The physical properties of rectal contents have effects on anorectal continence: insights from a study into the cause of fecal spotting on orlistat

Novel insights into physiological mechanisms underlying fecal continence

The machinery maintaining fecal continence prevents involuntary loss of stool and is based on the synchronized interplay of multiple voluntary and involuntary mechanisms, dependent on cooperation between motor responses of the musculature of the colon, pelvic floor, and anorectum, and sensory and motor neural pathways. Knowledge of the physiology of fecal continence is key toward understanding the pathophysiology of fecal incontinence. The idea that involuntary contraction of the internal anal sphincter is the primary mechanism of continence and that the external anal sphincter supports continence only by voluntary contraction is outdated. Other mechanisms have come to the forefront, and they have significantly changed viewpoints on the mechanisms of continence and incontinence. For instance, involuntary contractions of the external anal sphincter, the puborectal muscle, and the sphincter of O'Beirne have been proven to play a role in fecal continence. Also, retrograde propagating cyclic motor patterns in the sigmoid and rectum promote retrograde transit to prevent the continuous flow of content into the anal canal. With this review, we aim to give an overview of primary and secondary mechanisms controlling fecal continence and evaluate the strength of evidence.

Review of the indications, methods, and clinical utility of anorectal manometry and the rectal balloon expulsion test

BACKGROUND

Anorectal manometry (ARM) comprehensively assesses anorectal sensorimotor functions.

PURPOSE

This review examines the indications, techniques, interpretation, strengths, and weaknesses of high-resolution ARM (HR-ARM), 3-dimensional high-resolution anorectal manometry (3D-HR-ARM), and portable ARM, and other assessments (i.e., rectal sensation and rectal balloon expulsion test) that are performed alongside manometry. It is based on a literature search of articles related to ARM in adults. HR-ARM and 3D-HR-ARM are useful for diagnosing defecatory disorders (DD), to identify anorectal sensorimotor dysfunction and guide management in patients with fecal incontinence (FI), constipation, megacolon, and megarectum; and to screen for anorectal structural (e.g., rectal intussusception) abnormalities. The rectal balloon expulsion test is a useful, low-cost, radiation-free, outpatient assessment tool for impaired evacuation that is performed and interpreted in conjunction with ARM. The anorectal function tests should be interpreted with reference to age- and sex-matched normal values, clinical features, and results of other tests. A larger database of technique-specific normal values and newer paradigms of analyzing anorectal pressure profiles will increase the precision and diagnostic utility of HR-ARM for identifying abnormal mechanisms of defecation and continence.

THE FATIGUE RATE INDEX IS HIGHER IN CHILDREN WITH FUNCTIONAL CONSTIPATION AND RETENTIVE FECAL INCONTINENCE

BACKGROUND

The Fatigue Rate Index (FRI) is a parameter in anorectal manometry (ARM) to assess sustained voluntary contraction, considering the squeeze pressure and fatigability of the external anal sphincter. It is used in adults to detect fecal incontinence even in patients who present normal squeeze pressures. The FRI in adult patients with functional constipation is similar to controls.

OBJECTIVE

The aim of this study was to evaluate the feasibility and values of FRI in children in relation to the values previously established in adults and comparing children with functional constipation and retentive fecal incontinence to children without retentive fecal incontinence.

METHODS

This retrospective study evaluated 105 ARM performed from Jan 2014 to Apr 2015. 42 patients were selected (were able to perform a voluntary contraction and had no co-morbidities other than functional constipation). 14 (33.3%) of those collaborated in sustaining contraction for 40 seconds (s), allowing the evaluation of the FRI. Patients with retentive fecal incontinence secondary to functional constipation (n=7, aged 6 to 13 years, six boys) were our interest group. Patients with functional constipation without fecal incontinence (n=7, aged 6 to 13 years, four boys) were considered a reference group. The ARM were performed with a radial eight-channel perfusion catheter (DynamedTM, São Paulo, Brazil) and the FRI was calculated (Proctomaster 6.4) in the first 20 s and overall 40 s of sustained voluntary contraction.

