Incontinence after primary repair of obstetric anal sphincter tears is related to relative length of reconstructed external sphincter: a case-control study

Irritable bowel syndrome worsens faecal incontinence after primary repair of major obstetric anal sphincter injuries

AIM

Obstetric anal sphincter injuries (OASIS) occur in approximately 3%-6% of vaginal deliveries and are the leading risk factor for late-onset faecal incontinence, which is an underdiagnosed pathology. The aim of this work was to use a validated scoring system to quantify the effect of irritable bowel syndrome (IBS) on the severity of faecal incontinence symptoms after primary repair of major OASIS (Grade IIIb-IV).

METHOD

A prospective cohort study was performed on all women who underwent primary repair of major OASIS over a 6-year period. They were assessed with ultrasonography within 12 weeks. Two control groups (who did not have OASIS) were women who underwent elective caesarean section and primigravid women. Questionnaires were sent at least 12 months after delivery, or at first consultation for primigravids, which generated the main outcome measures: Cleveland Clinic faecal incontinence severity scores and the presence of IBS based on Rome III criteria.

RESULTS

There was a total of 211 patients included in the three groups and the mean follow-up time was 26 months after sphincter repair. Ultrasonographic sphincter defects were detected in 37% but did not affect the faecal incontinence score (p = 0.47), except in patients with IBS. Within each group, patients with IBS had significantly worse faecal incontinence than those without. Women with both OASIS and IBS had the most severe faecal incontinence scores.

CONCLUSION

OASIS has a limited negative effect on faecal incontinence, independent of whether residual ultrasonographic sphincter defects are present. However, the presence of IBS has a significant compounding effect on faecal incontinence in OASIS patients. The effect of IBS on faecal incontinence is also notable in caesarean section patients and primigravids, suggesting that IBS is an independent risk-factor that should have its place in predelivery assessment and counselling.

Obstetric anal sphincter injury (OASI) in the presence of an intact perineum

Obstetric anal sphincter injury (OASI) in the absence of concurrent injury to the perineal skin is not a common diagnosis. A primiparous woman delivered a healthy male infant by spontaneous vertex delivery. At time of delivery, a compound presentation of the fetal hand with the head was noted. Initial examination revealed a presumed second-degree tear; however, a small laceration above the anal verge was noted, which on exploration revealed a perineal injury through the anal sphincter complex. In the operating theatre, the perineal skin was incised to reveal a 3c OASI, which was repaired appropriately. While atypical OASI has been reported previously, this specific injury has never been described in detail in the literature. Awareness of atypical perineal injuries is needed and while careful perineal examination is required in all cases, this is especially important where the perineal skin appears intact to ensure appropriate diagnosis of any concurrent OASI.

Underdiagnosis of internal anal sphincter trauma following vaginal delivery

OBJECTIVE

Damage to the anal sphincter during childbirth remains the leading cause of fecal incontinence in women. Defects in the internal (IAS) or external anal sphincter, alongside symptoms and sphincter tone, will generally dictate the suggested mode of delivery in any successive pregnancy. This study aimed to examine using endoanal ultrasonography the prevalence of IAS damage in women referred with Grade-3a or -3b obstetric anal sphincter injury (OASI) in a tertiary-referral perineal clinic.

METHODS

This was a retrospective observational study of all women referred to a tertiary-referral perineal clinic after primary repair of OASI (Grade 3a-c, 4) diagnosed for the first time following vaginal delivery between January 2016 and December 2019, inclusive. Women were assessed using the Wexner bowel continence questionnaire, digital examination of sphincter tone and endoanal ultrasound. Injuries in each sphincter were classified as a scar (≤ 30°) or defect (> 30-90° or > 90°) on endoanal imaging in the axial plane.

RESULTS

In total, 615 women were referred following primary repair of OASI. Sonographic evidence of damage to the IAS was seen in 9.1% (46/506) of women diagnosed with a Grade-3a/3b injury. In women referred with a Grade-3a/3b tear, symptom scores were statistically higher (P = 0.025) in those with an IAS defect > 30° compared to those with an intact or scarred IAS, although the median score was zero in both groups. The proportion of women in each group with severe symptoms (score > 9) was similar (2.6% vs 6.5%; P = 0.148). Among women referred with a Grade-3a/3b tear, sphincter tone was reduced more frequently in those with a defect of the IAS than in those with an intact or scarred IAS (52.2% vs 11.7%; odds ratio, 8.14 (95% CI, 4.26-15.67); P < 0.001). Regardless of the reason for referral, women with reduced sphincter tone on rectal examination were four times as likely to have had an IAS defect > 30° than were those with normal resting tone (risk ratio, 4.58 (95% CI, 3.25-6.45); P < 0.001).

