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a
2 Surgical Anatomy ofthePancreas
9
PSPDA; however, as there is a branch leading to the papilla
of Vater can be conrmed while preserving ASPDA, it is
creas. The AIPDA shallowly runs through the pancreatic
parenchyma in the pancreatic uncinate.
nourished by ASPDA.
2.1.1.4 Dorsal Pancreatic Artery (DPA)
Posterior Inferior Pancreatoduodenal Artery (PIPDA)
andAnterior Inferior Pancreatoduodenal Artery
(AIPDA)
Normally, IPDA branches into PIPDA and AIPDA, and the
PIPDA runs from the posterior fascia of the pancreas to the
upper right side of the pancreatic parenchyma to join the
PSPDA.Both PSPDA and PIPDA run through the posterior
fascia of the pancreas on the posterior surface of the pan-
LGA
CHA
In a PD, when the pancreatic head is transected in front of the
portal vein, the DPA is present in the residual pancreas.
However, if a PD is performed when a tumor is present near
the SMA because of the cancer of the pancreatic head, in
some cases, the pancreatic head may be resected in front of
SMA.In such cases, it is necessary to pay attention to where
DPA runs through. In an examination of DPA branch morphology using MDCT (Fig.2.2), 40% of cases were reported
b
LGA
CHA
SPA
DPA
DPA
40%
c
CHA
LGA
SMA
DPA
SPA
d
CHA
25.7%
LGA
DPA
SPA
CA
SPA
20%
Fig. 2.2 Variation in the origin of the dorsal pancreatic artery. SPA splenic artery, CHA common hepatic artery, SMA superior mesenteric artery,
LGA left gastric artery, CA celiac artery, D PA dorsal pancreatic artery. Inferior pancreaticoduodenal artery (referred from Ref. 4)
8.6%
10
to branch from the splenic artery, 25.7% from the common
hepatic artery, and 20.0% from the SMA [3]. After ligation
of the IPDA and GDA, which are inow arteries, arterial
bleeding may be observed from the cranial stump of the pancreas during pancreatic dissection. In such cases, an arcade is
considered to be formed between the DPA and
GDA.Therefore, it is important to determine branch morphology in situations where it is necessary to deal with DPA
in advance.
2.2 The Veins ofthePancreatic Head
During PD, the duodenum may become congested. If the
outow veins are ligated before the pancreatic head inow
arteries are ligated, the pancreatic head and duodenum will
become congested and the amount of intraoperative bleeding
will increase.
Therefore, it is important to have complete understanding
of the anatomy of pancreatic head veins. The gastrocolic
trunk is an important vein in the pancreatic head that is often
encountered by surgeons during PD and surgery for gastric
or colon cancer, and it is difcult to perform subsequent procedures if bleeding occurs. Henle [6] reported in 1868 that
the right anterior colonic vein and the right gastroepiploic
vein formed a common duct, which is referred to as Henle’s
gastrocolic trunk and ows into the superior mesenteric vein
(SMV). The common trunk that ows into the SMV is
referred to as Henle’s venous trunk, and the trunk that ows
from that area into the ileocolic vein is called the surgical
trunk. When performing a right hemicolectomy, it is important to bear this venous anatomy in mind. The anterior superior pancreatoduodenal vein (ASPDV), which ows into the
right colonic vein and the right gastroepiploic vein, runs
across the anterior surface of the pancreas, becomes the anterior inferior pancreaticoduodenal vein (AIPDV), forms an
arcade, and nally ows into the SMV.The posterior superior pancreatoduodenal vein (PSPDV) is a vein of the second
part of the duodenum and the pancreatic bile duct that runs
through the bile duct or the posterior surface of the pancreas
and into the primary duct of the portal vein. The posterior
inferior pancreatoduodenal vein (PIPDV) is a vein of the
duodenal papilla and is downstream from the duodenum. It
directly ows in the rst jejunal vein or the SMV (Fig.2.3).
