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408
G. J. Chang
Neoadjuvant Chemoradiotherapy
• Preoperative chemoradiotherapy has typically
been administered in a “long-course” fashion,
with radiotherapy and a radiosensitizing chemotherapeutic agent administered over a 5–6week period with a 6–10-week treatment
break prior to proctectomy. This extended
period of time allows for tumor regression, if
the tumor is sensitive to the therapy.
• It is now widely recognized that tumor regression in response to neoadjuvant treatment is
an important prognostic indicator of longterm outcome. It can be associated with tumor
volume reduction, downstaging, and nodal
sterilization, and a number of pathologic grading systems now exist to describe the extent of
response (Table30.1).
• Following completion of CRT, up to 50% of
patients will experience a clinical complete
response (cCR) as dened by replacement of
the tumor bed by scar or normal appearing
mucosa on clinical and endoscopic
examination.
• Pathologic complete response (pCR—specimen without evidence of residual tumor cells)
or pathologic near-complete response (specimen with only single or small groups of tumor
cells) can be observed in 10–40% of patients
following neoadjuvant chemoradiation therapy (nCRT).
• Complete clinical response, however, is not
necessarily predictive of pathologic response.
• With improved surgical techniques, distant,
rather than local, disease recurrence has
emerged as the primary cause of tumor-related
death.
The Watch andWait Approach
• In 2004 Habr-Gama and her group rst
reported outcomes for selective surgery with a
nonoperative (aka “watch and wait” or “wait
and see”) strategy in select patients who
achieved a clinical complete response following chemoradiation therapy.
• Following Habr-Gama’s original report, other
investigators initially reported a wide range of
success with an initially nonoperative
approach, including a locoregional treatment
failure rate of up to 50–60%, much higher
than the 3% failure rate initially reported by
Habr-Gama. While not fully explained, the
reasons for this discrepancy may have included
differences in initial tumor burden, selection
Table 30.1 Tumor regression grading systems
TRG Mandard (1) Dworak (2) Rödel (3) Ryan (4) CAP (5)
0 No regression No regression No residual
1 No residual
cancer cells
2 Rare residual
cancer cells
3 Fibrosis
greater than
residual
cancer
4 Residual
cancer greater
than brosis
5 No regression
Dominant tumor mass with
obvious brosis and/or
vasculopathy
Dominantly brotic changes
with few tumor cells or
groups
Very few (difcult to nd
microscopically) tumor cells
in brotic tissue with or
without mucous substance
Complete regression Complete
Fibrosis <25%
of tumor mass
Fibrosis
25–50% of
tumor mass
Fibrosis >50%
of tumor mass
regression
No residual cancer
cells or single cells
Residual cancer
outgrown by brosis
Signicant cancer
outgrown by cancer or
no brosis with
extensive residual
cancer
tumor cells
Single or
small groups
of cancer
cells
Residual
cancer
outgrown by
brosis
Minimal
evidence of
brosis
30 Rectal Cancer: Watch andWait
409
of patients for a watch and wait approach following neoadjuvant therapy, method and timing of assessment, or the neoadjuvant
treatment regimen.
• In addition, the method of selection of patients
for inclusion in the nonoperative therapy arm
in Habr-Gama’s initial report may have played
a major role. Specically, patients were not
included in the study (observation) group until
they had been followed for 12months following chemoradiotherapy. Put another way,
patients initially selected for nonoperative
therapy who then failed in the rst 12months
were excluded from analysis. This has the
potential to bias the results heavily in favor of
the observation group.
• Recent data, including from an updated report
by Habr-Gama, indicates that the true risk for
locoregional treatment failure is approximately 30%. This suggests that a number of
patients initially thought to have a pCR based
on clinical assessment of complete response
actually had undetected viable tumor, highlighting one of the major challenges and pitfalls of the watch and wait approach.
• One potential solution to the challenge of clinically identifying patients with a pCR is to
ensure a close follow-up strategy. This will
only be effective, however, if salvage treatment is proven to be effective.
