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_837_Библиотеки_им_академика_М_И_Перельмана.pdf
35 Chronic Constipation
273
Fig. 35.1 Algorithm for chronic constipation
Initial evaluation would include assessment for causes of secondary constipation,
including medications, metabolic disorders,
neurologic dysfunction, endocrinopathies,
and psychiatric disorders. In regards to drug
history, it is important to note the temporal
relationship between starting a particular
drug and the onset of constipation. Rectal
bleeding, abdominal pain, inability to pass
atus, vomiting, and unexplained weight loss
are warning signs and symptoms that warrant
evaluation for malignancy. After a complete
assessment of secondary causes, one can better assess for primary causes of constipation.
B. Physical
A thorough general physical exam may provide some insight into the systemic causes of
constipation. An abdominal exam can identify abdominal wall abnormalities, previous
surgical scarring, and abdominal tenderness.
274
Rectal examination is very useful in this setting since it can be used to provide information regarding distal anorectal pathologies
and assess pelvic oor function.
• The external evaluation of the anus allows
the physician to detect anal ssures, hemorrhoids, cutaneous and mucosal lesions,
and pelvic oor weakness. Evidence of
pelvic oor descent, rectal prolapse, and
anal stenosis can be seen on visual inspection. If rectal prolapse is suspected, the
patient can be asked to Valsalva while sitting on a commode.
• During the digital rectal examination, the
patient is assessed for rectal tenderness,
mucosal abnormalities, sphincter function, and gross or occult bleeding via stool
guaiac. A quick pelvic oor evaluation
can be performed by having the patient
Kegel and Valsalva with the examining
digit in the anal canal. Rectocele or vaginal prolapse can be assessed at this time as
well.
• If external visualization and digital exam are
insufcient to make a denitive diagnosis,
anoscopy can be used to visualize anal canal
to evaluate for mucosal lesions, internal
hemorrhoids, and anal ssures.
C. Diagnostic Studies
Labs
Basic bloodwork can be used to promptly
identify hematologic, endocrine, and metabolic disorders. A complete blood count can be
used to assess for anemia due to gross or occult
rectal blood loss. Thyroid function tests can be
ordered if a patient exhibits constipation with
signs of hypothyroidism. Electrolyte abnormalities associated with constipation, such as
hypokalemia and hypercalcemia, can be evaluated with serum chemistry tests. Laboratory
blood tests are important to rule out these systemic causes of constipation during the initial
evaluation of the patient.
Radiology
Radiographic tests assess the general condition of the colon in the setting of constipation by providing a baseline evaluation of the
colonic anatomy.
P. I. Denoya and S. K. Abbas
Fig. 35.2 Abdominal plain lms are usually the rst line
in imaging to detect signicant stool retention in the colon
and areas of distension such as megacolon. It can identify
fecal impaction, bowel obstruction, and fecaliths. Plain
lms can also be used to monitor bowel cleansing in
patients with fecal retention
• Abdominal plain lms are usually the rst
line in imaging to detect signicant stool
retention in the colon and areas of distension such as megacolon. It can identify
fecal impaction, bowel obstruction, and
fecaliths. Plain lms can also be used to
monitor bowel cleansing in patients with
fecal retention (Fig.35.2).
• Barium and gastrogran studies are dynamic
studies that provide information to evaluate
anatomical causes of constipation. Contrast
studies can give insight into distal colorectal
conditions that contribute to luminal narrowing. Examples include congenital conditions, such as Hirschsprung disease, as well
as obstructing colon cancer, intermittent
volvulus, and colonic strictures.
Endoscopy
Endoscopy is the best initial test for evaluation of anatomical abnormalities as a cause of
constipation. Available endoscopic modalities
to identify colonic occlusions and strictures
include rigid or exible sigmoidoscopy and
35 Chronic Constipation
275
colonoscopy. Endoscopic studies are used to
evaluate inammatory bowel disease, masses,
malignancies, strictures, diverticular disease,
and post-surgical anatomic abnormalities.
