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COLON
241
a
bscess). e Hinchey classication system helps surgeons identify
patients who may benet from medical management versus those
requiring resection. Hinchey stage I-II includes patients who present
with either an associated abdominal (I) or pelvic (II) abscess, whereas
Hinchey stage III-IV represents a diuse purulent (III) or fecal (IV)
peritonitis.
Patients presenting with an episode of diverticulitis complicated
by an abscess usually respond to medical management that includes
intravenous uid hydration and broad-spectrum antibiotics. Computed tomography (CT) performed with use of oral and intravenous
contrast material is the diagnostic tool of choice to evaluate the severity of the disease and to help determine the need and feasibility of
placing a drain. Most patients (>80%) will respond to antibiotic treatment; however, persistent fever, abdominal pain, and leukocytosis
aer treatment with intravenous antibiotics for 48 to 72 hours should
prompt reevaluation and a decision about whether percutaneous
drainage is indicated. Findings upon admission that are suggestive
of a high failure rate without a drain are fever higher than 101.2
the presence of a pelvic abscess (in contrast with an abdominal or
“intra” mesocolonic abscess), or an abscess larger than 4 cm. Overall,
75% to 95% of these patients will respond to medical treatment and
avoid emergency surgery. In a retrospective analysis of 136 patients
who presented with perforated diverticulitis, ve patients had free
air and nonloculated free uid at presentation and underwent surgical exploration upon admission. Of the remaining 129 patients, 109
had an abscess and limited areas of free air on an initial CT scan.
Only 28% of these patients required percutaneous drain placement.
Combined medical and percutaneous drainage was successful in 95%
of the cases, with failure occurring in only seven patients (5%) who
required a semi-elective operation. Patients who recover from an episode of complicated diverticulitis may become candidates for an elective laparoscopic sigmoid resection, although most surgeons would
not operate on a patient who had one simple abscess that resolved
eas i l y.
Acute Div
erticulitis Complicated by Purulent
°
F,
or Feculent Peritonitis: Surgical Options in the
Emergency Setting
cute diverticulitis presenting with free intra-abdominal perforation
A
carries signicant morbidity and mortality. Patients presenting with
signs of peritonitis or a rigid abdomen and intra-abdominal free air
visible on plain radiographs require emergency surgery. In patients
where physical examination ndings and initial imaging studies are
inconclusive, a CT scan is indicated. Findings of free air and diffuse, nonloculated uid suggest diuse purulent or fecal peritonitis,
which is an indication for surgical exploration. Depending on patient
comorbidities and time from onset of symptoms to presentation at
the emergency department, signs of sepsis or even of septic shock
may already be present. Intravenous broad-spectrum antibiotics and
aggressive uid resuscitation should be started promptly.
Open diversion without removal of the source (a classic threestage operation) is no longer recommended because it has a much
higher rate of morbidity and mortality than other procedures. An
exploratory laparotomy with planned resection is standard procedure in most of these cases. A nonresective exploratory laparoscopy
and peritoneal lavage (LPL) has been described as an alternative,
although this approach is supported mainly by results from small
series. Several prospective trials are currently underway in Europe.
Investigators performing a prospective randomized trial in which
patients were enrolled in either an LPL arm versus an HP or PRA
arm recently closed the LPL arm because of safety concerns; although
the data leading to this decision are not yet available, LPL cannot be
recommended as a valid surgical alternative at this time.
us a laparoscopic/open HP or a PRA, oen with a protective
loop ileostomy, are the two operations a surgeon should consider
in the setting of purulent peritonitis and in selected patients with
feculent peritonitis. When treating patients who are immunocompromised, malnourished, and/or taking steroids or vasopressors (the
use of these medications at the time of surgery should raise concern
for organ failure and septic shock), and in most cases of a diuse
feculent peritonitis, an HP is the better option. Such patients have
a poor response with any further complications, especially an anastomotic dehiscence, even with a protective loop ileostomy in place.
is is also true when treating patients with chronic life-threatening conditions such as severe congestive heart failure. However, for
some patients, a “temporary” Hartmann colostomy will end up being
permanent.
As long as patients are hemodynamically stable, we favor a laparoscopic approach because it transforms recovery and minimizes issues
with wound management. If a stoma is required, the specimen oen
can be removed through the ostomy site. Obviously this approach
depends on the experience of the surgical team. e literature favors a
laparoscopic approach whenever patient characteristics and surgical
expertise are suitable.
A nal and important factor in whether patients have an anastomosis or temporary ostomy is the quality of the distal rectum. Some
patients, even with a Hinchey stage II history, have so much rectal
inammation that the rectum is not suitable for anastomosis, or a
much lower transection is required. We do not favor such a low transection in an emergency setting because of its eect on the patient’s
bowel function.
tmann Procedure and Reversal
Har
W
hen an ostomy is being considered in patients undergoing semielective or emergent operations, the ostomy site should be marked
preoperatively.
Division of the rectum just distal to the rectosigmoid junction is
ideal, avoiding any presacral mobilization. is approach prevents a
more dicult second operation. In these cases we deliberately try not
to divide the inferior mesenteric artery because the distal rectum then
retracts low in the pelvis, particularly with laparoscopic approaches.
Although the lack of adhesions aer laparoscopic surgery usually
means the distal rectum is easy to nd at a second procedure, if the
rst operation is performed open, placement of nylon sutures makes
nding the rectal stump easier.
Proximally, the colon is divided in an area where the colonic wall
is not thickened and hypertrophied, and ideally in a section where no
diverticulae are present. It is important to ensure that the colon has
been mobilized enough so that it will reach through the abdominal
wall without tension. e splenic exure is almost never mobilized at
this operation and is le as a fresh plane for the second surgery. Using
the ostomy site as the extraction site and dividing the colon extracorporeally is our preference, unless the phlegmon is extremely large.
Another option for much larger specimens is to divide the colon
proximally using endostaplers. e specimen can be then extracted
through a Pfannenstiel incision while the proximal end is brought
up through the ostomy site and matured at the end of the procedure,
o
nce all wounds are closed.
If the initial resection is performed open and the patient is obese,
it may be dicult to make the end colostomy reach the abdominal
wall. In this case, the end of the colon can be stapled across and a
loop transverse colostomy can be constructed, which avoids the need
to mobilize the splenic exure. Under these circumstances the closure should be performed within 6 months or the diverted segment of
colon may atrophy and make colostomy takedown dicult.
Reversal of the end colostomy is also performed laparoscopically, even when the initial procedure required open surgery. e
procedure starts with end colostomy mobilization and insertion of
an anvil into the proximal healthy bowel. is is returned to the
abdomen, and a port is inserted to insuate the abdomen. e
remaining ports are inserted. e proximal colon is mobilized
adequately, and the distal rectum is dened. If the distal rectum is
242
Surgic
al Trea
TmenT of DiverTiculiTiS anD iTS complicaTionS
ealthy enough, a direct anastomosis is performed. If it is thickened
h
or in any way abnormal, it is resected and a primary anastomosis is
performed. e resected stump is removed through the ostomy site
at completion of the case.
