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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_819_Библиотеки_им_академика_М_И_Перельмана
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a
Anterior sectoral duct
PV
sectoral du
ct
A
6.3 Anomalies ofBile Ducts Draining theRight Hemiliver
b
III
VIII
V
I
VII
HD
Posterior
sectoral duct
Fig. 6.2 (a) Hjortsjo Crook. (b) Magnetic resonance cholangiopancreatogram showing Hjortsjo Crook
t
I
VI
HD
CHD
LHD
HA
H
LHA
H
LPV
6.3.2 Absence ofRight Hepatic Duct
45
The absence of the right hepatic duct is an anatomical variation that results during development.
There are three anatomical variations in which the anterior
and posterior sectoral ducts do not form the right hepatic
duct, thus resulting in absence of the right hepatic duct
(Fig.6.4 shows the incidences of these anomalies): This paragraph is reprinted from: W.Y.Lau, Hilar Cholangiocarcinoma.
Springer, 2013. ISBN 978-94-007-6472-9.
The anomalies which can result in absence of the right
hepatic ducts are:
6.3.2.1 Shifting oftheEntry oftheRight Bile
Duct Inferiorly
This set of anomalies involves the insertion of the right bile
duct, or one of its branches, inferiorly into the biliary tree at a
lower point than the prevailing site of conuence (Fig. 6.5).
This paragraph is reprinted from: W.Y. Lau, Hilar
Cholangiocarcinoma. Springer, 2013. ISBN
978-94-007-6472-9.
Low union may affect the main right bile duct, a sectoral
right duct (usually the anterior one and this anomaly results in
absence of right hepatic duct), a segmental duct, or a subsegmental duct. The duct unites with the common hepatic duct
below the prevailing site of conuence, or in about 2% of
patients, unites rst with the cystic duct and then with the
common hepatic duct. These anomalies place a greater risk of
Fig. 6.3 Hjortsjo Crook and its clinical signicance
46
A
A
Bc
6 Intrahepatic Glissonian Triad: Anatomy Relevant toLiver Resection andLiver Transplantation
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P
P
A
P
A
P
Bc
A
P
A
P
A
P
Bc
Fig. 6.4 Variations in the anatomy of the right hepatic duct and their incidences, based on analysis of liver casts. A anterior sectoral branch, P
posterior sectoral branch, Bc bile duct conuence
P
6.3 Anomalies ofBile Ducts Draining theRight Hemiliver
47
ductal injury during laparoscopic cholecystectomy. This paragraph is reprinted from: W.Y.Lau, Hilar Cholangiocarcinoma.
Springer, 2013. ISBN 978-94-007-6472-9.
6.3.2.2 Trifurcation ofBile Duct
When performing a right hemihepatectomy, a left hemihepatectomy, an anterior right sectionectomy, a right posterior sectionectomy, a right trisectionectomy or a left
trisectionectomy, a stricture is likely to develop at the
Fig. 6.5 Shifting of entry of right bile duct inferiorly
biliary trifurcation site if no normal biliary safety margin
is left at the site of the transection. It is always safer to
divide the biliary tree with a safety margin of at least
1cm from the site of the biliary confluence (Fig. 6.6).
This paragraph is reprinted from: W.Y. Lau, Hilar
Cholangiocarcinoma. Springer, 2013. ISBN
978-94-007-6472-9.
6.3.2.3 Anterior or Posterior Sectoral Branch
Joining theLeft Hepatic Duct
The right posterior sectoral duct inserts with the left bile duct
in 20% of patients and the right anterior sectoral bile duct
does so in 6%. In both cases, there is no right hepatic duct as
both join the left duct, one to the left of the midline and the
other in the midplane. A right sectoral bile duct inserting into
the left bile duct to the left of the midplane is in danger of
injury during left hepatectomy. Therefore, in the left
hepatectomy, the left bile duct should be divided close to the
umbilical ssure so as to avoid injury to a right sectoral duct.
If the left duct is divided at the normal site of conuence of
the right and left hepatic ducts, the right sectoral duct can be
injured (Fig.6.7). It is good practice to obtain an intraoperative
cystic duct cholangiogram when performing a left
hepatectomy to detect this anomaly. Please take note that
even with these anomalies, a right hepatectomy is safe. This
paragraph is reprinted from: W.Y. Lau, Hilar
Cholangiocarcinoma. Springer, 2013. ISBN
978-94-007-6472-9.
