Normal values for assessment of anal sphincter morphology, anorectal motion, and pelvic organ prolapse with MRI in healthy women

Centrally Distributed Adiposity as a Modifiable Risk Factor for Fecal Incontinence: United States Population-based Analysis

BACKGROUND AND AIMS

Fecal incontinence (FI) is highly prevalent with substantial impacts on quality of life and health care utilization. The impact of obesity on FI remains unclear, with differing conclusions using body mass index (BMI) as a risk factor. We aimed to determine the association between obesity and FI, and whether this relationship is dependent on the distribution of adiposity (waist circumference-to-height ratio [WHtR]).

METHODS

This was a population-based analysis of the National Health and Nutrition Examination Survey, including participants who responded to the bowel health survey in 2005 to 2010. FI was defined by the accidental bowel leakage of solid stool, liquid, or mucus at least once in the past month. Stepwise multivariable logistic regression models were constructed to assess risk factors for FI.

RESULTS

A total of 7606 participants were included, with an overall FI prevalence of 9.2%. When stratified by quartiles of body measurements, FI was increasingly prevalent from the 1st to the 4th quartile for both WHtR (range, 5.3%-12.5%) and BMI (range, 7.1%-10.5%). WHtR was associated with FI and was a stronger predictor than BMI in all quartiles of body measurement. On multivariable analysis, WHtR remained a significant predictor of FI comparing the 4th with the 1st quartile of body measurements (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.11-2.80; P = .017), whereas BMI was not. A WHtR cutoff of >0.592 optimized the Youden index in prediction of FI in the overall sample.

CONCLUSION

WHtR was independently associated with increased odds of FI in this nationally representative sample of United States adults, whereas BMI was not consistently correlated. This suggests bowel continence may depend more on how body mass is distributed.

Consistency of Feces Affects Defecatory Function

Background/Aims

It is a common belief that constipated patients have hard feces that contributes to the difficulties defecating. To the best of our knowledge, no studies had been published on controlled evacuation of simulated feces with different consistencies.

Methods

Twelve normal subjects were recruited for studies with the simulated feces device "Fecobionics" of different consistency (silicone shore 0A-40A corresponding to Bristol stool form scale types 2-4). The subjects filled out questionnaires and had the balloon expulsion test and anorectal manometry done for reference. The Fecobionics probes were inserted in rectum in random order with +20 minutes between insertions. The bag was filled to urge-to-defecate and evacuations took place in privacy. Non-parametric statistics with median and quartiles are provided.

Results

One subject was excluded due to technical issues, and another had abnormal anorectal manometry-balloon expulsion test. The 4 females/6 males subjects were aged 23 (range 20-48) years. Most differences were observed between the 0A and 10A probe (duration, maximum bag pressure, duration x maximum bag pressure, and relaxation of the front pressure and the bend angle during evacuation), eg, the duration was 9 (8-12) seconds at 0A and 18 (12-21) seconds at 10A (P < 0.05), and maximum bag pressure was 107 (96-116) cmH2O at 0A and 140 (117-162) cmH2O at 10A (P < 0.05). The bend angle before evacuation differed between the probes whereas only the 10A differed from 40A during defecation. The 10A was harder to evacuate than the 0A probe. Except for the bend angles, no further significant change was observed from 10A to 40A.

Conclusion

Fecal consistency affects defecatory parameters.

Physiology of lower gastrointestinal tract

BACKGROUND

The lower gastrointestinal (GI) tract, formed from the midgut and hindgut, encompasses the colon, rectum and anal canal.

AIM

The aim of this review is to provide an overview of the anatomy and physiology of the lower GI tract.

METHODS

Literature review on anatomy and physiology of the lower GI tract, including normal motility and phases of defecation. It derives its blood supply from the superior and inferior mesenteric arteries while it is innervated by the extrinsic autonomic (the thoracolumbar and sacral nerves) and the intrinsic enteric nervous system. The colon has four layers: mucosa, submucosa, muscularis externa and serosa. The anal canal ends in the internal and external anal sphincters (EASs) involved in continence and defecation. The lower GI tract is predominantly involved in digestion, absorption, defecation and protection. Defecation is a complex process that requires inter-neural (enteric and autonomic nervous systems), neurohormonal and neuromuscular coordination. It has four phases which include basal, pre-expulsive, expulsive and end phase. High-propagating contractions in the colon propel stool to the rectum leading to rectal distention and the recruitment of the recto-anal inhibitory reflex. Once able, the EAS, under full conscious control, is then relaxed allowing stool to be evacuated. Other defecation reflexes include the gastrocolic, gastroileal and coloanal reflexes.

CONCLUSIONS

Recent advances provide novel techniques to investigate motility patterns including high-resolution manometry protocols with automated assessments, magnetic resonance imaging techniques for defecography, wireless motility capsules and fecobionics.

Analysis of minimal levator ani hiatus area based on MRI in female adults without pelvic floor dysfunction at different age groups

PURPOSE

To investigate the association of minimal levator ani hiatus area with age in female adults without pelvic floor dysfunction.

