SMALL BOWEL OBSTRUCTION and post op adhesion

1
SMALL BOWEL
OBSTRUCTION
Dr. Muhedin Admama(GSR3)
7/14/2025

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Introduction
 The earliest response of the proximal
gut to obstruction is
 Increase bowel wall contractility to
overcome the blockage
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Cont…
 Intra-abdominal adhesions related to prior
abdominal surgery
 Account for up to 75% of cases of small
bowel obstruction.
 Over 300,000 patients are estimated to
undergo surgery to treat adhesion-induced
SBO in USA
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Epidemiology
 Small bowel obstruction is a common surgical problem
and
 Accounts for as many as 400,000 hospital admissions
annually, and
 30-40% of these patients will require operative
exploration
 Mechanical small bowel obstruction is the most
frequently encountered surgical disorder of the small
intestine
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Etiologies
a. Intraluminal (e.g., foreign bodies,
gallstones, or meconium)
b. Intramural (e.g., tumors, Crohn’s disease–
associated inflammatory strictures)
c. Extrinsic (e.g., adhesions, hernias, or
carcinomatosis)
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Cont…
 Less prevalent etiologies for small bowel
obstruction include
Hernias
Malignant bowel obstruction
Crohn’s disease
 The frequency with which obstruction related to
these conditions is encountered varies according
to the patient population and practice setting
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Cont…
 Cancer-related small bowel obstructions are
commonly due to
Extrinsic compression or
Invasion by advanced malignancies arising in organs
other than the small bowel
Few are due to primary small bowel tumors
 The most commonly encountered etiologies of
SBO
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Cont…
 Congenital abnormalities capable of
causing small bowel obstruction usually
become evident during childhood
 They sometimes elude detection and are
diagnosed for the first time in adult
patients presenting with abdominal
symptoms
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Cont…
 Intestinal malrotation and midgut
volvulus should not be forgotten
When considering the differential diagnosis
of adult patients with SBO
 Especially those without a history of
prior abdominal surgery
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Cont…
 A rare etiology of obstruction is the superior
mesenteric artery syndrome
 Characterized by compression of the third portion
of the duodenum by the SMA
 As it crosses over this portion of the duodenum
 This should be considered in young asthenic
individuals
 Who have chronic symptoms suggestive of proximal
small bowel obstruction
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Pathophysiology
 With onset of obstruction, gas and fluid
accumulate within the intestinal lumen
proximal to the site of obstruction
 The intestinal activity increases to overcome
the obstruction
Accounting for the colicky pain and the diarrhea
that some experience even in the presence of
complete bowel obstruction
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Cont…
 Most of the gas that accumulates originates
from swallowed air
Although some is produced within the intestine
 The fluid consists of swallowed liquids and
gastrointestinal secretions
Obstruction stimulates intestinal epithelial
water secretion
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Cont…
 Dilatation and lack of contractility
may allow water and electrolytes to
accumulate proximal to the obstruction
 Significant third space losses in
addition to vomiting may result in
Marked dehydration and hypovolemia
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Cont…
 Metabolic derangement may be significant,
and depends on the level of the obstruction
 Proximal obstruction may result in
Hypochloremia
hypokalemia, and
metabolic alkalosis
 Concurrent, persistent vomiting can exacerbate these
alterations
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Cont…
 Obstruction of the distal small bowel
results in a larger capacitance effect
with enhanced volume loss
 Electrolyte disturbances may be
somewhat less severe
However, significant hypovolemia and
Even renal damage can occur
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Cont…
 Obstruction provokes a profound
change in the flora of the small intestine
 With stasis permitting
Overgrowth of the few native species
Reverse peristalsis from the colonic
microbiota
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Cont…
 With obstruction, the luminal flora of
the small bowel, which is usually sterile,
changes and
 A variety of organisms have been
cultured from the contents
 Translocation of these bacteria to
regional lymph nodes has been
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Cont…
 These are most commonly
Escherichia coli
Streptococcus
Faecalis
Klebsiella species
 Overgrowth can occur rapidly
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Cont…
 Even prior to frank perforation with gross
contamination
There is evidence that bacteria can translocate
through the intestinal wall and
May well contribute to a deteriorating sepsis
picture
If the treatment of initial obstruction is delayed
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Cont…
 With ongoing gas and fluid
accumulation, the bowel distends and
intraluminal and intramural pressures
rise
 The intestinal motility is eventually
reduced with fewer contractions
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Cont…
 If obstruction is not relieved and these
processes continue volume loss and abdominal
distention will result in
Decreased venous return
Diapragmatic elevation
Compromised ventilation
 All of which will exacerbate the symptoms of an
acute abdomen
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Cont…
 If the intramural pressure becomes high
enough
Intestinal microvascular perfusion is
impaired leading to intestinal ischemia,
and, ultimately, necrosis
 This condition is termed strangulated
bowel obstruction
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Cont…
