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1. Surgical anatomy of L iver and Biliary tree Dr Ravi Kumar Meena DNB General Surgery Hindu Rao Hospital

2. Liver-Introduction It’s the largest gland of the body Completely surrounded by a capsule(GLISON’S CAPSULE) Partially surrounded by peritoneum Accounts for about 2% of the body weight of an adult . It has a unique dual blood supply and an intimate relationship with the bile ducts

3. Surfaces of Liver Glison’s capsule extension of the visceral peritoneum. It covers the entire organ EXCEPT The bare area Inferior vena cava (IVC) Gallbladder fossa with the liver hilum ( porta hepatis ). Capsule extends to envelope the hepatic artery, portal vein, and bile duct as these structures enter the liver.

4. Surfaces of liver 1. Antero-superior surface It is smooth and covered by the peritoneum up to the attachment of the triangular ligaments and the anterior layer of the coronary ligament. It is related to the inferior surface of the diaphragmatic dome.

5. Posterior surface The posterior surface, which includes the bare area, is largely retroperitoneal. It is related to the a. Vertical part of the diaphragm, b. The retrohepatic part of the IVC, c. The right adrenal gland and the upper pole of the right kidney. The caudate lobe projects from this surface as an appendage sitting on the surface of the IVC.

6. Inferior or Visceral surface The inferior or visceral surface has an irregular contour as it lies in contact with a number of organs- A. The right anterior aspect of the stomach B. Superior part of the duodenum C. Head of pancreas, gallbladder, common bile duct D. Hepatic flexure of the colon E. Right kidney, and right adrenal gland.

7. PERITONEAL LIGAMENTS OF LIVER: Falciform ligament Coronary ligament (upper & lower layers) Triangular ligament (Right & Left) Lesser omentum and Hepatoduodenal ligament 1 2 3 4

8. 5. Ligamentum teres (Oblit. Lt. paraumb. v.) 6. Ligamentum venosum (Ductus venosus ) 5 5 6

9. A. Falciform ligament It is a crescent-shaped fold which runs between the anterior abdominal wall above the umbilicus and th e anterior surface of the liver. It serves as the surface landmark for the border between The left medial and left lateral sections

10. B. Coronary ligament The anterior and posterior layers of the coronary ligament mark the limit of the bare area as the peritoneum passes from the body wall to the liver surface.

11. c. Triangular ligament The right and left triangular ligaments are formed by the lateral unification of the layers of the coronary ligament on both sides

12. D. Ligamentum teres It contains the obliterated left umbilical vein. Runs in the free edge of the falciform ligament from the umbilicus to the termination of the left portal vein.

13. F. Ligamentum venosum It contains the obliterated ductus venosum that connects the left portal vein to the junction of the left hepatic vein and the IVC in the fetus. It lies on a groove that separates the caudate lobe of liver underneath from the left liver in front. The hepatogastric omentum (lesser omentum ) comprises two layers of peritoneal reflection that connect this groove to the lesser curve of the stomach.

14. E. Hepatoduodenal ligament The hepatoduodenal ligament contains the hepatic artery, portal vein, and bile duct as these structures run from the upper border of the first part of the duodenum to enter the liver hilum .

15. SEGMENTS OF LIVER According to :- Arterial Portal venous blood supply Biliary drainage Hepatic venous drainage forms the anatomical basis for modern hepatic surgery.

16. Couinaud’s anatomic segment of liver

17. The Brisbane 2000 Terminology is based on hepatic artery bile duct eight functional zones or segments of the liver. As seen from an anterior view, the eight segments are numbered in a clockwise direction as described by Couinaud .

18. Starting with the proper hepatic artery, the first division is the right and left hepatic arteries supplying the right and left hemiliver or livers, respectively, and there is very little overlap. The plane between the two distinct zones of blood supply extends from the gallbladder bed anteroinferiorly to the right side of the IVC posterosuperiorly and is called the mid-plane of the liver or Cantlie’s line.

19. The middle hepatic vein lies exactly along this plane. On average, the right li ver to left liver ratio:- Mass 2:1 Volume left liver lobe varies from 20% to 50%

20. The right and left hepatic arteries then divide into four second-order sectional arteries each supplying a section of the liver. On the right side, the two sectional arteries supply the right anterior section and the right posterior section, and the plane between these sections is the right intersectional plane.

21. On the left, the two sectional arteries supply the left medial section and left lateral section. The plane between these sections is the left intersectional plane and is marked by the round ligament at the umbilical fissure and the line of attachment of the falciform ligament to the anterior surface of the liver.

22. The portal vein branching pattern in the right liver follows the same pattern as that of the hepatic artery and bile duct. The right portal vein divides into a right anterior section branch and a right posterior section branch, which further divide into four segmental branches. The left portal vein, however, has a different branching pattern from that of the left hepatic artery and bile duct.

