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

A biomechanical perspective on perineal injuries during childbirth

BACKGROUND AND OBJECTIVE

Childbirth trauma is a major health concern that affects millions of women worldwide. Severe degrees of perineal trauma, designated as obstetric anal sphincter injuries (OASIS), and levator ani muscle (LAM) injuries are associated with long-term morbidity. While significant research has been conducted on LAM avulsions, less attention has been given to perineal trauma and OASIS, which affect up to 90% and 11% of vaginal deliveries, respectively. Despite being widely discussed, childbirth trauma remains unpredictable. This work aims to enhance the modeling of the maternal musculature during childbirth, with a particular focus on understanding the mechanisms underlying the often overlooked perineal injuries.

METHODS

A geometrical model of the pelvic floor muscles (PFM) and perineum (including the perineal body, ischiocavernosus, bulbospongiosus, superficial and deep transverse perineal muscles) was created. The muscles were characterized by a transversely isotropic visco-hyperelastic constitutive model. Two simulations of vaginal delivery were conducted with the fetus in the vertex presentation and occipito-anterior position, with and without the perineum.

RESULTS

The simulation that considered the perineum exhibited higher stresses over an extended area of the PFM, which suggests that including additional structures can impact the obtained results. The maximum stretch of the urogenital hiatus was 2.94 and the maximum stress was 23.86 kPa. The perineal body reached a maximum stretch of 1.95, which was more pronounced near the urogenital hiatus, where perineal tears may occur. The external anal sphincter's transverse diameter decreased by 51% and the maximum principal stresses were observed in the area close to the perineal body, where OASIS can occur.

CONCLUSIONS

The present study emphasizes the importance of including most structures involved in vaginal delivery in its biomechanical analysis and represents another step further in the understanding of perineal injuries and OASIS. The superior region of the perineal body and its connection to the urogenital hiatus and anal sphincter have been identified as the most critical regions, highly susceptible to injury.

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.

Diagnosis and Treatment of Obstetric Anal Sphincter Injuries: New Evidence and Perspectives

Perineal injury during childbirth is a common event with important morbidity associated in particular with third-and-fourth degree perineal tears (also referred to as obstetric anal sphincter injuries—OASIS). Early diagnosis of these damages is mandatory to define a prompt therapeutic strategy and thus avoid the development of late-onset consequences, such as faecal incontinence. For this purpose, various diagnostic exams can be performed after a thorough clinical examination. The management of OASIS includes several measures and should be individualized according to the timing and features of the clinical presentation.

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.

Anal Sphincter Anatomy Prepregnancy to Postdelivery Among the Same Primiparous Women on Dynamic Magnetic Resonance Imaging

OBJECTIVES

The authors used 2-dimensional images from pelvic 3 T magnetic resonance imaging (MRI) to characterize changes in the internal anal sphincter (IAS) and external anal sphincter (EAS) from prepregnancy to postdelivery in the same cohort.

METHODS

This secondary analysis studied a prospective cohort of women undergoing 3 T MRI before their first pregnancy and 6 or more months after delivery. Radial thickness was measured at 12, 3, 9, and 6 o'clock from axial proximal and mid views and oblique distal views of the IAS, and at 3 and 9 o'clock from oblique views of the EAS. Measurements were compared prepregnancy to postdelivery; 10 women had 80% power (α = 0.05) to detect a 0.85-mm change.

RESULTS

Nineteen women completed initial 3 T MRI, 15 achieved pregnancy and birth, and 10 completed postdelivery MRI (4 vaginal birth and 6 Cesarean delivery). Mean change in measurement from prepregnancy to postdelivery was -0.01 mm ± 1.03 mm for the distal 12 o'clock IAS (P = 0.98) and +0.19 ± 0.64 mm for the lateral EAS (P = 0.32). All prepregnancy and postdelivery women had discontinuous EA sphincters at 6 and 12 o'clock. There were no statistically significant changes from prepregnancy to postdelivery in any IAS or EAS location (all >0.05) for the entire cohort, those with vaginal birth, or after Cesarean.

