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Fig. 3.19 Mobilization of the left colon under the IMA ( green arrow depicts elevation of the pedicle and dashed arrow depicts direction of
dissection). Notice the relationship of the ureter to the gonadal vessels. With permission from Yuko Tonohira
Fig. 3.20 Dashed green line
depicts the posterior rectum,
while the blue and orange lines
represent the middle and anterior
compartments; the middle com-
partment is only present in
females
the IMA off the aorta. The lower rectum is innervated by
presacral nerves formed by the fusion of the lumbar splanchnic nerves and the aortic plexus. Subsequently, these nerves
combine to form the hypogastric plexus located just below
the sacral promontory (Figs. 3.29 and 3.30 ). The hypogas-
tric plexus gives rise to two main hypogastric nerves which
travel along the lateral sacrum and pelvic sidewalls into the
pelvic plexus located in the lower rectum adjacent to what
are typically conceived as the lateral stalks of the mesorectum [ 9 , 10 ].
The parasympathetic innervation of the rectum and anal
canal is comprised of sacral roots S2–4 and travels via the
pelvic splanchnic nerves known as the latter (nervi) (Fig. 3.25 ).
The nervi erigentes fuse with the sympathetic hypogastric
nerves at the pelvic plexus. From here the pelvic plexus gives
to the inferior mesenteric plexus and the periprostatic plexus.
The inferior mesenteric plexus distributes both sympathetic
and parasympathetic innervation to the lower rectum and
anal canal. The periprostatic plexus supplies the prostate,
seminal vesicles, vas deferens, urethra, ejaculatory ducts,
and bulbourethral glands [ 10 , 11 ].
Pelvic dissection poses a risk of injury to the pelvic nerves
with increased risk of trauma at certain locations. High ligation
of the IMA may lead to injury of the sympathetic preaortic
nerves. Similarly, development of the avascular plane between
the mesorectum and presacral fascia at the level of the sacral
3 Surgical Anatomy
35
Fig. 3.21 Pelvic anatomy highlighting the sacrum, hypogastric nerves,
and avascular alveolar space between the fascia propria and presacral
fascia
Anterior and Middle Compartments
The anterior compartment is largely comprised of the bladder and the adjacent paravisceral fat pad. The nerve-vessel
plate lies between the two structures. The middle compartment lies between the anterior and posterior compartment
and exists only in females. It is outlined by the endopelvic
fascia overlaying the uterus, vagina, and tuberosacral ligament (Fig.
3.22 ) .
Right Colectomy
With either approach, the patient is fi rst placed in a
Trendelenburg position with the operating table inclined
toward the left. The omentum is retracted by lifting and placing this superiorly over the transverse colon and liver. The
small bowel is then mobilized out of the pelvis and toward
the left side of the abdomen. These steps will help isolate the
terminal ileum, right colon, and mesentery from other vital
structures (Figs. 3.1 and 3.2 ).
Right Colectomy: Distinct Anatomy
of Medial-to- Lateral Mobilization
Fig. 3.22 Denonvilliers fascia can often be a diffi cult plane to identify;
careful tension/counter-tension between the rectum and the genitourinary structure will help develop the appropriate plane
promontory or the concavity of the sacrum exposes the superior
hypogastric plexus and the hypogastric nerves to injury. Trauma
at both levels results in sympathetic denervation with intact
parasympathetic innervation leading to bladder dysfunction
and retrograde ejaculation. As the dissection is extended caudally, the pelvic plexus may be damaged resulting in both
sympathetic and parasympathetic denervation. Injury at this
level can lead to rectal, urinary, and erectile dysfunction, vaginal dryness, and dyspareunia [ 12 ].
Pearl: The critical maneuver in performing a medial-to-
lateral dissection for right colectomy is creation of a
window around the origin of the ileocolic pedicle with
appropriate tension near the bowel and then protection of
the duodenum and other retroperitoneal structures during
ligation and subsequent dissection .
The right colon is supplied by the ileocolic artery branching off the superior mesenteric artery. Anatomically, it courses
just infero-caudally to the third portion of the duodenum. This
is best visualized by grasping either the cecum or mesentery
close to the bowel wall anteriorly or ventrally. In thinner
patients, identifi cation of the duodenal sweep or C curve can
be observed with superoanterior retraction of the transverse
colon. In some patients, this must be preceded by division of
congenital fusion attachments of the right colon mesentery to
the proximal transverse colon mesentery. With anterolateral
retraction of the ileocecal region, a tenting or bowstringing
effect will be noted—with the mesenteric vasculature acting
as the scaffold (Figs. 3.5 and 3.31 ). In general, when tracing
named mesenteric vascular structures, such as the ileocolic
vessels, to their origin, there will be a thinning out or paucity
of adiposity in the mesenteric fat on both sides of the vessels.