Diagnostic colonoscopies should be prioritized in patients with constipation and at high
risk of colorectal malignancies. These include
patients who are over 50years old and have
had no precious colon cancer screening,
younger patients with a positive family history
of colon cancer, and patients who present with
alarm features of malignancy.
Colon Transit Studies
Colon transit studies are most useful in
evaluating patients with infrequent defecation.
Specically, these studies are indicated for
patients with chronic constipation in order to
differentiate between slow and normal colonic
transit after they have failed conservative management with diet changes and laxatives. The
following tests measure the colonic transit
time which is dened as the time it takes for
stool to pass through the colon.
• Radiopaque marker studies measure the
colonic transit time by following the passage
of radiopaque markers as they travel through
the gut as monitored by serial abdominal
radiographs. Routinely, the patient will
swallow a capsule with 24 markers on day 1
and is followed by abdominal x-ray up to
day 5 (after 120 h). The patient should
abstain from laxatives during the duration of
the test. The test is considered abnormal if
there is retention of more than ve markers
on day 5. Based on the pattern of marker
movement within the colon, patients can
have normal colonic movement, slow transit
constipation if markers are retained in the
right or transverse colon, or outlet obstruction (dyssynergia) as markers progress normally through proximal colon and stagnate
in the sigmoid colon and rectum.
• Wireless motility capsule studies are useful
for assessing regional transit time (gastric
emptying, small bowel transit, colon transit)
and whole gut transit time. The patient swallows a capsule that is used to measure the pH
and pressures of the gut as it travels through
the digestive tract. The patient wears a wireless receiver until the capsule is expelled.
Wireless motility capsule studies are well tolerated, has good compliance, and avoids the
risks of radiation exposures. These studies
are more expensive and augment additional
ndings of motility dysfunction. Sensitivity
and specicity are similar when comparing
these two methods.
Motility Studies
Motility studies are done to evaluate defecatory disorders that involve rectal sensation
and compliance, internal and external anal
sphincter and puborectalis function, and motility patterns during defecation. They can also
be used to assess the response to biofeedback
therapy as discussed later in this chapter.
• Endorectal ultrasound is an imaging modality that allows one to assess submucosal
lesions, anatomical sphincter defects, and
the presence of stulae and deep abscesses
in the distal anorectal region. An ultrasound probe is introduced into the anal
canal, providing a circumferential image of
the rectal mucosa and perirectal tissues.
• Anorectal manometry is performed by
placing a balloon with pressure sensors in
the rectum and measuring the intrarectal
pressure and external sphincter pressure as
the patient attempts to evacuate the manometer. Normally, there is an increase in intrarectal pressure and a decrease in external
sphincter pressure during defecation. In
patients with dyssynergia, there is a paradoxical increase in external sphincter pressure during defecation. Rectal sensation
and compliance may also be assessed. The
rectoanal inhibitory reex (RAIR) should
be tested, to evaluate for possible
Hirschsprung disease. RAIR will be abnormal in Hirschsprung but also in patients
with prior coloanal anastomosis or other
surgery involving the anorectal canal.
• Balloon expulsion tests can be used as a
simple ofce screening for defecatory
dysfunction. In this test, a water lled balloon is placed in the rectum to stimulate
stool and the patient is told to expel the
276
P. I. Denoya and S. K. Abbas
balloon. The test is normal if the balloon is
expelled in less than one minute and is
abnormal if it takes more than two minutes
to expel the balloon. Balloon expulsion
tests should be used in addition to other
more rigorous tests of anorectal function.
Defecography
Defecography evaluates for anorectal
obstruction due to mechanical lesions and
physiologic muscular dysfunction. The test is
done by placing barium paste in the patient’s
rectum and instructing the patient to bear down
while sitting on a radiopaque commode.
During evacuation, the barium paste is monitored by uoroscopy. The test can be modied
to involve MRI in order to evaluate the global
pelvic oor anatomy, sphincter morphology,
and the dynamic motion during defecation.
