Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_869_Библиотеки_им_академика_М_И_Перельмана.pdf
Total Hindgut Mesenteric
Mobilization fortaTME
J.CalvinCoey andRishabhSehgal
34
Introduction
The hindgut refers to the intestine distal to the
junction between the second and third part of the
transverse colon. Hindgut mobilization refers to
detachment of the hindgut from its surrounding
attachments. This alone is not enough to enable
its resection. To enable resection, the mesentery
that is contiguous with the hindgut must be also
detached, and any analysis of good-quality
colorectal resections will show that most operative time is spent in mobilizing the mesentery
[1–5]. In contrast, division and reconstitution of
the intestine can be rapidly achieved, once the
mesentery has been adequately released.
The importance of the mesentery in hindgut
mobilization stems from the embryological
development of both mesentery and intestine.
During development, the mesentery arises rst,
and the intestinal tube gradually takes shape at
the mesenteric periphery, receiving cellular and
connective tissue inputs from the mesentery.
Once the mesentery and intestine have assumed
their nal position within the abdominal cavity,
J. C. Coffey (*)
University Hospital Limerick and University of
Limerick, Department of Surgery and Graduate
Entry Medical School, Limerick, Ireland
e-mail: calvin.coffey@ul.ie
R. Sehgal
University Hospital Limerick, Department of Surgery,
Limerick, Ireland
the mesentery becomes attached to the posterior
abdominal wall. This is mediated by the peritoneal reection at the periphery of the digestive
system, by Toldt’s fascia between mesentery and
posterior abdominal wall and by vascular points
of connectivity such as the inferior mesenteric
artery [6, 7].
Hindgut mobilization requires that the mechanisms by which the mesentery and intestine are
held in position are disrupted. The peritoneum
must be incised and the plane between the mesentery and fascia disrupted by separating both
[8–11].
This chapter contains an explanation of the
anatomical and surgical foundation underpinning
total hindgut mobilization during taTME.
Fortunately, the anatomical basis is the same for
this as it is for visceral surgery everywhere from
the esophagogastric to the anorectal junction, and
so the same anatomical principles apply throughout. This means the technical requirements are
the same at all levels from transverse mesocolon,
through splenic exure, left mesocolon, mesosigmoid and mesorectum.
The following will commence with a brief
overview of the development of the technique by
which the hindgut is mobilized for taTME.It is
followed by a detailed description of the anatomical basis of the technique. Some references will
be made to the embryological development of the
hindgut, but a detailed description of that aspect
is beyond the scope of this chapter. The chapter
© Springer Nature Switzerland AG 2019
S. Atallah (ed.), Transanal Minimally Invasive Surgery (TAMIS) and Transanal Total Mesorectal
Excision (taTME), https://doi.org/10.1007/978-3-030-11572-2_34
357
358
J. C. Coey and R. Sehgal
will then include a description of the surgical
technique involved followed by a summary of the
current status of different technical platforms.
History
Until recently, mesenteric anatomy was considered complex. As the anatomy of the peritoneum
is determined by the mesentery, it follows that
peritoneal anatomy was also considered complex
[12–14]. The main reason for this is that the mesentery was described as being made up of multiple separate regions (or “mesenteries”)
(Fig. 34.1). This dogma dominated almost all
anatomical, surgical, radiological and other
appraisals of mesenteric anatomy [13, 15]. As the
mesentery is a pivotal structure for the intestinal
surgeon, it follows that technical descriptions
related to the mesentery, the peritoneum and
underlying fascia, lacked a formal anatomical
foundation.
Mesenteric mobilization was dogmatically
summarized along the following lines. The White
Line of Toldt (if present) was identied and used
as a landmark at which to commence division of
the peritoneum. The mesentery was then
“stripped” back to the midline, in order to facilitate division of the vessels within it. The mesentery was then divided up to the intestine, which in
turn was divided [16–20].
Most intestinal surgeons on both sides of the
Atlantic were long aware of the importance of
mesenteric mobilization. Jamieson and Dobson,
in the United Kingdom, emphasised this as far
back as 1909 [14, 21]. In 1942 Congdon et al.
Fig. 34.1 Depiction of classic model of mesenteric and
intestinal anatomy. According to this model, multiple
mesenteries attached directly to the posterior abdominal
wall. A mesentery was not normally found associated with
the ascending and descending colon
34 Total Hindgut Mesenteric Mobilization fortaTME
359
emphasised the importance of the mesentery in
saying that American surgeons generally got into
a particular plane and mobilized along this, with
minimal blood loss [22]. Still the anatomical
foundation remained unchanged in reference literature (Fig.34.1).
