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Walailak Chaiyasoot, M.D.*, Nunn Jaruthien, M.D.**
*Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ailand, **Department of Radiology, Ramathibodi
Chakri Naruebodindra Hospital, Mahidol University, Bangkok, ailand.
Outcomes of Percutaneous Drainage vs. Antibiotic
Therapy Alone or Emergency Surgery in
Periappendiceal Abscess
ABSTRACT
Objective: To compare the treatment outcomes in patients with periappendiceal abscess who underwent percutaneous
drainage, antibiotics therapy alone, or emergency surgery in a single hospital.
Methods: From January, 2013 to December, 2018, a retrospective cohort study was done in 124 patients who were
diagnosed as periappendiceal abscess or phlegmon by CT scan in Siriraj Hospital, Bangkok. We evaluated patients’
demographics, the abscess characteristics, and the outcomes of treatment including one of the three therapeutic
options: image-guided percutaneous drainage, antibiotics alone, or emergency surgery.
Results: Among 124 patients, 44 (35.5%) underwent percutaneous drainage, 57 (46.0%) were treated with antibiotics
alone, and 23 (18.5%) underwent emergency surgery. e percentages of patients with successful outcomes were
84.1% in percutaneous drainage, 98.2% in antibiotics treatment alone, and 95.7% in surgery. Antibiotics treatment
alone was signicantly associated with more successful outcome, with odds ratio (OR) of 9.882 (95% CI 1.162-
84.066; P value 0.036), as compared with percutaneous drainage, while surgery showed no signicant dierence.
e length of stay in the percutaneous drainage group (median of 10 days, minimum or maximum of 3 or 67 days)
was signicantly longer than the antibiotics group (median of 6 days, minimum or maximum of 1 and 53 days)
with a P value of 0.008.
Conclusion: e antibiotics treatment alone was signicantly associated with more successful outcome and shorter
hospital stay than percutaneous drainage in patients with a periappendiceal abscess or a phlegmon. We suggest
percutaneous drainage in the patients with larger sized abscess and show no improvement aer antibiotics treatment.
Keywords: periappendiceal abscess; phlegmon; percutaneous drainage (Siriraj Med J 2021; 73: 10-16)
Corresponding author: Walailak Chaiyasoot
E-mail: wchaiyasoot@gmail.com
ORCID ID: http://orcid.org/0000-0003-2892-4064
Received 13 August 2020 Revised 25 September 2020 Accepted 26 September 2020
http://dx.doi.org/10.33192/Smj.2021.02
INTRODUCTION
Perforated appendicitis resulting in periappendiceal
abscess occurs approximately 20% in patients with acute
appendicitis and oen causes morbidity.
1
A contrast-
enhanced computed tomography (CT) scan is a diagnostic
tool that can evaluate the feasibility of percutaneous abscess
drainage and can guide the access route of drainage,
either transabdominal or transgluteal approach.
2
ere is no denite treatment guideline for these
group of patients, either conservative management
(antibiotic therapy alone or antibiotics combined with
percutaneous drainage) or emergency surgery.
3
Chaiyasoot et al.
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Percutaneous drainage with intravenous (IV) antibiotics
in periappendiceal abscess is an eective and minimally
invasive treatment.
4-9
However, some patients develop
complications aer percutaneous drainage leading to
prolonged hospitalization or emergency appendectomy.
An algorithm for the management of periappendiceal
abscesses indicated that, if there is diuse peritonitis, the
patient should undergo immediate surgery. But if there
is no peritonitis, the feasibility of percutaneous drainage
should determine the management.
2
Objectives
e purpose of this study was to compare the outcomes
of patients with periappendiceal abscess or phlegmon
who were treated by percutaneous drainage, antibiotics
alone or emergency surgery, in our university hospital.