In certain cases, PSPDV and PIPDV can form arcades.
Takamuro et al. [7] mentioned that PSPDV and PIPDV in
certain cases form arcades while in others they do not.
The inferior mesenteric vein (IMV) most commonly
merges with the SMV; however, the second most common
type merges with the splenic vein. Other types ow into the
conuence of the SMV and the splenic vein. If pancreatic
cancer invades the conuence of the SMV and the splenic
vein, splenic vein dissection is required. Although in most
A. Horiguchi et al.
Fig. 2.3 Inferior pancreaticoduodenal vein. PIPDV posterior inferior
pancreaticoduodenal vein, AIPDV anterior inferior pancreaticoduodenal vein
cases it is not necessary to reconstruct the splenic vein, in
some rare cases, splenomegaly may occur because of intraoperative spleen congestion. Therefore, it is extremely
important to ascertain the IMV inow site using preoperative
MDCT.
2.3 Surgical Techniques
2.3.1 Treitz Ligament Approach forArteryFirst PD
Using this approach, the transverse colon is cranially lifted
while the retroperitoneum, which is just above the Treitz
ligament, is incised to identify the rst jejunal artery and the
middle colic artery as well as expose the SMA trunk.
Releasing the Treitz ligament as much as possible will facilitate IPDA ligation. Passing a tape attached to the origin of
the SMA from the right hand side of the opening of the Treitz
ligament to the left hand side facilitates the identication of
SMA and IPDA orientation. The inferior mesenteric vein
(IMV) is often reported on the left side of the SMA trunk
(the left cranial side of the Treitz ligament), which can limit
the identication of the IPDA and is dissected in such cases.
When dissecting the inferior margin of the pancreatic head
toward the origin of the SMA, the IPDA can be identied in
the origin of the middle colic artery (MCA) on the central
dorsal side. It is ligated twice after identication. Although
an approach from the left side offers a good eld of view, it
2 Surgical Anatomy ofthePancreas
11
is possible to approach from the right side in cases with less
adipose tissue. Because there are multiple variations, such as
cases in which the IPDA branches from the rst jejunal
branch (Fig. 2.4a, b), directly bifurcates from the SMA
(Fig. 2.5a, b), and bifurcates separately before the SMA
(Fig.2.6a, b), preoperative identication is important. After
dealing with inowing arteries of the head of pancreas to
prevent the congestion of the pancreatic head and the duode-
a
FJA
IPDA
num, and associated persistent bleeding, the upper jejunum
is dissected and pulled to the right. Tunneling of the portal
vein is performed and the pancreas is sharply dissected with
a scalpel. The vein owing from the excised side of the pancreas to the SMV is ligated and dissected, and then PD is
performed. Although with conventional PD, the pancreatic
duodenum becomes congested during the procedure and
becomes swollen in certain cases, which increases the
b
IPDA
FJA
Fig. 2.4 IPDA+FJA type (a: 3D angiogram of MD-CT, b: the intraoperative photograph). IPDA inferior pancreaticoduodenal artery, FJA rst
jejunal artery, IPDA inferior pancreaticoduodenal artery
a
IPDA
b
IPDA
Fig. 2.5 IPDA independent type (a: 3D angiogram of MD-CT, b: the intraoperative photograph). IPDA inferior pancreaticoduodenal artery
12
ab
PIPDA
PIPDA
AIPDA
AIPDA
Fig. 2.6 AIPDA/PIPDA independent type (a: 3D angiogram of MD-CT, b: the intraoperative photograph). PIPDA posterior inferior pancreatico-
duodenal artery, AIPDA anterior inferior pancreaticoduodenal artery
A. Horiguchi et al.
amount of bleeding. With an IPDA-approached PD, bleeding
at this point is reduced and the procedure can be performed
with peace of mind. For laparoscopic surgery, the caudal
eld of view is extremely good, indicating that procedures
where it is usually difcult to obtain a good eld of view
when performed using laparotomy can be performed from
the front. Furthermore, the magnifying effect facilitates the
easy identication of SMA (Fig.2.4).