 With partial SBO, only a portion of the
intestinal lumen is occluded
Allowing passage of some gas and fluid
The progression of pathophysiologic
events occur more slowly than with
complete SBO
Development of strangulation is less likely
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Cont…
 A particularly dangerous form of bowel obstruction is
closed loop obstruction
 In which a segment of intestine is obstructed both
proximally and distally (volvulus)
 The accumulating gas and fluid cannot escape either
proximally or distally from the obstructed segment
 This leading to a rapid rise in luminal pressure and a
rapid progression to strangulation
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CLINICAL PRESENTATION AND DIAGNOSIS
CLINICAL FINDINGS
 The symptoms of small bowel obstruction are
Colicky abdominal pain
Nausea
Vomiting
Obstipation
 Vomiting is a more prominent symptom with
proximal obstructions than distal
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Cont…
 Character of vomitus is important as with
bacterial overgrowth
 The vomitus is more feculent, suggesting a more
established obstruction
 Continued passage of flatus and/or stool beyond
6-12 hrs after onset of symptoms is characteristic
of partial rather than complete obstruction
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Cont…
 The signs of SBO include abdominal
distention
Which is most pronounced, If the site of
obstruction is in the distal ileum and
May be absent if the site of obstruction is
in the proximal small intestine
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Cont…
 Bowel sounds
May be hyperactive initially
In late stages of bowel obstruction, minimal bowel
sounds may be heard
 Laboratory findings reflect intravascular volume
depletion
Hemoconcentration and electrolyte abnormalities
 Mild leukocytosis is common
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Cont…
 Features of strangulated obstruction
include
Abdominal pain often disproportionate to
the degree of abdominal findings
Suggestive of intestinal ischemia
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Cont…
 Patients often have
Tachycardia
Localized abdominal tenderness
Fever
Marked leukocytosis
Acidosis
 Any of these findings should alert the clinician to the
possibility of strangulation and the need for early
surgical intervention
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Cont…
 A septic picture raises the more ominous
diagnosis of strangulated bowel or leak
 Both result in a more seriously ill patient whose
complication rate and
Mortality can be worsened by a delay in diagnosis
 Bowel wall integrity can be compromised by a
folding or knuckling of the bowel from adhesion
or hernia
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Cont…
 Additionally, patients prone to arterial
emboli can have mesenteric ischemia
 Present with an ileus/obstruction picture
 In patients with strangulation or leakage
 The WBC can be elevated along with
serum lactate levels
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Cont…
 Abdominal tenderness and rebound are usually
more pronounced than in simple mechanical
obstruction
 Bowel sounds are usually diminished or absent
 In all cases where obstruction or strangulation
is suspected, a rectal exam must be performed
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Diagnosis
 The diagnostic evaluation should focus on the
following goals:
a. Distinguish mechanical obstruction from ileus
b. Determine the etiology of the obstruction
c. Discriminate partial from complete obstruction,
and
d. Discriminate simple from strangulating
obstruction
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Cont…
 The radiologic assessment of these patients must
focus on several important questions:
1) Is the small bowel obstructed
2) What is the severity of the bowel obstruction?
3) Where is the obstruction located?
4) What is the etiology of the obstruction?
5) Is there a closed-loop obstruction?
6) Is bowel ischemia or strangulation present?17
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Cont…
 The diagnosis of SBO is usually confirmed with
radiographic examination
 The abdominal series consists of
I. A radiograph of the abdomen with the patient in a
supine position
II. A radiograph of the abdomen with the patient in an
upright position
III. A radiograph of the chest with the patient in an upright
position
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Cont…
 The finding most specific for SBO is the
triad of
Dilated small bowel loops (>3 cm in
diameter)
Air-fluid levels seen on upright films, and
A paucity of air in the colon
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Cont…
 The sensitivity of abdominal radiographs in
the detection of small bowel obstruction
ranges from 70-80%
 Specificity is low because ileus and colonic
obstruction can be associated with findings
 That mimic those observed with small
bowel obstruction
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Cont…
 False-negative findings on radiographs
can result when
The site of obstruction is in the proximal
small bowel
The bowel lumen is filled with fluid but no gas
There by preventing visualization of air-fluid
levels or bowel distention
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Cont…
 The latter situation is associated with
closed-loop obstruction
 Despite these limitations
Abdominal radiographs remain an
important study in pts with suspected small
bowel obstruction because of their
widespread availability and low cost
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Cont…
 CT scanning is becoming increasingly
the imaging test of choice for pts with
SBO
 It is ideally done with oral contrast
 CT is 80-90% sensitive and 70-90%
specific in the detection SBO
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Cont…
 The findings of SBO include a
Discrete transition zone with dilation of
bowel proximally
Decompression of bowel distally
Intraluminal contrast that does not pass
beyond the transition zone
Colon containing little gas or fluid
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Cont…
 CT scanning may also provide evidence for the
