How comparable is clinical grading of obstetric anal sphincter injury with that determined by four-dimensional translabial ultrasound?

4D transperineal ultrasound: feedback for good obstetric anal sphincter injuries reparation

BACKGROUND

Obstetric anal injury is the main risk factor for traumatic anal, faecal and flatus, incontinence in women in reproductive age. Its recognition and good reparation are crucial for long term outcomes.

CASE REPORT

We report a case of a nulliparous woman who reported a fourth-degree perineal tear after delivery. The obstetric anal sphincter injury was repaired and a four-dimensional transperineal ultrasound was performed after reparation and then one and three months after discharge. The woman did not experience any incontinence and no points of discontinuity were observed at tomographic ultrasound imaging reconstruction. In this case, 4D-TPUS was a tool in the obstetrician's hands to evaluate the surgical success of OASIS repair, which requires some expertise.

CONCLUSIONS

4D-TPUS ultrasound is useful and reliable during immediate puerperium and in the subsequent follow-up, giving positive feedback on the correct positioning of the stiches and on a good healing process. Further studies are needed to demonstrate this usefulness in the operators training and for improving their surgical skills.

Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta-analysis

OBJECTIVES

The primary objective was to perform a systematic review of predictive factors for obstetric anal sphincter injury (OASI) occurrence at first vaginal delivery, with the diagnosis made by ultrasound (US-OASI). The secondary objective was to report on incidence rates of sonographic anal sphincter (AS) trauma, including trauma that was not clinically reported at childbirth, among the studies providing data for our primary objective.

METHODS

We conducted a systematic search of MEDLINE, EMBASE, Web of Science, CINAHL, The Cochrane Library and ClinicalTrials.gov databases. Both observational cohort studies and interventional trials were eligible for inclusion. Study eligibility was assessed independently by two authors. Random-effects meta-analyses were performed to pool effect estimates from studies reporting on similar predictive factors. Summary odds ratio (OR) or mean difference (MD) is reported with 95% CI. Heterogeneity was assessed using the I2 statistic. Methodological quality was assessed using the Quality in Prognosis Studies tool.

RESULTS

A total of 2805 records were screened and 21 met the inclusion criteria (16 prospective cohort studies, three retrospective cohort studies and two interventional non-randomized trials). Increasing gestational age at delivery (MD, 0.34 (95% CI, 0.04-0.64) weeks), shorter antepartum perineal body length (MD, -0.60 (95% CI, -1.09 to -0.11) cm), labor augmentation (OR, 1.81 (95% CI, 1.21-2.71)), instrumental delivery (OR, 2.13 (95% CI, 1.13-4.01)), in particular forceps extraction (OR, 3.56 (95% CI, 1.31-9.67)), shoulder dystocia (OR, 12.07 (95% CI, 1.06-137.60)), episiotomy use (OR, 1.85 (95% CI, 1.11-3.06)) and shorter episiotomy length (MD, -0.40 (95% CI, -0.75 to -0.05) cm) were associated with US-OASI. When pooling incidence rates, 26% (95% CI, 20-32%) of women who had a first vaginal delivery had US-OASI (20 studies; I2  = 88%). In studies reporting on both clinical and US-OASI rates, 20% (95% CI, 14-28%) of women had AS trauma on ultrasound that was not reported clinically at childbirth (16 studies; I2  = 90%). No differences were found in maternal age, body mass index, weight, subpubic arch angle, induction of labor, epidural analgesia, episiotomy angle, duration of first/second/active-second stages of labor, vacuum extraction, neonatal birth weight or head circumference between cases with and those without US-OASI. Antenatal perineal massage and use of an intrapartum pelvic floor muscle dilator did not affect the odds of US-OASI. Most (81%) studies were judged to be at high risk of bias in at least one domain and only four (19%) studies had an overall low risk of bias.

CONCLUSION

Given the ultrasound evidence of structural damage to the AS in 26% of women following a first vaginal delivery, clinicians should have a low threshold of suspicion for the condition. This systematic review identified several predictive factors for this. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Assessing Obstetric Anal Sphincter Injuries: A Comparison of Exoanal and Endoanal Ultrasound

OBJECTIVES

To explore the differences in assessing obstetric anal sphincter injuries (OASI) between transperineal ultrasound (TPUS) and endoanal ultrasound (EAUS) and test relationships between ultrasound findings and anal incontinence (AI) symptoms.

