Exoanal ultrasound of the anal sphincter: normal anatomy and sphincter defects

Three-Dimensional Transperineal Ultrasound Assessment of the Anal Sphincter Immediately After Vaginal Birth: An Exploratory Study

OBJECTIVES

To assess the feasibility of acquiring adequate transperineal ultrasound (TPUS) volumes of the anal sphincter (AS) immediately after vaginal birth, the reproducibility of its measurements, and detecting defects therein.

METHODS

Secondary analysis of TPUS volumes of the AS, acquired immediately after vaginal birth with a transversely oriented convex probe. Two independent experts ranked off-line image quality as "inadequate," "adequate," or "ideal" using the Point-of-Care Ultrasound Image Quality scale. On "adequate" and "ideal" quality volumes, the length of the external AS at 6 and 12 o'clock, and the volume of the external and internal AS were measured. Additionally, volumes were screened for AS defects on tomographic ultrasound imaging. Subsequently, we rated the intra- and interrater agreement on those findings.

RESULTS

Of 183 volumes, 162 were considered "adequate" or of "ideal" quality (88.5%). Reasons for "inadequacy" were shadow artifacts (16/21), poor resolution (3/21), incomplete acquisition (1/21), or aberrant AS morphology (1/21). The intrarater reliability of two-dimensional (2D) and three-dimensional (3D) measurements was excellent, whereas interrater reliability was fair to good for 2D measurements and good for 3D measurements. In those tomographic ultrasound imaging (TUI) sequences including AS defects, the intra- and interrater reliability of the defect measurement were excellent [intraclass correlation coefficient (ICC) = 0.92 (0.80-0.94)] and moderate [ICC = 0.72 (0.63-0.79)]. In this cohort, there were only few (4/48; 8.3%) AS defects. However, grading them was poorly reproducible between experts.

CONCLUSION

TPUS of the AS immediately after vaginal birth yields adequate image quality and allows for reproducible measurements. In the few patients with AS defects, there was good agreement on the presence, but it was poor for the extent of defects.

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.

Morphological differences in the female anal sphincter complex between endoanal and exoanal ultrasound

INTRODUCTION AND HYPOTHESIS

This study was aimed at describing the morphological characteristics of the normal female anal sphincter complex (ASC) by high-resolution transperineal ultrasound (TPUS) and endoanal ultrasound (EAUS).

METHODS

Thirty volunteers, including 19 nulliparous and 11 women who had only given birth by Cesarean section, were recruited. The ASC was shown in a set of five slices by EAUS and 8 slices by TPUS. EAUS slices 1 and 5 matched TPUS slices 1 and 8; EAUS slices 2, 3, and 4 were approximately at the levels of TPUS slices 3, 5, and 7. The anterior and lateral EAS and IAS thicknesses were measured and the two methods were compared.

RESULTS

The median age was 29 years. The mean body mass index (BMI) was 20.6 kg/m². All measured values obtained by TPUS were normally distributed. The EAS thickness on EAUS slice 2 and the IAS thickness on EAUS slices 2 and 3 were not normally distributed. The mean anterior EAS thickness was 2.51 mm, 2.96 mm, and 3.53 mm in slices 3, 5, and 7 on TPUS and was significantly thinner than that in slices 2 (2.62 mm), 3 (3.77 mm), and 4 (4.62 mm) on EAUS. In contrast, the IAS was markedly thicker on TPUS. The ratio of sphincter thickness anteriorly to laterally was similar using the two methods.

CONCLUSIONS

The morphological characteristics of EAS shown by TPUS and EAUS were similar. EAS was thinner, and IAS was thicker on TPUS. The IAS seems to be distorted on endoanal imaging.

Obstetric anal sphincter injuries (OASIS): using transperineal ultrasound (TPUS) for detecting, visualizing and monitoring the healing process

Purpose

The aim of this study was to examine whether OASIS, and its extent, can be confirmed or excluded using transperineal ultrasound (TPUS). A further objective of this study was to monitor the healing process over a period of 6 months and to establish a connection between the sonographic appearance of obstetric anal sphincter injury (OASIS) and anal incontinence.

Materials and methods

In this retrospective clinical study, women with OASIS who gave birth between March 2014 and August 2019 were enrolled. All the patients underwent TPUS 3 days and 6 months after delivery. A GE E8 Voluson ultrasound system with a 3.5–5 MHz ultrasound probe was used. The ultrasound images showed a third-degree injury, with the measurement of the width of the tear and its extent (superficial, partial, complete, EAS and IAS involvement). A positive contraction effect, a sign of sufficient contraction, was documented. Six months after delivery, a sonographic assessment of the healing (healed, scar or still fully present) was performed. A Wexner score was obtained from each patient. The patients’ medical histories, including age, parity, episiotomy and child’s weight, were added.

Results

Thirty-one of the 55 recruited patients were included in the statistical evaluation. Three patients were excluded from the statistical evaluation because OASIS was excluded on TPUS 3 days after delivery. One patient underwent revision surgery for anal incontinence and an inadequately repaired anal sphincter injury, as shown sonographic assessment, 9 days after delivery. Twenty patients were excluded for other reasons. The results suggest that a tear that appears smaller (in mm) after 3 days implies better healing after 6 months. This effect was statistically significant, with a significance level of alpha = 5% (p = 0.0328). Regarding anal incontinence, women who received an episiotomy had fewer anal incontinence symptoms after 6 months. The effect of episiotomy was statistically significant, with a significance level of alpha = 5% (p = 0.0367).

Conclusion

TPUS is an accessible, non-invasive method for detecting, quantifying, following-up and monitoring OASIS in patients with third-degree perineal tears. The width, as obtained by sonography, is important with regard to the healing of OASIS. A mediolateral episiotomy seems to prevent anal incontinence after 6 months.

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.

Transperineal anal sphincter complex evaluation after obstetric anal sphincter injuries: With or without tomographic ultrasound imaging technique?

OBJECTIVES

"Significant" obstetric anal sphincter injuries (OASIS) have been defined as visible defects of at least 30° in at least 4/6 slices using tomographic ultrasound imaging (TUI) with transperineal ultrasound (TPUS). The objective of this study was to assess if TUI is mandatory for the evaluation of OASIS.

METHODS

Patients with a history of OASIS were evaluated by performing 3D-endoanal ultrasound (EAUS) and 3D-TPUS with and without TUI. Any damage to the internal (IAS) or external (EAS) anal sphincters was recorded and scored using the Starck's and the Norderval's systems. Intraobserver and inter-techniques correlations were calculated.