presence of closed loop obstruction and strangulation
 Closed-loop obstruction is suggested by the presence
of a
U-shaped or C-shaped dilated bowel loop associated with
a radial distribution of mesenteric vessels converging
toward a torsion point
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Cont…
 Strangulation is suggested by
Thickening of the bowel wall
Pneumatosis intestinalis (air in the bowel wall)
Portal venous gas
Mesenteric haziness
Poor uptake of intravenous contrast into the
wall of the affected bowel
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Cont…
 CT scanning also offers a global evaluation of
the abdomen and
 May therefore reveal the etiology of obstruction
 This feature is important in the acute setting
When intestinal obstruction represents only one of
many diagnoses in patients presenting with acute
abdominal conditions
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Cont…
 The CT scan is usually performed after
administration of oral water-soluble contrast or
diluted barium
 The water-soluble contrast has been shown to have
prognostic and therapeutic values too
 Several studies and several subsequent meta-
analysis have shown that water-soluble contrast
could in fact have therapeutic and prognostic value
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Cont…
 The appearance of the contrast in the
colon within 24 hrs of administration is
predictive of nonsurgical resolution of
bowel obstruction
Sensitivity of 92% and a specificity of 93%
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Cont…
 A limitation of CT scanning is its low sensitivity
(<50%) in the detection of low-grade or partial
A subtle transition zone may be difficult to identify in
the axial images obtained during CT scanning
 In such cases, contrast examinations of the
small bowel, either small bowel series (small
bowel follow-through) or enteroclysis, can be
helpful
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Cont…
 For standard small bowel series,
contrast is swallowed or instilled into
the stomach through NGT
 Abdominal radiographs are then taken
serially as the contrast travels distally in
the intestine
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Cont…
 Although barium can be used, water-soluble contrast
agents
Gastrograffin, should be used if the possibility of intestinal
perforation exists
 These examinations are more labor-intensive and less
rapidly performed than CT scanning
 But may offer greater sensitivity in the detection of
luminal and mural etiologies of obstruction, such as
primary intestinal tumors
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Cont…
 For enteroclysis, 200-250 mL of barium followed
by 1-2 L of a solution of methylcellulose in water
is instilled into the proximal jejunum by NGT
 The double contrast technique used in
enterocolysis permits
Better assessment of mucosal surface and
Detection of relatively small lesions, even through
overlapping small bowel loops
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Cont…
 Enterocolysis is rarely performed in the acute
setting
 But offers greater sensitivity than small bowel
series in the detection of lesions that may be
causing partial small bowel obstruction
 Recently, CT enterocolysis has been used, and
 It was reported to be superior to plain X-ray small
bowel contrast studies
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Therapy
 SBO is usually associated with a marked depletion of
intravascular volume due to
 Decreased oral intake
 Vomiting
 Sequestration of fluid in bowel lumen and wall
 Therefore, fluid resuscitation is integral to treatment
 Isotonic fluid should be given intravenously, and
 An indwelling bladder catheter may be placed to monitor
urine output
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Cont…
 Central venousor pulmonary-artery catheter
monitoring are not generally indicated
Unless the patient has underlying cardiac disease
and severe dehydration
 Broad-spectrum antibiotics are not indicated
Unless there is concern for bowel ischemia and
surgery is planned
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Cont…
 The stomach should be continuously
evacuated of air and fluid using NGT
 Effective gastric decompression
decreases
Nausea
Distention
Risk of vomiting
Aspiration
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Cont…
 While a period of close observation and
nonoperative management has been the
mainstay of treatment for partial bowel
obstruction
 The standard therapy for complete small
bowel obstruction has generally been
expeditious surgery
With the dictum that “the sun should never rise
and set on a complete bowel obstruction
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Cont…
 The rationale for favoring early surgical
intervention is to minimize the risk for
bowel strangulation
 Whichh is associated with an increased
risk for morbidity and mortality
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Cont…
 Obstruction prior to the onset of
irreversible ischemia
 Therefore, the goal is to operate
before the onset of irreversible
ischemia
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Cont…
 This treatment approach has, however,
undergone significant reassessment in recent
years
 Many advocating for nonoperative
approaches in management of these patients
After ruled out closed-loop obstruction is and
There is no evidence of intestinal ischemia
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Cont…
 Thus, conservative therapy in the form
of NG decompression and fluid
resuscitation is now commonly
recommended
In the initial management of non ischemic
bowel obstruction
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Cont…
 Nonoperative management has been
documented to be successful in 65-81% of
patients with partial small bowel obstruction
Of those successfully treated nonoperatively
Only 5-15% have been reported to have
symptoms
That were not substantially improved within 48
hrs after initiation of therapy
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Cont…
 Therefore, most pts with partial SBO whose
symptoms do not improve within 48 hrs after
initiation of non operative therapy should be
