Is the extent of obstetric anal sphincter injury correlated with the severity of fecal incontinence in the long term?

Management After Obstetric Anal Sphincter Injury: Anorectal Manometry and Symptoms Predict Long-Term Fecal Incontinence

INTRODUCTION

Obstetric anal sphincter injury (OASI) is associated with serious morbidity and reduced quality of life. The role of anorectal manometry (ARM) to guide treatment is unclear. We aimed to define the role of ARM and symptom assessment after OASI in predicting anal incontinence at long-term follow-up.

METHODS

Prospective evaluation of 205 consecutive post-OASI women who underwent baseline ARM and symptom assessment in a tertiary setting was undertaken. Ninety-nine women were available for long-term follow-up (median 6.6 years). Associations between post-OASI ARM testing and short-term and long-term anal incontinence were examined in addition to clinical and obstetric factors.

RESULTS

Fourth degree tears and lower anal resting and squeeze pressures were associated with short-term anal incontinence. Women with anal incontinence at baseline and women with lower anal resting pressure were more likely to suffer from long-term fecal incontinence (FI). A best-fit cutoff value of 59 mm Hg for baseline anal resting pressure predicted long-term FI, and none of the short-term asymptomatic women with an anal resting pressure of >59 mm Hg reported FI at long-term follow-up.

DISCUSSION

Symptoms of anal incontinence and ARM in patients after OASI are both useful to predict subsequent long-term FI with a best-fit cutoff of 59 mm Hg for anal resting pressure. This provides rationale for routine ARM and accurate symptom assessment in all patients after OASI, to identify high-risk groups to follow and treat, and it may assist decision making regarding mode of subsequent obstetric deliveries.

How to Avoid Becoming a Risk Factor of Fecal Incontinence Due to OASIS-A Narrative Review

Third- and fourth-degree anal sphincter injuries are among the most severe traumas women can experience during childbirth, often leading to lifelong continence issues. Despite extensive research, current repair techniques are often inadequate, failing to provide long-term efficiency. The repair of OASIS tends to worsen with time as fecal or anal incontinence increases. This article presents the risk factors for primary repair failure differently from those previously described in the literature, specifically focusing on avoidable risk factors related to obstetricians and surgeons who perform OASIS repair. After reviewing the literature, the following risk areas were identified and described: recurrent OASIS, pitfalls of the current WHO classification, surgical techniques, place in which the repair should be performed, surgical training, factors related to low volumes of patients with grade III-IV injuries, timing of the repair, and failure of primary repair.

Correlation of anorectal symptoms and endoanal ultrasound findings after obstetric anal sphincter injuries (OASIS)

INTRODUCTION

Obstetric anal sphincter injuries (OASIS) predispose to development of anorectal symptoms that affect women's quality of life.

METHODS

A retrospective cohort study was conducted for all women with singleton vaginal deliveries who had a primary OASIS repair and attended the Postpartum Perineal Clinic between July 1st 2017 and December 31st 2020. This study was approved by the Research Ethics Board. The purpose of this study was (1) to determine correlation between endoanal ultrasound (EAUS) findings and anorectal symptoms quantified by the St. Mark's Incontinence Score (SMIS), (2) to determine the incidence of residual anal sphincter defects, and (3) to determine the rate of clinical overdiagnosis of OASIS. Pearson correlation coefficient was used to assess correlation between anorectal symptoms and EAUS findings.

RESULTS

A total of 247 participants with clinical diagnosis of OASIS met the inclusion criteria. A 3rd-degree tear was identified in 126 (51.0%) and 4th-degree tear was identified in 30 (12.1%) participants. In participants with sonographic evidence of OASIS, there was a statistically significant weak positive correlation between the size of residual defect and SMIS for both external anal sphincter (EAS) (r = .3723, p < .0001) and internal anal sphincter (IAS) (r = .3122, p = .0180). Residual defect in the anorectal sphincter of greater than 1 hour (> 30°) in width was present in 64.3% participants with 3rd-degree tear and 86.7% participants with 4th-degree tear. The rate of overdiagnosis was 36.8%.