The importance of the mesenteric basis of
oncological surgery was identied by RJ Heald
in 1982 [23–25]. Heald spent a considerable
amount of time convincing the surgical community about the importance of mesenteric, fascial
and peritoneal anatomy, in describing the technique which he called total mesorectal excision
[26–33]. This coincided with the emergence of
laparoscopic means of conducting intestinal surgery. With this, surgeons were afforded a 20-fold
magnication of anatomical landmarks and high
resolution imaging of these. The new degree of
separation between surgeon and tissues (i.e. surgeons no longer directly held tissue) meant their
anatomical approach had to be based on an accurate model. While this was the case, the details of
one such model remained elusive and, in fact,
were largely ignored. Surgeons learned how particular patterns of activities permitted goodquality mesenteric-based surgery, without having
an anatomical correlate for these.
In 2012 our group claried the anatomy of the
mesentery [34]. We showed that it is a continuous
structure from the duodenojejunal exure to
anorectal junction [1, 5, 12, 15, 34–40]. This was
followed by an update in Gray’s Anatomy,
thereby reversing over 150years of dogma relating to the attachment of the small intestinal mesentery [41].
The original quote from the textbook that would
become Gray’s Anatomy (circa 1858) stated:
“It’s root, the part connected with the vertebral column, is narrow, about six inches in length, and
directed obliquely from the left side of the second
lumbar vertebra to the right sacroiliac symphysis.”
[42] The updated description in the 41st edition of
Gray’s Anatomy now states:
The mesocolon extends along the entire length of
the colon and is continuous with the small bowel
mesentery proximally and the mesorectum
distally… [43].
Mesenteric continuity is a simple property
with major implications. These are increasingly
emerging as the systematic characterization of the
mesentery gathers momentum. For example, it is
now recognized that the mesentery is not simply a
double fold of peritoneum that holds the intestine
in place but rather a collection of tissues that
maintains all abdominal digestive organs in position and in continuity with other systems. Once
the mesenteric frame and associated organs adopt
their nal position, the peritoneal reection develops around the digestive system to hold all in
position (Fig.34.2). In addition, certain regions of
the mesentery are anchored to the posterior
ab
Fig. 34.2 The peritoneal reection: (a) digital depiction
of the reection where the small intestinal mesentery
reaches the posterior abdominal wall and continues as the
right mesocolon. The reection is the translucent
membrane of peritoneum that bridges the gap between the
posterior abdominal wall and the mesentery. (b) Similar
view to that presented in (a) of the reection where the
small intestinal mesentery continues laterally as the right
mesocolon. The reection has been partially divided
360
J. C. Coey and R. Sehgal
ab
Fig. 34.3 Toldt’s fascia. The fascia has been coloured
green. (a) Image demonstrating Toldt’s fascia after the
right colon and mesocolon have been detached from the
posterior abdominal wall via mesofascial separation. (b)
abdominal wall, with Toldt’s fascia interposed
between both (Fig.34.3) [44, 45].
Perhaps the most important implication of
mesenteric continuity is that surgeons can formally depart from the peritoneal-based model of
surgical anatomy and adopt a mesenteric-based
and more accurate model. It is not surprising, that
an appraisal of the technical approach to hindgut
mobilization will reveal that the surgical community had long ago adopted the mesenteric model
over the peritoneal one.
Nomenclature
Any textual description of a surgical activity (i.e.
taTME with its multiple operative steps) requires
a set of specialized terms. For example, division
of the peritoneal reection is called peritonot-
omy. Separation of the mesentery from the underlying fascia is called mesofascial separation [37,
38, 46–53].
As the terms describe the surgical disruption
of anatomy, they must be anatomical in their derivation and meaning. This in turn requires that the
anatomical foundation on which they are based
must be accurate.
Image demonstrating Toldt’s fascia after the left colon and
mesocolon have been detached from the posterior abdominal wall via mesofascial separation
Such a set of terms was lacking until recently,
due largely to the erroneous classical model of
mesenteric and peritoneal anatomy [5, 13, 15,
38]. Clarication of mesenteric and peritoneal
anatomy has meant that a set of anatomically
accurate and sensible terms can be generated.
Examples are those described above (i.e. perito-
notomy and mesofascial separation).
The terms routinely used throughout the rest
of this chapter are dened in the next section.
While these may not be widely used throughout
the rest of this book, they are increasing in general and international adoption [5, 13, 15, 47, 54].