Careful dissection through the mesentery at this avascular
point is critical. This is generally fi rst performed by creating
an opening in the peritoneum and mesentery inferiorly and
then encircling the vessels superiorly. Some mobilization of
the mesocolon from the retroperitoneal structures may be nec-
36
Fig. 3.23 Schematic representation of the prostate, nerves, rectum,
and pelvic structures
T.D. Francone and R.G. Landmann
Fig. 3.24 Reverse “C-shaped” plane during distal anterolateral dissection along the pelvic side
essary and can be performed with gentle blunt sweeping
motions dorsally. When doing so, care must be taken to visualize the right ureter inferolaterally and, in particular, the duodenum posteriorly (Fig. 3.14a, b ). Once these structures are
well visualized and out of harm’s way, a high or central ligation can be performed. This can be done in a variety of ways
based on surgeon preference—endoscopic stapling devices,
energy devices, or application of clips with intermediary division. At this point, the mesocolon can be safely grasped ventrally, and the retroperitoneal attachments can be safely
dissected away from the right colon and its mesentery either
sharply or with gentle brush movements. In this plane, one can
see a thin white line of Toldt separating the retroperitoneal
structures from the remainder of the mesocolon. Care must be
taken to stay in the appropriate plane and not injure the duodenum or, more laterally, not mobilize the kidney (Fig. 3.32 ).
Pearl : ( 1) Identifi cation of the duodenum is a helpful marker
for confi rming the correct plane of dissection and extent of
dissection when performing the procedure for oncologic
lymph node staging. (2) The critical maneuver in performing
a medial-to-lateral dissection is to sustain proper tension and
counter-tension . Only by doing so will the surgeon be able to
identify and maintain the correct plane, allowing the procedure to continue along its natural progression .
A key point in performing this maneuver is to gently push
or sweep the peritoneal refl ection line down rather than pull
other structures down which generally causes more tearing
and subsequent bleeding. Further distal dissection of the mesentery is performed to the level of the middle colic vessels.
The middle colic vessel is the primary blood supply to the
proximal two-thirds of the transverse colon and branches off
the superior mesentery artery just inferior to and then overlies
the pancreas. Care must be taken to use precise technique in
this retroperitoneal space as the pancreaticoduodenal and gastroepiploic veins may cause signifi cant hemorrhage if excess
tension and shearing occur. Once the middle colic vessel is
identifi ed, the right branch of the middle colic vessel is then
divided after isolation. This can be done with gentle anterosuperior retraction of the transverse colon and consequent identifi cation of the takeoff of the right and left branches of the
middle colic—a classic “Y” pattern may be seen (Fig.
3.33 ).
3 Surgical Anatomy
Fig. 3.25 Entry into the presacral space involves retraction to
the left to expose the right pelvic
sidewall
37
Fig. 3.26 Medial mobilization of
the left colon demonstrating the
arterial blood supply, ureter, and
nerves
In the vicinity of the hepatic fl exure, the right colic vein,
located lateral to the right branch of the middle colic artery,
will be seen coursing from the pancreas to the hepatic fl exure.
This should also be carefully divided while preventing injury
to the gastroepiploic vessels. Generally, after identifying the
line of transection for the transverse colon, a window around
the right branch of the middle colic artery (and right branch of
middle colic vein) is created at the apex of the “Y” and is then
divided in a left-to-right fashion. The dissection can then be
extended inferiorly and proximally to mobilize the terminal
ileal mesentery and also superiorly and distally to divide the
mesentery to the level of the middle colic vessels. These latter
vessels are preserved in anticipation of anastomosis of the
small bowel to the transverse colon. At this point, the right
colon will now only be held in place by lateral avascular
attachments to the abdominal sidewall and then the hepatic
fl exure attachments and gastrocolic attachments of the omentum to the transverse colon. These can generally be easily
divided by either a dissecting energy device (ultrasonic or
bipolar type) or an energized, monopolar cautery/Metzenbaum
scissors. Dissection proceeds proximally dividing the hepatic
fl exure (Figs.
3.34 and 3.35 ) and again carefully avoiding the
38
T.D. Francone and R.G. Landmann
gastroepiploic vein and then the lateral attachments to the
ascending colon in a superior-to-inferior fashion into the pelvis while staying medial to the retroperitoneal structures, in
particular Gerota’s fascia. At the conclusion of the mobilization, one will have kept the retroperitoneal fascia intact and
dissected to the point of visualization of the preserved right
iliac vessels, right psoas muscle, and right ureter (Fig. 3.32a,
b ).
