International Journal of Gynecology and Obstetrics 115 (2011) 5–10

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International Journal of Gynecology and Obstetrics

j ourna l homepage: www.e lsev ie r.com/ locate / i jgo

REVIEW ARTICLE

Single- versus double-layer closure of the hysterotomy incision during cesareandelivery and risk of uterine rupture

Stéphanie Roberge a,b, Nils Chaillet c, Amélie Boutin a,b, Lynne Moore b,d, Nicole Jastrow e,Normand Brassard a, Robert J. Gauthier c, Igor Hudic f, Thomas D. Shipp g, Charlotte H.E. Weimar h,Zlatan Fatusic f, Suzanne Demers a, Emmanuel Bujold a,b,⁎a Department of Obstetrics and Gynecology, Faculty of Medicine, Université Laval, Quebec, Canadab Department of Social and Preventive Medicine, Faculty of Medicine, Université Laval, Quebec, Canadac Department of Obstetrics and Gynecology, Faculty of Medicine, Université de Montréal, Montreal, Canadad Centre Hospitalier Affilié Universitaire de Québec, Hôpital Enfant-Jésus, Quebec, Canadae Department of Obstetrics and Gynecology, Faculty of Medicine, Hôpitaux Universitaire de Genève, Université de Genève, Geneva, Switzerlandf Clinic of Gynecology and Obstetrics, University Clinical Center, Tuzla, Bosnia and Herzegovinag Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Harvard Medical School, Boston, USAh Department of Obstetrics and Gynecology, University Medical Centre Utrecht, Utrecht, The Netherlands

⁎ Corresponding author at: Maternal-Fetal Medicine,Gynecology and Department of Social and Preventive MUniversité Laval, 2705, boulevard Laurier, Quebec, QC, C933 6872; fax: +1 418 577 2024.

E-mail address: emmanuel.bujold@crchul.ulaval.ca (

0020-7292/$ – see front matter © 2011 International Feddoi:10.1016/j.ijgo.2011.04.013

a b s t r a c t

a r t i c l e i n f o

Article history:

Received 23 December 2010Received in revised form 17 April 2011Accepted 27 June 2011

Keywords:Cesarean deliveryHysterotomyPregnancyUterine ruptureVaginal birth after cesarean

Objective: To evaluate the best available evidence regarding the association between single-layer closure anduterine rupture. Methods: The PubMed, Embase, and Cochrane Central Register of Controlled Trials databaseswere searched for relevant observational and experimental studies that included women with a previoussingle, low, transverse cesarean delivery who had attempted a trial of labor (TOL). The risks of uterine ruptureand uterine dehiscence were assessed by pooled odds ratios (OR) calculated with a random effects model.Results: Nine studies including 5810 women were reviewed. Overall, the risk of uterine rupture during TOLafter a single-layer closure was not significantly different from that after a double-layer closure (OR 1.71; 95%confidence interval [CI] 0.66–4.44). However, a sensitivity analysis indicated that the risk of uterine rupturewas increased after a locked single-layer closure (OR 4.96; 95% CI 2.58–9.52, Pb0.001) but not after anunlocked single-layer closure (OR 0.49; 95% CI 0.21–1.16), compared with a double-layer closure. Conclusion:

Locked but not unlocked single-layer closures were associated with a higher uterine rupture risk than double-layer closure in women attempting a TOL.© 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

1. Introduction

Cesarean delivery is one of the most frequent surgical proceduresperformed worldwide, but for some technical aspects of thisprocedure a standard or consensus is still lacking [1,2]. Closure ofthe hysterotomy site is an aspect that has gained interest because ofthe potential relationship with uterine rupture during a trial of labor(TOL) in future pregnancies [3]. Uterine rupture, one of the worstobstetrical complications, is associated with significant neonatal andmaternal morbidity [4,5].

Several techniques for myometrium closure have been described,including the use of interrupted, locked, and unlocked continuoussutures with single- or double-layer closure [1,6]. Single-layer locked,

Department of Obstetrics andedicine, Faculty of Medicine,anada G1V 4G2. Tel.: +1 418

E. Bujold).

eration of Gynecology and Obstetrics

continuous suturing, popularized in North America during the late1980s, is part of the Misgav–Ladach technique developed by Stark andcolleagues [7,8]. Single-layer as opposed to double-layer closure hasbeen shown to reduce operating time and blood loss [3]. However, avery large randomized controlled trial (RCT) [9] did not find suchbenefits, and long-term follow-up of these patients is currentlylacking. Recent data indicate that single-layer closure may be one ofthe most important factors related to uterine rupture [10,11].Therefore, a systematic review and a meta-analysis were performedto compare the impact of single- versus double-layer closure onuterine rupture risk.

