Multiplanar anal endosonography--normal anal canal anatomy

Anatomical characteristics of anal fistula evaluated by three-dimensional anorectal ultrasonography: is there a correlation with Goodsall's theory?

Purpose We aimed to correlate the course of the anal fistula tract (T), location of the external opening (EO) and internal opening (IO) in anterior (A) and posterior (P) circumference using 3D-US according to Goodsall's rule.

Methods 151 patients with primary cryptoglandular Transsphincteric fistulas were examined with 3D-US and compared with surgical finding. The type of the T (straight or curved), EO and IO were identified and divided into 3 Groups: GI: EO and IO are located in a position; GII: EO and IO are located in P position and GIII: OE and OI are located in the opposite position. The findings were correlated with Goodsall's rule.

Results 74/151(49%) were included in GI, of them, 41 (55%) were male (33/44% had straight tract and 8/11% curved) and 33 (45%) female (15/20%-straight and 18/25%-curved). GII included 68 (45%), of them, 50 (74%) were male (39/57%-straight and 11/15%-curved) and 18 (26%) female (14/20%-straight and 04/8%-curved). GIII = 9 (6%) and all of them had curved tract. The overall concordance between 3D-US and surgical finding was 98% for tract and 96% for IO.

Conclusion The 3D-US findings correlate with the Goodsall's rule in transsphincteric fistulas located in the anterior circumference straight type, in male, while in females the distribution of curved and straight paths is similar. In the posterior circumference no correlation was observed in both the sexes.

Pubovisceral muscle and anal sphincter defects in women with fecal or urinary incontinence after vaginal delivery

BACKGROUND

Vaginal delivery is the most frequent cause of direct anal sphincter trauma as well as pelvic floor muscle defects in women with corresponding signs and symptoms. The aim of the present study was to identify anatomical and functional abnormalities of the anal canal and pelvic floor in women who had had a vaginal delivery and determine the relationship between such abnormalities and the symptoms and severity of fecal incontinence (FI).

METHODS

Consecutive female patients with symptoms of fecal and/or urinary incontinence were recruited through the colorectal and gynecological outpatient clinics at two large university hospitals and were eligible if they had had at a vaginal delivery. All women were assessed for symptoms FI by means of the Cleveland Clinic Florida Incontinence Scale (CCFIS) and for urinary incontinence symptoms, including the presence of complaints of any involuntary leakage of urine, leakage on exertion, sneezing, or coughing, and/or leaking or losing urine associated with an urge to urinate. All women underwent anorectal and endovaginal three-dimensional ultrasonography and anal manometry. The extent of the anal sphincter and PVM defects identified by ultrasound was scored from 1 to 6 based on the longitudinal involvement of the external and internal anal sphincter, the radial angle of the anterior external anal sphincter defect and the longitudinal involvement of the PVM.

RESULTS

There were 130 women and 89 (68%) had at least one defect of the anal sphincter or the pubovisceral muscle or both (42/32% had a pubovisceral muscle defect with or without sphincter defects, 47/36% women had an intact pubovisceral muscle but sphincter defect); and 41 (32%) had intact anal sphincter and pubovisceral muscles. The mean levator hiatus area at rest in women with anal sphincter and/or pubovisceral muscle defects was 18 (± 4 SD) which was significantly greater than in women with no defects (16 ± 3 SD; p = 0.01). Women with PVM defects had significantly higher ultrasound scores (median ultrasound score = 4/range 1-10 vs Intact = 2/range 2-5), indicating more extensive defects (p = 0.001). Bivariate analysis revealed a positive association (p < 0.05) between increasing FI symptom severity (CCFIS score) and women with PVM defects (ρ = 0.6913). Within the group of women with defects mean maximum anal squeeze pressure was significantly lower in women with PVM defect (mean 73 ± 34 SD mmHg vs mean 93 ± 38 SD; p = 0.04). Women with PVM defects had significantly higher median CCFIS scores (median score, 7/range 0-16) compared to women with intact PVM (4/range 0-10) (p < 0.001). There was a significant positive correlation between the CCFIS and ultrasound scores (ρ = 0.625; p < 0.001). Bivariate analysis revealed a negative correlations between the CCFIS score and the lengths of the anterior EAS (ρ = - 0.5621, p < 0.001), IAS (ρ = - 0.40, p < 0.001) and the area of the levator hiatus (ρ = 0.5211, p = 0.001). However, no significant correlations were observed between CCFIS scores and the gap measurement (ρ = 0.101; p = 0.253) or the resting (ρ = - 0.08, p = 0.54) or squeeze pressure (ρ = - 0.12; p = 0.34) values on anal manometry. The variables associated with worsening FI symptom severity (CCFIS score) that remained significant in multiple linear regression included the shorter lengths of the anterior EAS and/or the lengths of the anterior IAS and increased area of the levator hiatus.