The set of terms is a utility of considerable importance as it enables authors and surgeons to accurately describe a technical activity. In addition,
the components of the set are intuitive, which
further improves the ability of the reader to
understand the concepts described, by providing
detail in an entirely anatomic-based manner.
Since any operation is made up of multiple individual activities happening either in sequence or
in tandem, appropriate terminology enables a
comprehensive description of hindgut mobilization in general [8–11, 55]. Adoption of this
anatomical- based approach permits a rigorous
standardization of the operation, irrespective of
the platform used to achieve it.
34 Total Hindgut Mesenteric Mobilization fortaTME
361
Denitions andTerminology
• Hindgut: intestine and mesentery from distal
transverse colon (mesocolon) to anorectal
level.
• Mesentery: the organ that maintains all
abdominal digestive organs in position and in
continuity with systems of the body.
• Peritoneal reection: The bridge of perito-
neum that occurs between abdominal wall
peritoneum and organ, wherever an organ
comes into close proximity with the abdominal wall.
• Plane: A plane is the conceptual zone between
two contiguous (i.e. touching) and continuous
surfaces.
• Mesofascial plane: conceptual zone between
mesentery and underlying fascia.
Comment This is arguably the most important
plane in colorectal surgery. It occurs throughout
and is of considerable technical importance.
• Toldt’s fascia: The areolar connective tissue
that occurs between an organ and the posterior
abdominal wall, whenever an organ comes
into close contact with the abdominal wall.
• Mesofascial separation: Separation of components that make up the mesofascial plane.
Comment The components that generate the
mesofascial plane are the mesentery and underlying fascia. Mesofascial separation refers to separation of the mesentery from the underlying
fascia. It is a critical activity required to achieve
mesenteric (and hence intestinal) detachment.
Detachment is required before mesenteric disconnection can be achieved.
• Peritonotomy: Division of the peritoneal
reection.
Comment
when one rst inspects the abdominal cavity one
cannot visualize the mesofascial plane. In order
This is a crucial activity in so far as
to expose this plane, the peritoneal reection
must rst be divided.
• Attachment: Mechanism of anchorage of
regions of the mesentery to the posterior
abdominal wall.
• Detachment: Separation of the mesentery
from the posterior abdominal wall.
• Disconnection: Complete separation of the
mesentery from the body.
Anatomy
The mesentery is continuous; this means the
mesentery of transverse colon continues as that
of the left colon (i.e. the left mesocolon)
(Fig. 34.4). The left mesocolon then continues
distally as the mesosigmoid and the continuation
of the mesosigmoid is the mesorectum [1, 5, 12,
15, 34, 35].
The term hindgut traditionally referred to the
intestine only, as the mesentery was previously
regarded as absent in certain regions (including at
the left mesocolon). In the following the “hindgut” is taken to refer to both intestine and mesen-
tery from the splenic exure distally (Fig.34.5).
The mesorectum terminates at an apex just above
the pelvic oor. This is the distal anatomical termination of the mesentery. The proximal termination of the abdominal mesentery is at the
esophagogastric junction [1, 5, 12, 15, 34, 35].
The left mesocolon is attached to the posterior
abdominal wall and Toldt’s fascia occurs between
it and the abdominal wall [1, 5, 12, 15, 34, 35,
56]. The same applies for the medial aspect of the
mesosigmoid. The lateral aspect of the mesosigmoid is not attached and is mobile. As a result, if
one were to follow the mesosigmoid from medial
to lateral, one would observe that the medial
region is attached while the lateral region is
detached (Fig.34.6) [1, 5, 12, 15, 34, 35, 56].
The medial and lateral regions of the meso-
sigmoid then converge at the rectosigmoid function to continue as the mesorectum. This is
362
ab c
Right mesocolon Left mesocolonTransverse mesocolon
Fig. 34.4 The mesentery (current model). (a) Anterior, (b) anterolateral and (c) posterior view
J. C. Coey and R. Sehgal
Fig. 34.5 The left mesocolon. (Taken from Chap. 2, “Mesenteric and peritoneal anatomy”. In Mesenteric Principles of
Gastrointestinal Surgery: Basic and Applied Principles)
Left mesosigmoidal peritoneal reflection
White line
connective tissue
Anterior collar of mesorectum
“Mid” mesorectum
34 Total Hindgut Mesenteric Mobilization fortaTME
363
conned to the posterior and lateral aspects of
the upper and mid-rectum (Fig. 34.7). At the
level of the distal rectum, the mesorectum continues around anteriorly and forms a collar or
cuff of mesorectum (Fig.34.8) [1, 5, 9, 12, 15,
34, 35, 56–59].