COMPLIC
ATED DIVERTICULITIS WITH
FISTULA FORMATION
lthough fistulas are almost always managed electively, they add
A
a level of complexity to surgical management. Colovesical (65%),
colovaginal (25%), and colocutaneous are the most common
types. Coloenteric, colouterine, and some other forms of fistulas
have been described but are fairly rare and tend to follow similar
management principles. As with any patient with suspected diverticulitis, preoperative evaluation of the colon is necessary to rule
out other possible causes such as inflammatory bowel disease and
cancer.
vesical Fistulas: Diagnosis and Management
Colo
P
atients with diverticular disease complicated by a colovesical stula usually present with a history of pneumaturia and even fecaluria, with or without (recurrent) urinary tract infections. A history
of previous episodes of diverticulitis is common. Clinical manifestations vary from patient to patient, and urosepsis could be the
presenting symptom in elderly or debilitated patients. Appropriate rehydration, drainage of the bladder with a Foley catheter, and
broad-spectrum antibiotics may convert an emergency into an elec-
ive situation, allowing for correction of nutritional and electrolyte/
t
m
etabolic abnormalities (i.e., renal dysfunction) prior to surgery.
Urinalysis is usually abnormal, and a CT scan may show air in the
bladder with no history of bladder instrumentation. Cystoscopy is
usually not necessary, except when malignant invasion of the bladder is suspected.
When treating colovesical stulas, the bladder defect is usually not
identiable, and if it is, it doesn’t require repair. It is usually located
near the dome of the bladder. e bladder is routinely lled in a retrograde fashion through the Foley catheter to assess for the presence
of a defect that might require repair. If none is found, the Foley catheter is kept in place for 48 hours and a cystogram is obtained prior
to removal and subsequent hospital discharge. In cases in which a
leak is seen, the edges are debrided laparoscopically, and laparoscopic
placement of reabsorbable sutures is performed. In these cases, the
Foley catheter is maintained in place aer surgery for 2 weeks before
obtaining a cystogram. Interposing omentum between the bladder
and the colorectal anastomosis may decrease the chance of a stula
recurring in the setting of an anastomotic leak.
vaginal Fistulas: Diagnosis and Management
Colo
olovaginal stulas may develop in women who have a history of
C
recurrent episodes of diverticulitis. ese patients have almost always
undergone a hysterectomy. In many cases, the stula opening is very
small and dicult to identify. Patients may report passing gas and
even stool through the vagina. Complaints of brown malodorous discharge and recurrent urinary tract infections are common. Vaginal
examination may show some brown discharge, granulation tissue, or
umbilication of the vaginal wall. Numerous diagnostic studies such
as a CT scan, contrast enema, exible sigmoidoscopy, and vaginoscopy have been used to ensure a correct diagnosis prior to surgery,
although we oen conrm the diagnosis at surgery without multiple
additional tests. A thorough anorectal examination rules out an anovaginal stula. Because of the more indolent and chronic nature of
this problem, patients may present with signicant weight loss and
various degrees of malnutrition, and improving the patient’s overall
tatus prior to surgery may help avoid the need to construct a protec-
s
tive loop ileostomy.
In the management of a colovaginal stula, placing a healthy wellvascularized tissue, such as the omentum, between these two organs
once the stula has been taken down may help decrease the chance
of stula reformation. Laparoscopic creation of an omental ap to
interpose between the vagina and the newly constructed colorectal
anastomosis is technically easy. e omentum is divided very close
to the stomach wall, preserving the gastroepiploic pedicle. Vessels
from the greater curvature of the stomach to this pedicle can be safely
divided with the use of advanced bipolar devices. e vaginal defect
itself is sutured with absorbable sutures if feasible.
Colocutaneous Fistulas:
Colocutaneous stulas are uncommon and generally occur in
patients with previous placement of a percutaneous drain for an
abscess during a previous episode of acute diverticulitis. In the
absence of a persistent infectious process or distal colonic obstruction, these stulas may close over time. When they persist, treatment
follows the same principles that are discussed in the following sections. In these cases, however, adequate drainage of the stula tract
and healing by secondary intention is important to prevent abdominal wall complications.
CUTE COLONIC OBSTRUCTION:
A
Diagnosis and Management
PATIENT SELECTION FOR EMERGENT
VERSUS SEMI-ELECTIVE OPERATIONS
R
ecurrent episodes of diverticulitis can lead to chronic obstruction of
the sigmoid colon, with patients requiring a semi-elective operation.
A superimposed inammatory/infectious process may cause these
patients to present with symptoms of acute large bowel obstruction
that may require emergency surgical treatment. In cases in which the
ileocecal valve is incompetent and the small bowel is dilated, initial
treatment with intravenous uids, nasogastric tube decompression,
and intravenous antibiotics may allow the acute inammatory process to resolve. is initial treatment allows time to correct electrolyte
abnormalities and improve renal function. Oen these patients have
been vomiting and are dehydrated when they present to the emergency department. A competent ileocecal valve, on the other hand,
creates a closed-loop obstruction that could lead to necrosis and
perforation of the cecum, as dilation progresses and cecal diameter
reaches 12 cm or more. Changes in operative planning and decision
making are usually required. In cases in which patchy necrosis or
serosal tears at the level of the cecum are present, the surgeon is faced
with the need to perform a total colectomy with either an end ileostomy or an ileorectal anastomosis with or without a diverting loop
ileostomy. A controversial option that may function as a bridge to a
more elective surgery is placing a stent through the stenotic segment.
e length of the stenosed segment in diverticular disease is usually
longer than that caused by cancer and may be very technically challenging to stent. However, as expertise with stents increases, placing
a stent through the stenotic segment could represent an alternative
approach in these cases. Relieving the closed-loop obstruction may
allow time to correct metabolic abnormalities and improve overall patient status. As the colon recovers tone and caliber, the risk of
perforation when manipulated during surgery, especially if a minimally invasive approach is planned, may decrease. Although it is
not mandatory, patients may be able to tolerate a bowel preparation
and undergo a more selective laparoscopic resection. Nevertheless,
performing a segmental resection and anastomosis without prior
mechanical preparation has been demonstrated to be safe in numerous publications, and it does not mandate a protective loop ileostomy.
On-table colonic lavage is currently not a mandatory step prior to
construction of an anastomosis in the management of obstructive
sease. ese points are discussed in more detail in the chapter on
di
large bowel obstruction.
RECURRENT DIVER
TICULITIS IN
PATIENTS WHO HAVE PREVIOUSLY
UNDERGONE RESECTION FOR
DIVERTICULAR DISEASE
R
ecurrent diverticulitis is rare aer adequate resection. In many
cases, the reason for these new episodes of diverticulitis can be traced
to the initial operation. Although removal of all the diverticuli is not
necessary, failure to perform a complete sigmoid resection increases
the risk of the development of recurrent diverticulitis from 4% to
16% as a result of leaving the high pressure zone of the rectosigmoid.
