Recurrence Rates After Intussusception EnemaReduction: A Meta-analysis

abstractBACKGROUND AND OBJECTIVE: Reported rates of recurrence after en-ema reduction for intussusception are variable. Concerns for recur-rence influence postreduction management. The objective of thisstudy was to conduct a systematic review and meta-analysis to esti-mate overall, 24-hour, and 48-hour recurrence rates after enema re-duction in children.

METHODS: PubMed, Cochrane Database, and OVID Medline weresearched from 1946 through December 2011 using the search terms:intussusception, recurrence, and enema. Sixty-nine studies of patientsage 0 to 18 years with radiographically proven intussusception re-duced by enema that report the number of enema reductions andthe number of recurrences were included. Extraction was done bythe primary author (M.P.G.) with 10% of included studies independentlyaudited to ensure concordance.

RESULTS: Overall recurrence rates were 12.7% (95% confidence inter-val [CI]: 11.1%–14.4%, I2 = 28.8%) for contrast enema (CE), 7.5% (95%CI: 5.7%–9.8%, I2 = 52.4%) for ultrasound-guided noncontrast enema(UGNCE), and 8.5% (95% CI: 6.9%–10.4%, I2 = 50.1%) for fluoroscopy-guided air enema (FGAE). Recurrence rates within 24 hours were 3.9%(95% CI: 2.2%–6.7%, I2 = 47.0%) for CE, 3.9% (95% CI: 1.5%–10.1%, I2 =0.0%) for UGNCE, and 2.2% (95% CI: 0.7%–6.5%, I2 = 59.8%) for FGAE.Recurrence rates within 48 hours were 5.4% (95% CI 3.7%–7.8%, I2 =32.3%) for CE, 6.6% (95% CI: 4.0%–10.7%, I2 = 0.0%) for UGNCE, and2.7% (95% CI: 1.2%–6.5%, I2 = 73.8%) for FGAE. Most included studiesare retrospective and vary in quality of reporting. Few studies re-ported detailed patient characteristics including timing of recurren-ces.

CONCLUSIONS: The risk of early (within 48 hours) recurrence afterenema reduction is low, suggesting outpatient management of well-appearing patients should be considered. Pediatrics 2014;134:110–119

AUTHORS: Matthew P. Gray, MD,a Shun-Hwa Li, PhD,b,c

Raymond G. Hoffmann, PhD,b,c and Marc H. Gorelick, MD,MSCEa,b

Sections of aEmergency Medicine, and cQuantitative HealthSciences, Department of Pediatrics, Medical College of Wisconsin,Milwaukee, Wisconsin; and bChildren’s Research Institute,Children’s Hospital of Wisconsin, Milwaukee, Wisconsin

KEY WORDSintussusception, recurrence, enema

ABBREVIATIONSCE—contrast enemaCI—confidence intervalFGAE—fluoroscopy-guided air enemaUGNCE—ultrasound-guided noncontrast enema

Dr Gray conceptualized and designed the study, conducted datacollection, and drafted the initial manuscript; Dr Gorelickconceptualized and designed the study, aided in data collection,and revised and reviewed the initial manuscript; Drs Hoffmannand Li carried out the initial analyses, and reviewed and revisedthe manuscript; and all authors approved the final manuscriptas submitted.

Please note that Dr Li is no longer employed at the MedicalCollege of Wisconsin. She is now affiliated with UnitedHealthcare Group. The change in affiliation occurred afteranalysis of the results was completed.

www.pediatrics.org/cgi/doi/10.1542/peds.2013-3102

doi:10.1542/peds.2013-3102

Accepted for publication Apr 7, 2014

Address correspondence to Matthew Gray, MD, Department ofPediatrics, Medical College of Wisconsin, 999 North 92nd St,Milwaukee, WI 53226. E-mail: mgray@mcw.edu.

PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).

Copyright © 2014 by the American Academy of Pediatrics

FINANCIAL DISCLOSURE: The authors have indicated they haveno financial relationships relevant to this article to disclose.

FUNDING: No external funding.

POTENTIAL CONFLICT OF INTEREST: The authors have indicatedthey have no potential conflicts of interest to disclose.