RESULTS

From September 2012 to May 2015, 63 women, mean age 32.5 ± 4.6 years, with OASIS (3a: 26 pts., 41.3 %; 3b: 26 pts., 41.3 %; 3c: 6 pts., 9.5 %, 4: 4 pts., 6.3 %, "button hole" tear: 1 pt., 1.6 %). Inter-technique and intraobserver correlations were excellent (TUI: k = 0.9; sweeping technique: k = 0.85; EAUS: k = 0.9) in determining OASIS. Using the Starck's Score, excellent correlation was found for both TPUS modalities (TUI: k = 0.86; sweeping technique: k = 0.89). However, for the different individual parameters, the correlation was moderate for EAS depth (TUI: k = 0.44; sweeping technique: k = 0.5) and good for IAS depth (TUI: k = 0.7; sweeping technique: k = 0.78). Similar results were found using the Norderval's classification.

CONCLUSIONS

OASIS can be assessed by TPUS without TUI technique, dragging the rendered box and following the anal canal from the anal verge to the anorectal junction in the longitudinal plane and describing findings.

Does exclusion of subcutaneous external anal sphincter on exoanal imaging matter?

OBJECTIVE

There is some speculation that an intact distal anal sphincter complex is of decisive importance for continence, although the external anal sphincter (EAS) is considered to be a single functional and anatomical entity. On tomographic translabial ultrasound (TLUS), the caudal slice at the level of the subcutaneous EAS is currently omitted from the diagnostic algorithm due to the prevalence of artifact at that level. The aim of this study was to determine the predictive value of assessment of the subcutaneous EAS on tomographic TLUS for anal incontinence (AI).

METHODS

This was a retrospective study of 463 women seen at our urogynecological service in 2015. All underwent a standardized questionnaire, including determination of St Mark's incontinence score (SMIS), clinical examination and three-/four-dimensional TLUS. On tomographic TLUS, EAS defect angles in slices one to seven were measured on maximum pelvic floor muscle contraction. A slice was defined as positive for a defect if the defect angle was ≥ 30°. The association between significant subcutaneous EAS trauma (i.e. defect angle of ≥ 30° in slice seven) and symptoms of AI, symptom bother score and SMIS was assessed. The performances of the standard six-slice model and the seven-slice model, including the subcutaneous EAS, in the prediction of AI were compared.

RESULTS

While there was a highly significant association between all measures of AI and significant EAS trauma in slice seven, addition of the seventh slice to the existing six-slice model did not improve the predictive value for AI.

CONCLUSION

As inclusion of the subcutaneous slice of the EAS on tomographic TLUS does not seem to improve the predictive value for AI, the current methodology for assessment of EAS trauma on tomographic TLUS can remain unchanged. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

What is a significant defect of the anal sphincter on translabial ultrasound?

OBJECTIVE

The anal sphincter is commonly evaluated with endoanal ultrasound. Recently, translabial ultrasound imaging has been proposed for sphincter imaging, with moderate to good correlation between the methods. An endosonographic defect is defined as one with a radial extension of > 30° in at least two-thirds of the length of the anal sphincter. This is equivalent to defining significant anal sphincter trauma on translabial tomographic ultrasound imaging (TUI) as a defect in at least four of six slices, a definition which has been validated. This study was designed to validate a residual defect angle of > 30° for the definition of significant anal sphincter trauma on translabial ultrasound.

METHODS

This was a retrospective study involving 399 women attending a tertiary urogynecology unit in 2014. All underwent a standardized interview, including determination of St Mark's fecal incontinence score (SMIS), clinical examination and 3D/4D translabial ultrasound examination with the woman at rest and on pelvic floor muscle contraction (PFMC). External (EAS) and internal (IAS) anal sphincter defect angles were measured in individual TUI slices and associations with anal incontinence symptoms, bother score and SMIS were analyzed.

RESULTS

There were weak but significant correlations of anal incontinence symptoms, bother score and SMIS with EAS and IAS defect angle, measured on images acquired with the woman at rest and on PFMC. The predictive value of single-slice defect angle on TUI was low, and areas under the receiver-operating-characteristics curves were too low to determine a distinct cut-off value for defect angle.

CONCLUSIONS

Anal sphincter residual defects on single translabial TUI slices are weakly associated with measures of anal incontinence. Single-slice defect angle is too poor a predictor to allow validation of the 30° defect angle cut-off used in endoanal ultrasound. Larger studies in populations with a higher prevalence of anal incontinence are needed before we can disregard anal sphincter defects smaller than 30° on translabial ultrasound. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Anal sphincter imaging: better done at rest or on pelvic floor muscle contraction?

INTRODUCTION AND HYPOTHESIS

Exo-anal ultrasound imaging of the anal sphincter is usually undertaken on pelvic floor muscle contraction (PFMC) as this seems to enhance tissue discrimination. Some women are unable to achieve a satisfactory PFMC, and in this situation, the sphincter is assessed at rest. We aimed to determine whether sphincter imaging at rest is inferior to imaging on PFMC.

METHODS

We analysed 441 women in this retrospective study. All underwent a standardised interview, including St Mark's incontinence score, clinical examination and 4D trans-labial ultrasound (TLUS). On analysing volume data, tomographic imaging was used to obtain a standardised set of slices at rest and on PFMC to evaluate external anal sphincter (EAS) and internal anal sphincter (IAS) trauma as described previously.

RESULTS

When assessments obtained from volumes acquired at rest and on PFMC were tested against measures of anal incontinence (AI), all associations between the diagnosis of significant anal sphincter defects and AI were no stronger when imaging was performed on PFMC. On cross-tabulation, the percentage agreement for significant defects of the EAS and IAS at rest and on PFMC was 96.5% and 98.9% respectively, if discrepancy by one slice was allowed.

CONCLUSIONS

Exo-anal tomographic imaging of sphincter defects at rest seems sufficiently valid for clinical use and may not be inferior to sphincter assessment on pelvic floor muscle contraction.

Exo-anal imaging of the anal sphincter: a comparison between introital and transperineal image acquisition

INTRODUCTION AND HYPOTHESIS

Three-dimensional exoanal ultrasound imaging of the anal sphincter may be obtained transperineally with a convex probe, or at the introitus with a transvaginal probe. We hypothesised that introital acquisition would yield better quality and more reproducible evaluation.