METHODS

532 female subjects aged 18 ~ 90 years without pelvic floor dysfunction, divided into four groups (Group A, 18 ~ 29 years old; Group B, 30 ~ 39 years old; Group C, 40 ~ 49 years old; Group D, ≥ 50 years old) based on age, underwent traditional pelvic two-dimensional (2D) T2-weighted imaging (T2WI) axial to the body (AxB) for measuring the minimal levator ani hiatus area. 39 female volunteers were re-recruited to undergo both traditional pelvic 2D T2WI AxB and three-dimensional (3D) T2WI. An axial plane parallel to the direction of the puborectalis muscle (AxPRM) was acquired based on 3D T2WI. The difference of levator ani hiatus area measured on AxB and AxPRM images in 39 female volunteers was compared by one-sample t test, to verify if minimal levator ani hiatus area can be acquired on the traditional pelvic 2D T2WI AxB images. Spearman analysis evaluated the association of minimal levator ani hiatus area with age and the rank-sum test analyzed the area differences among four age groups.

RESULTS

Female age was positively correlated with minimal levator ani hiatus area (r = 0.23; p < 0.001). The minimal levator ani hiatus areas of 532 subjects were: 15.17 ± 1.77 cm2 in Group A, 15.52 ± 2.21 cm2 in Group B, 16.03 ± 2.16 cm2 in Group C, and 16.40 ± 2.10 cm2 in Group D. ANOVA showed significant statistical differences among four age groups (F = 7.519, p < 0.0001). Significant differences in minimal levator ani hiatus areas were found between Group A and Group C (p = 0.0491), Group A and Group D (p = 0.0007), and Group B and Group D (p < 0.001). There was no statistical difference in minimal levator ani hiatus areas measured on AxB and AxPRM images in 39 female volunteers (p = 0.1000). There were no statistical difference in minimal levator ani hiatus areas between nulliparous and multiparous group for each age group (all p > 0.05).

CONCLUSIONS

Based on a large sample, this study summarized the minimum levator ani hiatus area of female adults without pelvic floor dysfunction in different age groups. We found significant differences among different age groups. In addition, a positive correlation was found between age and the minimum levator ani hiatus area. These findings can provide reference criteria for diagnosing pelvic organ prolapse in female adults of different age groups.

Increased Grades of Rectal Intussusception: Role of Decline in Pelvic Floor Integrity and Association With Dyssynergic Defecation

INTRODUCTION

The natural history of rectal intussusception (RI) is poorly understood. We hypothesized that decline in pelvic floor integrity and function leads to increasing RI grades.

METHODS

Retrospective analysis of a registry of patients with defecatory disorders with high-resolution anorectal manometry and magnetic resonance defecography was performed. Association of risk factors on increasing RI grades was assessed using logistic regression.

RESULTS

Analysis included a total of 238 women: 90 had no RI, 43 Oxford 1-2, 49 Oxford 3, and 56 Oxford 4-5. Age ( P = 0.017), vaginal delivery ( P = 0.008), and prior pelvic surgery ( P = 0.032) were associated with increased Oxford grades. Obstructive defecation symptoms and dyssynergic defecation were observed at relatively high rates across groups. Increased RI grades were associated with less anal relaxation at simulated defecation yet, higher rates of normal balloon expulsion ( P < 0.05), linked to diminished anal sphincter. Indeed, increased RI grades were associated with worsening fecal incontinence severity, attributed to higher rates of anal hypotension. Levator ani laxity, defined by increased levator hiatus length and its excessive descent at straining, was associated with increasing RI grades, independent of age, history of vaginal delivery, and pelvic surgeries and could independently predict increased RI grades. Concurrent anterior and posterior compartments, and visceral prolapse were associated with higher Oxford grades.

DISCUSSION

Our data suggest that decline in pelvic floor integrity with abnormal levator ani laxity is associated with increased RI grades, a process that is independent of age, history of vaginal deliveries, and/or pelvic surgeries, and perhaps related to dyssynergic defecation.

Global Prevalence of Fecal Incontinence in Community-Dwelling Adults: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Fecal incontinence (FI) can considerably impair quality of life. Through a systematic review and meta-analysis, we sought to determine the global prevalence and geographic distribution of FI and to characterize its relationship with sex and age.

METHODS

We searched PubMed, Web of Science, and Cochrane Library databases to identify population-based surveys of the prevalence of FI.