• Although no specic follow-up regimen has
been compared prospectively to any other, it is
reasonable to consider frequent digital rectal and
endoluminal examination combined with carcinoembryonic antigen level determination (some
investigators recommend a 3–4-month interval)
and relatively frequent pelvic magnetic resonance imaging (MR) with rectal cancer protocol
(some investigators recommend a 3–6-month
interval) with biopsy of any suspicious lesions.
• The majority of tumor regrowth is usually
detected within the rst 12–24 months, in
which case patients may be eligible for curative resection.
• There is concern that a longer delay to surgery
will result in making the salvage resection
more difcult. Although it has been reported
that salvage surgical resection after nonopera-
tive management is feasible, longer delays in
identication of regrowth have been associated with more than a 50% decrease in the
ability to perform sphincter-preserving salvage surgery.
– Tumor regrowth occurring deep to the
mucosa may be difcult to identify before
more extensive sphincter involvement, and
the addition of radiation-induced posttreatment brosis along the pelvic oor or anal
sphincter complex may also preclude subsequent sphincter-preserving resection.
• Before a nonoperative strategy can be broadly
applied, it is important to ensure that oncologic outcomes are not being compromised,
particularly for this group of patients who are
expected to have excellent outcomes, with an
extremely low risk for either local or distant
disease recurrence, with proctectomy.
• Finally, what remains to be settled is if leaving
the rectum containing residual viable tumor in
patients with cCR but not pCR increases the
risk for distant failure.
• Despite these concerns, the evidence in support of a watch and wait approach is growing.
A limited number of prospective series have
been reported on nCRT followed by observation (Table30.2). A review of the wait and see
approach published in 2012 identied 30 publications from 9 series including 650 patients.
While demonstrating proof of principle, signicant heterogeneity of the studies in staging, inclusion criteria, study design, and
follow-up rigor limit our ability to draw rm
conclusions.
Clinical Assessment ofTreatment
Response
• The clinical assessment of treatment response
is difcult and is perhaps the greatest challenge and limiting factor for safe implementation of the watch and wait approach.
• A number of different strategies have been
considered including clinical assessment, fullthickness local excision, metabolic imaging,
and high-resolution pelvic MRI imaging.
410
Table 30.2 Comparison of selected modern studies
Series
Mass 2011 21 20 15 (observed)
Dalton
2012
Habr-Gama
2014
Smith 2015 73 72 26% 4-year OS 91% (obs)
Smith 2015 18 30 68.4 (mean) 1 patient Alive with pelvic
Number of
patients observed
12 37 25.5 (mean) 24% 50% Disease free at
93 90 60 49% 31% 5-year OS 91%
Number of
patients operated
Median follow-up
(months) cCR
100% 1 patient 2-year OS 100%
35 (operated)
Local
regrowth Outcome
2-year DFS 89%
follow-up
5-year LRFS 69%
5-year DFS 68%
vs. 95% (surg)
4-year DSS 91%
(obs) vs. 96% (surg)
disease at 54months
G. J. Chang
• The concordance between clinical and pathologic evaluation has traditionally been poor
both in terms of sensitivity (~25%) for detecting pCR and specicity (~60–90%) for
excluding residual disease.
• There has not existed a standard method for
the clinical evaluation of complete response.
Investigators have advocated for a combination of digital rectal examination and endoluminal visualization to identify residual mass,
ulceration, nodularity, or stenosis, all of which
may suggest persistent tumor. Findings in support of a complete response include regular
and smooth mucosa and changes such as whitening or presence of telangiectasias.
• Given the challenges for clinical assessment of
residual disease within the bowel wall, a number of investigators have considered local excision of the tumor bed as both a diagnostic test
to assess pathologic treatment response and a
therapeutic maneuver to excise any residual
tumor cells residing within the bowel wall.
– Endoscopic biopsy alone has the obvious
limitation of being able to provide only a
supercial sampling of the tumor bed that
can miss residual disease that may be present more deeply within the bowel wall or
away from the site of biopsy.
– Full-thickness excision of the entire tumor
bed may be performed through a variety of
approaches including transanal excision,
transanal endoscopic microsurgery (TEM),
or transanal minimally invasive surgery
(TAMIS).
• Complete pathologic assessment of the
bowel wall can be performed, and ypT
stage has prognostic implications
regarding ypN stage, but it is not a perfect correlation.
