The prevention of perineal trauma during vaginal birth.

Perineal trauma after vaginal birth is common, with approximately 9 of 10 women being affected. Second-degree perineal tears are twice as likely to occur in primiparous births, with a incidence of 40%. The incidence of obstetrical anal sphincter injury is approximately 3%, with a significantly higher rate in primiparous than in multiparous women (6% vs 2%). Obstetrical anal sphincter injury is a significant risk factor for the development of anal incontinence, with approximately 10% of women developing symptoms within a year following vaginal birth. Obstetrical anal sphincter injuries have significant medicolegal implications and contribute greatly to healthcare costs. For example, in 2013 and 2014, the economic burden of obstetrical anal sphincter injuries in the United Kingdom ranged between £3.7 million (with assisted vaginal birth) and £9.8 million (with spontaneous vaginal birth). In the United States, complications associated with trauma to the perineum incurred costs of approximately $83 million between 2007 and 2011. It is therefore crucial to focus on improvements in clinical care to reduce this risk and minimize the development of perineal trauma, particularly obstetrical anal sphincter injuries. Identification of risk factors allows modification of obstetrical practice with the aim of reducing the rate of perineal trauma and its attendant associated morbidity. Risk factors associated with second-degree perineal trauma include increased fetal birthweight, operative vaginal birth, prolonged second stage of labor, maternal birth position, and advanced maternal age. With obstetrical anal sphincter injury, risk factors include induction of labor, augmentation of labor, epidural, increased fetal birthweight, fetal malposition (occiput posterior), midline episiotomy, operative vaginal birth, Asian ethnicity, and primiparity. Obstetrical practice can be modified both antenatally and intrapartum. The evidence suggests that in the antenatal period, perineal massage can be commenced in the third trimester of pregnancy to increase muscle elasticity and allow stretching of the perineum during birth, thereby reducing the risk of tearing or need for episiotomy. With regard to the intrapartum period, there is a growing body of evidence from the United Kingdom, Norway, and Denmark suggesting that the implementation of quality improvement initiatives including the training of clinicians in manual perineal protection and mediolateral episiotomy can reduce the incidence of obstetrical anal sphincter injury. With episiotomy, the International Federation of Gynecology and Obstetrics recommends restrictive rather than routine use of episiotomy. This is particularly the case with unassisted vaginal births. However, there is a role for episiotomy, specifically mediolateral or lateral, with assisted vaginal births. This is specifically the case with nulliparous vacuum and forceps births, given that the use of mediolateral or lateral episiotomy has been shown to significantly reduce the incidence of obstetrical anal sphincter injury in these groups by 43% and 68%, respectively. However, the complications associated with episiotomy including perineal pain, dyspareunia, and sexual dysfunction should be acknowledged. Despite considerable research, interventions for reducing the risk of perineal trauma remain a subject of controversy. In this review article, we present the available data on the prevention of perineal trauma by describing the risk factors associated with perineal trauma and interventions that can be implemented to prevent perineal trauma, in particular obstetrical anal sphincter injury.

Postpartum perineal wound infection and its effect on anal sphincter integrity: Results of a prospective observational study.

INTRODUCTION: Perineal wound infection can affect tissues at superficial, deep, and organ space levels. Women with obstetric anal sphincter injuries (OASIS) are at risk of infection; however, no study to date has investigated if infection can extend to affect the anal sphincter integrity. The aim of this study was to evaluate the clinical progression of perineal wound infection and its effect on the anal sphincter in women with or without OASIS using three-dimensional endoanal ultrasound (3D-EAUS). MATERIAL AND METHODS: Women were recruited into the Prospective Observational Study Evaluating the Sonographic Appearance of the Anal Sphincter in Women With Perineal Wound Infection Following Vaginal Delivery (PERINEAL Study) between August 2020 and August 2021 (NCT04480684). 3D-EAUS was performed weekly until complete wound healing. Significant bacterial colonization was diagnosed using the MolecuLight i:X camera. The primary study outcome was a change in a sphincter defect angle from baseline (wound infection) until wound healing. A robust Poisson regression model was used to analyze the effect of significant bacterial loads on the anal sphincter. RESULTS: Seventy-three women were included. A median of two ultrasound scans were performed in each patient (range 1-16). Five women (6.8%) had an OASI clinically diagnosed at delivery. In total, 250 EAUS were performed. An external anal sphincter defect was found on EAUS in 55 (22.0%) scans (n = 10 women). An external anal sphincter and internal anal sphincter defect was found in 26 scans (10.4%) (n = 3 women). During the course of the wound healing process, there was no significant change in defect size in wounds with or without significant bacterial colonization. In cases of an intact anal sphincter, wound infection did not disrupt its integrity. CONCLUSIONS: We found that perineal wound infection does not disrupt an intact anal sphincter or OASIS. This new information can provide important information for clinicians and patients. As there are myths frequently encountered in cases of litigation when disruption of sphincter integrity is attributed to perineal infection, the findings of this study should be tested in larger studies in the future.