METHODS

We acquired three 3D volumes of the anal sphincter (one transperineal transverse with a 4- to 8-MHz convex probe and two introital with a 5- to 9-MHz probe in transverse and mid-sagittal view) in 20 representative women attending the gynaecology clinic. Each 3D dataset was anonymised and hence blinded for clinical data and for acquisition method. Images were analysed off-line by two expert specifically trained ultrasonographers in a random order to assess image quality, sphincter integrity and sphincteric measurements. We assessed the intra- and interrater agreement by the Cohen's kappa (κ) and by the intraclass correlation coefficient for categorical and continuous variables respectively.

RESULTS

The mid-sagittal introital acquisition had most inconclusive images owing to unsatisfactory quality, on which raters agreed (К = 0.80). Subsequently, agreement in the anal sphincter evaluation between transverse introital and transperineal acquisitions was compared. Agreement on internal anal sphincter gap was excellent for both transverse introital (К = 0.87) and transperineal acquisition (К = 0.93). Agreement on external anal sphincter discontinuity was excellent for the transperineal acquisition (К = 0.87) and good for the transverse introital acquisition (К = 0.73). Intra- and interrater agreement of external and internal anal sphincteric measurements were best for transperineal acquisitions.

CONCLUSIONS

In our hands, transperineal acquisition with a 4- to 8-MHz probe performed better than introital acquisition with a 5- to 9-MHz probe in the assessment of the anal sphincter complex.

How repeatable is assessment of external anal sphincter trauma by exoanal 4D ultrasound?

OBJECTIVE

Three-/four-dimensional translabial ultrasound (TLUS) is gaining popularity for the assessment of anal sphincter trauma, although repeatability data are lacking. This study aimed to determine the repeatability of tomographic ultrasound imaging (TUI) on TLUS for the diagnosis of external anal sphincter (EAS) trauma and compare the performance of a novice with that of an experienced investigator.

METHODS

This was a retrospective study of archived ultrasound datasets of patients who presented with symptoms of pelvic floor dysfunction and were examined twice between 2012 and 2016 at an average interval of 260 (range, 1-1100) days. All volumes were obtained using a GE Medical Systems Voluson 730 Expert or E8 ultrasound system. Post-processing of volumes was performed independently by two investigators, one with over 1 year's experience and another with no prior experience in using TUI, who were blinded to clinical data, each other's results and the results obtained at the first timepoint. Significant trauma on EAS was diagnosed if four of the six TUI slices showed a defect of ≥ 30°. Intra- and interobserver agreement were determined using Cohen's kappa (κ) and intraclass correlation coefficients.

RESULTS

During the study period, 105 women underwent two TLUS assessments of the anal sphincter. Of these, 103 patients with ultrasound volumes available for both timepoints were included in the analysis. The novice investigator demonstrated average repeatability for assessment of significant EAS trauma and single-slice defect (κ, 0.30 and 0.22, respectively) despite relatively high agreement between measurements obtained at the two timepoints (84.5% and 79.3%, respectively). The experienced investigator demonstrated good to very good repeatability for significant EAS trauma and single-slice defect (κ, 0.91 and 0.78, respectively) between the two assessments, which equates to 98.1% and 94.7% agreement, respectively.

CONCLUSION

The repeatability of TLUS measurements for diagnosis of EAS trauma seems to be very good when imaging is undertaken with state-of-the-art equipment and the analysis is performed by an experienced observer; however, the performance of a novice investigator is much poorer. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

How Valid Is Tomographic Ultrasound Imaging in Diagnosing Levator and Anal Sphincter Trauma?

OBJECTIVES

Three-/four-dimensional translabial ultrasound (US) is increasingly used to image the levator ani and anal sphincters, especially in the form of tomographic US. The aim of the study was to evaluate the validity of these published methods.

METHODS

This work was a retrospective analysis of datasets of 172 nulliparous women who attended 2 tertiary urogynecologic centers for symptoms of pelvic floor dysfunction between June 2012 and September 2016. All patients had a standardized interview, clinical examination, and 4-dimensional translabial US examination. An evaluation of volume data was performed by the first author, who was blinded against all clinical data, including parity. An assessment for levator avulsion and anal sphincter defects was performed using stored US volume data.

RESULTS

Data sets of 162 and 153 nulliparous women were available for levator and anal sphincter assessments, respectively. On the assessment by the first author, a complete avulsion was diagnosed in 3 nulliparas. On a review by 2 senior authors, 1 was judged as positive and the other 2 as normal. On the sphincter assessment, 2 significant external anal sphincter defects were detected. On the review, 1 was judged as false-positive. The second was judged as highly abnormal by all authors. Therefore, 1 nullipara each was diagnosed with avulsion and a significant external anal sphincter defect.

CONCLUSIONS

Published diagnostic criteria for levator avulsion and external anal sphincter trauma on tomographic US imaging are highly unlikely to result in false-positive findings. This finding supports the clinical validity of this method.

Medium- to Long-term Follow-up of Obstetric Anal Sphincter Injury

BACKGROUND

Obstetric anal sphincter injury is the primary modifiable risk factor for anal incontinence in women. Currently, endoanal ultrasound is most commonly used to detect residual anal sphincter defects after childbirth. Translabial ultrasound has recently been introduced as a noninvasive alternative.

OBJECTIVES

This study aimed to determine medium- to long-term outcomes in women after obstetric anal sphincter injuries diagnosed and repaired at delivery.

DESIGN

This is a cross-sectional study.

SETTINGS

This study was performed in a tertiary obstetric unit.

PATIENTS

Between 2005 and 2015, 707 women were diagnosed with obstetric anal sphincter injuries; 146 followed an invitation for follow-up.

INTERVENTIONS

Clinical examination, anal manometry, and translabial ultrasound were performed.

MAIN OUTCOME MEASURES

The primary outcomes measured were the St Mark incontinence score and the evidence of sphincter disruption on translabial ultrasound.

RESULTS

Of 372 contactable patients, 146 attended at a mean follow-up of 6.6 years (1.7-11.9), of which 75 (51%) reported symptoms of anal incontinence with a median "bother score" of 6 (interquartile range, 3-8). Median St Mark score was 3 (interquartile range, 2-5). Twenty-four (16%) had a score of ≥5. Women who had been diagnosed with a 3c/4th degree tear had more symptoms (58% vs 44%), significantly lower mean maximal resting pressure (p < 0.001), maximal squeeze pressure (p < 0.001), and more residual external (p < 0.001) and internal (p = 0.012) sphincter defects in comparison with those who had a 3a/3b tear. Women with residual external sphincter defects had lower mean maximal squeeze pressure (p = 0.02). Residual internal sphincter defects (p = 0.001) and levator avulsion (p = 0.048) are independent risk factors for anal incontinence on multivariate modeling.

LIMITATIONS

This study was limited by the lack of predelivery data of bowel symptoms and BMI and incomplete intrapartum documentation of tear grade.