• An additional major limitation of fullthickness excision following nCRT is
that it is associated with signicant
treatment-associated toxicity including
poor healing and pain.
• Finally, the watch and wait strategy may
perhaps have the greatest appeal for
patients whose tumors involve the anal
sphincter for whom sphincter preservation would be impossible. Full-thickness
excision in this circumstance would
necessitate at least partial resection of
the internal sphincter. Thus the role for
full-thickness excision in a watch and
wait approach remains limited.
• Two primary approaches to radiologic imaging for the assessment of treatment response
have been investigated:
18
–
Fluorodeoxyglucose positron emission
computed tomography (PET-CT): Despite
its utility in signaling response to systemic
30 Rectal Cancer: Watch andWait
411
Table 30.3 MRI tumor regression grade (mrTRG)
mrTRG Description
1 Tumor bed with low signal intensity
signaling brosis with no residual
intermediate tumor signal
2 Tumor bed with predominance of brosis
with minimal residual intermediate tumor
signal
3 Substantial intermediate intensity tumor
signal present, but does not predominate
over low-intensity brosis
4 Minimal brosis
5 No change from baseline
therapy for a variety of malignant diseases,
metabolic imaging with PET has not been
shown to be reliable for the identication
of complete responders.
– MR: This is currently the most useful
imaging modality in watch and wait
strategies.
• Areas of treatment response and brosis
are characterized by low signal intensity
on T2-weighted imaging. The presence
of uniform low signal intensity with the
absence of areas of intermediate signal
intensity within it is suggestive of a pCR.
• Based on these ndings and a comparison to pretreatment MRI, a tumor
regression grade has been proposed by
the MERCURY study investigators
(Table30.3).
– The so-called mrTRG of 1–3 corre-
lated with better survival outcomes
when compared to mrTRG 4–5,
comparable to the difference in survival observed when comparing
ypT0-3a vs. ypT3b or greater.
– There is currently great interest in the
potential for the addition of diffusion
weighting or functional dynamic
contrast-enhanced MRI to improve
the detection of response, and other
technologies may still be on the
horizon.
Increasing theRate ofComplete
Response
• Based on the presumption that patients with
pCR are eligible for an organ-preserving
watch and wait approach, a number of investigators have tried to improve the rate of PCR
with neoadjuvant therapy using one or more
of the following techniques:
– Radiotherapy dose intensication includ-
ing contact radiation
– Utilization of more active chemotherapeu-
tic regimens
– Utilization of induction or consolidation
chemotherapy
– Increasing the time interval from chemora-
diotherapy to surgery
• However, it is critical to understand that
increasing the pCR rate by simply increasing
the time interval from neoadjuvant therapy to
surgery alone may have no impact on
prognosis.
– Tumor cell death is initiated immediately
(during neoadjuvant therapy), but the pCR
rate can be manipulated by changing the
duration of delay prior to proctectomy.
Therefore, one cannot assume that one
neoadjuvant therapy regimen is superior to
another based on pCR rate if proctectomy
occurs at different intervals following neoadjuvant therapy.
Proctectomy
EmmanouilP.Pappou andMartinR.Weiser
31
Key Concepts
• A proper proctectomy with sharp dissection
along the visceral and parietal layers of the
endovascular fascia facilitates margin-negative resection, reduces local recurrence, and
limits nerve injury associated with sexual
dysfunction.
• Precise understanding of pelvic anatomy
including fascial planes, autonomic nerves,
and pelvic oor musculature is critical in performing a proper proctectomy.
• The quality of mesorectal excision and the
distance of the circumferential radial margin
are associated with local pelvic control.
• Proctectomy can be performed using open,
laparoscopic, and robot-assisted techniques.
Background andGeneral Concepts
• At the beginning of the twentieth century, the
majority of patients diagnosed with rectal cancer in Europe and the United States underwent
E. P. Pappou
Department of Colorectal Surgery, Columbia
University, New York, NY, USA
M. R. Weiser (*)
Department of Surgery, Memorial Sloan Kettering
Cancer Center, New York, NY, USA
e-mail: weiser1@mskcc.org
perineal proctectomy which was highly morbid, with poor oncologic results.
