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

Caesarean section and anal incontinence in women after obstetric anal sphincter injury: A systematic review and meta-analysis

BACKGROUND

Approximately 50% women who give birth after obstetric anal sphincter injury (OASI) develop anal incontinence (AI) over their lifetime.

OBJECTIVE

To evaluate current evidence for a protective benefit of planned caesarean section (CS) to prevent AI after OASI.

SEARCH STRATEGY

MEDLINE/PubMed, Embase 1974-2024, CINAHL and Cochrane to 7 February 2024 (PROSPERO CRD42022372442).

SELECTION CRITERIA

All studies reporting outcomes after OASI and a subsequent birth, by any mode.

DATA COLLECTION AND ANALYSIS

Eighty-six of 2646 screened studies met inclusion criteria, with nine studies suitable to meta-analyse the primary outcome of 'adjusted AI' after OASI and subsequent birth. Subgroups: short-term AI, long-term AI, AI in asymptomatic women.

SECONDARY OUTCOMES

total AI, quality of life, satisfaction/regret, solid/liquid/flatal incontinence, faecal urgency, AI in women with and without subsequent birth, change in AI pre- to post- subsequent birth.

MAIN RESULTS

There was no evidence of a difference in adjusted AI after subsequent vaginal birth compared with CS after OASI across all time periods (OR = 0.92, 95% CI 0.72-1.20; 9 studies, 2104 participants, I2 = 0% p = 0.58), for subgroup analyses or secondary outcomes. There was no evidence of a difference in AI in women with or without subsequent birth (OR = 1.00 95% CI 0.65-1.54; 10 studies, 970 participants, I2 = 35% p = 0.99), or pre- to post- subsequent birth (OR = 0.79 95% CI 0.51-1.25; 13 studies, 5496 participants, I2 = 73% p = 0.31).

CONCLUSIONS

Due to low evidence quality, we are unable to determine whether planned caesarean is protective against AI after OASI. Higher quality evidence is required to guide personalised decision-making for asymptomatic women and to determine the effect of subsequent birth mode on long-term AI outcomes.

A sensorised surgical glove to improve training and detection of obstetric anal sphincter injury: A preclinical study on a pig model

OBJECTIVE

To create a sensorised surgical glove that can accurately identify obstetric anal sphincter injury to facilitate timely repair, reduce complications and aid training.

DESIGN

Proof-of-concept.

SETTING

Laboratory.

SAMPLE

Pig models.

METHODS

Flexible triboelectric pressure/force sensors were mounted onto the fingertips of a routine surgical glove. The sensors produce a current when rubbed on materials of different characteristics which can be analysed. A per rectum examination was performed on the intact sphincter of pig cadavers, analogous to routine examination for obstetric anal sphincter injuries postpartum. An anal sphincter defect was created by cutting through the vaginal mucosa and into the external anal sphincter using a scalpel. The sphincter was then re-examined. Data and signals were interpreted.

MAIN OUTCOME MEASURES

Sensitivity and specificity of the glove in detecting anal sphincter injury.

RESULTS

In all, 200 examinations were performed. The sensors detected anal sphincter injuries in a pig model with sensitivities between 98% and 100% and a specificity of 100%. The current produced when examining an intact sphincter and sphincter with a defect was significantly different (p < 0.001).

CONCLUSION

In this preliminary study, the sensorised glove accurately detected anal sphincter injury in a pig model. Future plans include its clinical translation, starting with an in-human study on postpartum women, to determine whether it can accurately detect different types of obstetric anal sphincter injury in vivo.

Is vaginal birth after cesarean section a risk factor for obstetric anal sphincter injury?

OBJECTIVE

To investigate whether women undergoing their first vaginal delivery after a previous cesarean section (secundiparous) are at increased risk for obstetric anal sphincter injury (OASI) compared with primiparous women.

METHODS

A retrospective cohort study of 85 428 women who delivered vaginally over a 10-year period in a single tertiary medical center. Incidence of OASI, risk factors, and clinical characteristics were compared between primiparous women who delivered vaginally and secundiparous women who underwent their first vaginal birth after cesarean section (VBAC). A multivariable logistic regression analysis was used to study the association between VBAC and OASI.

RESULTS

Overall, 36 250 primiparous and 1602 secundiparous women were enrolled, 309 of whom had OASI. The rates of OASI were similar among secundiparous women who had VBAC and primiparous women who underwent vaginal delivery (15 [0.94%] vs 294 [0.81%], P = 0.58). The proportions of third- and fourth-degree tears were also similar among secundiparous and primiparous women who experienced OASI (87% vs 91.5%, and 13% vs 8.5%, respectively, P = 0.68). Furthermore, the rates of OASI were similar in both study groups, although secundiparous women who underwent VBAC had higher rates of birth weights exceeding 3500 g (414 [25.8%] vs 8284 [22.8%], P = 0.016), and higher rates of vacuum-assisted deliveries (338 [21%] vs 6224 [17.2%], P < 0.001). A multivariate logistic regression analysis failed to establish a statistically significant association between VBAC and OASI (odds ratio 0.672, 95% confidence interval 0.281-1.61, P = 0.37).

CONCLUSIONS

No increased risk for OASI was found in secundiparous women who underwent VBAC compared with primiparous women at their first vaginal birth.

