2022 exceptional surveillance of Intrapartum care for healthy women and babies investigating angle of episiotomy and rectal examination practice (2017)

Methods

The exceptional surveillance process consisted of:

For further details about the process and the possible update decisions that are available, see ensuring that published guidelines are current and accurate in developing NICE guidelines: the manual.

Search and selection strategy

We searched for new evidence related to the angle of episiotomy and best practice for rectal examination.

We found 16 studies in a search for randomised controlled trials, systematic reviews and observational studies published between 11 February 2014 and 24 June 2022.

See evidence identified from searches for details of all evidence considered. Full references are provided at the end of the document.

Multiple obstetric guidelines update committee feedback

The committee advised that differences between CG190recommendations and the OASICB are causing confusion in practice. The committee noted that in many trusts the OASICB is perceived as being more up to date than CG190 but that some professionals have concerns about the evidence for some of the OASICB's elements. The committee therefore advised that the latest evidence about the areas not covered by the scheduled update of CG190, namely the optimal angle of episiotomy and rectal examination practices needs to be assessed in a surveillance review.

The OASI Care bundle

The OASICB consists of four elements: 1. antenatal information for women informing them about OASI and what can be done to minimise the risk, 2. Use of MPP in labour (where the clinician uses their hands to support the perineum and baby's head) for all singleton vaginal births, conditional on consent, 3. mediolateral episiotomy at a 60 degree angle, conditional on clinical indication, 4. routine rectal examination.

OASICB is based on a multicentre observational study using a stepped-wedge cluster design (Gurol-Urganci et al 2020)) comparing 28,000 singleton vaginal births that took place before implementation of the care bundle with 27,000 that took place after implementation. The authors found that OASI was reduced overall by 0.3% (odds ratio (OR) 0.80, 95% CI 0.65–0.98, p=0.03). A subgroup analysis reports that while this remained significant for spontaneous births it was not significant for forcep-assisted or vacuum assisted births. There was no impact of the OASICB on episiotomy rate

A qualitative exploratory study (Bidwell et al 2020) explored healthcare professional's (n=101) perspectives of the bundle using focus groups in 16 centres. It reports mixed reactions from practitioners about the care bundle and that engagement through awareness-raising and training is the key to clinical buy-in and successful implementation.

Evidence identified from searches

Additional evidence about angle of episiotomy and rectal examination practices was identified by searches and is summarised below from the information presented in their abstracts.

Angle of episiotomy

One RCT (El-din et al. 2014) (n=330 primiparous women) conducted in an Egyptian maternity hospital compared 60 degree mediolateral episiotomy with 40 degree from midline. It reported 60 degree angle was associated with significantly higher rates of severe-moderate episiotomy-related pain post-partum. At 6-months there was no statistically significant differences between groups for episiotomy-related pain or dyspareunia.

An observational study (Ginath et al. 2017) of 102 women (50 primiparous, 52 multiparous) investigated the impact of timing of episiotomy on angle. Study authors marked 30, 45, and 60 degree angles respectively from midline during the first stage of labour and measured them again during crowning and reported all angles increased by more than 30 degrees. The authors conclude this change needs to be accounted for when marking episiotomy angles for cutting.

Episiotomy tools with cutting angle guides

Episcissors-60

Six studies were identified (Cole et al. 2019; Divakova et al 2020.; Kastora et al. 2021; Koh et al 2020; Van Roon et al 2015; and Mohuidin et al. 2015) about the effectiveness of Epicscissors-60, a product designed to enable a cutting angle of 60 degrees at crowning. This technology was assessed in February 2020 by Episcissors-60 for mediolateral episiotomy (NICE Medical technologies guidance 47 (MTG47)) which included 4 studies identified by this surveillance. Two studies post-dating MTG47 were also identified: Kastora et al. 2021 and Koh et al 2020. The MTG47 manufacturer submission included 'academic in confidence' data from the latter study but it had not fully published at the time of MTG47 development. These studies are summarised below, and we will share them with NICE's medicines technology guidance team for assessment in relation to MTG47.