MATERIALS AND METHODS
Patient selection
e study protocol was approved by the Institutional
Review Board (IRB) of Siriraj Hospital, Mahidol University
(Si 423/2019). We retrospectively analyzed all patients
who were diagnosed as periappendiceal abscess based
on CT ndings and conrmed by the patients’ discharge
summary from January, 2013 to December, 2018. ose
patients underwent one of these three treatment options:
ultrasound (US) or CT-guided percutaneous drainage,
IV and oral antibiotics therapy alone, or surgery. e
treatment choice was judged individually by the referring
physicians based on the patients’ imaging ndings. All
patients had been treated with antibiotics before and aer
drainage/surgery until complete course. e patients were
classied as percutaneous drainage group if drainage was
done within three days aer the diagnosis, as recommended
by Richmond.
2
e feasibility of drainage was decided
by on-call interventional radiologists.
Among a total of 137 patients whose CT showed
periappendiceal abscess or phlegmon, ten patients were
excluded due to being transferred to other hospitals.
ree were excluded because their nal pathological
diagnoses resulted in appendiceal or cecal tumor. e
remaining 124 patients were included in our study.
Preprocedure CT
A diagnostic CT scan (120 kVp; 300 mA; section
thickness, 1.25 mm; pitch, 1.735:1) was conducted on a
64-slice CT scanner (GE Light speed VCT), (GE Discovery),
and a 256-MDCT (GE revolution CT). Intravenous
contrast-enhanced CT (non-ionic iodinate contrast
media 350 mg I/ml) was performed with a dose of 2 ml/kg.
and an injection rate of 3 ml/second.
Data collection
e demographic data, abscess characteristics, time
interval between percutaneous drainage and surgery,
and type of surgical procedures were all recorded.
A periappendiceal abscess is dened as a uid collection
adjacent to the appendix, which has an attenuation of
0-20 Hounseld units (HU) on CT scan. A phlegmon is
dened as an area measuring 20 HU or greater within
the periappendiceal fat.
We graded abscess based on Jerey, et al.’s classication
system.
10
Grade 1 is dened as periappendiceal phlegmon
or abscess smaller than or equal to 3 cm. Grade 2 is a
well-circumscribed periappendiceal abscess larger than
3 cm. Grade 3 is a large, poorly dened periappendiceal
abscess extending to a distant location (pelvic cavity or
interloop spaces) and multiple abscesses.
Percutaneous drainage procedures were performed
by four experienced interventional radiologists. e details
of each procedure are shown in Table 1. e sizes of the
catheter (SKATER
TM
Drainage System, ARGON Medical
Devices, Athens) were between 8-12 Fr, depending on
the viscosity of the aspirated uid. Almost all access
routes were transabdominal (Fig 1); only one patient
had transgluteal route.
TABLE 1. e detail of percutaneous abscess drainage
procedures.
Variables n = 44
Image guidance
CT guided 8 (18.2%)
US guided 11 (25.0%)
CT and US guided 25 (56.8%)
Technical approach
Transabdominal 43 (97.7%)
Transgluteal 1 (2.3%)
Catheter size (Fr)
8 Fr 12 (27.3%)
10 Fr 26 (59.1%)
12 Fr 6 (13.6%)
Data are expressed as number (percentage)
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Chaiyasoot et al.
A successful outcome for percutaneous drainage is
dened as the patient recovering aer a single drainage
by decreasing fluid output (less than 10 ml/day x 3
consecutive days), with a follow-up CT and/or US
showing a decreasing size of the abscess, and the patient
being discharged from the hospital without surgery.
Percutaneous drainage failure is dened when clinical
worsening aer drainage and need urgent surgery. e
patients who later had elective surgery were not classied
as percutaneous drainage failure. A successful outcome
for antibiotics treatment is dened as the patient’s clinical
improvement and/or follow-up imaging shows abscess
resolution, and the patient being discharged aer IV
antibiotics given for seven days.
2
A failed outcome for
antibiotic treatment alone are a clinically worsening aer
treatment and need further percutaneous drainage or
urgent surgery. A successful outcome for surgery is dened
as patient recovery aer a surgery and can be discharged
from the hospital. Aer the rst surgical procedure, if a
patient required re-admission for antibiotics treatment,
percutaneous drainage, or re-surgery, it is dened as
surgical failure outcome.
The antibiotic protocols in our hospital were
Ceriaxone, 2 grams IV OD, with Metronidazole; 500
milligrams IV q 8 hours; or Piperacillin/ Tazobactam,
4.5 grams IV q 8 hours for 5-7 days. In the percutaneous
drainage group and the surgery group, IV antibiotics
were continued aer drainage/surgery until 14 days.
