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

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.

Immediate postpartum assessment of the anal sphincter by endovaginal ultrasound: An experimental study

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injuries are frequently missed and carry a significant risk for the development of anal incontinence. Immediate postpartum endoanal ultrasound increases identification of these injuries but is rarely employed. We hypothesize that endovaginal ultrasound could be a feasible and easily available alternative sonographic tool to improve early diagnosis of anal sphincter tears.

METHODS

We conducted a prospective experimental study including 160 primiparous women. Shortly after vaginal delivery, patients underwent clinical and sonographic perineal examinations. We analyzed the feasibility of anal sphincter assessment by endovaginal ultrasound and its potential contribution in the early diagnosis of anal sphincter injuries.

RESULTS

Sonographic assessment of the anal sphincter was analyzable for 136 patients (85.0%). Causes of non-analyzability included air artifacts (6.9%), lack of distinction between the external anal sphincter and surrounding tissues (9.4%) and distortion artifacts (9.4%). Patients in the non-analyzable ultrasound subgroup were less likely to have delivered in a dorsal lithotomy position (62.5% vs. 85.3 %) and more likely to have had an episiotomy (33.3% vs. 14.0%), and their risk of sphincter injury was more frequently classified as "improbable" on clinical examination (91.7% vs. 61.0%). Ultrasounds were analyzable for 96.4% of patients clinically reported as having "possible" or "certain" sphincter injuries. The incidence of anal sphincter injury was 16.9% for clinical observation and 20.0% with associated sonographic examination.

CONCLUSIONS

Endovaginal ultrasound could be used as a complementary tool in assessment of the anal sphincter in high-risk patients. Its feasibility and easy availability make this technique a promising tool for improving the management of anal sphincter tears.

Immediate postpartum assessment of the anal sphincter by endovaginal ultrasound: a new technical approach

INTRODUCTION AND HYPOTHESIS

In this study we described a new technical approach to adapt endovaginal ultrasound scanning of the anal sphincter complex to the immediate postpartum period.

METHODS

We analyzed the clinical and ultrasonographic examinations of 18 primiparous women presenting deep perineal tears with potential or clearly identified lesions of the anal sphincter. Potential anal sphincter lesion was defined as a second degree perineal tear extending close to the anal sphincter with exposition of its capsule or muscular fibers. We reported interesting ultrasonographic images explaining our technique in a video.

RESULTS

We reported clinical and ultrasonographic features in nine cases of grade 2, four cases of grade 3a, four cases of grade 3b and one case of grade 3c perineal tears. The ultrasonographic examination confirmed the intact state of the anal sphincter complex in all patients with clinical grade 2 tears except one in which a grade 3b lesion was detected. We were not able to identify external anal sphincter lesions on ultrasound in any of the patients with clinical grade 3a tears. In patients with clinical grade 3b tears, the ultrasound confirmed the external anal sphincter lesion in all cases, but revealed additional involvement of the internal anal sphincter in 1 case (grade 3c).

CONCLUSION

Immediate postpartum endovaginal ultrasound could be a promising technique to improve the management of perineal traumas after vaginal delivery.

International Urogynecological Consultation: clinical definition of pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

This segment of Chapter 1 of the International Urogynecology Consultation (IUC) on pelvic organ prolapse (POP) reviews the literature on the clinical definition of POP with the intent of creating standard terminology.

METHODS

An international group containing nine urogynecologists and one university-based medical librarian performed a search of the literature using pre-specified search terms in PubMed, Embase, and Scopus. Publications were eliminated if not relevant to the clinical definition of POP, and those articles remaining were evaluated for quality using the Specialist Unit for Review Evidence (SURE). The resulting list of articles was used to inform a comprehensive review and creation of the clinical definition of POP.

RESULTS

The original search yielded 31,931 references, of which 167 were used by the writing group. Ultimately, 78 are referenced in the manuscript.

CONCLUSIONS

The clinical definition of POP for this review of the literature is: "anatomical prolapse with descent of at least one of the vaginal walls to or beyond the vaginal hymen with maximal Valsalva effort WITH the presence either of bothersome characteristic symptoms, most commonly the sensation of vaginal bulge, or of functional or medical compromise due to prolapse without symptom bother."

Perineorrhaphy Compared With Pelvic Floor Muscle Therapy in Women With Late Consequences of a Poorly Healed Second-Degree Perineal Tear: A Randomized Controlled Trial

OBJECTIVE

To evaluate outcomes after pelvic floor muscle therapy, as compared with perineorrhaphy and distal posterior colporrhaphy, in the treatment of women with a poorly healed second-degree obstetric injury diagnosed at least 6 months postpartum.

