Obstetric anal sphincter injuries (OASIS) are associated with numerous consequences as anal fecal incontinence, fecal urgency, dyspareunia and psychological effects for women. A meta-analysis found that 30% - 50% of women were symptomatic one year after OASIS, even with repaired[1, 2]. And it could result in as high as 53% - 80% of longer-term anal incontinence and urgency[3, 4], affecting women’s quality of life. The purpose of episiotomy is to expedite delivery for fetal distress, increase the vaginal outlet of instrumental deliveries or shoulder dystocia, or to reduce the risk of OASIS[5]. Episiotomy as the most important preventative measure to reduce third-and fourth-degree or OASIS is used worldwide, despite the confliction of the protective effect[6, 7]. Episiotomy technique usually contains three main parameters: the length of the incision, the incision angle, and the distance between the start point and the posterior fourchette. Several episiotomies were described, the midline episiotomy is associated with high rates of OASIS[8-10], compared with mediolateral episiotomy (MLE), there was no significant difference in pain, dyspareunia and infection rates[11].
The WHO recommends restrictive use of episiotomy, and states that episiotomy should be considered as following: complicated vaginal delivery (breech, shoulder dystocia, forceps or vacuum extraction), scarring from female genital mutilation or poor healed third-or fourth-tears, fetal distress. Restrictive episiotomy resulted in less OASIS and fewer healing complications compared to routine episiotomy[12]. In China, the use of episiotomy is restrictive and left MLE is considered standard practice.
The internationally accepted standardized definition or categorization of episiotomy is still on the way, the National institute of Health and Care Excellence (NICE 2007) guideline for intrapartum care recommended that a MLE should perform originating at the vaginal fourchette and the angle to the vertical axis should be between 45 and 60 degrees. Dharmesh et al. found that perineal distension of 170% in the transverse direction and 40% in the vertical direction at crowning, there were 15-30 degree between episiotomy incision angles and suture angles, the suture angles of 40-60 degrees were in the safe zone[9].Performing a MLE at least 60 degree from midline could in fact protect against OASIS[13], and there was a U-shaped association between suture angles and risk of OASIS, Stedenfeldt et al. regarded suture angle of 30-60 degrees as the safe zone[14]. When suture angle was 25 degrees, there was a 10% incidence of OASIS and each additional 6 degrees away from midline could reduce half of this risk, the incidence was only 0.5% at the suture angle of 45 degrees[15-17]. The revised Royal College of Obstetricians and Gynecologists (RCOG) (Green-top guideline 2015 NO.29) recommends three preventative measures to reduce the risk of OASIS as flowing: episiotomies at 60 degrees to the midline at crowning, manual perineal protection and warm perineal compresses in second stage of labor.MLE must be performed correctly for better preventing anal sphincter injury. Trainings became the main method of improving skills for junior obstetricians and midwives. The knowledge of performing a proper MLE and repair had universally introduced and trained. Obstetricians tended to cutting longer episiotomy and more obtuse angle compared with midwives[18, 19]. Personal career may affect the effect of such training. Simulated training as an extensive used method for obstetric education is usually practiced for beginners. The different impact of training on senior and junior practitioners is rare seen in previous researches. Herein, we offered a course with simulated practice of performing a mediolateral episiotomy (MLE) for obstetrician and midwives in different seniority, and to evaluate the training effect. Methods:
Eighty-two participants were recruited at three different obstetric centers, included 35 obstetricians and 47 midwives. More than 5 years obstetric work in their careers were deemed to senior ones, and there were 29 junior and 53 senior ones. We used a mode of “operate-train-operate” to immediately evaluate the effect of training course. A 30 minutes training course were given to all participants by one senior obstetrician. This course mainly described in three scenarios about episiotomy: (i) detail of perineal anatomy and the transformation at crowning, (ii) how to perform a MLE incision properly, (iii) techniques for repairing an episiotomy and perineal tears.
Before the training course, participants were asked to complete a cross-sectional questionnaire, which contained occupations of obstetrician or midwife, obstetric work years, 3 single choice questions ( knowledge about perineum anatomy, cases of delivery and episiotomy) and 4 multiple choices questions (history of training about episiotomy, causes for mediolateral episiotomy, worry about most when cutting a mediolateral episiotomy and main concerned about when severe tear happened) (figure1). A commonly used episiotomy incision pad with anus denoted by a cross and posterior vagina by a semi-circle (figure 2) was used for everyone to cut MLE as their usual practice. After taking back the pad and questionnaire, the training course were given. A MLE as a surgical incision is recommend given between 45-60 degrees from the midline[20]. Recommended values about the incision length and distance had not been reported in literatures yet, we usually cut MLE length in 3-4 cm and distance around 1cm, the length approximately met the scared length 17 mm according to the perineal distension at crowning[5, 14]. The French College of Gynecologists and Obstetricians (2005) recommends a mediolateral incision over an average length of 6 cm. In this course, we had taught the participants that the following parameters may be the most suitable ones: length of 3-4 cm or more, angle of 45-60 degrees and distance of 0.9 cm or more. We considered those incisions to be correct according to these criteria. Then the participants were invited to cut the pad according to those they had learned from the course. They were prompted to make MLE at 60 degrees, more than 3 cm in length and proper distances from fourchette. A unique number was created by each participant and marked in their own pads and questionnaire. Three parameters were considered for every episiotomy incision: (i) the distance of starting point of the incision from fourchette in millimeters (D), (ii) the angle of incision to the perpendicular in degrees (A), (iii) the length of the incision in millimeters (L). (figure 2)
Angles and distances were measured using common protractors and rulers. Continuous variables are presented as mean ± sd or median and range, as appropriate. Categorical variables are presented as rate. The t test was used to compare continuous variables and the chi-squared test was used to analyze categorical variables. All tests applied were two-tailed, statistical significance was considered at p < 0.05. Data were analyzed by SPSS statistical software (SPSS 19, Inc., Chicago, IL). This study was approved by the Ethics Committees of Women’ hospital, School of Medicine Zhejiang University and Approval number 20190057, and all the participates were verbally informed the project and consented to participate.