Keywords
systematic review - meta-analysis - perianal abscess - children - primary fistula
treatment
Introduction
A perianal abscess (PA) is an acute inflammatory condition mainly characterized by
a collection of pus.[1] It has been previously reported that only a small proportion of patients are children.[2]
[3]
[4] In recent years, an increasing amount of evidence suggests that these diseases are
no longer considered rare conditions in childhood. Patients are often accompanied
by acute and severe pain originating from erythema, swelling, induration, and fluctuance
in the anal area, whereas disseminated systemic infection or sepsis are unusual.[5] Fistula-in-ano (FIA) is an epithelialized connection between perianal skin and the
anorectal canal, which represents chronic manifestation developed from the PA. It
is widely accepted that abscesses arise from the obstruction of anal glands.[6] Additionally, several predisposing disorders may also be responsible for the development
of an abscess, such as inflammatory bowel disease (IBD), anorectal malformations,
and immunodeficiency.[7]
[8]
With a clear predominance of males, most children have the onset of PA in the first
year of life.[9]
[10] Various therapies have been applied, while decision-making on choosing the treatment
depends on the experiences and judgments provided by physicians, as well as the tendency
of caregivers. Nonoperative management will be more acceptable due to its safety and
efficacy, while prompt incision and drainage (I&D) still should be implemented for
abscesses with significant fluctuation, which provoke pain or systemic signs of sepsis
and cannot discharge spontaneously.[11]
[12] Yet, the rate of fistula formation after this initial management among studies was
reported to be around 10 to 30%.[10]
[13]
[14]
[15]
Some surgeons suggest that I&D with primary fistula treatment (I&DF) can reduce the
possibility of recurrence and progression to FIA. However, such a procedure may also
be associated with a risk of fecal incontinence or transient manometric reduction
in anal sphincter pressures in previous meta-analyses on adults.[16]
[17] For children, it is also affiliated with concerns about the safety of anesthesia
exposure.[18] This controversial topic has not been deeply explored so far in this special population.
Our preliminary searches revealed that there were few randomized controlled trials
(RCTs) focusing on this issue, and all of the relevant studies were from China which
might cause a potential source of bias and addressed the review question incompletely
in children.[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26] According to the Cochrane Handbook for Systematic Reviews of Intervention, we decided
to consider nonrandomized studies (NRSs) for objectively evaluating the benefits and
harms of these two surgical interventions among the pediatric population.[27] Thereby, an extensive search of the literature was conducted to reduce the possibility
of publication bias. The aim of this systematic review and meta-analysis which compare
outcomes after I&DF and I&D was to determine the role of primary fistula treatment
in efficacy and complications.
Methods
This systematic review and meta-analysis were registered with the number CRD42022331529
(https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022331529).
Criteria Used to Consider Studies for This Review
Type of studies: Nonrandomized clinical trials from 1992 through July 2022 which compared outcomes
after I&DF and I&D for PAs in children were included. Published articles in any available
language were considered. Nonclinical trials, clinical trials with no control, or
RCTs were excluded.
Type of participants: Children (< 18 years old) undergoing surgical drainage of PAs without the diagnosis
of IBD, anorectal malformations, Hirschsprung's disease, tuberculosis, malignancy,
and immunosuppressive disorders.
Type of interventions: Two types of interventions studied were compared with each other:
Treatment group (I&DF): I&DF, which was comprised of fistulotomy, fistulectomy, and
use of cutting setons, as well as addressing the offending crypt and identifying an
internal opening.
Control group (I&D): I&D alone.
Search Methods for Study Identification
The following international databases were searched: PubMed, Embase, Cochrane Central
Register of Controlled Trials (CENTRAL), Scopus, and Web of Science. In addition,
the Chinese databases were also searched, including China National Knowledge Infrastructure
(CNKI), VIP, Wanfang Data, Sinomed, and Yiigle.