considered for surgery
 The observation that administration of water-
soluble oral contrast has not only diagnostic
but also therapeutic and prognostic value
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Cont…
 The operative procedure performed for small bowel
obstruction varies according to the etiology of the
obstruction
Adhesions are lysed
Tumors are resected
Hernias are reduced and repaired
 Regardless of the etiology, the affected intestine should
be examined, and
 Nonviable bowel should be resected
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Cont…
 Criteria suggesting viability are
 Normal color
 Peristalsis, and
 Marginal arterial pulsations
 Usually, visual inspection alone is adequate in judging
viability In borderline cases
 A Doppler probe may be used to check for pulsatile flow to
the bowel, and
 Arterial perfusion can be verified by visualizing
intravenously administered fluorescein dye in the bowel
wall under ultraviolet illumination
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Cont…
 In general, if the patient is
hemodynamically stable, short lengths
of bowel of questionable viability
Should be resected, and
Primary anastomosis of the remaining
intestine should be performed
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Cont…
 However, if the viability of a large proportion of
the intestine is in question, a concerted effort to
preserve intestinal tissue should be made
 In such situations, the bowel of uncertain
viability should be left intact and
 The patient reexplored in 24-48 hours in a
“second-look” operation
 At that time, definitive resection of nonviable
bowel is completed
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Cont…
 Successful laparoscopic surgery for bowel
obstruction is being reported with greater frequency
 In a propensity score matched study of patients
 Who underwent adhesiolysis for small bowel
obstruction
The laparoscopic approach was associated with
significantly lower rates of overall complications
Surgical site infections
A shorter length of hospital stay (4 vs. 10 days)
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Cont…
 Since distended loops of bowel can interfere with
adequate visualization, early cases of proximal
 That are likely due to a single adhesive band are
best suited for this approach
 Presence of bowel distention and multiple
adhesions can cause these procedures to be
difficult, with a reported conversion rate of 17-33%
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Cont…
 One of the major concerns with the
laparoscopic approach has been the risk
of iatrogenic bowel injury
 Although the laparoscopic approach
was associated with greater surgical
time
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Outcomes
 The perioperative mortality rate associated
with surgery for non strangulating small
bowel obstruction is less than 5%
With most deaths occurring in elderly
patients with significant comorbidities
 Mortality rates associated with surgery
for strangulated obstruction is higher
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Cont…
 Long-term prognosis is related to the etiology
of obstruction
 Many patients who are treated
conservatively for adhesive small bowel
obstruction do not require future
readmissions
Less than 20% of such patients will have a
readmission over the subsequent 5 years with
another episode of bowel obstruction
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Introduction
 Adhesive small bowel obstruction is one of
the leading causes of surgical emergencies
and
 In particular of surgical emergencies that
require an emergent operations
 In the UK, SBO was the indication for 51%
of all emergency laparotomies
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Cont…
 Seven emergency surgical procedures that account
for 80% of all general surgery emergency
admissions, morbidity, deaths, and healthcare
expenditures in the USA
 Adhesive small bowel obstruction was the most
common diagnosis for both the top 2 (small bowel
resection) and top 5 (adhesiolysis) procedures
 Operative adhesions are the leading cause of small
bowel obstructions, accounting for 60% of cases
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Cont…
 ASBO causes considerable harm
Resulting in 8 days of hospitalization on
average and
Hospital mortality rate of 3% per episode
 Between 20 and 30% of patients with
ASBO require operative treatment
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Cont…
 Length of hospitalization and
morbidity depend on the need for
surgical intervention
 Average hospitalization after
surgical treatment of ASBO is 16 days
5 days following non-operative treatment
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Peritoneal adhesions
 Adhesions is fibrous tissue that connects
surfaces or organs within the peritoneal
cavity that are normally separated
 Such adhesions are the results of a
pathological healing response of the
peritoneum up on injury
As opposed to the normal “ad integrum” repair
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Cont…
 Typical adhesions form after peritoneal injury
from abdominal surgery
 Other conditions that may cause peritoneal injury
resulting in adhesion formation include
Radiotherapy
Endometriosis
Inflammation
Local response to tumors
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Cont…
 Adhesions from a non-operative etiology are
often part of a more complex pathology
 That can cause chronic pain and complications
as the result of adhesions and other
mechanisms
 Management of chronic abdominal
complications by adhesiolysis is controversial
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Adhesive small bowel obstruction
 Adhesions are the single most common
cause for small bowel obstruction
 Definitive confirmation of the adhesive
etiology of bowel obstruction is made
during operative treatment
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Cont…
 Methods to confirm the adhesive etiology of
bowel obstruction non invasively include
History of previous episodes of bowel obstruction
by adhesions or
Exclusion of other causes of bowel obstruction by