METHODS

We performed a single center, open-label, randomized controlled trial. After informed consent, patients with a poorly healed second-degree perineal tear at minimum 6 months postpartum were randomized to either surgery or physical therapy. The primary outcome was treatment success, as defined by Patient Global Impression of Improvement, at 6 months. Secondary outcomes included the Pelvic Floor Distress Inventory, the Pelvic Floor Impact Questionnaire, the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire, and the Hospital Anxiety and Depression Scale. Assuming a 60% treatment success in the surgery group and 20% in the physical therapy group, plus anticipating a 20% loss to follow-up, a total of 70 patients needed to be recruited.

RESULTS

From October 2015 to June 2018, 70 of 109 eligible patients were randomized, half into surgery and half into tutored pelvic floor muscle therapy. The median age of the study group was 35 years, and the median duration postpartum at enrollment in the study was 10 months. There were three dropouts in the surgery group postrandomization. In an intention-to-treat analysis, with worst case imputation of missing outcomes, subjective global improvement was reported by 25 of 35 patients (71%) in the surgery group compared with 4 of 35 patients (11%) in the physical therapy group (treatment effect in percentage points 60% [95% CI 42-78%], odds ratio 19 [95% CI 5-69]). The surgery group was superior to physical therapy regarding all secondary endpoints.

CONCLUSION

Surgical treatment is effective and superior to pelvic floor muscle training in relieving symptoms related to a poorly healed second-degree perineal tear in women presenting at least 6 months postpartum.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02545218.

Accuracy of clinical diagnosis of anal sphincter defect: clinical evaluation versus 3D-transperineal ultrasound

BACKGROUND

Obstetric anal sphincter injuries (OASIS) are common and an important factor in the etiology of anal incontinence. The objective of this study was to evaluate, classify and compare the agreement of clinically diagnosed third-degree sphincter tears with 3D-transperineal ultrasound (3D-TPUS) realized within 3-7 days post-delivery.

METHODS

This is a retrospective observational study were 119 patients with third-degree obstetric anal sphincter tears were diagnosed and treated, 85 of those underwent a 3D-TPUS examination 3-7 days postpartum. We compared the proportion of third-degree perineal tears, classified with the clinical examination as grade 3a+b and grade 3c, with the 3D-TPUS.

RESULTS

In 16 patients with clinically diagnosed third-degree perineal tears grade a and b, the ultrasound examination confirmed the lesion of the external anal sphincter (EAS) muscle, but in nine patients (56% of the cases) we found a lesion of the internal anal sphincter (IAS) muscle, missed by clinical examination. In the remaining 69 patients with the third-degree perineal tears grade c, the ultrasound examination confirmed both lesions (EAS and IAS muscles) in 56 women, but in 13 patients (19% of the cases) defects of the IAS muscle could not be confirmed by the ultrasound.

CONCLUSIONS

There was moderate agreement regarding diagnosis of grade 3a+b and grade c perineal tears between ultrasound and clinical examination, so a combined use of clinical and ultrasound knowledge can improve the possibility to find a gold standard in the diagnosis of OASIS.

Is endoanal, introital or transperineal ultrasound diagnosis of sphincter defects more strongly associated with anal incontinence?

INTRODUCTION AND HYPOTHESIS

Our aim was to explore the association between anal incontinence (AI) and persistent anal sphincter defects diagnosed with 3D endoanal (EAUS), introital (IUS) and transperineal ultrasound (TPUS) in women after obstetric anal sphincter injury (OASI) and study the association between sphincter defects and anal pressure.

METHODS

We carried out a cross-sectional study of 250 women with OASI recruited during the period 2013-2015. They were examined 6-12 weeks postpartum or in a subsequent pregnancy with 3D EAUS, IUS and TPUS and measurement of anal pressure. Prevalence of urgency/solid/liquid AI or flatal AI and anal pressure were compared in women with a defect and those with an intact sphincter (diagnosed off-line) using Chi-squared and Mann-Whitney U test.

RESULTS

At a mean of 23.6 (SD 30.1) months after OASI, more women with defect than those with intact sphincters on EAUS had AI; urgency/solid/liquid AI vs external defect: 36% vs 13% and flatal AI vs internal defect: 27% vs 13%, p < 0.05. On TPUS, more women with defect sphincters had flatal AI: 32% vs 13%, p = 0.03. No difference was found on IUS. Difference between defect and intact sphincters on EAUS, IUS and TPUS respectively was found for mean [SD] maximum anal resting pressure (48 [13] vs 55 [14] mmHg; 48 [12] vs 56 [13] mmHg; 50 [13] vs 54 [14] mmHg) and squeeze incremental pressure (33 [17] vs 49 [28] mmHg; 37 [23] vs 50 [28] mmHg; 36 [18] vs 50 [30] mmHg; p < 0.01).

CONCLUSIONS

Endoanal ultrasound had the strongest association with AI symptoms 2 years after OASI. Sphincter defects detected using all ultrasound methods were associated with lower anal pressure.

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.