2. Methods

Medical subject headings and text words served to generate thekey words “uterus”, “uterine”, “dehiscence”, “rupture”, “separation”,“scar”, “VBAC”, “vaginal birth after cesarean”, “closure”, “caesarean”,and “cesarean”. These key words were combined to search theelectronic databases PubMed, Embase, and Cochrane Central Register

. Published by Elsevier Ireland Ltd. All rights reserved.

6 S. Roberge et al. / International Journal of Gynecology and Obstetrics 115 (2011) 5–10

of Controlled Trials for relevant citations published between January1, 1954, and December 31, 2010 (PubMed), January 1, 1966, andDecember 31, 2010 (Embase), and January 1, 1965, and December 31,2010 (Cochrane Central Register of Controlled Trials). Additionalstudies were identified from the bibliographies of Cochrane system-atic reviews on uterine closure at the time of cesarean delivery. Nolanguage restriction was applied.

All citations were screened by 2 reviewers (S.R., A.B.). Theabstracts of citations that seemed to be relevant were reviewed by 2independent reviewers (S.R., E.B.), and all potentially relevant studies(according to the study inclusion criteria) were retrieved for anindependent review of the full article by both reviewers. Disagree-ments were resolved by discussion and third party judgment, ifwarranted. To ensure the quality of the meta-analysis, the guidelinesof the Meta-analysis of Observational Studies in Epidemiology groupwere followed [12]. Data were extracted twice independently andcompiled by article title, year, numerical data, study design, andquality. Primary or corresponding authors were contacted foradditional information when necessary.

The present report included cohort studies, case–control studies,and RCT that comprised women with a previous single, low,transverse cesarean delivery who underwent TOL. Studies involvingwomen with more than 1 previous cesarean delivery were excludedfrom the final analysis if data on women with a single previouscesarean delivery could not be obtained from the authors. Because ofthe lack of available RCT, high-quality case–control and cohort studieswere included in the meta-analysis according to criteria developed bythe Cochrane Effective Practice and Organisation of Care Group[13,14]. The quality of the observational studies was evaluated on thebasis of the Newcastle–Ottawa Scale (maximum score of 9 points) forassessing the quality of nonrandomized studies in meta-analyses [15].

Potentially relevant citations identified and screened for research (n=1964)

Trials retrieved for more detailed evaluation (n=52)

Trials considered in the analysis (n=12)

1 Randomized controlled trial

6 Cohort studies

2 Case–cstudie

Fig. 1. Summary of the

Studies scoring less than 5 points were considered to be of low qualityand were excluded from the analysis.

All studies that compared single-layer with double-layer closure ofthe myometrium were included. The primary outcome was uterinerupture, defined as a complete separation of the uterine scar withdisruption of the visceral peritoneum or rupture of the bladder,necessitating an emergency intervention (or an equivalent definition).Secondary outcomes were: (1) Uterine scar separation, includinguterine rupture and asymptomatic uterine scar dehiscence, diagnosedat the time of laparotomy after a TOL; uterine scar dehiscence wasdefined as a partial opening of the uterus with an intact visceralperitoneum (or an equivalent definition); and (2) uterine scarseparation diagnosed at the time of an elective repeat cesarean(ERC) delivery. The 2 outcomes were separated because labor mightstretch the lower uterine segment and influence the rate of uterinescar defects. Trials that did not compare the 2 types of hysterotomyclosure at cesarean delivery for at least 1 outcome of interest wereexcluded from the review.

The risks associated with single- and double-layer closure werecompared for each outcomebymeans of odds ratios (OR)with their 95%confidence intervals (CI), calculated individually according to theMantel–Haenszel method and weighted for each study. DerSimonianand Laird random effects models were used to calculate pooled OR [16].Random effects were applied to avoid bias in the pooled estimatesbecause of variation between studies [16]. The analyseswere performedwith Review Manager 5.0.12 (The Nordic Cochrane Centre, TheCochrane Collaboration, Copenhagen, Denmark) software. The I2

statistic was computed to assess the heterogeneity of data; theheterogeneity was considered to be elevated if I2 was more than 50%[17]. Sensitivity analyses were performed according to the Cochranecriteria [13] to evaluate the impact of heterogeneity and the robustness

Studies excluded because they included women with more than 1 previous cesarean delivery with nodata available for those who had 1 cesarean delivery only (n=3)

Irrelevant citations excluded on the basis of title and abstract (n=1912)

Letters (editorials, comments, etc.)Case-reportsReviews/meta-analyses/recommendationsDifferent subjectOlder than 1965

Full articles excluded (n=40)

Letters (editorials, comments, etc.)Reviews or meta-analyses Recommendations (practice guideline, etc) Different comparison or interventionDifferent subject

ontrol s

•••

••

•••

••

selection process.

