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ORIGINAL ARTICLE
Sonographic findings predictive of the need for surgical
management in pediatric patients with small
bowel intussusceptions
Yao Zhang & Yu-Zuo Bai & Shi-Xing Li & Shou-Jun Liu &
Wei-Dong Ren & Li-Qiang Zheng
Received: 20 September 2010 /Accepted: 17 January 2011 /Published online: 28 January 2011# Springer-Verlag 2011
Abstract
Purpose This study aims to evaluate ultrasound findingsthat are predictive of the need for surgical management in
pediatric patients with small bowel intussusceptions (SBIs).
Methods A retrospective review of pediatric patients with
SBIs treated from 2004 to 2009 was conducted. Patients
were divided into surgical and non-surgical groups.
Demographic data, ultrasound findings, treatments, and
outcomes were collected and analyzed.
Results There were 56 cases of SBIs in 31 males and 25
females ranging in age from 4 months to 9 years; 39 patients
were managed conservatively and 17 patients underwent
surgery. The mean length and diameter of the intussusception
in the surgical group were 6.53 and 2.78 cm, respectively, and3.21 and 1.81 cm, respectively in the non-surgical group
(both, P <0.001). Multivariate logistic regression analysis
indicated that diameter, length, and thickness of the outer rim
were independent predictors of surgery. Receiver operating
characteristic curve analysis indicated an intussusception
diameter ≥2.1 cm, length ≥4.2 cm, and thickness of the outer
rim ≥0.40 cm were optimal cutoff values for predicting the
need for surgery.
Conclusions A diameter ≥2.1 cm, length ≥4.2 cm,
and thickness of the outer rim ≥0.40 cm predict the needfor surgical management in pediatric patients with SBIs.
Keywords Intussusception . Small bowel intussusception .
Ultrasound . Intestinal diseases . Infants
Introduction
Acute intussusception is the most common condition
causing an acute abdomen in infants, and typical clinical
manifestations include paroxysmal crying, abdominal pain,
abdominal mass, and bloody stool [1]. Intussusceptions are
usually located in the ileocolic region and ileocecal
junction, and these two types comprise approximately
80% of the intussusceptions in pediatric patients [2]. Small
bowel intussusceptions (SBIs) are relatively rare and
accounts for <10% of the intussusceptions in pediatric
patients [2]. Clinical manifestations of SBIs are not typical,
patients may present with non-specific signs and symptoms,
an abdominal mass and bloody stool occur infrequently,
and diagnosis may be delayed resulting in intestinal
necrosis and a potential life-threatening situation [1 – 3].
Ultrasound is highly accurate for the diagnosis of ileocolic
intussusceptions with a reported sensitivity of 98 –
100%, and
the ultrasound detection rate for SBIs is approximately 76%
[4]. Diagnosis of an intussusception is made by the
appearance of characteristic findings on ultrasound [5, 6].
Because some SBIs reduce spontaneously, it is controversial
whether or not surgical treatment is necessary for all cases in
pediatric patients [7, 8]. Doi et al. [8] reported that
spontaneous reduction happens in most cases of SBI in
children, and only clinical observation, rather than surgical
intervention, is needed and has termed these transient
Y. Zhang : S.-X. Li : S.-J. Liu : W.-D. Ren
Department of Ultrasound, Shengjing Hospital,
China Medical University,Shenyang 110004, China
Y.-Z. Bai (*)
Department of Pediatric Surgery,
Shengjing Hospital of China Medical University,
No. 36 Sanhao St, Heping District Shenyang 110004, China
e-mail: [email protected]
L.-Q. Zheng
Department of Library,
Shengjing Hospital of China Medical University,
Shenyang 110004, China
Langenbecks Arch Surg (2011) 396:1035–1040
DOI 10.1007/s00423-011-0742-6
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intussusceptions, benign SBIs. Sönmez et al. [9] consider that
SBIs secondary to Henoch – Schonlein purpura can be reduced
spontaneously, and conservative treatment is feasible. How-
ever, Ko et al. [2] report that persistent SBIs are often
associated with intestinal ischemia, necrosis, and perforation,
and surgical intervention is warranted once diagnosed. Koh et
al. [3] consider that though spontaneous reduction can be
achieved in most cases of SBIs, surgical treatment isinevitable in some patients with intestinal ischemia or a
pathological lead point.