To achieve comprehensive search results relevant to the study topic, there was no
restriction on the study type. Three of the authors (Y.S., S.H., and X.Z.) conducted
the systematic literature search, using a combination of the following terms: “anal,”
“abscess,” “child,” and “drainage.” Correlative subject headings, free words, synonyms,
along with wildcards were used to expand the retrieval scope. The search strategy
used to search PubMed is shown in [Supplementary Table S1]. The search strategies were modified to adapt different electronic databases.
All duplications were precluded through identification in Endnote. Articles, as follows,
were also kept out through title/abstract screening by two authors (Y.S. and X.Z.)
independently: (1) irrelevant to the study topic, (2) patients with other underlying
diseases, which had been listed above, (3) a review or meta-analysis, (4) a case report
or meeting abstract, and (5) an in vitro study or animal experiment. The secondary
screening was based on a full-text assessment to determine whether studies met the
inclusion criteria. Studies without sufficient information were also excluded from
the meta-analysis. In case of disagreement, a third reviewer (S.H.) was involved to
reach a consensus. The selection process was performed according to the Preferred
Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement.[28]
Data Extraction and Selection
Three authors independently (Y.S., S.H., and X.Z.) extracted data from each included
study into prepared datasheets. When encountering inconsistencies, we arbitrated through
discussion with the corresponding author (C.W.). The first primary outcome was the
healing rate defined as the complete healing of the fistula after the operation by
clinical assessment. Another primary outcome was the fistula formation rate during
the follow-up period. The secondary outcomes were fecal incontinence and wound healing
duration, which represented the number of days taken for complete closure of the wound.
Other variables about characteristics and treatment details of included NRSs were
also collected. Any data missing or unavailable in the published articles were marked
as not reported (NR).
Risk of Bias Assessment
The Newcastle-Ottawa Scale was used to assess the quality of included cohort NRSs
by two authors separately (S.H. and X.Z.). The final results were determined by discussing
with two other authors (Y.S. and C.W.). Each study, which can be awarded from 0 to
9 stars, was evaluated from three broad perspectives using the above-mentioned method.
A higher score indicated a high quality of the selected article. The study quality
can be classified into three grades: low (scores < 5), moderate (5 ≤ scores < 8),
and high (8 ≤ scores ≤ 9). The final score of a study, which was equal to or greater
than 5, was selected for further meta-analysis.
Strategy for Data Synthesis
Relevant variables were extracted and saved in a Microsoft Excel datasheet. Results
for dichotomous data are expressed as numbers (proportion), whereas continuous variables
are presented as mean and standard deviation (SD). The meta-analysis was conducted
using Review Manager 5.4.1 software. Pooled odds ratio (OR) with 95% confidence intervals
(CI) was estimated for dichotomous outcomes (healing rate and fistula formation rate),
and mean difference with 95% CI were calculated for continuous outcomes (wound healing
duration). Cochrane Q test and I
2 statistics were used to assess the heterogeneity among studies, which was accepted
when p-value greater than 0.1 and I2
less than 50%. If p-value less than 0.1 or I2
greater than 50%, which suggested a higher probability of inconsistency, the random-effects
model was applied; otherwise, the fixed-effect model was conducted. Publication bias
was assessed through the funnel plot when the number of included studies was more
than 10.
Results
Literature Search
Overall, 3,933 records were retrieved from 10 electronic databases between 1992 and
July 2022. After the exclusion of duplicates, 79 articles were left through primary
screening of the title and abstract. Ultimately, 16 NRSs were eligible for the final
meta-analysis. Eight studies were retrospective,[12]
[29]
[30]
[31]
[32]
[33]
[34]
[35] 7 were prospective,[36]
[37]
[38]
[39]
[40]
[41]
[42] and 1 was NR.[43] Among these, 11 articles were in Chinese, and 5 studies in English were from New
Zealand, Sweden, Australia, the United Kingdom, and China, respectively. A flow diagram
of the search and selection process is shown in [Fig. 1].
Fig. 1 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) diagram
showing search results for meta-analysis.