RESULTS

Of the 5175 articles identified, the final analysis included 80 studies; the median response rate was 66% (interquartile range [IQR], 54%-74%). Among 548,316 individuals, the pooled global prevalence of FI was 8.0% (95% confidence interval [CI], 6.8%-9.2%); by Rome criteria, it was 5.4% (95% CI, 3.1%-7.7%). FI prevalence was greater for persons aged 60 years and older (9.3%; 95% CI, 6.6%-12.0%) compared with younger persons (4.9%; 95% CI, 2.9%-6.9%) (odds ratio [OR], 1.75; 95% CI, 1.39-2.20), and it was more prevalent among women (9.1%; 95% CI, 7.6%-10.6%) than men (7.4%; 95% CI, 6.0%-8.8%]) (OR, 1.17; 95% CI, 1.06-1.28). The prevalence was highest in Australia and Oceania, followed by North America, Asia, and Europe, but prevalence could not be estimated in Africa and the Middle East. The risk of bias was low, moderate, and high for 19 (24%), 46 (57%), and 15 (19%) studies, respectively. Exclusion of studies with high risk of bias did not affect the prevalence of FI or heterogeneity. In the meta-regression, the high study heterogeneity (I2 = 99.61%) was partly explained by age.

CONCLUSIONS

Approximately 1 in 12 adults worldwide have FI. The prevalence is greater among women and older people.

The Clinical Impact of Obesity in Patients With Disorders of Defecation: A Cross-Sectional Study of 1,155 Patients

INTRODUCTION

Obesity is a global epidemic. Its clinical impact on symptoms of fecal incontinence (FI) and/or constipation and underlying anorectal pathophysiology remains uncertain.

METHODS

This is a cross-sectional study of consecutive patients meeting Rome IV criteria for FI and/or functional constipation, with data on body mass index (BMI), attending a tertiary center for investigation between 2017 and 2021. Clinical history, symptoms, and anorectal physiologic test results were analyzed according to BMI categories.

RESULTS

A total of 1,155 patients (84% female) were included in the analysis (33.5% normal BMI; 34.8% overweight; and 31.7% obese). Obese patients had higher odds of FI to liquid stools (69.9 vs 47.8%, odds ratio [OR] 1.96 [confidence interval: 1.43-2.70]), use of containment products (54.6% vs 32.6%, OR 1.81 [1.31-2.51]), fecal urgency (74.6% vs 60.7%, OR 1.54 [1.11-2.14]), urge FI (63.4% vs 47.3%, OR 1.68 [1.23-2.29]), and vaginal digitation (18.0% vs 9.7%, OR 2.18 [1.26-3.86]). A higher proportion of obese patients had Rome criteria-based FI or coexistent FI and functional constipation (37.3%, 50.3%) compared with overweight patients (33.8%, 44.8%) and patients with normal BMI (28.9%, 41.1%). There was a positive linear association between BMI and anal resting pressure (β 0.45, R 2 0.25, P = 0.0003), although the odds of anal hypertension were not significantly higher after Benjamini-Hochberg correction. Obese patients more often had a large clinically significant rectocele (34.4% vs 20.6%, OR 2.62 [1.51-4.55]) compared with patients with normal BMI.

DISCUSSION

Obesity affects specific defecatory (mainly FI) and prolapse symptoms and pathophysiologic findings (higher anal resting pressure and significant rectocele). Prospective studies are required to determine whether obesity is a modifiable risk factor of FI and constipation.

[Imaging of the pelvic floor (MR defecography) : The surgeon's perspective]

BACKGROUND

Magnetic resonance defecography (MRD) plays a central role in diagnosing pelvic floor functional disorders by visualizing the entire pelvic floor along with pelvic organs and providing functional assessment of the defecation process. A shared understanding between radiology and surgery regarding indications and interpretation of findings is crucial for optimal utilization of MRD.

OBJECTIVES

This review aims to explain the indications for MRD from a surgical perspective and elucidate the significance of radiological findings for treatment. It intends to clarify for which symptoms MRD is appropriate and which criteria should be followed for standardized results. This is prerequisite to develop interdisciplinary therapeutic approaches.

MATERIALS AND METHODS

A comprehensive literature search was conducted, including current consensus guidelines.

RESULTS

MRD can provide relevant findings in the diagnosis of fecal incontinence and obstructed defecation syndrome, particularly in cases of pelvic floor descent, enterocele, intussusception, and pelvic floor dyssynergia. However, rectocele findings in MRD should be interpreted with caution in order to avoid overdiagnosis.

CONCLUSION

MRD findings should never be considered in isolation but rather in conjunction with patient history, clinical examination, and symptomatology since morphology and functional complaints may not always correlate, and there is wide variance of normal values. Interdisciplinary interpretation of MRD results involving radiology, surgery, gynecology, and urology, preferably in the context of pelvic floor conferences, is recommended.

Defecatory Function Studies Using the Fecobionics Device Are Repeatable

BACKGROUND

Only limited data exist on repeatability of anorectal studies with the established physiological and clinical technologies for assessment of anorectal function. Fecobionics is a new multi-sensor simulated feces that provide data by integrating elements from current tests.

AIMS

To study repeatability of anorectal data obtained with the Fecobionics device.

METHODS

We assessed the database of Fecobionics studies to determine how many repeated studies were done. From a total of 260 Fecobionics studies, 19 subjects with repeated studies using approximately the same protocol and prototype were identified. Key pressure and bending parameters were assessed and the repeatability analyzed using Bland Altman plots. Furthermore, the inter- and intra-individual coefficient of variation (CV) were computed.