23. C audate lobe ( Segment 1) It is a distinct part of the liver functionally independent of the right and left hemilivers . It is bounded posteriorly by the retrohepatic IVC, and superiorly by the left and middle hepatic veins at their origin. Its anterior border is formed by the left portal vein, the liver hilum , and the base of segment 4.

24. Anatomy of the Caudate Lobe (Segment I). A, Seen in cross section, most of the caudate is to the left of the IVC and lies posterior to the lesser omentum , which separates the caudate from segments II and III. The caudate lobe traverses to the right, insinuating itself between the IVC and the left portal vein (LPV), where it attaches to the right liver. B, Segments II and III have been rotated to the patient’s right, exposing the left side of the caudate

25. The ligamentum venosum also courses along the anterior aspect of the caudate lobe from the left portal vein to the left hepatic vein. The caudate lobe is composed of three parts . The caudate lobe proper , or Spigelian lobe, sits on the left of the IVC and is separated from the left lateral section by the lesser omentum .

26. The paracaval portion of the caudate lobe lies anterior to the IVC. The caudate process (segment 1-r) fuses indistinctly with segments 6 and 7 of the right liver. Since the venous drainage, arterial and portal venous blood supply, and the biliary drainage of the caudate lobe are completely different from those of the right and left livers

27. During Surgery The Brisbane 2000 Terminology of Hepatic Resection is based on the segmental anatomy of the liver. Resection of one side, a section or a segment of the liver is referred to as hepatectomy or hemihepatectomy , sectionectomy or segmentectomy , respectively.

28. ANATOMY OF HEPATIC VEINS The anatomy of the hepatic veins of the liver is closely related to its segmental anatomy as the three major hepatic veins run in the intersectional planes between the four different sections and serve as important landmarks within the liver parenchyma for defining the boundaries between different segments. The venous blood from both the right and the left lobes of liver is collected by the branches of the three main hepatic veins (right, left, and middle), which drain into the suprahepatic part of the IVC below the diaphragm .

29. The middle hepatic vein joins the left hepatic vein to form a common trunk of about 1 cm long in 85% of cases before draining into the suprahepatic IVC. Occasionally, the two veins drain separately into the IVC. The right hepatic vein joins the right side of the IVC at a level slightly below that of the common trunk of the middle and left hepatic veins. There are multiple phrenic veins from both sides of the diaphragm, which drain into the lateral edge of the IVC close to or via the right and left hepatic veins

30. On the posterior aspect of the retrohepatic IVC at the level of the junction with the right hepatic vein, a fibrous band called the IVC ligament ( Makuuchi ligament) courses between the dorsal edge of the left side of the caudate lobe and the right liver. This ligament sometimes contains a bridge of thick liver tissue in which case the retrohepatic IVC will appear to pass through a tunnel in the liver.

31. Hepatic artery In normal anatomy, the common hepatic artery, a branch of the celiac trunk, supplies the right and left livers through its right and left hepatic branches,respectively . The common hepatic artery runs on the left side of the main portal vein in the hepatoduodenal ligament and may divide into right and left branches anywhere between its origin and the hilum of the liver. The division usually takes place to the left of the hilum , resulting in a longer right hepatic artery.

32. The right hepatic artery courses laterally to the right, posterior to the common hepatic duct and right hepatic duct but anterior to the portal vein. It gives off the cystic artery and eventually divides into the anterior and posterior sectional arteries before entering the liver parenchyma. The cystic artery crosses the common hepatic duct posteriorly or anteriorly . As it runs toward the gallbladder, it courses through the hepatocystic triangle ( Calot’s triangle)

33. Anatomical variants of the extrahepatic artery are common only 55% of population has a normal anatomy. A variant can be a replaced artery that serves as the only arterial blood supply for a particular part of the liver while the artery in normal location does not exist, or an accessory one that provides dual supply for a volume in conjunction with the normal artery. It may supply a segment, section, hemiliver , or even the whole liver.

34. The commonest arterial variant is Left hepatic artery arises from the left gastric artery It is found in 25% of cases. Right hepatic artery originates from the s uperior mesenteric artery It is present in about 17% of cases. More rarely, the common hepatic artery arises wholly from the superior mesenteric artery in 2.5% of cases, and occasionally it arises from the left gastric artery or the aorta.

35. In about 75% of population, there is a normal anatomical relationship between the right hepatic artery and the common hepatic duct, that is, the hepatic artery courses posterior to the bile duct. However, the right hepatic artery may run an aberrant course anterior to the bile duct or even posterior to the portal vein. The cystic artery may arise from the right hepatic artery on the left side of the common hepatic duct and may run anterior to it. It may also arise from an aberrant right hepatic artery.

