic veins (right and intermediate hepatic veins) did not reach the area, and we did not find any communication between the accessory vein and the standard veins. As the remaining region in the segments 6 and 7 became smaller, the draining right standard hepatic vein became shorter and smaller. Discussion The region drained by the accessory hepatic vein excluded the standard hepatic veins. Therefore, there are two different draining venous networks in the area of segments 6 and 7 classified by Couinaud. Conclusion The accessory hepatic vein draining segments 6 and 7 distributed somewhere dorsal side in the segments 6 and 7. The area where the accessory vein distributed was the region where standard hepatic veins did not reach. This would suggest that the region drained by the accessory hepatic vein makes an isolated segment in the liver in the segments 6 and 7 by the Couinaud’s Classification. The area might have a unique blood circulation system.     

肝门静脉的应用解剖

目的观测肝门静脉的形态特征和分支分布规律,为诊断和治疗肝脏疾病提供更为详尽的形态学资料。方法 50例肉眼观察无病变的成人肝标本,对肝门静脉分支分型等形态特征进行解剖观察,测量肝门静脉主干及其主要分支的相关数据并进行统计学分析。结果肝门静脉主干54.0%在肝实质外分叉,其分叉点距肝实质的垂直距离为(8.94±3.17)mm;34.0%紧贴肝实质分叉。左支主干长(47.44±7.23)mm;左支横部长(23.90±5.29)mm,外径为(7.43±1.09)mm,矢部长(24.02±4.97)mm,外径为(7.07±1.36)mm,角部角度为(114.18±22.59)°;右支主干长(20.63±6.59)mm,外径为(9.26±1.77)mm。依据肝门静脉的分支情况可将其分为8型。结论肝门静脉变异情况并不少见,其分叉点距肝实质的垂直距离及左、右支主干径值与分支等均存在一定的变化,在肝外科手术实施时,对肝门静脉主干分支各型应给予高度的重视。。     

Portal Venous Territories Within the Human Liver: An Anatomical Reappraisal

Subdivision of the human liver into eight portal venous segments (according to Couinaud) is largely established in the anatomical and clinical community. However, this concept is challenged by an increasing number of surgical and radiological reports. We reexamined the intrahepatic portal venous architecture to understand the inconsistencies published. For this purpose, we studied the livers of 20 deceased who had donated their body to the Anatomy Department. The organs were investigated by portal venous injection, subsequent liver corrosion, and analysis of the branching pattern. After a usual bifurcation of the portal vein (order 0 vessel) into a right and left branch (first order vessels), the number of second order branches observed was between 9 and 44, with an average of 20. This seemingly trivial matter of fact suggests that the human liver does not consist of the eight segments presumed, but of many more. Supposedly contradictory observations turn out to be explainable by differing combinations of this large number of territories, and not simply by anatomical variability. For practical surgical purposes, we conclude that the useful eight‐segment scheme needs conceptual reappraisal when a more realistic approach to the individual hepatic territoriality in the patients under consideration is demanded. We submit a “1‐2‐20‐concept” as a possible key. Anat Rec, 291:636–642, 2008. © 2008 Wiley‐Liss, Inc.     

三维动态对比增强磁共振肝门静脉造影成像效果及解剖学分析

目的：探讨三维动态对比增强磁共振肝门静脉造影(3DDCEMRP)的成像质量并观测肝内肝门静脉的解剖和变异。方法：共进行61例门静脉3DDCEMRP检查，通过对MPV、LPV、RPV，SV及SMV显示情况和对门脉右支显示能力的分析，评价3DDCEMRP的成像质量。测量门脉系统各主要干支的径线并对门静脉的解剖和变异做分型，计算各型的构成比。结果：所有病例均完整显示门静脉主干及肝内4级以上分支。61次成像中，4例(6．6％)显示门脉主干呈三叉状，3例(4．9％)门脉主干先发出右后支，继续上行分为左支和右前支，2例(3．3％)门脉右前支起自左支，l例(1．6％)门脉右支缺如，其余5l例(83．6％)显示正常门脉分支。结论：肝内门脉变异并不少见，3D DCE MRP是一种有效、微创技术。能方便而清楚地显示肝内门脉的解剖和蛮异。     