imaging (often CT scan)
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Adhesiolysis
 Adhesiolysis refers to releasing adhesions
either by blunt or sharp dissection during
surgery
 It can be the primary indication for an
operation, as in a reoperation for small bowel
obstruction caused by adhesions
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Cont…
 Adhesiolysis is also performed during reoperations
for indications no related to adhesions in order to
obtain sufficient access to the operative field
 Complicated adhesiolysis refers to the event of
inadvertent injury while performing adhesiolysis
 Injuries during adhesiolysis are most frequently
made to the bowel
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These bowel injuries are classified as:
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Epidemiology
 The risk of SBO is highest following
Colorectal
Oncologic gynecological, or
Pediatric surgery
 1 in 10 pts develops at least one episode of
SBO within 3 years after colectomy
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Cont…
 Reoperations for ASBO occur in
 Between 4.2 and 12.6% of pts after pediatric surgery pts
 3.2% of colorectal pts
 Recurrence of ASBO is also frequent
 12% of non-operatively treated patients are readmitted within 1 year
 Rising to 20% after 5 years
 The risk of recurrence is slightly lower after operative
treatment:
 8% after 1 year and
 16% after 5 years
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Classification of adhesions
 The most frequently used classification of adhesions in
general surgery is the adhesion score according to Zühlke et al
 The score is based on the
 Tenacity and
 Some morphologic aspects of the adhesions
 The major drawback to the score is that it does not measure
the extent of adhesions and
 Tenacity of adhesions can vary between different parts of the
abdomen
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Cont…
 The most used grading system in gynecological surgery is
the American Fertility Society (AFS) scor
 The score is designed for grading adhesions in the small
pelvis
 Adhesions are scored for extent and severity at four sites:
Right ovary
Right tube
Left ovary
Left tube
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Cont…
 The scores for the right and left side are summed, and the
final AFS score is the score for the side with the lowest
summed score while discarding the score for the other
side
 Thus, a patient with an AFS score of 0 can still have
adhesions
 Further critiques for this score include a relatively low
inter observer reproducibility
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100
Cont…
 Recently introduced score by the ASBO
working group is the peritoneal adhesion
index (PAI)
 Which measures tenacity on a 1–3 scale at 10
predefined sites, to integrate tenacity and
extent of adhesions in a single score
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Cont…
 This score is the only score that has been
validated to be prognostic for convalescence
after surgery for ASBO and
 The risk of injuries during adhesiolysis
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103
Prevention of adhesion
Surgical technique
 The main principles of prevention of adhesion and
related complications are
Minimizing surgical trauma and
Use of adjuvants to reduce adhesion formation
 Laparoscopy is often believed to reduce adhesion
formation and the risk for ASBO
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104
Cont…
 Important risk factors for aggravated
adhesion formation are worth considering
 One of the most important risk factors is the
foreign body reaction
Starch-powdered gloves
Meshes used for abdominal wall reconstruction
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105
Cont…
 The choice of energy device might also impact
adhesion formation
 Peritoneal injury is
Lower in bipolar electrocautery and ultrasonic
device
Higher in monopolar electrocautery
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106
Cont…
Animal data suggest that both systemic and
intraperitoneal application of antibiotics, and
metronidazole in particular, can reduce adhesion
formation in septic conditions
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107
Adhesion barriers
 Adhesion barriers are adjuvants for peritoneal
administration
 That can effectively reduce adhesion formation.
 Adhesion barriers are produced in several forms:
Solid membranes
Gels
Liquids
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108
Cont…
 The concept behind barriers is that they do not
actively interfere with inflammation and wound
healing
 Rather, they act as a spacer
Which separates injured surfaces of the peritoneum,
Allowing these surfaces to heal without forming
fibrinous attachments which eventually lead to
adhesions
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111
Approach to the patient with ASBO
 The initial diagnosis of ASBO is of the most
importance
 Failure to diagnose or having a delayed
diagnosis represents 70% of malpractice
claims in ASBO
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112
Cont…
 The primary goals in the initial evaluation of
patients in whom adhesive small bowel
obstruction is suspected are
i. Differentiating between ASBO and other causes of
bowel obstruction
ii. Assessing the need for urgent surgical exploration
iii. Identifying and preventing complications from
bowel obstruction
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113
History taking and physical examination
 ASBO is clinically diagnosed in a patient with
Intermittent colicky abdominal pain
Distention, and nausea(with or without vomiting),
With or without absence of stools
• Although diagnosis of small bowel obstruction is
fairly certain in a patient in whom all of these
symptoms are present
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114
Cont…
 In pts with incomplete obstruction, watery
diarrhea may be present
 The presence of watery diarrhea can cause an
episode of ASBO to be mistaken for gastro-enteritis
 Stools might also be present in patients with a
relatively high obstruction who are admitted early
after onset of symptoms
