Effects of age and gender on three-dimensional endoanal ultrasonography measurements: development of normal ranges

Impact of sex and aging on radiographic and functional parameters of the anal sphincter complex in patients with accidental bowel leakage

AIMS

Treatment outcomes for accidental bowel leakage (ABL) may be influenced by age-related sarcopenia. We sought to determine if thickness of the anal sphincter complex on endoanal ultrasound correlated with function in women and men with ABL and if women demonstrated age-related anal sphincter thinning.

METHODS

Consecutive patients with ABL presenting to our pelvic floor clinic from 2012 to 2017 were included. Clinical data were obtained from medical records. External anal sphincter (EAS), imaged by endoanal ultrasound at proximal, mid and distal locations, and IAS thickness were measured at 12, 3, 6, and 9 o'clock; puborectalis muscle (PRM) was measured at 4, 6, and 8 o'clock; and averaged. Anorectal manometry was conducted when clinically indicated. Data were compared using Mann-Whitney tests and linear regression. Results are reported as mean ± SD or median (IQR).

RESULTS

Women (n = 136) were younger than men (n = 26) (61 ± 13 vs. 67 ± 13 years, p = 0.02). More women than men had pelvic surgery and less had colorectal surgery, spinal disorders, or a history of smoking (p < 0.05). Eighty-two percentage of women had an anal sphincter defect versus 31% of men (p < 0.01). All anal sphincter complex components were thinner in women than men with lower squeeze and resting pressures (p < 0.03), even in nulliparous women. Mean resting pressure was lower in older 6.1 (4.6-7.8) versus younger women 8.3 (5.0-12.9) mmHg, p = 0.04.

CONCLUSIONS

Women, even nulliparous, with ABL demonstrate thinner and weaker anal sphincters than men, Aging correlated with an increase in anal sphincter thickness, suggesting that age-related changes in the intrinsic components of the anal sphincter complex associated with ABL are complex and are not always well demonstrated on endoanal ultrasound.

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.

The relationships between the results of contemporary tests of anorectal structure and sensorimotor function and the severity of fecal incontinence

BACKGROUND

Diagnostic investigations for fecal incontinence (FI) assess the structure and sensorimotor function of the anorectum. Investigations include anorectal manometry, anorectal sensory testing, pudendal nerve terminal motor latencies (PNTML), and endoanal sonography. The severity of FI and results of investigations are often discordant and the rate of symptom resolution following treatment remains <40%. High-resolution anorectal manometry (HRAM) and three-dimensional endoanal ultrasound (3D-US) have been introduced during the last decade. This study aims to assess the strength of relationships between contemporary investigation results and FI severity.

METHODS

Adults presenting for investigation of FI were assessed using the St Mark's FI severity score (SMIS), HRAM, anorectal sensory testing, PNTML, and 3D-US.

KEY RESULTS

246 patients were included. There were significant relationships between the SMIS and HRAM (resting pressure r_s = -0.23, 95% CI = (-0.34, -0.11), P < .001; squeeze pressure (r_s  = -0.26, 95% CI = (-0.37, -0.14), P < .001) and 3D-US (anterior EAS length r_s = -0.22, 95% CI = (-0.34, -0.09), P = .001). The relationships between SMIS and HRAM had a greater effect size in those with urge-predominant symptoms (resting pressure: r_s = -0.40, 95% CI = (-0.57, -0.20), P < .001, squeeze pressure: r_s = -0.34, 95% CI = (-0.52, -0.12), P = .003). Overall, the variance in SMIS accounted for by anorectal investigations was 8.6% (R² = 0.098, adjusted R² = 0.086, P < .001).

CONCLUSIONS AND INFERENCES

Anorectal investigations are not strong predictors of FI severity. These findings may reflect the multifactorial, heterogeneous pathophysiology of FI, the limitations of the SMIS and anorectal investigations, and contributing factors extrinsic to the anorectum.

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.

Three-Dimensional Endoanal Ultrasound Features of the Anal Sphincter in Asian Primigravidae

OBJECTIVES

The normal parameters of 3-dimensional endoanal ultrasound (3DEAUS) of the anal sphincter have not been reported for primigravidae or pregnant women at present. 3DEAUS parameters in Asian primigravidae were assessed in this study.

METHODS

We analyzed 3DEAUS data of 101 consecutives Asian primigravidae, assessed in the early third trimester. The assessment was performed with a rigid ultrasonic probe (Olympus^® RU 12M-R1 probe and EU-ME1 ultrasound system (Olympus Corp., Shinjuku, Japan). The Wilcoxon signed-rank test was used to detect the differences in pressure in different quadrants.