CONCLUSION

The size of residual defect of EAS and IAS has a weak positive correlation with anorectal symptoms, emphasizing the importance of EAUS for counselling regarding mode of subsequent delivery.

Impact of sex and aging on radiographic and functional parameters of the anal sphincter complex in patients with accidental bowel leakage

AIMS

Treatment outcomes for accidental bowel leakage (ABL) may be influenced by age-related sarcopenia. We sought to determine if thickness of the anal sphincter complex on endoanal ultrasound correlated with function in women and men with ABL and if women demonstrated age-related anal sphincter thinning.

METHODS

Consecutive patients with ABL presenting to our pelvic floor clinic from 2012 to 2017 were included. Clinical data were obtained from medical records. External anal sphincter (EAS), imaged by endoanal ultrasound at proximal, mid and distal locations, and IAS thickness were measured at 12, 3, 6, and 9 o'clock; puborectalis muscle (PRM) was measured at 4, 6, and 8 o'clock; and averaged. Anorectal manometry was conducted when clinically indicated. Data were compared using Mann-Whitney tests and linear regression. Results are reported as mean ± SD or median (IQR).

RESULTS

Women (n = 136) were younger than men (n = 26) (61 ± 13 vs. 67 ± 13 years, p = 0.02). More women than men had pelvic surgery and less had colorectal surgery, spinal disorders, or a history of smoking (p < 0.05). Eighty-two percentage of women had an anal sphincter defect versus 31% of men (p < 0.01). All anal sphincter complex components were thinner in women than men with lower squeeze and resting pressures (p < 0.03), even in nulliparous women. Mean resting pressure was lower in older 6.1 (4.6-7.8) versus younger women 8.3 (5.0-12.9) mmHg, p = 0.04.

CONCLUSIONS

Women, even nulliparous, with ABL demonstrate thinner and weaker anal sphincters than men, Aging correlated with an increase in anal sphincter thickness, suggesting that age-related changes in the intrinsic components of the anal sphincter complex associated with ABL are complex and are not always well demonstrated on endoanal ultrasound.

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.

Incidence and risk factors for secondary failure after acute obstetric sphincter injury repair - an audit of 239 women

AIM

The rate of secondary failure after obstetric sphincter injury repair is unknown, with the literature reporting rates ranging from 0.1% to 53%. We aimed to perform an audit to identify the rate and risk factors for failure of sphincter repair in a cohort of postpartum women using endoanal ultrasound (EAUS) and manometry, assessing the risk factors and impact of these events.

METHOD

Prospective data were collected within a 2 year period from patients who attended the perineal clinic at Eastern Health. Variables of primary repair and presence of postpartum complications were recorded and subsequently analysed.

RESULTS

Of 239 patients with obstetric anal sphincter injury (OASI) included, 100 (41.8%) had EUAS evidence of sphincter defects. Only 20% with secondary repair failure were symptomatic with faecal or flatal incontinence at a mean follow-up of 23.4 months postpartum. Patients with secondary repair failure had lower anal resting (p = 0.006) and maximum squeeze pressures compared with patients with intact repairs (p < 0.001). In terms of variables that were investigated, namely location, operator hierarchy, type of repair and material used, none had a statistically significant correlation with secondary repair failure of OASI. Postpartum complications had an overall incidence of 12.7%, and those with any complication were found to have an increased rate of secondary failure of repair (p = 0.157).

CONCLUSION

Using EAUS to confirm secondary failure of repair, incidence was 41.4% in this cohort. There were no identifiable modifiable variables that reduced the risk of secondary failure of repair. Further prospective research with increased sample size and longer follow-up periods is required to assess the validity of the findings.

Short and long term results of anatomical reconstruction of perineal body and sphincter complex in obstetric anal sphincter injuries

OBJECTIVES

The effective way to reduce the risk of fecal incontinence (FI) in primary repaired obstetric anal sphincter injuries (OASIS) patients is to accurately detect the injury and provide complete anatomical reconstruction. The aim of the study was to evaluate the short-term and long-term results of OASIS cases that were diagnosed by an experienced surgical team and whose perineal body and anal sphincters were reconstructed separately.

