Effect of Single and Double Layer Cesarean Section Closure on Residual Myometrial Thickness and Isthmocele - a Systematic Review and Meta-Analysis

Objective: We set out to assess the incidence of isthmocele, its effect on residual myometrial thickness (RMT), and other complications of CD in relation to single and double-layer CD closure. We searched PubMed, SCOPUS, Web of Science, ClinicalTrials.gov, MEDLINE and Cochrane Library for relevant clinical trials assessing the use of single and double-layer uterine closure in patients undergoing cesarean sections from inception through March of 2021.
Materials and Methods: Our population was women undergoing cesarean section with uterine closure by any double-layer closure, compared with those undergoing uterine closure by any single-layer method. The outcomes we measured included residual myometrium thickness (in mm) at 6 weeks, niche/isthmocele existence at 6 weeks, residual myometrium thickness (in mm) at 6-24 months and niche/isthmocele existence at 6-24 months. In order to present the highest quality evidence, we only included clinical trials in our analysis. To perform this review, we analyzed dichotomous outcomes using percent and total, while continuous outcomes were assessed using mean difference, standard deviations, and relative 95% confidence intervals under the inverse variance method.
Results: We found that the RMT in the double-layer closure group was significantly higher at six weeks (MD= -0.43 [-0.77, -0.09]), (P=0.01) and 6 to 24 months of follow-up (MD= -1.27 [-2.28, -0.25]), (P=0.01). No difference was seen in the incidence of isthmocele in the two groups, or any of the other investigated outcomes.
Conclusion: high-quality evidence shows that double-layer closure results in a higher RMT compared with a single-layer closure, but there does not seem to be a significant difference in isthmocele formation.