Episcissors−60 is considered relevant to this surveillance review as MTG47 reports use of the technology results in post-suture angles between 40 and 53 degrees when it is used during crowning, an angle there is evidence to suggest is associated with a lower risk of OASI (e.g.,Kalis et al. (2011); Sawant, G. and Kumar, D. (2015)). The MTG47 expert advisory committee (EAC) noted that the impact of reusable Episcissors−60 on the incidence of QASIS was uncertain, and that further evidence for the single use version of the technology was needed. Additionally, they noted further evidence is needed to attribute benefit to Episcissors−60 for reducing OASI over and above standard bundles of care.

Overall MTG47 concludes that the technology is 'promising' but does not recommend routine adoption by the NHS until further research is available about its impact on OASI. This is largely based on an MTG47 EAC meta-analysis of 5 studies comparing episiotomy performed with Episcissors-60 versus standard scissors that suggests no statistically significant risk difference in favour of Episcissors−60. However, another EAC meta-analysis of two UK studies (Mohuidin et al. (2015)) and (Van Roon et al. (2015)), found that Episcissors−60 when used as part of a bundle of care, reduces OASI rates in women who have had an episiotomy (risk difference= − 0.04, [95% CI − 0.08 to − 0.00, p=0.03], (n=76 episiotomies). It is notable that Mohuidin et al. investigates the use of Episcissors-60 as part of a bundle of care based on RCOG guidelines. MTG47 notes that overall, the evidence base is limited to a small number of before and after studies with a high risk of bias.

The two studies identified by this surveillance review post-dating MTG47 are as follows:

Other cutting tools

A cohort study (Gonzalez-Diaz et al. 2020) investigated the impact of an intervention that could include use of the Triepi-45 tool (designed to enable a 45-degree episiotomy angle) on the rates of OASI during OVD (n=1972). It reports no statistical difference in rates of OASI in the preintervention versus postintervention cohorts (7.1% vs 9.4%) and a low usage rate of the tool (343/986). A subgroup analysis of the cohort where Triepi-45 was used showed a significantly reduced OASI rate (18/375 vs 93/986) (odds ratio, 0.47; 95% CI 0.26-0.86), but it is notable this is based on small event rates. No detail is provided as to why the tool was or was not used. Neither cutting nor suture angle are reported and the study is therefore of limited value to this surveillance review.

Topic expert feedback

We asked 3 members of the multiple obstetric guidelines update committee the following questions about episiotomy:

We received 2 responses. One topic expert responded to say that a 60 degree cutting angle at crowning translates into a 42 degree suture angle postnatally, a number within the range reported by MTG47. They noted that evidence suggests when an episiotomy is cut at more than 60 degrees or less than 40 degrees the incidence of OASI increases. They also noted evidence suggests it is very difficult for a clinician to estimate this cutting angle and that there are tools, e.g., Episcissors, that can help to facilitate it and that the OASI care bundle recommendation is partly informed by this. A second topic expert responded to say they agreed that using a 60 degree cutting angle at crowning resulted in a postnatal angle of 42 degrees, an angle associated with lower rates of OASI. However, they also noted that occasionally (less than 1 in 100 normal births), episiotomy can be undertaken in advance of crowning to hasten birth when there is concern about fetal condition and to avoid an instrumental birth. The expert suggested that in those circumstances the cutting angle would be less than 60 degrees.

Impact statement

There is very little evidence that directly compares cutting angles on OASI outcomes. Only 1 RCT directly compared angles and reports more pain immediately post-partum for a 60 degree angle compared with 40 degree in an Egyptian population. Studies assessing the Episcissors−60 tool, designed to guide practitioners to make a 60 degree cut at crowning report resulting suture angles ranging from 40 to 53-degrees, and also there is limited evidence from Episcissors-60 for mediolateral episiotomy (NICE Medical technologies guidance 47) that use of this tool as part of a care bundle is associated with small reductions in the incidence of OASI. New evidence not included by MTG47 further suggests an association between Episcissors−60 and reduced OASI rates, particularly during OVD.