As cases where the PIPDA and AIPDA branch separately
are often complicated, the procedure must be carefully performed while conrming the location of arteries and veins
using preoperative MDCT imaging. In each case, it is important to be familiar with the branching morphology prior to
surgery. Horiguchi et al. conrmed the IPDA from the left
hand side, carried out ligation and taped it, and then after
dissecting the jejunum, they pulled out the IPDA to the right
hand side past the posterior side of the SMA and the portal
vein, and subsequently conrmed the IPDA again at the pancreatic hook before performing double ligation to thoroughly
remove the lymph nodes around the SMA.
Treitz ligament approach is a useful method of reducing the
amount of bleeding that makes it easy to detach veins that
run from the pancreatic head to the SMV.
The artery-rst approach was rst reported by Sanjay etal.
in 2012 [1]. There are multiple ways to approach SMA.In
1993, Nakao etal. [9] reported a mesenteric approach, which
is considered to be the world’s rst artery- rst PD.In 2007,
Horiguchi etal. [2] reported that the left- sided approach from
the SMA was useful for dealing with IPDA.However, the
concept of artery-rst PD is used in laparoscopic PD.In 2011,
the authors reported on the rst case of robot-assisted laparoscopic PD in Japan [10, 11]. Nagakawa et al. reported a
method of dealing with the IPDA from the right side of the
SMA during laparoscopic PD [12]. This is a useful method
for safely dealing with the jejunal veins from the right side of
the SMA. Sugiyama et al. reported an intestinal derotation
procedure for easily dealing with IPDA, which involves performing complex pancreatic head and duodenal dissection by
derotating the pancreatic head and duodenum [13].
The vascular anatomy of the pancreatic head is complex
and gaining a preoperative understanding using MDCT is
extremely useful.
2.4 Discussion
The IPDA presents with various branching patterns [8].
Horiguchi etal. [3] roughly classied these into three different types based on MDCT imaging: a type that directly
branches from the SMA, a type that forms a common trunk
with the rst jejunal artery, and a type that branches from the
right hepatic artery of the SMA. Artery-rst PD using the
2.5 Conclusion
In future, it is expected that the number of cases of laparoscopic PD as well as PD by laparotomy will increase and
ascertaining the vascular structure of the pancreatic head is
extremely important to safely perform PD.
2 Surgical Anatomy ofthePancreas
13
References
1. Sanjay P, Takaori K, Govil S, Shrikhande SV, Windsor JA.
‘Artery-rst’ approaches to pancreatoduodenectomy. Br J Surg.
2012;99:1027–35.
2. Horiguchi A, Ishihara S, Ito M, Nagata H, Shimizu T, Furusawa
K, etal. Panceatoduodenectomy in which dissection of the efferent
arteries of the head of the pancreas is performed rst. J HepatoBiliary- Pancreat Surg. 2007;14:575–8.
3. Horiguchi A, Ishihara S, Ito M, Nagata H, Asano Y, Yamamoto T,
etal. Multislice CT study of pancreatic head arterial dominance. J
Hepato-Biliary-Pancreat Surg. 2008;15:322–6.
4. Horiguchi A, Ishihara S, Ito M, Asano Y, Furusawa K, Tsuda K,
et al. Vascular anatomy of the pancreas head region. Tan to Sui.
2011;32:1143–8.
5. Horiguchi A, Ishihara S, Ito M, Asano Y, Yamamoto T, Miyakawa
S, et al. Three-dimensional models of arteries constructed using
multidetector-row CT images to perform pancreatoduodenectomy
safely following dissection of the inferior pancreaticoduodenal
artery. J Hepato Biliary Pancreat Sci. 2010;17:523–6.