CONCLUSIONS

Symptoms of anal incontinence were highly prevalent (51%), with a high bother score of 6. St Mark scores were associated with residual internal anal sphincter defects and levator avulsion. Women who had a higher tear grade showed a higher incidence of residual sphincter defects and lower manometry pressures. See Video Abstract at http://links.lww.com/DCR/A824.

Translabial US and Dynamic MR Imaging of the Pelvic Floor: Normal Anatomy and Dysfunction

Pelvic floor dysfunction (PFD) is a common condition that typically affects women older than 50 years and decreases the quality of life. Weakening of support structures can involve all three pelvic compartments and cause a combination of symptoms, including constipation, urinary and fecal incontinence, obstructed defecation, pelvic pain, perineal bulging, and sexual dysfunction. The causes of PFD are complex and multifactorial; however, vaginal delivery is considered a major predisposing factor. Physical examination alone is limited in the evaluation of PFD; it frequently leads to an underestimation of the involved compartments. Imaging has an important role in the clinical evaluation, yielding invaluable information for patient counseling and surgical planning. Three- and four-dimensional translabial ultrasonography (US) is a relatively new imaging modality with high accuracy in the evaluation of PFD such as urinary incontinence, pelvic organ prolapse, and puborectalis avulsion. Evaluation of mesh implants is another important indication for this modality. Dynamic magnetic resonance (MR) imaging of the pelvic floor is a well-established modality for pelvic floor evaluation, with high-resolution images yielding detailed anatomic information and dynamic sequences yielding functional data. Specific protocols and dedicated image interpretation are required with both of these imaging methods. In this article, the authors review the normal anatomy of the female pelvic floor by using a practical approach, discuss the roles of translabial US and MR imaging in the investigation of PFD, describe the most appropriate imaging protocols, and illustrate the most common imaging findings of PFD in the anterior, middle, and posterior compartments of the pelvis. Online supplemental material is available for this article. ^©RSNA, 2018.

Anal sphincter defects and fecal incontinence 15-24 years after first delivery: a cross-sectional study

OBJECTIVES

To establish the prevalence of external (EAS) and internal (IAS) anal sphincter defects present 15-24 years after childbirth according to mode of delivery, and their association with development of fecal incontinence (FI). The study additionally aimed to compare the proportion of women with obstetric anal sphincter injuries (OASIS) reported at delivery with the proportion of women with sphincter defect detected on ultrasound 15-24 years later.

METHODS

This was a cross-sectional study including 563 women who delivered their first child between 1990 and 1997. Women responded to a validated questionnaire (Pelvic Floor Distress Inventory) in 2013-2014, from which the proportion of women with FI was recorded. Information about OASIS was obtained from the National Birth Registry. Study participants underwent four-dimensional transperineal ultrasound examination. Defect of EAS or IAS of ≥ 30° in at least four of six slices on tomographic ultrasound was considered a significant defect and was recorded. Four study groups were defined based on mode of delivery of the first child. Women who had delivered only by Cesarean section (CS) constituted the CS group. Women in the normal vaginal delivery (NVD) group had NVD of their first child and subsequent deliveries could be NVD or CS. The forceps delivery (FD) group included women who had FD, NVD or CS after FD of their first born. The vacuum delivery (VD) group included women who had VD, NVD or CS after VD of their first born. Multiple logistic regression was used to calculate adjusted odds ratios (aORs) for comparison of prevalence of an EAS defect following different modes of delivery and to test its association with FI. Fisher's exact test was used to calculate crude odds ratios (ORs) for IAS defects.

RESULTS

Defects of EAS and IAS were found after NVD (n = 201) in 10% and 1% of cases, respectively, after FD (n = 144) in 32% and 7% of cases and after VD (n = 120) in 15% and 4% of cases. No defects were found after CS (n = 98). FD was associated with increased risk of EAS defect compared with NVD (aOR = 3.6; 95% CI, 2.0-6.6) and VD (aOR = 3.0; 95% CI, 1.6-5.6) and with increased risk of IAS defect compared with NVD (OR = 7.4; 95% CI, 1.5-70.5). The difference between VD and NVD was not significant for EAS or IAS. FI was reported in 18% of women with an EAS defect, in 29% with an IAS defect and in 8% without a sphincter defect. EAS and IAS defects were associated with increased risk of FI (aOR = 2.5 (95% CI, 1.3-4.9) and OR = 4.2 (95% CI, 1.1-13.5), respectively). Of the ultrasonographic sphincter defects, 80% were not reported as OASIS at first or subsequent deliveries.

CONCLUSIONS

Anal sphincter defects visualized on transperineal ultrasound 15-24 years after first delivery were associated with FD and development of FI. Ultrasound revealed a high proportion of sphincter defects that were not recorded as OASIS at delivery. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Exoanal Imaging of the Anal Sphincters

Since its introduction in the early 1990s, endoanal sonography has become the mainstay of morphologic assessment of the anal canal and sphincter, especially for obstetric anal sphincter trauma. Lack of availability of suitable systems and the invasive nature of the method have limited uptake and clinical utility. More recently, exoanal or transperineal/translabial tomographic imaging has been developed as a noninvasive alternative. This pictorial overview aims to introduce the reader to this new diagnostic modality and to demonstrate common findings in asymptomatic and symptomatic women.

Postpartum two- and three-dimensional ultrasound evaluation of anal sphincter complex in women with obstetric anal sphincter injury

OBJECTIVE

To compare the sensitivity and specificity of two- (2D) and three- (3D) dimensional transperineal ultrasound (TPUS) and 3D endovaginal ultrasound (EVUS) with the gold standard 3D endoanal ultrasound (EAUS) in detecting residual defects after primary repair of obstetric anal sphincter injuries (OASIS).

METHODS

External (EAS) and internal (IAS) anal sphincters were evaluated by the four ultrasound modalities in women with repaired OASIS. 2D-TPUS was evaluated in real-time, whereas 3D-TPUS, 3D-EVUS and 3D-EAUS volumes were evaluated offline by six blinded readers. The presence/absence of any tear in EAS or IAS was recorded and defects were scored according to the Starck system. Sensitivity, specificity and predictive values were calculated, using 3D-EAUS as reference standard. Inter- and intraobserver analyses were performed for all 3D imaging modalities. Association between patients' symptoms (Wexner score) and ultrasound findings (Starck score) was calculated.