CONCLUSIONS

One in 11 women diagnosed with a Grade-3a or -3b tear have evidence of damage to their IAS on endoanal ultrasound. Damage to this muscle is linked to fecal incontinence in women and can have a significant impact on the planning of any future deliveries. This study highlights the importance of established perineal clinics with access to ultrasound. Nonetheless, if reduced sphincter tone is felt on rectal examination, a clinician should have a high index of suspicion for an occult IAS injury. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Anal Sphincter Length as Determined by 3-Dimensional Endoanal Ultrasound and Anal Manometry: A Study in Healthy Nulliparous Women

OBJECTIVES

The normal female external anal sphincter (EAS) is shorter anteriorly than laterally and posteriorly. Furthermore, the thickness of the very proximal part of the circular EAS is thinner than 50% of the lateral and posterior EAS thickness. The extent of these features is not fully explored. The aim of this prospective study was to assess the normal anal sphincter with 3-dimensional (3D) endoanal ultrasound (EAUS) and to relate 3D EAUS length measurements to sphincter length determined by anal manometry.

METHODS

Healthy premenopausal nulliparous women underwent anal manometry and 3D EAUS examinations. Two experienced colorectal surgeons independently assessed all scans, blinded to any patient data.

RESULTS

A total of 43 women were included. Four scans were incomplete and excluded from the analysis. Interobserver agreement was fair to very good for the various length measurements. The mean length from the distal border of the puborectal muscle to the very proximal border of the anterior EAS (the anterior gap) was 4.4 (95% confidence interval, 3.9-4.9) mm, whereas the length to the level where the anterior EAS thickness was at least 50% of the lateral and posterior EAS thickness was 7.2 (95% confidence interval, 6.5-7.9) mm. Manometric sphincter length at rest did not correlate with any 3D EAUS length measurements.

CONCLUSIONS

In the normal anterior female anal canal, the EAS is not present or appears with less than 50% of the thickness of the lateral and posterior EAS for the first 7.2 mm below the distal border of the puborectal muscle.

Establishing a peripartum perineal trauma clinic: a narrative review

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injury (OASI) is not rare, and its consequences are multiple and potentially severe, especially for young women. Some dedicated perineal clinics have been established to improve the management of OASI. Despite their obvious importance, these specific clinics are underrepresented and underdeveloped. The objectives of this review are to explore various options for developing a peripartum perineal clinic and to compare the different practices regarding the mode of delivery for subsequent pregnancies after an OASI.

METHODS

This narrative review covers information from patients' questionnaires specific to anal incontinence, anal physiology assessment, pelvic floor and anal sphincter imaging, and the arguments for choosing the mode of delivery after an OASI.

RESULTS

This review highlights the extensive range of practices regarding the delivery mode after an OASI throughout national professional organizations and experienced perineal clinics.

CONCLUSION

This review summarizes the different choices in developing a perineal clinic to facilitate their development in promoting health care and education specific for peripartum women concerning the perineal consequences of delivery for obstetrician-gynaecologists, family doctors, and residents.

Risk of obstetric anal sphincter injuries (OASIS) and anal incontinence: A meta-analysis

BACKGROUND

Obstetric anal sphincter injuries (OASIS) are the commonest cause of anal incontinence in women of reproductive age. We determined the risk of anal sphincter defects diagnosed by ultrasound, and the risk of anal incontinence in (i) all women who deliver vaginally, (ii) in women without clinical suspicion of OASIS, and (iii) after primary repair of sphincter injury, by systematic review.

METHODS

We searched major databases until June 2018, without language restrictions. Random effects meta-analysis was used to obtain pooled estimates of ultrasound diagnosed OASIS and risk of anal incontinence symptoms at various time points after delivery, and of persistent sphincter defects after primary repair. We reported the association between ultrasound diagnosed OASIS and anal incontinence symptoms using relative risk (RR) with 95 % CI.