The incidence of anal incontinence following obstetric anal sphincter injury graded using the Sultan classification: a network meta-analysis.

OBJECTIVE: This study aimed to systematically determine and compare the incidence of anal incontinence between those with different grades of obstetric anal sphincter injury. DATA SOURCES: Ovid MEDLINE, Embase, and the Cochrane Library were searched from January 2000 to April 2021. STUDY ELIGIBILITY CRITERIA: Observational studies investigating the incidence of anal incontinence following an obstetric anal sphincter injury that was graded using the Sultan classification were eligible for inclusion. To allow comparison between individual tear grades (3a, 3b, 3c, fourth), a network meta-analysis was performed using Stata (version 15.1). METHODS: For binary outcomes, odds ratios with corresponding 95% confidence intervals were reported. Obstetric anal sphincter injury grades were ranked from the best clinical outcome to the worst clinical outcome. The percentage chance of each grade taking each rank with regards to outcome was calculated. Study quality and risk of bias was assessed using the relevant tool from the Joanna Briggs Institute. RESULTS: Of the 696 studies identified, 10 were eligible for inclusion and were included in the network meta-analysis (n=2467 women). The mean incidence of anal incontinence among those with 3a tears was 22.4% (range, 6.1%-51.2%), 24.9% (range, 6.9%-46.7%) among those with 3b tears, 26.8% (range, 0%-55.6%) among those with 3c tears, and 28.6% (0%-71.4%) among those with fourth-degree tears. Anal incontinence incidence was found to be significantly higher among those with 3c (odds ratio, 1.79; 95% confidence interval, 1.09-2.94) and fourth-degree tears (odds ratio, 2.37; 95% confidence interval, 1.40-4.02) than among those with 3a tears. In addition, anal incontinence incidence was significantly higher among those with fourth-degree tears (odds ratio, 1.89; 95% confidence interval, 1.10-3.22) than among those with 3b tears. Those with 3a tears had the highest probability of having the best clinical outcome; those with 3b; second-, 3c; third- and fourth-degree tears had the highest probability of having the worst clinical outcome. Overall, all studies had a high or unclear risk of bias across 1 or more assessed element. CONCLUSION: This was a network meta-analysis comparing the incidence of anal incontinence among those with different grades of obstetric anal sphincter injury. Increasing tear-grade severity is associated with worse clinical outcomes. This study provides useful, clinically applicable information that can assist clinicians in the counseling of women following an obstetric anal sphincter injury. In addition, it highlights the importance of accurately diagnosing the obstetric anal sphincter injury grade and subsequently performing the appropriate repair.

Bacterial autofluorescence in infected perineal wounds: A prospective cohort study.

Diagnosis of perineal wound infection based solely on clinical signs and symptoms is subjective, and often incorrectly identifies wounds with clinically significant bacterial loads. New advances in wound care such as bacterial fluorescence imaging allow point-of -care assessment of bacterial burden. This single-center, prospective observational study included 80 women with perineal wound infection and aimed to determine the incidence of significant bacterial colonization identified with bacterial fluorescence imaging. Also, to evaluate the diagnostic accuracy of bacterial fluorescence imaging. 30 women (37.5%) had fluorescence in their wounds despite antibiotic therapy. The sensitivity of bacterial fluorescence imaging in the diagnosis of wounds with a clinically significant bacterial burden was 83% and specificity was 90%. The positive predictive value was 92% and negative predictive value was 80%. Overall, diagnostic accuracy was substantial. The results of this study demonstrate that bacterial fluorescence imaging can provide real-time information surrounding the bacterial burden of perineal wounds. ClinicalTrials.gov NCT04480684.

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.

Healing of disrupted perineal wounds after vaginal delivery: a poorly understood condition.

Perineal injury following childbirth can result in complications such as wound infection and dehiscence. The reported incidence of these complications in the literature range between 0.1-23.6% and 0.2-24.6%, respectively. However, the healing of disrupted perineal wounds is poorly understood. In addition, it is a neglected area in maternity services. In this review, the authors explore the process of wound healing in the context of infected perineal wounds following childbirth. In addition, the authors describe the management of complications including hypergranulation, perineal pain and dyspareunia.

Early secondary repair of obstetric anal sphincter injuries (OASIs): experience and a review of the literature.