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115
Cont…
 During P/E, signs of peritonitis that might
reveal strangulation or ischemia should be
evaluated
 Differential considerations that can be
assessed during P/E include the presence of
any abdominal wall or groin hernias
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116
Cont…
 The evaluation of ASBO by history taking and
P/E has a low sensitivity for detecting bowel
strangulation and ischemia
 Sensitivity of P/E for detection of
strangulation is only 48%, even in experienced
hands
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117
Laboratory tests
 The minimum of laboratory tests include
Blood count
Lactate
Electrolytes
CRP, and BUN/creatinine
 Laboratory values that might indicate peritonitis are
CRP > 75 and
White blood cell count > 10.000/mm3
 Although sensitivity and specificity of these tests are relatively
low
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118
Cont…
 Electrolytes are often disturbed in patients with
a bowel obstruction
In particular, low values of potassium are frequently
found and need to be corrected
 BUN/creatinine needs to be assessed as patients
with ASBO are frequently dehydrated which
could result in AKI
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119
Imaging studies
Plain X-rays
 The value of plain X-rays complementary to P/E is
limited
 In high-grade obstruction, a triad of multiple air-fluid
levels, distention of small bowel loops, and
 Absence of gas in the colon are pathognomonic for SBO
 but overall sensitivity and specificity of plain x-rays are
low ~70%
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120
Cont…
 A large volume pneumo peritoneum 2 to
bowel perforation in ASBO can also be
detected on plain X-rays
 Preferably by an erect chest X-ray Plain X-rays
 However, do not detect the more early signs
of peritonitis or strangulation
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121
Water-soluble contrast studies
 If the contrast has not reached the colon on
an abdominal X-ray taken 24 h following
administration of the contrast
 This is highly indicative of failure of non-
operative management
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122
Cont…
 CT scans Current helical CT scans not only
have good test characteristics for diagnosing
 but also have approximately 90% accuracy in
predicting strangulation and the need for
urgent surgery
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123
Cont…
 Diagnostic value of CT scan can be enhanced
with the use of water-soluble contract
 As with water-soluble contrast studies,
progress of the contrast can be evaluated by
X-ray at24 h after CT scan
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124
Management
Initial decision making
 Non-operative management should always be
tried in patients with ASBO
Unless there are signs of peritonitis, strangulation,
or bowel ischemia
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125
Cont…
 Although the risk of recurrence is slightly lower after
operative treatment
 This is not a reason to opt for a primary surgical approach
 Morbidity from emergency surgical exploration is high
 There is a considerable risk for bowel injury, and
 Surgical treatment may significantly reduce post-
operative quality of life
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126
Non-operative management
 The cornerstone of non-operative
management is
Nil peros(NPO)
Decompression using a NGT or long intestinal tube
 Non-operative management is effective in
approximately 70–90% of patients with ASBO
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127
Cont…
 Continuing non-operative treatment for more
than 72 h in cases with persistent high output
from a decompression tube,
 But no other signs of clinical deterioration
however, remains subject to debate
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128
Cont…
 Common medical complications in patients
with SBO are
Dehydration with kidney injury
Electrolyte disturbances
Malnutrition
Aspiration
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129
Cont…
Non-operative management: summary
 Evidence for the optimal duration of non-
operative is absent
 But, most authors and the panel consider a
72-h period as safe and appropriate
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130
Operative treatment
1) Laparatomy
2) Laparoscopy
 The potential benefits of laparoscopy include
Less extensive adhesion (re)formation
Earlier return of bowel movements
Reduced post-operative pain, and
Shorter length of stay
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131
Cont…
Operative management: summary
 Laparoscopic surgery has been introduced in recent years
and might decrease morbidity in subgroups of patients
undergoing surgery for ASBO
 The risk of bowel injuries seems higher in laparoscopic
surgery for ASBO
 Therefore, careful selection of patients for laparoscopic
surgery is required
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134
Special patient groups
Young patients
 The risk of adhesion-related complications is life-long
 Although most small bowel obstructions will occur within
the first 2 years after surgery
 New cases continue to develop many years after the
primary operation
 Pediatric patients, who are at the extreme of young age,
have a high risk for adhesion-related complications
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135
 Young patients therefore might have
the highest lifetime benefit from
adhesion prevention
 No trials with adhesion barriers have
been performed in pediatric surgery
After a follow-up of 24 months, 2.0% of pediatric patients operated with adhesion
barrier versus 4.5% of patients operated on without adhesion barrier developed
ASBO
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136
Elderly patients
 Patients with diabetes were shown to suffer
from a
7.5% incidence of AKI and
4.8% incidence of MI
 If the incidence of these complications was
significantly higher when compared to diabetic
patients that were operated within 24 h and non-
diabetic patients with delayed operation
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137
Pregnancy
 SBO in pregnancy is very rare
