Therapeutic effectiveness of percutaneous drainage and factors for performing an interval appendectomy in pediatric appendiceal abscess
Xinglong Rd., Sect.
Therapeutic effectiveness of percutaneous drainage and factors for performing an interval appendectomy in pediatric appendiceal abscess
Chih-Cheng Luo 0
Chen-Sheng Huang 0
Ray-Jade Chen 1
0 Division of Pediatric Surgery, Department of Surgery, Wan Fang Medical Center, Taipei Medical University , 111 Xinglong Rd., Sect. 3, 11696 Taipei , Taiwan
1 Department of Surgery, Taipei Medical University Hospital, Taipei Medical University , 252 Wu-Xing Street, Taipei 110 , Taiwan
Background: In this study, we studied the therapeutic effectiveness of percutaneous drainage with antibiotics and the need for an interval appendectomy for treating appendiceal abscess in children with a research-oriented dataset released by the Bureau of National Health Insurance in Taiwan through the Collaboration Center for Health Information Application (CCHIA). Methods: We identified 1225 patients under 18 years of age who had non-surgical treatment for an appendiceal abscess between 2007 and 2012 in a Taiwan CCHIA dataset. The treatment included percutaneous drainage with antibiotics or antibiotics alone. We also analyzed data of patient's baseline characteristics, outcomes of percutaneous drainage, and indicating factors for performing an interval appendectomy. Results: Totally, 6190 children had an appendiceal abscess, an 1225 patients received non-operative treatment. Of 1225 patients, 150 patients received treatment with percutaneous drainage and antibiotics, 78 had recurrent appendicitis, 185 went on to receive an interval appendectomy, and 10 had postoperative complications after the interval appendectomy. We found that patients treated with percutaneous drainage and antibiotics had a significantly lower rate of recurrent appendicitis (p < 0.05), a significantly smaller chance of receiving an interval appendectomy (p < 0.05), and significantly fewer postoperative complications after the interval appendectomy (p < 0.05) than those without percutaneous drainage treatment. Older children (13 ~ 18 years) patients were found to have a significantly smaller need to receive an interval appendectomy than those who were ≤ 6 years of age (odd ratio (OR) = 2.071, 95 % confidence interval (CI) = 1.34-3.19, p < 0.01), and those who were 7 ~ 12 years old (OR = 1. 662, 95 % CI = 1.15-2.41, p < 0.01). In addition, those treated with percutaneous drainage were significantly less indicated to receive an interval appendectomy later (OR = 2.249, 95 % CI = 1.19 ~ 4.26, p < 0.05). In addition, those with recurrent appendicitis had a significantly increased incidence of receiving an interval appendectomy later (OR = 3.231, 95 % CI = 1.95 ~ 5.35, p < 0.001). (Continued on next page) © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
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Conclusions: In this study, we used nationwide data to demonstrate therapeutic effectiveness of percutaneous
drainage and antibiotics was more beneficial than only antibiotics in treating patients with an appendiceal abscess.
We also found three factors that were significantly associated with receiving an interval appendectomy: recurrent
appendicitis, being aged ≤ 13 years, and treatment with antibiotics only.
Appendicitis is a common pediatric surgical emergency.
Even with the use of ultrasonagraphy and computed
tomography (CT), perforation rates in children have
been reported to be 30 % over the last 30 years, and
some perforated patients presented themselves with an
appendiceal abscess [1–3].
Appendiceal abscess can immediately be treated by
surgery or by non-surgical management, consisting of
treatment with parenteral antibiotics alone, or treatment with
antibiotics and ultrasound- or CT-guided drainage,
followed by an interval appendectomy [4, 5]. But the need
for a future interval appendectomy remains debatable [6–
10]. Without an interval appendectomy, the risks of
recurrent appendicitis and missed pathological findings are
uncertain. The recurrence rate after treatment with
percutaneous drainage and antibiotics for patients with an
appendiceal abscess was found to be low, and an interval
appendectomy in most cases was not required [11, 12].
In this study, we used dataset from Taiwan’s National
Health Insurance (NHI) to analyze the effectiveness of
percutaneous drainage therapy, and to determine the
possible indicating factors for performing an interval
This study used data from the Taiwan National Health
Insurance (NHI) program, which the government initiated
in 1995, and which covers 99 % of the population of 23
million people. The Bureau of the NHI (BNHI) in Taiwan
has released a research-oriented database through the
Collaboration Center for Health Information Application
(CCHIA). In 1999, the BNHI began to release all claims
data in electronic form, to allow researchers to trace
almost all uses of medical services for all people in Taiwan,
including all children with appendicitis.