肝蒂内结构肝内分支的形态观测及临床意义

目的研究肝蒂内结构在肝内的分布状况,对肝叶及肝段进行量化分析;探讨肝脏手术时血管和胆管的保护及定位标志,为相关临床科室手术提供解剖学依据。方法取20例无肝病死亡后的人体肝脏标本及肝脏铸形标本,用游标卡尺和三角尺等进行有关数据的测量,所的数据用SPSS10.0软件进行统计学分析。结果肝蒂内结构入肝实质后三者以肝门静脉分支为主轴,攀附伴行。门静脉大多分为左、右干,部分右干缺如,且右干变异较大,肝管汇合方式常见为3型。结论肝脏血管丰富,解剖结构复杂,出血难以控制。肝脏的分叶与分段对于肝脏手术具体方式有指导作用。每一肝段都有它的单独管道系统,可以作为一个外科切除单位。     

Recovery from hepatic necrosis following acute portal vein embolism with special reference to reconstruction of occluded vessels.

We examined the morphological and haemodynamic changes in the livers of rats following acute obstruction of portal vein branches by the injection of agar into the portal vein. Histological and angiographic examinations of the liver were performed after measurements of portal vein pressure in vivo and portal vascular resistance by an isolated liver perfusion method. Portal vein embolism induced hepatic necrosis in the centrilobular and midzonal areas, which was rapidly resorbed and replaced by regenerated liver cells leaving no trace. This recovery from hepatic necrosis was closely related to recanalization of obstructed portal vein branches, which led to falls in both the elevated portal vein pressure and the increased portal vascular resistance following embolization.     

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.     

Reconfirmation of the right medial division of the portal venous system of liver

With the development of hepatic surgery and radiology, an increasing amount of researchers have reported discrepancies between the real distribution of the hepatic portal vein branches and Couinaud's segmentation, especially for further division of the right medial division. The present study investigated 25 cadaveric liver dissections and 30 three-dimensional reconstruction images of intrahepatic vessels. The ramifications, course, distribution and quantity of the portal branches were analyzed. An oblique fissure that had few vessels was found among third-order branches of the hepatic portal vein of the right medial division. The right medial division could be redivided into the ventral subsegment and dorsal subsegment by this oblique fissure. A hepatic vein coursed in the oblique fissure between the ventral subsegment and dorsal subsegment. The hepatic vein could serve as an anatomical landmark of the inter-subsegmental plane. This new method of identifying further division of the right medial division is a novel concept providing further information on conventional segmental anatomy.     

肝静脉与门静脉的解剖及其在经颈静脉肝内门体分流术中的应用

目的：探讨肝静脉与门静脉的解剖及在经颈静脉肝内门体分流术（TIPS）中的应用。方法：在PUBMED、CNKI及维普等数据库中,查阅近年来国内外有关肝静脉、门静脉的正常解剖与变异及其在TIPS中应用的文献,进行分析总结。结果：肝静脉系统主要由肝右静脉、肝中静脉、肝左静脉3支组成,肝左静脉发生变异最多,肝中、右静脉变异相对少见。门静脉在肝门处进入肝脏,以分为左支和右支两主干这一类型居多,其解剖形态因地区、种族等因素而有差异。肝静脉和门静脉呈向后向上与向前向下的空间关系,经典TIPS是从肝右静脉距下腔静脉入口约2cm处向门静脉分叉部或右支内穿刺建立分流道。结论：肝静脉、门静脉的正常解剖与变异及其空间关系对顺利完成TIPS的操作至关重要。熟悉肝静脉、门静脉正常解剖和变异可提高TIPS的成功率,减少和避免并发症的发生。     