RESULTS

14 of the selected 42 collaborated in sustaining contraction for 40 s, allowing the evaluation of the FRI. In the first 20 s of contraction, the fecal incontinence group showed a significantly higher mean FRI (2.48±1.39 min) compared to the reference group (1.13±0.72 min, P=0.042), which was not observed in the 40 s interval due to less uniform contraction. The anal resting pressure was higher in the fecal incontinence group (76.83 mmHg) than in the reference group (54.13 mmHg), but the statistical study did not reach significance (P=0.051).

CONCLUSION

The FRI is feasible in children. The mean FRI obtained in this study is lower than the reported in constipated adults. The mean FRI among children with functional constipation and retentive fecal incontinence is higher than among constipated children without retentive fecal incontinence.

Anorectal dysfunction in multiple sclerosis patients: A pilot study on the effect of an individualized rehabilitation approach

BACKGROUND:

Anorectal dysfunction (ARD), especially bowel incontinence, frequently compromises the quality of life in multiple sclerosis (MS) patients. The effect of rehabilitation procedures has not been clearly established.

OBJECTIVE:

To determine the effect of an individualized rehabilitation approach on bowel incontinence and anorectal pressures.

METHODS:

MS patients with ARD underwent 6-months of individually targeted biofeedback rehabilitation. High resolution anorectal manometry (HRAM) and St. Mark’s Fecal Incontinence Scores (SMIS) were completed prior to rehabilitation, after 10 weeks of supervised physiotherapy, and after 3 months of self-treatment.

RESULTS:

Ten patients (50%) completed the study. Repeated measures analysis of variance (ANOVA) demonstrated significant improvement in the SMIS questionnaire over time [14.00 baseline vs. 9.70 after supervised physiotherapy vs. 9.30 after self-treatment (p = 0.005)]. No significant improvements over time were noted in any HRAM readings: maximal pressure [49.85 mmHg baseline vs. 57.60 after supervised physiotherapy vs. 60.88 after self-treatment (p = 0.58)], pressure endurance [36.41 vs. 46.89 vs. 49.95 (p = 0.53)], resting pressure [55.83, vs 52.69 vs. 51.84 (p = 0.704)], or area under the curve [230.0 vs. 520.8 vs. 501.9 (p = 0.16)].

CONCLUSIONS:

The proposed individualized rehabilitation program supports a positive overall effect on anorectal dysfunction in MS patients.

Does Bariatric Surgery Improve Faecal Incontinence? A Systematic Review and Meta-analysis

Introduction

Obesity increases the risk of pelvic floor disorders in individuals with obesity, including faecal incontinence. Faecal incontinence (FI) is a condition with important clinical and psychosocial consequences. Though it is associated with obesity, the effect of bariatric surgery on the prevalence and severity of FI is not well reported.

Objective

To assess the effect of bariatric surgery on the prevalence and severity of FI in adult patients with obesity.

Methods

This systematic review was conducted in accordance with the PRISMA statement. Two independent reviewers performed a literature search in MEDLINE, PubMed, Cochrane and Embase from 1 January 1980 to 12 January 2019. We included published English-language randomized control trials and observational studies assessing pre- and post-bariatric surgery prevalence or severity of FI. Random-effects models with DerSimonian and Laird’s variance estimator were used for meta-analysis.

Results

Thirteen studies were included, eight assessing prevalence (678 patients) and 11 assessing severity of FI (992 patients). There was no significant difference in prevalence post-operatively overall, though it trended towards a reduction [pooled OR=0.55; =0.075]. There was a significant reduction of FI prevalence in women post-bariatric surgery [95% CI 0.22 to 0.94, p=0.034]. There was a statistically significant reduction in FI prevalence following Roux-en-Y gastric bypass and one anastomosis gastric bypass [0.46, 95% CI 0.26 to 0.81; p=0.007]. There was no significant reduction of incontinence episodes post-operatively [pooled mean difference =−0.17, 95% CI −0.90 to 0.56; p=0.65]. Quality of life (QOL) was not significantly improved post-bariatric surgery [mean differences for the following facets of QOL: behaviour −0.35, 95% CI −0.94 to 0.24; depression 0.04, 95% CI −0.12 to 0.2; lifestyle −0.33, 95% CI −0.98 to 0.33; p values of 0.25, 0.61 and 0.33, respectively].