MRI is more expensive and in most instances
is performed in the supine position, which is
not as physiologic as a sitting defecogram.
However, uoroscopic defecography is
becoming less available in many locations and
is being replaced by MRI defecography. MRI
has the added advantage of evaluating the anterior and middle pelvic compartments simultaneously with the posterior compartment, and
avoids radiation exposure.
Rectal Biopsy
Rectal biopsy is done to assess for areas of
reduced or absent ganglionic activity within
the colon. Although this test is done more
often in neonates and infants with delayed
meconium passage, it may be done for adults
with suspected undiagnosed Hirschsprung disease. In infants and young children, a suction
biopsy is performed by a device that applies a
suction cup to the wall of the colonic mucosa,
then introduces a knife to dissect a sample of
the mucosa and submucosa for histological
analysis of ganglionic cells. Alternatively, a
transanal biopsy without suction may be done
in older children and adults. The biopsy should
be done about 2 cm proximal to the dentate
line to ensure obtaining rectal mucosa and submucosa. A standard colonoscopic biopsy forceps should not be used as submucosa is
needed for the diagnosis.
Management
D. Medical Management
Initial Management
Initial treatment for constipation in adults
involves patient education regarding dietary
changes and appropriate bowel habits.
• Patients should increase their ber intake
to 20–35g per day. Potential side effects
include increased bloating, mild abdominal distension, and increased atulence.
• Patients should also increase their uid
intake to the recommended eight glasses
of water per day. Furthermore, caffeine
drinks and diuretics should be avoided
since decreased available water in the
body can contribute to the development of
constipation.
• In addition, patients are instructed to
attempt defecation during periods of
increased colonic activity, such as after
meals and in the morning.
• Patients with obstructed defecation may
benet from placing their feet on a stool or
box while defecating on the toilet to raise
the knees above the hips to simulate
squatting.
Pharmacologic Treatment
Besides lifestyle changes, pharmacologic
therapy may be used to augment initial conservative management by softening stool to
facilitate defecation.
• Bulk-forming laxatives are natural or syn-
thetic polysaccharides/cellulose derivatives
that absorb water and increase fecal mass,
increasing the frequency of defecation and
softening the consistency of stools. These
stool softeners must be used on a long-term
basis since it takes time for water to be pas-
sively absorbed into the stool. These
include agents containing psyllium or other
“ber supplements.”
• Surfactants work by lowering the surface
tension of feces, allowing water to be pas-
sively absorbed to soften the stool.
• Osmotic agents are nonabsorbable materi-
als that draws water into the colon via the
osmotic effect. This increases intestinal
35 Chronic Constipation
277
water secretion which softens stool and
increases stool frequency. This includes
agents containing polyethylene glycol.
• Stimulants act by altering electrolyte transport in the intestinal mucosa and by stimulating the intestinal motor activity,
increasing intestinal secretion and motility.
This category includes medications containing senna or bisacodyl.
• Lubiprostone is a C1C-2 intestinal epithelial chloride channel activator that increases
intestinal uid secretion.
• Linaclotide is a guanylate cyclase agonist
that increases cGMP, anion and uid secretion, and intestinal motor activity, similar
in action to stimulant laxatives.
• Misoprostol is a prostaglandin analog that
promotes intestinal motility.
The decision regarding a specic laxative
depends on patient tolerance and physician preference. Other methods of medical management
include suppositories and botulinum toxin injections. These options are usually saved until the
constipated patient fails the previously described
medical management. Glycerin or bisacodyl suppositories act by liquefying stool to bypass any
defecatory dysfunction. Botulinum toxin is used
rarely for patients with pelvic oor dysfunction
by injecting a small amount of toxin in the
puborectalis muscle, allowing the muscle to relax
and relieving the defecatory dysfunction. This
method require repeated treatments in order to
prevent recurrence of constipation.
Biofeedback Therapy
Patients with dyssynergia can be treated
with biofeedback therapy, which uses behavioral training to correct inappropriate pelvic
oor muscle and sphincter contraction.