6. Henle J.Handbuch der systematischen Anatomie des Menschen.
Druck und Verlag von Friedrich Vieweg und Sohn. 391. Braun schweig.1868. (cited by ref. 7 Gillot etal. 1964).
7. Takamuro T, Oikawa I, Murakami G, Hirata K. Venous drainage
from the posterior aspect of the pancreatic head and duodenum.
Okajimas Folia Anat Jpn. 1998;75:1–8.
8. Bertelli E, Di Gregorio F, Bertelli L, Civeli L, Mosca S.The arterial
blood supply of the pancreas: a review. III.The inferior pancreaticoduodenal artery. An anatomical review and a radiological study.
Surg ZRadiol Anat. 1996;18:67–74.
9. Nakao A, Takagi H. Isolated pancreatectomy for pancreatic head
carcinoma using catheter bypass of the portal vein. HepatoGastroenterology. 1993;40:426–9.
10. Horiguchi A, Uyama I, Miyakawa S. Robot-assisted laparoscopic pancreaticoduodenectomy. J Hepatobiliary Pancreat Sci.
2011;18:287–91.
11. Horiguchi A, Uyama I, Ito M, Ishihara S, Asano Y, Yamamoto
T, et al. Robot-assisted laparoscopic pancreatic surgery. J
Hepatobiliary Pancreat Sci. 2011;18:488–92.
12. Nagakawa Y, Hosokawa Y, Sahara Y, Takishita C, Nakajima T,
Hijikata Y, etal. A novel “artery rst” approach allowing safe resection in laparoscopic pancreaticoduodenectomy: the uncinate process rst approach. Hepato-Gastroenterology. 2015;62:1037–40.
13. Sugiyama M, Suzuki Y, Nakazato T, Yokoyama Y, Kogure M, Abe
N, etal. Intestinal derotation procedure for facilitating pancreatoduodenectomy. Surgery. 2016;159:1325–32.
Surgical Anatomy oftheBiliary Tract
EduardoOliveraPertusso, JoaquinGarcia,
andLuisRusoMartinez
3
Abstract
The anatomical aspects of the biliary tract and its vascularization are of special surgical interest. The area of
Glisson’s capsule (hilar plate) that surrounds the vasculobiliary structures of the hepatic hilum has a great importance, as well as the crossed arterial vascularization that
allows the supply ow, during the injuries of the main
hepatic arteries.
Anatomical variations in the origin of the superior biliary conuent, the cystic duct, and its relationship with the
cystic artery are determinants of the aspect of the triangle
of Calot and keys for safe cholecystectomy and avoiding
surgical injuries to the bile duct.
The length of the left hepatic duct allows a wide exposure that facilitates to make of the hepatic jejunal anastomosis, associating the Hepp-Couinaud maneuver.
The so-called hepatic pedicle is formed by the common bile duct, the portal vein, with the hepatic artery. Its
structure is practically constant, but in 15% of cases the
right hepatic artery is located in front of the main bile
duct.
This chapter describes the anatomical structure of the
biliary tract, morphological patterns, most important variations, and the relevant aspects of its vascularization.
variants, and the most important aspects of its vascularization, based on current knowledge [1–13].
The biliary tree is formed by a system of ducts of progressively higher caliber that conduct the bile secreted by the
liver to the duodenum. It originates in microscopic canaliculi
in the hepatic parenchyma, in which the walls are formed by
hepatocytes.
From a topographic point of view, the biliary tree can be
divided into an intrahepatic biliary tract and an extrahepatic
one. The latter is formed by the common hepatic and the
choledochus, the main biliary tract, and an accessory biliary
tract, namely the gallbladder and the cystic duct.
There are three fundamental aspects from the surgical
point of view:
(a) The variations in the formation of the superior biliary
conuent, key to perform a correct oncologic hepatic
surgery.
(b) The anatomic variations related to the cystic duct and its
relationship with the cystic artery are determinant of the
position of the triangle of Calot and also very important
for a safe cholecystectomy.