RESULTS

Images from 55 patients were analyzed. Compared with findings on 3D-EAUS, the agreement for EAS evaluation was poor for 3D-EVUS (κ = 0.01), fair for 2D-TPUS (κ = 0.30) and good for 3D-TPUS (κ = 0.73). The agreement for IAS evaluation was moderate for both 3D-EVUS (κ = 0.41) and 2D-TPUS (κ = 0.52) and good for 3D-TPUS (κ = 0.66). Good intraobserver (3D-EAUS, κ = 0.73; 3D-TPUS, κ = 0.78) and interobserver (3D-EAUS, κ = 0.68; 3D-TPUS, κ = 0.60) agreement was reported. Significant association between Starck and Wexner scores was found only for 3D-EAUS (Spearman's rho = 0.277, P = 0.04).

CONCLUSIONS

2D-TPUS and 3D-EVUS are not accurate modalities for the assessment of anal sphincters after repair of OASIS. 3D-TPUS shows good agreement with the gold standard 3D-EAUS and a high sensitivity in detecting residual defects. It, thus, has potential as a screening tool after primary repair of OASIS. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

[Applicability of 3/4D transperineal ultrasound for the diagnosis of anal sphincter injury during the immediate pospartum]

BACKGROUND

The most common cause of anal sphincter injuries in women is vaginal birth. Endo-anal ultrasound is currently used for the diagnosis of anal sphincter defect. However, due to the inconvenience caused, it is not an applicable technique during the immediate post-partum. The aim of this study was to determine whether transperineal ultrasound in 3/4D is a useful diagnostic method for the assessment of anal sphincter during the immediate post-partum.

MATERIAL AND METHODS

A prospective study was conducted on the vaginal deliveries performed between September 2012 and June 2013 in the Valme University Hospital (Seville). Obstetric and foetal parameters that could influence the onset of perineal tears were studied. The patients underwent a transperineal 3/4D ultrasound and a multislice study (48hours after birth).

RESULTS

The study included 146 puerperal women. The sphincter complex was assessed in all of them during the immediate post-partum. External anal injuries were observed in 10.3% of the cases. In 8.2% of cases, the primary suture of the external anal sphincter was detected during ultrasound examination, and 2.1% of asymptomatic lesions were diagnosed only with post-partum ultrasound. None of the patients reported discomfort or pain.

CONCLUSIONS

The 3-dimensional transperineal ultrasound is helpful in determining the primary repair of the anal sphincter during the immediate post-partum, with no discomfort for patients, as well as for establishing those early sphincter injuries that go unnoticed during vaginal delivery.

Anal sphincter trauma and anal incontinence in urogynecological patients

OBJECTIVES

To determine the prevalence of evidence of residual obstetric anal sphincter injury, to evaluate its association with anal incontinence (AI) and to establish minimal diagnostic criteria for significant (residual) external anal sphincter (EAS) trauma.

METHODS

This was a retrospective analysis of ultrasound volume datasets of 501 patients attending a tertiary urogynecological unit. All patients underwent a standardized interview including determination of St Mark's score for those presenting with AI. Tomographic ultrasound imaging (TUI) was used to evaluate the EAS and the internal anal sphincter (IAS).

RESULTS

Among a total of 501 women, significant EAS and IAS defects were found in 88 and 59, respectively, and AI was reported by 69 (14%). Optimal prediction of AI was achieved using a model that included four abnormal slices of the EAS on TUI. IAS defects were found to be less likely to be associated with AI. In a multivariable model controlling for age and IAS trauma, the presence of at least four abnormal slices gave an 18-fold (95% CI, 9-36; P < 0.0001) increase in the likelihood of AI, compared with those with fewer than four abnormal slices. Using receiver-operating characteristics curve statistics, this model yielded an area under the curve of 0.86 (95% CI, 0.80-0.92).

CONCLUSIONS

Both AI and significant EAS trauma are common in patients attending urogynecological units, and are strongly associated with each other. Abnormalities of the IAS seem to be less important in predicting AI. Our data support the practice of using, as a minimal criterion, defects present in four of the six slices on TUI for the diagnosis of significant EAS trauma.

Residual defects of the external anal sphincter following primary repair: an observational study using transperineal ultrasound

OBJECTIVES

Obstetric anal sphincter tears are common and an important factor in the etiology of anal incontinence. The objective of the study was to evaluate the prevalence of residual defects of the external anal sphincter (EAS) after primary repair of obstetric anal sphincter injury using four-dimensional (4D) transperineal ultrasound and to correlate sonographic findings of residual defects and levator avulsion with significant symptoms of anal incontinence, defined as St Mark's fecal incontinence score (SMIS) of ≥ 5.

METHODS

This was a retrospective observational study. One-hundred and forty women were seen after primary repair of obstetric anal sphincter tears in a dedicated perineal clinic at a tertiary hospital in Australia. They all underwent a standardized interview, and physical and 4D transperineal ultrasound examination.

RESULTS

Mean follow-up interval was 1.9 months after delivery. Eighty-nine (64%) women had a 3a/3b tear, 28 (20%) a 3c/4(th) degree tear and 23 (16%) an unclassified 3(rd) degree tear. Thirty-five (25%) patients reported symptoms of anal incontinence. Nine had an SMIS of ≥ 5. A residual defect was found in 56 (40%) cases and levator avulsion in 27 (19%). On multivariate logistic regression, residual defects (P = 0.03; odds ratio (OR) = 6.38; 95% CI, 1.23-33.0) and levator avulsion (P = 0.047; OR = 4.38; 95% CI, 1.02-18.77) were found to be independent risk factors for anal incontinence.

CONCLUSIONS

Residual defects of the EAS were found on transperineal ultrasound in 40% of women after primary repair of obstetric anal sphincter injuries. Although most were asymptomatic, residual anal sphincter defects and levator avulsion were associated with significant symptoms of anal incontinence as quantified using the SMIS.

Posterior pelvic floor disorders and obstructed defecation syndrome: clinical and therapeutic approach

There are no clear recommended imaging guidelines for the assessment of patients presenting primarily with obstructed defecation syndrome and defecation difficulty. The gold standard has always been the defecating proctogram which may require a rather poorly tolerated extended technique involving high-radiation exposure in young women which includes cystography, vaginography, small bowel opacification, and occasional peritoneography. The development of dynamic magnetic resonance imaging has obviated many of these extended techniques and may be supplemented by novel ultrasonographic methods including dynamic transperineal sonography, real-time 3D translabial ultrasound and 3D dynamic echodefecography. Patients potentially suitable for surgical treatment display a multiplicity of pelvic floor and perineal soft-tissue anomalies where one pathology (such as rectocele or enterocele) are considered dominant. Despite the introduction of recent stapled and robotic technologies, there is a dual dialog concerning the functional outcome of these procedures. Imaging and surgical algorithms for these patients are provided.

