Maternal morbidity following cephalad-caudad versus transverse blunt expansion of the low transverse uterine incision during cesarean section: a meta-analysis of RCTs
Creators: name: Pergialiotis, Vasilios
name: Daskalakis, Georgios
name: Alexandros, Rodolakis
name: Bellos, Ioannis
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Obstetrics and Gynecology
subject: Medicine and Health Sciences
subject: Medical Specialties

description: Cesarean section is the most prevalent surgical procedure worldwide that reached approximately 29.7 million cases in 2015. It is directly associated with increased risk of maternal and neonatal morbidity in the absence of malpresentation. Several techniques have been investigated and reports suggest that cephalad-caudad expansion of the uterine incision is associated with improved maternal outcomes compared to traditional transverse blunt expansion. The purpose of this meta-analysis is to accumulate data from published randomized trials (RCTs). The present meta-analysis will be designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [12]. The study will be based in aggregated data that have been already published in the international literature. Patient consent and institutional review board approval will not be retrieved as they are not required in this type of studies. Types of studies and patients The eligibility criteria for the inclusion of studies will be predetermined. Randomized controlled trials that assess the impact of cephalad-caudad blunt expansion of the low transverse uterine incision during CS to those of transverse blunt expansion will be selected for inclusion. Studies will be selected irrespective of the gestational age at delivery and of the parity status of parturient. Observational studies, case series, case reports, experimental studies and conference proceedings will be excluded from the present systematic review. Information sources and search methods We will use the Medline (1966–2020), Scopus (2004–2020), Clinicaltrials.gov (2008–2020), EMBASE (1980-2020), Cochrane Central Register of Controlled Trials CENTRAL (1999-2020) and Google Scholar (2004-2020) databases in our primary search along with the reference lists of electronically retrieved full-text papers. The date of our last search will be set at January 10th, 2021. Our search strategy will include the text words “transverse, cephalad, caudad, blunt, cesarean section” and is presented in brief in Supplemental Figure 1. Studies will be selected in three consecutive stages. Following deduplication, the titles and abstracts of all electronic articles will be screened by three authors (D.M., E.B. and I.B.) to assess their eligibility. The decision for inclusion of studies in the present meta-analysis will be taken after retrieving and reviewing the full version of articles that will be considered potentially eligible. Discrepancies that arise in this latter stage wll be resolved by consensus from all authors. Predefined outcomes Data extraction will be performed using a modified data form that was based in Cochranes data collection form for intervention reviews for RCTs and non-RCTs [13]. Predetermined primary outcomes will include the risk of incision extension, need for additional sutures and need for transfusion. Secondary outcomes will include differences in intraoperative blood loss, risk of uterine vessel injury and of ureteral injury, risk of uterine atony, need for additional uterotonics and need of incision extension (in the form of J-incision of inverted T-incision). Assessment of risk of bias The methodological quality of the included studies will be assessed by two independent reviewers (A.P and V.K.) using the Risk of Bias 2 (RoB2) tool [14]. RoB2 incorporates 5 domains that include assessment of i) risk of bias that arises from the randomization process, ii) risk of bias due to deviations from the intended interventions, iii) missing outcome data, iv) risk of bias in measurement of the outcome and v) risk of bias in selection of the reported result. Statistical analysis Statistical meta-analysis will be performed with RStudio using the meta function (RStudio Team (2015). RStudio: Integrated Development for R. RStudio, Inc., Boston, MA URL http://www.rstudio.com/). Statistical heterogeneity will be considered during the evaluation of the appropriate model (fixed effects or random effects) of statistical analysis as the following assessment of the methodological heterogeneity of included studies. Confidence intervals will be set at 95%. We calculated pooled risk ratios (RR), mean differences (MD) and 95% confidence intervals (CI) with the Hartung-Knapp-Sidik-Jonkman instead of the traditional Dersimonian-Laird random effects model analysis (REM). Publication bias will be assessed pending adequacy of number of studies is achieved [17]. Prediction intervals Prediction intervals (PI) will be also calculated, using the meta function in RStudio, to evaluate the estimated effect that is expected to be seen by future studies in the field. The estimation of prediction intervals takes into account the inter-study variation of the results and express the existing heterogeneity at the same scale as the examined outcome. Trial sequential analysis To evaluate the information size, we will perform trial sequential analysis (TSA) which permits investigation of the type I error in the aggregated result of meta-analyses performed for primary outcomes that were predefined in the present meta-analysis. A minimum of 3 studies will be considered as appropriate to perform the analysis. Repeated significance testing increases the risk of type I error in meta-analyses and TSA has the ability to re-adjust the desired significance level by using the O Brien-Flemming a-spending function. Therefore, during TSA sequential interim analyses are performed that permit investigation of the impact of each study in the overall findings of the meta-analysis. The risk for type I errors was set at 5% and for type II errors at 20%. The TSA analysis was performed using the TSA v. 0.9.5.10 Beta software (http://www.ctu.dk/tsa/).