Normal Values of Anal Sphincter Biometry by 4-Dimensional Translabial Ultrasound: A Retrospective Study of Pregnant Women in Their Third Trimester

OBJECTIVES

Exoanal 4-dimensional translabial ultrasound (TLUS) is increasingly used to image the anal sphincter. The aim of this study was to define the limits of normality for assessment of external and internal anal sphincters with TLUS.

METHODS

This study was a retrospective analysis using data sets of nulliparous women seen antenatally. All women had a 4-dimensional TLUS examination at a mean gestational age ± SD of 36 ± 0.7 (range, 32.9-37.3) weeks. Anal sphincter biometry, including external anal sphincter (EAS) length and thickness, EAS proximal rotational asymmetry, and internal anal sphincter thickness, was assessed blinded against other data.

RESULTS

A test-retest series showed good repeatability (intraclass correlation coefficients, 0.619-0.849) of all parameters. The mean age of the women (n = 111) was 30.9 (range, 18.8-40.5) years. None reported anal incontinence. On tomographic imaging, none showed anal sphincter defects. The mean EAS length was 17.5 (range, 8.4-34.8) mm, being shorter dorsally at 16.4 (range, 7.0-32.7) mm versus 18.7 (range, 7.5-36.9) mm ventrally (P < .001). The ventral EAS reached farther cranially by 0.8 ± 2.5 (range, -4.8-5.1) mm on average. The mean EAS thickness was 3.4 (range, 2.0-5.8) mm, being thicker dorsally than ventrally (P < .001).

CONCLUSIONS

Anal sphincter biometry can be assessed with good repeatability by TLUS. The EAS seems longer ventrally. Asymmetry of the EAS could result in a false-positive diagnosis of defects in women in whom the ventral EAS terminates more caudally than its dorsal aspect, which seems uncommon. Hence, the likelihood of a false-positive diagnosis of substantial defects of the EAS using the published method seems low.

High-frequency ultrasound imaging of the anal sphincter muscles in normal subjects and patients with fecal incontinence

INTRODUCTION

The current "gold standard" to diagnose anal sphincter morphology and disruptions utilizes low-frequency (3-9 MHz) ultrasound (US) imaging techniques that provide a general outline of the sphincter muscles, but not their microstructural details. High-frequency US transducers (7-15 MHz) have been used to study the muscle architecture (direction of muscle fascicles) in the limb muscle.

AIMS

The goal of our study was to visualize the microstructural anatomy of the anal sphincters, specifically the external anal sphincter (EAS), using high-frequency US imaging.

METHODS

Studies were conducted in asymptomatic female and male subjects and patients with fecal incontinence. US images were acquired using a low-frequency US (3-9 MHz) and high-frequency (7-15 MHz) US transducer. The latter was placed intra-anally to image the anal canal at 12, 9, 3, and 6 o'clock positions.

RESULTS

The low-frequency US images revealed the general outline of the anal sphincter muscles. On the other hand, high-frequency imaging visualized muscle fascicles and connective tissue inside the external anal sphincter (EAS). In FI patients, there was loss of muscle fascicles and alteration in the echo-intensity pattern in the region of damaged EAS suggestive of muscle fibrosis.

CONCLUSION

High-frequency ultrasound imaging is a powerful tool to visualize the microstructural details of the EAS. Our studies show that damage to the EAS muscle results in the alteration of its myoarchitecture, that is, loss of muscle fascicles and increase in the muscle connective tissue.

Anovaginal distance and obstetric anal sphincter injury: a prospective observational study

INTRODUCTION AND HYPOTHESIS

No measurements are available for diagnosing the extent of obstetric lacerations. The primary aim of this study was to evaluate the relation between the anovaginal distance (AVD) measured with transperineal ultrasound immediately after delivery and external anal sphincter injury. A secondary aim was to assess whether the palpated perineal thickness was associated with the AVD.

METHODS

A prospective observational study of 150 primiparous women at the University Hospital, Linköping, Sweden. After vaginal delivery, initial inspection and palpation of the perineal thickness were performed by the midwife. The women were then divided into subgroups depending on the degree of the suspected perineal laceration. Transperineal ultrasound of the AVD was performed by a physician. Diagnostics of the perineal laceration were done according to standard care.

RESULTS

Women with an external sphincter injury had a shorter AVD and shorter palpatory perineal thickness compared with women without anal sphincter injury. No external sphincter injuries were diagnosed when the AVD and/or palpation height was &gt; 20 mm. The mean AVD in the group with probable second-degree laceration (n = 85) was 18.8 mm (95% CI 17.8-19.8), in suspected third-degree laceration (n = 33) 15.7 mm (95% CI 13.7-17.7) and in probable third-degree laceration (n = 32) 11.8 mm (95% CI 9.7-13.9) (p &lt; 0.001).

CONCLUSIONS

A short AVD could be a warning sign postpartum and should increase the awareness of possible external sphincter injury before suturing. An AVD of 20 mm seems to indicate a cutoff level of the occurrence of external sphincter injury, but this needs further evaluation.