Occurrence and risk factors for second-degree perineal tears: A prospective cohort study using a detailed classification system

BACKGROUND

The amount of tissue trauma within second-degree perineal tears varies widely. Therefore, subcategorization of second-degree tears and a better understanding of their occurrence and risk factors are needed. The aim of this study was to assess the occurrence of perineal tears when second-degree tears were subcategorized. Furthermore, we aimed to assess the association between variables related to perineal anatomy and other potential risk factors, with second-degree tear subcategories.

METHODS

This prospective cohort study included 880 primiparous and multiparous women giving birth to one child vaginally. Perineal tears were categorized using the classification system recommended by the Royal College of Obstetricians and Gynaecologists. In addition, second-degree tears were subcategorized as 2A, 2B, or 2C according to the percentage of damage to the perineal body. Selected variables related to perineal anatomy were as follows: length of genital hiatus; perineal body length; and previous perineal trauma. Risk factors for second-degree tear subcategories were analyzed using a multinominal regression model.

RESULTS

Perineal tears occurred as follows: first-degree: 35.6% (n = 313), 2A: 16.3% (n = 143), 2B: 9.1% (n = 80), 2C: 6.6% (n = 58), and third- or fourth-degree: 1.6% (n = 14). In total, 169/880 participants underwent an episiotomy. When episiotomies were excluded, the risk for 2B, or 2C tears increased with smaller genital hiatus, larger perineal body, previous perineal trauma, primiparity, higher gestational age, instrumental vaginal delivery and fetal presentation other than occiput anterior.

CONCLUSION

The occurrence of second-degree tear subcategories was 16.3% for 2A tears, 9.1% for 2B tears, and 6.6% for 2C tears. Factors related to perineal anatomy increased the odds for experiencing a second-degree tear in a more severe subcategory.

Complications 8 weeks after an obstetric second-degree perineal laceration in relation to body mass index

INTRODUCTION AND HYPOTHESIS

How body mass index (BMI) affects pelvic floor function after a second-degree perineal laceration is unknown. The hypothesis of this study is that pelvic floor dysfunction and complications after an obstetric second-degree perineal laceration are more common in women with a higher BMI 8 weeks postpartum.

METHODS

This register-based cohort study includes 10,876 primiparous women with an obstetric second-degree perineal laceration between 2014 and 2021. Data were retrieved from the Swedish Perineal Laceration Registry. Outcomes in relation to maternal BMI were urinary incontinence (UI), anal incontinence (AI) and common complications attributable to the laceration. Uni- and multivariate logistic regressions were used for comparison between normal weight (BMI < 24.9, reference), overweight (25.0-29.9) and obese (≥ 30) women.

RESULTS

Multivariate analyses showed an increased risk for UI in both overweight and obese women compared to normal-weight women 8 weeks after a second-degree perineal laceration with an adjusted odds ratio (aOR) of 1.21 (CI 1.02-1.44) and 1.27 (CI 1.13-1.58) respectively. Overweight and obese women had a decreased risk for AI (aOR 0.81, CI 0.68-0.96; aOR 0.72, CI 0.57-0.90 respectively) compared with normal-weight women. No significant differences were found in the univariate analyses over BMI strata concerning complications after perineal laceration.

CONCLUSIONS

Primiparous overweight and obese women report less AI and more UI than normal-weight women 8 weeks after a second-degree perineal laceration. No differences were found regarding complications. These findings are new and merit further study to find potential preventive factors and interventions after a second-degree perineal laceration.

Anal incontinence following obstetric anal sphincter injury: Is there a difference between subtypes? A systematic review

AIMS

Obstetric anal sphincter injury (OASI) is associated with long-term anal incontinence (AI). We aimed to address the following questions: (a) are women with major OASI (grade 3c and 4) at higher risk of developing AI when compared to women with minor OASI (grade 3a and 3b)? (b) is a fourth-degree tear more likely to cause AI over a third-degree tear?

METHODS

A systematic literature search from inception until September 2022. We considered prospective and retrospective cohort studies, cross-sectional and case-control studies without language restrictions. The quality was assessed by the Newcastle-Ottawa Scale and the Joanna Briggs Institute critical appraisal checklist. Risk ratios (RRs) were calculated to measure the effect of different grades of OASI.

RESULTS

Out of 22 studies, 8 were prospective cohort, 8 were retrospective cohort, and 6 were cross-sectional studies. Length of follow-up ranged from 1 month to 23 years, with the majority of the reports (n = 16) analysing data within 12-months postpartum. Third-degree tears evaluated were 6454 versus 764 fourth-degree tears. The risk of bias was low in 3, medium in 14 and high in 5 studies, respectively. Prospective studies showed that major tears are associated with a twofold risk of AI for major tears versus minor tears, while retrospective studies consistently showed a risk of fecal incontinence (FI) which was two- to fourfold higher. Prospective studies showed a trend toward worsening AI symptoms for fourth-degree tears, but this failed to reach statistical significance. Cross-sectional studies with long-term (≥5 years) follow-up showed that women with fourth-degree tear were more likely to develop AI, with an RR ranging from 1.4 to 2.2. Out of 3, 2 retrospective studies showed similar findings, but the follow-up was significantly shorter (≤1 year). Contrasting results were noted for FI rates, as only 5 out of 10 studies supported an association between fourth-degree tear and FI.

CONCLUSIONS

Most studies investigate bowel symptoms within few months from delivery. Data heterogeneity hindered a meaningful synthesis. Prospective cohort studies with adequate power and long-term follow-up should be performed to evaluate the risk of AI for each OASI subtype.