It is critical that distal bowel division take place in the upper rectum, just distal to the rectosigmoid junction. Patients with recurrent
diverticulitis should have a colonoscopy to exclude Crohn disease or
a newly diagnosed colon cancer. Irritable bowel syndrome also can
mimic diverticulitis, and ascertaining a correct diagnosis can be difcult, especially when investigative studies such as a contrast CT or
a barium enema show diverticulosis and a poorly distensible colon
near the anastomotic site. Whenever an elective repeat operation is
recommended, it is important to manage patient expectations preoperatively. When irritable bowel syndrome is present, some of the
symptoms may not improve aer resection. Having this conversation
“aer the fact” may lead to a breakdown of the patient-surgeon relationship; it is therefore recommended that prior to a repeat operation,
alternative treatments such as probiotics, nonabsorbable antibiotics,
and 5-aminosalicylic acid compounds be discussed.
COLON
S
u
g g e
iondo S, Lopez Borao J, Millan M, et al. Current status of the treat-
B
ment of acute colonic diverticulitis: a systematic review. Colorectal Dis.
Delaney CP, Brady K, Woconish D, et al. Towards optimizing periopera-
tive colorectal care: outcomes for 1,000 consecutive laparoscopic colon
procedures using enhanced recovery pathways. Am J Surg. 2012;203(3):
353–355.
Dharmarajan S, Hunt SR, Birnbaum EH, et al. e ecacy of nonopera-
tive management of acute complicated diverticulitis. Dis Colon Rectum.
2011;54(6):663–671.
Feingold D, Steele SR, Lee S, etal. Practice parameters for the treatment of
sigmoid diverticulitis. Dis Colon Rectum. 2014;57(3):284–294.
Klarenbeek BR, Veenhof AA, de Lange ES, etal. e Sigma-trial protocol: a
prospective double-blind multi-centre comparison of laparoscopic versus
open elective sigmoid resection in patients with symptomatic diverticulitis. BMC Surg. 2007;7:16.
Regenbogen SE, Hardiman KM, Hendren S, Morris AM. Surgery for diver-
ticulitis in the 21st century: a systematic review. JAMA Surg. 2014.
Senagore AJ, Duepree HJ, Delaney CP, Brady KM, Fazio VW. Results
of a standardized technique and postoperative care plan for laparoscopic sigmoid colectomy: a 30-month experience. Dis Colon Rectum.
2003;46(4):503–509.
Stulberg JJ, Champagne BJ, Fan Z, et al. Emergency laparoscopic colectomy: does
it measure up to open? Am J Surg. 2009;197:296–301.
Swank HA, etal. e Ladies trial: laparoscopic peritoneal lavage or resection
for purulent peritonitis and Hartmann’s procedure or resection with primary anastomosis for purulent or faecal peritonitis in perforated diverticulitis (NTR2037). BMC Surg. 2010;10:29.
Turley RS, Barbas AS, Lidsky ME, Mantyh CR, Migaly J, Scarborough JE.
Laparoscopic versus open Hartmann procedure for the emergency treatment of diverticulitis: a propensity-matched analysis. Dis Colon Rectum.
2013;56(1):72–82.
S t
e d
R
e
a d i n g
243
L
G
H
Car
oline C. Jadlowiec and Jeffrey L. Cohen
INTRODUCTION
L
ower gastrointestinal hemorrhage refers to blood loss originating
distal to the ligament of Treitz that is symptomatic and necessitates hospital admission. It is a serious and potentially life-threatening situation. Although rectal hemorrhage can be seen in any
age group, most patients requiring admission to the hospital are
elderly and have coexistent medical problems. Because of these
comorbidities, management is complex. Many patients stop bleeding spontaneously, but up to 30% experience bleeding again during
or after their hospitalization. In the adult population, diverticulosis and vascular ectasias cause more than 90% of cases of lower gastrointestinal hemorrhage. Other less common causes are listed in
Box 50-1. Although the focus of this chapter will be on general
evaluation and management of lower gastrointestinal hemorrhage, it is worthwhile to briefly examine and contrast the two
most common causes.
ETIOLOGY
In Western society, up to 65% of the population will have diverticulosis by age 85 years. Twenty percent of patients with diverticulosis coli
will present with bleeding during their lifetime, and 5% will experience a severe hemorrhage. Although almost all of these patients stop
bleeding spontaneously, bleeding will recur in 25%. Most diverticula
are located in the sigmoid and descending colon, likely as a result
of the sigmoid colon’s high intraluminal pressure. Despite this lesided predilection, diverticular bleeding is distributed fairly equally
between the right and le sides of the colon. e pathogenesis is
believed to be injury to the submucosal arterial branches of the vasa
recta that become stretched over the diverticulum and are then subject to trauma by the passage of stool. It has been speculated that the
wider necks of the right-sided diverticula permit a greater length of
the artery to be exposed to injury, thus increasing the percentage of
bleeding from proximal diverticulosis. Diverticulitis is not usually
associated with bleeding vasa recta.
Vascular ectasias of the colon are also believed to be acquired
lesions because they are rarely observed in patients younger than 40
years. Also known as angiodysplasia or arteriovenous malformations,
these lesions are predominantly located on the right side of the colon.
It is likely that the increased wall tension of the cecum accounts for
the presence of these lesions. As described by Boley, repeated lowgrade obstruction of the submucosal veins over many years leads to
the characteristic tortuous, dilated, thin-walled vessels, which can be
identied both grossly and histologically. Arteriovenous connections
occur relatively late in this process and result from increased pressure, leading to disruption of the precapillary sphincters. A high incidence of cardiac disease, especially aortic stenosis, has been observed
in patients with vascular ectasias, and as many as 25% of patients who
present with bleeding arteriovenous malformations are noted to have
244
aortic stenosis. First described in 1958, Heyde syndrome describes a
triad of aortic stenosis, an acquired coagulopathy, and anemia occurring as a result of intestinal angiodysplasia. Although bleeding has
been reported to cease with aortic valve replacement, gastrointestinal
hemorrhage is not an indication for open heart surgery. Rather, the
decision to perform aortic valve replacement should be made on the
basis of traditional indications, with surgery for lower gastrointestinal bleeding proceeding rst if critical aortic stenosis is not present.
Bleeding from vascular ectasias tends to be venous and, therefore, is
not usually as brisk as that seen with diverticulosis. In more than 90%
of patients, bleeding will stop spontaneously, but repeated episodes
of bleeding are common, with an incidence that approached 85% in
one study.
INITIAL
EVALUATION AND
RESUSCITATION
Because many patients who present with lower gastrointestinal hemorrhage lose a large amount of blood, resuscitation must accompany
the initial evaluation. Despite the varied causes for lower gastrointestinal hemorrhage, the initial approach is standard.