Suture

material

Chromic

catgut

Chromic

catgut

Chromic

catgut

Polyglactin91

0

Chromic

catgut

Polyglecap

ronde

laye

dab

sorbab

lemon

ofilamen

t

Chromic

catgut

Chromic

catgut

and

polyglyc

olic

acid

Chromic

catgut

and

polyglactin91

0

7S. Roberge et al. / International Journal of Gynecology and Obstetrics 115 (2011) 5–10

of the results [18–20]. For this purpose, subgroup analyses wereconducted according to trial type (RCT, case–control study, cohortstudy), trial size, type of single-layer closure (locked or unlocked), TOLperiod (up to 2002 or after 2002), region (Europe or North America),and inclusion/exclusion of women with more than 1 previous cesareandelivery. A subgroup analysis based on the type of double-layer closurewas not possible because standards for double-layer closure wereabsent in most centers.

Table1

Characteristicsof

includ

edstud

ies.

Firstau

thor

and

year

ofpu

blication

Type

ofstud

yLo

cation

Stud

ype

riod

Participan

tch

aracteristics

Type

ofclosure

Gestation

alag

eat

deliv

ery

Wom

enwithmultiple

gestations

includ

edIndu

ctionof

labo

rallowed

Wom

enwitha

prev

ious

vagina

lde

liveryinclud

ed

Sing

lelaye

rDou

blelaye

r

Bujold

2009

Prospe

ctiveco

hort

stud

ySte-JustineHospital,

Mon

trea

l,Ca

nada

2004

–20

06≥36

wee

ksNo

Yes

Yes

Lock

edNot

specified

Bujold

2010

Case–co

ntrols

tudy

10centersin

Mon

trea

larea

,Can

ada

1992

–20

02≥24

wee

ksYe

sYe

sYe

sLo

cked

Not

specified

Chap

man

1997

Rand

omized

controlle

dtrial

Birm

ingh

am,A

L,USA

1989

–19

91≥18

wee

ksNo

Yes

Yes

Lock

edFirstlaye

rlock

ed

Durnw

ald20

03Re

trospe

ctiveco

hort

stud

yMetroHea

lthMed

ical

Center,O

H,U

SA19

89–20

01≥24

wee

ksNo

Yes

No

Unloc

ked

Imbricatinglaye

rap

pliedov

erthefirstlaye

rGya

mfi20

06Re

trospe

ctiveco

hort

stud

yMou

ntSina

iSch

oolo

fMed

icine,

New

-York

City,N

Y,USA

1996

–20

00≥37

wee

ksNo

Yes

Yes

Lock

edNot

specified

Hud

ić20

10Re

trospe

ctiveco

hort

stud

yUnive

rsityClinical

Centre,T

uzla,B

osnia

andHerze

govina

2002

–20

08≥37

wee

ksNo

No

Yes

Unloc

ked

Not

specified

Jastrow

2010

Retrospe

ctiveco

hort

stud

ySte-JustineHospital,

Mon

trea

l,Ca

nada

1987

–20

04≥24

wee

ksNo

Yes

Yes

Lock

edNot

specified

Rao20

03Re

trospe

ctiveco

hort

stud

yNishtar

Hospital,

Multan,

Pakistan

1996

–20

02Not

men

tion

edYe

sNo

Not

men

tion

edUnloc

ked

Not

specified

Weimar

2010

Case–co

ntrols

tudy

38Hospitals

inTh

eNethe

rlan

ds20

02–20

03Mea

n39

.8wee

ksNo

Yes

Yes

Mostlyun

lock

edNot

specified

3. Results

The literature search identified 1964 citations, 52 of which wereselected as potentially eligible (Fig. 1). During complete review of thefull articles, 12 studies [11,21–31] were identified that compareduterine scar defects after single- versus double-layer closure.However, 3 studies [21–23] were excluded because they comprisedwomen with more than 1 previous cesarean delivery and data onwomenwith a single previous cesarean delivery could not be obtainedfrom the authors. Therefore, data from 9 studies [11,24–31] wereincluded in the meta-analysis.