Biofeedback therapy uses electromyography
or manometry to provide feedback on sphincter muscle function during defecation to
allow the patient to adjust pelvic oor muscle
contraction. Other techniques include the use
of an inatable balloon in order to simulate
the passage of stool. The balloon is inated
until the patient feels the urge to defecate and
the patient attempts to expel the balloon.
Biofeedback therapy helps relieve dyssynergic constipation without the use of laxatives.
E. Surgical Management
Manual and Endoscopic Disimpaction
Surgical options are available for patients
that fail conservative medical management of
constipation. These procedures are mainly for
those suffering from slow transit constipation
and rectal outlet obstruction. Patients with fecal
impaction may undergo disimpaction, which
involved manual fragmentation of stool followed by mineral oil enema for stool softening
and colonic lubrication. If the constipation continues despite disimpaction, a water- soluble
contrast enema may be indicated to assess for
obstructions and proximal impactions. Flexible
or rigid sigmoidoscopy can be used to fractionate the proximal impactions followed by either
warm water enemas or polyethylene glycol
solutions for bowel cleansing.
Surgeries for STC
There are several procedures for patients
with slow transit constipation.
• The most radical procedure is an abdominal
colectomy with ileorectal anastomosis. The
entire colon is resected at the proximal rectum with an ileorectal anastomosis. Other
options include leaving a segment of colon
proximal to the rectum such as an ileosigmoid anastomosis, to decrease risk of an
anastomotic leak and diarrhea. It is
extremely important to rule out pelvic oor
dysfunction prior to colectomy, as this may
lead to continued constipation, possibly
requiring an ileostomy.
• A segmental colectomy can be performed
for patients that have a small dysmotile
colonic segment, such as adult Hirschsprung disease.
• In patients who have slow transit constipation and are unable to tolerate a colectomy can opt to have an antegrade
colonic enema. This procedure, done
rarely in adults, creates an appendicostomy with a valve mechanism to allow
for catheterization of the appendix for
enema uid.
278
P. I. Denoya and S. K. Abbas
Surgeries for Rectal Outlet Obstruction
• Patients with rectal outlet obstruction may
suffer from rectal intussusception, rectocele, or rectal prolapse.
• Rectocele repair is indicated when the
rectocele is 3cm or more in depth, defecography demonstrates signicant barium trapping, or the patient requires
digitation for adequate evacuation.
Several options for rectocele repair
include transvaginal posterior colorrhaphy, transanal posterior repair, transperineal repair, or transabdominal repair.
• Rectopexy is indicated for patients with a
complete rectal prolapse. This procedure
involves mobilizing the rectum and securing it to the sacrum, therefore reducing the
prolapse. Additionally, a sigmoid colon
resection may be added in patients who
have underlying constipation, but is not
necessary in the nonconstipated patient.
Pexy may be done with sutures or with
mesh. In addition, there are several resection techniques for rectal prolapse that can
be offered for elderly patients that cannot
tolerate abdominal surgery.
– Mucosal proctosigmoidectomy (Delor-
me’s procedure) is specic mucosal
prolapse and small rectal prolapse, and
involves excising the mucosa of the
prolapsed rectum in order to plicate the
underlying muscle wall and reduce the
rectum back into the pelvis.
– Perineal proctosigmoidectomy (Alte-
meier procedure) is indicated for
patients with complete rectal pro-
lapse who wish to avoid abdominal
surgery. In this transanal procedure,
the prolapsed rectum is incised, the
redundant colon is resected, and then
the colon and distal rectum are
anastomosed.
– Finally, the stapled transanal rectal
resection (STARR) procedure is
offered for elderly patients with rectoceles or intussusceptions. This operation uses two circular staplers to
perform a circumferential transanal
resection of the rectum, effectively
resecting the rectal outlet obstruction.
Suggested Reading
Agachan F, Chen T, Pfeifer J, Reissman P, Wexner SD.