A
Fig. 6.6 Trifurcation of bile duct. A right anterior sectoral branch, B right posterior sectoral branch
A
P
48
B8
7
t
t
B8
5
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B7
B
ncorrec
incorrect
correc
correct
6 Intrahepatic Glissonian Triad: Anatomy Relevant toLiver Resection andLiver Transplantation
B7
B5
B6
6
Fig. 6.7 Separate entry of right anterior and right posterior sectoral ducts (no right hepatic duct)
B6
B5
B
The surgically important anomalies of the left ductal sys-
6.4 Anomalies ofBile Ducts Draining
theLeft Hemiliver
tem involve variations in the site of insertion of B4 (Fig.6.8b),
multiple ducts coming from B4 (Fig.6.8c), and the primary
union of B3 and B4 with subsequent union of B2 (Fig.6.8d).
The left hepatic duct has a much longer extrahepatic course
than the right bile duct. Normally, a 2–3cm length of the left
hepatic bile duct is in an extrahepatic position.
The prevailing pattern of bile duct drainage from the left
liver is shown in Fig.6.8a and is present only in 30% of
individuals. Thus, variations are present in the majority of
individuals.
The segmental ducts from segments 2 and 3 (B2 and B3,
respectively) unite to form the left lateral sectional duct. This
duct passes behind the umbilical portion of the portal vein
and unites with the duct from segment 4 (B4), also called the
left medial sectional duct. The union of these ducts to form
the left hepatic duct occurs about one-third of the distance
between the umbilical ssure and the conuence of the left
and right bile ducts.
B4 may join the left lateral sectional duct to the left or right
of its point of union in the prevailing pattern (Fig.6.8b). In
the former case, the insertion may occur at any place to the
right of the prevailing location up to the point where the left
lateral sectional duct unites with the right bile duct. In the
latter instance, which according to Couinaud, is present in
8% of individuals, there is no left hepatic duct, instead the
common hepatic duct is formed by the conuence of three
ducts—the right hepatic duct and two left hepatic ducts (B4
and the left lateral sectional duct).
The commonest variations in the left bile duct are: Type 1,
common joining of B2 with B3, B4 then joins near to the left
hepatic duct; Type 2, common joining of B4, B3 and B2 near
to the same point; and Type 3, common joining of B4 with
B3 (Fig.6.9).
B3
B2
left later al section duct
n
t
4
3
t
t
t
6.4 Anomalies ofBile Ducts Draining theLeft Hemiliver
49
ab
B3
left later al
left later al
B2
B3
B
dc
combined B3, B4 duct
ombined
3, B4 duc
B4
B4
B4
4
B
B4
sectional bile du
sectional bile duct
left bile duct
left bile duc
B4
B2
left later al sectio
B3
B4
B2
left later al
eft later al
sectional bile duct
sectionalbile duc
left hepalic duct
left hepalic duc
Fig. 6.8 Variations in formation of left hepatic ducts. (a) Prevailing pattern of left bile duct. (b) Insertion of B4 shifted to right or left. (c) Multiple
ducts draining B4. (d) B3, B4 form common channel before insertion of B2
50
Anterior sectoral vein
P
B2
abc
3
3
2
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B4
B
LHD
HD
Fig. 6.9 Common variations in the anatomy of the left bile duct. (a) Common Joining of B2, 3 Type 1. (b) Common joining of B2, 3, 4, Type 2.
(c) Common joining of B3, 4 Type 3
6 Intrahepatic Glissonian Triad: Anatomy Relevant toLiver Resection andLiver Transplantation
B4
B4
B3
B
B2
B
HD
LHD
B3 B3
B
B2
B
B4
LHD
HD
Common type 3-branch type
A
Fig. 6.10 Variations in the anatomy of the right portal vein (analysis of liver cast). A Anterior sectoral branch. P Postterior sectoral branch
The left hepatic duct runs at a variable angle. In some
individuals, it is almost horizontal, but in others, it runs
sharply upward. It is much easier to expose a long length of
duct in the former type.
The prevailing pattern of bile ducts draining the caudate
A
P
P
revealed three principal portal vein branching patterns in the
hilar area (Fig.6.10):
Kida etal. reported that variations in the anatomy of the
biliary tract are mostly (81%) associated with variations in
the anatomy of the portal vein.
joining to the left
portal vein type
A
lobe has been described in detail in Chap. 3.
6.6 Portal Vein andLiver Resections
6.5 Variations inAnatomy ofthePortal
Vein Branches intheHilar Area
Few variations are found in the major portal vein branches
because the portal vein develops during the very earliest part
of the gestational period. Reports by three investigators
How the portal vein and the hepatic veins divide the liver into
hemilivers, sections/sectors and segments has been described
in detail in Chap. 2. On the right side of the liver, the portal
vein division corresponds exactly to those of the hepatic
artery and bile duct. On the left side of the liver, arteriobiliary
Ligamentum teres
2
a
6.6 Portal Vein andLiver Resections
51
segmentation differs from portal vein segmentation. The left
portal vein consists of a transverse and an umbilical portion.
