Single vs Double Layer Suturing in a Cesarean and it's Effect on VBACS - the negative research articles

There has been a lot of talk lately about suturing on a cesarean.  Many providers are refusing to allow vbacs with a single layer suture (as opposed to a double layer suture).  Is there really a higher risk with a single layer??  Or is it yet another way for obs to deny women the right to birth the way they choose?

I've been looking into studies which address this issue.  I'm working on getting the full studies.  In some cases, I just have abstracts to report on. There are 2 studies that show a huge increase in the rate of uterine rupture in single layer sutures.

Let's look at the first one:

STUDY 1 - I reviewed the complete study

Single- versus double-layer uterine incision closure and uterine rupture.

Authors: Gyamfi C, Juhasz G, Gyamfi P, Blumenfeld Y, Stone JL. The Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University, New York, NY, USA. drcynthiagyamfi@yahoo.com

Journal of Maternal-Fetal and Neonatal medicine, Oct 2006; 19(10): 639-643

OBJECTIVE: To evaluate whether closure of the uterine incision with one or two layers changes uterine rupture or vaginal birth after cesarean section (VBAC) success rates. (Transverse uterine incision)

METHODS: Reviewed VBAC attempts from 1/1/1996 to 12/31/2000 at the Mount Sinai School of Medicine in NYC.

Criteria for inclusion:
    Single, previous low transverse cesarean section

Criteria for exclusion:
    - multiple gestation
    - more than 1 c-section
    - previous scar other than low transverse
     - gestational age at delivery < 36 weeks
     - previous operative report unavailable

Definitions
    Uterine Rupture (UR): complete separation of the previous uterine scar with extrustion of fetal parts     into the peritoneal cavity

    Single layer closure: one continuous, locked layer of the lower segment incision

    Double layer closure: initial layer was closed in a running locked fashion; second layer was a     continuous, imbricating layer

Study size:  N = 948 women
    Single layer = 35
    Double layer = 913

Uterine Rupture (rate) =  1.6% overall
   Single layer = 3/35 (8.6%)
    Double layer = 12/948 (1.3%)
    p=0.015

Vbac success
    Single layer = 74.3%
    Double layer – 77% p= 0.685

Time interval between delivery (Months)
    Single layer = 26.4 +- 14.7 months
    Double layer = 38.6 +- 22.2 months

Induction*
    Single layer = 26.4%
    Double layer = 38.6%

* Inductions were usually done with prostaglandins.  Up until 1999, misoprostol (aka Cytotec) was regularly used for inductions in previous scarred uteri

NOTES
-    During study period, overwhelming majority of obs closed the incisions with No1. chromic.  All the UR cases involved No. 1 chromic in either a single or double layer.
- The number of women included in the single layer suture group (35) is WAY too small to be statistically significant
-    Double layer group had a longer time interval between pregnancies
-    Bujold and coworkers obtained similar results in a 2002 study published in Am J Obstet Gynecol.  However they used similar techniques:  both used chromic catgut to close the uterine incision which other studies have shown is not as good of a suturing material
-    Durnwald and Mercer found no increase in UR when 1 or 2 layers were used and their study used 0-Vicryl suture material (polyglactin 910) which is known to keep it’s tensile strength longer.
-    One quarter to one half of the women were induced.  Cytotec was used as an induction aid for 3 out of 4 years of this study.  Cytotec  should not be used as an induction aid for any women (due to increased chance of uterine hyperstimulation), especially not women with a scarred uterus!  The study does not specifically state whether cytotec (or another cervical ripening agent or pitocin) was used in the cases of UR
-    Rates in this study were much higher than commonly quoted UR rates (0.4 -0.7%).  That ALONE should raise a red flag with this study!
-    Landon, et al (2004) quoted lower UR rates in women with classical, inverted T and J incisions Landon study 2004 summary

STUDY 2 - I reviewed the full study (Additional information can found on ICAN's white papers: http://www.ican-online.org/resources/white_papers/wp_suture.pdf

The impact of a single-layer or double-layer closure on uterine rupture☆
Emmanuel Bujold, MDa, Camille Bujold, OTa, Emily F. Hamilton, MDb, François Harel, MSca, Robert J. Gauthier, MDa

American Journal of Obstetrics and Gynecology Volume 186, Issue 6, Pages 1326-1330 (June 2002)

Received 28 September 2001; accepted 20 December 2001

Objective: Our purpose was to measure the impact of a single-layer or double-layer closure on uterine rupture at subsequent delivery.

Study Design: This is an observational cohort study of all women undergoing a trial of labor from 1988 to 2000 in a tertiary care center, after a single low transverse cesarean delivery. Factors most highly associated with uterine rupture were identified by using univariate regression analysis. Multivariate logistic regression analysis was used to adjust for selected confounding variables.