MATERIAL AND METHODS

Sixteen patients that required consultations due to anal sphincter damage during vaginal delivery and underwent anatomical reconstruction due to Grade 3c and Grade 4 sphincter damage between 2007 and 2019 were included in the study. These cases were divided into three groups [Group 1 (≤12 months), Group 2 (12-60 months), Group 3 (≥60 months)] according to the time elapsed until anal manometry, and incontinence questionnaires were conducted in the postoperative period. Recto-anal inhibitory reflex (RAIR), mean resting (IB) and squeezing (SB) pressures were measured by anal manometry. Anal incontinence (AI) and FI rates were determined by questionnaires. Anal sphincter damage repair techniques (overlapping, end-to-end) were determined. These parameters were compared between the three groups.

RESULTS

Mean age of the patients was 27.5 (16-35) years. Six (37.5%) patients had Grade 3c, while 10 (62.5%) had Grade 4 injury. The overall mean RP and SP were 35 (26-56) mmHg and 67 (31-100) mmHg, respectively. Mean RP and SP were 46/67 mmHg, 33.5/75.5 mmHg, and 37.5/70.5 mmHg in Groups 1, 2, and 3 respectively. There was no difference between the three groups in terms of mean RP and SP (p= 0.691, p= 0.673). The rate of AI and FI in all patients were 18.75% and 12.5%, respectively while the rate of severe AI incontinence was 6%. Severe AI was observed in 1 (16.7%) case in Group 1, mild AI was observed in 1 (25%) case in group 2, and in 1 (16.7%) case in Group 3. RAIR was positive in all patients. In Group 1, 5 (83.3%) patients underwent overlapping repair, and in Group 3, 6 (100%) patients underwent end-to-end repair. This difference was statistically significant (p= 0.011).

CONCLUSION

In vaginal births, evaluation of anal sphincter damage, determination of perineal body structures and anal sphincters separately and performing anatomical reconstruction when needed significantly reduce the rate of FI in the short and long term.

Association between birth weight and head circumference and obstetric anal sphincter injury severity

OBJECTIVE

To identify risk factors for increasing severity of OASI and evaluate its possible correlation with two known risk factors-birth weight (BW) and neonatal head circumference (HC).

METHODS

We performed a retrospective cohort study at a university affiliated hospital between 2003 and 2019. We compared five groups of patients - according to presence and degree of perineal laceration - 3a, 3b, 3c and 4 and patients without OASI. Additionally, four parameters were defined to assess their relation to the severity of OASI: (1) BW ≥ 90th and HC < 90th percentiles; (2) BW < 90th and HC ≥ 90th percentile; (3) BW and HC ≥ 90th percentile and (4) BW and HC < 90th percentiles.

RESULTS

During the study period, 150,221 deliveries were evaluated. Parturients were allocated according to OASI severity - 455 patients had a 3rd (3a, 3b or 3c) or 4th degree perineal tear, while 110,966 patients had no OASI. Allocation to subgroups according to offspring anthropomorphic measures showed that as fetal size parameters increased, the rate of more severe tears increased, particularly in women delivering neonates with HC ≥ 90th percentile. Multinomial regression analysis was performed for each 3rd degree OASI subgroup. This analysis demonstrated the odds for OASI gradually increase with tear severity for BW ≥ 90th percentile and the combined BW and HC ≥ 90th percentile parameters, as compared with neonates with HC and BW < 90th percentile.

CONCLUSIONS

Birth weight and head circumference above the 90th percentile are correlated with increased degree of OASI severity.

Language barrier as a risk factor for obstetric anal sphincter injury - A case-control study

INTRODUCTION

The incidence of grade 3-4 perineal tears, also known as obstetric anal sphincter injury (OASI), is reported to be between 0.5 and 2.5%. Beyond the medico-economic burden, the consequences of OASI on a woman's emotional, psychological, sexual, and physical wellbeing are considerable. Among the various risk factors of OASI, few data are available about the impact of a language barrier on its incidence.