CONCLUSIONS

Anal sphincter measurements on MRI did not change significantly in nulliparous women prepregnancy to postdelivery at any location, and the EAS was not measurable at 12 o'clock in any women at either time point, challenging classic concepts of EAS anatomy.

EFSUMB Recommendations for Gastrointestinal Ultrasound Part 3: Endorectal, Endoanal and Perineal Ultrasound

This article represents part 3 of the EFSUMB Recommendations and Guidelines for Gastrointestinal Ultrasound (GIUS). It provides an overview of the examination techniques recommended by experts in the field of endorectal/endoanal ultrasound (ERUS/EAUS), as well as perineal ultrasound (PNUS). The most important indications are rectal tumors and inflammatory diseases like fistula and abscesses in patients with or without inflammatory bowel disease (IBD). PNUS sometimes is more flexible and convenient compared to ERUS. However, the technique of ERUS is quite well established, especially for the staging of rectal cancer. EAUS also gained ground in the evaluation of perianal diseases like fistulas, abscesses and incontinence. For the staging of perirectal tumors, the use of PNUS in addition to conventional ERUS could be recommended. For the staging of anal carcinomas, PNUS can be a good option because of the higher resolution. Both ERUS and PNUS are considered excellent guidance methods for invasive interventions, such as the drainage of fluids or targeted biopsy of tissue lesions. For abscess detection and evaluation, contrast-enhanced ultrasound (CEUS) also helps in therapy planning.

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.

Three-dimensional/four-dimensional transperineal ultrasound: clinical utility and future prospects

During the last decade, there has been a huge advancement in the use of transperineal ultrasound (TPU) in the field of obstetrics and gynecology. Its main applications in obstetrics include the monitoring of fetal progression in labor and recently the assessment of maternal pelvic dimensions, whereas in gynecology, TPU is at present widely used for the evaluation of the female pelvic floor, opening new boundaries for the assessment of pelvic floor disorders. The association of volumetric three-dimensional techniques has largely contributed to the remarkable progress that has occurred in the use of TPU. The aim of this paper is to offer an overview of the advantages, challenges and future perspectives of the use of TPU for women’s imaging.

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.

Perineal body anatomy seen by three-dimensional endovaginal ultrasound of asymptomatic nulliparae

AIM

The perineal body (PB) plays an important role in supporting the pelvic floor and the posterior vaginal wall, but its attachments and relationships are still debated. This study aimed to assess the normal anatomy of the PB using high-resolution three-dimensional endovaginal ultrasound (3D-EVUS) in asymptomatic nulliparae.

METHOD

To validate the identification of perineal structures, 3D-EVUS was initially performed on nulliparous cadavers. Fresh frozen pelves were prepared and echogenic structures thought to be the PB, the external anal sphincter, the superficial and deep transverse perineii, pubovaginalis, puboperinealis, puboanalis, puborectalis and iliococcygeus muscles were tagged with biopsy needles, and marked with indigo carmine dye for localization during dissection. In the second part of the study, consecutive asymptomatic nulliparae were prospectively imaged with the same ultrasound modality. Interrater reproducibility was assessed off-line from stored 3D US volumes using a standardized technique.

RESULTS

Five fresh frozen pelves and 44 asymptomatic nulliparae were assessed with 3D-EVUS. The PB was seen as an ovoid structure of mixed echogenicity between the rectum and vagina. It appeared to be divided into a superficial level, in contact with the external anal sphincter, the bulbospongiousus and the superficial transverse perineii muscle and a deep level, in contact with puboperinealis and puboanalis muscles. Interobserver repeatability was excellent for the measurements of PB height [intraclass correlation coefficient (ICC) 0.927], PB depth (ICC 0.969) and PB width (ICC 0.932).

CONCLUSION

The PB is divided into two levels with different anatomical relationships with the pelvic floor muscles. 3D-EVUS yields reproducible assessment of this complex structure.