There are three major mechanisms by which
the mesentery (and hence the abdominal digestive system itself) is maintained in position.
These are central, intermediate and peripheral.
Sigmoid colon
of Toldt
Left iliac
fossa
Fig. 34.6 The lateral aspect of the mesosigmoid. (Taken
from Chap. 2, “Mesenteric and peritoneal anatomy”. In
Mesenteric Principles of Gastrointestinal Surgery: Basic
and Applied Principles)
Centrally, the mesentery is suspended at the inferior mesentery artery origin. Peripherally, the
mesentery is suspended by formation of the
reection. In between both, Toldt’s fascia is an
intermediate mechanism of attachment. These
mechanisms of attachment develop during
embryological growth and must be disrupted during colorectal surgery on the hindgut. They are
separately described in the following [1, 5, 9, 12,
15, 34, 35, 56–59].
Pelvic side wall
Mesorectum
Fig. 34.7 Axial view of the mesorectum viewed from
above down. (Taken from Chap. 2, “Mesenteric and peritoneal anatomy”. In Mesenteric Principles of Gastrointestinal
Surgery: Basic and Applied Principles)
Fig. 34.8 Sagittal view
of the mesorectum.
(Taken from Chap. 2,
“Mesenteric and
peritoneal anatomy”. In
Mesenteric Principles of
Gastrointestinal Surgery:
Basic and Applied
Principles)
Mesorectum
Toldt’s
fascia
Waldeyer’s
fascia
364
peritoneal
Cecum
Ileum
ab
J. C. Coey and R. Sehgal
The mesorectum is attached/anchored to the
pelvic side wall via a continuation of Toldt’s fascia between it and the pelvis. The fascia continues between the mesorectum and adjacent
structures, towards the pelvic oor where it condenses to form the so-called Waldeyer’s fascia.
Waldeyer’s fascia is not a separate fascia, but
rather it is a continuation of Toldt’s fascia [1, 5,
9, 12, 15, 34, 35, 56–59].
Anterior to the mesorectum, the fascia is also
interposed between the mesorectum and anterior
structures. In males, these anterior structures are
the seminal vesicles and prostate, while in
females they are the cervix and vagina. Toldt’s
fascia continues around the posterolateral aspect
of the mesorectum to occupy the position between
the mesorectum and anteriorly located structures.
This region of the fascia has been called
Denonvilliers’ fascia. As with Waldeyer’s fascia,
Denonvilliers’ is not a separate fascia, but rather
a continuation of Toldt’s fascia [1, 5, 9, 12, 15,
34, 35, 56–59].
The peripheral mechanism by which the mesentery is held in position is the peritoneum.
Wherever an organ comes into close contact with
the posterior abdominal wall, the peritoneum
“leaves it” to reach across to the organ and bridge
the space between the organ and the posterior
abdominal wall. This is the peritoneal reection
and it is of considerable surgical importance
(Fig.34.9) [1, 5, 6, 9, 12, 15, 34, 35, 56–59].
The reection is continuous around the
entirety of the mesentery and intestine. It is present at the lateral aspect of the descending colon.
It continues from here along the lateral aspect of
the mesosigmoid, in the region where the mesosigmoid separates away from the posterior
abdominal wall to become mobile [1, 5, 6, 9, 12,
15, 34, 35, 56–59]. A reection of the peritoneum
also occurs at the medial aspect of the mesosigmoid and left mesocolon, in the region of the
abdominal midline (Fig.34.10). From the duodenojejunal exure, this reection continues caudally along the medial aspect of the left mesocolon
and then along the medial aspect of the mesosigmoid, to reach the upper mesorectum and rectum
[1, 5, 6, 9, 12, 15, 34, 35, 56–59].
The reection at the medial aspect of the
mesosigmoid continues caudally along the right
side of the mesorectum where it is termed the
right pararectal reection. The reection at the
lateral aspect of the mesosigmoid continues dis-
Right
peritoneal
Right
reflection
White line
of Toldt
Fig. 34.9 The peritoneal reection: (a) digital depiction
of the reection where it bridges the space between the
posterior abdominal wall and the right side of the colon.