METHODS

A group of 196 women with a history of vaginal delivery was recruited. OASI was detected in a set of 5 slices by EAUS and 8 slices by TPUS. OASI grading was performed on TPUS rules and EAUS rules. A "significant sphincter defect" was diagnosed by TPUS and EAUS using "2/3 rules." Symptoms of AI were determined using the St Mark's Incontinence Score (SMIS). Ultrasound findings were compared between the two methods and correlated with symptoms.

RESULTS

Of 196 women, 29 (14.8%) suffered from AI with a mean SMIS of 12.1 ± 4.5, and 70 (35.7%) women with a mean age of 57 years had suspected OASI on imaging. Twenty-one (10.7%) "significant defects" were diagnosed by TPUS and 24 (12.2%) by EAUS. OASI Grades on TPUS had good agreement with EAUS rules (k = 0.70, P < .001). Logistic regression analysis showed that OASI Grade on imaging and "significant sphincter defects" seen on both forms of imaging were associated with AI symptoms. The odds ratio was 46 and 38 for "significant defects" on TPUS and EAUS, and 14 and 7 for OASI 3b+ on TPUS and EAUS in predicting AI, respectively.

CONCLUSIONS

"Significant defects" diagnosed by EAUS or TPUS and OASI Grade 3b+ predict AI symptoms. The diagnostic performance of endoanal and exoanal ultrasound (EAUS and TPUS) appear to be very similar.

Is posterior compartment prolapse associated with anal incontinence?

OBJECTIVE

It has been claimed that manifestations of posterior compartment prolapse, such as rectocele, enterocele and intussusception, are associated with anal incontinence (AI), but this has not been studied while controlling for anal sphincter trauma. We aimed to investigate this association in women with intact anal sphincter presenting with pelvic floor dysfunction.

METHODS

This retrospective study analyzed 1133 women with intact anal sphincter presenting to a tertiary urogynecological center for pelvic floor dysfunction between 2014 and 2016. All women underwent a standardized interview, including assessment of symptoms of AI, clinical examination and three-/four-dimensional transperineal ultrasound. Descent of the rectal ampulla, true rectocele, enterocele, intussusception and anal sphincter trauma were diagnosed offline.

RESULTS

Mean age was 54.1 (range, 17.6-89.7) years and mean body mass index was 29.4 (range, 14.7-67.8) kg/m2 . AI was reported by 149 (13%) patients, with a median St Mark's anal incontinence score of 12 (interquartile range, 1-23). Significant posterior compartment prolapse was seen in 693 (61%) women on clinical examination. Overall, 638 (56%) women had posterior compartment prolapse on imaging: 527 (47%) had a true rectocele, 89 (7.9%) had an enterocele and 26 (2.3%) had an intussusception. Women with ultrasound-diagnosed enterocele had a significantly higher rate of AI (23.6% vs 12.3%; odds ratio (OR), 2.21 (95% CI, 1.31-3.72); P = 0.002), but when adjusted for potential confounders, this association was no longer significant (OR, 1.56 (95% CI, 0.82-2.77); P = 0.134).

CONCLUSION

In women without anal sphincter trauma, posterior compartment prolapse, whether diagnosed clinically or by imaging, was not shown to be associated with AI. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Diagnosis of maternal birth trauma by pelvic floor ultrasound

BRIEF SUMMARY

Maternal somatic birth trauma due to vaginal delivery is more common than generally assumed and an important cause of future morbidity. Maternal birth trauma may involve both psychological and somatic morbidity, some of it long-term and permanent. Somatic birth trauma is now understood to encompass not just episiotomy, perineal tears and obstetric anal sphincter injuries (OASI), but also trauma to the levator ani muscle, termed 'avulsion'. This review will focus on recent developments in the imaging diagnosis of maternal birth trauma, discuss the most important risk factors and strategies for primary and secondary prevention. Translabial and exo-anal ultrasound allow the assessment of maternal birth trauma in routine clinical practice and enable the use of levator avulsion and anal sphincter trauma as key performance indicators of maternity services. This is likely to lead to a greater awareness of maternal birth trauma amongst maternity caregivers and improved outcomes for patients, not the least due to an increasing emphasis on patient autonomy and informed consent in antenatal and intrapartum care.