 But represents an important clinical
challenge with significant risk of fetal
loss
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139
THE END (BOLOGNA GUIDLINE)
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140
Other Causes of SBO
Early postoperative bowel obstruction
 defined by signs, symptoms, and radiographic
signs of SBO
 Occurring within 30 days following surgery
 Maingoats 13th
ed says “6 weaks post operative”
 been reported to occur in 0.7% to 9% of patients,
 With a higher rate in patients undergoing pelvic
surgery, especially colorectal procedures
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141
Cont…
 CT scanning or small bowel series is often
required to make the diagnosis
 Obstruction that occurs in the early
postoperative period is usually partial and
 Only rarely is associated with
strangulation
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142
Cont…
 Therefore, a period of extended non
operative therapy (2–3 wks) consisting
of
Bowel rest
Hydration
TPN administration
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143
 However, expeditious reoperation
should be undertaken without delay if
Complete obstruction is demonstrated
Signs suggestive of peritonitis are
detected
In a series of 180 patients undergoing anterior resection for rectal cancer,
12.8% developed early postoperative bowel obstruction on the median
postoperative day 5, with 4 requiring surgical exploration at a median interval
of 2 weeks from the index case
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144
Cont…
Malignant small bowel obstruction
 Although it often indicates advanced disease with
poor prognosis
 25-33% of patients with a history of cancer
 Who present with SBO have adhesions as the
etiology of their obstruction and
 Therefore should not be denied appropriate
therapy
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145
 Even in cases in which the obstruction is related to
recurrent malignancy
Palliative resection or bypass can be performed
 In select cases these procedures lead to improved quality
of life
In a series of 81 patients with small bowel obstruction, palliation was achieved in
over 80% of patients, with over 70% able to reestablish oral intake. In this series,
the surgical morbidity was high, with 7% developing an enterocutaneous
fistula/anastomotic leak and a 30-day mortality rate of 6%
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146
Cont…
 Patients with obvious carcinomatosis and
multifocal obstruction pose a difficult challenge,
given their limited prognosis
 At the time of surgery, relief of the obstruction
may be best achieved by
 A bypass procedure
 Avoiding a potentially difficult bowel resection
 Even if that is not feasible, a palliative gastrostomy tube
can be considered to help resolve nausea and vomiting
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147
ILEUS AND OTHER DISORDERS OF
INTESTINAL MOTILITY
 Ileus and intestinal pseudo-obstruction
are clinical syndromes caused by
impaired intestinal motility and
 Are characterized by symptoms and signs
of intestinal obstruction in the absence of
lesion-causing mechanical obstruction
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148
Cont…
 Ileus is a temporary motility disorder
That is reversed with time as the inciting
factor is corrected
 Chronic intestinal pseudo-obstruction
Comprises a spectrum of specific disorders
associated with irreversible intestinal
dysmotility
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149
Cont…
 Ileus is a major cause of morbidity in
hospitalized patients
 A degree of intestinal ileus is a normal
physiological response to abdominal
surgery
 Which often resolves quickly without any
long-term sequela
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150
Cont…
 When postoperative ileus is prolonged,
it can cause significant morbidity and cost
 Prolonged postoperative ileus is the
most frequently implicated cause of
Delayed discharge following abdominal
operations
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151
Pathophysiology
 Frequently encountered factors are
Abdominal operations
Infection and inflammation
Electrolyte abnormalities
Drugs
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153
Cont…
 Following most abdominal operations
or injuries
 The motility of the gastrointestinal tract
is transiently impaired
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154
Cont…
 Among the proposed mechanisms
responsible for this dysmotility are
Surgical stress-induced sympathetic reflexes
Inflammatory response mediator release, and
Anesthetic/analgesic side effects
Each of which can inhibit intestinal motility
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155
Cont…
 The return of normal motility generally
follows a characteristic temporal sequence
Small intestinal motility returning to normal
within the first 24 hours after laparotomy
Gastric within by 48 hrs of after laparatomy
Colonic motility returning to normal by 2-5 ds
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156
Cont…
 Since small bowel motility is returned before
colonic and gastric motility
Listening for bowel sounds is not a reliable
indicator that ileus has fully resolved
 Functional evidence of coordinated
Gastrointestinal motility in the form of passing
flatus or bowel movement is a more useful
indicator
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157
Cont…
 Resolution of ileus may be delayed in
the presence of other factors capable of
inciting ileus
Such as the presence of intra-abdominal
abscesses or electrolyte abnormalities
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158
Cont…
 Chronic intestinal pseudo-obstruction
can be caused by a large number of
specific abnormalities affecting intestinal
Smooth muscle
The myenteric plexus
Extraintestinal nervous system
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160
Cont…
 Visceral myopathies constitute a group
of diseases characterized by
Degeneration and fibrosis of the intestinal
muscularis propria
 Visceral neuropathies encompass a
variety of degenerative disorders of the
myenteric and submucosal plexuses