Study Characteristics
We presented the characteristics of 16 included NRSs in [Table 1]. There were a total of 1,262 patients, including 1,066 males and 196 females. All
participants included in the control group had undergone I&D of PAs, while those in
the treatment group received I&DF. In one study, 108 patients with 111 abscesses were
divided into two groups.[12] Finally, 685 cases were enrolled in the treatment group, and 580 cases were drained
alone. In detail, the majority of patients were managed by drainage with fistulotomy
while cutting setons were selectively employed for PAs with the high location of identified
internal openings.[40]
[41]
[42] Patients in two studies were all performed by drainage with cutting setons.[33]
[36] The age of patients, disease duration, and follow-up period was described in a variety
of ways. The youngest age of patients in the included studies was all less than 28
days.[34]
[35] All reported disease durations were less than 30 days in 8 studies,[30]
[35]
[36]
[37]
[39]
[40]
[42]
[43] and just 1 article demonstrated the longest duration was 91 days.[38] The follow-up in most studies was longer than 6 months, and the longest one was
13 years.[35]
Table 1
Characteristics of included NRSs
Study
|
Year
|
Country
|
Total number of patient
|
Male
|
Treatment group intervention
|
Group
|
Age
Mean (min, max)
|
Disease duration
Mean ± SD or (min, max)
|
Follow-up
Mean (min, max)
|
Treatment
|
Control
|
Tian et al43
|
2001
|
China
|
30
|
19 (63.33%)
|
Drainage with fistulotomy
|
15
|
15
|
25 d, 8 y
|
5 d, 1 mo
|
NR
|
Murthi et al29
|
2002
|
UK
|
33
|
29 (87.88%)
|
Drainage with fistulotomy
|
20
|
13
|
Male: 10.5 mo (1 mo, 17 y)
Female: 7.5 y (6 y, 13 y)
|
NR
|
3 y (1 y, 5 y)
|
Xu36
|
2007
|
China
|
102
|
89 (87.25%)
|
Drainage with cutting seton
|
52
|
50
|
T: 18.3 d (5 d, 28 d)
C: 21.1 d (7 d, 27 d)
|
T: 5.5 ± 2.5 d
C: 4.5 ± 2.5 d
|
3 y
|
Kuang30
|
2007
|
China
|
31
|
24 (77.42%)
|
Drainage with fistulotomy
|
6
|
25
|
NR
|
3 d, 6 d
|
4 mo, 18 mo
|
Buddicom et al31
|
2012
|
New Zealand
|
91
|
85 (93.41%)
|
Drainage with fistulotomy
|
66
|
25
|
25 m (1 mo, 16 y)
|
NR
|
NR (patients from October 1996 to April 2009)
|
Xiao37
|
2012
|
China
|
53
|
51 (96.23%)
|
Drainage with fistulotomy
|
25
|
28
|
T: 28 d (8 d, 32 d)
C: 26 d (7 d, 28 d)
|
2 d, 6 d
|
6 mo, 2 y
|
Wang et al38
|
2015
|
China
|
112
|
69 (61.61%)
|
Drainage with fistulotomy
|
56
|
56
|
T: 3.8 y (30 d, 5 y)
C: 3.9 y (31 d, 5 y)
|
T: 25.9 ± 2.5 d, (1 d, 90 d)
C: 26.4 ± 3.5 d (1 d, 91 d)
|
2 mo
|
Juth Karlsson et al32
|
2016
|
Sweden
|
84
|
80 (95.24%)
|
Drainage with fistulotomy
|
34
|
50
|
5 m (8 d, 15 y)
|
NR
|
3 y (6 mo, 7 y)
|
Yu and Lei33
|
2017
|
China
|
30
|
30
(100%)
|
Drainage with cutting seton
|
7
|
23
|
NR
|
NR
|
> 2 mo
|
Zeng39
|
2017
|
China
|
146
|
127 (86.99%)
|
Drainage with fistulotomy
|
98
|
48
|
T: 17 d, 5 y
C: 18 d, 5 y
|
T: 2 d, 17 d
C: 2 d, 18 d
|
NR
|
Chen40
|
2017
|
China
|
76
|
42 (55.26%)
|