CONCLUSIONS

The study data demonstrate that half of the women had combined defects of PVM and sphincter. There were correlations between anatomical abnormalities including the anal sphincter and/or pubovisceral muscle defects with decrease in the anal pressures and increased severity of FI.

Synchronized functional anal sphincter assessment: maximizing the potential of anal vector manometry and 3-D anal endosonography

BACKGROUND

Understanding the association between structure and function is vital before considering surgery involving anal sphincter division. By correlating three-dimensional anal endosonography (AES) and three-dimensional anal canal vector volume manometry (VVM), this study details a method to produce measurements of both sphincter length and pressure leading to identification of the functionally important areas of the anal canal. The aim of this study was to provide combined detailed information on anal canal anatomy and physiology.

METHODS

Twelve males and 12 nulliparous females with no bowel symptoms underwent VVM (using a water-perfused, eight-channel radially arranged catheter) and AES.

KEY RESULTS

The synchronization of AES and VVM identified that the majority of rest and squeeze anal pressure is present in the portion of the anal canal covered by both anal sphincters. Nearly, 20% of overall resting anal pressure is produced distal to the caudal termination of the internal anal sphincter. Puborectalis accounts for a significantly greater percentage volume of pressure in females both at rest and when squeezing, though the total volume of pressure is not significantly greater.

CONCLUSIONS AND INFERENCES

The majority of resting and squeezing pressure and the least asymmetry, in both sexes, is in the portion of the anal canal covered by external anal sphincter. In females, the external anal sphincter is shorter and a proportionately longer puborectalis accounts for a greater percentage of pressure. Sphincter targeted fistula surgery in females must be performed with special caution. A protective role for puborectalis following obstetric anal sphincter injury is suggested.

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.

Three-dimensional endoanal ultrasonography in daily proctological practice

Three-dimensional endoanal ultrasonography (3D-EAUS) provides unequalled quality in terms of the anatomical image of the anal canal and sphincter complex. In less than one minute it produces a three-dimensional "cube" that can be manipulated in all spatial dimensions, then archived. In just a few years it has become a new gold standard exploration in proctology. In addition to image quality, 3D-EAUS has the advantage of being easily and rapidly performed, well-tolerated and moderate in cost. For anal incontinence, 3D-EAUS contributes to the identification of sphincter defects. The anatomy of the sphincters can be evaluated spatially. Simple scoring systems with good reproducibility and readily applicable in routine practice can be used to evaluate the "damaged" sphincter volume. For the management of anoperineal suppurations, 3D-EAUS provides information on the fistulous track(s) and on potential collections. These data are crucial as the choice of treatment and its efficacy depend on accurate topographic assessment of the suppuration and the state of the sphincter apparatus.

The role of 3-dimensional anorectal ultrasonography in the assessment of anterior transsphincteric fistula

PURPOSE

The aim of this study was to evaluate the role of 3-dimensional anorectal ultrasonography in the choice of surgical technique according to the position of the fistulous tract in patients with anterior transsphincteric anal fistula.

METHODS

A total of 33 patients (18 male) with anterior transsphincteric fistulas were evaluated by ultrasonography. The length of the external and internal anal sphincters, the position of the internal opening, the length of the compromised sphincter, and the percentage of sphincter muscle to be transected during surgery were measured, compared between sexes, and used in planning the surgery. Postoperative incontinence symptoms were quantified with a Wexner score.

RESULTS

The external and internal sphincters were longer and the position of the internal opening was higher in males. The position where the tract crossed the external sphincter was in both sexes, but the percentage of compromised muscle was higher in females because of the smaller length of the external sphincter. Seton placement followed by fistulotomy or advanced flap repair were indicated in 11 of 18 males and 13 of 15 females as the tract crossed the external sphincter above 50.0%. The mean postoperative follow-up was 12 months. Overall, minor fecal incontinence symptoms were identified in 16 (48.0%) patients. Of these, 11 (73.0%) females and 5 (28.0%) males had a mean incontinence score of 2.9 and 3.0, respectively.