Therefore, it is clinically very important to determine
whether an SBI is likely to reduce spontaneously in order to
avoid complications and perform surgery in a timely
manner, as well as avoid surgery when not necessary. In
the present study, we carried out a retrospective analysis of
pediatric patients with SBIs who required surgery and in
whom the intussusception resolved spontaneously in order
to identify ultrasound characteristics predictive of the need
for surgical management.
Materials and methods
This retrospective study was conducted in the Pediatric
Department of Shengjing Hospital of the China Medical
University. This study was approved by the institutional
review board of the hospital, and the requirement of informed
consent was waived because of its retrospective nature.
The records of pediatric patients (from birth to 14 years of
age) with single SBIs diagnosed by ultrasound who were
admitted between January 2004 and December 2009 were
reviewed. Patients were divided into a group that received
surgery (surgical group) and a group that did not receive
surgery (non-surgical group). In the non-surgical group,
spontaneous reduction was proven by ultrasound, and surgical
intervention was not required. Data extracted from the
medical records and evaluated included patient demographic
characteristics, clinical symptoms and signs, ultrasound
imaging features, operative findings, and treatment outcomes.
Collected ultrasound image data included the location of
the intussusception (left upper quadrant, left lower quad-
rant, right upper quadrant, and right lower quadrant of the
abdomen), length, diameter, thickness of the sheath, the
presence of enlarged lymph nodes (defined as ≥1.0×0.5 cm),
the presence of intestinal expansion (diameter ≥3.0 cm), the
presence of a visible pathological lead point, and the
presence of free fluid in the abdomen. Two physicians,each with more than 5-year experience in reading
pediatric ultrasounds, performed the ultrasounds and
confirmed the diagnoses, i.e., both physicians read each
ultrasound, and agreement between the physicians was
arrived at before a final diagnosis was made. The
diagnosis of SBI was based on the presence of a “target
sign” on cross section and “sleeve sign” on vertical
section in ultrasound images (Figs. 1 and 2). Ultrasound
machines used were either a GE V730 (General Electric
Healthcare, USA) or PHILIPS iu22US (Philips Medical
Systems, Holland), and probes used were a 2 – 5-MHz
convex array probe and a 6 –
12-MHz linear array probe.
Statistical analyses
Categorical data were presented by number and percentage
and tested by chi-square test or Fisher 's exact test.
Continuous data were presented with mean and standard
deviation or median and interquartile range and tested by t
test or Wilcoxon rank sum test. Diameter, length, and
thickness of the outer rim were separately tested in a
logistic regression model adjusted for age, gender, and the
presence of free fluid and enlarged lymph nodes, with
results expressed as a parameter estimate (log odds) and
95% confidence interval (CI) for surgery as the outcome. A
receiver operating characteristic (ROC) was used to
determine an optimal value for deciding whether a SBI
patient required surgery. Data were analyzed using SPSS
15.0 (SPSS Inc., Chicago, IL, USA). A value of P <0.05
was considered to indicate statistical significance.
F ig . 1 a A 2 2 - mo n t h- o l d
female. Ultrasound shows the
“target sign”, and the diameter
of the abdominal mass was
2.8 cm. Ileal intussusception
was confirmed at surgery. b A
2-year-old male with transient
small bowel intussusception.
Ultrasounds show the “target
sign”, and the diameter of the
abdominal mass was 2.0 cm.
The mass had disappeared at
reexamination
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Results
Between January 2004 and December 2009, there were 56
cases of single SBIs diagnosed by abdominal ultrasound
findings of a “target sign” and “sleeve sign”. There were 31
males and 25 females ranging in age from 4 months to9 years. There were 39 patients who were managed
conservatively and did not receive surgery (non-surgical
group), and 17 patients who underwent surgery (surgical
group). Patient data by group are presented in Table 1.
