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Abstract
Background Although adhesive strapping (AS) for pediatric umbilical hernia (UH), which was once obsolete, has been reconsidered as a common practice in Japan, its efficacy is still unclear. This study aimed to evaluate its efficacy by reviewing related articles.
Methods A comprehensive literature search of PubMed, Cochrane, Google Scholar, and Igaku Chuo Zasshi via Ichushi-Web was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Cohort studies reporting on the UH closure rate after AS compared with observation-only management were included.
Results A total of 10 cohort studies were included, and the overall UH closure rate was not statistically significant (p=0.31, risk ratio (RR)=0.76, 95% confidence interval (CI) 0.45 to 1.28). However, there were significant differences in the UH closure rate at the age of 6 months (p<0.01, RR=0.55, 95% CI 0.41 to 0.75) and the efficacy of preventing protruding umbilici with redundant skin (p=0.049, RR=0.16, 95% CI 0.03 to 0.99).
Conclusions Although the efficacy of AS on UH compared with observation-only management did not differ in terms of the UH closure rate, the application of AS may be effective for faster UH closure and the prevention of protruding umbilici. However, due to the high heterogeneity of the study, further large-scale studies, particularly randomized controlled trials, are warranted to reach a conclusion.
PROSPERO registration number CRD42022314417.
- Surgery, Plastic
- Pediatrics
Data availability statement
Data are available upon reasonable request.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
The present treatment of pediatric umbilical hernia is observation, although adhesive strapping was conducted decades ago.
In Japan, adhesive strapping is regarded as a basic treatment due to the accumulation of retrospective and prospective studies.
There is no comprehensive review comparing the efficacy of adhesive strapping and observation-only treatment.
WHAT THIS STUDY ADDS
We found that there was no significant difference in the overall closure rate of pediatric umbilical hernia.
We found that the application of adhesive strapping may be effective for faster umbilical hernia closure and the prevention of protruding umbilici.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
There is insufficient number of studies focusing on the efficacy of adhesive strapping on pediatric umbilical hernia, and thus further studies, including randomized controlled studies, are warranted to reach a conclusion.
Adhesive strapping could be considered an alternative treatment option for cosmetic purposes.
Introduction
Pediatric umbilical hernia (UH) is a common disease that occurs in 10%–20% of newborns.1 Despite its high prevalence, 80% of patients with UH are expected to heal spontaneously before reaching 1 year of age and 90% before 2 years of age without any treatment.2
Since the mid-20th century, adhesive strapping (AS), which involves strapping the abdomen with adhesive tape to keep the UH reduced, has been considered a useful method, and several studies and case reports regarding this maneuver have been published.3–8 However, as studies on its usage became limited, its efficacy was doubted and AS became obsolete.9–12 Therefore, in most countries, children are under observation for UH until the age of 2 years. Surgical repair is considered when UH persists beyond that age.13
In Japan, AS has been recently reconsidered a standard procedure. This is because some studies have revealed that AS accelerates healing and suppresses umbilical protrusion after hernia closure.2 14–18 However, its efficacy is still unclear because there are no randomized controlled trials; several cohort studies have investigated the strategy. Therefore, this systematic review and meta-analysis aims to reveal the efficacy of AS for UH compared with observation-only management by analyzing previous cohort studies.
Herein, the primary outcome was the change in the UH closure rate. The secondary outcomes were the closure rate at 6 months of age, among patients with a large hernia, among mature or premature infants, and the rate of children with umbilical protrusion with redundant skin at the end of the observation period. We examined the closure rates with data in recent studies and reviewed the complications of AS.
Methods
We performed a systematic review and meta-analysis of the related literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (online supplemental file 1) to conduct this meta-analysis of cohort studies, which was registered on PROSPERO (registration number CRD42022314417).
Supplemental material
Search strategy of the literature
First, databases including PubMed, Cochrane, Google Scholar, and Igaku Chuo Zasshi via Ichushi-Web (a Japanese medical abstract database) were searched independently by two investigators (TS and KT). The search included studies published before March 8, 2022, without any limitation on publication year. The search terms “umbilical hernia” and “strapping” were used in PubMed and Cochrane, and “umbilical hernia,” “strapping,” and “pediatric” were used in Google Scholar. We used equivalent words in Japanese when searching Ichushi-Web. Second, relevant articles were identified through a manual search of secondary sources, including references to initially identified studies and a search of reviews and commentaries. The search was limited to cohort studies in children, and all cohort studies that reported on the closure rate of UH after AS in comparison with that after observation-only management were eligible for inclusion. The other inclusion criterion was an observation period of at least up to 1 year of age. If the observation period was not mentioned, the authors evaluated whether the period was acceptable. Japanese articles without an English abstract were excluded.