RCOG's recommendation of a 60 degree angle of episiotomy is based largely on an observational study (Kalis et al. 2011) that reports suture angle following episiotomy is more important than incision angle in reducing OASI; and a suture angle of 40 to 60 degrees can best be achieved at crowing with a 60 degree cutting angle.

There is limited evidence that the measured angle of cut changes significantly depending on the timing of episiotomy due to distension of the anatomy. A topic expert consulted during this surveillance also noted that although episiotomies conducted prior to crowning are not common, when they are conducted a cutting angle of less than 60 degrees is required. This evidence supports recommending a range of angles at the time of episiotomy as per CG190-1.13.20 in order to achieve suture angles associated with lower risk of OASI. CG190-1.13.20 therefore accommodates situations where episiotomy may have to be undertaken prior to crowning. We propose retaining recommendation 1.13.20 as it accommodates use of a 60-degree cutting angle at crowning while also allowing for situations where episiotomies need to be performed prior to crowning.

Rectal examination

One RCT (Ozyurt et al. 2015) was identified that compared the number of sphincter injuries in primigravid women (n=201, SVD with mediolateral episiotomy after 36-weeks' gestation) identified by physical examination with those identified by transvaginal sonography (TVS). It reports physical examination classified 194/201 cases as not involving the sphincter (second degree tears) while TVS classified 171/201 tears as causing 'no defect to the sphincter.' There were 23 cases (11.5%) of 'occult tears' i.e., tears undetected by physical examination but detected by TVS. The injuries resulting from these occult tears were classified by TVS operators as external sphincter partial defects at the lower end of injury severity.

Impact statement

No studies were identified comparing routine with restricted rectal examination and there is no evidence to suggest that restricted rectal examination as recommended by CG190-1.16.5 increases the risk of poor outcomes. One study comparing routine examination with TVS suggests that there may be a role for TVS in supporting OASI identification, but new evidence alone is not enough on which to base a recommendation. We will add this issue to CG190's issues log.

Angle of episiotomy

Recommendation CG190-1.13.20 is based on a prospective observational study from 2006 (full guideline p.598) of women (n=241) giving birth vaginally for the first time that investigates risk factors for third- and fourth-degree perineal tears. It reports higher birthweight (p=0.021) and mediolateral episiotomy (OR 4.04 [95% CI 1.71 to 9.56]) as independent risk factors for sphincter injury. Further investigation in the study revealed that episiotomies angled closer to the midline were significantly associated with anal sphincter injuries (26 versus 37 degrees, p=0.01). No midwife and only 22% of obstetricians performed 'true' mediolateral episiotomies which the authors state is defined as being at least 40 degrees from the midline as given in 'standard obstetric and midwifery texts.'

Rectal examination

Recommendation CG190-1.16.5 is based on 3 studies (full guideline p.745-746). The first is a before- and after-study evaluating a perineal assessment and repair course; the other 2 are prospective intervention studies examining the incidence of third- and fourth-degree perineal trauma that highlight under-diagnosis as a problem in this aspect of care. This evidence was assessed by reviewers as low-level evidence supporting recommendations for the systematic assessment of the vagina, perineum, and rectum in order to adequately assess the extent of perineal trauma.

Both recommendations date from 2007 and the committee discussion is not reported in the current version of the guidelines.

Angle of episiotomy

A meta-analysis of 15 observational studies (n=not reported) (Lund et al 2016) was identified investigating lateral and medio-lateral episiotomy during vacuum assisted birth that reported both significantly reduced OASI. The NICE surveillance review concluded that the new evidence is specific to women undergoing vacuum assisted delivery and because there are no differences in outcomes between groups receiving the interventions, impact on the guideline recommendations was unlikely.

Rectal examination

No evidence related to best practice in rectal examination was identified.