RESULTS

Fifteen subjects (5F/10 M) with repeated studies were normal subjects, three were patients with fecal incontinence and one subject suffered from chronic constipation. The main analysis was conducted on the cohort of normal subjects. The bias for 11 parameters were within the confidence interval, whereas two were slightly outside. The interindividual CV was lowest for the bend angle (10.1-10.7) and between 16.3 and 51.6 for the pressure parameters. The intra-individual CVs were approximately half of the inter-individual CVs, spanning from 9.7 to 27.6.

CONCLUSION

All data from normal subjects were within previously defined normality. The Fecobionics data showed acceptable repeatability with bias within the confidence limits for almost all parameters. The intra-individual CV was much lower than the inter-individual CV. Dedicated large-scale studies are warranted to evaluate the influence of age, sex, and disease on repeatability as well as comparing between technologies.

Reproducibility of the anorectal angle with transperineal ultrasound

Background

The anorectal angle (ARA) has been assessed with different imaging methods and its measurement has traditionally been based on defecography or magnetic resonance studies. Different ultrasound methodologies have also been used for ARA assessment and have been validated as alternatives for the ARA measurement, such as three-dimensional (3D) endovaginal ultrasound and 3D transperineal ultrasound. 3D transperineal ultrasound does not require the introduction of ultrasound transducers inside the anal canal. Therefore, it is reasonable to think that the use of transperineal ultrasound can provide more reproducible ARA measurements, something that has not been established by 3D endovaginal probe or defecography. Our objective is to determine the intraobserver and interobserver variability of transperineal ultrasound for the assessment of ARA.

Methods

A retrospective observational study was performed with 40 patients. The study of the ARA was performed from the mid-sagittal plane (at rest, Valsalva and maximum contraction), visualizing the anorectal canal, the anorectal junction and the rectal ampulla. ARA measurements were performed initially by explorer 1 (E1), subsequently by explorer 2 (E2) and finally again by E1. Intraobserver and interobserver variability was calculated by calculating the intraclass correlation coefficient (ICC) with 95% confidence interval (CI).

Results

Intraobserver variability was excellent for all measurements of the ARA at rest, Valsalva and maximal contraction, with ICC ranging from 0.968 to 0.975. Interobserver variability was also superb for all measurements of the ARA at rest, Valsalva and maximal contraction, with ICC ranging from 0.971 to 0.979.

Conclusions

Intraobserver and interobserver variability were excellent for the ARA measurements by transperineal ultrasound.

Recto-anal Pressures in Constipated Men and Women Undergoing High-Resolution Anorectal Manometry

BACKGROUND

In constipated individuals, high-resolution anorectal manometry (HRM) may suggest the presence of a defecatory disorder. Despite known physiological differences between men and women, our understanding of functional anorectal pathophysiology is based upon predominantly female cohorts. Results are generalized to men.

AIMS

To evaluate whether recto-anal pressure patterns in constipated men are similar to those in constipated women.

METHODS

The electronic health records at Mayo Clinic, Rochester were used to identify constipated adult patients, without organic anorectal disease, who had undergone HRM and balloon expulsion testing (BET) in 2018, 2019, and 2020. Comparative analyses were performed.

RESULTS

Among 3,298 constipated adult patients (2,633 women, 665 men), anal and rectal pressures were higher in men. Women more likely to have HRM findings suggestive of a defecatory disorder (39% versus 20%, P < 0.001). Women were more likely to exhibit a type 4 pattern (27% versus 14%, P < 0.001), and less likely to exhibit a type 1 pattern (14% versus 38%, P < 0.001), of dyssynergia. Men were more likely to have an abnormal balloon expulsion test (BET, 34% versus 29%, P = 0.006). Nominal logistic regression demonstrates that male sex, age over 50 years, reduced recto-anal gradient during simulated evacuation, and types 2 and 4 dyssynergia are associated with an abnormal BET.

CONCLUSIONS

In this large retrospective study, constipated men and women exhibited different patterns of dyssynergia both in the presence and absence of an abnormal BET. These findings were independent of sex-specific baseline physiological differences.

Comparison of Anorectal Manometry, Rectal Balloon Expulsion Test, and Defecography for Diagnosing Defecatory Disorders

BACKGROUND & AIMS

The utility of high-resolution anorectal manometry (HR-ARM) for diagnosing defecatory disorders (DDs) is unclear because healthy people may have features of dyssynergia. We aimed to identify objective diagnostic criteria for DD and to ascertain the utility of HR-ARM for diagnosing DD.

METHODS

Constipated patients were assessed with HR-ARM and rectal balloon expulsion time (BET), and a subset underwent defecography. Normal values were established by assessing 184 sex-matched healthy individuals. Logistic regression models evaluated the association of abnormal HR-ARM findings with prolonged BET and reduced rectal evacuation (determined by defecography).

