Can transperineal ultrasound improve the diagnosis of obstetric anal sphincter injuries?

INTRODUCTION AND HYPOTHESIS: Women with missed obstetric anal sphincter injuries (OASIs) are at an increased risk of anal incontinence. Our aim was to assess the accuracy of three-dimensional (3D) transperineal ultrasound (TPUS) compared with clinical examination for detecting OASIs. METHODS: A cross-sectional study of women undergoing their first vaginal delivery. Perineal trauma was initially assessed by the doctor or midwife performing the delivery (accoucheur) and women were then re-examined by the trained research fellow (KW). A 3D TPUS was performed immediately after delivery before suturing to identify OASIs. The research fellow's clinical diagnosis was used as the reference standard. A power calculation determined that 216 women would be required for the study. RESULTS: Two hundred and sixty-four women participated and 226 (86%) delivered vaginally. Twenty-one (9%) sustained OASIs. Six (29%) of these tears were missed by the accoucheur but were identified by the research fellow. TPUS identified 19 of the 21 (90.5%) OASIs. One percent (n = 2) had sonographic appearances of an anal sphincter defect that was not seen clinically. The positive and negative predictive value of TPUS to detect OASIs was 91% and 99% respectively. TPUS identified 91% of OASIs compared with 71% detected by the accoucheur, which was not statistically significant. CONCLUSIONS: The detection rate of OASIs with TPUS and with the clinical findings of the accoucheur was similar. Given the training and financial implications needed for TPUS, attention needs to be focused on the training of midwives and doctors to identify anal sphincter injuries by clinical examination.

The incidence of wound complications following primary repair of obstetric anal sphincter injury: a systematic review and meta-analysis.

OBJECTIVE: We aimed to systematically determine the incidences of wound infection and dehiscence after primary obstetric anal sphincter injury repair. DATA SOURCES: MEDLINE, Embase, CINAHL, EmCare, the Cochrane Library, and Trip Pro databases were searched from inception to February 2021. STUDY ELIGIBILITY CRITERIA: We included observational clinical studies reporting the incidences of wound infection and dehiscence after primary obstetric anal sphincter injury repair. Case series and reports were excluded. Conference articles and observational study abstracts were included if they contained enough information regarding study design and outcome data. METHODS: Data were analyzed as incidence (percentage) with 95% confidence intervals. Moreover, the prediction intervals were calculated to provide a predicted range for the potential incidence of wound complications when applied to an individual study setting. Study quality and risk of bias were assessed using the relevant tool from the Joanna Briggs Institute. RESULTS: Of 956 studies found, 39 were selected for full-text review. Moreover, 10 studies (n=4767 women) were eligible and included in the meta-analysis. All 10 studies were conducted in high-income countries (Denmark [n=1], the United Kingdom [n=3], and the United States [n=6]). The incidences of wound infection (n=4593 women) and wound dehiscence (n=3866 women) after primary obstetric anal sphincter injury repair ranged between 0.1% to 19.8% and 1.9% to 24.6%, respectively. The overall incidences were 4.4% (95% confidence interval, 0.4-8.4) for wound infection and 6.9% (95% confidence interval, 1.6-12.2) for wound dehiscence. The prediction intervals were wide and suggested that the true incidences of wound infection and dehiscence in future studies could lie between 0.0% to 11.7% and 0.0% to 16.4%, respectively. Overall, 8 studies had a high or unclear risk of bias across ≥1 assessed element. None of the studies used the same set of clinical parameters to define wound infection or dehiscence. Furthermore, microbiological confirmation with wound swabs was never used as a diagnostic measure. CONCLUSION: This was a systematic review and meta-analysis of wound infection and dehiscence incidences after primary obstetric anal sphincter injury repair. The incidence estimates from this review will be useful for clinicians when counseling women with obstetric anal sphincter injury and when consenting them for primary surgical repair.

Mediolateral/lateral episiotomy with operative vaginal delivery and the risk reduction of obstetric anal sphincter injury (OASI): A systematic review and meta-analysis.

INTRODUCTION AND HYPOTHESIS: OASI complicates approximately 6% of vaginal deliveries. This risk is increased with operative vaginal deliveries (OVDs), particularly forceps. However, there is conflicting evidence supporting the use of mediolateral/lateral episiotomy (MLE/LE) with OVD. The aim of this study was to assess whether MLE/LE affects the incidence of OASI in OVD. METHODS: Electronic searches were performed in OVID Medline, Embase and the Cochrane Library. Randomised and non-randomised observational studies investigating the risk of OASI in OVD with/without MLE/LE were eligible for inclusion. Pooled odds ratios (OR) were calculated using Revman 5.3. Risk of bias of was assessed using the Cochrane RoB2 and ROBINS-I tool. The quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: A total of 703,977 patients from 31 studies were pooled for meta-analysis. MLE/LE significantly reduced the rate of OASI in OVD (OR 0.60 [95% CI 0.42-0.84]). On sub-group analysis, MLE/LE significantly reduced the rate in nulliparous ventouse (OR 0.51 [95% CI 0.42-0.84]) and forceps deliveries (OR 0.32 [95% CI 0.29-0.61]). In multiparous women, although the incidence of OASI was lower when a ventouse or forceps delivery was performed with an MLE/LE, this was not statistically significant. Heterogeneity remained significant across all studies (I2 > 50). The quality of all evidence was downgraded to "very low" because of the critical risk of bias across many studies. CONCLUSIONS: MLE/LE may reduce the incidence of OASI in OVDs, particularly in nulliparous ventouse or forceps deliveries. This information will be useful in aiding clinical decision-making and counselling in the antenatal period and during labour.