[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.

Transperineal sonographic anal sphincter complex evaluation in chronic anal fissures

OBJECTIVES

The purpose of this study was to assess the role of transperineal sonography in assessment of pathologic changes to the anal sphincter complex in patients with chronic anal fissures.

METHODS

We conducted a prospective case-control study of 100 consecutive patients of any age and both sexes with chronic anal fissures who presented to a colorectal clinic between January 2012 and August 2013 (group A) and 50 healthy volunteers (group B).

RESULTS

The most common patterns of radiologic changes to anal sphincters associated with chronic anal fissures were circumferential thickening of the anal sphincter complex in 5 patients (5%), circumferential thickening of the internal anal sphincter in 3 patients (3%), preferential thickening of the internal anal sphincter at the 6-o'clock position in 80 patients (80%) and the 12-o'clock position in 7 patients (7%), preferential thickening of the internal and external anal sphincters in 3 patients (3%), and thinning of the internal anal sphincter in 2 patients (2%).

CONCLUSIONS

Chronic anal fissures cause differential thickening of both internal and external anal sphincters, with a trend toward increased thickness in relation to the site of the fissure. Routine preoperative transperineal sonography for patients with chronic anal fissures is recommended, and it is mandatory in high-risk patients.

Anal sphincter complex: 2D and 3D endoanal and translabial ultrasound measurement variation in normal postpartum measurements

INTRODUCTION AND HYPOTHESIS

Women may experience anal sphincter anatomy changes after vaginal birth (VB) or Cesarean delivery (CD). Therefore, accurate and acceptable imaging options to evaluate the anal sphincter complex (ASC) are needed. ASC measurements may differ between translabial (TLUS) and endoanal (EAUS) ultrasound imaging and between 2D and 3D US. The objective of this analysis was to describe measurement variation between these modalities.

METHODS

Primiparous women underwent 2D and 3D TLUS imaging of the ASC 6 months after VB or CD. A subset of women also underwent EAUS measurements. Measurements included internal anal sphincter (IAS) thickness at proximal, mid, and distal levels and the external anal sphincter (EAS) at 3, 6, 9, and 12 o'clock positions, as well as bilateral thickness of the pubovisceralis muscle (PVM).

RESULTS

There were 433 women presenting for US: 423 had TLUS and 64 had both TLUS and EAUS of the ASC. All IAS measurements were significantly thicker on TLUS than EAUS (all p < 0.01), while EAS measurements were significantly thicker on EAUS (p < 0.01). PVM measurements with 3D or 2D imaging were similar (p > 0.20). On both TLUS and EAUS, there were multiple sites where significant asymmetry existed in left versus right measurements.

CONCLUSIONS

US modality used to image the ASC introduces small but significant changes in measurements, and the direction of the bias depends on the muscle and location being imaged.

Live anatomy of the perineal body in patients with third-degree rectocele

AIM

In many pelvic floor disorders, the perineal body is damaged or destroyed. There is still a considerable variation in anatomical descriptions of the perineal body and even more debate with regard to its attachments and relationships. Cadaveric dissections do not always reflect the functional behaviour of structures in the pelvis and description of live anatomy on imaging studies is not always reliable. This study aimed to define the anatomy of the perineal body in patients with rectocele during the live dissection required for minimally invasive surgical repair.

METHOD

From January 2007 to December 2009 consecutive patients requiring surgery for third-degree rectocele and symptoms of obstructed defaecation were recruited. Participants underwent dissection of the perineal body, rectum and vagina preliminary to a tissue fixation system, an operation which inserts a tensioned tape to repair the perineal body.

RESULTS

Thirty Caucasian female patients, mean age 61 (range 47-87) years, mean parity 2.6 (range 1-5), were included. Live dissection demonstrated that the perineal body was divided into two parts, joined by a stretched central part, anchored laterally by the deep transverse perineii muscle to the descending ramus of the pubic bone. The mean longitudinal length of the perineal body was 4.5 (3.5-5.5) cm, accounting for 50% of the posterior vaginal support.