(c) The arterial vascularization at the level of the hilar plate
allows to sustain a substitution ow, in case of lesions of
the main hepatic arteries (right and left).
3.1 Introduction
Precise knowledge of the anatomy of the biliary tree is critical to obtain optimum results in hepatobiliary surgery and to
avoid surgical lesions of its conducts.
In this chapter, we describe the anatomic structure of the
biliary system, its morphologic patterns, the most important
E. O. Pertusso · J. Garcia · L. R. Martinez (*)
School of Medicine, University of Republic (UdeLar),
Montevideo, Uruguay
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022
M. Makuuchi et al. (eds.), The IASGO Textbook of Multi-Disciplinary Management of Hepato-Pancreato-Biliary Diseases,
https://doi.org/10.1007/978-981-19-0063-1_3
3.2 Intrahepatic Biliary Tract
The intrahepatic bile ducts are part of the portal triad and are
surrounded by an invagination of the Glisson’s capsule.
Next, there are branches of the portal vein, whose nomenclature is based on the consensus of Brisbane in the year 2000.
The hepatic parenchyma is divided into two by the line of
Cantlie which goes from the fossa vesicae to the right edge
of the inferior vena cava. The bile of each hemiliver is
drained by the right and left hepatic ducts that join at the
level of the hilar plate to form the superior biliary conuent,
from which the common hepatic duct originates.
15
16
E. O. Pertusso et al.
3.2.1 Right Hepatic Conuent andIts
Anterior andPosterior Branches
The right hepatic duct is short (0–23mm) and vertical, and
its way is external to the hepatic parenchyma. It is formed by
the conuence of the sectoral posterior and anterior right
ducts, which drain bile of the segments 6–7 and 5–8,
respectively.
The posterior sectoral duct has a horizontal and anteriorposterior direction. It is longer than the anterior sectoral
duct, and it is located above it. It ends joining the posterior
surface of this duct after crossing the superior surface of the
anterior branch of the right portal vein, although in 20% of
the cases, it may run under this portal branch.
The anterior sectoral duct is vertical, and it is located in
front and to the left of the anterior branch of the right portal
vein. In 20% of the cases, it is retroportal. It receives the
canaliculi of the segments 5 and 8; however, these may present variations (segment 8 may drain in the posterior sectoral
duct or segment 5in the right hepatic duct, the posterior sectoral duct or the common hepatic duct).
3.2.2 Left Hepatic Conuent andIts Auents
a bilateral drainage, and the ducts ow out in the posterior
surface of the right and left hepatic ducts, next to the biliary
conuence. In 15% of the cases, the drainage is exclusively
to the left hepatic duct, while only 5% is exclusively to the
right hepatic duct.
3.2.4 Accessory Biliary Ducts
Initially described by Luschka, they are thin ducts usually
originating in the right lobe and drain subsegmentary areas
of hepatic parenchyma and also drain in intrahepatic ducts,
in the right hepatic duct or the common bile duct. The subvesical duct is the most frequent one (30–35%), and it runs
between the visceral surface of the liver and the superior surface of the gallbladder. Sometimes there is a network of
aberrant biliary canaliculi which ends in a cecum end point
in the fossa vesicae, and they drain in the hepatic ducts. They
are a frequent cause of bilirrhage post cholecystectomy,
which justies the clipping and ligation of the internal and
inferior sector of the gallbladder bed.
Less frequent is the presence of an aberrant biliary duct
that drains from the liver straight to the gallbladder.
The left hepatic duct is longer than the right one (20–50mm),
and it has a horizontal pathway, running behind the posterior
margin of the quadrate lobe. Initially located above and
behind the left portal vein, it crosses its superior surface to
locate itself in front of the transverse portion of that vein. It
has a long path in the hepatic hilum, where it is located outside the parenchyma. This long extrahepatic path has surgical importance because it allows to have a better dominion
and exposure of the left hepatic duct, key to the performance
of a wide hepatic jejunal anastomosis by the maneuver of
Hepp-Couinaud.