Pearl : Maintenance of dissection in the appropriate plane
and gentle dissection of the retroperitoneal refl ection away
from the target colon and mesentery allow for a safer and
more appropriate complete and intact oncologic resection
without invasion of the tissues .
Inferiorly, along the terminal ileal mesentery, there is a
refl ection noted at the attachment to the retroperitoneum
(Fig. 3.36 ). This fold is medial to the ureter, overlies the right
iliac vessels in the right pelvis, and is also superolateral to
the sacral promontory. If entered appropriately with anterior
retraction of the terminal ileum, this mobilization of the mesentery from the retroperitoneum can be performed sharply
without any energy-type devices and then continued superiorly and separating the mesentery of the terminal ileum and
right colon off the duodenum and pancreas as well.
Pearls :
1 . Leaving the lateral attachments to the abdominal sidewall
(line of Toldt) and hepatic fl exure until the very end of
dissection allows for appropriate scaffolding of the tissue
and aids in achieving counter-tension when necessary .
2 . When completing the detachment of these lateral attach-
ments, a visualization of a purple hue/discoloration will
be noted due to the previously dissected planes held in
place only by thin peritoneal tissue layers . This helps
demarcate the appropriate dissection line .
Fig. 3.27 The hypogastric plexus located just below the SP sacral
promontory; PSS presacral space
Fig. 3.28 Cross-sectional view
of the pelvis at the level of the
sacral promontory
3 Surgical Anatomy
Fig. 3.29 Dissection of the ileocolic pedicle from a medial
approach
39
Fig. 3.30 Medial-to-lateral mobilization highlighting the duodenum and white line of Toldt as the ascending colon and mesentery are ventrally
retracted
Right Colectomy: Distinct
Anatomy of Lateral-to- Medial
Mobilization
This approach is generally the easier dissection to learn
and perform. There are several critical anatomic landmarks
that, once appreciated, can lead to a safer, more expedient
and appropriate oncologic resection (sometimes termed total
Pearl : Lateral-to-medial mobilization provides the surgeon
the easiest transition to laparoscopic colectomy and also
helps in teaching others . Care must be taken to fi rst
approach and identify the ureter and fold of the terminal
ileal mesentery and its attachment to the retroperitoneum .
mesocolic excision—including the intact peritoneum encompassing the colon and mesenteric structures including high
ligation of the pedicles). With the exclusion of a right colectomy for pathological enlargement of the appendix (i.e.,
mucocele, cystadenoma, cystadenocarcinoma, or carcinoid),
Fig. 3.31 Depicts “Y” pattern of
middle colic vessels
Fig. 3.32 Hepatic fl exure mobilization highlighting the liver, gallbladder, duodenum, and hepatocolic ligament ( HF hepatic fl exure, GB
gallbladder)
Fig. 3.33 Mobilization of the
hepatic fl exure from the transverse colon
3 Surgical Anatomy
41
Fig. 3.34 Visualization of the ureter while mobilizing the cecum and
terminal ileum off the retroperitoneum. The ureter will course slightly
more laterally on the right crossing over the right external iliac artery
grasping this tubular structure can help signifi cantly in
retraction. Otherwise, either the terminal ileum or cecum can
be gently and carefully grasped to mobilize the enteral
structures anteriorly and toward the left upper quadrant. This
will then clarify the lateral attachments of the colon and mesentery to the retroperitoneum. Along the colon, this will be
the right lateral line of Toldt. Division of this will enter into
a loose alveolar plane, and then dissection can proceed distally along the ascending colon to the hepatic fl exure. In the
vicinity of the ileocecal valve, however, care must be taken
to identify and preserve the ureter as it crosses the right iliac
artery bifurcation (Figs.
3.14a, b and 3.16 ). Care should be
taken to stay within this appropriate plane and not too
l ateral—otherwise, entry into Gerota’s fascia or mobilization
of the kidney will ensue. Mobilization within the correct
plane of the mesocolon from the retroperitoneum centrally
(or medially) toward the takeoff base of the ileocolic pedicle
will also expose the anterior surface of the duodenum and
pancreas. The mesentery of the terminal ileum is then divided
from the retroperitoneum to the level of the right iliac vessels
as described above in the medial-to-lateral mobilization. At
this point, as noted in the medial-to-lateral mobilization, the
base of the ileocolic pedicle should now be easily visualized
and divided as above.