Ultrasound imaging of the anal sphincter complex: a review

Endoanal ultrasound is now regarded as the gold standard for evaluating anal sphincter pathology in the investigation of anal incontinence. The advent of three-dimensional ultrasound has further improved our understanding of the two-dimensional technique. Endoanal ultrasound requires specialised equipment and its relative invasiveness has prompted clinicians to explore alternative imaging techniques. Transvaginal and transperineal ultrasound have been recently evaluated as alternative imaging modalities. However, the need for technique standardisation, validation and reporting is of paramount importance. We conducted a MEDLINE search (1950 to February 2010) and critically reviewed studies using the three imaging techniques in evaluating anal sphincter integrity.

Ultrasound in the investigation of posterior compartment vaginal prolapse and obstructed defecation

Recent developments in diagnostic imaging have made gynecologists, colorectal surgeons and gastroenterologists realize as never before that they share a common interest in anorectal and pelvic floor dysfunction. While we often may be using different words to describe the same phenomenon (e.g. anismus/vaginismus) or attributing different meanings to the same words (e.g. rectocele), we look after patients with problems that transcend the borders of our respective specialties. Like no other diagnostic modality, imaging helps us understand each other and provides new insights into conditions we all need to learn to investigate better in order to improve clinical management. In this review we attempt to show what modern ultrasound imaging can contribute to the diagnostic work-up of patients with posterior vaginal wall prolapse, obstructed defecation and rectal intussusception/prolapse. In summary, it is evident that translabial/perineal ultrasound can serve as a first-line diagnostic tool in women with such complaints, replacing defecation proctography and MR proctography in a large proportion of female patients. This is advantageous for the women themselves because ultrasound is much better tolerated, as well as for healthcare systems since sonographic imaging is much less expensive. However, there is a substantial need for education, which currently remains unmet.

Three-dimensional transperineal ultrasound findings associated with anal incontinence after intrapartum sphincter tears in primiparous women

OBJECTIVE

Three-dimensional transperineal sonography (3D-TPS) performed in women following third- or fourth-degree intrapartum tears repaired with the overlapping technique demonstrates characteristic signs. The aim of this study was to investigate the correlation of these signs with clinical complaints of incontinence.

METHODS

This was a prospective observational study. Sixty primiparous women underwent 3D-TPS 3-42 (mean, 10.6) months after surgical repair of third- or fourth-degree postpartum sphincter tears with the overlapping technique and were evaluated for clinical degree of incontinence using the St Mark's Incontinence Score (SMIS) questionnaire. The following signs were assessed on 3D-TPS: interruption of the internal anal sphincter or external anal sphincter, 'half moon' sign, changes in the mucosal folds and thickening of the external anal sphincter in the area of sphincter repair. As a comparison group, 27 primiparous women after normal vaginal delivery, without clinically recognized anal sphincter tears, were evaluated similarly, 3-37 (mean, 9.9) months postpartum.

RESULTS

Abnormal sonographic signs were apparent in 35 (58.3%) of 60 women in the study group, and 39 (65%) of 60 had some clinical complaints of incontinence 3-42 months after delivery, most of a mild degree. Higher SMIS results were found in women of the study group than in those of the comparison group (mean (SD) 2.80 (0.481) vs. 1.15 (0.365); P = 0.018). The rates of incontinence were similar between the women in the study group with normal ultrasound findings and the women in the comparison group (9/25 vs. 10/27; relative risk (RR) = 0.97, 95% CI, 0.47-1.97).

CONCLUSIONS

Sonographic signs of anal sphincter tear and repair had disappeared at follow-up examination in almost half of the patients, and therefore this examination should be deferred from the early postpartum period. A substantial proportion of women report some complaint of incontinence after sphincter repair, most of a slight degree. Such complaints are associated with abnormal 3D-TPS findings at follow up, while in women with a normal 3D-TPS scan the rate of incontinence complaints is similar to that in women after normal delivery.

Female pelvic floor dysfunction--an imaging perspective

Female pelvic floor dysfunction encompasses a range of morbidities, including urinary incontinence, female pelvic organ prolapse, anal incontinence and obstructed defecation. Patients often present with symptoms covered by several specialties including gastroenterology, colorectal surgery, urology and gynecology. Imaging can therefore bring clinicians from multiple specialties together by revealing that we frequently deal with different aspects of one underlying problem or pathophysiological process. This article provides an interdisciplinary imaging perspective on the pelvic floor. Modern pelvic floor imaging comprises defecation proctography, translabial and endorectal ultrasound, and static and dynamic MRI. This Perspectives focuses on the potential use of translabial ultrasound, including 3D and 4D applications, for diagnosis of pelvic floor disorders. Over the next decade, pelvic floor imaging will most likely be integrated into mainstream diagnostics in obstetrics and gynecology and colorectal surgery. Using imaging to facilitate communication between different specialties has the potential to greatly improve the multidisciplinary management of complex pelvic floor disorders.

The diagnostic accuracy of endovaginal and transperineal ultrasound for detecting anal sphincter defects: The PREDICT study

AIM

To determine the accuracy and predictive value of transperineal (TPU) and endovaginal ultrasound (EVU) in the detection of anal sphincter defects in women with obstetric anal sphincter injuries and/or postpartum symptoms of faecal incontinence.

MATERIALS AND METHODS

One hundred and sixty-five women were recruited, four women were excluded as they were seen years after their last delivery. TPU and EVU, followed by endonanal ultrasound (EAU), were performed using the B&K Viking 2400 scanner. Sensitivity and specificity, as well as predictive values with 95% confidence intervals, for detecting anal sphincter defects were calculated for EVU and TPU, using EAU as the reference standard.

RESULTS

On EAU a defect was found in 42 (26%) women: 39 (93%) had an external (EAS) and 23 (55%) an internal anal sphincter (IAS) defect. Analysable images of one level of the EAS combined with an analysable IAS were available in 140 (87%) women for EVU and in 131 (81%) for TPU. The sensitivity and specificity for the detection of any defect was 48% (30-67%) and 85% (77-91%) for EVU and 64% (44-81%) and 85% (77-91%) for TPU, respectively.

CONCLUSION

Although EAU using a rotating endoprobe is the validated reference standard in the identification of anal sphincter defects, it is not universally available. However while TPU and/or EVU with conventional ultrasound probes can be useful in identifying normality, for clinical purposes they are not sensitive enough to identify an underlying sphincter defect.