In trying to quantify the degree and characteristics of a patient’s
bleeding, it is important to realize that even small amounts of blood
in the toilet can appear massive to the patient. Because blood is
a cathartic, more importance can be attached to the frequency of
bloody bowel movements prior to presentation than in trying to
quantify the exact amount of blood loss. Signicant lower gastrointestinal bleeding oen causes hemodynamic instability, and it is
essential to treat this condition while evaluating underlying causes.
A lack of hemodynamic instability does not necessarily imply a
minor bleed, however. A study from our institution revealed that,
at presentation, 90% of patients with positive ndings of an arteriogram were normotensive or hypotensive, and only 30% were
tachycardic.
As the initial evaluation progresses, the basics of cardiopulmonary resuscitation must be followed. Large-bore intravenous catheters should be placed with infusion of a balanced salt solution. Blood
samples are drawn for laboratory studies, including hemoglobin,
hematocrit, coagulation studies, blood typing, and crossmatching.
Attempts should be made to keep the patient normothermic. Placement of a Foley catheter permits accurate assessment of urinary
output and assists in uid replacement. Patients with massive hemorrhage, severe cardiac disease, or multiple comorbidities require intensive monitoring, which may include systemic arterial, pulmonary
arterial, electrocardiographic, and oximetric monitors.
Early in the evaluation, a nasogastric tube should be placed. In
many studies of lower gastrointestinal bleeding, as many as 10% of
patients initially believed to be bleeding from a colonic source were
ultimately determined to be bleeding from an upper gastrointestinal
lesion. If clear bile is not returned upon nasogastric aspiration, an
COLON
245
X 50-1:
BO
verticular disease
Di
Vascular ectasias
Colonic neoplasms
Ischemic colitis
Radiation colitis
Infectious colitis
Inammatory bowel disease
Trauma
Hematologic disorders
Rectal varices
Hemorrhoids
Anal disease
Endometriosis
Solitary rectal ulcer
Postpolypectomy bleeding
u
pper endoscopy should be performed as part of the evaluation. Even
if clear bile is noted upon lavage, upper gastrointestinal bleeding can
be seen in up to 16% of patients. e nasogastric tube can be le in
place to use as access for a rapid mechanical bowel preparation to
expedite a colonoscopy.
While resuscitation is proceeding, important information should
be obtained from the patient’s history in relation to the risk for continued or recurrent bleeding. Asking about alcohol or aspirin ingestion, a prior history of gastrointestinal bleeding, the presence of any
bleeding diathesis, coagulopathy from anticoagulation therapy, and
comorbid diseases is extremely important.
Upon physical examination, particular attention should be
directed to identifying stigmata of advanced liver disease. In addition, the presence of an abdominal mass may indicate an unsuspected
colon carcinoma. Although diverticulitis is not commonly seen with
bleeding diverticulosis, a nding of abdominal tenderness may suggest that possibility. More likely, however, would be a diagnosis of
ischemic colitis or inammatory bowel disease when a patient presents with abdominal pain, tenderness, and lower gastrointestinal
hemorrhage.
Finally, rigid sigmoidoscopy is essential early in the evaluation
of patients with lower gastrointestinal bleeding. It is generally performed in the emergency department to rule out an anorectal source
of bleeding. Hemorrhoids associated with portal hypertension can
bleed massively, and other low rectal or anal sources of bleeding may
be treatable in the acute setting. Additionally, observation of the rectal mucosa may suggest a possible source of bleeding, such as infectious, inammatory, or ischemic proctocolitis.
DIA
e diagnostic phase of lower gastrointestinal bleeding usually pro-
ceeds once the patient has been stabilized. However, because of the
dynamic nature of colonic hemorrhage, diagnostic testing occasionally must be initiated while the patient is still being stabilized. In fact,
aggressive diagnostic maneuvers can have the benet of localizing
bleeding before it has stopped. Identifying the source of bleeding
matters, especially for the 25% to 30% of patients who will experience
signicant recurrent bleeding. Early aggressive diagnostic procedures
may achieve this goal and permit nonoperative therapeutic maneuvers as well.
e most commonly used diagnostic studies performed for lower
gastrointestinal bleeding are radionuclide scanning, multidetector
computed tomography (CT angiography), angiography, and colonoscopy. In many patients, a combination of these tests will be needed,
and occasionally, because of recurrent bleeding, it will be necessary to
repeat them. Both angiography and colonoscopy can be of potential
Cause of Colonic Hemor
GNOSTIC TESTING
rhage
therapeutic benet, and this advantage adds to their usefulness as
diagnostic modalities.
Scintigra
T
wo types of radionuclide scans are available to image gastrointestinal bleeding. Initially, sulfur colloid was used as an intravascular
marker that could not return to the vascular compartment once
bleeding into the intestine had taken place. However, its rapid clearance by the reticuloendothelial system results in two distinct disadvantages. First, the patient must be actively bleeding at the time of
the injection because more than 90% of the trace is cleared within
7 minutes. Second, accumulation of activity by the liver and spleen
obscures evidence of bleeding from the colonic exures.
A second technique, injection of technetium-labeled red blood
cells, has supplanted sulfur colloid scanning as the nuclear medicine
technique of choice. It is equally safe and eective, and its only disadvantage is the 30 to 40 minutes required to label the red blood cells.
Technetium-labeled red blood cell scans are reported to be sensitive
to bleeding rates as low as 0.05 to 0.1 mL per minute. e tagged red
blood cells have an extended half-life, and scanning can take place for
24 hours aer injection.
Although tagged red blood cell scanning has gained wide acceptance as a modality to detect gastrointestinal bleeding, it is arguable
whether scintigraphy can localize a bleeding site reliably. In a review
of 72 technetium-labeled red blood cell scans performed at our institution, 71% of the positive scans accurately localized the site of bleeding as conrmed by surgery, angiography, or endoscopy. is nding
is supported by other studies in the literature, which average a false
localization rate of 25%. Recently, it has been reported that the accuracy of scanning can be enhanced by performing dynamic scintigraphy, with stratication of results based on early radionuclide blushing.
Ideally, scintigraphy should be performed while the patient has active
bleeding, yet despite a national trend toward increased 24-hour hospital sta coverage, accommodating on-request scintigraphy continues to be problematic in many hospitals. Even in large centers that
employ on-call nuclear medicine technologists, it is dicult to perform scintigraphy in a timely manner during nights and weekends.
is suboptimal usage of scintigraphy has resulted in an increased
number of false-negative studies. Additionally, despite the theoretical benet of prolonged bleeding observation (repeat scintigraphy),
it has been suggested that scans that are positive within several hours
of injection produce more accurate localization, whereas, because of
the rapid antegrade and retrograde movement of extravasated blood,
the accuracy of delayed-positive scans decreases substantially. Given
these factors, the relatively high false localization rate for scintigraphy
is not surprising. erefore, basing a bowel resection on the results of
red blood cell scintigraphy alone should be discouraged, and conrmation should be obtained prior to surgery if possible.