In the surgical group, 14 patients had various degrees of
intestinal obstruction, and symptoms included vomiting,
abdominal distention, and the absence of flatus and
defecation. Bloody stool was present in one case, and plain
abdominal radiograph showed a stepped liquid – gas inter-
face. There were six secondary SBIs (four associated with
intestinal polyps and two ileocolic intussusceptions sec-
ondary to an inverted Meckel's diverticulum), five postop-
erative SBIs, and four were primary SBIs without an
identifiable cause. In two cases, preoperative ultrasound
showed an SBI, and repeated ultrasound scanning was
carried out every 2 – 3 h in which a SBI was observed every
time; however, no SBI was found during exploratory
laparotomy. Intraoperative manual reduction of the SBI
was performed in the 15 cases in which an SBI was found
during surgery. In addition, polypectomy was performed infour cases, and Meckel's diverticulum resection was
performed in two cases. Intestinal necrosis occurred in
one case, and resection and anastomosis were performed.
Ultrasound-guided hydrostatic reduction using a saline
enema was attempted in five cases and failed in four cases.
In one case, recurrence occurred after successful reduction,
and surgical treatment was carried out after the intussus-
ception developed four times in 2 days. Surgery and
postoperative recovery were without complications in all
cases, and patients were discharged in good condition.
In the non-surgical group, the main clinical manifesta-
tion was diarrhea in 21 cases, paroxysmal crying andabdominal pain in 11, and vomiting in 15. In five cases,
there were no clinical symptoms, and the SBIs were found
F ig . 2 a A 2 2 - mo n t h- o l d
female. Ultrasounds show the
“sleeve sign”, and the length of
the mass was 5.5 cm. Ileal
intussusception was confirmed
at surgery. b A 3-year-old male
with transient small bowel
intussusception. Ultrasounds
show the “sleeve sign” on ver-
tical section, and the length of the mass was 2.1 cm. The mass
had disappeared at reexamina-
tion
Non-surgery group (n=39) Surgery group (n=17) P value
Female (n, %)a 19 (18.7) 6 (35.3) 0.3528
Age (months) b 24 [21 – 48] 22 [9 – 48] 0.2861
Abdominal pain 21 17
Vomiting 15 15
No flatus or defecation 2 14
Bloody stool 0 1
No clinical symptoms 5 0Secondary small bowel
intussusception
0 6
Diameter (cm) b 1.81±0.28 2.78±0.41 <0.0001*
Length (cm) b 3.21±0.86 6.53±2.60 <0.0001*
Thickness of outer rim (mm) b 0.35±0.05 0.55±0.10 <0.0001*
Location (LU/LL/RU/RL)a 24:6:8:1 2:6:5:4 <0.0001*
Free fluid present (n, %) 2 (5.1) 13 (76.5) <0.0001*
Enlarged lymph nodes present (n, %)a 15 (42.2) 7 (41.2) 0.8483
Bowel dilatation present (n, %)a 2 (5.1) 11 (64.7) <0.0001*
Table 1 Patient demographic
and sonographic data
LU left upper, LL left lower, RU
right upper, RL right lower
* P <0.05, statistical significancea
Chi-square test or Fisher 's exact
test b
Median [interquartile range],
Wilcoxon rank sums test, or
mean±standard deviation, t test
Langenbecks Arch Surg (2011) 396:1035–1040 1037
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incidentally (two underwent ultrasound reexamination after
abdominal tumor resection, one underwent ultrasound
reexamination after appendectomy, and two underwent
routine abdominal ultrasound examination after a car
accident). No abdominal distention, abdominal mass,
bloody stool, or signs of acute intestinal obstruction were
noted in any of the patients in this group. Spontaneous
reduction of the SBI was proven by ultrasound in all 39 patients. In 6 cases, spontaneous reduction was observed
during scanning, in 31 cases, reduction occurred 30 – 60 min
after ultrasound scanning, and in 2 cases, reduction
occurred 2 – 3 h after scanning. Abdominal ultrasound,
performed 12 – 24 h after the apparent reduction in all
patients, revealed no signs of SBI. In 11 patients, carbon
powder was administered orally, and discharge through the
anus 8 – 24 h later was noted, indicating that the SBI had
resolved.
Ultrasound findings of both groups are presented in
Table 1. No pathologic lead point was found in any patient
in either group. The mean length and diameter of theintussusception in the surgical group were 6.53 and
2.78 cm, respectively, and both were statistically greater
than the corresponding measurements in the non-surgical
group (3.21 and 1.81 cm, respectively; both, P <0.001).