Pelvic floor ultrasound: a review

Imaging currently plays a limited role in the investigation of pelvic floor disorders. It is obvious that magnetic resonance imaging has limitations in urogynecology and female urology at present due to cost and access limitations and due to the fact that it is generally a static, not a dynamic, method. However, none of those limitations apply to sonography, a diagnostic method that is very much part of general practice in obstetrics and gynecology. Translabial or transperineal ultrasound is helpful in determining residual urine; detrusor wall thickness; bladder neck mobility; urethral integrity; anterior, central, and posterior compartment prolapse; and levator anatomy and function. It is at least equivalent to other imaging methods in visualizing such diverse conditions as urethral diverticula, rectal intussusception, mesh dislodgment, and avulsion of the puborectalis muscle. Ultrasound is the only imaging method able to visualize modern mesh slings and implants and may predict who actually needs such implants. Delivery-related levator trauma is the most important known etiologic factor for pelvic organ prolapse and not difficult to diagnose on 3-/4-dimensional and even on 2-dimensional pelvic floor ultrasound. It is likely that this will be an important driver behind the universal use of this technology. This review gives an overview of the method and its main current uses in clinical assessment and research.

Delivery method, anal sphincter tears and fecal incontinence: new information on a persistent problem

PURPOSE OF REVIEW

To review the risk factors for anal sphincter tears during vaginal delivery and their association with fecal incontinence symptoms.

RECENT FINDINGS

Recent evidence links sphincter tears with fecal incontinence, which has a significant negative impact on quality of life. The Childbirth and Pelvic Symptoms cohort study reported that the incidence and severity of fecal incontinence was increased in primiparous women experiencing a sphincter tear. Risk factors for tear included forceps, occiput posterior, vacuum delivery, prolonged second stage of labor and epidural. Using cesarean delivery to prevent fecal incontinence has not been justified, but the confluence of these risk factors in the context of labor management may be important in deciding on earlier intervention with cesarean delivery. Internal anal sphincter defects impact fecal incontinence, highlighting the identification and repair of the internal anal sphincter for future research and clinical applications. Routine episiotomy (or instrumentation) is not warranted, and there is no clear advantage to mediolateral episiotomy or overlapping sphincter repair. Postpartum ultrasound of the sphincter complex may have an emerging role.

SUMMARY

The modifiable risk factors of routine episotomy and instrumented delivery are associated with sphincter tear; definitive recommendations for labor management remain unclear in preventing fecal incontinence.

The role of transperineal ultrasonography in the assessment of the internal opening of cryptogenic anal fistula

PURPOSE

The aim of this study was to assess the reliability of transperineal ultrasonography (TPUS) in the pre-operative identification of the internal opening of anal fistulas compared to conventional proctological examination and operative findings.

METHODS

Forty-three patients with anal fistula were assessed by TPUS with and without the use of hydrogen-peroxide injection (E-TPUS) in an attempt to identify the internal opening. Results were compared to preoperative conventional examination and operative findings.

RESULTS

Operative assessment showed an anterior internal opening in 29 patients (67.4%) and a posterior opening in 14 (32.6%). Compared to the operative findings, the agreement rate for the identification of the internal opening was 74.4% for physical examination alone, 93.0% for TPUS and 90.7% for E-TPUS. Physical examination was less accurate in detecting the internal opening than both TPUS (p=0.014) and E-TPUS (p=0.026).

CONCLUSIONS

TPUS and E-TPUS are superior to physical examination in the identification of internal openings in anal fistulas. Hydrogen peroxide injection does not provide additional advantages.

The clinical significance of postpartum transperineal ultrasound of the anal sphincter

BACKGROUND AND OBJECTIVE

To evaluate the clinical significance of postpartum anal sphincter damage by transperineal ultrasonography (TPUS) performed on the day of delivery.

METHODS

Continence questionnaires were handed out and TPUS was performed on 154 consecutive primiparous women 6-24h after vaginal delivery. At 2 and 6 months later, complaints and sphincteric sonographic appearance were reassessed. The puerperal women's clinical status and sonographic findings in the immediate and late postpartum period were evaluated.

RESULTS

Thirty-five (23%) women complained of anal incontinence on the first postpartum day and anal sphincter damage was demonstrated by TPUS in 31 (89%) of them. Four women with anorectal complaints had an intact anal sphincter by TPUS. Follow-up questionnaires, 2 months later, revealed 30 symptomatic women: all of them had sonographically recognized tears on the initial TPUS and 27 of them had positive findings on the TPUS performed 2 months after birth. Six months after delivery, 27 women reported symptoms and all of them had sphincteric disruption evidenced on TPUS performed on the day of delivery. All the women with intact sphincter on the initial TPUS were asymptomatic 6 months later.

CONCLUSION

TPUS findings on the day of delivery are related to long-term anorectal complaints, supporting a potential role for TPUS as a screening aid for anal sphincter tears.

Pelvic floor trauma following vaginal delivery

PURPOSE OF REVIEW

Recent years have seen a steady increase in the information available regarding pelvic floor trauma in childbirth. A review of this information is timely in view of the ongoing discussion concerning elective caesarean section.

RECENT FINDINGS

In addition to older evidence regarding pudendal nerve injury, it has recently been shown that inferior aspects of the levator ani and fascial pelvic organ supports such as the rectovaginal septum can be disrupted in childbirth. Such trauma is associated with pelvic organ prolapse, bowel dysfunction, and urinary incontinence. Elective caesarean section seems to have a limited protective effect that appears to weaken with time. Older age at first delivery may be associated with a higher likelihood of trauma and subsequent symptoms.

SUMMARY

Pelvic floor trauma is a reality, not a myth. It is currently not possible, however, to advise patients as to whether avoidance of potential intrapartum pelvic floor trauma is worth the risk, cost, and effort of elective caesarean section. In some women this may well be the case. The identification of women at high risk for delivery-related pelvic floor trauma should be a priority for future research in this field.

Translabial ultrasound assessment of the anal sphincter complex: normal measurements of the internal and external anal sphincters at the proximal, mid-, and distal levels

The purpose of this study was to measure the internal and external anal sphincters using translabial ultrasound (TLU) at the proximal, mid, and distal levels of the anal sphincter complex. The human review committee approval was obtained and all women gave written informed consent. Sixty women presenting for gynecologic ultrasound for symptoms other than pelvic organ prolapse or urinary or anal incontinence underwent TLU. Thirty-six (60%) were asymptomatic and intact, 13 symptomatic and intact, and 11 disrupted. Anterior-posterior diameters of the internal anal sphincter at all levels and the external anal sphincter at the distal level were measured in four quadrants. Mean sphincter measurements are given for symptomatic and asymptomatic intact women and are comparable to previously reported endoanal MRI and ultrasound measurements.