Obstetric risk factors for anal sphincter trauma in a urogynecological population

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter tears are the single major modifiable risk factor for anal incontinence (AI) in women. We undertook a retrospective observational study in a tertiary urogynecology unit to describe the prevalence of sonographic anal sphincter defects in a urogynecological population and investigate obstetric risk factors.

METHODS

Files of women seen for investigation of pelvic floor disorders between January 2014 and May 2021 were reviewed. Sonographic defects of the external anal sphincter were analyzed using stored 4D ultrasound imaging data. Explanatory parameters were number of vaginal births, delivery mode, age at first vaginal birth, and birthweight of the first vaginally born baby.

RESULTS

Of 3,037 women seen during the inclusion period, data were missing in 219, leaving 2,818. AI was reported by 508 (18%), with a mean St Marks score of 11 (1-23) and a mean bother score of 5.9 (0-10). External sphincter defects were detected in 945 women (34%), with a "residual defect" in 343 (12%). The strongest risk factors for a residual defect were first vaginal birth and forceps, with higher-order multiparity adding risk. On multivariate analysis, forceps and vaginal parity >5 remained significant predictors, as opposed to age at first birth and birthweight of the firstborn.

CONCLUSIONS

In this observational study in urogynecological patients, 12% showed a residual EAS defect on imaging. The most obvious risk factors for the diagnosis of a residual defect on exo-anal imaging were the first vaginal birth and forceps, with higher-order vaginal parity conveying additional risk.

Use of endoanal ultrasound in detecting obstetric anal sphincter injury immediately after birth

INTRODUCTION

Obstetric anal sphincter injury (OASI) complicates around 5% of deliveries in primiparas. The study objective was to assess the utility of three-dimensional endoanal ultrasonography (3D-EAUS) in the diagnosis of OASI.

MATERIAL AND METHODS

The present study was designed to mirror screening settings with an unselected cohort of nulliparous women. All enrolled patients underwent clinical examination of the perineum by the caregiver, and 3D-EAUS was conducted. Post-processing of ultrasonography volume data was performed by an experienced colorectal surgeon who was blinded to all other data. The sensitivity, specificity, negative predictive value, and positive predictive value of 3D-EAUS in the diagnosis of OASI was evaluated. The trial is registered at ISCRTN: 18006769.

RESULTS

A total of 680 scans were performed, of which 18.5% were judged as "non-assessable", resulting in 554 assessable recordings. Sphincter defects were observed in 12.8% of all assessable recordings on 3D-EAUS (n = 71). With clinical examination set as the reference standard, ultrasound sensitivity in the diagnosis of OASI was 30.4%, whereas its specificity was 87.9%. The negative predictive value was 96.7% and the positive predictive value was only 9.9%. Comments were left on 175 examinations, of which 74% referred to the management of the examination.

CONCLUSIONS

Using 3D-EAUS in a maternity ward is demanding because staff generally have little experience in endoanal ultrasound, which contributes to difficulties in obtaining good image quality. When 3D-EAUS is performed to mirror screening settings, it adds no convincing diagnostic power to clinical examination in the diagnosis of OASI.

Validation of new ultrasound algorithm for estimating prevalence of anal sphincter trauma in a urogynecological population

OBJECTIVES

To estimate the prevalence of major perineal trauma in a urogynecological population, to test the predictive value of sonographic tear grading (Gillor algorithm) for anal incontinence (AI), AI bother score and St Mark's score, and to compare the predictive power of the Gillor algorithm with that of the residual-defect method.

METHODS

This was a retrospective study of 721 women attending a tertiary urogynecology unit between February 2019 and May 2021. All women underwent a standardized interview, including determination of St Mark's score and visual analog scale (VAS) bother score for AI, as well as exoanal (translabial) ultrasound with later offline analysis. Results were reported as the presence of a residual defect of the external anal sphincter (EAS), i.e. a discontinuity of ≥ 30° in ≥ 4/6 tomographic slices, and according to the Gillor algorithm (normal, Grade 3a, Grade 3b or Grade 3c/4).