Radionuclide scanning has also been suggested as a cost-eective
screening tool prior to angiography. Given its increased sensitivity,
relative safety, and decreased cost compared with angiography, scintigraphy should be an ideal test to perform to increase the yield of
positive angiograms. Unfortunately, it has been dicult to support
this supposition in practice, possibly because the delay in obtaining
an angiogram while performing scintigraphy allows the “window of
opportunity” to nd a bleeding vessel to pass. A review of our experience with angiography showed that a prior positive nuclear scan did
not increase the percentage of positive angiograms compared with
use of angiography as the initial diagnostic procedure, although successful anatomic localization did permit diminished contrast mate
rial administration during angiography.
In conclusion, the exact role of radionuclide scanning remains
unclear. e examinations are minimally invasive and inexpensive,
have low complication rates, and may alert physicians to patients
who are likely to require surgery. However, at this point, it is not
safe to limit a workup and plan treatment based on the results of a
phy
-
246
Lo
wer Gastrointestina
L HemorrHaGe
radio
nuclide scan alone. Furthermore, its value as a screening test
for the cost-eective use of angiography remains questionable, and
many institutions are now using alternative modalities as rst-line
diagnostic tools.
Multidetector
n recent years, contrast-enhanced multidetector computed tomog-
I
raphy (MDCT) increasingly has been described as being useful in the
diagnosis of active lower gastrointestinal bleeds. Studies have found
that MDCT is capable of detecting colonic bleeding at rates between
0.3 and 0.4 mL per minute. is nding is signicant because the rate
of bleeding detected is lower than the 0.5 mL per minute detected
by mesenteric angiography and approaches bleeding rates detected
by radionuclide scanning. Additional benets include the 24-hour
availability of MDCT at most hospitals, as well as decreased artifact
from bowel gas and peristalsis that can result in false-positive results,
specically during mesenteric angiography. A review of the literature
shows that MDCT has a greater than 85% sensitivity and 95% specicity, with 95% overall accuracy for localizing gastrointestinal bleeding. Increased accessibility to MDCT results in a greater likelihood
that the study will be performed while the patient has active bleeding,
and it theoretically increases the likelihood of having a positive localizing study. Aer a positive MDCT study, patients should undergo
mesenteric angiography and embolization. Concerns of precipitating
renal insuciency as a result of use of this algorithm have been raised
because patients receive duplicate intravenous contrast dye loads. In
our experience, however, these concerns have not been substantiated.
Similar to scintigraphy, we have found that positive localization on
MDCT allows for decreased dye administration with the ability to
target mesenteric angiography to a specic vascular territory.
Angiogra
S
elective mesenteric angiography has become widely used for lower
gastrointestinal hemorrhage because it has the benet not only of
being diagnostic but also frequently therapeutic. By localizing bleeding to a specic vessel, angiography tremendously facilitates surgery. Furthermore, transcatheter therapy, either pharmacologic or
by embolization, can successfully treat the source of bleeding, thus
avoiding surgery.
Minimal preparation is necessary for angiography, but because
it must be assumed that the patient is actively bleeding, continuous
monitoring is necessary. Resuscitation should be continued while a
Foley catheter prevents the bladder from lling with contrast material. Selective injection is performed rst through the superior mesenteric artery, because bleeding is most likely in this distribution.
Injections of the inferior mesenteric artery and celiac axis follow
because the ultimate source is proximal to the ligament of Treitz in
up to 10% of patients with presumed lower gastrointestinal bleeding.
Bleeding can be detected at rates as low as 0.5 to 1.0 mL per minute.
Although extravasation of contrast material is unequivocal evidence
for a bleeding source, angiography also can detect other lesions such
as a tumor blush or angiodysplasia. Extravasation is seen in fewer
than 15% of patients with vascular ectasias; however, angiographic
signs of their presence include a prominent early-lling vein, a vascular tu, or a late-draining vein.
When angiography documents a bleeding site, transcatheter
therapy can be instituted in an attempt to stop the bleeding. e two
alternatives are intra-arterial infusion of vasopressin or transcatheter
embolization of the vessel. Superior mesenteric arterial infusion of
vasopressin reduces splanchnic blood ow by up to 65%, thus, it is
hoped, allowing a hemostatic plug to form in the bleeding vessel.
Vasopressin infusion is initiated at 0.2 units per minute with repeat
angiography performed 20 minutes later to document the eectiveness of the infusion. If necessary, the rate can be increased to 0.4 units
Computed Tomography
phy
per minute, aer which the marginal benet is oset by its adverse
eects. Because cardiac complications are reportedly as high as 43%,
these patients require continuous cardiac monitoring, preferably in
an intensive care unit. Although success rates up to 90% have been
reported, up to 50% of patients will experience recurrent bleeding
upon cessation of therapy. Our experience of a 41% rebleeding rate
has led us to conclude that the major benet of vasopressin is in stabilizing a patient’s clinical situation, thus permitting a semi-elective
resection to be performed.
An alternative to vasopressin infusion is transcatheter embolization of the aected vessel. is technique provides permanent control of the bleeding vessel and avoids the troublesome adverse eects
of vasopressin. Early techniques used temporary agents placed in a
fairly central location so as to spare distal communicating vessels and
permit their eventual recanalization. Although theoretically transcatheter embolization was expected to reduce the complication of
intestinal ischemia, ischemia still occurred in up to 20% of cases.
e development of small-caliber angiographic catheters has
permitted superselective catheterization of peripheral vessels. is
advance has permitted a more selective therapeutic intervention
and has limited the potential for widespread intestinal ischemia.
Platinum-bered coils or polyvinyl alcohol particles are used as
permanent embolic agents. To date, we have used this approach in
nearly 200 patients with angiographically proven lower gastrointestinal bleeding. In our experience, recurrent bleeding aer seemingly
successful selective embolization occurred in approximately 10% of
patients. For these patients, repeat embolization remains an option.
Similarly, approximately 8% of patients at our institution experienced
postembolization ischemia requiring urgent surgical intervention.
Colonoscop
olonoscopy is an extremely valuable diagnostic tool in the evalua-
C
tion of lower gastrointestinal bleeding. With few exceptions, it should
be performed at some time in the evaluation of any patient presenting
with acute rectal bleeding. e major issue relates to timing of the
colonoscopy during the patient’s hospitalization. ere are many proponents of immediate colonoscopy upon admission to the hospital
without a colonic preparation. is approach is theoretically possible
because blood is an excellent cathartic, and early colonoscopy with
“jet” irrigation of the colon has a high likelihood of determining the
site of bleeding. A large amount of residual clot is usually present,
but the bleeding site can be distinguished either by spurting blood or
bright red blood. Blood can travel retrograde up the colon, and thus a
clot in the cecum does not necessarily mean that the bleeder is there.
However, if the blood stops at a certain level, then the bleeding site is
at least distal to that place. Success rates in nding the bleeding site
as high as 80% have been reported, but it should be noted that this
examination is technically very dicult and has several drawbacks.