The role and applications of ultrasound in ambulatory gynaecology

Ultrasound has changed gynaecological practice and continues to do so. One of the earliest applications of abdominal scanning in gynaecology was for monitoring follicular development during fertility treatment with clomiphene citrate or gonadotrophins in the 1960s and 1970s. Subsequently, it was natural that with the introduction of in vitro fertilization, abdominal and transvaginal ultrasound played a key role in the development of oocyte retrieval techniques. These were truly the first interventional ultrasound-guided ambulatory procedures in gynaecology. In this chapter, the reader will be introduced to the roles that the various ultrasound modalities play in our current daily practice, and how they have changed the management of numerous gynaecological conditions in both diagnostic and therapeutic contexts. We will also outline the recent developments and the 'hot' research topics in this field.

Pelvic floor trauma in childbirth - myth or reality?

The issue of traumatic damage to the pelvic floor in childbirth is attracting more and more attention amongst obstetric caregivers and laypersons alike. This is partly due to the fact that elective Caesarean section, as a potentially preventative intervention, is increasingly available and perceived as safe. As there are a multitude of emotive issues involved, including health economics and the relative roles of healthcare providers, the discussion surrounding pelvic floor trauma in childbirth has not always been completely rational. However, after 25 years of urogynaecological research in this field it should be possible to determine whether pelvic floor trauma in childbirth is myth or reality. On reviewing the available evidence, it appears that there are sufficient grounds to assume that vaginal delivery (or even the attempt at vaginal delivery) can cause damage to the pudendal nerve, the caudal aspects of the levator ani muscle, fascial pelvic organ supports and the external and internal anal sphincter. Risk factors for such damage have been defined and variously include operative vaginal delivery, a long second stage, and macrosomia. It is much less clear, however, whether such trauma is clinically relevant, and how important it is in the aetiology of pelvic floor morbidity later in life.

Rigid overlay of volume sonography and MR image data of the female pelvic floor using a fiducial based alignment—feasibility due to a case series

The visual combination of different medical image acquisition techniques (modalities) can lead to new modalities with enhanced informative content. In this paper, we present an overlay technique of magnetic resonance (MR) and 3D US image data sets of the female anal canal (internal and external sphincter) as a base for a new diagnostic modality. It is a new field of the application of the overlay technique. Three corresponding MR and US volume data sets from the female pelvic floor region were filtered using adaptive filtering techniques and overlayed (=registered rigidly) with a landmark based alignment method.

Non-rigid registration of a 3D ultrasound and a MR image data set of the female pelvic floor using a biomechanical model

BACKGROUND

The visual combination of different modalities is essential for many medical imaging applications in the field of Computer-Assisted medical Diagnosis (CAD) to enhance the clinical information content. Clinically, incontinence is a diagnosis with high clinical prevalence and morbidity rate. The search for a method to identify risk patients and to control the success of operations is still a challenging task. The conjunction of magnetic resonance (MR) and 3D ultrasound (US) image data sets could lead to a new clinical visual representation of the morphology as we show with corresponding data sets of the female anal canal with this paper.

METHODS

We present a feasibility study for a non-rigid registration technique based on a biomechanical model for MR and US image data sets of the female anal canal as a base for a new innovative clinical visual representation.

RESULTS

It is shown in this case study that the internal and external sphincter region could be registered elastically and the registration partially corrects the compression induced by the ultrasound transducer, so the MR data set showing the native anatomy is used as a frame for the US data set showing the same region with higher resolution but distorted by the transducer

CONCLUSION

The morphology is of special interest in the assessment of anal incontinence and the non-rigid registration of normal clinical MR and US image data sets is a new field of the adaptation of this method incorporating the advantages of both technologies.

Simple ultrasound evaluation of the anal sphincter in female patients using a transvaginal transducer

OBJECTIVE

Fecal incontinence affects 0.2% of women aged 15-64 years and about 1.3% of women over 64 years. Most cases are related to instrumental deliveries affecting the anal sphincter complex. We propose a simple technique using the generally available transvaginal transducer to evaluate the anal sphincter complex.

METHODS

Ninety-two patients underwent ultrasound examination. Group I consisted of 53 nulliparous patients. In Group II there were six patients with normal spontaneous vaginal deliveries without episiotomies. In Group III there were 14 patients with vaginal deliveries and one to three episiotomies but no lacerations. In Group IV there were nine postpartum patients with recently repaired (48 h to 3 weeks) third- and fourth-degree lacerations. All women in Groups I-IV were asymptomatic. Group V consisted of 10 patients symptomatic for fecal incontinence. We used a vaginal probe (5-9-MHz) with the footprint placed in the fourchette pointing towards the anus in a transverse and then in a median (sagittal) plane. If seen, the combined internal and external anal sphincter thickness at the 12 o'clock location was measured. We visualized normal star-shaped mucosal folds on the transverse section and described the sonographic anatomy in both planes.

RESULTS

The mean sphincter thickness measured at 12 o'clock in Group I was 2.3 (range, 1.0-4.7) mm, in Group II it was 2.9 (range, 2.4-3.4) mm, and in Group III it was 2.3 (range, 1.0-3.7) mm. The differences between these three groups were not significant. Patients from Group IV showed thinning or discontinuous sphincter anatomy at the 12 o'clock position. All symptomatic patients from Group V showed abnormal sphincter anatomy, and the normal star-like appearance of the anal mucosa on the transverse section was deformed, radiating from the point of the sphincter damage. Four of the 10 patients in this group underwent surgical repair. In these patients the sonographic findings were confirmed.

CONCLUSIONS

The images obtained using this imaging modality show the sphincter muscle anatomy as well as the possible pathology. Due to its simplicity the technique can be applied in any place where a vaginal transducer is available.

Updated recommendations on ultrasonography in urogynecology

Ultrasound is a supplementary, indispensable diagnostic procedure in urogynecology; perineal, introital, and endoanal ultrasound are the most recommended techniques. The position and mobility of the bladder neck can be demonstrated. In patients undergoing diagnostic work-up for urge symptoms, ultrasound occasionally demonstrates urethral diverticula, leiomyomas, and cysts in the vaginal wall. These findings will lead to further diagnostic assessment. The same applies to the demonstration of bladder diverticula, foreign bodies in the bladder, and bullous edema. With endoanal ultrasound, different parts of the sphincter ani muscle can be evaluated. Recommendations for the standardized use of urogenital ultrasound are given.