Fig. 3.35 Laparoscopic view of the lesser sac from patient’s right side
Fig. 3.36 Accessing the lesser
sac through the omentum (gastrocolic ligament)
Right Colectomy: Common Steps
The gastrocolic attachments to the transverse colon need to
be divided and then entry into the lesser sac is performed.
The surgeon will fi rst lift the omentum and retract this superiorly. Division can then be done sharply as the attachments
are generally avascular or otherwise easily controlled with
monopolar cautery or an energy device. For right colectomies, the distal extent of dissection is generally around the
falciform ligament or in line with the middle colic vessels. It
42
T.D. Francone and R.G. Landmann
is sometimes best to start at this point and work retrograde
toward the hepatic fl exure. At a certain point, the omentum
will then be fully mobilized. The lesser sac is entered and the
proximal transverse mesocolon can then be sharply dissected
from the other abdominal and retroperitoneal structures
(Figs. 3.37 and 3.38 ). In particular, the posterior leaf of the
omentum must be separated along its congenital attachments
from the mesocolon. Care must be taken to completely and
safely mobilize the mesocolon off of the duodenum and
pancreas. As noted above, this area will have some vascular
attachments that will need to be controlled. Another point of
entry into the lesser sac will be the fusion or attachment of
Fig. 3.37 Transverse colon anatomy
the gallbladder dome to the transverse colon or mesocolon.
Similarly to above, entry at this level will also expose the
lesser sac, and then one can proceed to mobilize the mesocolon off the duodenum. All that will remain at this point will
be the hepatic fl exure attachments, which should now be easily divided.
Once completely dissected, the right colon and mesentery
should be able to be mobilized and expressed as a midline structure. Division of the intestines and subsequent
anastomosis can now be performed either in a laparoscopic fashion intracorporeally or in an open fashion once
extracorporealized through an extraction incision. Details of
these techniques will be discussed in a later chapter.
Transverse Colectomy and the Middle Colic Vessels
Pearl : The critical maneuver in performing a transverse
colectomy is identifi cation of the middle colic artery and its
distal right and left branches . In addition, care should be
taken to prevent injury to the pancreas and right gastroepiploic vein . Ability to approach this from both sides of the
patient will contribute to success .
In cases requiring resection of the transverse colon, the
middle colic vessel will need to be ligated and divided,
sometimes in a high fashion (Figs. 3.39 and 3.40 ). This can
proceed as a progression of the above steps. However, rather
than isolating the right branch of the middle colic vessel, the
entire middle colic vessel may be divided. This can be iso-
Fig. 3.38 Middle colic vessels
3 Surgical Anatomy
Fig. 3.39 Dissection of the IMA
via a medial-to-lateral approach
43
Fig. 3.40 Laparoscopic hand-assist demonstrating the areolar plane
between the colon mesentery and the retroperitoneum; IMA inferior
mesenteric artery
Fig. 3.41 Anatomy of the left colon highlighting the IMA pedicle and
sacral promontory
lated by gently retracting the mesentery of the transverse
colon superiorly. The middle colic artery and its right and
left branches will be identifi ed. During dissection of the
transverse colon mesentery off the pancreas and before division of the middle colic vein, the right gastroepiploic vein
overlying the pancreas must be identifi ed and preserved. In
certain cases, the transverse mesentery may be divided as a
proximal progression during total (procto)colectomy. This is
generally done with the surgeon on the patient’s right side
after mobilization of the left colon. In this instance, after the
splenic fl exure is mobilized and divided, the transverse mesentery may then be serially ligated and divided in a retrograde fashion using an energy device. Alternately, a window
can be created around the middle colic vessels and divided in
an antegrade right-to-left fashion. This continues proximally
to divide either the middle colic artery or both right and middle colic branches.
Left Colectomy and Anterior Resection
Pearl : The critical maneuver in performing a medial-tolateral dissection is to sustain proper tension and countertension . Only by doing so will the surgeon be able to identify
and maintain the correct plane, allowing the procedure to
continue along its natural progression .
The patient is oriented in the Trendelenburg position with
the left side tilted up, which assists in displacing the small
intestine into the upper abdomen. This is an exceptional
opportunity to appreciate the pelvic anatomy in its entirety
before starting one’s dissection. Take a moment to understand
the multiple compartments of the pelvis including the relationship of pelvic vessels to the organs and the variations in
pelvic anatomy between males and females.
Similar to a right colectomy, the initial dissection
involves the development of the avascular plane between the