Discussion

There was a significant reduction in FI prevalence in women and those who underwent Roux-en-Y or one anastomosis gastric bypass. Our results for FI prevalence overall, FI severity and impact on quality of life were not statistically significant. Larger studies are needed in this under-researched area to determine the true effect of bariatric surgery on FI.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11695-021-05360-7.

How to Perform and Interpret a High-resolution Anorectal Manometry Test

High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) catheters have closely spaced water-perfused or solid state circumferentially-oriented pressure sensors that provide much better spatiotemporal pressurization than non-high resolution catheters. This is a comprehensive review of HR-ARM and HD-ARM anorectal manometry catheter systems, the methods for conducting, analyzing, and interpreting HR-ARM and HD-ARM, and a comparison of HR-ARM with non-high resolution anorectal manometry. Compared to non-high resolution techniques, HR-ARM and HD-ARM studies take less time and are easier to interpret. However, HR-ARM and HD-ARM catheters are more expensive and fragile and have a shorter lifespan. Further studies are needed to refine our understanding of normal values and to rigorously evaluate the incremental clinical utility of HR-ARM or HD-ARM compared to non-high resolution manometry.

Relationship Among Anal Sphincter Injury, Patulous Anal Canal, and Anal Pressures in Patients With Anorectal Disorders

BACKGROUND & AIMS

The anal sphincters and puborectalis are imaged routinely with an endoanal magnetic resonance imaging (MRI) coil, which does not assess co-aptation of the anal canal at rest. By using a MRI torso coil, we identified a patulous anal canal in some patients with anorectal disorders. We aimed to evaluate the relationship between anal sphincter and puborectalis injury, a patulous anal canal, and anal pressures.

METHODS

We performed a retrospective analysis of data from 119 patients who underwent MRI and manometry analysis of anal anatomy and pressures, respectively, from February 2011 through March 2013 at the Mayo Clinic. Anal pressures were determined by high-resolution manometry, anal sphincter and puborectalis injury was determined by endoanal MRI, and anal canal integrity was determined by torso MRI. Associations between manometric and anatomic parameters were evaluated with univariate and multivariate analyses.

RESULTS

Fecal incontinence (55 patients; 46%) and constipation (36 patients; 30%) were the main indications for testing; 49 patients (41%) had a patulous anal canal, which was associated with injury to more than 1 muscle (all P ≤ .001), and internal sphincter (P < .01), but not puborectalis (P = .09) or external sphincter (P = .06), injury. Internal (P < .01) and external sphincter injury (P = .02) and a patulous canal (P < .001), but not puborectalis injury, predicted anal resting pressure. A patulous anal canal was the only significant predictor (P < .01) of the anal squeeze pressure increment.

CONCLUSIONS

Patients with anorectal disorders commonly have a patulous anal canal, which is associated with more severe anal injury and independently predicted anal resting pressure and squeeze pressure increment. It therefore is important to identify a patulous anal canal because it appears to be a marker of not only anal sphincter injury but disturbances beyond sphincter injury, such as damage to the anal cushions or anal denervation.

Retention test in sacral nerve stimulation for fecal incontinence

INTRODUCTION

Sacral nerve stimulation has become an established treatment for patients with fecal incontinence. However, the mechanism of its action remains obscure. We aim to assess whether sacral nerve stimulation improves patients' ability to retain rectal content.

METHODS

Patients who had been treated successfully with sacral nerve stimulation underwent four retention tests during which the stimulator was turned either on or off. Both the patients and investigators were blinded to the status of the stimulator. The retention test results were assessed for interassessment agreement and for any differences between the on and off phases. Wexner scores, anorectal physiology tests, and patients' perceptions of stimulator settings were also recorded.

