Blumenfeld Y, Caughey A, El-Sayed Y, Daniels K, Lyell D. Single- versus double-layer hysterotomy closure at primary caesarean delivery and bladder adhesions. BJOG 2010;117:690–694.

SINGLE VERSUS DOUBLE-LAYER HYSTEROTOMY CLOSUREAT PRIMARY CAESAREAN DELIVERY AND BLADDERADHESIONS

IntroductionThe frequency of primary and repeat

caesarean deliveries ↑ in USA and worldwide associated with an increased risk of placenta accreta, hysterectomy, cystotomy, bowel injury, ureteral injury, ileus, intensive care unit admission and blood transfusion

In addition increase the risk of postoperative pelvic and abdominal adhesions can increase the time required to deliver the newborn, operative blood loss and the occurrence of bladder injury

IntroductionTo reduce maternal and neonatal morbidity

studies have addressed including manual placental removal, uterine exteriorisation, subcutaneous tissue reapproximation and single- versus double-layer uterine incision closure to minimize infectious morbidity and uterine rupture.

In this study, is analysed retrospectively data from previous study to determine whether single- versus double-layer hysterotomy closure at primary caesarean delivery is associated with subsequent adhesion formation

MethodsThis study analysed a data set from a previously

reported prospective cohort study to examine the association between caesarean hysterotomy closure and pelvic adhesions.

The original study enrolled prospectively at Stanford University Medical Center from 1996 to 2003.

The data set was generated when all surgeons, were asked to complete an adhesion score sheet detailing the location and severity of adhesions

The surgeons were unaware of the purpose of the adhesion score sheet.

Methods Women were excluded from the original study if:

on record review, they were found to have had adhesions, the use of a permanent suture additional operations at first caesarean delivery postoperative wound infection or breakdown occurred following first

surgery the first operative note was unavailable intervening abdominal surgery occurred women with insulin dependent diabetes mellitus or steroid-dependent

disease The original data set included detailed information from the first and second

caesarean deliveries, labour and postoperative courses. All surgeries were performed by a resident who was supervised directly by an

attending physician. The method of surgical closure and suture material used were dependent on

the preference of the attending physician.

MethodsFor the study, patient records from the primary

caesarean delivery were reviewed again to identify whether single- or double-layer hysterotomy closure had been performed.

All participants were included in, if the hysterotomy closure could be determined from the primary caesarean operative note.

Only women who underwent a low transverse uterine incision were included in this study.

The primary outcome measure was the prevalence rate of pelvic and abdominal adhesions as reported on the adhesion score sheet at the time of repeat caesarean delivery.

MethodsAll data were entered into a Stata 7.0 (StataCorp,

College Station, TX, USA) database. Univariable statistical tests using Fisher’s exact tests

were considered to be significant with P < 0.05. Multivariable logistic regression analysis was used to

control for potential confounders, including surgical technique (closure of the parietal peritoneum, visceral peritoneum and rectus muscles), previous labour, prior peripartum infection, labour and age over 35 years.

The study was approved by the Committee on Human Research at Stanford University Medical Center.

Women were excluded from the original study if:• on record review, they were found to have had adhesions,• the use of a permanent suture• additional operations at first caesarean delivery• postoperative wound infection or breakdown occurred following first surgery• the first operative note was unavailable• intervening abdominal surgery occurred• women with insulin dependent diabetes mellitus or steroid-dependent disease

FLOW CHARTPrevious reported prospective cohort study in order to examine the

association between caesarean hysterotomy closure (single versus double layer) and pelvic adhesions

Surgeon fills an adhesion score sheet detailing the location and severity of adhesions

• All data were entered into a Stata 7.0 (StataCorp, College Station, TX, USA) database.

• Univariable statistical tests using Fisher’s exact tests were considered to be significant with P < 0.05.

• Multivariable logistic regression analysis was used to control for potential confounders

127 women were included

Single-layer hysterotomy closure 56 women (44%)

Double-layer hysterotomy closure 71 (56%)

Results127 women were included in the study

(Table 1). Single-layer hysterotomy closure at the

time of primary caesarean section was performed in 56 women (44%)

Double-layer closure was performed in 71 (56%).

There were no demographic or obstetric differences between the two groups

The mean maternal age was 29 years.

ResultsThe primary caesarean hysterotomy was

closed with chromic suture in 78% of women, and synthetic delayed absorbable suture (including dexon and vicryl) in 22%.

Primary single-layer hysterotomy closure was not associated with fascial to uterine adhesions (29% versus 20%, P = 0.29), omental to uterine adhesions (20% versus 14%, P = 0.47) or bowel adhesions (2% versus 0%, P = 0.44).

ResultsSingle-layer hysterotomy closure was associated

significantly with bladder adhesions (24% versus 7%, P = 0.01; Table 2).

The presence of bladder adhesions was determined when obstetricians specified ‘bladder’ in the ‘other’ category of the adhesion score sheet.

A multivariable logistic regression analysis of bladder adhesions was then performed (Table 3).