RESULTS

The participants had a mean age of 24.7 (standard deviation [SD], 5.1) years. The Cleveland Clinic Incontinence Score was normal in all participants. The anal sphincter complex had 3 characteristic segments that were identifiable: upper, middle and lower. The puborectalis muscle was identified as a striated "V"-shaped sling, and its mean thickness was 7.44 (SD, 1.41) mm. The mean thickness of internal (IAS) and external (EAS) sphincters at the mid-sphincter level were 1.78 (SD, 0.59) and 5.49 (SD, 1.21) mm, respectively. The EAS measured 6.02 (SD, 1.07) mm at the lower sphincter level. The statistically significant differences seen in the in quadrants were: the IAS was thicker anteriorly (Z = -2.642; P = .008), the EAS at both midsphincter level (Z = -3.70; P < .001) and lower sphincter level (Z = -7.712; P < .001) was thicker posteriorly, and the IAS was thicker at the 9 o'clock position (Z = -2.081; P = .037). Good symmetry at all 3 levels was seen in the EAS (including the puborectalis muscle).

CONCLUSIONS

Normal values of 3DEAUS for primigravidae have been identified and may serve as reference values for other laboratories.

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.

Fetal head size and effect of manual perineal protection

OBJECTIVE

The aim of this study was to evaluate whether a previously identified modification of Viennese method of perineal protection remains most effective for reduction of perineal tension in cases with substantially smaller or larger fetal heads.

METHODS

A previously designed finite element model was used to compare perineal tension of different modifications of the Viennese method of perineal protection to "hands-off" technique for three different sizes of the fetal head. Quantity and extent of tension throughout the perineal body during vaginal delivery at the time when the suboccipito-bregmatic circumference passes between the fourchette and the lower margin of the pubis was determined.

RESULTS

The order of effectiveness of different modifications of manual perineal protection was similar for all three sizes of fetal head. The reduction of perineal tension was most significant in delivery simulations with larger heads. The final position of fingers 2cm anteriorly from the fourchette (y = +2) consistently remains most effective in reducing the tension. The extent of finger movement along the anterior-posterior (y-axis) contributes to the effectiveness of manual perineal protection.

CONCLUSION

Appropriately performed Viennese manual perineal protection seems to reduce the perineal tension regardless of the fetal head size, and thus the method seems to be applicable to reduce risk of perineal trauma for all parturients.

Role of three-dimensional endoanal ultrasound in assessing the anal sphincter morphology of female patients with chronic proctalgia

AIM

To assess the role of three-dimensional endoanal ultrasound (3D-EAUS) for morphological assessment of the anal sphincter of female patients with chronic proctalgia (CP).

METHODS

In this unmatched case control study, 30 consecutive female patients with CP and 25 normal women (control group) were enrolled. 3D-EAUS was performed in all subjects. Thickness and length of internal anal sphincter (IAS), thickness of puborectalis muscle (PR), length of the external anal sphincter (EAS) plus PR, and puborectalis angle were measured and compared between the two groups.

RESULTS

Patients with CP had significantly shorter IAS length and greater PR thickness, as compared to those in normal individuals (26.28 ± 3.59 mm vs 28.87 ± 4.84 mm, P < 0.05 and 9.67 ± 1.57 mm vs 8.85 ± 0.97 mm, P < 0.05, respectively). No significant between-group differences were observed with respect to IAS thickness and the EAS plus PR length (P > 0.05). Puborectalis angle in the CP group was significantly decreased, both in resting (88.23° ± 1.81° vs 89.94° ± 2.07° in control group, P < 0.05) and straining (88.47° ± 3.32° vs 90.72° ± 1.87° in control group, P < 0.05) phases, which suggest the presence of paradoxical contraction of PR in patients with CP. In the CP group, no significant difference in puborectalis angle was observed between the resting and straining phases (88.23° ± 1.81° vs 88.47° ± 3.32° respectively, P > 0.05).

CONCLUSION

The association of greater PR thickness and paradoxical contraction of PR with CP suggest their potential value as markers of CP.

Gender differences in chronic constipation on anorectal motility

BACKGROUND

The epidemiology of chronic constipation (CC) skews toward female predominance, yet men make up an important component of those suffering from CC. We sought to determine whether there are sex-specific differences in symptoms and physiologic parameters on anorectal manometry (ARM).

METHODS

We performed a case-control analysis of sequential men and age-matched women (2:1 ratio) presenting for ARM as part of the evaluation of CC. We collected physiologic parameters derived from 3D high-resolution ARM in addition to the ROME III constipation module and the Pelvic Floor Distress Inventory 20 (PFDI-20) questionnaires. We analyzed univariate, sex-specific differences in ARM physiologic parameters and PFDI-20 parameters and adjusted for putative confounders using multivariate logistic regression.

KEY RESULTS

Our study enrolled 80 men and 165 age-matched women. Men had a higher median sphincter resting pressure (81.2 vs 75.2 mm Hg, P=.01) and mean squeeze pressure (257.0 vs 170.5 mm Hg, P<.0001) than women. Although men reported significantly less severe straining and incomplete evacuation, they had greater mean rectoanal pressure differential (-106.7 vs -71.1 mm Hg, P<.0001), smaller mean defecation index (0.17 vs 0.27, P=.03) and higher volume threshold for urgency (115.2 v. 103.4 mL, P=.03). However, women were more likely to have abnormal balloon expulsion time (BET) than men (52.7% vs 35.0%, P=.01). After multivariate analysis, male gender was the only independent predictor of a normal BET (OR: 0.48, 95% CI: 0.27-0.86, P=.01).