110 GRAY et al

mailto:mgray@mcw.edu

Intussusception is a common cause ofabdominal pain and intestinal ob-struction in the pediatric population.Since 2000, annual hospitalization ratesfor intussusception in the United Stateshave remained steady at approximately35 cases per 100 000 infants, and are ashigh as 62 per 100 000 infants 26 to 29weeks of age.1 Currently, the man-agement of intussusception remainsvariable; however, there has been asignificant trend away from surgicalreduction toward enema reduction.1,2

Despite a growing body of literaturesupporting outpatient management ofpatients with successful enema re-duction, it is still common practice tohospitalize patients for 24 to 48 hoursof observation.3–6 This is based onhistorical recommendations foundedon the concerns for recurrence andpostreduction complications.7

A body of evidence has emerged sug-gesting that the rate of significantcomplications, specifically perforation,post enema reduction is very low. Aspart of their review of intussusceptionmanagement, Daneman and Navarro2

reported rates of perforation between0% and 5.9%, with the vast majority ofseries reporting rates ,1%. Reportedrecurrence rates, however, are highlyvariable, are not calculated in a stan-dardized manner, and most are basedon relatively small trials. In addition,many of the reported recurrences oc-curred.48 to 72 hours postreduction.Consequently, management recommen-dations would be best based on a pre-cise understanding of the risk of early(within 24–48 hours) recurrence for anindividual patient.

The aim of our study was to performa systematic review of the existing lit-eraturetoestimateoverall, 24-hour,and48-hour recurrence rates post enemareduction inchildrenwitharadiographicdiagnosis of ileocolic intussusceptionin an effort to pose suggested recom-mendations for clinical practice.

METHODS

Data Sources and Searches

We performed electronic searches ofPubMed, the Cochrane Database, andOVID Medline from 1966 to the end ofDecember 2011. The search included thefollowing keywords: intussusception, re-currence, and enema (Supplemental Ta-ble 5). A prevalidated filter to limit thesearch to children was also used.8 Thesearch was limited to human studies andpublications in English. Hand searches ofthe bibliographies of all articles identi-fied in the initial online search werecompleted to identify further articles forfinal inclusion. Authors were contactedif studies quoted a recurrence rate butdid not define the numerator or de-nominator needed to calculate this rate.

Study Selection

Studies were included if they met allof the following criteria: (1) included

patients age 0 to 18 years; (2) intus-susception was radiographically pro-ven and reduced by enema; and (3) thenumberof intussusceptions reducedbyenema and the number of recurrenceswas provided or could be calculated.Two reviewers (M.P.G. and M.H.G.) in-dependently evaluated titles and ab-stracts of articles retrieved from theinitial search. A list of relevant articleswascreated, agreedonbybothauthors,and retrieved in full. Both authors(M.P.G. and M.H.G.) reviewed all full-textarticles independently for final in-clusion and disagreements were rec-onciled by consensus.

Data Extraction

Data were extracted onto a prefor-matted data sheet by the primary au-thor (M.P.G.). Thesecondauthor(M.H.G.)audited 10% of the articles included toensure concordance. Outcomemeasures

FIGURE 1Study selection for the meta-analysis.

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TABLE 1 Characteristics of Studies Included in the Meta-analysis