A constipation scoring system to simplify evaluation
and management of constipated patients. Dis Colon
Rectum. 1996;39(6):681–5.
Bharucha AE, Dorn SD, Lembo A, Pressman A.American
Gastroenterological Association medical position statement on constipation. Gastroenterology.
2013;144(1):211–7.
Corman M, Nicholls RJ.Corman’s colon and rectal sur-
gery. Lippincott Williams & Wilkins; 2012.
Denoya P, Sands DR. Anorectal physiologic evalu-
ation of constipation. Clin Colon Rectal Surg.
2008;21(2):114–21.
Hussain ZH, Everhart K, Lacy BE. Treatment of
chronic constipation: prescription medications and
surgical therapies. Gastroenterol Hepatol (N Y).
2015;11(2):104–14.
Levitt MA, Mathis KL, Pemberton JH.Surgical treatment
for constipation in children and adults. Best Pract Res
Clin Gastroenterol. 2011;25(1):167–79.
Steele SR, Hull TL, Read TE, etal. The ASCRS text-
book of colon and rectal surgery. New York:
Springer; 2016.
Part IV
Rectal
Retrorectal Tumors
EricG.Weiss andLuanneForce
36
Refer toAlgorithm inFig. 36.1
A. Presentation
Retrorectal tumors encompass a heterogeneous group of tumors located in the presacral, or retrorectal space. The boundaries of
the retrorectal space are the presacral fascia
posteriorly, the rectum anteriorly, the rectal
stalks, iliac arteries and ureters laterally,
Waldeyer’s fascia inferiorly and the peritoneal reection superiorly. Lesions may be
categorized as congenital, neurogenic, osseous, or miscellaneous. These are rare tumors,
accounting for 1/40,000 hospital admissions. Most often, a retrorectal tumor will
present as an incidental nding on imaging
for another cause approximately 50% of the
time. In patients that are symptomatic, the
symptoms are often vague. Low back pain,
leg pain or vague rectal pain may be present.
There may also be compression of the sacral
nerves that might present as incontinence, or
pain that radiates to the buttocks and/or legs.
Alternatively, these may present with signs
of acute or chronic infection, as an abscess
or stula to the perirectal or perianal space.
E. G. Weiss (*)
Cleveland Clinic Florida, Weston, FL, USA
e-mail: weisse@ccf.org
L. Force
University of Miami, Miami, FL, USA
Evaluation
B. History and Physical Examination
A detailed history and physical examination is
important when evaluating patients with retrorectal tumors. These tumors are rare, often
presenting with vague signs and symptoms, so
a high level of suspicion must be maintained.
The patient may present with a palpable rectal
mass and be completely asymptomatic. Other
signs/symptoms may include back pain, perineal pain, constipation, and vague gynecologic complaints in women. Neurologic
complaints secondary to nerve impingement
may also be present, including lower extremity pain. Infection of the lesion may present as
chronic sinuses, recurrent pilonidal infections,
drainage into the rectum or vagina. Some
female patients may present after a difcult
vaginal delivery secondary to vaginal canal
obstruction. Patients may have vague complaints for years without a diagnosis. Physical
examination should include a thorough
inspection of the perineal skin and soft tissue,
looking for any chronic sinuses or stulae. A
skin dimple may be observed posterior to the
anus. A soft, smooth extrarectal mass may be
palpated on digital rectal exam.
C. Imaging Modalities
A variety of imaging modalities may be
used to assess retrorectal tumors, including
plain radiographs, CT scanning and
© Springer Nature Switzerland AG 2020
S. R. Steele etal. (eds.), Clinical Decision Making in Colorectal Surgery,
https://doi.org/10.1007/978-3-319-65942-8_36
281
282
E. G. Weiss and L. Force
Fig. 36.1 Algorithm for retrorectal tumors
MRI.Several “hallmarks” on imaging may
suggest a certain tumor. A plain radiograph
of the pelvis may show evidence of bony
destruction, which may indicative of a
chordoma or malignant lesion. Multiple
areas of calcication could signify a teratoma. A “Scimitar” sign consists of the
sacral border appearing to be rounded without bony destruction, which is seen in sacral
meningocele. MRI has been shown in multiple series, such as Glasgow and colleagues, to be superior to CT to evaluate
retrorectal masses. MRI can delineate the
size, location of the tumor, and any invasion
into surrounding structures and provides
better contrast enhanced image. Features of
the lesion on MRI imaging may give some
clue as to the etiology and origin of the
tumor. The presence of fat within the lesion
on MRI may be indicative of a teratoma,
dermoid cyst, liposarcoma, lipoma, myelolipoma or extramedullary hematopoiesis.