Eligibility was assessed by two investigators (TS and KT) following a three-stage procedure: title screening, abstract screening, and whole article screening. The Newcastle-Ottawa Quality Assessment (NOS) was used to access the quality of the included studies. In the NOS, 9 scores can be maximally awarded by adding up to 4 scores for selection criteria, 2 scores for comparability, and 3 scores for the outcome. We defined age as the most important factor and the size of the UH defect as the second most important factor for comparability. We designated scores of 0–3, 4–6, and 7–9 as low-quality, moderate-quality, and high-quality studies, respectively. Any differences in the procedure were resolved by consensus (TS and KT).
Data extraction
The following data were extracted from the included studies: publication year, country, period of intervention, number of patients who underwent AS and observation-only management as a control arm, sex, proportion of large and small UH, proportion of premature and mature infants, age at which AS was first applied, observation period, inclusion and exclusion criteria, AS procedure, study outcome, UH closure rate at the end of the study and age of 6 months, UH closure rate in large hernias, UH closure rate among premature or mature infants with hernia, overall AS duration, age when the UH was cured, incidence of protrusion of umbilicus with redundant skin, and complications.
Statistical analysis
All analyses except that for publication bias were implemented using EZR (V.1.54; Saitama Medical Center, Jichi Medical University, Saitama, Japan). We chose risk ratios (RRs) and 95% confidence interval (CIs) as the main outcome indices. If not reported in the primary studies, RRs and other associated variance components were calculated from the original data. Forest plots were produced to visualize the assessment of the RRs across studies. I2 values were used to evaluate the heterogeneity across studies. Values of 0%–25% represented minimal heterogeneity, 26%–75% represented moderate heterogeneity, and >75% represented substantial heterogeneity. Summary estimates of the RRs were performed using Mantel-Haenszel random-effects models. Publication bias was assessed by inspection of the funnel plots for asymmetry with Begg’s and Egger’s tests using the metafor package of R software (R Foundation).19
Results
Study selection
In total, 129 studies were identified through database searching and manual searching (figure 1). After removing duplicates, two reviewers identified eligible articles independently by title and abstract screening. Studies that did not meet our inclusion criteria were removed, and 12 studies were assessed for eligibility. After excluding articles with no English abstract and insufficient data, finally, 10 studies were included in our analysis (figure 1).
Flow chart of the selection of eligible studies.
Study characteristics and quality assessment
The general characteristics of the included studies are shown in tables 1 and 2. The 10 included studies were cohort studies: 4 articles from Europe, Australia, and the USA were published in the mid-20th century, and 6 articles from Japan were published after 2000. AS was commenced before the age of 1 year in all cases, particularly during the first 6 months of life. The observation periods were at least 12 months. The qualities of the eligible studies were assessed using the NOS, which suggested that they were of high quality: a score of 7 in five studies and a score of 8 in five studies (online supplemental file 2).
Supplemental material
Characteristics of the cohort studies included in the analysis
Criteria for AS, the procedure, and the outcome of the studies included
AS procedure
Regarding the initiation age, eight studies mostly applied AS within the first 6 months.2 5 9 14 16 17 20 21 One study did not mention it clearly, but the author probably applied it to patients of less than 6 months.10 Infants less than 1 year old were included in a study.11 There were several differences in the procedures of the included studies (table 2). First, in the studies before 2000, an elastic plaster or tape was directly applied after the hernia was reduced. However, in the latest studies after 2000, a cotton ball or a plug was inserted on the umbilicus, and subsequently plaster was placed in all studies except one.14 Second, the frequency of changing AS varied in studies. In four studies, AS was changed weekly, in two studies every 2–3 weeks, in one study every 4 weeks, and two studies did not determine the specific period except when a plaster became dirty or peeled off and the frequency was not mentioned. Third, AS was changed by doctors or nurses in two studies and was changed by guardians at home in three studies. The other five studies did not mention who changed AS. Two studies reported that 7.8% and 12.6% of patients discontinued AS due to skin trouble.16 21 One study excluded two patients who could not continue AS.5 The overall duration of AS was reported in four studies.2 11 14 21 The shortest duration was reported to be 11 days2 and the longest was 10 months.14 The average duration was mentioned in three studies: 2 months in two studies14 21 and 49 days in the other.2
Efficacy of the intervention
Overall UH closure in the AS group and observation group
The meta-analysis comparing AS and observation-only management was conducted on 10 cohort studies (table 3). We compared unsuccessful UH closure rates of each group to calculate the RR, and there was no statistical significance between the two groups as per the forest plot shown in figure 2 (p=0.31, RR=0.76, 95% CI 0.45 to 1.28; heterogeneity was found: p<0.01, I2=71%).