Drainage with fistulotomy or cutting seton
|
38
|
38
|
T: 5.85 y (7 mo, 11 y)
C: 6.3 y (6 mo, 12 y)
|
T: 2.4 d ± 0.3 d
C: 2.2 d ± 0.5 d
|
NR
|
Yao34
|
2018
|
China
|
102
|
97 (95.10%)
|
Drainage with fistulotomy
|
53
|
49
|
< 28 d
|
NR
|
6 mo
|
You and Zhang41
|
2019
|
China
|
30
|
15
(50%)
|
Drainage with fistulotomy or cutting seton
|
15
|
15
|
T: 31.43 d
C: 30.23 d
|
NR
|
NR
|
Chen et al42
|
2019
|
China
|
96
|
65 (67.71%)
|
Drainage with fistulotomy or cutting seton
|
50
|
46
|
T: 3.67 y (30 d, 6 y)
C: 3.49 y (30 d, 6 y)
|
T: 4.37 ± 1.63 d
C: 4.38 ± 1.57 d
|
3 mo
|
Tan Tanny et al12
|
2020
|
Australia
|
108
|
107 (99.07%)
|
Drainage with fistulotomy
|
85
|
26
|
T: 66.5 d (21 d, 328 d)
C: 41.5 d (18 d, 332 d)
|
NR
|
NR (patients over a 10-year period)
|
Yin et al35
|
2022
|
China
|
138
|
137 (99.28%)
|
Drainage with fistulotomy
|
65
|
73
|
T: 22.71 d, < 28 d
C: 22.36 d, < 28 d
|
T: 4 d (2 d, 5.5 d)
C: 3 d (2 d, 5 d)
|
6.5 y (4 y, 13 y)
|
Abbreviations: NR, not reported; NRSs, nonrandomized studies; SD, standard deviation.
Note: T represents the treatment group and C represents the control group.
Further treatment information of included NRSs was demonstrated in [Table 2]. The anesthetic approaches comprised general and non-general anesthesia, including
caudal and local anesthesia with or without conscious sedation.[30]
[32]
[33]
[35]
[38]
[39]
[40] Intravenous anesthesia was performed as one of the anesthetic techniques of administration.[39] Ketamine was used for inducing anesthesia, which was considered a way of basal anesthesia.[36] The locations of abscesses were mostly lateral to the anus according to the existing
information, and a more detailed description was presented at 3 and 9 o'clock in the
lithotomy position.[12]
[32]
[33]
[35]
[36]
[37] Five articles clearly stated the step of searching for fistulas before allocation.
A lacrimal probe was introduced to identify the fistula in four articles,[12]
[29]
[31]
[32] and the remaining one article reported the methods of digital anal examination and
anoscopy.[40] The internal openings were either laid open or dealt with cutting setons. Laying
open with diathermy down onto the probe was provided in a detailed description of
the surgical procedure.[12]
[31]
[32] Setons, used in the fashion of cutting, were placed through the fistula tract.[33]
[36]
[40]
[41]
[42] Antibiotics, which were in oral, topical, or intravenous use, varied in the relevant
studies.[33]
[35]
[40] Some patients received preoperative or postoperative antibiotics, and some were
treated in conjunction with the surgeries.[12]
[29]
[32]
[36]
[37]
[38]
[41]
Table 2
Summary of treatment details of included NRSs
Study
|
Mode of anesthesia
|
Abscess location
|
Searching for fistulas
before allocation
|
Surgical procedure for treating internal opening in detail
|
Antibiotic use
|
Tian et al[43]
|
NR
|
0.3–1 cm from the anal margin
|
No
|
Lay open
|
NR
|
Murthi et al[29]
|
NR
|
NR
|
Yes (except 6 patients)
|
Lay open
|