Study (Year) Setting n QualityScore

Age, mo % Male EnemaType

Outcomes OverallRecurrenceRate, %

Adekunle-Ojo et al (2011)21 United States 149 5 3–95 56 CE TotR 12.5Beasley et al (1987)22 Australia 602 5 Undefined 64 CE TotR 8.9Bonadio (1988)23 United States 88 6 2–36 62 CE 24 h, 48 h, TotR 2.1Champoux et al (1994)24 United States 263 7 1–174 62 CE 24 h, TotR 13.2Chung et al (1994)25 China 333 5 1–180 61.6 CE TotR 11.6Collins et al (1989)26 United States 58 5 3–72 64 CE TotR 10.4Courtney et al (1981)27 Ireland 56 5 1–120 61 CE 24 h, 48 h, TotR 5.0Crankson et al (2003)28 Saudi Arabia 33 7 0–36 64 CE TotR 31.3Crystal et al (2002)29 Israel 83 8 2–54 58 CE 48 h, TotR 14.3Daneman et al (1998)18 Canada 262 8 Undefined Undefined CE 48 h, TotR 11.1Dawod and Osundwa (1992)30 Qatar 67 7 2–24 72 CE TotR 9.1Denenholz and Feher (1955)31 United States 29 5 5–32 Undefined CE 24 h, 48 h, TotR 0.0Eshel et al (1997)32 Israel 58 7 1–20 68 CE 24 h, 48 h, TotR 14.7Fecteau et al (1996)17 Canada 258 7 1–20 Undefined CE TotR 12.5Freund et al (1977)33 Israel 49 5 1–108 65 CE TotR 5.6Goon Hong (1986)34 Malaysia 8 3 1–60 100 CE 24 h, 48 h, TotR 0.0Hadidi and El Shal(1999)14 Egypt 50 10 Undefined 66 CE 24 h, 48 h, TotR 0.0Hiller (1955)35 Australia 60 5 Undefined Undefined CE 24 h, 48 h, TotR 8.3Kaushal (1972)36 England 87 4 Undefined Undefined CE TotR 17.9Kellog et al (1961)37 United Kingdom 80 5 0–96 56 CE TotR 14.8Kim and Rhu (1989)38 Korea 385 6 1–72 69 CE 24 h, 48 h, TotR 9.5Korttila (1952)39 Finland 33 3 3.5–132 64 CE 24 h, 48 h, TotR 28.6Krasna et al (1990)40 United States 56 6 Undefined Undefined CE 24 h, 48 h, TotR 0.0Le Masne et al (1999)41 France 113 7 0–108 62 CE 24 h, 48 h, TotR 13.0Liu et al (1986)42 Ireland 66 5 1–28 70 CE 24 h, 48 h, TotR 8.9MacKay et al (1987)43 Australia 91 5 2–48 60 CE TotR 17.1Meyer et al (1993)44 United States 27 10 Undefined 67 CE 24 h, 48 h, TotR 11.8Minami and Fujii (1975)45 Japan 104 5 2–22 67 CE 24 h, 48 h, TotR 9.6Nordshus and Swensen (1979)46 Norway 108 9 0–147 66 CE TotR 25.0Okuyama et al (1999)47 Japan 104 6 1–83 56 CE TotR 7.2Packard (1955)48 United States 89 3 Undefined Undefined CE TotR 10.0Paes et al (1988)49 United Kingdom 89 5 Undefined Undefined CE 24 h, 48 h, TotR 17.1Palder et al (1991)50 Canada 100 7 3–167 45 CE TotR 13.2Ravitch (1958)51 United States 199 3 Undefined Undefined CE TotR 5.7Reid et al (2001)52 New Zealand 34 5 Undefined Undefined CE TotR 9.1Riebel et al (1993)53 Germany 41 5 3–105 68 CE TotR 12.1Shehata et al (2000)54 Egypt 50 3 Undefined Undefined CE TotR 9.7Simon et al (1994)55 Australia 20 7 2.5–17 60 CE 24 h, 48 h, TotR 0.0Skipper et al (1990)56 United States 157 7 Undefined 68 CE TotR 20.7Tangi et al (1991)57 Wales 119 5 Undefined Undefined CE TotR 10.9van den Ende et al (2005)58 Netherlands 113 10 Undefined 60 CE 24 h, 48 h, TotR 11.7Wayne et al (1973)59 United States 344 5 0.5–216 66 CE 48 h, TotR 6.9West et al (1987)60 United States 83 6 2–264 61 CE TotR 29.4Winstanley et al (1987)61 United Kingdom 75 7 0–36 Undefined CE 24 h, 48 h, TotR 7.4Yang (2001)62 Taiwan 89 10 0–180 74 CE 24 h, 48 h, TotR 14.5Bai et al (2006)63 China 5218 5 2–216 67.4 UGNCE TotR 5.6Chan et al (1997)64 China 26 5 Undefined 43 UGNCE TotR 9.1Choi et al (1994)65 Korea 115 7 2–60 71 UGNCE TotR 6.5Essa et al (2011)66 Egypt 75 10 5–24 79 UGNCE 24 h, 48 h, TotR 10.0Gonzalez-Spinola et al (1999)67 Spain 176 5 2–108 59 UGNCE 48 h, TotR 10.0Hadidi and El Shal(1999)14 Egypt 47 10 Undefined 62 UGNCE 24 h, 48 h, TotR 0.0Krishnakumar et al (2006)68 India 25 4 4–48 64 UGNCE 24 h, 48 h, TotR 4.2Rohrschneider and Troger(1995)69