RESULTS

A total of 474 constipated individuals (420 women) underwent HR-ARM and BET, and 158 underwent defecography. BET was prolonged, suggesting a DD, for 152 patients (32%). Rectal evacuation was lower for patients with prolonged vs normal BET. A lower rectoanal gradient during evacuation, reduced anal squeeze increment, and reduced rectal sensation were independently associated with abnormal BETs; the rectoanal gradient was 36% sensitive and 85% specific for prolonged BET. A lower rectoanal gradient and prolonged BET were independently associated with reduced evacuation. Among constipated patients, the probability of reduced rectal evacuation was 14% when the gradient and BET were both normal, 45% when either was abnormal, and 75% when both variables were abnormal.

CONCLUSIONS

HR-ARM, BET, and defecography findings were concordant for constipated patients, and reduced rectoanal gradient was the best HR-ARM predictor of prolonged BET or reduced rectal evacuation. Prolonged BET, reduced gradient, and reduced evacuation each independently supported a diagnosis of DD in constipated patients. We propose the terms probable DD for patients with an isolated abnormal gradient or BET and definite DD for patients with abnormal results from both tests.

Rectocele: Incidental or important? Observe or operate? Contemporary diagnosis and management in the multidisciplinary era

BACKGROUND

More common in older women than younger women, rectoceles may be secondary to pelvic floor weakness and/or pelvic floor dysfunction with impaired rectal evacuation. Rectoceles may be small (<2 cm), medium (2-4 cm), or large (>4 cm). Arguably, large rectoceles are more likely to be associated with symptoms (e.g., difficult defecation). It can be challenging to ascertain the extent to which a rectocele is secondary to pelvic floor dysfunction and/or whether a rectocele, rather than associated pelvic floor dysfunction, is responsible for symptoms. Surgical repair should be considered when initial treatment measures (e.g., bowel modifying agents and pelvic floor biofeedback therapy) are unsuccessful.

PURPOSE

We summarize the clinical features, diagnosis, and management of rectoceles, with an emphasis on outcomes after surgical repair. This review accompanies a retrospective analysis of outcomes after multidisciplinary, transvaginal rectocele repair procedures undertaken by three colorectal surgeons in 215 patients at a large teaching hospital in the UK. A majority of patients had a large rectocele. Some patients also underwent an anterior levatorplasty and/or an enterocele repair. All patients were jointly assessed, and some patients underwent surgery by colorectal and urogynecologic surgeons. In this cohort, the perioperative data, efficacy, and harms outcomes are comparable with historical data predominantly derived from retrospective series in which patients had a good outcome (67%-78%), symptoms of difficult defecation improved (30%-50%), and patients had a recurrent rectocele 2 years after surgery (17%). Building on these data, prospective studies that rigorously evaluate outcomes after surgical repair are necessary.

Anorectal volume-pressure relations, contraction work, and flow during defecation

Fecobionics is an integrated device that has shown promise for assessment of anorectal function. We used a wireless Fecobionics prototype to visualize defecatory patterns and to compute volume-pressure, contraction work, and flow. Twelve normal subjects were studied. The probe was 10 cm-long and contained pressure sensors and electrodes for impedance planimetry. Pressures, diameters, and volume data during defecation were analyzed. The bag was distended inside rectum to the urge-to-defecate level where after the subjects were asked to evacuate. The contraction work and defecatory flow were computed from the volume changes during expulsion. The minimum anal diameter during the evacuation was 17.6 ± 1.5 mm. The middle diameter recording was 10-20% lower than the front diameter channels and 10-20% bigger than the rear channels. The bag volume at urge correlated with the minimum diameter (r = 0.63). The diameter-pressure and volume-pressure loops were counterclockwise with phases of bag filling, isometric contraction, ejection and anal passage. The defecatory contraction work was 3520 ± 480 mL × cmH2O. The maximum flow during defecation was 302 ± 33 mL/s. The flow was associated with the anal diameter (r = 0.84) but not with the rectoanal pressure gradient (r = 0.14). Volume-pressure loops have a tremendous impact on the understanding of cardiopulmonary pathophysiology. Future studies will shed light on potential clinical impact in defecatory pathophysiology.

Faecal incontinence in adults

Faecal incontinence, which is defined by the unintentional loss of solid or liquid stool, has a worldwide prevalence of ≤7% in community-dwelling adults and can markedly impair quality of life. Nonetheless, many patients might not volunteer the symptom owing to embarrassment. Bowel disturbances, particularly diarrhoea, anal sphincter trauma (obstetrical injury or previous surgery), rectal urgency and burden of chronic illness are the main risk factors for faecal incontinence; others include neurological disorders, inflammatory bowel disease and pelvic floor anatomical disturbances. Faecal incontinence is classified by its type (urge, passive or combined), aetiology (anorectal disturbance, bowel symptoms or both) and severity, which is derived from the frequency, volume, consistency and nature (urge or passive) of stool leakage. Guided by the clinical features, diagnostic tests and therapies are implemented stepwise. When simple measures (for example, bowel modifiers such as fibre supplements, laxatives and anti-diarrhoeal agents) fail, anorectal manometry and other tests (endoanal imaging, defecography, rectal compliance and sensation, and anal neurophysiological tests) are performed as necessary. Non-surgical options (diet and lifestyle modification, behavioural measures, including biofeedback therapy, pharmacotherapy for constipation or diarrhoea, and anal or vaginal barrier devices) are often effective, especially in patients with mild faecal incontinence. Thereafter, perianal bulking agents, sacral neuromodulation and other surgeries may be considered when necessary.