Some patients received preoperative antibiotics
|
Xu[36]
|
Ketamine anesthesia
|
Lateral to the anus, 0.5–1.5 cm from the anal margin
|
No
|
Cutting seton
|
Postoperative antibiotics use
|
Kuang[30]
|
General anesthesia
|
∼1 or 2 cm from the anal margin
|
No
|
Lay open
|
NR
|
Buddicom et al[31]
|
NR
|
NR
|
Yes (except 2 patients)
|
Lay open with diathermy dissection down onto the probe
|
NR
|
Xiao[37]
|
NR
|
Lateral to the anus
|
No
|
Lay open
|
Postoperative antibiotics use
|
Wang et al[38]
|
T: basal anesthesia
C: local, basal anesthesia or without anesthesia
|
NR
|
No
|
Lay open
|
Postoperative antibiotics use
|
Juth Karlsson et al[32]
|
General anesthesia
|
Lateral to the anus in most cases
|
Yes (except 35 patients)
|
Treating with monopolar diathermy to the probe
|
Some patients received antibiotic therapy in conjunction with surgical treatment
|
Yu and Lei[33]
|
Local anesthesia
|
Lateral to the anus
|
No
|
Cutting seton
|
Topical antibiotics
|
Zeng[39]
|
Local or intravenous anesthesia
|
NR
|
No
|
Lay open
|
NR
|
Chen[40]
|
T: caudal anesthesia
C: anesthesia
|
NR
|
Yes
|
Lay open or cutting seton
|
T: topical antibiotics
C: None
|
Yao[34]
|
NR
|
NR
|
No
|
Lay open
|
NR
|
You and Zhang[41]
|
Anesthesia
|
NR
|
No
|
Lay open or cutting seton
|
Postoperative antibiotics use
|
Chen et al[42]
|
Basal anesthesia
|
NR
|
No
|
Lay open or cutting seton
|
NR
|
Tan Tanny et al[12]
|
NR
|
Lateral to the anus
|
Yes
|
Lay open with diathermy down onto the probe
|
Preoperative antibiotics use
|
Yin et al[35]
|
T: conscious sedation and local anesthesia
C: local anesthesia
|
Lateral to the anus in most cases
mainly at 3 and 9 o'clock
|
No
|
Lay open with diathermy
|
Intravenous antibiotics use
|
Abbreviations: NR, not reported; NRSs, nonrandomized studies.
Note: T represents the treatment group and C represents the control group.
Risk of Bias Assessment
Overall, the results of the methodological quality assessment of the 16 studies were
satisfactory, which are summarized in [Supplementary Table S2]. Four of them were assessed as high-quality,[35]
[36]
[37]
[42] and all the remaining were considered of moderate quality.[12]
[29]
[30]
[31]
[32]
[33]
[34]
[38]
[39]
[40]
[41]
[43] There was only one study that had no description of the derivation of the nonexposed
cohort.[43] All studies controlled for age based on design or analysis, which was deemed the
most important factor. Each study could be awarded 2 stars when other factors were
also considered, such as the disease duration.[33]
[35]
[36]
[37]
[38]
[39]
[40]
[42]
[43] Outcomes in eight studies were identified via record linkage.[12]
[29]
[30]
[31]
[32]
[33]
[35]
[42] The follow-up period (equal to or more than 6 months) was regarded as long enough
for outcomes to occur.[29]
[32]
[34]
[35]
[36]
[37]
Outcome Parameter
An overview of the primary outcomes and secondary outcomes is tabulated in [Table 3]. Outcomes with sufficient data available were eligible for further meta-analysis.