INTRODUCTION AND HYPOTHESIS: Secondary anal sphincter repair for a dehisced obstetric anal sphincter injury (OASI) is required following 2.6% of primary repairs. There is growing evidence that instead of delaying repair for 3-6 months, early secondary repair of the anal sphincter can be completed within 14 days. Our aims were to review the literature and to describe experiences in our unit. METHODS: This is a narrative review of all published cases reporting outcomes of early secondary repair of dehisced OASIs. In addition, we report a series from Croydon University Hospital (CUH) between 2010 and 2019. RESULTS: Ninety patients from five studies were identified on literature search. Six patients from CUH were included in the case series. Overall, the most common complications following secondary repair included skin dehiscence [10.3% (n = 10)], infection [5.2% (n = 5)] and fistula formation [8.2% (n = 8)]. In our case series, following secondary repair, normal manometric incremental squeeze pressure was found in five women (83%). Also, on endoanal ultrasound, internal anal sphincter (IAS) defects were found in 75% with a history of IAS injury (n = 4). There were no full-thickness external anal sphincter defects. Compared to those requiring primary repair alone, residual defects were significantly larger in those who also underwent secondary repair (Starck score 2.1 vs. 5.7, p = 0.01). CONCLUSION: Early secondary repair is a feasible surgical procedure for the reconstruction of dehisced OASIs. This case series and review of the literature can be used to support clinicians in the management of primary OASI repair dehiscence.

Effect of a subsequent pregnancy on anal sphincter integrity and function after obstetric anal sphincter injury (OASI).

INTRODUCTION AND HYPOTHESIS: Endoanal ultrasound (EAUS) and anal manometry are used in the assessment women with a history of obstetric anal sphincter injury (OASI), both postpartum and in a subsequent pregnancy, to aid counselling regarding mode of delivery (MOD). METHODS: A prospective observational study between 2012 to 2020 was completed. Women were reviewed 3 months postpartum following OASI and in the second half of a subsequent pregnancy. Anorectal symptoms were measured using the validated St Mark's Incontinence Score (SMIS: asymptomatic to mild symptoms = ≤ 4). Anal manometry (incremental maximum squeeze pressure [iMSP: normal = > 20 mmHg]) and EAUS (abnormal = sphincter defect > 1 h in size) were performed. RESULTS: One hundred forty-six women were identified and 67.8% had an anal sphincter defect ≤ 1 h in size postnatally. In those with a defect ≤ 1 h, postpartum mean iMSP and SMIS significantly improved in a subsequent pregnancy (p = 0.04 and p = 0.01, respectively). In women with a defect > 1 h, there was no significant difference between the mean iMSP or SMIS score postnatally compared to a subsequent pregnancy. At both time points, significantly more women had an anal sphincter defect ≤ 1 h and SMIS of ≤ 4 (p = 0.001 and p < 0.001 respectively) compared to those with a defect < 1 h. In addition, significantly more women had an anal sphincter defect ≤ 1 h and iMSP ≥ 20 mmHg (p < 0.001). Overall, out of the 146 women included in this study, 76 (52.1%) with a defect ≤ 1 h also had an iMSP ≥ 20 mmHg and SMIS ≤ 4 at 3 months postpartum. CONCLUSIONS: Women who remain asymptomatic with normal anal manometry and no abnormal sphincter defects on EAUS postnatally do not need to have these investigations repeated in a subsequent pregnancy and can be recommended to have a vaginal delivery. If our protocol was modified, over half of the women in this study could have had their MOD recommendation made in the postnatal period alone.

Outcome of anal symptoms and anorectal function following two obstetric anal sphincter injuries (OASIS)-a nested case-controlled study.

INTRODUCTION AND HYPOTHESIS: Obstetric anal sphincter injury (OASI) is a significant risk factor for developing anal incontinence. It can therefore be hypothesised that recurrent OASI in a subsequent delivery may predispose women to further anal sphincter dysfunction. METHODS: A nested case-controlled study based on data collected prospectively between 2006 and 2019. Women matched for age and ethnicity, with a history of one OASI and no sphincter damage in a subsequent delivery (control) were compared to women sustaining a second OASI. Assessment was carried out using the St Mark's score (SMIS), anorectal manometry and endoanal ultrasound scan (findings quantified using the modified Starck score). RESULTS: Eighty-four women were included and equally distributed between the two groups, who were followed up 12 weeks postnatally. No difference in SMIS scores was found. Maximum resting pressure (MRP, mmHg) and maximum squeeze pressure (MSP, mmHg) were significantly reduced in the study group. Median (IQR) MRP in the study group was 40.0 (31.3-54.0) versus 46.0 (39.3-61.5) in the control group (p = 0.030). Median (IQR) MSP was 73.0 (58.3-93.5) in the study group versus 92.5 (70.5-110.8) (p = 0.006) in the control group. A significant difference (p = 0.002) was found in the modified Starck score between the study group (median 0.0 [IQR 0.0-6.0]) and control group (median 0.0 [IQR 0.0-0.0]). CONCLUSIONS: We have demonstrated that women with recurrent OASI do not have significant anorectal symptoms compared to those with one OASI 12 weeks after delivery, but worse anal sphincter function and integrity. Therefore, on long-term follow-up, symptoms may possibly develop. This information will be useful when counselling women in a subsequent pregnancy.