Feasibility study of defecation studied with a wireless Fecobionics probe in normal subjects

Several technologies have been developed for assessing anorectal function including the act of defecation. We used a new prototype of the Fecobionics technology, a multi-sensor simulated feces, to visualize defecatory patterns and introduced new metrics for anorectal physiology assessment in normal subjects. Fourteen subjects with normal fecal incontinence and constipation questionnaire scores were studied. The 10-cm-long Fecobionics device provided measurements of axial pressures, orientation, bending, and shape. The Fecobionics bag was distended to the urge-to-defecate level inside rectum where after the subjects were asked to evacuate. Physiological evacuation parameters were assessed. Special attention was paid to the Fecobionics rectoanal pressure gradient (F-RAPG) during evacuation. Anorectal manometry (ARM) and balloon expulsion test (BET) were done as references. The user interface displayed the fine coordination between pressures, orientation, bending angle, and shape. The pressures showed that Fecobionics was expelled in 11.5 s (quartiles 7.5 and 18.8s), which was shorter than the subjectively reported expulsion time of the BET balloon. Six subjects did not expel the BET balloon within 2 min. The F-RAPG was 101 (79-131) cmH₂ O, whereas the ARM-RAPG was -28 (-5 to -47) cmH₂ 0 (p < 0.001). There was no association between the two RAPGs (r²  = 0.19). Fecobionics showed paradoxical contractions in one subject (7%) compared to 12 subjects with ARM (86%). Fecobionics obtained novel physiological data. Defecatory patterns and data are reported and can be used to guide larger-scale studies in normal subjects and patients with defecatory disorders. In accordance with other studies, this Fecobionics study questions the value of the ARM-RAPG.

Inadequate Rectal Pressure and Insufficient Relaxation and Abdominopelvic Coordination in Defecatory Disorders

BACKGROUND & AIMS

Diagnostic tests for defecatory disorders (DDs) asynchronously measure anorectal pressures and evacuation and show limited agreement; thus, abdominopelvic-rectoanal coordination in normal defecation and DDs is poorly characterized. We aimed to investigate anorectal pressures, anorectal and abdominal motion, and evacuation simultaneously in healthy and constipated women.

METHODS

Abdominal wall and anorectal motion, anorectal pressures, and rectal evacuation were measured simultaneously with supine magnetic resonance defecography and anorectal manometry. Evacuators were defined as those who attained at least 25% rectal evacuation. Supervised (logistic regression and random forest algorithm) and unsupervised (k-means cluster) analyses identified abdominal and anorectal variables that predicted evacuation.

RESULTS

We evaluated 28 healthy and 26 constipated women (evacuators comprised 19 healthy participants and 8 patients). Defecation was initiated by abdominal wall expansion that was coordinated with anorectal descent, increased rectal and anal pressure, and then anal relaxation and rectal evacuation. Compared with evacuators, nonevacuators had lower anal diameters during simulated defecation, rectal pressure, anorectal junction descent, and abdominopelvic-rectoanal coordination (P < .05). Unsupervised cluster analysis identified 3 clusters that were associated with evacuator status (P < .01), that is, 10 evacuators (83%), 16 evacuators (73%), and 1 evacuator (5%) in clusters 1, 2, and 3, respectively. Each cluster had distinct characteristics (eg, maximum abdominosacral distance, rectal pressure, anorectal junction descent, anal diameter) and correlates that were more (clusters 1-2) or less (cluster 3) conducive to evacuation. Cluster 2 had 16 evacuators (73%) and intermediate characteristics (eg, lower anal resting pressure and relaxation during evacuation; P < .05).

CONCLUSIONS

Women with DDs and a modest proportion of healthy women had specific patterns of anorectal dysfunction, including inadequate rectal pressurization, anal relaxation, and abdominopelvic-rectoanal coordination. These observations may guide individualized therapy for DDs in the future.

Diagnostic Strategy and Tools for Identifying Defecatory Disorders

This article reviews the indications, techniques, interpretation, strengths, and weaknesses of tests (anal manometry, anal surface electromyography, rectal balloon expulsion test, barium and MRI defecography, assessment of rectal compliance and sensation, and colonic transit) that are used diagnose defecatory disorders in constipated patients. The selection of tests and the sequence in which they are performed should be individualized to and interpreted in the context of the clinical features. Because anorectal functions are affected by age, results should be interpreted with reference to age- and sex-matched normal values for the same technique.

New developments in defecatory studies based on biomechatronics

Introduction

Defecation is a complex process that is difficult to study and analyze directly. In anorectal disease conditions, the defecation process may be disturbed, resulting in symptoms including fecal incontinence and constipation. Current state-of-the-art technology measures various aspects of anorectal function but detailed analysis is impossible because they are stand-alone tests rather than an integrated multi-dimensional test.