Is there a role for transperineal ultrasound imaging of the anal sphincter immediately after primary repair of third degree tears?

OBJECTIVE: When obstetric anal sphincter injuries are identified, it is crucial that the defects are repaired appropriately to achieve a better outcome. Although the presence of an intact anal sphincter is not the sole mechanism for maintaining continence, and not all women with an anal sphincter defect are symptomatic, there is an association between sphincter defects and anal incontinence. Our aim was to evaluate whether transperineal ultrasound (TPUS) is useful in assessing anal sphincter integrity immediately following primary repair of obstetric anal sphincter injuries (OASIs). STUDY DESIGN: This is a prospective observational study of women who sustained OASIs during their first vaginal delivery. Three dimensional (3D) TPUS was performed immediately after repair of OASIs to identify anal sphincter defects. A repeat TPUS was performed 12 weeks following repair. RESULTS: 21 women sustained OASIs of whom 20 (95%) attended follow up. Eight (40%) had a grade 3a tear and 12 (60%) a 3b tear. 8/20 (40%) women had residual external anal sphincter (EAS) defects identified by TPUS immediately after repair. Of these eight defects, six (75%) persisted at 12 weeks postpartum. No new defects were seen at follow up among the twelve women in whom no defect was seen immediately following the repair. Six residual EAS defects were found at 12 weeks postpartum. An EAS defect at 12 weeks postpartum was associated with anal incontinence (p = 0.04). Women with 3b tears were more likely to have anal incontinence (AI) and residual sonographic EAS defects when compared with 3a tears but this was not statistically significant. CONCLUSIONS: Women who had no TPUS defect detected immediately following primary repair of OASIs, remained as such at 12 weeks postpartum. Of those in whom a defect was seen immediately after repair, it persisted in 75% of cases at 12 weeks. We believe that the value of TPUS immediately after repair appears to be limited and would need to be defined if it were to be considered for routine practice. Further research on its role immediately after repair of major tears (Grade 3C/4) is needed. In addition, performing ultrasound would require widespread training of obstetricians to develop expertise. This highlights the importance of adequate training of obstetricians in OASI repair.

Are Women's and Obstetricians, Views on Mode of Delivery Following a Previous Cesarean Section Really OCEANS Apart?

PURPOSE: Most women with one previous cesarean section (CS) are suitable for either a vaginal birth after CS (VBAC) or an elective repeat CS. Previously, nurse-led prenatal education and support groups have failed to have an impact on the mode of delivery, which women opted for after one CS. A novel one-stop obstetrician-led cesarean education and antenatal sessions (OCEANS) has been developed to inform and empower women in their decision-making following one previous CS. The objective of our study was to evaluate how OCEANS influences the mode of delivery for women who have previously had one CS. STUDY DESIGN: Two-hundred and sixty-six women who had a single previous lower segment CS were invited to attend OCEANS, which is a 1-h discussion group of women between 5 and 15 in number, facilitated by an experienced obstetrician. Data were collected prospectively on women who were invited to attend OCEANS over a 12-month period commencing on the 1st January 2012. RESULTS: 188 (71 %) attended the group, while 20 (8 %) canceled their appointment and 58 (22 %) did not keep their appointment. Those who attended OCEANS were 38 % more likely to opt for a VBAC than those who did not attend. There was no difference in the rates of successful vaginal delivery between women who attended OCEANS and those who did not (56 vs. 61 %, p = 0.55). CONCLUSIONS: While nurse-led prenatal education and support groups have no impact on mode of delivery after one CS, a dedicated obstetrician-led clinic increases the rate of those opting for VBAC by 38 %. Such clinics may be a useful tool helping in empowering women in their decision-making and reduce the rate of CSs.

Mediolateral episiotomy: are trained midwives and doctors approaching it from a different angle?

OBJECTIVES: The angle at which a mediolateral episiotomy is incised is critical to the risk of obstetric anal sphincter injuries (OASIS). When a mediolateral episiotomy is incised at least 60 degrees from the midline it is protective to the anal sphincter. The objective of our study was to investigate how accoucheurs described and depicted a mediolateral episiotomy. STUDY DESIGN: One hundred doctors and midwives were invited to complete an interview-administered questionnaire in a district general hospital in the United Kingdom over a 10-month period commencing in August 2012. Accoucheurs were asked to describe the angle at which they would cut a mediolateral episiotomy, and to depict this on a pictorial representation of the perineum. The angle drawn was calculated by an investigator blinded to the participant's initial description of a mediolateral episiotomy. RESULTS: Sixty-one midwives and 39 doctors participated. Doctors and midwives stated they would perform a mediolateral episiotomy at an angle of 45 degrees from the midline, but midwives depicted episiotomies 8 degrees closer to the midline (37.3 degrees vs. 44.9 degrees, p=0.013) than they described. Seventy-six percent of accoucheurs had undergone formal training in how to perform a mediolateral episiotomy, but this had no impact on their clinical practice. Accoucheurs who had been supervised for ten episiotomies before independent practice performed them in keeping with the angle they described. CONCLUSIONS: Doctors and midwives are unaware of the appropriate angle (60 degrees) at which a mediolateral episiotomy should be incised at to minimise obstetric anal sphincter injury. The correct angle should be emphasised to accoucheurs to minimise the risk of anal sphincter damage. In addition midwives depict episiotomies that are significantly more acute than they describe. Accoucheurs should also perform at least 10 episiotomies under supervision prior to independent practice. Training programmes should be devised and validated to improve visual measurement of the episiotomy incision angle at crowning. Consideration should also be given to the development of novel surgical devices that help the accoucheur to perform a mediolateral episiotomy accurately.