(Taken from Chap. 2, “Mesenteric and peritoneal anatomy”. In Mesenteric Principles of Gastrointestinal
Surgery: Basic and Applied Principles). (b) Similar view
reflection
Toldt’s fascia
to that presented in (a) in a cadaveric setting. The reection has been divided sharply using a scalpel. Submesothelial connective tissue is apparent beneath the
surface of the reection. (Taken from Chap. 2, “Mesenteric
and peritoneal anatomy”. In Mesenteric Principles of
Gastrointestinal Surgery: Basic and Applied Principles)
ab
34 Total Hindgut Mesenteric Mobilization fortaTME
Sigmoid colon
365
Fig. 34.10 The peritoneal reection at the medial border
of the mesosigmoid: (a) Digital depiction of the reection
where it bridges the space between the posterior abdominal wall and the mesosigmoid viewed from above and
from left to right. (Taken from Chap. 14, “The appearance
of the mesentery during open surgery”. In Mesenteric
Principles of Gastrointestinal Surgery: Basic and Applied
tally along the left lateral aspect of the mesorectum where it is termed the left pararectal
reection. In the mid-pelvic region, the right and
left pararectal regions of the reection come
around anteriorly to form the anterior reection
of the peritoneum. This is true end of the peritoneal cavity [1, 5, 6, 9, 12, 15, 34, 35, 56–59].
The inferior mesenteric artery (IMA) branches
ventrally from the abdominal aorta, proximal to
its bifurcation and enters the sigmoid mesentery.
As the IMA enters the mesentery, it is surrounded
by a sheath of connective tissue that is continuous
with Toldt’s fascia and that also receives contributions from the connective tissue of the
mesentery into which the vessel is incorporated
[1, 5, 6, 9, 12, 15, 34, 35, 56–59].
As the fascia is located between the mesentery
and the posterior abdominal wall, it provides a
useful landmark for the abdominal surgeon. The
mesenteric domain of the abdomen is located
anterior to the fascia, while the non-mesenteric
domain is located posterior to the fascia. Posterior
to the fascia are retroperitoneal structures such as
the kidneys, the ureters, and gonadal vessels.
Toldt’s fascia thus separates the mesenteric and
non-mesenteric domains of the abdomen.
Principles). (b) Digital depiction of the reection where it
bridges the space between the posterior abdominal wall
and the mesosigmoid viewed from above down in the
midline. (Taken from Chap. 14, “The appearance of the
mesentery during open surgery”. In Mesenteric Principles
of Gastrointestinal Surgery: Basic and Applied Principles)
Importantly, it is not necessary to excavate
through the fascia to identify underlying structures [1, 5, 6, 9, 12, 15, 34, 35, 56–59].
The nal point to be mentioned relates to the
colonic exures [5, 10, 12]. There are numerous
exures, but the ones that exert the greatest challenge are the hepatic and splenic. The exures are
best understood as comprising four components
centred on a central mesenteric component
(Fig. 34.11). At each exure, the mesentery
changes from attached to non-attached and thus
undergoes considerable conformational changes.
The mesenteric component of the exures can be
considered in terms of a longitudinal component
and a radial component. The radial component of
the splenic exure extends from the middle colic
origin. At the middle colic, it is xed in position
to the mesenteric root region, and as one extends
along the radial axis, the mesentery detaches to
become mobile. The longitudinal axis of the
transverse mesocolon extends from the transverse mesocolon (where it is mobile) to the left
mesocolon (where it is attached) [1, 5, 10, 12].
The other components of the exures are the
peritoneum, colon proper and fascia. The fascia
is interposed between attached regions of
366
Intestinal
l
a
b
J. C. Coey and R. Sehgal
Intact
c
Fascial
component
of flexure
component
of flexure
d
Colofascia
separation
Mesenteric
component
Peritoneal
component
e
Mesenteric
component
of flexure
Fig. 34.11 The splenic exure. (Taken from Chap. 20,
“Mesenteric component of exural mobilisation”. In
Mesenteric Principles of Gastrointestinal Surgery: Basic
and Applied Principles). (a) The intact splenic exure. (b)
Flexure conceptually disconnected from non-exural
regions. (c) View of the remaining non-exural mesentery
after removal of the exure. Colic, mesenteric, fascial and
peritoneal components are apparent. (d) View from the
Peritoneal component
of flexure
Peritoneal
component
left side, after conceptually removing the exure. The
reection has been divided through to demonstrate the
relationship between the peritoneum, colon, mesentery
and fascia. (e) View of the in situ exure if the non- exural
regions of the intestine and mesentery were removed. The
view demonstrates the relationship between the colon,
mesentery, reection and fascia