The left hepatic duct receives the bile from the segments
2, 3, and 4, which converge usually in stages in a common
duct. The duct of the segment 2 is superior and oblique,
while one of the segment 3 is wider and it has a concave
pathway, its conuence is usually to the left of the round
ligament.
The bile from segment 4 is usually collected by four
ducts, two superior ones and two inferior, which drain in
the left hepatic duct through a common duct, but they may
drain all or some of them independently in the left hepatic
duct.
3.2.3 Biliary Drainage ofSegment 1
The caudate lobe drains through 1 to 6 ducts which are
located underneath the portal branches. In most of them exist
3.2.5 Biliary Conuence andIts Variations
The right and left hepatic ducts converge in the hepatic
hilum, where they are surrounded by the biliary plate, a
thickening of the Glisson’s capsule that wraps the vascularbiliary structures, adhering to the walls of the biliary tract
and making its dissection difcult. There are three sectors:
the gallbladder plate (in front of the gallbladder), the umbilical plate, in relation to the left biliary tree, and the hilar plate
in front of the superior biliary conuence. Its knowledge is
key to the surgical approach of the hepatic hilum. The tissue
of the hilar plate gets in the hepatic parenchyma surrounding
the elements of the portal triad, while downwards it is in continuity with the hepatoduodenal ligament and the minor
omentum (Photo 3.1).
In its usual conguration (68%), the common bile duct is
formed by the conuence of the right and left hepatic ducts
outside the hepatic parenchyma, in front and slightly to the
right of the right branch of the portal vein. The anatomic
variations of the superior biliary conuence are not rare and
are dominated by the high incidence of variations in the outlet of the right sectoral posterior duct.
In 18% of the cases, the right sectoral ducts converge
jointly in the left hepatic duct giving place to the triple conuence or trifurcation of the biliary tract. When this happens, the
right posterior sectoral branch is usually located above the
anterior sectoral branch, and there is not a hepatic duct as
such.
a
3 Surgical Anatomy oftheBiliary Tract
17
b
c
d
Photo 3.1 Biliary conuence and its variations. (a) Modal congura-
tion. (b) Triple conuence or trifurcation of the biliary tract. (c)
Aberrant right posterior duct. (d) Right posterior duct drains in the left
In 8% of the cases, one of the right sectoral branches, usually the posterior one, drains in the posterior surface of the
left hepatic duct, forming an acute triangle. In these cases,
hepatic duct. Arrow head: left hepatic duct. Fine Arrow: Right posterior
duct. Thick arrow: Right anterior duct.
The segmentary canaliculi of both lobes may drain in the
common biliary duct independently, a fact that is known as
“convergence étagée” or staggered conuence.
the left hepatic duct drains the bile of the left hemiliver and
the anterior sector of the right one.
In 6% of the cases, the right posterior sectoral duct has
3.3 Extrahepatic Biliary Tract
an aberrant pathway and can converge in the right hepatic
duct, the common biliary duct at a variable distance of the
superior biliary convergence, and even in the superior edge
of the cystic duct. This morphologic variation is an important risk factor for biliary surgical lesion during
cholecystectomy.
The hepatic hilum originates the common hepatic duct, and
it is called, arbitrarily, choledochus after receiving the mouth
of the cystic duct. The cystic choledochus union or inferior
biliary conuent takes place at a variable distance of the convergence of the hepatic ducts, so is better to call common
18
E. O. Pertusso et al.
biliary duct at the continuity of the common hepatic duct and
the choledochus duct.
From a topographic point of view, the common bile duct
may be divided into three portions: a supraduodenal portion,
where it is part of the hepatic pedicle, a retroduodenopancreatic portion located behind the rst portion of the duodenum
and the head of the pancreas, and an intramural portion
where it transits in the duodenum wall to debouch in the
major duodenal papilla.
