Effect of vaginal delivery and ageing on the anatomy of the female anal canal assessed by three-dimensional anorectal ultrasound

Perianal ultrasound (PAUS): visualization of sphincter muscles and comparison with digital-rectal examination (DRE) in females

Background

The aim of this study was to determine the reproducibility and tolerance of perianal ultrasound (PAUS) and detect differences in sphincter muscles between various measuring positions and different maneuvers. PAUS was compared to digital-rectal examination (DRE) to see if sphincter contraction is visible and gradable in ultrasound volumes.

Methods

Fifty women underwent a medical history, DRU and PAUS by two uro-gynecologists in a prospective trial. PAUS volumes were measured via different parameters in different maneuvers. Examiners’ DRE impressions of sphincter tone were scaled with the DRESS-score. All patients completed a questionnaire.

Results

Thirty-five patients with complete PAUS and DRE were included in the study. Fifteen patients were excluded due to poor ultrasound volume quality or sphincter defects. Comparison of sphincter muscle thickness at different positions in PAUS showed significant differences between 6 and 12 o’clock positions (12 > 6 o’clock) and diameters (horizontal > vertical). No difference was found between the examiners. In comparison of rest and contraction only the vertical diameter changed. There was a negative but not significant correlation between PAUS measurements and DRESS-scores. Twenty-six patients completed the questionnaire that revealed women preferred PAUS over DRE.

Conclusion

PAUS is a reproducible and good tool to visualize the anal canal. It is comfortable for patients and easily handled by examiners. Sphincter muscle contraction is iso-volumetric. Vertical diameter changes during contraction leading the anal canal change its shape to oval due to external influence. PAUS is the ideal additional tool to visualize relevant structures that are palpable on DRE.

Clinical, functional and morphologic evaluation of patients undergoing lateral sphincterotomy for chronic anal fissure treatment. Identification of factors that can interfere with fecal continence

Objective Evaluate clinical, functional and morphologic outcomes of lateral sphincterotomy for chronic anal fissure treatment, and correlate the findings with factors that influence in the anal continence.

Method In a prospective study, female patients treated by lateral sphincterotomy for chronic anal fissure were assessed using Wexner's incontinence score and grouped according to score: group I (score = 0) and group 2 (score ≥1) and evaluated with anal manometry and anorectal 3D ultrasonography.

Results Thirty-six womens were included, 33% had vaginal delivery. Seventeen patients were included in group I and 19 in group II. We found no difference in age, parity and mode of delivery between groups. A significant difference with respect to percentage reduction in resting pressures was noted, when comparing group 1 versus group 2. The anal sphincter muscle length was similar in both groups. However, the length and percentage of transected internal anal sphincter was significantly greater in group II.

Conclusion There was a correlation between fecal incontinence symptoms after sphincterotomy with the percentage of resting pressure reduction, length and percentage of transected internal anal sphincter.

Anal Sphincter Length as Determined by 3-Dimensional Endoanal Ultrasound and Anal Manometry: A Study in Healthy Nulliparous Women

OBJECTIVES

The normal female external anal sphincter (EAS) is shorter anteriorly than laterally and posteriorly. Furthermore, the thickness of the very proximal part of the circular EAS is thinner than 50% of the lateral and posterior EAS thickness. The extent of these features is not fully explored. The aim of this prospective study was to assess the normal anal sphincter with 3-dimensional (3D) endoanal ultrasound (EAUS) and to relate 3D EAUS length measurements to sphincter length determined by anal manometry.

METHODS

Healthy premenopausal nulliparous women underwent anal manometry and 3D EAUS examinations. Two experienced colorectal surgeons independently assessed all scans, blinded to any patient data.

RESULTS

A total of 43 women were included. Four scans were incomplete and excluded from the analysis. Interobserver agreement was fair to very good for the various length measurements. The mean length from the distal border of the puborectal muscle to the very proximal border of the anterior EAS (the anterior gap) was 4.4 (95% confidence interval, 3.9-4.9) mm, whereas the length to the level where the anterior EAS thickness was at least 50% of the lateral and posterior EAS thickness was 7.2 (95% confidence interval, 6.5-7.9) mm. Manometric sphincter length at rest did not correlate with any 3D EAUS length measurements.

CONCLUSIONS

In the normal anterior female anal canal, the EAS is not present or appears with less than 50% of the thickness of the lateral and posterior EAS for the first 7.2 mm below the distal border of the puborectal muscle.