• In 1908, William Ernest Miles of St. Mark’s
Hospital in London advocated the abdominal
perineal excision (APE) or, as it came to be
called, abdominoperineal resection (APR) to
more completely remove the lymphovascular
supply of the rectum.
– APR soon became the surgical procedure
of choice for treatment of carcinoma of the
rectum. Compared with perineal proctectomy, long-term outcomes following this
new operation improved considerably.
• Miles’ emphasis on the necessity of removing
the mesorectum in its entirety would become
the guiding principle of what is now known as
total mesorectal excision (TME). Today, TME
remains the gold standard in rectal cancer
surgery.
• TME entails sharp—rather than blunt—dissection of the visceral and parietal layers of
the endopelvic fascia, resulting in intact
removal of the rectum and mesorectum. In
Miles’ time, however, most surgeons continued to perform traditional blunt dissection,
limiting the benets of APR and resulting in a
25% rate of positive resection margins, with
high rates of recurrence and mortality.
• The absolute necessity of sharp dissection in
every rectal cancer operation—i.e., meticulous removal of the entire mesorectum along
the areolar plane outside of the rectal fascia
© ASCRS (American Society of Colon and Rectal Surgeons) 2019
S. R. Steele et al. (eds.), The ASCRS Manual of Colon and Rectal Surgery,
https://doi.org/10.1007/978-3-030-01165-9_31
413
414
E. P. Pappou and M. R. Weiser
propria—was reemphasized in 1982 by Bill
Heald.
• The aims of TME are to excise the rectum and
surrounding mesorectum, including its blood
vessels and pararectal lymph nodes, within an
intact visceral fascial “envelope”; to complete
en bloc resection of the lymph nodes along the
superior rectal and inferior mesenteric arteries; and to achieve clear resection margins.
• Advocates of “total mesorectal excision” have
focused attention on two critical components
of oncologic proctectomy: the lateral (radial)
margin and the distal margin of mesorectal
excision.
– Sharp dissection in the avascular plane sur-
rounding the mesorectum, so as to remove
the mesorectum in its fascial envelope and
achieve a wide circumferential radial margin (CRM), has been demonstrated to be
essential in avoiding local recurrence of
tumor in the pelvis.
– The second component of total mesorectal
excision, as advocated initially by Heald
etal., is the removal of the entire mesorectum distal to the tumor. However, the
necessity of removing mesorectum more
than 4–5 cm distal to a proximal rectal
tumor is not supported by pathologic studies of lymph node involvement in the
mesorectum.
• At present, many advocates of “total
mesorectal excision” limit mesorectal
resection to 4–5 cm distal to proximal
rectal tumors, although some authors
still refer to this technique as “total”
mesorectal excision, which has caused
confusion. Other groups have termed
the concept of tailoring the mesorectal
excision to the position of the tumor
“tumor-specic mesorectal excision,”
which may be more accurate.
• In summary, for all patients with rectal cancer,
it is critical that the primary tumor is removed
in its entirety. In addition, mesenteric tissue at
greatest risk for nodal metastases should also
be resected.
– For patients with mid and distal rectal
cancers, appropriate proctectomy tech-
nique will involve removing the entire
mesorectum.
– For patients with proximal rectal cancers, it
is important to remove the mesorectum for
a distance of approximately 4–5cm distal
to the tumor, although resecting the mesorectum distal to that point does not appear
to confer benet.
Anatomy oftheMesorectum/Rectal
Fascia
• The rectum is surrounded by a recognizable
annular envelope: the rectal fascia (or mesorectum, as it is better known to surgeons). The
mesorectum contains the lymphovascular supply of the rectum and upper anal canal. It
encloses the branches of the superior rectal
artery and the perirectal lymph nodes, which
drain in a caudal direction toward the inferior
mesenteric artery. Around the rectum is an
avascular plane, surgically recognizable as a
cobweb of areolar tissue.
• The mesorectum is asymmetrically distributed. The bulk of it sits posterior to the rectum, identied by two protruding bulges (the
“mesorectal cheeks”); anteriorly and laterally,
the perirectal tissue is thinner. Similarly, the
mesorectal fascia is most developed on the
posterior aspect. Anteriorly the mesorectum is
thinner and bordered by the recto-genital septum known as Denonvilliers’ fascia.