Table 3
Outcome variables in the analyzed NRSs
Study
|
Number of PAs
|
Healing rate
|
Fistula formation
|
Fecal incontinence
|
Wound healing time (d)
Mean ± SD or estimation
|
Treatment
|
Control
|
Treatment
|
Control
|
Treatment
|
Control
|
Treatment
|
Control
|
Tian et al[43]
|
30
|
14/15 (93.33%)
|
10/15 (66.67%)
|
1/15 (6.67%)
|
5/15 (33.33%)
|
NR
|
NR
|
Murthi et al[29]
|
33
|
20/20 (100%)
|
6/13 (46.15%)
|
0/20 (0%)
|
5/13 (38.46%)
|
NR
|
NR
|
Xu[36]
|
102
|
49/52 (94.23%)
|
21/50 (42.00%)
|
NR
|
NR
|
24.5 ± 3.5
|
28.5 ± 4.5
|
Kuang[30]
|
31
|
6/6 (100%)
|
22/25 (88.00%)
|
0/6 (0%)
|
3/25 (12%)
|
NR
|
NR
|
Buddicom et al[31]
|
91
|
61/66 (92.42%)
|
19/25 (76.00%)
|
NR
|
NR
|
NR
|
Xiao[37]
|
53
|
25/25 (100%)
|
15/28 (53.57%)
|
0/25 (0%)
|
6/28 (21.43%)
|
NR
|
NR
|
Wang et al[38]
|
112
|
55/56 (98.21%)
|
49/56 (87.50%)
|
NR
|
NR
|
12.6 ± 1.9
|
20.5 ± 0.9
|
Juth Karlsson et al[32]
|
84
|
31/34 (91.18%)
|
30/50 (60.00%)
|
NR
|
NR
|
NR
|
Yu and Lei[33]
|
30
|
7/7 (100%)
|
21/23 (91.30%)
|
NR
|
NR
|
NR
|
Zeng[39]
|
146
|
96/98 (97.96%)
|
39/48 (81.25%)
|
NR
|
NR
|
12.7 ± 1.8
|
20.6 ± 1.1
|
Chen[40]
|
76
|
35/38 (92.11%)
|
27/38 (71.05%)
|
0/38 (0%)
|
3/38 (7.89%)
|
1
|
2
|
NR
|
Yao[34]
|
102
|
51/53 (96.23%)
|
41/49 (83.67%)
|
NR
|
NR
|
16.8 ± 2.9
|
15.1 ± 2.6
|
You and Zhang[41]
|
30
|
9/15 (60.00%)
|
6/15 (40.00%)
|
1/15 (6.67%)
|
5/15 (33.33%)
|
NR
|
NR
|
Chen et al[42]
|
96
|
31/50 (62.00%)
|
19/46 (41.30%)
|
2/50 (4%)
|
5/46 (10.87%)
|
Wexner score: T < C
anal manometry: T > C
|
NR
|
Tan Tanny et al[12]
|
111
|
72/85 (84.71%)
|
17/26 (65.38%)
|
NR
|
NR
|
NR
|
Yin et al[35]
|
138
|
64/65 (98.46%)
|
59/73 (80.82%)
|
1/65 (1.54%)
|
10/73 (13.70%)
|
0
|
0
|
21
|
14
|
Abbreviations: NR, not reported; NRSs, nonrandomized studies; PAs, perianal abscesses;
SD, standard deviation.
Note: T represents the treatment group and C represents the control group. Anorectal
manometry: Resting pressure and maximum squeezing pressure.
Healing rate: The healing rate in the treatment group ranged from 60 to 100%, and most were above
90% except for three studies.[12]
[41]
[42] In the control group, almost all the studies demonstrated a healing rate of less
than 90%, and the least was 40%.[41] Only 1 trial described that 21 of 23 participants were cured by I&D alone, revealing
a higher healing rate of 91.30%.[33] Since no conspicuous heterogeneity appeared among the studies, the fixed-effect
model was employed for merging and calculating the pooled OR and 95% CI. The pooled
results indicated that there was a significant difference between the treatment group
and the control group (OR: 5.76, 95% CI: 4.04–8.22, I2
= 22%, p < 0.001) ([Fig. 2]). The funnel plot did not suggest any obvious publication bias ([Supplementary Fig. S1]).
Fig. 2 Forest plot of healing rate for the treatment group versus the control group. CI,
confidence interval; I&DF, treatment, incision, and drainage with primary fistula
treatment; I&D, control, incision, and drainage.
Fistula formation rate: Eight out of 16 studies had reported cases of fistula formations during the time
of study or follow-up period.[29]
[30]
[35]
[37]
[40]
[41]
[42]
[43] None of the patients in the treatment group developed a fistula in 4 trials,[29]
[30]
[37]
[40] and the highest formation rate was 6.67% in the 2 articles.[41]
[43] The fistula formation rates were remarkably higher in the control group, which varied
from 7.89 to 38.46%. There was no evidence of heterogeneity among these relevant studies.
