Liver biopsy, resections and a brief overview of transplantation

Core procedures

Right hepatectomy for malignancy
Left hepatectomy for malignancy
Extended right hepatectomy for malignancy
Extended left hepatectomy for malignancy
Live donor right hepatectomy
Live donor left hepatectomy
Caudate lobe resection

Clinical anatomy

Liver resection (LR) is divided into anatomical and non-anatomical resections. Non-anatomical LR refers to the partial resection of parenchyma in one or more liver segments, while anatomical LR refers to the complete resection of one or more liver segments ( Table 62.1 ).

TABLE 62.1

Commonly performed liver resections, corresponding segments and divided structures

Liver resection/divided structure	Segments	Hepatic artery	Portal vein	Hepatic vein	Bile duct
Right hemihepatectomy	5, 6, 7 and 8	Right hepatic artery	Right portal vein	Right hepatic vein	Right hepatic duct
Left hemihepatectomy	2, 3 and 4	Left and middle (A4) hepatic arteries	Left portal vein	Left hepatic vein	Left hepatic duct
Left lateral sectionectomy	2 and 3	Left hepatic artery	Left portal vein branches to segments 2 and 3 (P2 and P3)	Left hepatic vein	Bile duct tributaries from segments 2 and 3 (B2 and B3)
Right posterior sectionectomy	6 and 7	Right posterior hepatic artery	Right posterior portal vein	Right hepatic vein	Right posterior hepatic duct
Extended right hemihepatectomy	4, 5, 6, 7 and 8	Right and middle (A4) hepatic arteries	Right portal vein and left portal vein branches to segment 4 (P4)	Right and middle hepatic veins	Right hepatic duct and bile duct tributaries from segment 4 (B4)
Extended left hemihepatectomy	2, 3, 4, 5 and 8	Left, middle (A4) and right anterior hepatic arteries	Left and right anterior portal veins	Left and middle hepatic veins	Left and right anterior hepatic ducts
Caudate lobe resection	1 and 9	Caudate branch from left, proper or right hepatic artery	Caudate branches from left and right portal veins	Short hepatic veins to the inferior vena cava and caudate tributaries to the middle hepatic vein	Bile duct tributaries from caudate lobe (B1 and B9)

The first step in LR is mobilization of the liver by division of its peritoneal attachments. Division of the falciform ligament towards the diaphragm leads to the suprahepatic inferior vena cava (IVC) and the three hepatic veins. The left hemiliver is mobilized by dividing the left triangular peritoneal attachment. The pars flaccida of the gastrohepatic ligament is divided and the pars densa, which contains the hepatic branch of the vagus nerve, is examined for aberrant left arteries or veins. Division of these structures allows the exposure of sulcus of Arantius and the ligamentum venosum; division of the ligamentum venosum allows for extraparenchymal control of the left hepatic vein (LHV) and/or middle hepatic vein (MHV) ( Fig. 62.1 ). The space between the round ligament and the liver parenchyma between segments 3 and 4 is known as the space (recess) of Rex. Division of the parenchyma covering the space of Rex caudally can expose the pars umbilicalis of the left portal vein (LPV) and its branches ( Fig. 62.2 ).

Fig. 62.1, The sulcus of Arantius, as observed after mobilizing the left hemiliver and dividing the ligamentum venosum. Note the groove between the inferior vena cava (IVC) and the left hepatic vein (LHV). This space can be further dissected to obtain extraparenchymal control of the LHV during left lateral liver section or left hemihepatectomy. Other abbreviations: LPV, left portal vein; MHV, middle hepatic vein; PV, portal vein; RPV, right portal vein.

Fig. 62.2, A , The approach to ‘anatomical’ extended right hemihepatectomy. On entering the space of Rex, the right-sided (segment 4) branches of the pars umbilicalis of the left portal vein are dissected independently, ligated and divided.