CONCLUSIONS

Three-dimensional ultrasonography was shown to be useful in the preoperative assessment of anterior transsphincteric fistulas by quantifying the length of muscle to be transected, contributing to the choice of a safe treatment approach and to the reduction of the rate of postoperative continence disorders.

Choice of endosonographic equipment and normal endosonographic anatomy

Endosonography may be considered as a very special area in endoscopy. It really revolutionised endoscopy in allowing seeing behind the digestive lumen, in accessing the mediastinum and the pancreas, and in performing the first "NOTES" procedures. Endoscopists have usually mixed feelings towards endosonography: most of them consider EUS as the "Holy Grail" since it is one of the most complex diagnostic and therapeutic endoscopic procedures, but many users are still uncomfortable with some anatomical landmarks and with the choice of equipment. Echoendoscopes are indeed known to be costly and fragile, and quite versatile with the choice between different manufacturers, and between radial or linear (convex array) oriented instruments. This review aims at providing up-to-date information on the different types of echoendoscopes and processors and on normal endosonographic anatomy of the digestive tract, the mediastinum, the pancreas and the biliary tree.

Three-dimensional endoanal ultrasonography: intraobserver and interobserver agreement using scoring systems for classification of anal sphincter defects

OBJECTIVES

To determine the degree of intraobserver and interobserver agreement for an experienced and an inexperienced sonologist using two scoring systems for ultrasonographic assessment of anal sphincter defects.

METHODS

The study sample comprised the datasets of all women aged between 20 and 40 years who had attended our outpatient clinic and undergone a complete three-dimensional (3D) endoanal ultrasound (EAUS) examination in the period from January 2003 to December 2005. The EAUS datasets were assessed twice independently by two sonologists: one with experience of > 400 3D EAUS assessments and one inexperienced sonologist who had performed approximately 50 assessments before the study. Cases with intraobserver disagreement were resolved by a third (final) assessment. The final assessment from each observer was used to determine the degree of interobserver agreement. Sphincter defects were classified according to our EAUS defect score and the Starck score.

RESULTS

EAUS datasets of 55 women were included. Based on first vs. second assessments, intraobserver agreement for the experienced sonologist was good for our EAUS defect score (weighted kappa, 0.75) and the Starck score (weighted kappa, 0.73). Intraobserver agreement for the inexperienced sonologist was moderate for our EAUS defect score (weighted kappa, 0.58) and good for the Starck score (weighted kappa, 0.62). Interobserver agreement was good for both our EAUS defect score (weighted kappa, 0.65) and the Starck score (weighted kappa, 0.74).

CONCLUSIONS

Intraobserver and interobserver agreement was acceptable for both scoring systems. The experienced sonologist obtained a higher degree of intraobserver agreement than did the inexperienced sonologist.

The long-term efficacy of fissurectomy and botulinum toxin injection for chronic anal fissure in females

INTRODUCTION

Healing rates for botulinum toxin injection for anal fissure may be improved if combined with fissurectomy. This procedure has a decreased risk of incontinence, which is particularly important in females. We investigated the long-term efficacy of fissurectomy and botulinum toxin injection for chronic resistant fissures in females.

METHODS

Female patients who consented underwent excision of the fissure edges and injection of 25-100 units of botulinum into the intersphincteric space. Patients were followed up 2 months after the procedure and over a period of up to 39 months.

RESULTS

Forty-six patients (mean age, 42 years) were recruited. No patient had incontinence symptoms preoperatively. At a median follow-up period of 11 months, there was a cure rate of 85 percent in 44 patients. After a median follow-up of 22 months, 12 more patients were lost to follow-up. Of the remaining patients, 16 (50 percent) suffered recurrence during the follow-up period. Five patients required further surgical intervention. Three patients suffered chronic perianal infection requiring antibiotic treatment or surgery. There was one case of incontinence at final assessment: the patient complained of urge incontinence, which has persisted for more than 18 months.

CONCLUSIONS

Fissurectomy and botulinum toxin injection for the treatment of chronic anal fissure in females seems to be effective in the medium-term but there is a high rate of late recurrence. However, only a minority of patients proceed to more invasive surgical intervention, which may make it a useful option in patients not suitable for lateral sphincterotomy.

Anal canal anatomy showed by three-dimensional anorectal ultrasonography

BACKGROUND

Demonstrate precisely the anatomic configuration of the anal canal and the length and thickness of the anal sphincters using three-dimensional (3-D) anorectal ultra-sonography in both genders.