RESULTS

Nineteen patients (16 women; mean age, 57.5 years) took part in the study. Retention tests showed moderate interassessment agreement (weighted Cohen's kappa index, 0.45). There were no sharp differences in retained volume between the stimulator's on and off phases (median 50 (range, 0-300) mL vs. 50 (range, 0-300) mL; P = 0.85).

CONCLUSION

Sacral nerve stimulation does not alter patients' ability to retain rectal content. Further studies are needed to investigate the mechanism of sacral nerve stimulation.

Fecal incontinence and biofeedback therapy

Biofeedback as delivered in most clinical settings in Western medicine has been consistently reported to improve symptoms of fecal incontinence. Closer scrutiny of the elements of the intervention and controlled studies, however, have consistently failed to find any benefit of the biofeedback element of this complex package of care; nor has any superiority been found for one modality over another. There is a need for further well-designed and adequately powered randomized controlled trials. Meanwhile, there can be little doubt that conservative interventions improve many patients with fecal incontinence to the point where most report satisfaction with treatment and do not wish to consider more invasive options, such as surgery.

Relation of bowel habits to fecal incontinence in women

BACKGROUND

Though most women with fecal incontinence (FI) have anorectal dysfunctions, a majority have intermittent symptoms. Variations in bowel habits and daily routine may partly explain this.

AIM

To compare bowel habits and daily routine between controls and FI, and between continent and incontinent stools among women with FI.

METHOD

Using a mailed questionnaire, we identified 507 women with FI among 5,300 women in Olmsted County, MN. Bowel habits were compared among 127 randomly selected controls and 154 women with self-reported FI, who did ("active" FI, N = 106) or did not ("inactive" FI, N = 48) have an incontinent episode during a 2-wk bowel diary period.

RESULTS

Independent risk factors for FI were: rectal urgency (odds ratio [OR] for inactive FI vs controls 5.6, 95% confidence interval [CI] 2.3-13.3; and OR for active FI vs inactive FI 2.0, 95% CI 0.9-4.3) and a sense of incomplete evacuation (OR for inactive FI vs controls 3.5, 95% CI 1.4-8.8; and OR for active FI vs inactive FI 2.2, 95% CI 1.1-4.9). Similar results were found for stool frequency and form. Among incontinent women, incontinent stools (versus continent stools) were less formed, more likely to occur at work, and to be preceded by rectal urgency.

CONCLUSIONS

Bowel patterns, rectal urgency, and daily routine influence the occurrence of FI. Stool characteristics explained 46% of the likelihood for incontinence episodes, emphasizing that anorectal sensorimotor dysfunctions must also contribute to FI in women.

Investigation to predict faecal continence in patients undergoing reversal of a defunctioning stoma (Porridge enema test)

OBJECTIVE

A defunctioning stoma is often performed in cases of major anorectal surgery or sphincter injury. This study aimed to assess the Porridge enema (PE) test as a tool to evaluate function prior to stoma closure.

METHOD

Thirty-eight patients underwent PE test at a median of 12.5 months after stoma formation prior to consideration of stoma closure. Outcome was assessed by immediate leakage after PE test on lying, standing, walking and the ability to hold the enema for 30 min. Patients available for follow-up were divided into two groups: group 1 (n = 20) patients with stoma closure performed and group 2 (n = 10) patients where the stoma remains. Eight patients were excluded from analysis as the stoma had not been reversed for reasons unrelated to continence. The results of other investigations performed in these patients were analysed. Finally, we studied the agreement in the interpretation of the test by two investigators blinded to the patient's group and each other's interpretation and to functional results after the stoma was reversed.

RESULTS

Anorectal physiology testing and imaging assessment of the anal sphincters was not statistically different between the two groups. There was a significant difference in the percentage of patients in each group that had enema leakage in: lying position (P = 0.002), standing position (P = 0.013), walking (P = 0.002) and ability to defer for 30 min (P = 0.005). There was a good correlation in the interpretation of PE test results by two investigators. Among patients whose stoma was closed and who were evaluated functionally, 55% were fully continent.

CONCLUSION

This report suggests that the PE test is a promising tool as part of evaluation of anorectal function prior to stoma reversal.