The transverse portion sends only a few small branches to
segment 4 and one or two branches to segment 1. All larger
branches from the portal vein to the left liver arise exclusively beyond the attachment of the ligamentum venosum,
i.e. from the umbilical portion of the vein (Fig.6.11).
The umbilical portion of the portal vein has a unique pattern of ramication. The pattern is similar to an airconditioning duct that sends branches at the right angle from
both of its sides to supply rooms (liver segments). On the
right side usually more than one branch pass to segment 4.
On the left side usually, one branch goes to segment 2, but
more than one branch to segment 3. The left portal vein terminates where it joins the ligamentum teres at the free edge
of the liver (Fig.6.11). The explanation for this unique struc-
ture of the umbilical portion of the left portal vein is that it is
adapted to a dual function: in utero, it acts as a conduit
between the umbilical vein and the ductus venosus
(Fig.6.12), a conduit in which blood ows towards the duc-
7
6
Fig. 6.11 The portal vein and its intrahepatic branches. MPV main
portal vein, RPV right portal vein, RASBV right anterior sectoral portal
vein, RPSPV right posterior sectoral portal vein, U umbilical portion of
left portal vein, T transverse portion of left portal vein
8
5
RPSPV
RPSPV
RASBV
RASBV
4
MPV
MPV
RPV
RPV
T
Ligamentum venosum
igamentum venosum
3
U
U
b
Fig. 6.12 (a) Magnetic resonance imaging showing ductus venosus (D) in a 25 weeks foetus. (b) Magnetic resonance imaging showing ductus
venosus (D) and umbilical vein (U) in a 35-week foetus
52
Splenic vein
reverse flow after birth
Hepatic portion of
Ductus venosus
lenic vein
n
n
e
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Fig. 6.13 Portal venous
blood ow in utero
6 Intrahepatic Glissonian Triad: Anatomy Relevant toLiver Resection andLiver Transplantation
inferior vena cava
Hepatic vain
patic vain
(right vitelline)
t vitelline)
Portal vein
ortal vei
Hepatic vein
Hepatic vein
e
Segment of vin with
rev
mesenteric vei
Sup-mesenteric vein
tus venosus (Fig.6.13); in adult life, it acts as a conduit for
portal vein supply to the left liver, and blood ows in the
reverse direction from the ligamentum venosum towards the
ligamentum teres (Figs.6.14 and 6.15). It is for this reason
that the umbilical portion of the portal vein is like an airconditioning duct. It is also because its branching pattern on
the left side of the liver is so structurally different from the
branching pattern on the right side so that we have the different terms of sector and section on the left side while the term
sector is equivalent to section on the right side of the liver.
It is uncommon to have variations of the portal vein division. Probably the most common is the right anterior sectoral
vein joins to the left portal vein (see Sect. 6.5) while the right
posterior sectoral vein originates independently from the
main portal vein. When this occurs, the anterior sectoral vein
Left umbilical
vein
is usually quite high in the porta hepatis and may not be
obvious. An unsuspecting surgeon may divide the posterior
sectoral vein, thinking that it is the right portal vein, and will
consequently be confused when the anterior sectoral vein is
come upon during hepatic transection carried out for right
hepatectomy. In the left hepatectomy, the anterior sectoral
portal vein may inadvertently be damaged, resulting in ischaemia to liver segments 5 and 8.
Another less common portal vein anomaly is trifurcation
of the right anterior sectoral vein, right posterior sectoral
vein and the left portal vein at the hilum. Again to avoid
subsequent stricture developing in the portal vein that is left
after liver transection, a safety margin of at least 1cm should
be left at the transection plane. A rare but potentially
devastating anomaly is the absent extrahepatic left portal
Umbilical arteries
Pulmonary
Ductus venosus
6.6 Portal Vein andLiver Resections
53
Fig. 6.14 Blood circulation
in utero
Pulmonary vein
Ductus arteriosus
IV
Superior
vena cava
Pulmonary vein
Crista dividens
Oval foramen
artery
II
Inferior vene cava
Descending
aorta
I
Sphincter in
ductus venosus
Inferior vene cava
Portal
vein
Umbilical
vein
54
Descending
Medial umbilical ligament
Pulmonary artery
vene cava
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Fig. 6.15 Blood circulation
after birth
6 Intrahepatic Glissonian Triad: Anatomy Relevant toLiver Resection andLiver Transplantation
Ligamentum
arteriosum
Superior
vena cava
Closed
oval
foramen
Inferior
Pulmonary
vein
Ligamentum teres
hepalis
aorta
Portal
vein
Sup. vesical artery
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