36. The middle hepatic artery is defined as an extrahepatic arterial branch that originates from the liver hilum and enters the umbilical fissure to supply segment 4 and occasionally part of segment 2 or 3 . It exists in about 70% of population, and in the remaining 30%, this hilar vessel does not exist and the arterial supply for segment 4 comes from the left hepatic artery within the umbilical fissure. The middle hepatic artery originates from the right hepatic artery (44%) or, less commonly, the left hepatic artery (26%) when the hepatic arterial anatomy is normal

37. During Surgery During cholecystectomy , the cystic artery is usually identified as it runs in the Calot’s triangle toward the gallbladder. Elevation of the undersurface of the liver together with lateral retraction of the neck of the gallbladder allows better exposure for clearance of this triangle and safe identification of cystic structures.

38. Depending on the site of branching of the cystic artery and the point of dissection, a single cystic artery or its anterior and posterior branches may be encountered and divided separately. Occasionally, the right hepatic artery runs an unusually tortuous course low in the Calot’s triangle and the cystic artery is very short. Inadvertent injury of the right hepatic artery may occur unless the dissection is kept close to the surface of the gallbladder.

39. Portal Vein The main portal vein divides at the liver hilum into the right and left portal veins, supplying the right and left livers, respectively. The right portal vein lies anterior to the caudate process and enters the right liver through the hilar plate, dividing into anterior and posterior branches. The right anterior portal vein runs forward in a vertical plane, and it divides into descending and ascending branches for segments 5 and 8, respectively.

40. The anatomy of the left portal vein is constant. The right portal vein has more anatomical variations. Normal right portal vein anatomy where a right portal vein bifurcates into a right anterior vein and a right posterior vein occurs in 75% of cases. In 10% of cases, a trifurcation of the main portal vein occurs, where the right portal vein immediately divides into two sectional branches.

41. In about 12% of cases, a right portal vein does not exist and a right posterior sectional branch coming from the left portal vein at a short distance after the main portal vein gives off a right anterior portal vein branch . Anatomical variants of the portal vein are closely associated with those of the biliary tract in 80% of cases.

42. In the operating room In the event of a portal vein trifurcation or the right posterior portal vein branch arising from the left portal vein, an unsuspecting surgeon conducting right hepatectomy may mistake the lower sectional branch for the right portal vein, only to find the second sectional vein during parenchymal transection .

43. Left Hepatectomy For left hepatectomy , the shortness of the transverse portion of the left portal vein under such circumstances may create difficulty in its safe isolation and division. Isolation and division of branches to the caudate lobe (segment 1) is the key to allow adequate length for the procedure. When the extrahepatic left portal vein is absent, a catastrophic complication may happen during right hepatectomy as the main portal vein may be mistaken for the right portal vein as it enters the liver in a position similar to the right portal vein.

44. EXTRAHEPATIC BILIARY SYSTEM Consists of : Rt. hepatic duct Lt. hepatic duct Com. hepatic duct Cystic duct Com. Bile duct Gallbladder 3 4 5 6

45. 3 4 5 6 HEPATIC DUCTS : Emerge from porta hepatis Rt. & Lt. HDs unite to form CHD CHD =4 cm CHD descend in lesser omentum Joined by cystic duct to form CBD

46. 3 4 5 6 COMMON BILIARY DUCT: 8cm long 1 st course (Lesser Omentum) 2 nd course (behind 2 nd Duo.) 3 rd course ( post. To head of pancreas )

47. 4 3 5 6 Hepatopancreatic ampulla of vater Major duodenal papilla Sphincter of Oddi

48. GALLBLADDER ( Basic Introduction) : Under the liver Stores 30-50 ml of bil e Divided into : Fu n d u s Body Neck 1 2 3

49. RELATIONS OF GALLBLADDER: ANTERIORLY: Ant. Abdominal wall Inferior surface of liver POSTERIORLY : Transverse colon 1 st & 2 nd duodenum

50. BLOOD SUPPLY: ARTERIAL : Cystic artery VENOUS : Cystic vein LYMPHATICS : A cystic LN at the neck of GB NERVES : Autonomic from coeliac plexus Cholecystokinin

51. The gallbladder sits on the cystic plate on the inferior surface of the liver at its mid-plane. Its relation to the liver ranges from hanging from a loose peritoneal reflection to being deeply embedded within the liver parenchyma.

52. The normal biliary anatomy exits in only about 50% of population. The right hepatic duct, which has a short extrahepatic course of only about 1 cm, is formed by the confluence of the right anterior and right posterior sectional ducts at a variable point in its intrahepatic course. The right anterior sectional duct drains segments 5 and 8. It lies vertically and is located to the left of the right anterior portal vein. The right posterior sectional duct drains segments 6 and 7.