Maternal Body Mass Index and Anovaginal Distance in Active Phase of Term Labor

Introduction

To evaluate if there was a difference in the anovaginal distance (AVD) measured by transperineal ultrasound between obese and normal weight women.

Material and Methods

A prospective observational study including 207 primiparous women at term in first stage of labor. Transperineal ultrasound with a vaginal probe was used to measure the AVD. Maternal, pregnancy, and delivery characteristics potentially associated with perineal thickness were extracted from woman's medical records. The participants were divided into three BMI groups based on maternal weight in early pregnancy: normal weight (BMI < 25), overweight (BMI 25–29.9), and obesity (BMI ≥ 30). Obese and overweight women were compared with normal weight women regarding the AVD.

Results

The mean AVD was 24.3, 24.9, and 27.0 mm in the normal weight, overweight, and obesity group, respectively. There were no group differences in background characteristics. The AVD was significantly longer in obese women compared with normal weight women (p = 0.018).

Conclusions

The observed longer AVD in obese women might be protective of the anal sphincter complex, explaining lower rates of anal sphincter injuries in this group. Further studies are indicated to evaluate whether the length of the AVD plays a role in the risk assessment of obstetric anal sphincter injury. The trial is registered in ClinicalTrials.gov and the trial registration ID is NCT03149965.

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.

Interobserver agreement in perineal ultrasound measurement of the anovaginal distance: a methodological study

INTRODUCTION AND HYPOTHESIS

Objective outcome measures of the extent of laceration at delivery are needed. In this study we evaluated and describe here a method for learning perineal ultrasound measurement of the anovaginal distance (AVD). The learning period needed for examiners proficient in vaginal ultrasound examination and the interobserver agreement after reaching proficiency in AVD measurement were determined. The hypothesis was that the method is feasible to learn and reproducible for use in further research.

METHODS

The method was taught by an examiner experienced in perineal ultrasonography. The distance between the mucosal margin of the internal anal sphincter was measured with a vaginal probe. The studied examiners measured the AVD until similar results (±5 mm) were achieved. The AVD in 40 women was then measured and documented by two examiners who were blinded to each other's results. Interobserver agreement was calculated using the kappa score.

RESULTS

Examiners with previous experience in vaginal ultrasonography had learned the method after performing five sets of comeasurements. The AVD measurements after the learning period showed almost perfect agreement (κ = 0.87) between the examiners.

CONCLUSIONS

The method for perineal ultrasound measurement of AVD was learned quickly with high interobserver agreement. The method is feasible to learn and reproducible for use in further research.

The immediate effect of vaginal and caesarean delivery on anal sphincter measurements

Objective

This study evaluated the effects of vaginal and caesarean delivery on internal and external anal sphincter muscle thickness using translabial ultrasonography (TL-US).

Methods

This prospective cohort study enrolled nulliparous women who either had vaginal or caesarean deliveries. The thickness of the hypoechoic internal anal sphincter (IAS) and hyperechoic external anal sphincter (EAS) at the 12, 3, 6, and 9 o’clock positions at the distal level were measured before delivery and within 24–48 h after delivery.

Results

A total 105 consecutive women were enrolled in the study: 60 in the vaginal delivery group and 45 in the caesarean delivery group. The IAS muscle thickness at the 12 o’clock position in the vaginal delivery group was significantly thicker before compared with after delivery (mean ± SD: 2.31 ± 0.74 mm versus 1.81 ± 0.64 mm, respectively). The EAS muscle thickness at the 12 o’clock position in the vaginal delivery group was significantly thicker before compared with after delivery (mean ± SD: 2.42 ± 0.64 mm versus 1.97 ± 0.85, respectively).

Conclusions

There was significant muscle thinning of both the IAS and EAS at the 12 o’clock position after vaginal delivery, but not after caesarean delivery.

Transvaginal sonographic features of perineal masses in the female lower urogenital tract: a retrospective study of 71 patients

OBJECTIVES

To assess the transvaginal ultrasonographic features of perineal masses in the lower urogenital tract in a cohort of 71 women.

METHODS

Seventy-one women with perineal masses were referred consecutively for transvaginal ultrasonography. Two-dimensional (2D) ultrasound was used to scan the pelvic floor, including the urethra, vagina and rectum, and identify any possible areas of interest. A static three-dimensional (3D) sonographic reconstruction of the pelvic anatomy was created to further delineate the relation of the lesions with their neighboring structures. Ultrasound results were compared retrospectively with surgical pathology outcome when possible.