We extracted datasets between 2007 and 2012 from
the NHI research database (NHIRD) released by the
BNHI through the CCHIA. The study protocol was
approved by the Taipei Medical University Joint
Institutional Review Board without the need to obtain
signatures of study participants, because the NHIRD
consists of de-linked secondary data.
We enrolled 1225 pediatric patients (≤18 years of age)
with a diagnosis of an appendiceal abscess who received
non-surgical treatment between January 2007 and
December 2012, because the International Classification of
Disease, Ninth Revision, Clinical Modification
(ICD-9CM) codes were available since 2007.
Inpatient claims, which included records of all
hospitalizations, provided a substantial amount of
information. We linked study participants to the inpatient
claims data to identify appendiceal abscess (540.9),
percutaneous drainage (470.22C) and postoperative
complications include an intra-abdominal abscess (IAA,998.59)
and postoperative bowel obstruction (PBO,560.81 or
997.4) based on ICD-9-CM codes.
Patients were divided into three age groups: ≤ 6, 7 ~ 12,
and 13 ~ 18 years old. The definition of an interval
appendectomy is a patient who had initial medical therapy
with intravenous antibiotics or possibly drainage followed
by an elective appendectomy. The definition of recurrent
appendicitis is a patient who has appendicitis again after
initial non-surgical treatment without an appendectomy.
Excluded from the study were patients for whom the
initial non-surgical treatment failed or who had recurrent
appendicitis and received immediate surgery.
We performed a univariate analysis between different
age group and treatment methods. We present
continuous variables as the mean ± standard deviation (SD) and
analyzed differences in these parametric variables
between groups with Student’s t-test. We also present
categorical variables as ratios, and analyzed differences
in non-parametric variables between groups with
Chisquare test. A multivariate logistic regression analysis
was used to identify independent factors including
factors of different age groups, gender, the use of
antibiotics, the use of percutaneous drainage, and recurrent or
non-recurrent appendicitis. The relationship between
potential variables and the necessity for an interval
appendectomy was assessed by odds ratios (ORs) and
related 95 % confidence intervals (CIs).
We used the Statistical Analytic System software
version 9.3 (SAS Institute, Cary, NC, USA) to analyze the
data in this study. Differences between groups were
considered significant if p values were < 0.05.
Table 2 Comparison of therapeutic effectiveness in patients
with and without percutaneous drainage
Without drainage (%)
Totally, 6190 children had an appendiceal abscess, and
non-surgical treatment was used in 1,225 patients.
Table 1 lists of demographic data of all patients with an
appendiceal abscess. Of 1225 patients, 185 received an
interval appendectomy, 78 had recurrent appendicitis,
and 10 had postoperative complications after an interval
Of the 1225 children presenting with an appendiceal
abscess had non-surgical treatment. 150 (2.2 %) patients
were treated by percutaneous drainage with antibiotics,
and the remaining 1075 (97.8 %) were only given
antibiotics without percutaneous drainage. The average time
of hospital stay for patients treated with percutaneous
drainage (at 12.8 ± 8.9 days) was longer than that
without drainage (9.7 ± 6.4 days) (p < 0.05). Table 2
demonstrates that patients treated with percutaneous drainage
and antibiotics had significantly lower rates of recurrent
appendicitis (p < 0.05), a significantly smaller chance of
receiving an interval appendectomy (p < 0.05), and a
significantly smaller chance of postoperative complications
(p < 0.05) after an interval appendectomy than those
without percutaneous drainage treatment.
In our study (Table 1), 185 (15.1 %) patients received
an interval appendectomy and the remaining 1040
(84.9 %) did not. Data from the multivariate logistic
regression analyses (Table 3) showed that pediatric
patients who received percutaneous drainage had a
significantly smaller need to receive an interval
appendectomy (OR = 2.249, 95 % CI = 1.187 ~ 4.260, p < 0.05),
older (13 ~ 18 years) patients had a significantly smaller
need to receive an interval appendectomy than those
who were ≤ 6 years, (OR = 2.071, 95 % CI = 1.34 ~ 3.19,
p < 0.01), and those who were 7–12 years old (OR =
1.662, 95 % CI = 1.15 ~ 2.41, p < 0.01), and patients with
recurrent appendicitis were significantly likely to have an
Table 1 Demographic data of appendiceal abscess patients
a Percentage who received non-operative treatment
Interval appendectomy (IA)
Postoperative complications after IA
a Significantly greater therapeutic effectiveness in patients with drainage
compared with those without drainage (p < 0.05)
increased incidence of receiving an interval
appendectomy (OR = 3.231, 95 % CI = 1.95 ~ 5.35, p < 0.001).
To the best of our knowledge, this is the first study to
use a large nationwide database to study the
effectiveness of percutaneous drainage therapy, and to determine
the indicating factors for receiving an interval
appendectomy in patients with appendiceal abscess.