53. It courses horizontally and usually runs superior to the right anterior portal vein ( epiportal ) to join the right anterior duct, forming the right hepatic duct above the right portal vein . In about 20% of cases, the right hepatic duct runs inferior ( hypoportal ) to the right anterior portal vein. In rare situations, there is a combined pattern in which some branches of the right posterior sectional duct enter the distal bile duct supraportally and the remaining branches infraportally .

54. In the left liver, segment-2 and -3 segmental ducts fuse to form the left lateral section duct, which then unites with one or more branches from segment 4 to form the left duct. The left duct runs horizontally from left to right for a distance of 2 to 3 cm along the base of segment 4, first above and then behind the left portal vein, until it joins the right duct to form the common hepatic duct.

55. The right hepatic duct is frequently absent and a common biliary anatomical variant in the right liver involves a sectional or segmental bile duct joining the left hepatic duct to form a triple confluence . On the other hand, a sectional or segmental duct may join the common hepatic duct well below the normal confluence.

56. Variations of the Hepatic Duct Confluence. A, Most common anatomy. B, Trifurcation at the confluence. C, Either of the right sectoral ducts drains into the common hepatic duct. D, Either of the right sectoral ducts drains into the left hepatic duct. E, Absence of a hepatic duct confluence. F, Absence of right hepatic duct and drainage of right posterior sectoral duct into the cystic duct

57. Large gallstones impacting within the neck of the gallbladder may create a Hartmann’s pouch before it narrows toward the cystic duct, which is normally about 1 to 2 cm long and contains the spiral valves .

58. Variability in cystic duct anatomy

59. The cystic duct joins the common hepatic duct to form the common bile duct at a variable site ranging from the right hepatic duct to the ampullary region. The configuration of the cystic duct with the common hepatic duct follows three patterns. In the majority, the cystic duct joins the common hepatic duct at an acute angle (75%).

60. In others, the cystic duct runs parallel to the right side of the common hepatic duct for a distance (20%) or spirals posterior to the common hepatic duct before entering on its left side (5%). The common bile duct runs downward at the right lateral edge of the hepatoduodenal ligament, with the common hepatic artery on its left and the main portal vein at its back.

61. It passes posterior to the first part of the duodenum and crosses behind the pyloric vessels and the pancreaticoduodenal arteries. Then it continues behind or in the posterior part of the head of pancreas, forming its retropancreatic portion before passing through the Sphincter of Oddi to enter the second part of the duodenum at the major papilla .

62. The major papilla protrudes into the duodena l lumen at 8 cm from the pylorus. The pancreatic duct forms a common channel with the common bile duct in 85% of cases, but occasionally the two ducts enter the duodenum separately.

63. In the Operating Room During cholecystectomy , several anatomical variants may predispose to biliary complications. The parallel configuration of the confluence of the cystic duct and the common hepatic duct may predispose the common hepatic duct to injury at the side, particularly if dissection is performed with diathermy. Tiny bile ducts (ducts of Luschka ) may enter the gallbladder through the cystic plate and may be divided.

64. A right hepatic sectional duct, which joins the common hepatic duct at a low level may be mistaken for the cystic duct and be injured. The risk is even higher if the cystic duct actually drains into this aberrant duct . To avoid this complication, it is important to avoid excessive use of powerful hemostatic devices to dissect the gallbladder and the bile duct. Before a tubular structure thought to be the cystic duct is divided, its anatomy should be carefully delineated by dissection toward the infundibulum so as to ensure that the structure does end in the gallbladder

65. Biliary complication is a common and serious morbidity after liver surgery and liver transplantation. Knowledge of the biliary anatomy can be obtained by preoperative magnetic resonance cholangiography , but an intraoperative cholangiogram preferably with radiopaque markers provides more detailed information and better localization.

66. Since the right liver is anatomically right posterior and the left liver left anterior, the mid-plane is slanting from right anterior to left posterior and the best direction for a cholangiogram is a right anterior oblique view . Intraoperative cholangiography should therefore be performed under fluoroscopy.

67. When the anteroposterior view is rotated to a right anterior oblique view, the branches of the right anterior section duct will move medially while those of the right posterior section duct will move laterally, and the true length of the right and left hepatic ducts will be more clearly delineated

68. Most lymph node drainage from the liver is to the hepatoduodenal ligament. From here, lymphatic drainage usually continues along the hepatic artery to the celiac lymph nodes and then to the cisterna chyli . Lymphatic drainage can also follow the hepatic veins to lymph nodes in the area of the suprahepatic IVC and through the diaphragmatic hiatus. The lymphatic drainage of the gallbladder and most of the extrahepatic biliary tract is generally into the lymph nodes of the hepatoduodenal ligament. This drainage may follow along the hepatic artery to the celiac lymph nodes, but it can also flow into lymph nodes behind the head of the pancreas or within the aortocaval groove. Lymphatics

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