3.3.1 Supraduodenal Portion: Hepatic
Pedicle
This portion runs from the origin of the common biliary duct
to the crossing of the superior margin of the rst portion of
the duodenum. This sector becomes evident during the dissection of the hepatic hilum when descending to the superior
and elevating the visceral surface of the liver, since both the
organs are in touch in their anatomic position (Photo 3.2).
At its origin, the common biliary duct transits in the free
margin or “pars acida” of the minor omentum, between two
visceral peritoneal sheets and surrounded by an independent
fascia that allows its individualization during the surgical
exploration.
It is located upfront the portal vein, slightly to the right,
with the proper hepatic artery at its left. The relation to the
portal vein is practically constant, although there are reports
of cases where the main biliary tract was retroperitoneal.
Usually the proper hepatic artery is divided into its two
terminal branches next to the inferior edge of the liver, and
its right branch goes behind the common bile duct, between
this and the portal vein. In 15% of the cases, the right hepatic
artery is located upfront the main biliary tract.
In case of the existence of an aberrant right hepatic artery
or a common hepatic artery originated from the superior
mesenteric artery, these arteries may have a retroportal pathway and be located in the right margin of the bile duct.
3.3.2 Retroduodenopancreatic Portion
The retroduodenopancreatic portion extends from the crossing
with the superior margin of the rst portion of the duodenum
to the duodenal wall. In this segment, the common bile duct
becomes a retroperitoneal organ, separated from the anterior
surface of the inferior vena cava by the fascia of Treitz. The
maneuver of Kocher- Vautrin allows the decollation of this fascia and access the posterior surface of the duodenum–pancreas
to approach the retropancreatic choledochus.
As it descends, the common bile duct relates to the posterior surface of the rst portion of the duodenum and with the
head of the pancreas, where most of the times, it is covered
by a ap of pancreatic tissue or entirely surrounded by the
glandular parenchyma. In 12% of the cases, its posterior surface is bare.
In its retropancreatic pathway, the common bile duct
describes a double curvature backwards and to the right, to
debouch in the second portion of the duodenum. At this
point, it separates from the portal vein, which runs left
where its origin is located, in the espleno-mesenteric conuence. The portocholedochal triangle is delimited at the
origin of the gastroduodenal artery and its posterosuperior
pancreatic- duodenal branch. This branch runs in front of
the bile duct while its homonymous vein is located behind.
Both of them originate multiple branches of ne caliber,
branches that vascularize the biliary tract and the
duodenum–pancreas.
Photo 3.2 Hepatic pedicle. Supraduodenal portion. CHA common
hepatic artery, GDA gastroduodenal artery, RHA right hepatic artery,
LHA left hepatic artery, PV portal vein, LPV left portal vein
3.3.3 Intramural Portion
In this portion, the common bile duct runs obliquely through
the duodenum wall to debouch in the major duodenum
papilla at the level of the second portion of the duodenum, in
the union of the posterior wall, and medially in 80% of the
cases. In the rest, the common bile duct may debouch in the
third portion or in the second duodenal knee. As it runs
through the duodenal wall, it runs by a fenestra in the proper
muscle layer named duodenal window.
Usually, the bile duct and the main pancreatic duct join in
one common duct of 1–12mm in length and 4.4mm in caliber, which opens in the vertex of the major duodenal papilla.
3 Surgical Anatomy oftheBiliary Tract
19
This morphology, named “anatomy of Opie” is what lets us
explain the physiopathology of the acute lithiasic pancreatitis. In 70% of the cases, the common duct is dilated, and it is
called ampulla of Vater.
Sometimes, both the ducts end independently in the major
duodenal papilla after a short parallel pathway, with the oricium of the common bile duct located above and to the left
of the main pancreatic duct. Less frequently, we can nd an
independent ending of both ducts in different places of the
duodenum.