Even with highly skilled endoscopists performing “emergency” colonoscopy, the cecal intubation rate is less than that for elective procedures. Furthermore, patient instability can severely limit the ability to
admini
reduces the ability to visualize mucosal detail, which is critical in the
diagnosis of angiodysplasia.
A preferable approach is to decide whether a patient has stopped
bleeding early in the evaluation period. If the patient is hemodynamically stable and not passing fresh blood per rectum, the patient is
prepared for an “urgent” colonoscopy. Polyethylene glycol is administered over 4 to 6 hours, preferably through a nasogastric tube if it has
been le in place. A colonoscopy then can be performed in a much
more controlled setting. e patient is now hemodynamically stable
and can be sedated, permitting a safer procedure. Mucosal detail is
usually comparable to that of elective procedures, although highpressure irrigation to remove an adherent clot must be available.
It is unusual to detect an actively bleeding lesion during colonoscopy performed in this setting. However, suspicious lesions other
y
ster sedatives and analgesics. Finally, residual blood markedly
COLON
247
han diverticula have been reported in up to 50% of patients. Neo-
t
plastic lesions can be removed or biopsied at the time of the colonoscopy. Areas of ulceration or active colitis also can be biopsied. Some
controversy exists about whether angiodysplastic lesions that are not
actively bleeding should be treated prophylactically. We treat them
if no other potential bleeding sources are found during the patient’s
evaluation and if there is a high degree of suspicion that the vascular
ectasia has recently bled. When numerous nonbleeding angiodysplastic lesions are present, their distribution is noted and no active treatment is undertaken. e method of coagulation that is preferred in
our gastrointestinal unit is to use the heater probe to cauterize around
the lesion and nally to cauterize the central area. Care is taken to use
low-power settings, especially in the right colon, which has a relatively thin wall. Other methods of coagulation that can be utilized
are bicap electrocautery, needle injection, argon plasma coagulation,
and neodymium: yttrium-aluminum-garnet (Nd:YAG) laser therapy.
When a diverticulum has stigmata of bleeding, endoscopic clipping
has become a favored treatment. Typically, epinephrine is injected
into the diverticulum to evert it for better access. is maneuver is
then followed by clipping of the vessel or the entire diverticular orice. Tattooing of suspected bleeding sites is also recommended for
future localization should recurrent bleeding occur.
It is important to perform colonoscopy in all patients who have
undergone therapeutic angiography. Although the patient may have
stopped bleeding aer either administration of vasopressin or embolization, there is a 5% to 30% incidence of neoplastic lesions in this
setting. Furthermore, the mucosa can be evaluated for evidence of
ischemia, especially if abdominal pain or tenderness develops.
SURGER
M
ost patients with lower gastrointestinal bleeding stop bleeding
spontaneously and never require surgery. Surgery is reserved for the
10% to 25% of patients who continue to hemorrhage despite nonoperative attempts to control bleeding or who have massive repeat
episodes of bleeding. It has been shown that patients requiring four
or more units of blood in the rst 24 hours of treatment have a 50%
chance of requiring an operation. However, because there are no
absolute predictors of who will require surgery for lower gastrointestinal bleeding upon admission, all patients with a massive hemorrhage should be evaluated and treated as though they may eventually
require exploration and bowel resection.
Every eort should be made to localize the bleeding source preoperatively. If the patient is stable, as many investigations as necessary
should be used to accurately localize the source of bleeding and guide
surgical treatment. Not only is blind laparotomy of a bleeding patient
a frustrating and oen futile exercise, it is also dangerous. Emergency
colectomies for nonlocalized bleeding are associated with a mortality
rate of 10% to 30%, and if a segmental resection is performed in this
setting, the recurrence rate of bleeding is as high as 33%. Subtotal colectomies have become the preferred option for nonlocalized bleeding;
however, this option should still be the last resort. In an emergency,
a subtotal colectomy is performed without an anastomosis, with an
end ileostomy. en, if recurrent bleeding occurs, it will come from
either the stoma or the rectum. e alternative, a total abdominal colectomy with ileorectostomy, can be a debilitating procedure in the
older population, for whom it is frequently necessary. Frequent loose
stools associated with varying degrees of incontinence can severely
aect quality of life. Moreover, creation of an anastomosis within the
setting of an acute gastrointestinal bleed is contraindicated.
During the past 15 to 20 years, the ability to localize sites of lower
gastrointestinal hemorrhage preoperatively has improved greatly,
reducing the need for blind resections. A subtotal colectomy should
be reserved for patients with signicant recurrent bleeding in whom
repeated attempts to localize bleeding have failed and in whom gastric,
small bowel, and rectal sources have been ruled out. Patients in this situation may benet from intraoperative enteroscopy prior to resection.
Y
hen the bleeding site has been localized, segmental resection
W
is the preferred treatment option. e mortality rate in this setting
is less than 10%, and studies have demonstrated rates of rebleeding ranging from 0 to 14%. e decision to perform an anastomosis
depends on intraoperative conditions, as well as the patient’s stability
and comorbid conditions. Of these factors, continued hemodynamic
instability remains the most important determinant in the performance of a diverting ostomy at the time of the operation. Because
many of these patients are older and have coexistent disease, prolonging the operation and creating a risky anastomosis is not wise. Should
the situation be equivocal, performing a primary anastomosis with a
temporary proximal diverting ileostomy is a useful alternative.
e surgeon is occasionally faced with the dilemma of the patient
who has had bleeding localized to the right colon but also has extensive le-sided diverticulosis. e option of a subtotal colectomy
is considered, but the most appropriate procedure in this setting
remains a right hemicolectomy. Multiple studies have shown that the
rebleeding rate from le-sided diverticulosis is quite low. An alternative consideration in such circumstance is the creation of either an
end colostomy or ileostomy. e theoretical advantage of this technique is that it oen can be performed laparoscopically with minimal
morbidity to the patient and can facilitate more denitive localization
of an uncertain bleeding source. Using this technique, an ostomy is
created and the patient is then observed. When recurrent bleeding
occurs, a higher degree of certainty regarding its source is based on
whether the bleeding is from the ostomy (a proximal source) or the
rectum. Although described as a treatment for gastrointestinal bleeding, this operative technique likely plays a minimal role in the setting
of life-threatening hemorrhage because it is not therapeutic. Rather,
this technique may be of some utility in the diagnosis of intermittent
recurrent gastrointestinal bleeding. In our experience, if a patient has
recurrent bleeding but remains hemodynamically stable, waiting and
permitting successful localization in other more conventional ways
provides an overall benet.
THE PR
OBLEM PATIENT:
INTERMITTENT RECURRENT
GASTROINTESTINAL BLEEDING
O
ccasionally, patients experience acute, self-limited gastrointestinal bleeding from a source that cannot be localized with multiple
diagnostic studies. It must be emphasized that as long as the patient
remains hemodynamically stable, continued diagnostic evaluation
is indicated. Blind exploration has virtually no role in this setting.
Bleeding scans, angiography, or endoscopic procedures may need to
be repeated several times. For patients who do not bleed massively
and have signicant comorbidities, conservative treatment with
intermittent transfusions ultimately may be the most appropriate
course.