• In men, Denonvilliers’ fascia separates the
rectum and mesorectum from the prostate and
seminal vesicles. In women, the thinner rectovaginal fascia separates the rectum from the
vagina. Ligaments below and lateral to the
peritoneal reection connect to the parietal
fascia on the pelvic sidewall.
• The sympathetic autonomous system is
responsible for urinary continence and ejaculation, whereas the parasympathetic system
controls micturition, as well as genital erection and lubrication.
– The sympathetic autonomic plexus arises
from lumbar sympathetic nerves originating in the T12-L2 spinal junction, which
Proctectomy
415
pass anterior to the aorta and form a network in close proximity to the origin of the
inferior mesenteric artery. This is known as
the superior hypogastric plexus. The superior hypogastric plexus enters the pelvic
cavity anterior to the sacral promontory
and splits into fairly well-dened left and
right hypogastric nerves (Fig. 31.1).
Damage to this sympathetic plexus during
ligation of the inferior mesenteric artery, or
damage to the hypogastric nerve trunks
during mesorectal mobilization, can lead to
urinary incontinence and retrograde
ejaculation.
– The hypogastric nerves course posterolat-
eral to the mesorectum and ultimately join
parasympathetic nerves—also known as
the pelvic plexus, pelvic splanchnic nerves,
or nervi erigentes—to form the inferior
hypogastric plexus.
– The parasympathetic nerves that join the
sympathetic system originate from the S2–
S4 sacral spinal nerve roots, lying posterolaterally along the mesorectal fascia.
Preservation of the pelvic splanchnic
nerves and the inferior hypogastric plexus,
and careful separation of these from the
Fig. 31.1 The superior hypogastric plexus splits into the
right and left hypogastric nerves as it enters the pelvic
cavity. Parasympathetic pelvic splanchnic nerves, also
known as nervi erigentes, arise from sacral spinal nerves
S2-S4 and pierce the presacral fascia on the left and right
side to join the hypogastric nerves, forming the inferior
hypogastric plexus (not shown). (With permission from
Lee-Kong etal. Autonomic nerve preservation during rectal cancer resection. J Gastrointest Surg. 2010;14:416–22.
© Springer)
rectum, is one of the most challenging
aspects of proctectomy. The inferior hypogastric plexus forms an extensive network
of interlocking bers of the sympathetic
left and right hypogastric nerves and parasympathetic pelvic splanchnic nerves are
situated on the pelvic sidewall.
– Various nerves leave the inferior hypogas-
tric plexus to enter the rectal wall, while the
remaining neurovascular bundles extend
anterolaterally to the seminal vesicles, distal ureters, vasa deferentia, urinary bladder,
and prostate and cavernous bodies in men
and in the similar anatomic area in women,
for whom the lower portion of the inferior
hypogastric plexus runs along the lower
lateral wall of the vagina.
• Laterally the mesorectum is sometimes not
completely covered by a layer of fascia and is
penetrated by the middle rectal vessels (coming from the internal iliac vessels, present in
about 10–20% of patients) and autonomic
nerves from the inferior hypogastric plexus.
• Posterior to the mesorectum is the presacral
fascia, which follows the concavity of the
sacrum. The presacral fascia is a thickened
parietal fascia that covers the presacral veins
and fat, extending laterally to join
Denonvilliers’ fascia anteriorly. Inferiorly,
between the levels of the third and fourth
sacral vertebra, the mesorectum and the presacral fascia fuse. The thick connective tissue
bridging these two separate fascias is also
known as the rectosacral fascia or Waldeyer’s
fascia.
– Waldeyer’s fascia is an important surgical
landmark during posterior rectal mobilization, because of its close relationship to the
sympathetic hypogastric nerves and the
inferior hypogastric plexus. Inaccurate dissection at this level can lead anteriorly to
breach of the mesorectum and posteriorly
to tearing of the fascia, resulting in considerable bleeding from the presacral veins.
• At the most distal part of the rectum, the
mesorectum thins out as a recognizable
structure so that it is virtually absent over the
nal 1cm of the rectum. Distal rectal can-
416
Bladder
The holy plane
ab
E. P. Pappou and M. R. Weiser
cers are thus at greater risk of invading surrounding structures than proximal rectal
cancers, particularly the pelvic oor/external anal sphincter, vagina, or prostate,
because of the relative paucity of mesorectum at this level.