RESULTS

Mean age at assessment was 57 (range, 19-93) years and mean body mass index was 30 (range, 17-57) kg/m² . Six hundred and thirty-six (88.2%) women were vaginally parous and 161 (22.3%) had undergone at least one forceps delivery. AI was reported by 186/721 (25.8%) women, with a median St Mark's score of 10 (interquartile range (IQR), 6-14) and a median VAS score of 6.3 (IQR, 3.9-10). EAS defects were detected in 261 (36.2%) women, with a residual defect diagnosed in 88 (12.2%). On sonographic grading according to the Gillor algorithm, we identified 532 (73.8%) women with a normal sphincter, 66 (9.2%) with Grade-3a tear, 87 (12.1%) with Grade-3b tear and 36 (5.0%) with Grade-3c/4 tear. In total, the Gillor algorithm classified 189 (26.2%) women as having suffered a major perineal tear. The two grading systems were in moderate agreement (κ, 0.537 (95% CI, 0.49-0.56); P < 0.001). There were weak, albeit significant, associations between EAS defects and measures of AI (P = 0.009 to P = 0.047), both for residual defect as well as the Gillor algorithm.

CONCLUSION

Neither the Gillor algorithm nor the residual-defect method of quantifying sphincter trauma on imaging is clearly superior in terms of predicting AI. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Location of obstetric anal sphincter injury scars on translabial tomographic ultrasound

OBJECTIVE

Obstetric anal sphincter injury (OASI) is a common preventable cause of anal incontinence. Both diagnosis and primary repair of OASI are often suboptimal, partly owing to the absence of effective clinical audit. The aim of this study was to evaluate the location of scars or defects of the external anal sphincter (EAS), diagnosed by translabial ultrasound (TLUS), following primary OASI repair.

METHODS

This was a retrospective analysis of 309 women who were seen at a tertiary obstetric unit after primary repair of OASI between June 2012 and May 2019. All women underwent a standardized interview, including St Mark's incontinence score, followed by clinical examination and TLUS assessment within 2-9 months after OASI repair. Postprocessing of TLUS volume datasets was performed by an investigator who was blinded to all other information. Tomographic ultrasound imaging was used to evaluate the presence of a scar or defect in the proximal and distal parts of the EAS. Women were classified into four groups according to the imaging findings: (1) no visible defect or distortion (likely false positive); (2) only proximal OASI; (3) only distal OASI; and (4) both proximal and distal OASI.

RESULTS

Of the 309 women seen during the study period, 34 were excluded because they were referred for reasons other than recent (< 1 year) OASI, 16 owing to missing data and four owing to poor image quality, leaving 255 patients for analysis. Women were seen on average 0.25 ± 0.1 years after the index birth, and their mean age at delivery was 29.1 ± 4.6 years. Anal incontinence was reported by 97 (38.0%) women. A scar or defect was seen only in the proximal part of the EAS in 64 (25.1%) women and only in the distal part in 19 (7.5%) (P < 0.001). In 165 (64.7%) women, the damage affected both the proximal and distal EAS.

CONCLUSIONS

EAS scars after primary OASI repair commonly affect the entire length of the EAS; however, partial tears seem to be more likely to occur proximally. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Postpartum ultrasound for the diagnosis of obstetrical anal sphincter injury

This review presents the available data on the diagnosis of obstetrical anal sphincter injury by postnatal ultrasound imaging. There is increasing evidence that anal sphincter tears are often missed after childbirth and, even when diagnosed, often suboptimally repaired, with a high rate of residual defects after reconstruction. Even after postpartum diagnosis and primary repair, 25% to 50% of patients will have persistent anal incontinence. As clinical diagnosis may fail in the detection and classification of obstetrical anal sphincter injury, the use of imaging has been proposed to improve the detection and treatment of these lacerations. Notably, 3-dimensional endoanal ultrasound is considered the gold standard in the detection of obstetrical anal sphincter injury, and recently, 4-dimensional transperineal ultrasound, commonly available in obstetrical and gynecologic settings, has proven to be effective as well. Avoidance of forceps delivery when possible, performance of a rectal examination after vaginal delivery and before repair of any severe perineal tear, and offering sonographic follow-up at 10 to 12 weeks after vaginal delivery in high-risk women (maternal age of ≥35 years, vaginal birth after cesarean delivery, forceps, prolonged second stage of labor, overt obstetrical anal sphincter injury, shoulder dystocia, and macrosomia) may help reduce morbidity arising from anal sphincter tears.