Germany 40 5 3.5–52 60 UGNCE TotR 16.7

Shehata et al (2000)54 Egypt 840 3 Undefined Undefined UGNCE TotR 6.9Al-Jazaeri et al (2006)3 Canada 121 7 5–133 71 FGAE TotR 13.8Daneman et al (1998)18 Canada 501 8 Undefined Undefined FGAE 48 h, TotR 8.0Eshel et al (1997)32 Israel 35 7 1–20 68 FGAE 24 h, 48 h, TotR 3.3Fragoso et al (2007)70 Portugal 164 10 Undefined 72 FGAE TotR 6.5Gu et al (2000)71 China 199 3 3.5–120 59 FGAE 24 h, 48 h, TotR 14.1

112 GRAY et al

included the number of successfulreductions and the total number ofrecurrences. When datawere available,the number of recurrences occurring,24 hours post reduction and ,48hours post reduction was recordedseparately. For articles reporting bothenema-reduced and operatively re-duced intussusceptions, only dataon those reduced by enema wereincluded.

Factors that were believed to affectrecurrence rates also were recorded.These included the type of enemaperformed (contrast enema [CE],fluoroscopy-guided air enema [FGAE],ultrasound-guided noncontrast enema[UGNCE]), year of publication, andcountry in which the study was con-ducted. Study locationwasstratified into“Developed” and “Developing” countriesbased on United Nations Children’s Funddefinitions of industrialized countries,with “Developed” defined as the UnitedStates, England, Finland, France, Ireland,Israel, Germany, the Netherlands, Nor-way, Portugal, Scotland, Spain, theUnited Kingdom, Australia, Japan, andNew Zealand.9

Quality Assessment

It has been shown that the quality ofreporting is associated with the method-ological quality of clinical trials; however,there are currently no validated scalesto assess the quality of observationalstudies.10,11 Most studies included in ourmeta-analysis are observational; there-fore, we chose to evaluate the method-ological quality of the studies includedin this review and meta-analysis usinga scale we developed. Studies wereassigned a score of 0 to 2 for each ofthe following criteria (the criteria forassigning 0, 1, or 2 points are indicatedrespectively in parentheses):

1. Enrollment (not specified, non-consecutive, consecutive);

2. Design (not specified, retrospective,prospective).

Studies were then assigned a score of 1to 3 for eachof the following criteria (thecriteria for assigning 1, 2, or 3 points areindicated respectively in parentheses):

1. Definition of data source (not spec-ified, specific but general mentionof data source, eg, “medical recordswere reviewed,” specifically defined,eg, “inpatient and radiology recordswere reviewed”);

2. Data abstraction (not specified, spe-cific mention of data to be extractedbut not method of abstraction, spe-cific mention of what data and howit was abstracted).

We made note of follow-up (retrospec-tive versus prospective) when possible,and found little variance. Most studieshad retrospective follow-up. As such,we did not include “follow-up” in our