Aer discharge from the hospital, all patients received
oral antibiotics: Cefdinir, 200 milligrams PO q 12 hours,
with Metronidazole, 400 milligrams PO q 8 hours for 7
days.
Statistical analysis
Data were prepared and analyzed using PASW
Statistics 18.0 (SPSS Inc., Chicago IL USA). Patients’
clinical characteristics were summarized as median
(minimum, maximum) for quantitative variables, while
numbers and percentages were summarized for qualitative
variables. e Mann-Whitney U test was used to compare
quantitative variables between the successful and failed
groups. e Pearson Chi-square test or Fisher’s Exact test
was used to compare the qualitative variables between the
groups. Backward conditional-binary logistic regression
was used to adjust any confounding variables between
the treatment and the outcome.
RESULTS
Among 124 patients, 68 were male (54.8%) and
56 were female (45.2%), with a mean age of 53 (a range
from 7-93 years). Symptoms onset until admission was
1-30 days (a mean of 5 days).
We categorized the patients into three groups
according to the treatment options: 44 people (35.5%)
underwent percutaneous drainage; 57 (46.0%) were
treated with antibiotics alone, and the remaining 23
patients (18.5%) underwent emergency surgery. e
characteristics of the abscesses in each group are shown in
Table 2. e abscess size was largest in the percutaneous
drainage group (a median size of 6.0 cm.), which had
statistically signicant dierence as compared with the
antibiotics-alone and surgery groups.
For the abscess grade, a Grade 1 abscess was found
least frequently in the percutaneous drainage group,
as compared to the other two groups, with a statistical
Fig 1. Grade 2 abscess in a 58-year-old female with abdominal pain and diarrhea for 1 week.
(A) Contrast CT showed a well-circumscribed periappendiceal abscess, size 6.1x3.5 cm. with internal air bubbles (asterisk) at right lower
abdomen. (B) e patient underwent percutaneous transabdominal drainage of abscess. Follow up CT showed resolution of the abscess.
Note the drainage catheter (arrow)
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TABLE 2. Comparison of patients’ demographics and characteristics of abscess in each treatment option; percutaneous
drainage, antibiotic (ATB) therapy alone and surgery alone.
Variables Percutaneous ATB alone Surgery P-value
drainage (n = 44) (n = 57) (n = 23)
Abscess size (cm) 6.0 (2.5, 12.3) 3.7 (0.9, 12.0) 3.6 (0.9, 11.0) <0.001
Abscess grade
Grade 1 2 (4.5%) 17 (29.8%) 6 (26.1%) 0.005
a,b
Grade 2 29 (65.9%) 35 (61.4%) 14 (60.9%) 0.875
Grade 3 13 (29.5%) 5 (8.8%) 3 (13.0%) 0.019
a
Number of abscess 0.173
Single 35 (79.5%) 52 (91.2%) 18 (78.3%)
Multiple 9 (20.5%) 5 (8.8%) 5 (21.7%)
Phlegmon 0 (0.0%) 21 (36.8%) 1 (4.3%) <0.001
Abscess location 0.021
Right lower quadrant 32 (72.7%) 53 (93.0%) 18 (78.3%)
Extend to distant location 12 (27.3%) 4 (7.0%) 5 (21.7%)
Extraluminal air 27 (56.2%) 10 (20.8%) 11 (22.9%) <0.001
Appendicolith 7 (28.0%) 9 (36.0%) 9 (36.0%) 0.043
Small bowel obstruction 2 (40.0%) 1 (20.0%) 2 (40.0%) 0.352
Length of stay (days) 10 (3, 67) 6 (1, 53) 6 (2, 16) 0.008
Recurrent appendicitis 1 (2.3%) 3 (5.3%) 0 (0.0%) 0.438
Data are expressed as number (percentage), median (minimum, maximum)
a
=Percutaneous drainage and ATB alone,
b
=Percutaneous drainage and surgery
dierence (P value 0.005). A Grade 2 abscess was found
most frequently in every group, with no statistically
signicant dierences (P value 0.875). A Grade 3 abscess
was signicantly found much more in the percutaneous
drainage group than in the antibiotics-alone group (P value
0.019). e number of abscesses was single more than
multiple in every group, with no signicant dierence.