RESULTS

Seventy-nine cystic, cystic-solid or solid masses were detected on transvaginal 2D ultrasonography in the 71 women: in 44 patients, 47 anechoic cystic masses were identified and diagnosed as vaginal wall cysts; in 19 patients, 23 hyperechoic cystic masses were diagnosed as vaginal epidermoid cysts; in each of two patients, a hypoechoic cystic-solid mass showing blood-flow signals on color Doppler imaging was diagnosed as urogenital angiomyofibroblastoma; in each of three patients, a hypoechoic cyst was diagnosed as urethral diverticulum; and in three patients with a known history of gynecological malignancy, solid heterogeneous masses with blood flow signals on color Doppler imaging were diagnosed as metastatic cancer. In all patients, 3D ultrasonography delineated the anatomical relationship of these masses to the vagina, urethra and rectum.

CONCLUSIONS

Transvaginal 2D and 3D ultrasonography is an accurate, non-invasive, cost-effective diagnostic modality for the delineation of congenital, septic and neoplastic lower urogenital tract perineal masses in women.

Development of the maternal anal canal during pregnancy and the postpartum period: a longitudinal and functional ultrasound study

OBJECTIVES

Normal anatomical and physiological development of the maternal anal canal during and after pregnancy has been documented scarcely. We aimed to study the position and volume of the anal canal, during and after pregnancy, in women without previous delivery.

METHODS

This was a longitudinal study in which transvaginal three-dimensional ultrasound was used to measure anatomical structures in the anal canal during rest and squeeze in 23 nulliparous women. The total anal canal volume (ACV), anorectal curvature (ARC), anovaginal angle (AVA) and anal canal length were determined at 18, 28 and 36 weeks of pregnancy and at 3 months postpartum.

RESULTS

Total ACV at rest increased from a mean of 10.17 cm(3) at 18 weeks to 12.37 cm(3) and 12.21 cm(3) at 28 and 36 weeks, respectively (P = 0.001 and P = 0.010 vs. first measurement). For anal canal length, the corresponding mean measurements were 3.91 cm, 4.07 cm (P = 0.13) and 4.21 cm (P = 0.017). Postpartum, the mean total ACV was 10.86 cm(3) and length was 3.90 cm (P = 0.10 and P = 0.70 vs. first measurement). No significant changes were observed in ARC and AVA during or after pregnancy. Compared to at-rest status, the anal length significantly increased on voluntary squeeze (P = 0.007, 0.007, 0.022 and 0.004 at the four time points), while no differences in total ACV were observed. In mid-pregnancy AVA significantly increased during squeeze (P = 0.006 and 0.002 at weeks 18 and 28, respectively).

CONCLUSION

Anal canal length and total ACV increase during pregnancy in women without previous delivery. Voluntary squeezing elongates the anal canal and increases the angle formed with respect to the direction of the vagina. During postpartum involution, the characteristics of the anal canal revert to those observed at 18 weeks of pregnancy.

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.

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.

Transvaginal three-dimensional ultrasound: a method of studying anal anatomy and function

OBJECTIVES

To explore the possibility of using transvaginal 3D ultrasound as a method of assessing the compartments of the anal canal during rest, to determine the effect of squeeze, and to compare these findings with those obtained using the endoanal technique in the same women.

METHODS

Transvaginal 3D ultrasound was used in a cross-sectional study measuring the anal mucosa and sphincters during rest and squeeze in 20 nulligravida women, comparing the results with those of endoanal measurements. Measurements were also performed of the anal mucosa, anorectal curvature (ARC), and anovaginal angle (AVA) and distance (AVD).

RESULTS

Volume measurements of the anal mucosa were only possible using transvaginal ultrasound. The mean volume of the anal canal using the transvaginal technique was 7.93 (SD 2.26) and 7.34 (1.54) cm(3) during rest and squeeze, respectively (P = 0.082). The ARC became more acute (3.46 vs. 4.12°/mm, P = 0.031) during squeeze and AVA increased (31.7° vs. 35.8°, P = 0.010). The volume of the anal mucosa (3.12 cm(3)) did not change (P = 0.193), but was distorted during squeeze at the level of the puborectalis sling (P < 0.001 for upper cross-section and diameter). The anal canal was 1 cm longer (P < 0.001), the IAS volume larger (2.97 and 2.08 cm(3), P = 0.003), and the EAS volume smaller (1.85 and 3.96 cm(3), P < 0.001) using the 3D transvaginal technique compared with the endoanal measurements at rest, with similar differences observed on squeeze.

CONCLUSION

In contrast to the endoanal method, transvaginal 3D ultrasound provides a complete assessment of the anal canal, including the mucosa. This method seems suitable for functional studies such as in the present one, which shows that voluntary squeeze increases the angulation of the anal canal and distorts the bowel cross-section at the level of the puborectal muscle.

Sonographic depiction of the fetal anus and its utility in the diagnosis of anorectal malformations

OBJECTIVES

The purpose of this study was to describe the sonographic appearance of the fetal anus and its usefulness in diagnosis of anal atresia.