A missing distal complex of the external and internal anal sphincters: a macroscopic and histologic study using Japanese and German elderly cadavers

The lower margin of the internal anal sphincter (IAS) is considered to lie on a J-shaped, subcutaneous part (SCP) of the external anal sphincter (EAS). The lower IAS is united with the J-shaped SCP to form a smooth-striated muscle complex. In the first part of this study, we ensured the presence of the J-shaped EAS in the lateral wall of the anal canal from 12 near-term fetuses. Second, in the lateral anal wall, the examination of the longitudinal section from 20 male and 24 female Japanese cadavers (72-95 years-old) demonstrated that the J-shaped EAS was lost in 15 (34%) due to the very small SCP. Third, we demonstrated that the J-shaped EAS was restricted in the latera anal wall using longitudinal histological sections of the anal canal from 11 male Japanese cadavers (75-89 years-old). Therefore, a site-dependent difference in the IAS-EAS configuration was evident. Finally, we compared a frequency of the lost J-shape between human populations using 10 mm-thick frontal slices from 36 Japanese and 28 German cadavers. The two groups of cadavers were compatible in age (a 0.2-years' difference in males). The macroscopic observations revealed that the J-shaped EAS was absent from 13 (36%) Japanese and six (20%) German specimens, suggesting that the SCP degeneration occurred more frequent in elderly Japanese than elderly German individuals (p < 0.05). The distal IAS-EAS complex seemed to push residual feces out of the anal canal at a transient phase from evacuation to closure. The absence might be the first sigh of anal dysfunction.

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.

The evaluation of the effect of vaginal delivery and aging on anal sphincter anatomy and function

OBJECTIVE

This study was conducted to evaluate the effect of vaginal delivery and aging on anal sphincter anatomy and function.

METHOD

Asymptomatic thirty women were included in this prospective study. Group 1 included 10 women (age range: 18-50) who had never been pregnant. Group 2 included 10 women (age range: 18-50) who had vaginal delivery. Group 3 included 10 women over 50 who had vaginal delivery.

RESULTS

There was no statistically significant difference between the three groups in terms of resting and squeeze pressures. It was found that sphincter thickness showed statistically significant difference between the group 1 and group 3, and also group 2 and group 3. There was not statistically significant difference between the group 1 and group 2 in terms of sphincter thickness. There was a positive correlation between the age and sphincter thickness in all groups. In terms of sphincter thickness and pressure findings there was a positive correlation between the squeeze pressure and external anal sphincter thickness only in group 3.

CONCLUSION

The vaginal delivery did not have a negative influence on the structure and function of the anal sphincter in asymptomatic women. However, it was found that anal sphincter thickness changed strongly in a positive manner with aging.

Endoanal ultrasound in perianal fistulae and abscesses

Endoanal ultrasound is a technique that provides imaging of the anal sphincters and its surrounding structures as well as the pelvic floor. However, endoanal magnetic resonance imaging (MRI) is preferred by most physicians, although costs are higher and demand easily outgrows availability. Endoanal ultrasound is an accurate imaging modality delineating anatomy of both cryptoglandular as well as Crohn perianal fistula and abscess. Endoanal ultrasound is comparable with examination under anesthesia and equally sensitive as endoanal MRI in fistula detection. When fistula tracts or abscesses are located above the puborectal muscle, an additional endoanal MRI should be performed. Preoperative imaging is advocated in recurrent cryptoglandular fistula because a more complex pattern can be expected. Endoanal ultrasound can help avoid missing tracts during surgery, lowering the chance for the fistula to persist or recur. It can easily be performed in an outpatient setting and endosonographic skills are quickly incremented. Costs are low and endoanal ultrasound has the potential to improve outcome of patients with both cryptoglandular and fistulizing Crohn disease; therefore, it values more attention.

DO CHANGES IN ANAL SPHINCTER ANATOMY CORRELATE WITH ANAL FUNCTION IN WOMEN WITH A HISTORY OF VAGINAL DELIVERY?

Objectives To evaluate anal sphincter anatomy using three-dimensional ultrasonography (3-DAUS) in incontinent women with vaginal delivery, correlate anatomical findings with symptoms of fecal incontinence and determine the effect of vaginal delivery on anal canal anatomy and function. Methods Female with fecal incontinence and vaginal delivery were assessed with Wexner’s score, manometry, and 3DAUS. A control group comprising asymptomatic nulliparous was included. Anal pressure, the angle of the defect and length of the external anal sphincter (EAS), the anterior and posterior internal anal sphincter (IAS), the EAS + puborectal and the gap were measured and correlated with score. Results Of the 62, 49 had fecal incontinence and 13 were asymptomatic. Twenty five had EAS defects, 8 had combined EAS+IAS defects, 16 had intact sphincters and continence scores were similar. Subjects with sphincter defects had a shorter anterior EAS, IAS and longer gap than women without defects. Those with a vaginal delivery and intact sphincters had a shorter anterior EAS and longer gap than nulliparous. We found correlations between resting pressure and anterior EAS and IAS length in patients with defects. Conclusions Avaliar a anatomia do esfíncter anal usando ultra-sonografia tridimensional (3D-US) em mulheres incontinentes com parto vaginal, correlacionar os achados anatômicos com sintomas de incontinência fecal e, determinar o efeito do parto vaginal sobre a anatomia e função do canal anal.