Ultrasound imaging of maternal birth trauma

INTRODUCTION AND HYPOTHESIS

The term 'maternal birth trauma' has undergone substantial changes in meaning over the last 2 decades. Leaving aside psychological morbidity, somatic trauma is now understood to encompass not just episiotomy, perineal tears and obstetric anal sphincter injuries (OASI), but also trauma to the levator ani muscle. This review covers diagnosis of maternal birth trauma by translabial ultrasound imaging.

METHODS

Narrative review.

RESULTS

Tomographic imaging of pelvic structures with the help of 4D ultrasound, used since 2007, has allowed international standardization and seems to be highly reproducible and valid for the diagnosis of OASI and levator avulsion.

CONCLUSIONS

Translabial and exo-anal ultrasound allows the assessment of maternal birth trauma in routine clinical practice and the utilization of avulsion and sphincter trauma as key performance indicators of maternity services. It is hoped that this will lead to a greater awareness of maternal birth trauma among maternity caregivers and improved outcomes for patients, both in the short term and in the decades to come.

Obstetric anal sphincter injuries: strategies for prevention, diagnosis, and management

Obstetric anal sphincter injuries (OASIS) are one of the most common causes of anal incontinence (AI) in women of reproductive age and can have a significant impact on quality of life. However, many women do not report symptoms to their physicians because of embarrassment and shame. Therefore, prevention and diagnosis of the tear is essential. Diagnostic strategies have evolved considerably in recent years, with an increase in prevalence of OASIS as a consequence. The use of 3D endoanal (3D-EAUS) and 4D transperineal ultrasound (4D-TPUS), in addition to standard clinical examination have enhanced the detection of OASIS. Once identified, adequate repair by a skilled practitioner and optimal postpartum management should be ensured in order to reduce the risk of anal incontinence. This review presents the available evidence on strategies for prevention, diagnosis, and management of OASIS.

The impact of a nationwide hands-on workshop on the diagnostic rates and management of obstetrical anal sphincter Injuries in Israel

AIM

The aim was to evaluate the influence of a half day, hands-on, workshop on the detection and repair of obstetric anal sphincter injuries (OASIs).

METHOD

Starting in February 2011, hands-on workshops for the diagnosis and repair of OASIs were delivered by trained urogynaecologists in departments of tertiary medical centres in Israel. The structure of the hands-on workshop resembles the workshop organized at the International Urogynecological Association annual conferences. Participants included medical staff, midwives and surgical residents from each medical centre. We collected data regarding the rate of OASIs, 1 year before and 1 year following the workshop, in 11 medical centres. The study population was composed of parturients with the following inclusion criteria: singleton pregnancy, vertex presentation and vaginal delivery. Pre-viable preterm gestations (< 24 weeks), birth weight < 500 g, stillborn, and those with major congenital anomalies, multifoetal pregnancies, breech presentations and caesarean deliveries were excluded from the analysis.

RESULTS

In the reviewed centres, 70 663 (49.3%) women delivered prior to the workshop (pre-workshop group) and 72 616 (50.7%) women delivered following the workshop (post-workshop group). Third- or fourth-degree perineal tears occurred in 248 women (0.35%) before the workshop, and in 328 (0.45%) following the workshop, a significant increase of 28.7% (P = 0.002). The increase in diagnosis was significant also in women with third-degree tears alone, 226 women (0.32%) before the workshop and 298 (0.41%) following the workshop, an increase of 28.3% (P = 0.005).

CONCLUSION

The detection rate of OASIs has significantly increased following the hands-on workshop. The implementation of such programmes is crucial for increasing awareness and detection rates of OASI following vaginal deliveries.