Phlegmon was found most frequently in the antibiotics-
alone group. e length of stay for the percutaneous
drainage group was signicantly longer than for the
antibiotics and surgical group.
e successful and failed outcomes for each treatment
modality are summarized in Table 3. One patient who failed
antibiotics treatment alone underwent appendectomy 15
days later. Another patient had a 6-cm intra-abdominal
collection post-surgery but was successfully treated with
antibiotics. Aer adjusting the confounding variables
(abscess grade, location, phlegmon, extraluminal air,
appendicolith, and length of stay), the results showed
that the antibiotics-alone group had a signicantly more
successful outcome, with an OR of 9.882 (95% CI 1.162-
84.066; P value 0.036) while the surgery group had no
signicance, with an OR of 4.529 (95% CI 0.521-39.386;
P value 0.171), as compared with the percutaneous
drainage group.
Total of 124 patients, 65 (52.4%) had an imaging
follow-up either CT and/or US and 59 (47.6%) had no
imaging follow-up. For the antibiotics-alone group,
26/57 (45.6%) had CT and/or US follow-up. For the
percutaneous drainage group, 36/44 (81.8%) had CT
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Chaiyasoot et al.
and/or US follow-up before the catheter removal. For
the surgical group, 5/23 (21.7%) had CT and/or US
follow-up. Table 4 shows the outcomes aer percutaneous
drainage, indications and types of surgery. e majority
of patients with a successful outcome aer percutaneous
drainage did not undergo surgery (31/44, 70.5%), but
6/44 (13.6%) had an interval appendectomy.
DISCUSSION
Perforated acute appendicitis resulting in
periappendiceal abscess can cause major morbidity.
e denite treatment guidelines for this disease remain
controversial. In our study, we divided patients who were
diagnosed as ruptured appendicitis with periappendiceal
abscess or phlegmon into three groups by the treatment
options: percutaneous drainage, antibiotics therapy
alone, or emergency surgery. In a study by Marin, et al.
4
,
percutaneous drainage in patients with perforated acute
appendicitis had high clinical and technical success rates
up to 90% (37 of 41 patients), with no procedure-related
complications. Similar to our study, there was a high
successful outcome in percutaneous drainage treatment,
37 out of 44 patients (84.1%), and 56 out of 57 patients
(98.2%) who were treated by antibiotics alone. Our study
agreed with previous studies that percutaneous drainage
resulted in good treatment outcome ranged from 78.6%
to 100%.
5-8
A meta-analysis by Anderson and Petzold
9
found
that antibiotics treatment alone for periappendiceal
abscess had a successful outcome in 93% of the cases,
and percutaneous drainage was needed for only 20%.
Furthermore, a study by Miaroski et al.
11
found only
TABLE 3. Outcome within treatment options.
TABLE 4. Outcomes aer percutaneous drainage.
Choice Successful outcome Failure outcome
Percutaneous drainage (n = 44) 37 (84.1%) 7 (15.9%)
Antibiotics alone (n = 57) 56 (98.2%) 1 (1.8%)
Surgery (n = 23) 22 (95.7%) 1 (4.3%)
Outcome n = 44
Successful outcome 37 (84.1%)
Failure outcome 7 (15.9%)
Time from drainage to surgery (days) 42 (2-298)
Indications and types of surgery
Interval appendectomy 6 (13.6%)
Exploratory laparotomy with drainage (Failed drainage) 3 (6.8%)
Hemicolectomy (Failed drainage) 4 (9.1%)
Surgery not done 31 (70.5%)
Data are expressed as number (percentage), median (minimum, maximum)
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1 out of 15 patients (7%) who had initially successful
treatment via combining antibiotics and CT-guided
drainage for a perityphlitic appendiceal abscess had
recurrent appendicitis. Similar to our study, the risk of
recurrent appendicitis was very low as 1 out of 44 patients
(2.3%) in the percutaneous drainage group and 3 out
of 57 (5.3%) in the antibiotics-alone group, but with no
statistical signicance (P value, 0.438).
e purpose of our study was to retrospectively
compare the outcomes of treatment in patients with
periappendiceal abscess or phlegmon who underwent:
percutaneous drainage, antibiotics therapy alone, or
emergency surgery. Until recently, studies have mostly
compared the treatment outcomes between two groups:
immediate surgery and non-surgical treatment.
