Episcissors-60 in Obstetrics Anal Sphincter Injury (OASI): A Systematic Review and Meta-Analysis

Obstetric anal sphincter injury (OASI) can be minimised with appropriate use of episiotomy [1]. Episcissors-60 were designed to improve the accuracy of mediolateral episiotomy [2]. The National Institute of Health and Care Excellence (NICE) have recommended research to address the uncertain efficacy of Episcissors-60 in OASI prevention [3]. This systematic review aims to evaluate Episcissors-60 in OASI prevention.

The review was registered with Prospero-University of York. A literature search using MEDLINE, EMBASE and CINAHL databases was performed up to 31 August 2023, without limits and updated March 2025. Included studies had a comparator group: historic or parallel. Studies were screened according to PRISMA protocol [4] by two independent reviewers. Data were extracted for quantitative synthesis using RevMan5.4.1.

Eight studies were included in systematic review and meta-analysis. Two studies were randomised; the remainder were observational. Six studies were deemed high quality ≥ 7 Newcastle-Ottawa score. Six out of eight studies reported a reduction in OASI with Episcissors-60. Participants ranged from 63 to 18,880. When data were pooled; there was a significant reduction in OASI rate in total number of vaginal deliveries (RD -0.02, 95% CI[-0.04, -0.01], p = 0.009) with Episcissors-60. However, there was no significant difference in OASI rate in episiotomy deliveries (RD -0.02, 95% CI[-0.05, 0.00], p = 0.10), nor in episiotomy rate (RD 0.01, 95% CI[-0.02, 0.04], p = 0.45).

Although Episcissors-60 did not show a significant reduction in OASI rate in episiotomy deliveries, a protective effect was observed in the overall number of vaginal deliveries. This suggests a potential Hawthorne effect, warranting an adequately powered randomised controlled trial (RCT) for accurate assessment.