Some recent reports mentioned that treatment of
acute appendicitis with abscess formation or phlegmon
with non-surgical management in children followed by
an elective appendectomy has become well-recognized
and accepted [13–15]. Non-surgical treatment of a
pediatric appendiceal abscess is now also an acceptable
approach in Taiwan. As shown in Table 1, 19.8 % of
patients with appendiceal abscess received non-surgical
treatment, consisting of parenteral antibiotics alone and
ultrasound- or CT-guided drainage, followed by an
interval appendectomy [4, 5]. We found that 12.2 % of
patients received treatment with percutaneous drainage
and antibiotics, but another 87.8 % of them received
only antibiotics. Older children (13 ~ 18 years of age)
Table 3 Multivariate logistic regression of indicating factors for
performing an interval appendectomy
95 % Confidence interval
*p < 0.05, **p < 0.01, ***p < 0.001
had an increased incidence of receiving percutaneous
drainage in our study. In our opinion, the reason may
have been that the technique of drainage is more easily
to be performed in older children who are physically
Previous reports revealed that percutaneous drainage
with the use of antibiotics is more efficient than treatment
with antibiotics alone to successfully and completely treat
appendiceal abscess without an interval appendectomy
[11, 12]. We had the same findings (Table 2), showing that
patients treated with percutaneous drainage and
antibiotics had a significantly not only decreased rate of
receiving an interval appendectomy (p < 0.05), but also had a
significantly lower rate of recurrent appendicitis (p < 0.05)
and had a significantly smaller chance of having
postoperative complications (p < 0.05) after an interval
appendectomy. The average time of hospital stay (12.8 ± 8.9 days)
was longer for patients treated with percutaneous drainage
than those without drainage (9.7 ± 6.4 days) but with
antibiotics alone (p < 0.05). Based on these data, we suggest
that the therapeutic effectiveness of percutaneous drainage
may be due to patients’ hospitalization until drainage was
There are few reports dealing with indicating factors
for performing an interval appendectomy. The presence
of an appendicolith, increased blood C-reactive protein
levels, elevated percent bands of white blood cells, and
partial small bowel obstruction on admission are
reported to be associated with an increased risk of
recurrent appendicitis, and thus, such patients should receive
an interval appendectomy [16–18]. In the multivariate
logistic regression analyses from our national database
(Table 3), we found that pediatric patients had a
significantly smaller need to receive an interval appendectomy
later on if they had received percutaneous drainage (OR
= 2.249, p < 0.05) and were significantly older (13 ~
18 years) (p < 0.01). But if the pediatric patients had
recurrent appendicitis, they had a significantly greater
need to receive an interval appendectomy (OR = 3.231,
p < 0.001).
Readers are warned against over-interpreting our study
data because it has two major limitations. First, with a
population-based database, we had no other available
clinical data including patients’ descriptions of clinical
presentation, laboratory data, severity of appendiceal
abscess, or pathologic confirmation of an appendiceal
abscess. Second, we were unsure whether the staff surgeon
decided to treat patients with non-surgical treatment,
the use of percutaneous drainage, and performing an
In this our study, we used nationwide data in Taiwan to
demonstrate that the therapeutic effectiveness of
percutaneous drainage and antibiotics was more beneficial
than antibiotics alone in treating patients with
appendiceal abscess. We also found three factors significantly
associated with receiving an interval appendectomy:
recurrent appendicitis, being aged less than 13 years,
and treatment with antibiotics only.
Winston W. Shen gave constructive editing comments on the manuscript.
Availability of data and materials
The data that support the findings of this data are available from [the
Collaboration Center for Health Information Application (CCHIA)] but
restrictions apply to the availability of these data, which were used under
license which you must apply previously and be accepted for the current
study, so are not publicly available. Data are however available from the
authors upon reasonable request and with permission of [CCHIA].
L-CC (first author and correspond author) : contributed to conception and
design the research, and had been involved in drafting the manuscript. C-KF
(co-first author) : did analysis and interpretation of data, and was involved in
drafting the manuscript. H-CS: investigated and resolved the questions related
to the accuracy of the data within manuscript. L-HC : also help investigate and
resolve the questions related to the accuracy of the data within manuscript.
S-MW: was involved in drafting the manuscript. H-HC: revised important
intellectual content of the manuscript. C-WK : had most acquisition of data, and
analysis and interpretation of data. C-RJ (co-correspond author) : contributed to
conception and design of the research and gave final approval of the version
to be published. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Consent for publication
“Not applicable” in this section.
Ethics approval and consent to the participate
The study was approved by the TMU-Joint Institutional Review Board
without the need of obtaining signature of study participants, reference
number is 201404074.
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