Summary of outcomes of the studies included
Forest plot showing the analysis for the overall unsuccessful UH closure comparing the AS group and observation-only group. Events: unsuccessful UH closure. AS, adhesive strapping; RR, risk ratio; UH, umbilical hernia.
UH closure rate at 6 months of age
Five studies compared the UH closure rate at the age of 6 months (table 3).2 5 9 14 17 The closure rates of UH were consistently higher in the AS group in four studies, and the meta-analysis showed a significant difference between the AS group and the observation group, as presented in the forest plot (p<0.01, RR=0.55, 95% CI 0.41 to 0.75; moderate heterogeneity was found: p=0.03, I2=63%) (figure 3A).
Forest plots of secondary endpoints comparing the AS group and the observation-only group: (A) unsuccessful UH closure at the age of 6 months old, (B) among large UH, (C) event of umbilical protrusion with redundant skin, and (D) among only recent studies. Events: unsuccessful UH closure. AS, adhesive strapping; RR, risk ratio; UH, umbilical hernia.
Efficacy of AS on UH closure among large hernias
Four studies evaluated the efficacy of AS on large hernias (table 3).5 9 10 20 The definitions of large hernia varied; the defect diameter was >5 mm in two studies5 20 and >10 mm in another study.10 The other study defined a large hernia as an hernia with an orifice that permits passage of a fingertip.9 Therefore, this analysis was performed with four studies that had different definitions. Three studies5 9 20 revealed a higher cure rate in the AS group than in the observation group, except one.10 According to the forest plot, however, there was no significant difference between the two groups (p=0.33, RR=0.70, 95% CI 0.33 to 1.44; moderate heterogeneity was found: p=0.08, I2=55%) (figure 3B). When analyzing two studies5 20 that defined hernias >5 mm in diameter as large hernias, there was also no significant difference (p=0.15, RR=0.46, 95% CI 0.16 to 1.31; moderate heterogeneity was found: p=0.21, I2=35%).
Efficacy of AS among mature and premature infants
Only one study reported the efficacy of AS based on maturity.16 Among premature infants, the UH closure rate after AS was 80%. In the study, there were no premature infants who underwent observation. Among mature infants, the closure rates with and without AS were reported as 85.7% and 90.0%, respectively.
Efficacy for prevention of umbilical protrusion with redundant skin
Three studies evaluated the efficacy of AS in the prevention of umbilical protrusion (table 3).14 16 20 These studies defined the condition in which the fascial defect was closed but the umbilicus protruded, with excess skin as umbilical protrusion with redundant skin. According to the forest plot, there was a significant difference between the AS and the observation group in preventing umbilical protrusion (p=0.049, RR=0.16, 95% CI 0.03 to 0.99; heterogeneity was moderate: p=0.18, I2=41%) (figure 3C).
Efficacy of AS among recent studies
Six studies were published after 2000, which were all from Japan2 14 16 17 20 21 (table 3). There was no significant difference between the two groups in the rate of unsuccessful closure (p=0.11, RR=0.58, 95% CI 0.29 to 1.13; heterogeneity was found: p=0. 10, I2=45%) (figure 3D).