Surgical Principles ofProctectomy
forRectal Cancer
The basic principles of proctectomy are as
follows:
1. Sharp dissection circumferentially around the
mesorectum in an avascular areolar plane
between the visceral and parietal layers of the
endopelvic fascia (Figure31.2a).
2. Identication and preservation of the autonomic nerve plexus that controls bladder and
sexual function (Figure31.2b).
3. Achievement of a circumferential margin that
is macroscopically and microscopically clear
of tumor.
4. Preservation of the anal sphincter complex
and pelvic oor, with restoration of gastrointestinal continuity when appropriate.
Pathological Assessment
• Pathological analysis of the excised proctectomy specimen provides important prognostic
information on the stage and biology of the
tumor.
• In addition to assessment of proximal, distal,
and circumferential radial margins, pathologists should grade the quality of the mesorectal specimen. This has been demonstrated to
have prognostic signicance.
• Pathologic analysis is also a means of assessing the quality of surgery, because margin status and quality of mesorectal excision can be
used as surrogates for oncologic outcome
assessment.
• The College of American Pathologists (CAP)
has implemented standardized assessment of
rectal cancer specimens.
– The surgeon or pathologist should ink the
non-peritonealized radial margin of the
fresh resection specimen to help guide this
analysis.
– A standardized synoptic report should
include a subjective assessment of
mesorectal grade and quantitative measurement of CRM in millimeters.
Prostate
Tumour
TME plane
Tumour
Neurovascular
Denonvilliers
Mesorectum
Lymph node
metastases
Pelvic cancer surgery: modern breakthroughs and future
advances. NewYork: Springer; 2015. p.531. © Springer
2015). (b). The plane of total mesorectal excision allows
complete removal of regional lymph nodes while sparing
the neurovascular bundles. (With permission from Heald
RJ, etal. Embryology and anatomy of the rectum. Semin
Surg Oncol. 1998 Sep;15(2):66–71. © John Wiley and
Sons)
Fig. 31.2 Total mesorectal excision. (a) Dissection fol-
lows the dotted line. Tumor deposits are often present
within the lymphovascular tissue surrounding the rectum
(mesorectum). Incomplete resection leaves residual
deposits which are most likely the origin of local treatment failure. (With permission from Janjua AZ, Moran B,
Heald RJ. Open surgical management of rectal cancer.
Patel HRH, Mould T, Joseph JV, Delaney CP, editors.
bundle
fascia
Proctectomy
417
– A margin is considered positive if the pri-
mary tumor or involved lymph node extends
to within 1mm of the resection margin.
Preoperative Preparation
• Oral mechanical bowel preparation with oral
antibiotics
– In addition to the impact of bowel prepara-
tion on wound infection, cathartic bowel
preparation will:
• Clear the rectosigmoid of stool, in order
to accurately assess the position of the
tumor intraoperatively.
• Facilitate division of the colon and rectum.
• Clear the intervening colon free of stool,
which is important in the case of anastomotic leak following restorative.
• Preoperative broad-spectrum intravenous
antibiotics
• Thromboembolic prophylaxis with unfractionated heparin or low molecular weight heparin combined with intermittent pneumatic
compression devices
• Discussion of potential impact on fertility
with all individuals of childbearing potential
• Discussion of potential function consequences
of restorative and non-restorative proctectomy
• Preoperative stoma site marking and stoma
teaching, preferably by an enterostomal
therapist.
ence of a temporary diverting ileostomy
may increase the severity of chemotherapyinduced enteritis.
– The added risk of colorectal or coloanal
anastomotic leak may not be warranted
because if leak occurs, systemic chemotherapy may be delayed. In addition, chemotherapy must be stopped temporarily to
close the ileostomy; if complications ensue
from this second procedure, systemic chemotherapy may again be delayed. Lastly, the
functional derangements associated with
low pelvic anastomosis will only be exacerbated if the patient receives cytotoxic chemotherapy, which may produce enteritis.