The right hemiliver is mobilized by dividing the right triangular ligament and the right part of the coronal peritoneal attachments. Division of the retrocaval (Makuuchi's) ligament allows identification of the right hepatic vein (RHV) and the groove between the RHV and MHV. The caudate lobe is mobilized by dividing the retrocaval ligament and the parietal peritoneum covering the adventitia of the IVC, after mobilizing both the left and right hemilivers. Full mobilization of the caudate lobe requires ligation and division of its caval outflow. The hepatic pedicles, which contain the branches of the hepatic artery, portal vein and bile ducts, can be accessed by first separating the confluence of the hepatic ducts from the base of segment 4b, a manœuvre known as lowering the hilar plate ( Fig. 62.3A ). This space, directly above the hepatic duct confluence, can be traced to the other side of the incisura transversa (sulcus of Haller) and used to encircle the left and right pedicles. The pedicles can be divided en bloc without dissecting out the individual structures (extra-Glissonian approach). The division of the cystic extension of the hilar plate allows identification of the right anterior pedicle, which can be approached in a similar fashion. The right posterior pedicle can be identified in Rouvière's sulcus.

Fig. 62.3, The hilar/plate system. A , Division of the peritoneum covering the hepatoduodenal ligament allows creation of the avascular virtual space between the liver capsule and the hilar plate (arrow denotes the right hepatic duct, right hepatic artery and the portal vein). B , The hilar plate continues around the pedicles of each segment, which contain its inflow and bile ducts. The plate can be divided in cystic, hilar, Arantial and umbilical plates.

The rationale for these manœuvres is the concept that the liver capsule surrounds the liver parenchyma independent of the parietal peritoneum and the adventitia of the IVC, even in the bare area of the liver, and the portal pedicles and the hepatic veins. The plate/sheath system is independent from the liver capsule. It is a thick layer of fibrous connective tissue that has been described as a shirt with the front cut away, leaving the back and the sleeves ( Fig. 62.3B ). It can be divided in the plate (back of the shirt) and the Glissonian sheath around the sectorial and segmental portal pedicles (sleeves). It can be further divided into four: the cystic plate in the gallbladder fossa, the hilar plate around the incisura transversa, the Arantian plate around the ligamentum venosum, and the umbilical plate around the pars umbilicalis of the LPV.

Liver resection

Liver resections include oncological resections for liver tumours, live donor hepatectomy, and resection of tumours that involve the hilum of the liver (such as hilar cholangiocarcinoma) ( Table 62.2 ).

TABLE 62.2

Different types of liver resection

Type of liver resection (LR)	Goal	Anatomical criteria	Liver volume criteria *
LR for liver tumours	Resect the involved part of the liver with negative margins	After resection, the patient should be left with at least two adjacent segments with an intact vascular inflow, outflow and biliary drainage	≥20–40% depending on the degree of underlying liver disease
LR for hilar tumours and cholangiocarcinoma	Resect the involved part of the bile duct and the liver with negative margins	After resection, there should be a margin of at least 10–20 mm between the bile duct tumour and the bile duct division point. The patient should be left with at least two adjacent segments with an intact vascular inflow, outflow and biliary drainage	≥25% after biliary decompression
LR for living donation	Resect the intended part of the liver while leaving enough functioning liver for the donor and providing a large enough graft for the intended recipient	After resection, the donor should be left with at least four adjacent segments with an intact vascular inflow, outflow and biliary drainage	≥30%

* Percentage of functional liver volume required to remain in the patient.

Oncological resection for liver tumours

The goal is to resect the involved part of the liver with negative margins (R0 resection) while preserving enough functioning liver parenchyma with an intact vascular inflow and outflow and biliary drainage. Adequate liver parenchyma is defined as a minimum of two adjacent liver segments with intact vascular inflow and outflow, biliary drainage and a future liver remnant volume of 20–40%, depending on the condition of the liver parenchyma. The affected parenchyma is resected; the dissection of hilar structures depends on the surgeon's preference and the extent to which it has been invaded by the tumour. The hilar structures can be dissected and ligated independently (intra-Glissonian) or they can be addressed without dissecting them out (extra-Glissonian approach).