CONCLUSIONS & INFERENCES

Men and women with CC differ with regard to symptom severity and physiologic parameters derived from ARM suggesting differences in their pathophysiology.

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.

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.

How much of the internal sphincter may be divided during lateral sphincterotomy for chronic anal fissure in women? Morphologic and functional evaluation after sphincterotomy

BACKGROUND

Sphincterotomy is used to treat chronic anal fissure, but the length of the sphincterotomy is associated with incontinence.

OBJECTIVE

We used 3-dimensional anal ultrasonography to determine the proportion of the internal anal sphincter that may be divided during lateral internal sphincterotomy in women without predisposing them to a high risk of fecal incontinence.

DESIGN AND SETTING

This was a prospective, observational cohort study conducted at a tertiary-care hospital.

PATIENTS

Women treated for chronic anal fissure with high anal resting pressure and no symptoms of fecal incontinence were selected. Asymptomatic women recruited from different departments of the same hospital served as controls to provide reference values for anal canal measurements.

INTERVENTION

Patients underwent a standardized technique of lateral internal sphincterotomy.

MAIN OUTCOME MEASURES

Three-dimensional ultrasonography was used to measure sphincter lengths. Continence was assessed with the Cleveland Clinic Florida (Wexner) score. The relationship between the extent of the surgically divided portion of the internal anal sphincter and the continence score was evaluated.

RESULTS

Successful healing was achieved in all patients within 2 months. Follow-up continence scores were significantly correlated with the extent of sphincter division. The proportion of patients with a continence score of 0 was significantly greater in patients in whom sphincter division was less than 25% in comparison with patients with a division of 25% or more. Anal canal and sphincter lengths in patients after sphincterotomy did not significantly differ from those in asymptomatic women.

LIMITATIONS

The study is limited by its nonrandomized nature and the lack of preoperative ultrasound assessment.

CONCLUSIONS

Based on data from this study, the safe extent of division is less than 25% of the total sphincter length, which in women corresponds to less than 1 cm.

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

AIM

The effect of vaginal delivery and ageing on the anatomy of the anal canal was assessed using three-dimensional anorectal ultrasound to determine the interobserver reliability.

METHOD

One-hundred and eighteen asymptomatic women without sphincter damage were grouped according to parity and mode of delivery. They were then stratified by age (≤50 years vs >50 years). Group I consisted of 35 nulliparous women, of mean ages 36 years (n = 20) and 62 years (n = 15), Group II consisted of multiparous women, having one or more vaginal deliveries (n = 43), of mean ages 43 years (n = 20) and 60 years (n = 23) and Group III consisted of women who had a Caesarean section (n = 40) of mean ages 41 years (n = 20) and 56 years (n = 20). The groups were compared with regard to the length and the thickness of the external anal sphincter, the internal anal sphincter, the posterior external sphincter and the puborectalis in all quadrants and the anterior gap. Interobserver variability was assessed.

RESULTS

In women having vaginal delivery the length of the anterior external sphincter was shorter (P = 0.0004) and the gap was longer (P = 0.0306). The external sphincter tended to be thinner in individuals having vaginal delivery (P = 0.0677) and in those subjects over 50 years of age having had a vaginal delivery (P = 0.0164). In nulliparous women, the internal sphincter was thicker in subjects over 50 years of age (P = 0.0229). The intraclass correlation coefficient was 0.755-0.916 for sphincter muscle and gap length and 0.446-0.769 for muscle thickness.

CONCLUSION

Vaginal delivery was associated with a shorter anterior external sphincter, a longer gap and a thinner anterior external sphincter in asymptomatic women. Age was correlated with sphincter thickness, and nulliparous women >50 years of age had a thicker internal sphincter. Three-dimensional ultrasound was found to be a reliable method for measuring anal structures.

Three-dimensional anal endosonography in depicting anal-canal anatomy

PURPOSE

This report describes the advantages of 3D anal endosonography in depicting the normal anatomy of the anal canal in relation to sex and age.

MATERIALS AND METHODS

A retrospective study was performed of 85 patients, 33 men and 52 women, previously examined with 3D anal ultrasound (US) for clinically suspected anorectal disease but found to be negative. The examinations were performed with a Bruel and Kjaer US system with a 2050 transducer, scanning from the anorectal junction to the subcutaneous portion of the external anal sphincter (EAS). The 3D reconstructions provided an estimation of sphincter length in the anterior and posterior planes, and axial 2D images enabled calculation of the thickness of the internal anal sphincter (IAS) and EAS in the anterior, posterior and lateral transverse planes.

RESULTS

Distribution of the sphincter complex is asymmetric in both sexes: the EAS and IAS are significantly shorter in females, especially in the anterior longitudinal plane (p=0.005 and p<0.001, respectively). EAS and IAS thickness increases with age, especially the lateral IAS (R(2)=0.37, p<0.001) and the posterior EAS (R(2)=0.29, p=0.01).

CONCLUSIONS

A good knowledge of anal-canal anatomy is essential to detect sphincter abnormalities when assessing pelvic floor dysfunction.

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.