• It may be preferable to simply perform a
Hartmann’s resection for mid and distal rectal
adenocarcinoma that does not invade the pelvic oor or anal sphincter, in patients with
unresectable distant metastatic disease.
• For patients with proximal rectal cancer who
may not require temporary fecal diversion and
are at low risk for anastomotic complications,
it is reasonable to perform anterior resection
with primary anastomosis, even in the setting
of unresectable distant metastatic disease (if
this was the original plan).
• If the primary tumor is felt to be unresectable,
then fecal diversion alone should be considered. Except in rare circumstances, there is
little value in debulking rectal cancer.
Operative Approaches
Abdominal Exploration
andDecision-Making
• The abdominal cavity is explored thoroughly,
especially the liver and the peritoneum, to identify signs of distant metastatic disease. If unresectable distant metastatic disease is encountered,
then the surgeon should carefully consider
whether low pelvic anastomosis is warranted.
– Patients with unresectable distant meta-
static spread often undergo prolonged
treatment with chemotherapy; and the pres-
Open Low Anterior Resection (LAR)
• The patient is placed in a modied lithotomy
or supine split-leg position.
• A variety of incisions can be utilized; however, it is important to keep the incision line
away from the area of potential stoma and
stoma appliance, so as to not interfere with
management of the stoma postoperatively.
• Our preferences regarding the technical
aspects of restorative proctectomy are
described as follows:
– The small bowel is carefully packed and
retracted to the right, providing access to
the pelvis.
418
ab
E. P. Pappou and M. R. Weiser
– The sigmoid and descending colon are
mobilized to the midline.
– The space deep to the superior rectal (hem-
orrhoidal) vessels is mobilized taking care
to avoid damage to the sympathetic plexus/
hypogastric nerves.
– The superior rectal artery (just distal to the
left colic artery) or inferior mesenteric
artery, at its origin 1–2cm from the aorta,
is ligated and divided to preserve the sympathetic plexus. High ligation of the IMA
may be useful when bulky adenopathy is
present at the base of the vessel or when a
coloanal anastomosis is necessary and
maximal length of the left colon is required.
• When the inferior mesenteric artery is
ligated, care must be taken to preserve
the marginal artery, which provides the
blood supply from the middle colic
vessels to the left colon and
anastomosis.
– The inferior mesenteric vein is ligated at
the paraduodenal (ligament of Treitz) location just inferior to the pancreas and again
adjacent to the ligation site of the inferior
mesenteric artery.
• Dividing the vein at the ligament of
Treitz is critical in order to accommodate full mobilization of the splenic
exure, which is then allowed to rotate
into the pelvis for maximal length.
– Splenic exure mobilization is performed.
Colonic attachments to the pancreas are
then taken down, and care is taken to avoid
aggressive retraction on the colon, which
can tear the splenic capsule. Omental
attachments are then taken down from the
distal transverse colon to complete the
mobilization.
• The distal descending/proximal sigmoid mesentery is divided to the bowel wall.
• The colon is divided with a purse-string instrument and staple anvil inserted (for restorative
proctectomy with stapled anastomosis) or linear cutting stapler (for APR or coloanal
anastomosis).
• The left colon is packed superiorly, facilitating visualization of the pelvis.
• The distal segment is retracted anteriorly,
which opens the perimesorectal planes. A
sharp dissection is carried out under direct
vision, circumferentially around the
mesorectum.
• The presence of the superior hypogastric
plexus posteriorly must be kept in mind
throughout the dissection (Figure 31.3a).
Starting the dissection in the posterior and
then the lateral plane, in a stepwise manner,
Fig. 31.3 (a) The distal sigmoid/proximal rectum is
elevated anteriorly, exposing the aortic bifurcation and
sacral promontory, with identication of the left ureter,
left iliac vein, and superior hypogastric plexus. The
hypogastric nerves may appear as an obvious discrete
band of tissue or as multiple smaller bands. (b) Careful
dissection of the sigmoid mesentery distally results in an
avascular, areolar plane separating the mesorectal fascia
propria from the presacral fascia. (With permission from
Lee-Kong et al. Autonomic nerve preservation during
rectal cancer resection. J Gastrointest Surg. 2010;14:416–
22. © Springer)