AS-related complications
Six studies reported complications due to AS, and the incidence rates were between 1.1% and 41.2% (table 3). The most common complication of AS was skin irritation, which caused discontinuation of AS when it was severe. However, the majority of patients were tolerant and they were able to complete AS after a short refraining period. Apart from skin complications, one case of strangulation was reported and we counted it as unsuccessful.10
Publication bias
Visual inspection of the funnel plot of the primary outcome revealed some asymmetry (online supplemental file 2). However, Begg’s test and Egger’s test did suggest any significant publication bias (Begg’s test: τ=0.111, p=0.728; Egger’s test: t=−1.457, p=0.183). Funnel plots of secondary outcomes were also visualized (online supplemental file 2). However, Begg’s and Egger’s tests were not conducted because of the small number of included studies.
Discussion
The technique to treat pediatric UH, called adhesive strapping, compression, or binding, has regained popularity in Japan. There are many minor differences in this method (table 2), but the concept is the same: compressing the UH and maintaining it inward. As an example, we provide photos demonstrating how to conduct it at our site in online supplemental file 2.
To our knowledge, our meta-analysis is the first reported study to examine the evidence from cohort studies on the efficacy of AS on UH. Our meta-analysis analyzed information on a total of 684 patients with AS and 464 patients without AS. There was no significant difference in the efficacy of AS on the overall UH closure and that of large hernia compared with observation-only management. Furthermore, the subgroup analysis of recent studies did not show a significant difference.
We believe that the factors that affected our results were the sample sizes and the proportion of large hernias in the included studies. Regarding sample sizes, 80% of patients with UH are expected to heal spontaneously before attaining 1 year of age and 90% before 2 years of age. Therefore, we estimated the closure rates by AS and observation-only management as 95% and 90%, respectively. The necessary sample size is calculated as 475 cases each with α=0.05 and 1−β=0.80. We estimated these sample sizes as 85% and 80%, respectively, and the sample size needed rose to 946 each. The sample sizes of the included studies in our study were mostly less than 100 in each arm. Therefore, we could not exclude the possibility that insufficient sample sizes affected the results.
The proportion of large hernias in each arm should also be considered when interpreting the results. Some studies indicated that the size of the UH did not influence its closure.18 22–24 For instance, Heifetz et al23 reported that 72 out of 78 patients (92%) with UH >0.5 cm were cured spontaneously within 4 years. Meier et al24 revealed that spontaneous closure of UHs >10 mm in diameter with at least 5 mm protrusion seemed to occur by the age of 14. However, Walker25 indicated that the diameter of the internal fascial ring was the most relevant parameter to determine whether spontaneous UH closure would be accomplished and that the healing rate differed according to the UH size. In our study, the proportion of large hernias in the AS group was higher in four studies5 9 10 20 and was not mentioned in five studies. One study reported that the average size of UH in the AS group was smaller than that in the observation group.17 Although we did not show an advantage of AS for large hernias, there would be several variabilities in this subgroup analysis, such as insufficient patient numbers, differences in the proportion between the two groups, and the definition of “large hernias.” From these points of view, randomized controlled trials with strict definitions of large hernias measured by ultrasound are warranted to reach a conclusion.
Although our study did not show the significance of the efficacy of AS on the closure rate, it indicated some possible advantages through secondary outcomes. One of them was the efficacy of earlier UH closure.
As Cresson and Pilling26 described, there was already some agreement in the 1950s that AS has no advantage after the age of 6 months. While Cresson and Pilling also noted from their experience that AS rarely hastened UH healing,26 our result corresponded to a previous study that revealed that the treatment duration was shorter in the AS group than in the observation group.27 Once AS is applied at an earlier age, it accelerates the healing of UH and the duration of UH existence is expected to be shortened. Consequently, it reduces the burden and anxiety of parents. Therefore, it is rational that AS was mostly applied within 6 months in recent studies to close UH earlier.2 14 16 17 20 21 The earliest time of application was less than 1 month of age, 18 days old.20 However, no study has revealed how early AS could be safely applied and how effective AS would be when applied earlier. Regarding premature infants, it was also uncertain whether the corrected age should be adopted rather than the real age. Factors such as umbilical condition, gestational age, and body weight should likely be considered for AS application.