METHODS

Twelve normal volunteer males and 14 females, with a mean age of 52.4 and 50.3 years, respectively, were prospectively enrolled in this study. All individuals from both groups were submitted to anorectal ultra-sonography. The anal canal was analyzed, measuring the length and thickness of the external anal sphincter (EAE), internal anal sphincter (IAS), puborectalis muscle (PR) and the gap (distance from the anterior EAS to the anorectal junction) in the midline longitudinal (ML) and transverse (MT) planes, and the results were compared between quadrants and genders.

RESULTS

The distribution of sphincter muscles is asymmetric in both genders. The anterior upper anal canal is an extension of the rectal wall with all layers clearly identified. The anterior IAS is formed in the distal upper anal canal and is significantly shorter in female than in male in all quadrants. The anterior IAS length is shorter than the posterior and lateral in both genders. The anterior EAS length is significantly shorter (2.2 cm) and the gap is longer (1.2 cm) in female than in male (3.4 cm) (0.7 cm) (p < 0.05), respectively. The posterior and lateral EAS-PR is significant longer in males (3.6 cm) (3.9 cm) than in females (3.2 cm) (3.5 cm) (p < 0.05), respectively. The lateral EAS-PR is significant longer than the posterior part in both genders. The anterior IAS is significantly thicker in males (0.19 cm) than in females (0.12 cm) (p = 0.04).

CONCLUSION

3-D anal endosonography enabled measurement of the different anatomical structures of the anal canal and demonstrated its asymmetrical configuration. The shorter anterior EAS and IAS associated with a longer gap could justify the higher incidence of pelvic floor dysfunction in females, especially fecal incontinence and anorectocele with rectal intussusception.

A method of dissecting the pelvic floor to allow anatomical validation of images of the soft tissues

A method of intact postmortem removal of the pelvic floor for imaging correlation studies, with minimal access disfigurement, is described. This consists of subcutaneous removal of both ischiopubic rami with division of the obturator membrane cranial to the origin of the levator ani muscles. The anatomical relationships of soft tissue surrounding the distal birth canal are thus preserved. The report discusses the need for, constraints on, and limitations of such studies in the unique problems of determining the dynamic anatomical configuration of the soft tissues of the pelvic floor. It illustrates the clinical relevance of initial studies, and reviews the background contributions of members of the group.

Computer-assisted evaluation of perianal fistula activity by means of anal ultrasound in patients with Crohn's disease

OBJECTIVES

Assessment of the activity of perianal fistulas may be of clinical relevance in patients with Crohn's disease. Fistula activity is currently evaluated by means of magnetic resonance imaging; anal ultrasound can also be used, but its diagnostic performance in this setting remains to be defined. Our aims were to evaluate the agreement between clinical examination, magnetic resonance imaging, and anal ultrasound in assessing perianal fistula activity, and to apply computerized analysis to improve the assessment of ultrasound images.

METHODS

Thirty-one consecutive patients with Crohn's perianal fistulas underwent clinical examination, and magnetic resonance and anal ultrasound imaging. Active fistulas were defined as the presence of active drainage or signs of local inflammation on clinical examination, and the definition was confirmed by surgical examination. Activity was assessed on the basis of T2 hyperintensity on magnetic resonance imaging and the degree of hypoechogenicity on anal ultrasound; the anal ultrasound images were also analyzed using dedicated computer image-analysis software.

RESULTS

Twenty-five patients had an active fistula at clinical examination. The agreement between clinical examination and magnetic resonance imaging was good (k-value = 0.739), whereas that with anal ultrasound was only fair (k-value = 0.266-0.294); computer-assisted analysis of the anal ultrasound images improved the agreement from fair to good (k-value = 0.608-0.670).

CONCLUSIONS

Anal ultrasound can be used to assess fistula track activity in patients with Crohn's disease. The diagnostic performance of the technique can be improved to values comparable with those of magnetic resonance imaging by using a computer-assisted evaluation of the anal ultrasound images.