MATERIAL AND METHODS

We conducted a case-control study to evaluate the effect of language barriers on the risk of OASI comparing 171 women with OASI and 163 matched controls. The matched criteria included ethnicity, age, previous vaginal delivery, delivery mode, prophylactic episiotomy and birthweight. Patients' characteristics were compared and crude ORs and 95% CIs estimated using unadjusted logistic models. Multivariate analysis was performed with recognized potential confounders.

RESULTS

All of the cases had grade 3 tears. Language barrier was a determinant factor of OASI with an OR of 3.32 [1.36-8.90], p = 0.01. Other risk factors were occipito-posterior delivery, African origin and prolonged labor duration (OR 6.33, 95% CI: 2.04-27.78, p = 0.004, OR 1.85, 95% CI: 1.08-3.19, p = 0.03 and OR 1.03, 95% CI: 1.01-1.05, p = 0.004, respectively).

CONCLUSION

Our data suggest that language barrier is an independent risk factor of OASI. Physicians and midwives should attempt to identify patients with a language barrier during prenatal visits. Education about simple terms used during delivery could decrease the incidence of this complication.

Can ultrasound 10 days after obstetric anal sphincter injury predict anal incontinence at long-term follow-up?

INTRODUCTION AND HYPOTHESIS

The objective was to investigate whether endoanal ultrasound (EAUS) performed 10 days after a primary repaired obstetric anal sphincter injury (OASIS) can predict the severity of anal incontinence (AI) in the long term.

METHODS

This prospective cohort study included women with a primary repaired 3b-degree tear, 3c-degree tear or fourth-degree tear at Aarhus University Hospital, Denmark, from 1 September 2010 to 31 May 2011. Clinical assessment and EAUS were performed on day 2, day 10, and day 20 after delivery. Functional outcomes were assessed using a questionnaire at the time of all clinical visits and at the long-term follow-up, 7 years after delivery. AI was graded according to the Wexner score and EAUS defects were graded according to the Starck score.

RESULTS

Ninety-six out of 99 women consented to participate. Five women had a secondary sphincter repair and were subsequently excluded from follow-up. Fifty-seven women underwent both EAUS 10 days after delivery and answered the long-term follow-up questionnaire. Median follow-up time was 7.7 years (IQR 7.4-7.8). Mean Wexner score was 4.4 ± 4.8 10 days after delivery and 2.5 ± 2.8 at follow-up; thus, the Wexner score improved over time (p = 0.01). Ultrasound sphincter defects were found in 82.6% of the women. Mean Starck score was 3.0 ± 1.8. The risk of AI was 0% (95% CI 0.0-30.8) if the Starck score was 0. No correlation was found between the Starck score and the Wexner score at follow-up.

CONCLUSIONS

We found that performing EAUS in the puerperium following OASIS has limited value in predicting long-term AI.

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.

Correlation of anorectal manometry measures to severity of fecal incontinence in patients with anorectal malformations - a cross-sectional study

Anorectal malformations (ARM) are a spectrum of anomalies of the rectum and anal canal affecting 1 in 2500 to 5000 live births. Functional problems are common and related to the type of ARM and associated malformations. We aimed to evaluate the results of Three-dimensional High Resolution Anorectal Manometry (3D-HRAM) in long-term follow-up after surgical correction of ARM with special reference to fecal incontinence. Twenty-one patients with anorectal malformations and primary repair at our center consented to participate in the study. Pressures of the anal sphincter muscles and defects were addressed by 3D-HRAM. Fecal incontinence and disease-specific quality of life were evaluated by the Fecal Incontinence Quality of Life score and Wexner incontinence score respectively. The study was approved by the Committee in Health Research Ethics and the Danish Data Protection Agency. Median age was 22(12-31) years and 13(67%) participants were females. Sphincter defect was present in 48% (N = 10) of participants. Participants with sphincter defects had significant higher Wexner score and size of sphincter defects and mean anal squeeze pressure were correlated to Wexner score. Participants with or without sphincter defects did not differ on manometry parameters including resting anal and squeeze pressure or disease-specific quality of life. In a study of the long-term outcome after repair of anorectal malformations we found a higher Wexner incontinence score in the presence of an anal sphincter defect and the size of the defect and mean anal squeeze pressure were correlated to the Wexner incontinence score.