The 9 studies had been published between 1988 and 2010 andconsisted of 1 RCT, 6 cohort studies, and 2 case–control studies. Theyhad been conducted in 5 countries and included 5810 women whounderwent TOL between 1987 and 2008. Data on uterine ruptureduring TOL were available for all studies; data on uterine scarseparation at the time of laparotomy after TOL were available for 6studies, and data on uterine scar separation at the time of an ERCdelivery were available for 4 studies. The studies characteristics aredetailed in Table 1. The specific technique for single-layer closure(locked versus unlocked, continuous versus interrupted) could beidentified for most studies, but many authors reported that there wasno specific standard for double-layer closure at their center. Thequality of the RCT was considered adequate and the quality of theobservational studies was good according to the Newcastle–OttawaScale [15].

The meta-analysis did not find a significantly higher overalluterine rupture risk with previous single-layer closure of the uteruscompared with double-layer closure (OR 1.71; 95% CI 0.66–4.44,P=0.27). The sensitivity analysis (Fig. 2) did not show anyheterogeneity or significant differences in the OR depending onstudy design, trial size, or study period. However, the OR differedsignificantly between studies according to the geographic area (NorthAmerica versus Europe), the type of single-layer closure (lockedversus unlocked), and the type of suture (chromic versus synthetic).Interestingly, centers using a locked single-layer closure were alsousing chromic suture, while those using an unlocked single-layerclosure were using synthetic sutures. However, within each study, thesame type of suture material was generally used for both single-layerand double-layer closures; therefore, the difference between single-and double-layer closures seen in North American studies is notattributable to suture type.

When the studies were grouped according to the technique usedfor single-layer closure (Fig. 3), a locked single-layer closure wasassociated with an increased risk of uterine rupture (OR 4.96; 95% CI2.58–9.52, Pb0.001) compared with a double-layer closure. Bycontrast, an unlocked single-layer closure was not linked with aheightened uterine rupture risk (OR 0.49; 95% CI 0.21–1.16, P=0.1).

The heterogeneity across studies was significant (I2=73%,Pb0.0002). This was mainly attributable to differences between the2 types of single-layer closure (locked single-layer closure: I2=37%,P=0.19; unlocked single-layer closure: I2=6%, P=0.36).

In additional analyses according to single-layer closure type,previous single-layer locked, continuous suturing was also associatedwith a higher risk of uterine scar separation at the time of laparotomy(OR 5.40; 95% CI 3.17–9.20, Pb0.001) compared with double-layer

Fig. 2. Sensitivity analysis. The robustness of the results was evaluated by grouping the studies according to factors that might affect the relationship between single-/double-layeruterine closure and uterine rupture risk. The dotted vertical line corresponds to the combined risk ratio from the random effects model.

8 S. Roberge et al. / International Journal of Gynecology and Obstetrics 115 (2011) 5–10

closure (Fig. 4). No difference was observed for the rate of uterine scarseparation at ERC delivery (Fig. 5).

4. Discussion

In the present meta-analysis, the risks of uterine rupture aftersingle- and double-layer closure of the uterus were not significantlydifferent. However, single-layer locked, continuous suturing wasassociated with a higher uterine rupture risk than double-layerclosure. A similar association was noted for the rate of uterine scarseparation (uterine rupture and uterine scar dehiscence) at the timeof laparotomy. By contrast, an unlocked single-layer closure was notassociatedwith a significantly higher risk of uterine rupture or uterine

Fig. 3. Meta-analysis comparing the risks of uterine rupture during a trial of labor after a prelayer closure type (locked or unlocked).

scar dehiscence than a double-layer closure. This information isimportant because cesarean delivery is a very common procedure,with more than 1 million cesarean deliveries being performed everyyear in the USA and with approximately as many women with aprevious cesarean delivery having to make a decision between an ERCdelivery and a TOL with the risk of uterine rupture [32,33].