3,7,12
ose
studies revealed a better outcome for the conservatively
treated group, with a lower incidence of complications.
Kim JK, et al.
3
compared the treatment outcomes between
emergency operation and antibiotics groups, with or
without percutaneous drainage. ey showed a good
outcome (91.7%) for the conservatively treated group.
e only prospective, randomized, controlled trial study
that compared the outcomes between percutaneous
drainage group and antibiotics-only group was by Zerem
et al.,
13
which included periappendiceal abscesses equal
to or >3 cm in diameter. ose researchers concluded
that percutaneous drainage with antibiotics treatment
was more ecient than antibiotics alone because an
appendectomy was less performed in the combined
antibiotics and percutaneous drainage group than in
the antibiotics-alone group.
In contrast to our study, aer adjusting the confounding
variables (i.e., abscess grade, location, phlegmon, extraluminal
air/ appendicolith, and the length of stay), we found that
antibiotics treatment alone was signicantly associated
with a more successful outcome, with an OR of 9.882
(95% CI 1.162-84.066; P value 0.036), as compared with
the percutaneous drainage group. But surgery showed
no statistical dierence to percutaneous drainage, given
its OR of 4.529 (95% CI 0.521-39.386; P value 0.171). As
compared the successful outcomes among the three groups,
antibiotics treatment alone had a successful outcome of
48.7% (56 out of 115 patients), while the percutaneous
drainage group had a successful outcome of 32.2% (37 out
of 115 patients), and the surgery group had a successful
outcome of 19.1% (22 out of 115 patients). Our result is
dierent from that of Zerem et al.
13
because we included
patients who were diagnosed as phlegmon in 21 out of
57 patients (36.8%) in the antibiotics-alone group, but
none of the patients were diagnosed as phlegmon in the
percutaneous drainage group. Furthermore, patients
with varying sizes of abscesses were included in our
study. We found that the abscess size was largest in the
percutaneous drainage group (median size of 6.0 cm.)
as compare to the antibiotics-alone and surgical groups
which (median size of 3.7 cm. and 3.6 cm. respectively)
with a statistically signicant dierence (P value <0.001).
It means that if the abscess is large (equal to or >6 cm),
the clinician tends to choose percutaneous drainage as
the treatment option rather than giving antibiotic alone
or surgery.
Abscess size and grade are according to each other.
Table 2 shows that a Grade 1 abscess (equal or <3 cm.)
was found least frequently in the percutaneous drainage
group, as compared to the other two groups, with a
statistical dierence. It represents the clinicians’ preferring
antibiotic or surgical treatment in cases of small sized
abscess. In contrast to a Grade 3 abscess (a large abscess
or multiple locations) which was signicantly found
much more in the percutaneous drainage group than in
the antibiotics-alone group. It implies that the clinicians
tend to consult percutaneous drainage in patients with
large sized abscess. Because antibiotics therapy alone may
not be eective to get rid of those abscesses and surgical
technique may be more dicult in multiple abscesses
leading to post-operative recurrence. For a Grade 2
abscess (>3 cm. but localize), which was found equally
in every group, without signicant dierences. So, the
choice of treatment in Grade 2 abscess should depend
on clinical judgement either percutaneous drainage,
antibiotic treatment or surgery.
e study by Zerem et al.
13
found that the length of
hospital stay was signicantly shorter in the percutaneous
drainage group. But we found longer hospital stay in
the percutaneous drainage group (a median of 10 days)
than in the antibiotics group (a median of 6 days), with a
P value of 0.008. is was due to the fact that some patients
with post-percutaneous drainage were hospitalized until
no drainage output or imaging follow-up showed abscess
resolution, then the drainage catheters were removed
before they were discharged.
e limitations in our study are that it’s retrospective
and has a single-center design. e patients’ sample
size in each group was rather small. Our result which
indicated that antibiotics treatment alone was signicantly
associated with more successful outcome as compared
with percutaneous drainage had an OR of 9.882 and very
wide range ofcondence interval (95% CI 1.162-84.066).