Results of the multivariate logistic regression analysis
are presented in Table 2, and indicate that diameter, length,
and thickness of the outer rim were all independent
predictors of the necessity of surgery with estimate values
(95% CIs) of 6.2 (1.5 – 11.0), 2.4 (0.7 – 4.1), and 24.2 (4.6 –
43.8), respectively. Age, gender, and the presence of free
fluid, enlarged lymph nodes, and bowel dilatation had no
independent correlation with whether or not a patient
required surgical treatment.
ROC curve analysis was performed to determine the best
critical values for diameter, length, and thickness of the
outer rim for evaluating whether or not an SBI patient
requires surgical management, and results are presented in
Fig. 3 and Table 3. The diameter was 2.1 cm (area under
the ROC curve [AUC] 0.973, 95% CI 0.939 – 1.000), the
length was 4.2 cm (AUC 0.964, 95% CI 0.920 – 1.000), and
the thickness of the outer rim was 0.40 cm (AUC 0.968,
95% CI 0.929 – 1.000). The sensitivity, specificity, positive
predictive value, and negative predictive value of the values
are shown in Table 3. If the length of the intussusception
is ≥4.2 cm, the sensitivity and specificity for the need of
surgical management are 94.1% and 84.6%, respectively.
Discussion
In the present study, we retrospectively analyzed the
clinical manifestations and ultrasound imaging features of
all cases of SBIs managed surgically and conservatively.
Our results showed that diameter, length, and thickness of
the outer rim of the intussusception were all independent
predictors of the need for surgery. ROC analysis indicated
that when the length of intussusception is ≥4.2 cm, the
sensitivity and specificity of the need of surgical manage-
ment are 94.1% and 84.6%, respectively.
Diagnosis of most SBIs relies on ultrasound scanning,
and types of intussusceptions can be readily distinguished
[5, 6, 10]. In addition, with the development and wide
Fig. 3 Diagnostic accuracy of diameter, length, and thickness of the
outer rim on a continuous scale in the prediction of surgery using a
receiver operating characteristic curve. Diameter: AUC1 (95% CI),
0.973 (0.939 – 1.000), P <0.001. Length: AUC2 (95% CI), 0.964
(0.920 – 1.000), P <0.001. Thickness of the outer rim: AUC3 (95%
CI), 0.968 (0.929 – 1.000), P <0.001. AUC area under the curve, CI
confidence interval
Table 2 Parameter estimates of logistic regressions and 95% CIs for
surgery as a function of diameter, length, and thickness of the outer rim, adjusted by age, gender, free fluid present, enlarged lymph nodes
present, and bowel dilatation present
Ultrasound feature Estimates 95% CI P value
Diameter 6.2 (1.5 – 11.0) 0.0099*
Length 2.4 (0.7 – 4.1) 0.0058*
Thickness of the outer rim 24.2 (4.6 – 43.8) 0.0153*
CI confidence interval
* P <0.05, statistical significance
Table 3 Specific ultrasound features as predictors of the necessity of
surgery
Ultrasound
feature (cm)
Sensitivity Specificity Positive
predictive value
Negative
predictive value
Diameter ≥2.1 100 82.1 70.8 100
Length ≥4.2 94.1 84.6 72.7 97.1
Thickness ≥0.4 88.2 84.6 71.4 94.3
1038 Langenbecks Arch Surg (2011) 396:1035–1040
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application of ultrasound technology, the presence of
temporary or transient small bowel intussusceptions has
become clinically apparent [1, 4, 5, 8, 11]. Doi et al. [8]
have suggested the term benign small bowel intussuscep-
tion to describe those that are found incidentally and/or
resolve spontaneously. Reports have suggested that 50%
or more of SBIs will resolve spontaneously [1, 8, 12], thus
identifying those that will resolve with conservativemanagement, and those that require surgical management
is of clinical importance. Delay of surgery can result in
intestinal necrosis, and surgical management of an SBI
that is likely to resolve spontaneously exposes the patient
to the risks of surgery [2]. While the findings of this study
indicated that a large percentage of SBIs resolved
spontaneously, we are confident of the results as the
diagnosis of SBI was confirmed by two experienced
physicians in each case.