Primary fistula treatment of PAs in children gave rise to an obvious reduction in
the risk of fistula formation after surgical drainage (OR: 0. 14, 95% CI: 0.06–0.32,
I2
= 0%, p < 0.001) ([Fig. 3]).
Fig. 3 Forest plot of fistula formation rate for the treatment group versus the control
group. CI, confidence interval; I&DF, treatment, incision, and drainage with primary
fistula treatment; I&D, control, incision, and drainage.
Fecal incontinence: Fecal incontinence was only reported in three Chinese studies, two of which documented
the number of patients, and the other presented a comparison of preoperative and postoperative
anal manometry combined with the Wexner Incontinence Score.[35]
[40]
[42] There was a transient decrease in anal resting pressure and maximum squeeze pressure,
along with a slight increase in the Wexner score 1 month after surgery in both groups.
This situation had changed and recovered after 3 months postoperatively, and the treatment
group had significantly more improvement than the control group had in the Wexner
score.[42] No other information was available on the consequence of fecal incontinence in the
remaining articles.
Wound healing time: Five articles with 600 patients showed the wound healing time, among which 4 were
reported as mean ± SD,[34]
[36]
[38]
[39] and 1 recorded estimated time.[35] Three of them indicated that the average time for wound healing was shorter in the
treatment group than that in the control group,[36]
[38]
[39] and the opposite situation was observed in two articles.[34]
[35] There was also a discrepancy in the length of time between both groups. For instance,
the shortest mean duration was 12.6 days and the longest was 24.5 days in the treatment
group. Due to the large degree of heterogeneity, it was not possible to carry out
a quantitative meta-analysis to compare the efficacy of two types of interventions
in wound healing time.
Discussion
PAs and fistulas represent different entities of the same disease process, indicating
the acute and chronic inflammatory phases of perianal infection. Although the disease
primarily affects adults, it has also been known to afflict children for many years.
I&D is the mainstream surgical treatment with the advantage of a fast, simple, and
efficient procedure. For most abscesses with superficial fistulas, primary fistula
treatment has been previously advocated to prevent the recurrence of PAs and the development
of fistulas based on the theory of cryptoglandular origin.[44]
[45] This aggressive surgical approach may increase the likelihood of fecal incontinence,
so it remains controversial.
To the best of our knowledge, this is the first systematic review and meta-analysis
for assessing postoperative outcomes and relevant information between I&DF and I&D
in children with PAs. Our major objective was to evaluate the clinical efficacy and
safety of both surgical approaches. The pooled results revealed a significant elevation
in the healing rate for patients with I&DF. Of 1,265 included abscesses, 626 (91.39%)
in the treatment group versus 401 (69.14%) in the control group illustrated complete
solutions with no further intervention over the follow-up period according to all
16 NRSs. The odds of fistula formation rate in children treated with I&DF was 86%
lower than those treated with I&D. Among eight included articles with available data,
four studies reported no incidence of progression to fistulas in the treatment group.[29]
[30]
[37]
[40] Regarding the results of our meta-analysis, the positive effects of primary fistula
treatment seemed to be more pronounced than those of drainage alone. Concerning the
wound healing time, patients treated with I&DF appeared to recover more quickly in
three studies.[36]
[38]
[39] But the differences were too large to carry out the pooled analysis, which contributed
to the considerable heterogeneity. We speculated that several factors might influence
the inconsistency, including the size of abscesses and surgical incisions, age variation,
and postoperative care.
Yet, there was very little evidence of fecal incontinence and no consensus had been
reached on the assessment in children. Only three studies from China, among which
one was written in English, mentioned the postoperative anal function of patients.[35]
[40]
[42] Although the surgery might have an impact on the anal sphincter, the results revealed
less possibility of incontinence and better preservation of anal function in the treatment
group than that in the control group. In addition, another three English articles
indicated that a vast majority of fistulas with relatively superficial positions involved
less or no sphincter in children and thus the risk of incontinence was supposed to
be small.[12]
[31]
[32] This might be the reason why investigators did not conduct the follow-up on fecal
incontinence. From our perspective, children tend to have a high level of limb activity,
making it challenging to conduct quiet and cooperative examinations such as anal manometry
and perianal magnetic resonance imaging. Moreover, different patterns of bowel movements
can impact the assessment of the severity of fecal incontinence. This also poses a
difficulty in establishing a standardized evaluation process for anal sphincter function
in the pediatric population. Thus, longer follow-ups are warranted to determine whether
the effects persist into adulthood or not.