TABLE 1 Continued

Study (Year) Setting n QualityScore

Age, mo % Male EnemaType

Outcomes OverallRecurrenceRate, %

Hadidi and El Shal (1999)14 Egypt 50 10 Undefined 62 FGAE 24 h, 48 h, TotR 0.0Herwig et al (2009)5 United States 124 8 2–135 71 FGAE 24 h, 48 h, TotR 6.7Katz et al (1993)72 Australia 255 10 1–96 76 FGAE TotR 10.1Lehnert et al (2009)73 Germany 98 7 2–144 61 FGAE 24 h, 48 h, TotR 6.1Lui et al (2001)74 Taiwan 194 7 1–60 58 FGAE TotR 6.6McDermott et al (1994)75 Scotland 54 8 2.5–52 59 FGAE TotR 15.8Mensah et al (2011)76 Ghana 18 9 0–18 67 FGAE 24 h, 48 h, TotR 0.0Meyer et al (1993)44 United States 25 10 Undefined 67 FGAE 24 h, 48 h, TotR 5.3Palder et al (1991)50 Canada 100 7 2–96 62 FGAE TotR 5.3Reid et al (2001)52 New Zealand 42 5 Undefined Undefined FGAE TotR 6.1Renwick et al (1992)77 Australia 187 10 Undefined Undefined FGAE TotR 7.9Rubi et al (2002)78 Spain 21 5 2–144 55 FGAE TotR 4.8Stringer and Ein (1990)19 Canada 364 5 0–96 Undefined FGAE TotR 10.7Tamahana et al (1987)79 Japan 222 5 1–84 72 FGAE TotR 6.6Tangi et al (1991)57 Wales 11 5 Undefined Undefined FGAE 24 h, 48 h, TotR 0.0Tareen et al 201180 Ireland 256 5 0–144 70 FGAE TotR 15.8Todani et al (1990)81 Japan 137 5 Undefined Undefined FGAE TotR 8.7Wang et al (1995)82 China 224 5 1.5–48 72 FGAE 24 h, 48 h, TotR 1.4Yoon et al (2001)83 South Korea 49 9 2–84 73 FGAE 24 h, 48 h, TotR 6.7

24 h, 24-hour recurrence rate; 48 h, 48-hour recurrence rate; TotR, total recurrence rate.

TABLE 2 Pooled Recurrence Rates by Enema Modality

EnemaModality

Pooled Recurrence Rate, % (95% CI) I2, %

Overall 48-h 24-h Overall 48-h 24-h

CE 12.7 (11.1–14.4) 5.4 (3.7–7.8) 3.9 (2.2–6.7) 28.8 32.3 47.0UGNCE 7.5 (5.7–9.8) 6.6 (4.0–10.7) 3.9 (1.5–10.1) 52.4 0.0 0.0FGAE 8.5 (6.9–10.4) 2.7 (1.2–6.5) 2.2 (0.7–6.5) 50.1 73.8 59.8

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quality score. Total net scores couldrange from 2 to 10, with higher scoresindicating higher quality. Both authors(M.P.G. and M.H.G.) independently as-signed the quality scores for eachstudy and differences were reconciledby mutual agreement. k for interrateragreement was calculated.

Data Analysis

Recurrence rates were calculated ina standardized manner for each study

by dividing the total number of patientswith recurrence by the total number ofpatients with a successful reduction.Patients with .1 recurrence werecounted only once. Heterogeneity be-tween studies was identified by usinga x2 test and quantified with the I2

statistic.12 Meta-analysis was perfor-med by using a random effects modelbased on the method of DerSimonianand Laird.13 To account for the numberof zero proportions in this study, the

log-transformed proportion was usedto calculate confidence intervals thatwould be non-negative. The analysiswas stratified based on enema type.Meta-regression was performed toidentify potential sources of heteroge-neity. We planned a priori to assess forsources of heterogeneity, includingquality score, the year of study com-pletion, and study location. In post hocanalysis, estimated median age wasincluded in the meta-regression. Thevast majority of studies reported onlyan age range. As such, median age wasestimated by the midpoint and square-root transformation of the midpoint.Both variables were tested in the re-gression analysis. For the primaryoutcome, recurrence rates by enemamodalities, a P value of .05 was used.For the secondary analyses comparingdifferent time frames and covariates,a P , .01 was used to account formultiple testing of the secondary out-comes. R 2.13 (R Foundation for Sta-tistical Computing, Vienna, Austria)and Stata 11.2 (Stata Corp, CollegeStation, TX) were used for this analysis.

RESULTS

Description of Articles

The described search strategies iden-tified 325 articles and abstracts (Fig 1).Of these, 154 were excluded based ontheir title or abstract, and 167 wereretrieved in full. Sixty-nine articles metfull inclusion criteria and were in-cluded in the meta-analysis (Table 1).Ninety-eight articles were excludedarter review of the full text (Supple-mental Table 4).

The studies included were drawn froma wide body of literature includinggeneralpediatric, emergencymedicine,and radiology journals. The qualityscores for the 69 included studies werewidely variable and ranged from2 to 10;however, interrater reliability for qualityscoreswas excellent (k = 0.93). Fifty-fiveof these articles were retrospective

FIGURE 2Overall recurrence rates by enema modality.