CONCLUSION

In women with low rectocele, the perineal body appears to be divided into two parts, severely displaced behind the ischial tuberosities.

Postpartum translabial 2D and 3D ultrasound measurements of the anal sphincter complex in primiparous women delivering by vaginal birth versus Cesarean delivery

INTRODUCTION AND HYPOTHESIS

Consensus on normal translabial ultrasound (TL-US) anal sphincter complex measurements for postpartum women is lacking. We aimed to evaluate normative measurements in 2D and 3D TL-US for the anal sphincter complex (ASC) at 6 months postpartum and compare these measurements in women who had a vaginal birth (VB) and in those who had a Cesarean delivery (CD).

METHODS

A large, prospective cohort of primiparous women underwent 2D and 3D TL-US 6 months after their first delivery. For normative sphincter measurements, we excluded women with third- or fourth-degree lacerations or with sphincter interruption on TL-US. Measurements included the sphincter thickness at the 3, 6, 9, and 12 o'clock positions of the external anal sphincter (EAS) and the internal anal sphincter (IAS) at proximal, mid, and distal levels. We also measured the mean coronal diameter of the pubovisceralis muscle (PVM).

RESULTS

696 women consented to participate, and 433 women presented for ultrasound imaging 6 months later. Women who sustained a third- or fourth-degree laceration had significantly thicker EAS measurements at 12 o'clock. Sphincter asymmetry was common (69 %), but was not related to mode of delivery. Only IAS measurements at the proximal and distal 12 o'clock position were significantly thicker for CD patients. There were no significant differences in the EAS or PVM measurements between VB and CD women.

CONCLUSIONS

There appear to be few differences in normative sphincter ultrasound measurements between primiparous patients who had VB or CD.

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.

State of the art: an integrated approach to pelvic floor ultrasonography

Surgical management of pelvic floor disorders depends on a comprehensive understanding of the structural integrity and function of the pelvic floor. For visualizing this region, ultrasonography has emerged as a procedure that is relatively easy to perform, cost-effective and widely available. In this review, pelvic floor ultrasonography, including two-dimensional (2D), three-dimensional (3D) and 4D imaging as well as transvaginal, endoanal and transperineal techniques, is discussed from a global and multicompartmental perspective, rather than using a compartmentalized approach. The role of the different sonographic modalities in the major disorders of the pelvic floor-urinary and fecal incontinence, pelvic organ prolapse and obstructed defecation syndrome-is evaluated critically.

Anatomic characteristics of anal fistula on three-dimensional anorectal ultrasonography

BACKGROUND

Surgery for anal fistula is often associated with continence disorders due to the transection of sphincter muscles. Extensive knowledge of anal canal anatomy and anal fistula can help prevent this outcome.

OBJECTIVE

This study aimed to correlate the anatomical conformation of the anal canal, the fistula track, and the internal opening according to sex and hemicircumference (anterior vs posterior) by use of 3-dimensional ultrasonography.

METHODS

One hundred sixty-five patients with fistula were evaluated with 3-dimensional ultrasound and grouped according to sex, fistula type, internal opening, and track position. Fistulas were transsphincteric in 128 subjects and intersphincteric in 37 subjects. The study measured the external and internal anal sphincter, the puborectalis, the distance from the internal opening to the distal edge of the external and internal sphincter, the length of the internal and external sphincter compromised by the track, and the percentage of compromised muscle.

RESULTS

The anal canal muscles were longer in males. The distance from the internal opening to the internal sphincter was greater for the posterior hemicircumference. The point where the fistulous track crossed the anterior external sphincter was similar for the 2 sexes, but the percentage of compromised muscle was greater in females. The point where the fistulous track crossed the internal sphincter was similar for the 2 sexes, but the percentage of compromised internal sphincter was greater in males for the posterior hemicircumference. The study was limited by the absence of testing for interobserver and intraobserver agreement.