It has been demonstrated that coexisting fistulas are present in approximately 60
to 76% of children at the initial treatment of PAs.[12]
[29]
[31]
[32] Examinations for fistulas were not applied in all cases due to the potential harm
to exploration and the risk of false opening and iatrogenic tract.[46] Nevertheless, primary fistula treatment was indeed considered to be beneficial for
children to decrease the likelihood of recurrences and avoid secondary surgery.[47] The key to improving efficacy and safety depends on identifying the accurate location
of internal openings contiguous with fistulas, as well as figuring out the amount
of anal sphincter involved. More detailed preoperative examinations are necessary,
such as transcutaneous perianal ultrasonography.[48] That also requires skilled and experienced surgeons with sufficient knowledge of
anatomy, who will probe the corresponding anal crypt gently but thoroughly to look
for a fistula. On the other hand, the abnormal deep and thick crypts of Morgagni have
been recognized as a cause of cryptitis in children, which can easily develop into
a PA.[49] Therefore, I&DF will enable to prevent the persistent infections at the origin of
the defects.[50] Usually, the associated fistulas are simple intersphincteric or subcutaneous types
and locate superficially with less penetration through muscles in children, especially
in infants.[14]
[51]
[52]
[53] For internal openings in high positions, cutting setons are more favored to minimize
the damage to the anal function. There have been few reports about the functional
or anatomical impact of this surgical procedure on the anal sphincter in children
currently.[54] So, we are unable to demonstrate that primary fistula treatment should be advocated
under all circumstances.
All the included studies with nonrandomized designs and limited data might have potential
bias and confounding factors, which could affect the results. Among these studies,
12 trials were from China and 4 were from other countries. The variation of the study
population and a broad spectrum of ages could be the reason for the disparity in treatment
outcomes. Not all the studies had documented whether these abscesses were first-time
presentations or recurrent abscesses. The available disease durations were almost
less than 2 weeks, while only 1 article reported an average time of approximately
25 days.[38] This suggested the possibility of bias since a longer duration or recurrence was
more likely to be accompanied by an underlying fistula. Consequently, those patients
might be more inclined to receive primary fistula treatment. The processes of searching
for fistulas during surgery were explicitly mentioned only in 5 studies, among which
43 patients did not receive the search for fistulas.[12]
[29]
[31]
[32]
[40] Patients who had undergone this important procedure were also more likely to be
allocated to the treatment group. Antibiotics, which had been implemented in different
ways, were applied in 10 trials.[12]
[29]
[32]
[33]
[35]
[36]
[37]
[38]
[40]
[41] Some believed antibiotic administration showed benefits for PAs in children while
others found no effect on the recurrences.[12]
[29]
[32] It was hard to say what could be the role of antibiotics in treating abscesses,
but this was really a possible confounding factor that might influence the results.
Our systematic review and meta-analysis especially focused on pediatric patients who
suffered from PAs and were treated by surgical interventions (I&DF and I&D). The results
suggested that primary fistula treatment was considered beneficial at the time of
I&D, which might improve the healing rate and decrease the likelihood of fistula formation.
Although there was insufficient evidence to support that such an aggressive procedure
did not cause apparent injuries to anal sphincters, we speculated the superficial
location of abscesses and protective treatments for high internal openings were associated
with minor postoperative fecal incontinence. A thorough and gentle search for fistulas
by skilled and experienced surgeons intraoperatively is demanded to avoid excessive
tissue damage and preserve anal function. Well-established assessment of postoperative
anal function and detailed research information will be necessary to provide strong
and supportive evidence. We would like to revisit this issue when more useful data
from multicenter, randomized, double-blind clinical trials of high quality can be
obtained in the future.