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161
Cont…
 Both sporadic and familial forms of visceral
myopathies and neuropathies exist
 Systemic disorders involving the smooth
muscle such as
Progressive systemic sclerosis
Progressive muscular dystrophy
Neurological diseases
Parkinson’s disease, can also be complicated by chronic
intestinal pseudo-obstruction
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162
Cont…
 Viral infections associated with a cause
of intestinal pseudo-obstruction
Cytomegalovirus
Epstein-Barr virus
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163
Clinical Presentation
 Inability to tolerate liquids and solids by
mouth
 Nausea
 Lack of flatus or bowel movements
 Vomiting and abdominal distension
may occur
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164
Cont…
 Although bowel sound characteristics
are not diagnostic
They are usually diminished or absent
 Hyperactive bowel sounds that usually
accompany mechanical small bowel
obstruction
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165
Diagnosis
 Routine postoperative ileus should be
expected and requires no diagnostic
evaluation
 Definition of prolonged postoperative
ileus has been varied
But generally diagnosed if ileus persists
beyond 5 days postoperatively
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166
A recent global survey synthesized the results of the data to
define
 Postoperative ileus is “interval from surgery until
passage of flatus/stool AND tolerance of an oral diet,”
 With prolonged postoperative ileus being defined as
 “Two or more of nausea/vomiting
 Inability to tolerate oral diet over 24 h,
 Absence of flatus over 24 h,
 Distension
 Radiologic confirmation occurring on or after day 4
postoperatively without prior resolution of postoperative ileus
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167
Cont…
 Prolonged ileus is reported to occur in 10-
15% of patients undergoing intestinal surgery
 Medication lists should be reviewed
 Abdominal radiographs are often obtained
 But the distinction between ileus and
mechanical obstruction may be difficult based
on this test alone
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168
Cont…
 In the postoperative setting
CT scanning is the test of choice
As it can demonstrate the presence of an
intra-abdominal abscess or
Other evidence of peritoneal sepsis that
may be causing ileus and
Can exclude the presence of complete
mechanical obstruction
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169
Cont…
 The diagnosis of chronic pseudo-obstruction is
suggested by clinical features and
 Confirmed by radiographic and manometric
studies
 Diagnostic laparotomy or laparoscopy with full-
thickness biopsy of the small intestine
May be required to establish the specific underlying
cause in cases of suspected neural disorder
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170
Therapy
 The management of ileus consists of
Limiting oral intake and
Correcting the underlying inciting factor
 If vomiting or abdominal distention are
prominent
The stomach should be decompressed using a
NGT
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171
Cont…
 Fluid and electrolytes should be
administered intravenously until ileus
resolves
 If the duration of ileus is prolonged,
total parental nutrition (TPN) may be
required
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172
Cont…
 Given the frequency of postoperative ileus
and its financial impact, many strategies
have been tested to reduce its duration
The administration of NSAID such as
ketorolac and concomitant reductions in
opioid dosing have been shown to reduce the
duration of ileus in most studies
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173
Cont…
 Similarly the use of perioperative thoracic
epidural anesthesia/analgesia with regimens
containing local anesthetics combined with
limitation or elimination of systemically
administered opioids has been shown to reduce
duration of postoperative ileus
 Although they have not reduced the overall
length of hospital stay
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174
Cont…
 limiting intra- and postoperative fluid
administration can also result in reduction of
postoperative ileus and shortened hospital stay
 Early postoperative feeding after GI surgery is
generally well tolerated and can lead to
reduced postoperative ileus and a shorter
hospital stay
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176
For further we will see ERAS Protocol
7/14/2025

177
Cont…
 Administration of alvimopan, a novel,
peripherally active mu-opioid receptor
antagonist with limited oral absorption
 Has been shown to reduce duration of
Postoperative ileus
Hospital stay
Rate of readmissions in several prospective
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178
Cont…
 The therapy of patients with chronic intestinal
pseudo obstruction focuses on palliation of
symptoms as well as
Fluid
Electrolyte
Nutritional management
 Surgery should be avoided if possible
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179
Cont…
 No standard therapies are curative or
delay the natural history of any of the
specific disorders causing intestinal
pseudo-obstruction
 Prokinetic agents, such as
metoclopromide and erythromycin, are
associated with poor efficacy
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180
Cont…
 Patients with refractory disease may require
strict limitation of oral intake and long-term TPN
administration
 Despite these measures, some patients will
continue to have severe abdominal pain or
 such copious intestinal secretions that vomiting
and fluid and electrolyte losses remain substantial
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181
Cont…
 These patients may require a decompressive
gastrostomy or an extended small bowel
resection to remove abnormal intestine
 Small-intestinal transplantation has been applied
in these patients with increasing frequency;
 The ultimate role of this modality remains to be
defined
7/14/2025

182
Reference
 Schwartzs principle of Surgery 11th
ed 2019
 Shackel ford 8th
ed 2019
 Bologna guidline 2018
7/14/2025
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