Omission of the bladder flap at caesarean section reduces delivery time without increased morbidity: a meta-analysis of randomised controlled trials.

Caesarean section (CS) is the most common major surgical procedure performed worldwide. Traditionally, creation of a bladder flap (BF) has been a routine surgical step at CS although recent randomised controlled trials (RCTs) have begun to question its value. We performed a meta-analysis of RCTs examining the benefits of BF formation at CS. Pubmed, Medline, Embase, CINAHL Plus(®), Web of Science Reference and Cochrane Databases online were searched in March 2012 using combinations of the terms "c(a)esarean", "bladder", "flap" and "technique". Citations identified in the primary search were screened for eligibility. Online clinical registries (www.clinicaltrials.gov, www.controlled-trials.com and www.ukcrc.org.) were also searched. The primary outcome was bladder injury. Secondary outcomes were skin incision-delivery interval, total operating time, blood loss and duration of hospitalisation. Pooled outcome measures (odds ratio [OR] and weighted mean difference [WMD]) were calculated using a random effects model. Three published RCTs and one unpublished trial identified from an online trial registry were included (n=581 women). All four trials excluded very preterm and emergency CS. Omission of the BF step at CS reduced the skin incision-delivery interval (WMD 1.27min; p=0.0001). No differences were found for bladder injury (pooled OR 0.96), total operating time (WMD 3.5min), blood loss (WMD 42ml) or duration of hospitalisation (WMD 0.07 days). Omission of the BF at elective CS does not appear to increase the rate of peri-operative complications and improves the skin incision-delivery interval. The role of BF formation in very preterm procedures and emergency intrapartum CS needs further study.