CONCLUSION

The anal canal muscles are longer in males and the pectinate line is asymmetrical. In females, the percentage of compromised external sphincter was greater in the anterior hemicircumference because of the shorter external sphincter, whereas in males the percentage of compromised internal sphincter was greater in the posterior hemicircumference.

Correlation between gross anatomical topography, sectional sheet plastination, microscopic anatomy and endoanal sonography of the anal sphincter complex in human males

This study elucidates the structure of the anal sphincter complex (ASC) and correlates the individual layers, namely the external anal sphincter (EAS), conjoint longitudinal muscle (CLM) and internal anal sphincter (IAS), with their ultrasonographic images. Eighteen male cadavers, with an average age of 72 years (range 62-82 years), were used in this study. Multiple methods were used including gross dissection, coronal and axial sheet plastination, different histological staining techniques and endoanal sonography. The EAS was a continuous layer but with different relations, an upper part (corresponding to the deep and superficial parts in the traditional description) and a lower (subcutaneous) part that was located distal to the IAS, and was the only muscle encircling the anal orifice below the IAS. The CLM was a fibro-fatty-muscular layer occupying the intersphincteric space and was continuous superiorly with the longitudinal muscle layer of the rectum. In its middle and lower parts it consisted of collagen and elastic fibres with fatty tissue filling the spaces between the fibrous septa. The IAS was a markedly thickened extension of the terminal circular smooth muscle layer of the rectum and it terminated proximal to the lower part of the EAS. On endoanal sonography, the EAS appeared as an irregular hyperechoic band; CLM was poorly represented by a thin irregular hyperechoic line and IAS was represented by a hypoechoic band. Data on the measurements of the thickness of the ASC layers are presented and vary between dissection and sonographic imaging. The layers of the ASC were precisely identified in situ, in sections, in isolated dissected specimens and the same structures were correlated with their sonographic appearance. The results of the measurements of ASC components in this study on male cadavers were variable, suggesting that these should be used with caution in diagnostic and management settings.

3D Ultrasound in Gynecology and Reproductive Medicine

With advances occurring in medicine on a daily basis, it was only a matter of time before essential gynecological investigations, such as ultrasound, were modified. Many clinicians remain unconvinced by its reputed advantages and 3D ultrasound is not without disadvantages. These mainly relate to the cost implications and training requirements. 3D ultrasound imaging is still at a relatively early stage in terms of its role as a day-to-day imaging modality in gynecology and reproductive medicine. 3D imaging has several obvious benefits that relate to an improved spatial orientation and the demonstration of multiplanar views, of which the coronal plane is particularly useful. It offers a more objective and reproducible measurement of volume and vascularity of the region of interest, and an improved assessment of normal and pathological pelvic organs through further postprocessing modalities, including tomographic ultrasound imaging and various rendering modalities. It also has the benefit of offering reduced scanning time, the option of teleconsultation and storage of images for re-evaluation. However, other than its application in the assessment and differentiation of uterine anomalies, there is very little evidence demonstrating that 3D ultrasound results in a clinically relevant benefit or negates the need for further investigation. Future work should ensure that 3D ultrasound is compared with conventional imaging in randomized trials where the observer is blind to the outcome, only after which will we truly be able to evaluate its role in an evidence-based manner.

Endoanal ultrasound in benign anorectal disorders: clinical relevance and possibilities

Endoanal ultrasound is a well-established technique used to evaluate benign anorectal disorders. The technique is easy to perform, has a short learning curve and causes very little discomfort. Reconstruction of 3D images is possible. The clinical indications for endoanal ultrasound in benign anorectal diseases are fecal incontinence and peri-anal fistula. Sphincter defects can be depicted with precision and correlate perfectly with surgical findings. Furthermore, an impression of sphincter atrophy can be established. With perianal fistula the tracts can be visualized. Introducing hydrogen peroxide via the external fistula opening improves imaging. Endoanal ultrasound and MRI have comparable results in diagnosing anorectal disorders.