Further research with more sample size is needed to make
the results more reliable. Lastly, some of the patients had
an incomplete clinical-data record, and approximately
50% of them did not have imaging follow-up.
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CONCLUSION
e antibiotics treatment alone was signicantly
associated with more successful outcome and shorter
hospital stay than percutaneous drainage in patients with
a periappendiceal abscess or a phlegmon. We suggest
percutaneous drainage in the patients with larger sized
abscess and show no improvement after antibiotics
treatment.
ACKNOWLEDGEMENTS
e authors would like to thank all the interventional
radiologists at the Siriraj Center of Interventional Radiology
for their support. And also thankful Dr. Sasima Tongsai for
assistance in the statistical analysis.
Conict of interest: No potential conict of interest
relevant to this article was reported.
REFERENCES
1. Wenzke DR, Jacobs JE, Balthazar EJ, Wehrl N. Diseases of the
appendix. In: Gore RM, Levine MS, eds. Textbook of Gastrointestinal
Radiology, Vol 1, 4
th
ed. United States: Elsevier, 2015.p. 955-83.
2. Richmond B. e appendix. In: Townsend CM, Evers BM,
Beauchamp RD, Mattox KL. Sabiston, eds. Textbook of Surgery,
20
th
ed. Canada: Elsevier, 2017.p.1296-311.
3. Kim JK, Ryoo S, Oh HK, Kim JS, Shin R, Kyung E, et al.
Management of appendicitis presenting with abscess or mass.
J Korean Soc Coloproctol 2010;26:413-9.
4. Marin D, Ho LM, Barnhart H, Neville AM, White RR, Paulson
EK. Percutaneous abscess drainage in patients with perforated
acute appendicitis: eectiveness, safety, and prediction of
outcome. AJR 2010;194:422-9.
5. Fagenholz PJ, Peev MP, abet A, Michailidou M, Chang Y, Mueller
PR, et al. Abscess due to perforated appendicitis: factors associated
with successful percutaneous drainage. Am J Surg 2016;212:
794-8.
6. Lasson A, Lundagards J, Loren I, Nilsson PE. Appendiceal
abscesses: primary percutaneous drainage and selective interval
appendicectomy. Eur J Surg 2002;168:264-9.
7. Seif HMA, Reyad HA, Korany M, Metwally M, Ahmed AI.
Immediate operation versus percutaneous drainage for treatment
of appendicular abscess. Egypt J Radiol Nucl Med 2015;46:999-
1002.
8. Zhang H, Bai Y, Wang W. Nonoperative management of
appendiceal phlegmon or abscess in children less than 3 years
of age. World J Emerg Surg 2018;13:10.
9. Andersson R, Petzold MG. Nonsurgical treatment of appendiceal
abscess or phlegmon: a systematic review and meta-analysis.
Ann Surg 2007;246:741-8.
10. Jerey RB Jr, Federle MP, Tolentino CS. Periappendiceal
inammatory masses: CT-directed management and clinical
outcome in 70 patients. Radiology 1988;167:13-16.
11. Miaroski A, Kessler U, Monnard E, Egger B. Two-step procedure
for complicated appendicitis with perityphlitic abscess formation.
Swiss Med Wkly 2017;147:w14422.
12. Gavriilidis P, Angelis ND, Katsanos K, Saverio SD. Acute
appendicectomy or conservative treatment for complicated
appendicitis (phlegmon or abscess)? A systematic review by
updated traditional and cumulative meta-analysis. J Clin Med
Res 2019;11:56-64.
13. Zerem E, Salkic N, Imamovic G, Terzic I. Comparison of
therapeutic eectiveness of percutaneous drainage with antibiotics
versus antibiotics alone in the treatment of periappendiceal
abscess: is appendectomy always necessary aer perforation
of appendix? Surg Endosc 2007;21:461-6.
Chaiyasoot et al.
