Comparative study of episiotomy angles achieved by cutting with straight Mayo scissors and the EPISCISSORS-60 in a birth simulation model

Abstract

Introduction and hypothesis: We compared the clinician's ability to cut episiotomies at the recommended 60° angle with traditional straight Mayo scissors compared with patented fixed-angle episiotomy scissors EPISCISSORS-60® in a simulated setting using mounted incision pads. The hypothesis was that fixed-angle episiotomies would achieve a more accurate cutting angle of 60°.

Methods: Angles were cut on episiotomy incision pads in a mounted birth model simulating crowning: 110 midwives and doctors cut an 60° episiotomy with Mayo scissors and then EPISCISSORS-60. Angles were measured with protractors. Average angles were calculated and the one-tailed paired t test was used to compare groups.

Results: Mean angle was 45° with Mayo scissors [SD = 9, 95% confidence interval (CI) = 43.3-46.7, interquartile range (IQR) 38-50] and 60° with the EPISCISSORS-60 (SD = 3, 95% CI = 59.3-60.7, IQR = 58-60). Two-thirds of cuts with Mayo scissors were below 50°.

Conclusions: In a simulated setting the majority of operators are unable to cut an episiotomy at the recommended 60° angle with Mayo scissors. The EPISCISSORS-60 cut an episiotomy a statistically significant 15° wider than regular Mayo scissors and achieved the recommended 60° in the vast majority of cases. If these findings translate into real life situations, then cutting episiotomies at 60° is expected to make a valuable contribution in reducing third- and fourth-degree tears in both spontaneous and operative vaginal deliveries. Variability in mediolateral episiotomies should be reduced by use of fixed-angle scissors or through validated health professional training programmes to improve visual accuracy.

Keywords: EPISCISSORS-60; Episiotomy; Mediolateral episiotomy; Obstetrics anal sphincter injuries (OASIS); Perineal trauma; Simulation model.