Another possible benefit of AS to babies with UH is that AS prevents umbilical protrusion with redundant skin. In most studies, UH closure was defined as the closure of the orifice regardless of the umbilical figure. Therefore, if an umbilical defect is closed spontaneously, patients with protruding umbilicus will undergo umbilicoplasty for cosmetic reasons. According to the included studies, the prevalence of the protruding umbilicus at the end of the study was 0%–9.4% and 10%–18.8% in the AS and observation groups, respectively. This result corresponded to a study that gathered data from multiple institutions through questionnaires; it reported that the prevalence rates of redundant skin among patients who were regarded as cured from UH were 107 of 908 (11.8%) in the AS group and 33 of 146 (22.8%) in the observation-only group.28 Regarding umbilicoplasty, Hayashida et al21 reported that the operation time of patients who tried AS was shorter than that of patients without AS. The authors also mentioned that the difficulty of umbilicoplasty depended on the existence of redundant skin. Therefore, if AS prevents redundant skin and disfigurement of the umbilicus, it may be beneficial to patients.
Prematurity is regarded as a factor for UH because there is a difference in UH prevalence between mature and premature infants.3 12 We did not find articles that compared the UH closure rates by maturity, but Kurobe et al16 reported that the closure rates among mature and premature infants who were treated with AS at the end of the study were 85.7% and 80%, respectively. Although they seemed different, it was unclear whether closure rates would change if the corrected age was used.
AS was implemented mainly in the mid-20th century and after the year 2000. Particularly in Japan, AS was reconsidered as a practical treatment for UH because many retrospective studies indicated its positive effects on UH closure. The discontinuation rate of AS was reported to be approximately 10%, and skin irritation due to plasters and tape is one of the determinants in deciding whether to continue AS. Since more skin-friendly plasters and tapes have been developed, we expected that the AS completion rate would rise and increase the successful UH closure rate with a lower complication rate. In our study, however, the comparison of the AS group with the observation group on UH closure among recent studies, all published in Japan, did not show a significant difference.
The most severe complications of UH are strangulation, incarceration, and evisceration, but their occurrence rates are considered low.13 29 Therefore, based on the prevention of these complications, AS has few advantages for patients. If AS is applied for earlier closure or the prevention of redundant skin, AS-related complications should be taken into consideration. The most common problem was skin irritation or dermatitis from a plaster, which was the most decisive factor regarding AS continuation. However, these skin problems were relatively prevented using skin-friendly plasters and films or by introducing a short refraining period. Other complications reported in Japanese literature were massive bleeding from the umbilical artery, strangulation due to compression, and UH perforation caused by skin ulceration, which were all reported as case reports.30 One study reported that AS caused delayed UH closure and increased severity, but other articles did not report similar events.12 Despite the low prevalence, doctors need to explain these possibilities and pay attention to the umbilical condition when changing AS.
This study had several limitations. First, this was a meta-analysis of cohort studies with somewhat different endpoints. While some studies provided the specific period of closure, others adopted whether the UH was closed at a specific age. Second, the sample sizes of each study were probably insufficient to reach a conclusion. Third, each meta-analysis, particularly that of the primary outcome and that of the efficacy at 6 months old, contained moderate heterogeneity. We presumed that this was due to the insufficient sample size of the included studies. Following the protocol, we did not conduct post-hoc subgroup analyses to determine other factors that affected the results. However, when related studies are accumulated, subgroup analyses should be conducted according to differences in follow-up periods, AS procedures such as with or without plugs to reduce UH, and the UH closure rate in the observation group. Next, there was a possibility that we may not have found some old studies. Finally, recent studies were only conducted in Japan; thus, language bias may exist. Therefore, further studies at higher evidence levels are necessary to reach a definitive conclusion.
In conclusion, our study did not clarify the significant difference in the overall efficacy of AS on UH closure. However, there might be advantages to accelerating the closure speed and preventing protruding umbilici with redundant skin. Due to the high heterogeneity of our study, further studies at higher evidence levels are warranted before reaching a definitive conclusion.
Data availability statement
Data are available upon reasonable request.
Ethics statements
Patient consent for publication
Ethics approval
This study is a systematic review and meta-analysis and the data were extracted from the original studies. No patients or animals were involved in this study. Therefore, this study did not require ethics approval.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors TS contributed to conceptualization, data curation, formal analysis, investigation, methodology, resources, software, visualization, and writing—original draft, review, and editing. KT contributed to conceptualization, data curation, formal analysis, investigation, methodology, resources, validation, visualization, and writing—review and editing. KU contributed to conceptualization and writing—review and editing. KY contributed to conceptualization, supervision, validation, writing—review and editing, and the guarantor of study. All authors reviewed the results and approved the final version of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.