Liver resection for live donor hepatectomy

The safety of the donor is the most important part of a living donor hepatectomy operation. The goal of this procedure is to ensure that enough functioning liver parenchyma is left in the donor while providing the intended recipient with unharmed vasculature and bile duct in the graft. The minimum amount of future liver remnant required in the donor is 30–35% to ensure safe donation. Every effort is made to preserve a proper haemostatic parenchymal transection plane, free of bile leaks, taking care to preserve the vascular and biliary structures that remain in the donor. The main technical differences between live donor hepatectomy and oncological hepatic resection are: firstly, parenchymal transection is performed without dividing the inflow and outflow, while accurately identifying and preserving intrahepatic tributaries of the hepatic vein (for example, segment 5/8 veins); secondly, the dissection of the bile duct is performed close to the bile duct confluence in order to preserve the blood supply of the bile duct of the intended graft and also preserve the integrity of the donor's common hepatic duct; and thirdly, division of the vascular structures is performed at the end of the operation just prior to excision of the graft.

Hilar tumours

Liver resection for tumours that involve the hepatic hilum (e.g. hilar cholangiocarcinoma) is more complex. Extensive dissection of the vascular structures in the porta hepatis is necessary to ensure resectability prior to division of the hepatic parenchyma. The need to resect the hepatic duct in the future liver remnant far enough into the future liver remnant to ensure a negative bile duct margin means a more extensive dissection of the branches and the hepatic arteries. The likelihood of major vascular involvement of the future liver remnant and vascular reconstruction needs to be planned.

Brisbane nomenclature

Multiple terms have been used to describe liver resections: trisegmentectomy and trisectionectomy, lobectomy and hepatectomy have been used interchangeably, while the concepts segment, subsegment, sector, section, area and subarea became confusing after the integration of French, German and English literature. Since clear terminology and classification are necessary for accurate communication, the Brisbane nomenclature of Hepatic Anatomy and Resections was established in Brisbane in 2000 at a consensus meeting sponsored by the International Hepato-Pancreato-Biliary Association. This nomenclature has been adopted worldwide. The Brisbane nomenclature is anatomically correct, consistent, self-explanatory, precise, concise and translatable, and ensures agreement on anatomical and surgical terms. The term section is preferred to sector and the term hemiliver is used instead of lobe. Nomenclature is classified by first-, second- and third-order division anatomy.

First-order division

Hemiliver-oriented resections

First-order division anatomy refers to the division of the liver into right and left hemilivers along the mid-liver plane; right and left hemihepatectomy are the surgical terms. The left hemiliver includes segments 2–4, and the right hemiliver includes segments 5–8. The caudate lobe (segments 1 and 9) is not included in either hemiliver; if it is resected, it should be included in the description. The mid-liver plane divides the two hemilivers between the centre of the IVC and the gallbladder fossa, closely following the course of the MHV. This plane of division is not a straight line and there is no external fissure associated with it. After both arterial and portal right hemiliver inflow is occluded, an irregular line of demarcation can be drawn between the two hemilivers, usually in the form of a reversed question mark (¿).

Arterial anatomy

The left hemiliver arterial inflow is provided by two arteries: the segment 4 artery (A4; sometimes described as the middle hepatic artery) and the left hepatic artery, which provides arterial inflow for segments 2 (A2) and 3 (A3; Fig. 62.4 ). A4 usually crosses the ventral side of the pars transversa of the LPV (84% of patients); it may cross the left intersectorial plane from left to right after originating from an aberrant left hepatic artery (13%), or cross the mid-liver plane from right to left after originating from the right anterior hepatic artery (3%). A4 may arise from the RHA (55%), from the LHA (30%) or the proper hepatic artery (PHA) (5%). Multiple A4s can be found in 10% of patients. The frequent origin of A4 from the RHA and PHA (70% of cases) leads to a complicated situation during donor evaluation for left hemihepatectomy because there is poor arterial cross-flow between A4 and the LHA, leading to the need for dual arterial reconstruction when A4 does not arise from the LHA.