The current role of imaging techniques in faecal incontinence

Faecal incontinence is a common multifactorial disorder. Major causes of faecal incontinence are related to vaginal delivery and prior anorectal surgery. In addition to medical history and physical examination, several anorectal functional tests and imaging techniques can be used to assess the underlying pathophysiology and to guide treatment planning in faecal incontinent patients. Anorectal functional tests provide functional information, but the potential strength comes from combining test results. Imaging techniques, including defecography, endoanal sonography, and magnetic resonance (MR) imaging, provide structural information about the anorectal region with a direct clinical impact. The major role of imaging techniques in faecal incontinence is visualising the structural and functional integrity of the anal sphincter complex. Both two-dimensional endoanal sonography and endoanal MR imaging are accurate tools to depict anal sphincter defects. The major advantage of endoanal MR imaging is the accurate demonstration of external anal sphincter atrophy. Recent studies have suggested that external phased array MR imaging and three-dimensional endoanal sonography are also valuable tools in the diagnostic work up of faecal incontinence. Decisions about the preferred technique will mainly be determined by availability and local expertise. This article demonstrates the current role of tests, predominantly imaging tests, in the diagnostic work up of faecal incontinence.

The external anal sphincter and the role of surface electromyography

Assessment of the neuronal control of the external anal sphincter (EAS) has long been restricted to investigating patients with defecation disorders by invasive tools such as needle electromyography (EMG), while less invasive techniques have been regarded as non-suitable for diagnostic purposes. Multichannel surface EMG by means of electrode arrays applied to anal sphincter muscle records and identifies individual motor unit action potentials, their place of origin along the circumference, their repetitive firing frequency, and their progression along the muscle fibres at different levels within the anal canal. These data shed doubts on conventional knowledge about the anatomy of the EAS muscle, and confirms new concepts of anatomical differences between gender. This may eventually be transferred to a new understanding of the role of symmetry and asymmetry of pelvic floor innervation and its role in the pathogenesis of fecal incontinence.

Endosonography of the anal sphincter in women of different ages and parity

OBJECTIVES

To obtain reference data representative of normal findings at anal endosonography in pregnant and non-pregnant women. To determine intraobserver and interobserver agreement in the detection of endosonographic anal sphincter defects in asymptomatic women.

METHODS

Twenty-five non-pregnant nulliparous women and 25 non-pregnant parous women (age range, 20-67 years) and 47 pregnant women (age range, 21-39 years) underwent anal manometry and anal endosonography. The endosonographic internal and external sphincter thickness and sphincter length were measured online. Endosonographic sphincter defects were measured and classified offline from videotapes by two independent examiners using an endosonographic defect score ranging from 0 (no defect) to 16 (maximal defect), the score taking into account the location and the longitudinal and circumferential extension of the defect.

RESULTS

Endosonographic sphincter thickness and length did not differ between non-pregnant nulliparous and parous women and did not change substantially with age. The anal sphincter was thicker and the anal resting pressure area and manometric sphincter length were greater in pregnant than in non-pregnant women of the same age (20-39 years). There was good intra- and interobserver agreement with regard to detection of endosonographic anal sphincter defects (kappa > or = 0.70). Eighteen (19%) women had endosonographic sphincter defects but in only four (4%; 4/97) cases were they moderate or large (defect score, 7-10). Ten (20%) of the non-pregnant women reported minor gas incontinence and one reported minor incontinence for both gas and liquid stool. The frequency of incontinence did not differ between women with and without sphincter defects.

CONCLUSIONS

Reference data representative of normal findings at anal endosonography have been established for non-pregnant women and for nulliparous women in the third trimester of pregnancy. Small endosonographic sphincter defects and minor gas incontinence are common in women without known sphincter trauma. They seem to be unrelated to each other and may be regarded as normal variants.

Innervation zones of the external anal sphincter in healthy male and female subjects. Preliminary results

OBJECTIVES

The objective of this work was to investigate the distribution of the innervation zones of the motor units that make up the external anal sphincter (EAS) in healthy males and females.

METHODS

A cylindrical probe carrying a circumferential array of 16 electrodes was used to detect the generation, propagation and extinction of individual motor unit action potentials (MUAPs) at 1, 2, and 3 cm depth from the orifice of the anal canal during maximal voluntary contractions of the EAS. Fifteen healthy males and 37 healthy nulliparous females were investigated.

RESULTS

IZs could be detected in all males and in 34 out of 37 females. In the males, the IZs are scattered in the right and left hemisphincter at each of the three levels and their distribution is not affected by depth. In the females, the distribution is also concentrated in the right and left hemisphincter at depth 1 cm but is more uniform at depth 2 cm and more concentrated in the dorsal and ventral regions at depth 3 cm. ANOVA shows a statistically significant dependence of the IZ distribution on depth only in females and not in males.

CONCLUSIONS

It is concluded that (a) IZs of the EAS can indeed be detected with a circumferential array placed at different depths along the anal canal; (b) large individual variability is observed, and (c) IZs show similar distribution at the three depth levels in males and different distributions in females.