Kim [4] reviewed the ultrasound findings of 34 SBIs
diagnosed in 32 infants and children and found that
transient SBIs typically exhibited a small size (meandiameter 1.5 cm) without wall swelling, a short segment
(mean length 1.8 cm), preserved wall motion, and the
absence of a lead point. Mateen et al. [11] reviewed the
records of 108 consecutive patients (adults and children)
with intestinal intussusceptions, of which 41 were diag-
nosed as transient SBIs. They found that SBIs without an
identifiable pathological lead point, normal wall thickness,
normal non-dilated proximal bowel, normal vascularity on
color Doppler ultrasound, and a length of <3.5 cm reduced
spontaneously and were not of clinical significance. On the
other hand, Munden et al. [1], in a study of 35 cases of
SBIs in adults and children, found that a length >3.5 cm
was a strong indicator for the need of surgical intervention.
Possible reasons for the difference between the results of
Munden et al. and those of the current study are ethnic
differences in the subjects of the two studies, differences in
the ultrasound equipment used, and differences in the
statistical methods used.
The presence of a pathological lead point is suggestive
of the need for surgical intervention. Koh et al. [3] reported
the characteristics of six patients with SBIs who required
surgical intervention, and five exhibited a pathological lead
point on ultrasound. Ko et al. [2] reported the presence of
pathological lead points in 8 of 19 surgically proven cases
of SBIs in pediatric patients. Navarro et al. [13] found that
surgery was required in 32 of 43 children with intussus-
ceptions with pathological lead points. Interestingly, a
pathological lead point was not identified in any of the
patients, surgical or non-surgical, in our study.
In the surgical group, ultrasound-guided hydrostatic
reduction using a saline enema was attempted in five cases,
and failed in four cases. In one case, recurrence occurred
after successful reduction, and surgical treatment was
carried out. Mirilas et al. [14] studied the sonographic
features that correlated with hydrostatic reducibility of
intestinal intussusceptions in infants and children. They
found that when the head of the intussusception appeared as
a target-like mass, the hydrostatic reduction rate was 100%.
When the head appeared as a donut-like mass, hydrostatic
reproducibility depended on the thickness of the hypo-
echoic external ring of the donut, with larger thicknessescorrelating with failure of hydrostatic reduction and the
need for surgery. In addition, when a small amount of fluid
was present within the head of the intussusception,
hydrostatic reduction was unsuccessful in all cases.
Though ultrasound imaging features are useful for
determining the necessity of surgical intervention, the
need for surgical intervention also depends on clinical
signs and symptoms that may suggest intestinal obstruc-
tion or ischemia. Our results suggest that if the patient
has no signs of mechanical ileus, the length of intussus-
ception is short (<4.2 cm), the diameter of intussuscep-
tion is small (<2.1 cm), and there is no swelling of theintestinal wall, it should be considered a transient SBI,
and close observation and repeat ultrasounds are war-
ranted. Conversely, if the length of intussusception is
≥4.2 cm, the diameter of intussusception is ≥2.1 cm, the
thickness of the outer rim is ≥0.4 cm, there is swelling of
the bowel wall, and there is evidence of mechanical ileus
(e.g., vomiting, abdominal distension), surgical manage-
ment should be considered.
There are some limitations to the current study that should
be considered. This was a retrospective study with a relatively
small number of cases performed at one center. A larger
number of cases are necessary to confirm the findings. Enema
reduction was not attempted primarily in all of the 17 cases
that were managed surgically; although 5 cases once
underwent ultrasound-guided hydrostatic reduction using a
saline enema, all failed. Thus, evaluation of a relationship
between the reducibility of intussusception with non-surgical
methods vs. spontaneous reduction or the need for laparotomy
was not possible. Lastly, unavoidable error in ultrasound
measurements may potentially affect the results.
Conclusion
In summary, our data indicate that an intussusception
diameter ≥2.1 cm, length ≥4.2 cm, and thickness of the
outer rim ≥0.40 cm predict the need for surgical manage-
ment in pediatric patients with SBIs. These values may be
of assistance to clinicians when determining if surgery is
required in pediatric patients with SBIs. Values below those
determined from these data should be interpreted with
caution in patients with signs and symptoms of mechanical
ileus or intestinal ischemia.
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Acknowledgments This work was financially supported by Shengjing
Outstanding Scientific Foundation (grant no. m850) from The Shengjing
Hospital of China Medical University.
Conflicts of interest None.
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