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studies and 49 of them had consecutiveenrollment. One study was a random-ized controlled study.14 The studies in-cluded were conducted in 28 differentcountries, with 13 studies conducted inthe United States. The ages of studyparticipants ranged from,1 month to22 years.

Recurrence Rates

When estimating pooled recurrencerates across all studies, independent ofenema modality, we found that theresults were highly heterogeneoussignifying that effect sizes varied be-tween studies and enemamodality. Theoverall results were heavily biased to-wardcontrast enemareduction, largelydue to the substantial difference in thenumber of studies included for eachenema modality (46 CE, 9 UGNCE, 24FGAE). Although to some extent thenumber of subjects adjusts for this(5362 subjects with CE vs 10 013 sub-jects with FGAE or UGNCE), it is notenough to fully account for the bias.Because the results for individual en-ema modalities are not subject to thisbias, subsequent analyses were strat-ified by modality.

Recurrence rates are reported by mo-dality in Table 2. Overall recurrencerates were 12.7% (95% confidence in-terval [CI] 11.1%–14.4%, I2 = 28.8%) forCE, 7.5% (95% CI 5.7%–9.8%, I2 = 52.4%)for UGNCE, and 8.5% (95% CI 6.9%–10.4%, I2 = 50.1%) for FGAE (Fig 2). Therecurrence rates at 24 hours and 48hours were low. Recurrence rateswithin 24 hours post reduction were3.9% (95% CI 2.2%–6.7%, I2 = 47.0%) forCE, 3.9% (95% CI 1.5%–10.1%, I2 = 0.0%)for UGNCE, and 2.2% (95% CI 0.7%–6.5%, I2 = 59.8%) for FGAE (Fig 3). Re-currence rates within 48 hours postreduction were 5.4% (95% CI 3.7%–7.8%, I2 = 32.3%) for CE, 6.6% (95% CI4.0%–10.7%, I2 = 0.0%) for UGNCE, and2.7% (95% CI 1.2%–6.5%, I2 = 73.8%) forFGAE (Fig 4).

Sensitivity Analyses

Heterogeneity was found when com-bining studies by enema modality (Ta-ble 2). A study by Higgins et al15

suggests that I2 values from 0% to 50%represent a low to moderate amount ofheterogeneity. Meta-regression wasconducted to identify potential sourcesof heterogeneity. Enema modality wasa significant source of heterogeneity(P = .002 FGAE, P = .028 UGNCE, P = .151CE) for overall recurrence rates. Enemamodality, however, was not a significantsource of heterogeneity for 48-hour

(P = .461 CE, P = .706 UGNCE, P = .515FGAE) or 24-hour recurrence rates(P = .471 CE, P = .702 UGNCE, P = .661FGAE). Study quality, year of studypublication, and country of origin werenot found to be significant sources ofheterogeneity for overall, 48-hour, or24-hour recurrence rates. In post hocregression analysis, estimated medianage was not found to be significant foroverall, 24-hour, or 48-hour recurrencerates.

Because the study by Bai et al63 ac-counted for nearly one-third of the

FIGURE 3The 24-hour recurrence rates by enema modality.

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patients included in the overall re-currence rate data for UGNCE, weconducted a weighted meta-regressionto estimate the effect of each method.

Pooled estimates including the studyby Bai et al63 were compared withpooled estimates excluding this study(Table 3). Inclusion of the study by

Bai et al63 had minimal effect on thepooled estimate.

Learning effect was assessed by ex-amining results by year. A significanttrend was identified for quality score.Quality scores showed a significanttrend (even using the multiple testingadjustment) with year (Spearman r =0.504, P = .0004) for CE only. If studiesare restricted to 1980 and later, thereis no correlation between quality scoresand year of publication (SupplementalTable 6). Of note, all studies of noncon-trast reductions were published after1980. The Begg test for publication biaswas used and did not demonstrate biasfor any of the outcome variables.

DISCUSSION

This meta-analysis of published studiesdemonstrates that an individual’s riskof having an early (within 24 to 48hours) recurrent intussusception aftera successful enema reduction is low. Inaddition, the risk of recurrence is in-dependent of enema type, study loca-tion, year of study completion, andstudy quality. The risk of recurrence inthe first 24 hours post reduction is2.2% to 3.9% and 2.7% to 6.6% in thefirst 48 hours. Assuming a 24-hour re-currence risk of 3.9%, it would requirehospitalizing 26 patients for 24 hoursto identify a single recurrence.