One of the challenges in the evaluation of recurrent gastrointestinal bleeding has been the lack of eective investigations for evaluation of the small bowel. e introduction of video capsule endoscopy
and spiral enteroscopy represents a signicant technological advance.
Video capsule endoscopy facilitates the successful identication of
obscure bleeding sites that have otherwise been dicult to detect.
is evaluation has been especially benecial in diagnosing abnormalities of small bowel mucosa, specically ectasias, which are the
most common source of lower gastrointestinal bleeding when other
tests prove to be negative. More recently, the development of spiral
enteroscopy has led to a signicant change in the treatment algorithm for small bowel bleeding. Prior to the development of this
technique, endoscopic treatment of small bowel bleeding was limited
to intestine accessible by push enteroscopy and retrograde ileoscopy.
In combination with capsule endoscopy, spiral enteroscopy now
provides the potential for treatment. Reported diagnostic yield for
spiral enteroscopy ranges from 65% to 80%, with the most common
disease being small bowel angioectasia, inammation, and neoplasia.
248
Lo
wer Gastrointestina
L HemorrHaGe
rgon plasma coagulation ablation is a suitable treatment for most of
A
these lesions. As a result, these noninvasive modalities have largely
replaced surgery, thereby resulting in a signicant change in the diagnosis and management of recurrent gastrointestinal bleeding.
As a last resort, either provocative angiography or intraoperative
enteroscopy can be performed. Provocative bleeding studies combine
the use of visceral angiography with the intra-arterial administration
of vasodilators or anticoagulants. A review of published results shows
that this technique can increase the yield of positive angiograms
from 32% to 65%. Despite the improved success, the overall diagnostic benet of provocative angiography remains low, with bleeding
identied in only a small proportion of patients. Additionally, caution
must be used, with the patient’s understanding that immediate surgical exploration may be required.
Alternatively, although operative enteroscopy is technically difcult, success rates of greater than 50% in nding and treating the
cause of bleeding have been reported. Unlike conventional colonoscopy, the bowel mucosa should be inspected in an antegrade fashion because signicant trauma can occur to the bowel wall, thereby
obscuring visualization of potential lesions. An advantage of this
echnique is the ability to transilluminate the bowel, thereby poten-
t
tially demonstrating mucosal lesions. With current advances in
endoscopy, however, the role for this surgical technique has markedly
diminished.
u
S
B
Browder W, Cerise EJ, Litwin MS. Impact of emergency angiography in mas-
Lewis BS, Wenger JS, Waye JD. Small bowel enteroscopy and intraoperative
Pennoyer WP, Vignati PV, Cohen JL. Management of angiogram posi-
Zink AI, Ohki SK, Stein B, etal. Noninvasive evaluation of active lower gas-
S t
g g e
oley SJ, Brandt LF. Vascular ectasias of the colon—1986. Dig Dis Sci.
1986;31(suppl):265–425.
sive lower gastrointestinal bleeding. Ann Surg. 1986;204:530–536.
enteroscopy for obscure gastrointestinal bleeding. Am J Gastroenterol.
1991;86:171–174.
tive lower gastrointestinal hemorrhage in the lower gastrointestinal
tract in adults: diagnostic imaging and interventions. Am J Roentgenol.
1993;161:703–711.
trointestinal bleeding: comparison between contrast-enhanced MDCT and
99mTc-labeled RBC scintigraphy. Am J Roentgenol. 2008;191(4):1101–1114.
e d
e
R
a d i n g
B
L
O
Da
vid P. O’Brien, Kim C. Lu, and Mark H. Whiteford
ODUCTION
INTR
arge bowel obstruction results from a narrowing of the colorectal
A l
lumen that restricts passage of gas and stool. It is a relatively common
surgical emergency. Because the condition may be the result of many
combinations of causes, locations, and settings, each case is unique,
making the choice of treatment challenging.
e most common cause of large bowel obstruction is colorectal
adenocarcinoma, which accounts for more than 50% of cases. Most
obstructions occur on the le side of the colon because the lumen
is more narrow there and the stool is more solid. e age at presentation parallels that of colorectal cancer, with most patients in
the seventh decade of life. Other causes of large bowel obstruction
include carcinoma of noncolorectal origin, diverticulitis, volvulus,
and inammatory bowel disease (Box 51-1). Iatrogenic causes of
obstruction are the ischemia that may follow surgery, an anastomotic stricture, and radiation. A number of attempts have been
made to classify large bowel obstruction, but the aim of treatment in
each patient is to safely relieve the obstruction while attempting to
preserve normal bowel function. Urgent surgery is oen performed
under suboptimal conditions and includes a bowel resection and
then creation of either a temporary or permanent stoma. Newer
techniques, including temporary placement of an endoluminal
stent, have permitted conversion of an emergency procedure into
an elective operation, lowering risks and enhancing recovery. is
delay or bridge may be critical for patient stabilization and optimization, delivery of neoadjuvant therapies, and minimizing the need
for a stoma.
CLINIC
AL AND DIAGNOSTIC
EVALUATION
S
ymptoms of a large bowel obstruction range from mild to severe
depending on the degree of obstruction and the length of time it has
been present. Most patients rst note a change in caliber or a decrease
in the volume of stool. ey may report constipation. Abdominal distension, associated with bloating and cramping abdominal pain, is a
sign of progressive obstruction. As the obstruction worsens, patients
become reluctant to eat or drink and are prone to dehydration. In
extreme cases, patients may present with peritonitis and/or hemodynamic collapse from colonic ischemia or perforation. Patients presenting with a more chronic obstruction oen have weight loss and
experience malnutrition.
e goal of the initial evaluation should be to dierentiate a complete obstruction with possible ischemia and impending perforation
from a stable, partial obstruction. A complete history and physical
examination should be performed, including a review of prior radiographic studies and endoscopic procedures, including water-soluble
or barium enema studies, computed tomography (CT) scans of the
abdomen and pelvis, exible sigmoidoscopy, and colonoscopy.
e history can identify any potential precipitating factors, such
as abdominal surgery, constipation, bowel obstruction, or specic
conditions such as colorectal neoplasia, diverticulitis, and inammatory bowel disease. A detailed history of changing bowel habits
helps assess the acuity of the presentation, and the ability to pass gas
means that the presentation is likely not urgent. Rectal bleeding is
an important clue that may indicate cancer. A physical examination
should focus on vital signs, the general appearance of the patient,
and a careful abdominal examination. Inspection may reveal distension, and percussion conrms tympani. Distal colonic obstruction causes the transverse colon to distend, which is obvious in slim
patients. Volvulus can produce massive distension, and tenderness
over the colon is concerning. A thorough rectal examination is performed. In the absence of peritonitis, abdominal imaging should be
performed, and in some cases, more than one imaging study may
be required. In reality, many patients presenting via the emergency
department have already had a CT scan of the abdomen and pelvis, but a plain abdominal radiograph can be performed quickly, is
inexpensive, can usually dierentiate large bowel from small bowel
obstruction, may demonstrate free air, and can suggest a specic
diagnosis such as volvulus. It will show the diameter of the cecum,
which is important because a large cecal diameter is associated with
preferentially increased wall tension for a given intraluminal pressure. Cecal dilatation above 9 cm carries an increased risk of perforation and death. Although such information will assist in triaging
and expediting care, plain lms may not conrm a specic diagnosis, and thus more testing may be required. A water-soluble contrast enema study, which can be performed relatively quickly and
is inexpensive, is eective in locating the site and cause of obstruction, especially distal obstruction. It also can exclude nonanatomic
obstructions such as colonic pseudo-obstruction. In fact, only 60%
to 63% of mechanical obstructions suggested by plain radiographs
are conrmed by a water-soluble enema. Limitations of water-soluble contrast enemas are that they miss small nonobstructing lesions
and provide limited or no information about the bowel proximal to
the level of obstruction (Fig. 51-1).