RESULTS

We included 103 studies involving 16,110 women. Of all women who delivered vaginally, OASIS were diagnosed on ultrasound in 26 % (95 %CI, 21-30, I² = 91 %), and 19 % experienced anal incontinence (95 %CI, 14-25, I² = 92 %). In women without clinical suspicion of OASIS (n = 3688), sphincter defects were observed in 13 % (10-17, I² = 89 %) and anal incontinence experienced by 14 % (95 % CI: 6-24, I² = 95 %). Following primary repair of OASIS, 55 % (46-63, I² = 98 %) of 7549 women had persistent sphincter defect with 38 % experiencing anal incontinence (33-43, I² = 92 %). There was a significant association between ultrasound diagnosed OASIS and anal incontinence (RR 3.74, 2.17-6.45, I² = 98 %).

INTERPRETATION

Women and clinicians should be aware of the high risk for sphincter defects following vaginal delivery even when clinically unsuspected. This underlines the need of careful and systematic perineal assessment after birth to mitigate the risk of missing OASIS. We also noted a high rate of persistent defects and symptoms following primary repair of OASIS. This dictates the need for provision of robust training for clinicians to achieve proficiency and sustain competency in repairing OASIS.

Do pelvic floor muscle exercises reduce postpartum anal incontinence? A randomised controlled trial

OBJECTIVE

To evaluate the effect of pelvic floor muscle exercises (PFME) for postpartum anal incontinence (AI).

DESIGN

A parallel two-armed randomised controlled trial stratified on obstetrical anal sphincter injury with primary sphincter repair and hospital affinity.

SETTING

Ano-rectal specialist out-patient clinics at two hospitals in Norway.

POPULATION

One hundred and nine postpartum women with AI at baseline.

METHODS

The intervention group received 6 months of individual physiotherapy-led PFME and the control group written information on PFME. Changes in St. Mark's scores and predictors of post-intervention AI were assessed by independent samples t-tests and multiple linear regression analyses, respectively. The study was not blind.

MAIN OUTCOME MEASURES

The primary outcome measure was change in AI symptoms on the St. Mark's score from baseline to post-intervention. Secondary outcome measures were manometry measures of anal sphincter length and strength, endoanal ultrasound (EAUS) defect score and voluntary pelvic floor muscle contraction.

RESULTS

There was a significant difference in the reduction of St. Mark's scores from baseline to post-intervention in favour of the PFME group (-2.1 versus -0.8 points, P = 0.040). No differences in secondary outcome measures were found between groups. Baseline St. Mark's, PFME group affinity and EAUS defect score predicted post-intervention St. Mark's score in the imputed intention-to-treat analyses. The analysis on un-imputed data showed that women performing weekly PFME improved their AI scores more than women in the control group did.

CONCLUSIONS

Our results indicate that individually adapted PFME reduces postpartum AI symptoms.

TWEETABLE ABSTRACT

Performing regular pelvic floor muscle exercises may be an effective treatment for postpartum anal incontinence.

Factors predicting a failed primary repair of obstetric anal sphincter injury

INTRODUCTION

The success of the primary repair of obstetric anal sphincter injury (OASI) is paramount in maintaining adequate fecal continence after childbirth. The factors determining the success or failure of primary repair are unclear. The aim of this study is to investigate modifiable factors determining the success or failure of the primary sphincter repair after OASI.

MATERIAL AND METHODS

Sixty women with OASI were investigated by endoanal ultrasound or magnetic resonance imaging, and with the Wexner incontinence questionnaire. Based on the findings, the women were divided in two groups; successful primary repair group (n = 41) and failed primary repair group (n = 19).

RESULTS

The primary repair failed in 31.7% of the tears. These included more tears repaired by less experienced personnel (p < 0.001) and more repairs performed during on-call hours (p = 0.039) than in the successful primary repair group. Significantly more pain medication was used in the failed group (p = 0.003), and the use of antibiotics and laxatives after the repair was more common in the successful group (p < 0.001). Sphincter injuries were repaired using the overlapping suture technique in 95.1% of the repairs in the successful group compared with 47.4% in the failed group (p = 0.03). The mean (SD) Wexner score was significantly higher in the failed group [5.92 (4.1) vs. 1.88 (4.2), p < 0.001], in agreement with the findings on endoanal ultrasound.

CONCLUSIONS

Postpartum perineal tears should be evaluated by personnel familiar with the diagnosis and repair of OASI. Delaying the primary repair until next morning is recommended if experienced personnel are unavailable during on-call hours.