The odds of bladder adhesions were seven times greater with single-layer hysterotomy closure [odds ratio (OR), 6.96; 95% confidence interval (CI), 1.72–28.1] after adjusting for potential confounding factors

Results

Results

Results

DiscussionSingle-layer hysterotomy closure at the time of

primary caesarean delivery was associated with more frequent bladder adhesions at the time of repeat caesarean when compared with double-layer closure; no differences were documented in adhesions at the other surgical sites examined.

When controlling for other surgical techniques, bladder adhesions were reported 7 times more frequently when single-layer hysterotomy closure was performed.

Double-layer hysterotomy closure generally reduces exposed raw surgical surfaces

DiscussionAdhesions are the consequence of tissue trauma

resulting from sharp, mechanical or thermal injury, infection, ischaemia or foreign bodies.

Such trauma triggers a cascade of events that begins with the disruption of stromal cells which release vasoactive substances that increase vascular permeability.

Fibrin deposits then form, containing exudates of cells, leucocytes and macrophages. Healing occurs by a combination of fibrosis and mesothelial regeneration.

DiscussionAdhesions have been associated with

increased operative difficulty and patient injury.

Among bladder injury cases, adhesions were present in 60%, compared with only 10% in controls.

Double-layer uterine closure has the potential to reduce bladder injury at the time of repeat caesarean delivery.

DiscussionSingle- versus double-layer hysterotomy closure

has been studied in the obstetrics literature primarily in relation to the uterine rupture.

Durnwald and Mercer, in 2003, performed a retrospective study of uterine rupture In their cohort, there were no differences (37% versus 32.7%, P = 0.39) in subsequent adhesions between the two groups

It is possible that their findings were caused by confounding variables, such as whether the parietal or visceral peritoneum was closed.

DiscussionThis study was retrospective and had several

limitations the datasheet did not contain a specific category for bladder adhesions.

This study analysed ‘bladder’ as a category after finding that it was mentioned frequently in the ‘other’ category this may lead to reporting bias, and we would encourage future studies of adhesion that use an adhesion score sheet to include the category ‘bladder’.

DiscussionDetails of the number of sutures placed in

hysterotomy may have been omitted in operative dictations.

The sample was small: 46 of 127 women had bladder adhesions; the confidence interval for the prevalence rate of bladder adhesions was quite large.

DiscussionThis study included many surgeons at various levels

of training. All residents were supervised by an attending

physician, but there may have been significant variability in operative technique.

Moreover, the physicians completing the adhesion score sheet were not blind to the hysterotomy closure.

Although we controlled for differences in operative technique in our multivariable logistic regression analysis, there may be residual confounding because of this heterogeneity that could not be captured.

DiscussionFinally, the best way to conduct such a study

would be a randomised controlled trial. However, when searched PubMed from 1950

to 2009 using the keywords ‘adhesions’ and ‘hysterotomy’, there is found no other studies that methodically addressed this question.

This study intention is to use the information from the current study to inform the study design of such a prospective, multicentre, randomised controlled trial of this and other caesarean surgical technique questions.

DiscussionDespite limitations, this study was strengthened by the fact

that this did not rely solely on surgical dictations to assess adhesions.

The standardised adhesion score sheet allowed to query the effect of hysterotomy closure type by both the presence and location of adhesions.

This study included only women undergoing a first repeat caesarean delivery and all surgeries were performed at a single tertiary care centre.

This study found that only bladder adhesions seemed to be affected by single- versus double-layer closure this association should be considered when closing the hysterotomy during a primary caesarean delivery, and requires further examination in large prospective trials.

CRITICAL APRAISALWhat is the research question and/hypothesis ?

Research question:What is the association between single-layer and double-layer hysterotomy closure at primary caesarean delivery and subsequent adhesion formation

What is the study type?Retrospective Cross-sectional

What is the reference population?Previous study enrolled prospectively, women undergoing first repeat caesarean delivery at Stanford University Medical Center from 1996 to 2003

CRITICAL APRAISALWhat are the sampling frame and sampling

methode?Sampling Frame

Data from previous study who had primary caesarean delivery.

Sampling MethodeConsecutive sampling technique

What are the study factor and how are they measured?

Study factor is bladder adhesion in association between single-layer and double-layer hysterotomy closure at primary caesarean deliveryMeasured by a adhesion score sheet

CRITICAL APRAISALWhat are the outcome factors and how are they

measured?The outcome is prevalence rate of pelvic and abdominal adhesions.They measured by statistical analysis

Are these sources of bias relevant to the study? Selection bias: Yes consecutive sampling

Recall bias: Yes if the first operative note was unavailableConfounding bias: Yes heterogeneity of the surgeon and the physicians completing the adhesion score sheet were not blind to the hysterotomy closure

CRITICAL APRAISALAre sample size issues considered ? Is the

power of the study indicate?No, the size sample is not consideredNo, the power of the study is not indicated

Are statistical methods described?Yes, the statistical methods are describe

CRITICAL APRAISALWhat conclusion did the author reach about the

research question ? Primary single-layer hysterotomy closure may be associated with more frequent bladder adhesions during repeat caesarean deliveries. The severity and clinical implications of these adhesions should be assessed in large prospective trials

Did they generate new hypothesis ? No, they did not

Do you agree with the conclusions ?Yes, I do

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