Objectives

The need for physiologically-relevant and easy-to-use diagnostic tests for identifying underlying mechanisms is substantial. We aimed to advance the field with integrated technology for anorectal function assessment.

Methods

We developed a simulated stool named Fecobionics that integrates several tests to assess defecation pressures, dimensions, shape, orientation and bending during evacuation. A novelty is that pressures are measured in axial direction, i.e. in the direction of the trajectory. Using this novel tool, we present new analytical methods to calculate physiologically relevant parameters during expulsion in normal human subjects.

Results

Data are reported from 28 human subjects with progressively more advanced versions of Fecobionics. A new concept utilizes the rear-front pressure (preload-afterload) diagram for computation of novel defecation indices. Fecobionics obtained physiological data that cannot be obtained with current state-of-the-art technologies.

Conclusion

Fecobionics measures well known parameters such as expulsion time and pressures as well as new metrics including defecation indices. The study suggests that Fecobionics is effective in evaluation of key defecatory parameters and well positioned as an integrated technology for assessment of anorectal function and dysfunction.

Understanding the physiology of human defaecation and disorders of continence and evacuation

The act of defaecation, although a ubiquitous human experience, requires the coordinated actions of the anorectum and colon, pelvic floor musculature, and the enteric, peripheral and central nervous systems. Defaecation is best appreciated through the description of four phases, which are, temporally and physiologically, reasonably discrete. However, given the complexity of this process, it is unsurprising that disorders of defaecation are both common and problematic; almost everyone will experience constipation at some time in their life and many will develop faecal incontinence. A detailed understanding of the normal physiology of defaecation and continence is critical to inform management of disorders of defaecation. During the past decade, there have been major advances in the investigative tools used to assess colonic and anorectal function. This Review details the current understanding of defaecation and continence. This includes an overview of the relevant anatomy and physiology, a description of the four phases of defaecation, and factors influencing defaecation (demographics, stool frequency/consistency, psychobehavioural factors, posture, circadian rhythm, dietary intake and medications). A summary of the known pathophysiology of defaecation disorders including constipation, faecal incontinence and irritable bowel syndrome is also included, as well as considerations for further research in this field.

ACG Clinical Guidelines: Management of Benign Anorectal Disorders

Benign anorectal disorders of structure and function are common in clinical practice. These guidelines summarize the preferred approach to the evaluation and management of defecation disorders, proctalgia syndromes, hemorrhoids, anal fissures, and fecal incontinence in adults and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was assessed using the Grading of Recommendations Assessment, Development and Evaluation process. When the evidence was not appropriate for Grading of Recommendations Assessment, Development and Evaluation, we used expert consensus to develop key concept statements. These guidelines should be considered as preferred but are not the only approaches to these conditions.

Consensus Definitions and Interpretation Templates for Magnetic Resonance Imaging of Defecatory Pelvic Floor Disorders: Proceedings of the Consensus Meeting of the Pelvic Floor Disorders Consortium of the American Society of Colon and Rectal Surgeons, the Society of Abdominal Radiology, the International Continence Society, the American Urogynecologic Society, the International Urogynecological Association, and the Society of Gynecologic Surgeons

The Pelvic Floor Disorders Consortium (PFDC) is a multidisciplinary organization of colorectal surgeons, urogynecologists, urologists, gynecologists, gastroenterologists, radiologists, physiotherapists, and other advanced care practitioners. Specialists from these fields are all dedicated to the diagnosis and management of patients with pelvic floor conditions, but they approach, evaluate, and treat such patients with their own unique perspectives given the differences in their respective training. The PFDC was formed to bridge gaps and enable collaboration between these specialties. The goal of the PFDC is to develop and evaluate educational programs, create clinical guidelines and algorithms, and promote high quality of care in this unique patient population. The recommendations included in this article represent the work of the PFDC Working Group on Magnetic Resonance Imaging of Pelvic Floor Disorders (members listed alphabetically in Table 1). The objective was to generate inclusive, rather than prescriptive, guidance for all practitioners, irrespective of discipline, involved in the evaluation and treatment of patients with pelvic floor disorders.

Solitary rectal ulcer syndrome (SRUS): observational case series findings on MR defecography

OBJECTIVE

Radiological findings in solitary rectal ulcer syndrome (SRUS) are well described for evacuation proctography (EP) but sparse for magnetic resonance defecography (MRD). In order to rectify this, we describe the spectrum of MRD findings in patients with histologically proven SRUS.

MATERIALS AND METHODS

MRD from twenty-eight patients (18 female; 10 males) with histologically confirmed SRUS were identified. MRD employed a 1.5-T magnet and a standardized technique with the rectal lumen filled with gel and imaged sagittally in the supine position, before, during, and after attempted rectal evacuation. A single radiologist observer with 5 years' experience in pelvic floor imaging made the anatomical and functional measurements.