This suggests that the vast majorityof recurrences will not be identified byovernight hospitalization. In addition,recurrent intussusceptions canbe safelyand successfully reduced via repeat en-ema, and significant complications as-sociated with enema reduction are rare.Multiple studies supporting outpatientmanagement after successful enemareduction have demonstrated high ratesof success with repeat enema reductionwithout delayed complications.16–20 Intheir series of 1340 patients, Niramiset al20 reported success rates as high as96% with barium enema and 92% withair enema.

FIGURE 4The 48-hour recurrence rates by enema modality.

TABLE 3 Effect of Study Size on Overall Recurrence Rate

Recurrence Rate,% (95% CI)

P Value (ComparedWith CE)

All studies, n = 16 178CE 10.455 (9.00–11.91)FGAE 6.984 (4.51–9.45) .018UGNCE 7.038 (5.49–8.58) .002

Excluding Bai et al,63 n = 11 050CE 10.467 (9.1–11.93)FGAE 7.466 (4.57–10.56) .069UGNCE 7.049 (5.48–8.61) .002

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There are several limitations to ourstudy. First, because of the relative in-frequency with which intussusceptionoccurs, most of the studies included inthis meta-analysis are retrospectivestudies. Many are small, and they varywidely in quality. As such, we attemptedtomeasureandcontrol for thequalityofreporting for each study. Second, thestudies differ in both known features,such as enema reduction technique orsetting, and possibly unknown featuresthat we were unable to measure. Asthese differences were expected, weused random effects modeling in ouranalyses, adjusting for the suspected

confounders and providing more con-servative estimates of confidence lim-its. Finally, the number of studiesreporting the specific timing of recur-rences was limited.

Despite these limitations, our studyimproves the understanding of the riskof early (within 24 to 48 hours) re-currence for an individual patient, andstrongly suggests that that risk is low. Incombination with the knowledge thatserious postreduction complicationsare rare and that recurrences can besafely and successfully managed non-operatively, it is reasonable to suggestthat outpatient management in an

appropriately selected population ofwell-appearing patients would beappropriate. In addition to the riskof recurrence, providers need toconsider clinical factors, such as easeof reduction, number of reductionattempts, and a patient’s hemody-namic status pre- and postreductionwhen making disposition decisions.Consistent with other recently pub-lished studies, our results supportthe development of multidisciplinaryguidelines for the appropriate outpa-tient management of those asymptom-atic patients who have had successfulenema reduction.

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THE NEW LIBRARY: A few weeks ago, my wife and I went downtown to the PublicLibrary to hear a talk. Amazingly, the place was packed. I have been in libraries ofvarious sizes over the past year: the small Charlotte, VT library, the huge New YorkCity Library, and the medium sized Burlington Library. All were humming withactivity. A few years ago, many predicted the demise of the public library citingthe rise of the internet, e-readers, and social media. However, libraries have beenbusy re-inventing themselves and not only have staved off extinction but arethriving. As reported in The New York Times (U.S.: March 7, 2014), physical visits tolibraries are off the charts. For example, the Boston Public Library had an almost50% increase in the number of visitors in 2012 to more than 1.7 million. My soncan borrow movies, physical books, and electronic books from the BurlingtonLibrary. Some libraries offer access to 3-D printers, laser cutters, and millingmachines, while others lend out musical instruments or plots of land on which topractice organic farming. Many are trying to lure visitors with wide open spaces,lobbies, and even food courts. I see people eating in libraries all the time – whichwhen I was a child would have led to automatic dismissal and revocation of mylibrary card.Librarians too have different jobs. Rather than answering single questions, theymay act as information navigators to help customers sift through many, manyanswers. While some libraries have gone completely digital – meaning that nobooks are present at all – all-digital libraries have not been entirely successfuland have often brought back books. The reason is that while almost a third ofAmericans read e-books, in 2012 less than 5% read e-books only. I for one amthrilled with the change. I like the fact there are still large tables and comfychairs, but now there are food courts, computers, internet access, and all kindsof activities that appeal to not only my parents and I, but my children as well.

Noted by WVR, MD

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