METHODS

An anomaly scan was performed in 13,150 patients over 8 years. Gestational ages ranged from 16 to 38 weeks. A tangential scan of the fetal perineum was performed. The anus was seen as a hypoechoic ring representing the wall of the anal canal with a central echogenic dot representing the lumen. This appearance was seen posterior to the external genitalia. If there was failure to see this appearance, a coronal scan of the fetal pelvis was done to look for the anal canal in contiguity with the rectum and to confirm its extension up to perineum. Failure to see these two features was considered diagnostic of anal atresia.

RESULTS

On the basis of these criteria, anal atresia was diagnosed in 17 fetuses. Sixteen of these fetuses also had other associated anomalies. The appearance of the anus was useful for ruling out anal atresia in 2 fetuses with a dilated colon containing echogenic meconium balls.

CONCLUSIONS

The anus is visible on a tangential scan of the fetal perineum. It can be seen routinely during an anomaly scan to diagnose or rule out anal atresia.

Imaging pelvic floor dysfunction

Pelvic floor function and structure are complex, and imaging (integrated with an understanding of physiology) is central to guiding the clinician in managing patients with incontinence, constipation, difficult rectal evacuation and pelvic organ prolapse. Multimodal imaging techniques such as static and dynamic imaging techniques (sometimes combined in a single sitting) have revolutionised our understanding of functional anatomy. The advent of endo-luminal imaging has increased our spatial resolution by its closer proximity to the area of interest. Dynamic imaging gives us a near physiological data set which helps us to simulate what is likely to happen in real life and gives us a better understanding of the multifactorial causes, and consequences, of pelvic floor dysfunction.

High-resolution three-dimensional endovaginal ultrasonography in the assessment of pelvic floor anatomy: a preliminary study

INTRODUCTION AND HYPOTHESIS

Our aim was to evaluate the morphological characteristics of the female pelvic floor that may be further elucidated with three-dimensional endovaginal ultrasonography (3D-EVUS).

METHODS

A consecutive series of 20 nulliparous females underwent 3D-EVUS. Measurements were determined according to pre-established criteria. Descriptive statistics and Spearman's correlation test were performed.

RESULTS

The levator hiatus (LH) was measured in the oblique plane parallel to the pubovisceral muscle. A positive correlation was found between LH area and age (p = 0.03). The anteroposterior diameter of the urogenital hiatus, measured in the axial plane tilted from the symphysis pubis to the ischiopubic rami, correlated with LH area (p = 0.008). No urethral rotations were observed in the coronal plane. Significant correlations were found among urethral parameters. Mean anal sphincter measurements were comparable to previously reported magnetic resonance imaging and ultrasound measurements.

CONCLUSIONS

3D-EVUS allows measurements of key pelvic floor structures in planes that cannot be determined by conventional imaging modalities.

Transperineal three-dimensional ultrasound imaging for detection of anatomic defects in the anal sphincter complex muscles

BACKGROUND & AIMS

Three-dimensional ultrasound (3D-US) imaging is a powerful tool to visualize various components of the anal sphincter complex, that is, the internal anal sphincter (IAS), the external anal sphincter (EAS), and the puborectalis muscle (PRM). Our goal was to determine the reliability of the 3D-US imaging technique in detecting morphologic defects in the IAS, EAS, and PRM.

METHODS

Transperineal 3D-US images were obtained in 3 groups of women: nulliparous (n = 13), asymptomatic parous (n = 20), and patients with fecal incontinence (FI) (n = 25). The IAS and EAS were assessed to determine the craniocaudal length of defects and were scored as follows: 0 = normal, 1 = less than 25%, 2 = 25% to 50%, 3 = 50% to 75%, and 4 = greater than 75%. The 2 PRM hemislings were scored separately as follows: 0 = normal, 1 = less than 50% abnormal, and 2 = greater than 50% length abnormal. Subjects were grouped according to the score as follows: normal (score 0), minor abnormality (scores of 1 and 2), and major abnormality (scores of 3 and 4). Three observers performed the scoring.

RESULTS

The 3D-US allowed detailed evaluation of the IAS, EAS, and PRM. The inter-rater reliability for detecting the defects ranged between 0.80 and 0.95. Nullipara women did not show any significant defect but the defects were quite common in asymptomatic parous and FI patients. The prevalence of defects was greater in the FI patients as compared with the asymptomatic parous women.

CONCLUSIONS

3D-US yields reliable assessment of morphologic defects in the anal sphincter complex muscles.

Radiologic evaluation of pelvic floor disorders

Several imaging modalities are available ranging from fluoroscopic techniques to ultrasonography and MRI for the evaluation of patients with pelvic floors disorders. High-resolution ultrasonography and MRI not only provide superior delineation of the pelvic floor anatomy but also reveal pathology and functional changes. This article focuses on standard imaging procedures including defecography, ultrasonography, and MRI and discusses its use in clinical practice by illustrating both normal and abnormal patterns.