The present findings are in agreement with a hypothesis byJelsema et al. [34], who suggested that an unlocked single-layerclosure leads to better uterine scar healing. Their view is based on thefact that locked sutures increase pressure at the suture–tissueinterface, which can cause ischemic necrosis, impairing coaptation.Meanwhile, unlocked sutures provide coaptation, hemostasis, andwound strength in the immediate postoperative period. Should the

vious single- versus double-layer uterine closure. The studies were grouped by single-

Fig. 4. Meta-analysis comparing the risks of uterine scar separation (uterine rupture or uterine scar dehiscence) after a previous single- versus double-layer uterine closure, withuterine scar separation being diagnosed during a cesarean delivery, a failed trial of labor, or a postpartum laparotomy following vaginal birth after a cesarean delivery. The studieswere grouped by single-layer closure type (locked or unlocked).

9S. Roberge et al. / International Journal of Gynecology and Obstetrics 115 (2011) 5–10

wound be exposed to additional pressure, an unlocked suture wouldprovide more strength than a locked suture. The present observationsand the hypothesis by Jelsema et al. [34] are also in agreement withthe finding of a Cochrane systematic review [3] that a single-layerclosure might have several short-term benefits, including reducedoperating time, decreased blood loss, reduced tissue disruption, andreduced introduction of foreign suture material into the wound. Mostrandomized trials in the Cochrane review [3] compared a lockedsingle-layer closure with a double-layer closure; it is thereforepossible that many benefits are related to tissue strangulation bylocked sutures, which results in better and faster hemostasis.However, few conclusions can be drawn about the short-term benefitsof locked versus unlocked single-layer closures because studiesspecifically comparing these 2 closure types are lacking [35].

The present meta-analysis has some limitations. First, most of theincluded studies were retrospective in nature. Although several RCT [3]compared the short-term outcomes after single- and double-layer

Fig. 5. Meta-analysis comparing the risks of uterine scar separation (uterine rupture or uteuterine scar separation being diagnosed during an elective repeat cesarean delivery. The st

sutures, only 1 RCT [36] provided long-term follow-up data and thesewere available for a limited number of participants only. The presentdata highlight the urgency of RCT in this area. Second, the type of single-layer closure inmost studieswasdeterminedby the authors’descriptionof standard practice at their centers. While local practice standards inmedicinearenot unusual, particularly in teachinghospitals, it is possiblethat closure techniques variedwithin somehospitals. Third, informationon the suture type (locked or unlocked) for the first or second layer of adouble-layer closurewas usually not available, but this parameter couldhave influenced the comparison between single- and double-layerclosures. Moreover, no study specifically compared locked versusunlocked single-layer sutures. Fourth, only 4 studies [26–28,31],including a total of 584 women, reported the asymptomatic dehiscencerate during ERC delivery. Unfortunately, few conclusions can be drawnfrom such small numbers. Fifth, it was not possible to evaluate thepresence of publication bias because the number of studies was toosmall to construct interpretable funnel plots. Finally, other factors such

rine scar dehiscence) after a previous single- versus double-layer uterine closure, withudies were grouped by single-layer closure type (locked or unlocked).

10 S. Roberge et al. / International Journal of Gynecology and Obstetrics 115 (2011) 5–10

as suture material, the inclusion or exclusion of decidua in the uterinesuture, and certain risk factors for uterine rupture, including fetalmacrosomia, labor dystocia, and labor induction, were not taken intoaccount. Decidua inclusion in sutures could result in a weaker scar andcould explain the difference between single-layer locked, continuousclosure and double-layer closure [37,38]. These details are not availablefrom operative reports, but they should be explored in future studies.Despite these limitations, the facts that the observational studies wererigorously selected and that the heterogeneity between studies couldmainly be explained by the type of single-layer closure attest to thevalidity of the present results. Finally, it is unlikely that previous uterineclosure would have led to changes (and, therefore, bias) in themanagement of labor because of the absence of consensus regardingthe relationship between uterine closure and uterine rupture.

In conclusion, single-layer locked, continuous suturing as opposedto a double-layer closure of the hysterotomy site may increase the riskof uterine rupture in women attempting TOL in a future pregnancy. Bycontrast, the risk of uterine rupture after an unlocked single-layerclosure seems to be comparable with that after a double-layer closure.Randomized trials with long-term follow-up are needed to comparesingle unlocked closure with double-layer (locked or unlocked first-layer) closure.

Acknowledgments

Emmanuel Bujold holds a Clinician Scientist Award and NilsChaillet holds a New Investigator Award from the Canadian Institutesof Health Research. This study was supported by the Jeanne and Jean-Louis Lévesque Perinatal Research Chair at Université Laval, Quebec,QC, Canada.

Conflict of interest

The authors have no conflicts of interest.

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