Results:

N=1980
The odds ratio for uterine rupture in women with a single-layer closure was 3.95 (95% CI, 1.35-11.49).

Uterine Closure:
     Single layer = 489
            defined as: entire thickenss of the uterine wall from decidua to visceral periteneum closed with a           single continuopus interlocking suture

    Double layer = 1491
                defined as: continuous interlocking suture through the myometrium and decidua followed by a              continuous imbricating second layer and finally, closure of the viseral peritoneum.

Suturing material:  chromic catgut was used in 97.9% of all women in this study.  Polygalatin 910 (Vicryl) was used in 2.1%

Uterine rupture definition: defect that involved entire thickness of the uterine wall, including overlying periteneum with extrusion  of intrauterine contents into the perineal cavity that required operative intervention.  Cases of uterine scar dehiscence were excluded.

Uterine rupture (total rate = 1.2%)
    single layer = 15/489 (3.1%)
    Double layer = 7/1491 (0.5% )

All patients with a uterine rupture had their prior uterine incision closed by using a chromic catgut in an imbricating Lembert or Connell's suture.

Factors for risk of uterine rupture (n= 23 total ruptures in the study)
    15 ruptures were in single layer sutures
    11 ruptures occured in women <24 months from their c-sections
    20 ruptures occured in women who had epidurals
    13 ruptures occured in women who had c-sections for ftp
    8 ruptures occured in women who were induced*
    15 ruptures occured in women who were given oxytocin

* the authors states that prostaglandins were seldom used for induction at their hospital.  Intercervical extra-amniotic Foley catheters were used for cervical ripening when needed.  Between 1988 and 2000, only 6 patiends with a previous c-section received intravaginal Prostaglandin E2 for cervical ripening (it did not state whether any of these women ruptured though)

Uterine dehiscence:
     Single layer: 9/123 cesareans (7.3%)
     Double layer: 10/324 cesareans (3.1%)

VBAC success:
    76.3% of women in the study

They controlled (statistically) for the possible affects of pitocin, epidural use, age and other potentially confounding variables. The conclusion drawn was that there was a significantly higher risk of uterine rupture in women who’d had a single-layer closure of the uterus in a prior cesarean.

Conclusion: A single-layer closure of the previous lower segment incision was the most influential factor and was associated with a 4-fold increase in the risk of uterine rupture compared with a double-layer closure. (Am J Obstet Gynecol 2002;186:1326-30.)

NOTES:
    - chromic catgut suturing was used in all cases of uterine rupture
    - continuous/running locked stitches were used
    - a delivery of less than 24 months from c-section was also a large factor in uterine rupture in this         study
    - Oxytocin/pitocin was used in most of the UR cases (14/23)
    - There were 162 women excluded due to imcomplete records.  They had NO URs and 2 cases of             asymptomatic uterine scar dehiscence
     - Study only done at 1 hospital rather than collecting data from several hospitals.

There were several Letters to the Editor of the American Journal of Obstetrics and Gynecology regarding this study.  Here are some of the comments:

reference: Am J Obstet Gynecol (2003) Vol 188 (1)

"I believe that the reason for their better outcome in the two-layer closure group has little to do with the number of layers in the closure, but rather that the second layer was closed with a nonlocking stitch. Almost as an afterthought in their discussion, the authors indicate that the second imbricating layer may cause “less vascular occlusion.” The running locking stitch, like figure-of-eight stitches, causes vascular occlusion within the area surrounded by suture. These stitches were designed for hemostasis. I believe that it is entirely possible that they lead to weaker uterine scars because of vascular occlusion leading to poor healing.

...that the strongest and most satisfactory uterine closure at the time of cesarean delivery resulted from simple interrupted surgical gut sutures. One of the reasons put forth by the author for his findings was less vascular occlusion caused by the simple interrupted sutures as opposed to the running locking sutures.
I believe that the uterus can be closed in a single layer, but this should be either simple interrupted sutures or a running nonlocking stitch.
Dwight P. Cruikshank MD"

Authors reply to that Letter to the Editor

"The suture material in use was almost always chomic catgu.  We had no examples of single-layer closure with interrupted sutures, nor were we able to find a study that examined rates of uterine dehiscence or uterine rupture with this type of closure.

To date, we have found no studies comparing the effect of continuous nonlocking vs continuous locking sutures on the lower uterine segment.

According to our results and htese hysterographic studies, we are led to believe that a continuous locking suture for the closure of the ueterus in a single layer is not the ideal closure for patients planning a future pregnancy and should be reserved for womne who are having a tubal ligation done with the cesarean section.

Emmanuel Bujold, MD, Emily F Hamilton, MD and Robert J. Gauthier, MD"

Comments

[Surgical Sutures]

Always better to have a double layer suture to be on the safer side...