Three-dimensional transperineal ultrasonography of the pelvic floor: improving visualization for new clinical applications and better functional assessment

OBJECTIVE

With increasing awareness of the scope of pelvic floor disorders has come development and introduction into clinical practice of new imaging techniques, with increasing importance of ultrasonography. Complex pelvic floor anatomy, the conceptual difficulty in the basics of some pelvic floor disorders, and the uneven standardization of ultrasonographic techniques were the impetuses of this review. The purpose of this study was to review the basic anatomy of the pelvic floor and the transperineal ultrasonographic evaluation technique and to provide an overview of the current clinical use of 3-dimensional transperineal ultrasonography in the evaluation of the anterior and posterior pelvic floor compartments.

METHODS

A literature review illustrated with index cases from our center was conducted.

RESULTS

Ultrasonography has been widely applied to evaluation of the anterior and posterior compartments of the pelvic floor. Three-dimensional ultrasonography has a role in improving pelvic floor assessment.

CONCLUSIONS

Three-dimensional transperineal ultrasonography has been applied to evaluation of normal and pathologic pelvic floor anatomy. Practical application, through well-designed and sufficiently powered clinical studies, will establish the association between the clinical presentations of dysfunction with ultrasonographic findings.

Transperineal three-dimensional ultrasound in evaluating anal sphincter muscles

OBJECTIVES

To evaluate whether transperineal three-dimensional (3D) ultrasound can be used to depict normal anal sphincter anatomy and to measure the thickness of muscle layers and the anteroposterior length of the levator hiatus.

METHODS

The study included 22 normal nulliparous female volunteers. Transperineal 3D sonographic evaluation of the anal canal included assessment of sphincter shape, echogenicity, marginal definition and muscle thickness. Measurements of the thickness of the internal anal sphincter (IAS) and puborectalis muscle (PRM) were determined with the women at rest and during squeezing by two observers, and interobserver reliability was determined. The anteroposterior length of the levator hiatus at rest and during squeezing was measured.

RESULTS

The proximal end of the anal canal (towards the rectum) consisted of overlapping IAS and PRM, and the distal end (towards the anus) consisted of overlapping IAS and external anal sphincter (EAS). At the PRM level, the mean +/- SD IAS thickness was 2.3 +/- 0.5 mm at rest and 2.5 +/- 0.4 mm during squeezing, and at the mid-EAS level it was 2.9 +/- 0.5 mm at rest and 2.8 +/- 0.5 mm during squeezing. The PRM thickness was 6.5 +/- 1.0 mm at rest and 6.4 +/- 1.2 mm during squeezing. The difference in muscle thickness of the sphincter layers with the woman at rest and during squeezing was not significant. The anteroposterior length of the levator hiatus was 51.7 +/- 5.0 mm at rest and 47.4 +/- 4.1 mm during squeezing (P < 0.01).

CONCLUSION

Transperineal 3D ultrasound may be useful in evaluating the anatomy of the anal canal.

Three-dimensional transperineal sonographic characteristics of the anal sphincter complex in nulliparous women

OBJECTIVE

To explore the morphological characteristics and normal biometry of the anal sphincter complex in nulliparous Chinese women using three-dimensional (3D) transperineal ultrasound.

METHODS

3D sonographic data from 55 nulliparous Chinese women (aged 19-38 years) who had no pelvic organ prolapse and no symptoms of pelvic floor dysfunction were retrieved from an image dataset and analyzed by offline post-processing. The morphological characteristics of the external and internal anal sphincters, puborectalis muscle and perineal body were assessed in the sagittal, coronal and axial views.

RESULTS

The external anal sphincter had three sonographic components: the circular main body, a subcutaneous part and an extension portion. It was significantly thinner at 12 o'clock than at the 3, 6 and 9 o'clock positions. The internal anal sphincter was seen as dark echolucent strips of equal thickness. In the mid-sagittal view, it started from the anal verge and ended at the anorectal junction. The perineal body was an ovoid structure covering the upper margin of the external sphincter, while the puborectalis muscle was banana-shaped in the sagittal view and was located behind the anorectal junction, extending downward along the inferior margin of the posterior external sphincter extension. Sonographic characteristics of the anal sphincter complex did not vary with age, weight, height or body mass index.

CONCLUSIONS

3D transperineal ultrasound clearly demonstrates the spatial relationships of each component of the anal sphincter complex. This should allow standardized measurement of the complex for investigations of its function.

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.

Posterior pelvic floor disorders: a prospective comparison using introital ultrasound and colpocystodefecography

OBJECTIVE

To compare introital ultrasound with colpocystodefecography (CCD) in quantifying the anorectal angle and in the diagnosis of posterior pelvic floor disorders.

METHODS

Forty-three consecutive women with functional impairment of the posterior pelvic floor were enrolled after a clinical evaluation. Using both CCD and introital ultrasound examination, the anorectal angle was measured during squeezing to evaluate the strength of voluntary muscle contraction and during straining to assess pelvic floor relaxation. Rectocele depth and the presence of intussusception were assessed. The performance of CCD and that of introital ultrasound were compared.