肝门静脉左支分支分型的数字化研究及编码分析

目的　探究肝门静脉左支新的分型和研究方法，为肝数字解剖研究提供数据和参考。 方法　应用Hisense CAS对110例国人上腹部增强CT数据进行肝血管三维重建，准确显示肝门静脉左支的三维图像。分析肝门静脉左支分支的形态特点及分布规律，进行编码并统计分析。 结果　根据门静脉左支走行特点可分为6型：I型61例（55.45%），II型29例（26.36%），Ⅲ型13例（11.82%），IV型4例（3.64%），V型2例（1.82%），VI型1例（0.91%）。 结论　Hisense CAS能够准确地显示肝门静脉三维影像，方便进行肝内管道观察，为肝门静脉分支分型的数字解剖学研究提供了很好的工具；针对较大数据的观测，用编码的方法非常方便统计分析。     

Right ligamentum teres joining to the right branch of the portal vein

Ligamentum teres joining to the right branch of the portal vein in a 79-year-old Japanese male cadaver was noted during student dissection at Kumamoto University in 2004. The ligamentum teres entered the liver along the left side of the gallbladder fossa. The quadrate lobe was not distinguished from the left lobe in the visceral surface. When the liver parenchyma was removed by tearing off to expose the branches of the portal and hepatic veins, it was clarified that the ligamentum teres unusually joined to the bifurcation of the upper anterior and lower anterior branches of the right branch of the portal vein. The ligamentum teres is the remnant of the umbilical vein working throughout fetal life. Initially a pair of the umbilical veins entered the sinus venosus. During the fourth and fifth weeks they connect to the hepatic sinusoids, which become the portal and hepatic veins, and the parts entering the sinus venosus of both umbilical veins disappear. By the eighth week, as all remainder of the right umbilical vein disappears, the left umbilical vein is the only one to carry blood from the placenta to the liver. It results in the ligamentum teres joining to the left branch of the portal vein. However, in the present case it is thought that the right umbilical vein remained instead of the left one for some reason, and it then became the right ligamentum teres joining to the right branch of the portal vein.     

Variations and topography of the arteries in the lesser omentum in humans

Modern surgical techniques depend in part on knowledge of both the “normal” and the anomalous arterial blood supply. For instance, in liver transplantation, during surgery of the gall-bladder, gastrectomy, and gastric lymphadenectomy, or when selective arterial chemotherapy is used for treatment of liver cancer, aberrant hepatic arteries can be a significant problem. A series of 138 cadavers with arterial latex injection were dissected and 10 corrosion casts were made to obtain an exact knowledge of the topography of the normal and anomalous arteries of the lesser omentum in humans. The so-called normal anatomy was found in only 9% (15 of 148 individuals), the remaining five-sixths presenting some variations from this, many of direct surgical importance. In these cases one or two aberrant hepatic arteries (37%), an artery in the free border of the hepatoduodenal ligament (19%), a right hepatic artery crossing the portal vein posteriorly (4%), the right hepatic artery entering the triangle of Calot anteriorly (29%) or not (7%), or an accessory left gastric artery branching off the left hepatic artery (2%) were found. © 1996 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。     

Absence of the portal bifurcation at the hilum of the liver due to intrahepatic origin of the left branch of the portal vein

Abstract The authors report a rare anomaly of portal vascularization which was detected by CT-scan and MRI and then confirmed surgically. There was no portal bifurcation at the hilum of the liver. After giving off its right dorsal branch, the portal vein entered the right liver and divided in the parenchyma into the right ventral and left branches. The arterio-biliary distribution was normal. Only a few similar cases have been reported. The left branch of the portal vein is reported to have few variations in contrast with the right one, which has many. The venous structure of the liver varies increasingly with the distance from the left umbilical vein. During a right hepatectomy, the possibility of such a vascularization makes it necessary to ensure that the left branch of the portal vein starts upstream before dividing a portal branch entering the right liver.