In stable patients, a CT scan can provide more information
than either plain films or a contrast enema. CT scans can confirm
the diagnosis of large bowel obstruction and pseudo-obstruction
in more than 90% of patients. Furthermore, a CT scan may identify the location and length of the stricture, as well as evidence
of inflammation/abscess, local visceral invasion, and the potential
cause. CT also excludes or confirms the presence or absence of
metastases and carcinomatosis, and it provides information about
the more proximal large and small bowel. CT colonography could
also play a role in evaluating patients whose preoperative colonoscopy was incomplete by assisting in the detection of proximal
synchronous colon cancers. This information could alter surgical
management. However, CT colonography is most accurate after
full colonic preparation, and thus its application is often limited
in these cases.
249
250
BO
B
enign
X 51-1:
Large BoweL oBstruction
Causes of Large Bo
wel Obstruction
• Diverticulitis
ohn
•Cr
•V
•I
•R
alignant
M
•C
•C
•Ga
•C
sease
di
olvulus
schemicstricture
adiationstricture
olorectal
aden
ocarcinoma
arcinomatosis
strointestinalstromaltumor
arcinoidtumor
• L y m p h o m a
xtrinsictumors
•E
History and
physical examination
Blood work
Plain films
Resuscitation
Stable patient
Water soluble contrast
Enema
CT scan
Volvulus
FIGURE 51-1
Carbon dio
En
Initial e
xide; C T, computed tomography.
doscopy is risky in patients with an obstruction because air
ynecologic,
(g
Perforation or
unstable patient
colonoscopy
CO
2
valuation of a large bowel obstruction.
ur
ologic)
Emergent surgery
Malignant or
diverticular stricture
CO2,
insuation during the procedure can result in worsening colonic distension above the blockage. For a distal obstruction, endoscopy can
provide an accurate and histologic diagnosis. It should be performed
with gentle carbon dioxide insuation instead of air to reduce the
risk of barotrauma.
arking is a part of the preoperative preparation. Other complexi-
m
ties, including unresectable tumors and diculties in providing relief
of obstruction in the setting of carcinomatosis and prior colorectal
resection, must be anticipated. e need for a prolonged stay in the
intensive care unit, postoperative mechanical ventilation, a multistage procedure, management of an open abdomen, and other potential complications should be discussed. Unfortunately, much may be
unknown prior to the operation, and it is oen dicult to anticipate
all potential outcomes.
In semi-elective situations, endoscopic treatment options can be
considered. Endoscopic preoperative resolution of the obstruction
may prevent the need for an ostomy and multiple abdominal operations to restore intestinal continuity. Endoscopic decompression and
sigmoid tube insertion should be performed for sigmoid volvulus
if possible. However, endoscopic decompression is less eective for
cecal volvulus, and an operation should be recommended. e use of
stents for the urgent decompression of large bowel strictures is controversial. e stent may serve as either a bridge to denitive surgical
therapy or as palliation in the unt surgical candidate or in the case of
an advanced malignancy. Volvulus and the role of endoscopic stenting in treating large bowel obstruction are discussed in greater detail
later in this chapter.
Perioperative antibiotics and deep vein thrombosis prophylaxis
are administered, and patients are placed in the lithotomy position
because of a possible need for rectal access, intraoperative endoscopy,
and/or on-table colonic lavage. Ureteral catheters should be considered in cases of signicant lower abdominal inammation, bulky pelvic tumors, or tumors overlying the ureters.
In select cases the laparoscopic technique may be used, although
in patients who have markedly dilated bowel, laparoscopy may
not be feasible because of a lack of abdominal domain and risk
of bowel injury. Additionally, laparoscopy is contraindicated in
the unstable patient because it may contribute to hemodynamic
collapse. In cases of malignancy, oncologic principals need to be
followed, including lymphadenectomy and en bloc resection of
involved organs. One of the most dicult intraoperative decisions
can be whether to perform an anastomosis or create a stoma. In
making this decision, the surgeon must consider the underlying
health of the patient, his or her history of radiation and hemodynamic stability, the level of contamination, intestinal viability,
technical feasibility, and the potential need for adjuvant therapies.
No simple algorithm exists for making this decision. Choices for
temporary diversion include an end colostomy or a loop ileostomy.
Because emergency end colostomies sometimes become permanent, a diverting loop ileostomy protecting a distal anastomosis is
preferred. On-table lavage can remove the column of stool proximal to this anastomosis, thus avoiding signicant contamination in
the event of an anastomotic leak.
MALIGNANT AND
BENIGN
OBSTRUCTION
SURGIC
AL MANAGEMENT
Basic surgical principles apply to the initial management of any acute
surgical emergency. ese principles include adequate intravenous
access, rehydration, and correction of electrolyte abnormalities. Some
patients with large bowel obstruction may also have distended small
bowel loops. Nasogastric tube decompression should be performed
if any concern exists about aspiration. During resuscitation, a surgical strategy can be developed, based on history, including endoscopy
and imaging, the patient’s current medical condition, latest imaging
results, and the likely diagnosis. Unstable patients or those with peritonitis require an emergency operation. e patient and family must
be counseled realistically about the aims of the surgery, the alternatives, and the consequences of various possible ndings. Stoma site
tricturing large bowel obstructions may be benign or malignant.
S
Sometimes a denitive diagnosis cannot be made preoperatively, and
in this case, it is prudent to consider cancer as the most likely diagnosis
and conduct an oncologic resection.
If perforation or peritonitis is present, emergency surgery is indicated. In the absence of an emergency, there should be time to obtain
a detailed history, which will help individualize care. e patient and
family should be counseled regarding the risks of routine bowel surgery and the added risk in patients with large bowel obstructions of
having a protracted hospital or intensive care unit course, a permanent colostomy, and mortality (at a rate of nearly 10%). ese risks
are higher in elderly patients and in patients with signicant comorbidity. Preoperative ostomy siting and counseling with a wound
ostomy continence nurse should be performed in anticipation of a
temporary or permanent ostomy.