RESULTS

Good concordance was obtained between introital ultrasound and CCD. The intraclass correlation coefficient was 0.82 (95% CI, 0.69-0.89) for measurement of the anorectal angle during squeezing and 0.67 (95% CI, 0.47-0.81) during straining. Rectoceles > 4 cm on CCD were detected by introital ultrasound in 100% of cases, and there was 91% agreement for rectal intussusception. Cohen's kappa index was moderate for rectocele assessment (0.41, P < 0.01) and excellent for intussusception (0.91, P < 0.001). It was also noted that introital ultrasound could be used to detect pelvic floor dyssynergia.

CONCLUSIONS

Introital ultrasound is a simple, accurate, non-invasive method with which to assess anorectal dynamics.

Postpartum evaluation of the anal sphincter by transperineal three-dimensional ultrasound in primiparous women after vaginal delivery and following surgical repair of third-degree tears by the overlapping technique

OBJECTIVE

Intrapartum damage to the anal sphincter is an important factor in fecal incontinence. Recognized lacerations occur in 0.36-8.4% of vaginal deliveries, and occult sphincter damage in up to 35% of primiparous women. We examined the role of three-dimensional transperineal ultrasound (3DTUS) in the evaluation of the anal sphincter in primiparous women after vaginal delivery and after surgical repair of third-degree intrapartum tears by the overlapping technique.

METHODS

During 2004-2005 139 primiparous women without clinically recognized third- to fourth-degree anal sphincter tears were prospectively studied 24-72 h postpartum (Group 1) and 13 primiparous women were examined 48 h to 4 months following surgical repair of third-degree tears with the overlapping technique (Group 2). A 3D 5-9-MHz transvaginal probe was placed in the area of the fourchette and perineal body in transverse and sagittal planes and 2-4 volumes were stored. The parameters studied were: examination duration; continuity of the internal and external sphincters; occult sphincter damage; internal sphincter and external sphincter width-measured 1.5 cm from the distal margin of the anus-at the '12, 3, 6 and 9 o'clock positions'; length of the posterior internal sphincter.

RESULTS

Scanning was possible in all women and the stored volumes were adequate in 127/139 (91.4%) cases. Mean examination time was 3.5 min. In Group 1, occult sphincter defect was suspected in 10/127 women (7.9%). These patients were excluded from measurement calculations, leaving 117 cases for analysis. The internal sphincter was consistently visualized in all the remaining patients (n = 117), while the external sphincter was fully visualized in 99/117 women (84.6%), and partially visualized in the remainder. Mean internal sphincter thickness was 2.60, 2.55, 2.60 and 2.72 mm at the 12, 3, 6 and 9 o'clock positions, respectively, and mean internal sphincter length was 3.34 cm. Mean external sphincter thickness was 4.15, 4.20, 4.21 and 4.20 mm at the 12, 3, 6 and 9 o'clock measurement points. In Group 2, 3DTUS confirmed anatomic abnormalities in all the women in the area surrounding the 12 o'clock position. Evaluation of sphincter tears and their position and length was possible using the longitudinal view. Thinning of the internal sphincter in the area of damage and thickening on the opposite side, the 'half moon sign', sphincter discontinuity, thickening of the external sphincter in the area of repair and abnormality of mucous folds, seemed to be common signs of third-degree intrapartum sphincter tears, even after repair.

CONCLUSIONS

3DTUS is an accessible and promising method for postpartum sphincter evaluation, that is apparently well tolerated by patients. Reference data for sphincter anatomy representative of findings at transperineal ultrasound in primiparous women in the postpartum period have been established.

Measurement of the anal cushions by transvaginal ultrasonography

PURPOSE

The anal cushions are believed to contribute to the anal continence mechanism. Transvaginal ultrasound previously has been used to visualize the anal sphincters. Using this method, visualization of the anal cushions has been described but no quantitation of the cushions has been undertaken. Because impairment of the anal cushion function may lead to anal incontinence, this study was designed to evaluate the use of transvaginal ultrasound to measure the anal cushions.

METHODS

Patients attending a gynecologic ultrasound list were recruited into the study. By measuring cross-sectional areas, a cushion:canal ratio was calculated.

RESULTS

Fifty females were studied. Results showed that the area enclosed within the internal anal sphincter had a median of 2.37 cm(2) (interquartile range, 1.76-2.61). The cushion:canal ratio was 0.66 (interquartile range, 0.57-0.7). Interobserver error was 0.98 and intraobserver error 0.99.

CONCLUSIONS

In this pilot study, we conclude that transvaginal ultrasonography is a reliable method of measuring the anal cushions in healthy control subjects. A narrow normal range can be established. This may be compared later with anal cushion size in patients who have symptoms of incontinence and may be used to assess changes in the size of the cushions in response to recently described anal cushion bulking agents.