In the distal extreme of the main pancreatic duct and the
bile duct, there is a complex sphincteral system described by
Ruggero Oddi, formed by the circular and longitudinal
smooth muscle bers with a ne nerve and humoral regulation. Boyden described it more precisely, and nowadays,
three main components are recognized: the choledochal and
pancreatic sphincters, which surround the distal sector of
each duct, and the ampullary sphincter that surrounds the
common duct when this is present.
3.4 Vascularization oftheMain Biliary
Tract
Contrary to the hepatic parenchyma that receives a double
vascularization, arterial and portal, the vascularization of the
biliary tract depends exclusively of the arterial vascularization. The arterial vascularization of the biliary tract is very
rich at the level of the hilum, retroduodenopancreatic and
intramural, but it is poorer in its supraduodenal portion,
which is the most vulnerable sector for ischemia and stenosis
during the surgical manipulation.
3.4.1 Vascularization oftheBiliary
Conuence
upward and downward pathway, which anastomose each
other through transversal channels. Two thirds of the arterial
vascular input comes from the upward branches originated in
the posterosuperior pancreaticoduodenal, supraduodenal,
gastroduodenal, and retroportal arteries, while the remaining
third of the input comes from the downward branches originated in the right and left hepatic arteries, and the cystic one.
Rarely, the proper hepatic artery gives direct branches to the
common bile duct.
In the right and left margins of the common bile duct,
the two predominant arteries are identied, named left and
right marginal arteries or arteries of the hours 3 and 9,
respectively, which justies the longitudinal performance
of the choledochotomy. In occasions, a third dominant
artery may be found in the posterior surface or artery of the
hour 6.
The retroduodenopancreatic segment of the common bile
duct is vascularized by many branches of the posterosuperior
pancreatic–duodenal artery, responsible for the vascularization of this segment, and the retroportal artery.
The venous drainage of the common bile duct originates
in a epicholedochal plexus located in the surface of the common bile duct that drains in the veins of the paracholedochal
plexus, formed by parallel vessels to the bile duct which
organize themselves into two marginal veins known as the
veins of the hours 3 and 9, existing in exceptional cases a
marginal vein of the hour 6.
The marginal veins drain in the gastric veins, the posterosuperior pancreaticoduodenal ones, and in the gastrocolic
trunk. Upwards, they communicate with the hilar venous
plexus, which is tributary of the portal branches of the caudate lobe and segment 4. This complex venous system allows
to develop a portal vicariant circulation, in cases of thrombosis of the portal vein, dilating and prompting the entity called
portal cavernoma.
The ducts of the biliary conuence receive their vascularization from a rich arterial plexus formed by branches of the
right and left hepatic arteries and the cystic artery, which join
forming an extrahepatic arterial arcade named caudate
arcade. Apart from irrigating the bile ducts, this arterial network serves as a way of collateral interlobular arterial circulation from which the arterial substitution network is
stablished when there is a unilateral lesion of the hepatic
arteries.
3.4.2 Vascularization oftheCommon
BileDuct
The supraduodenal common bile duct is vascularized by 6–8
arteries of ne caliber of longitudinal disposition and an
3.4.3 Vascularization oftheMajor Duodenal
Papilla
The arterial vascularization of the major duodenal papilla is
given by straight vessels which originate in the anterior and
posterior pancreaticoduodenal arcades, formed by the anastomosis of the branches of the gastroduodenal and inferior
mesenteric artery. Of these, the posterosuperior pancreaticoduodenal artery is the main input.
From both arcades, straight vessels originate that approach
the papilla in a variable number, and two stand out: one
artery of the hour 9 o’clock, originated in the posterior
arcade, and one artery of the hour 3 o’clock originated in the
anterior arcade. This determines a “safe area” of less vascularization between the hours 11 and 1 which is used to make
the incision in the sphincterotomy.