Fig. 62.4, Arterial inflow to the left hemiliver. A–D , The left hepatic artery (LHA) provides inflow for segments 2 and 3 (A2 and A3). Its course is relatively constant as, regardless of having a normal or aberrant origin, it courses caudal and lateral to the umbilical fissure (92% of cases). E–G , Either the LHA or a segmental branch may have an aberrant course, crossing the umbilical fissure cranially from medial to lateral (the remaining 8% of cases). Segment 4 origin is highly variable and can originate from the right hepatic artery (A, E, F and G), the LHA (B), an aberrant LHA (C) or the right anterior hepatic artery (D). Its course is relatively constant, crossing the ventral side of the pars transversa of the left portal vein (84% of patients); uncommonly, it crosses the umbilical fissure from left to right (13%; C) or crosses the mid-liver plane from right to left after originating from the right anterior hepatic artery (3%; D). Abbreviations: aLHA, aberrant left hepatic artery; rLHA, replaced left hepatic artery.

The right hemiliver arterial inflow is normally provided by two arteries, the right anterior and posterior sectorial arteries ( Fig. 62.5 ). These arteries originate from the RHA, which crosses left to right behind (75–88%) or in front of the common bile duct/common hepatic duct (CBD/CHD; 8–25%). The RHA courses lateral to the CBD and CHD without crossing in 4% because it originates from either the gastroduodenal artery or the superior mesenteric artery. Rarely, the RHA can originate from the coeliac trunk or directly from the aorta; in these cases, it courses behind the bile duct and the main portal vein. Regardless of the number of arteries and/or their origin, arterial structures to the right of the CHD and above the cystic duct can generally be divided during a right hemihepatectomy for cancer. The exception to this rule is the exceedingly rare variation where the proper hepatic artery bifurcates laterally to the CHD and the entire arterial inflow of the left hemiliver originates to the right of the CHD with the right anterior hepatic artery (RAHA).

Fig. 62.5, Arterial inflow to the right hemiliver. The right hepatic artery provides inflow to all segments. A–D , Regardless of its origin and variations, all arterial inflow to the right hemiliver lateral to the common hepatic duct can be safely divided. E , The exception is a rare detoured left hepatic artery that branches lateral to the common hepatic duct and provides the right anterior hepatic artery. The origin of the right hepatic artery is the proper hepatic artery (A); aberrant origins include the superior mesenteric artery (C), the gastroduodenal artery (D), the coeliac trunk and the aorta. The right hepatic artery generally bifurcates after crossing the common hepatic duct, either anteriorly (D) or posteriorly (A, C and E). Infrequently, the right hepatic artery may bifurcate at the level of the common hepatic duct before crossing it (B). Dotted lines signify the point of transection of the artery if a right hepatic resection is performed. Abbreviations: A2, segment 2 artery; A3, segment 3 artery; A4, segment 4 artery; A6, segment 6 artery; A7, segment 7 artery; GDA, gastroduodenal artery; LHA, left hepatic artery; RA, right anterior hepatic artery; RP, right posterior hepatic artery.

During right hemihepatectomy for living donation, the identification of extrahepatic sectorial and/or segmentary/subsegmentary branches (seen in 66% of cases) is crucial to preserve the arterial inflow to the graft. Extrahepatic sectorial branches may be encountered in up to 33% of cases. Extrahepatic segmentary or subsegmentary arteries (either A6 or A7) may occur in 35% of cases. These arteries may bifurcate lateral to the CHD, or posterior or medial to the CHD. On occasion, medial bifurcation of the RHA results in an RAHA anterior to the CHD and a right posterior hepatic artery (RPHA) posterior to the CHD. During living donor right hemihepatectomy, dissection of the RHA medial to the CHD is associated with an increased risk of biliary complications in the donor, and dissection is therefore limited to the lateral aspect of the CHD; anatomical variations leading to multiple right hepatic arteries to the right of the CHD may require multiple arterial reconstructions in the recipient. During left and extended left hemihepatectomy for cholangiocarcinoma, an RHA crossing posterior or anterior to the CHD may be invaded by cholangiocarcinoma, which may result in the need for vascular reconstruction.

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