Non-fatty containing solid lesions may be
categorized as cystic or solid. Solid masses
include nerve sheath tumors (e.g., schwannoma or neurobroma), myxoma, metastasis or lymphoma. If there is evidence of
sacral invasion, the lesion may be a sacrococcygeal chordoma or another osseous
tumor. Non-fat containing cystic masses can
be categorized as tailgut cysts, cystic hamartomas, rectal duplication cyst, epidermoid
cyst, anterior sacral meningocele, or extramucosal mucinous adenocarcinomas.
D. Endoscopy
Endoscopy has a limited role in evaluating
presacral tumors. Sigmoidoscopy or colonoscopy should be performed to exclude a
primary rectal neoplasm. In the absence of a
primary rectal cancer, endoscopy can be used
to visualize the rectal mucosa and determine
if the rectum is involved by the mass to aid
with preoperative planning. Even when the
mucosa is not directly involved, a smooth
bulging may be seen related to mass effect of
the tumor on the overlying rectal wall.
ab
36 Retrorectal Tumors
283
Endoanal ultrasound may be performed, but
some difculty in interpretation is often
present, as these lesions are rare and the
endosonographer may not be familiar with
the different appearances identied. Since
these tumors are rare, there is limited experience with ultrasound for evaluation, and
often better evaluated by CT or MRI.
E. Percutaneous Biopsy
There is some debate in the literature about
the importance and usefulness of preoperative biopsies of presacral masses. Many
authors claim that there is a limited role for
preoperative biopsy given the accuracy of
MRI imaging. In addition, there have been
some reports of seeding of the biopsy tract,
which may lead to increased morbidity of
subsequent procedures, as the tract or other
organs that are in the path of biopsy may
also need resection. Furthermore, biopsy of
a meningocele may lead to fatal meningitis.
Proponents for biopsy indicate that tissue
diagnosis is more accurate and concordant
with postoperative pathologic results in
comparison with MRI alone. In addition, the
presence of a malignant tumor may indicate
a need for neoadjuvant therapy prior to surgical resection. Preoperative biopsy may
guide therapeutic options for inoperable
tumors or prior to operative intervention. A
large, unresectable chordoma may benet
from high dose radiation therapy as a palliative option. Retrorectal sarcomas may also
benet from adjuvant treatment. GIST
tumors may occur in the presacral space,
which are amenable to treatment with imatinib. In general, biopsy should be individualized towards the goal of the biopsy. If
therapy in addition to surgery is initially
warranted, and pathological diagnosis is
required, then biopsy may be performed.
Moreover, if neoadjuvant therapy may allow
for tumor shrinkage (e.g., GIST), the biopsy
may be warranted. “Straightforward” lesions
that are amenable to upfront surgical resection typically do not require biopsy.
Risk Assessment
Pathology: Four Tissue Types
F. Congenital
Congenital tumors are the most common subtype of retrorectal tumors, accounting for
50–70% of all patients. Developmental cysts
are the most common congenital retrorectal
tumors (Fig. 36.2). Majority of patients are
female. These cysts may contain cells from
any developmental cell type. Developmental
cysts could be dermoid, epidermoid, tailgut or
teratomas. Epidermoid cysts contain a squa-
Fig. 36.2 (a) CT scan
image of an epidermoid
cyst. (b) Sagittal view.
(Courtesy of Dr.
Laurence Sands)