RESULTS

Sixteen patients (10 female) demonstrated internal rectal intussusception and 3 patients (11%) demonstrated complete external rectal prolapse. Anterior rectoceles were noted in 12 female patients (43%). Associated anterior and middle compartment weakness (evidenced by excessive descent) was observed in 18 patients (64%). Cystocele was found in 14 patients (50%) and uterine prolapse was noted in 7 patients (25%). Enterocoeles were detected in 5 patients (18%) and peritoneocoele in 5 patients (18%). None had sigmoidocoele. Sixteen patients (57%) demonstrated delayed voiding and 13 patients (46%) incomplete voiding, suggesting defecatory dyssynergia.

CONCLUSION

MRD can identify and grade both rectal intussusception and dyssynergia in SRUS, and also depict associated anterior and/or middle compartment descent. Distinction between structural and functional findings has important therapeutic implications.

KEY POINTS

MRD can identify and grade both rectal intussusception and dyssynergia in patients with SRUS. MRD is an acceptable substitute to evacuation proctography in assessing anorectal dysfunctions when attempting to avoid ionizing radiation. SRUS influences the pelvic floor globally. MRD depicts associated anterior and/or middle compartment prolapse.

The Role of Obesity on Urinary and Anal Incontinence in women: a review

Obesity is increasing worldwide with significant healthcare implications. We searched PubMed/MEDLINE, Embase and Cochrane Library for articles registered until June 2020 to explore the relationship between obesity, urinary (UI) and anal incontinence (AI). Obesity is associated with low-grade, systemic inflammation and pro-inflammatory cytokine release, producing reactive oxygen species and oxidative stress (1). This alters collagen metabolism and, in combination with increased intraabdominal pressure, contributes to UI development. Whereas in AI, stool consistency may be a factor. Weight loss can reduce UI and should be a management focus, however effect on AI is less clear. Keywords: Obesity, Urinary incontinence, Anal incontinence.

Novel bionics developments in gastroenterology: fecobionics assessment of lower GI tract function

Biomechatronics (bionics) is an applied science that is interdisciplinary between biology and engineering (mechanical, electrical and electronics engineering). Biomechatronics covers a wide area and is probably best known in development of prosthetic limbs, vision aids, robotics and neuroscience. Although the gastrointestinal tract is difficult to study, it is particularly suited for a bionics approach as demonstrated by recent developments. Ingestible capsules that travel the tract and record physiological variables have been used in the clinic. Other examples include sacral nerve stimulators that seek to restore normal anorectal function. Recently, we developed a simulated stool termed fecobionics. It has the shape of normal stool and records a variety of parameters including pressures, bending (anorectal angle) and shape changes during colonic transit and defecation, i.e. it integrates several current tests. Fecobionics has been used to study defecation patterns in large animals as well as in humans (normal subjects and patient groups including patients with symptoms of obstructed defecation and fecal incontinence). Recently, it was applied in a canine colon model where it revealed patterns consistent with shallow waves originating from slow waves generated by the interstitial cells of Cajal. Furthermore, novel analysis such as the rear-front pressure (preload-afterload) diagram and quantification of defecation indices have been developed that enable mechanistic insight. This paper reviews the fecobionics technology and outlines perspectives for future applications.

Characterization of Patients With Obstructed Defecation and Slow Transit Constipation With a Simulated Stool

INTRODUCTION

Defecatory disorders including obstructed defecation (OD) are currently diagnosed using specialized investigations including anorectal manometry and the balloon expulsion test. Recently, we developed a simulated stool named Fecobionics that provides a novel type of pressure measurements and analysis. The aim was to study OD phenotypes compared with slow transit constipation (STC) patients and normal subjects (NS).

METHODS

Fecobionics expulsion parameters were assessed in an interventional study design. The Fecobionics device contained pressure sensors at the front, rear, and inside a bag. All constipation patients had colon transit study, defecography, anorectal manometry, and balloon expulsion test performed. The Fecobionics bag was distended in the rectum until desire-to-defecate in 26 OD compared with 8 STC patients and 10 NS. Rear-front pressures (preload-afterload parameters) and defecation indices (DIs) were compared between groups.

RESULTS

The Wexner constipation scoring system score was 13.8 ± 0.9 and 14.6 ± 1.5 in the OD and STC patients (P > 0.5). The median desire-to-defecate volume was 80 (quartiles 56-80), 60 (54-80), and 45 (23-60) mL in OD, STC, and NS, respectively (P < 0.01). The median expulsion duration was 37 (quartiles 15-120), 6 (3-11), and 11 (8-11) seconds for the 3 groups (P < 0.03). Fecobionics rear-front pressure diagrams demonstrated clockwise loops with distinct phenotype differences between OD and the other groups. Most DIs differed between OD and the other groups, especially those based on the anal afterload reflecting the nature of OD constipation. Several OD subtypes were identified.

DISCUSSION

Fecobionics obtained novel pressure phenotypes in OD patients. DIs showed pronounced differences between groups. Larger studies are needed on OD subtyping.

Translating Fecobionics Into a Technique That Addresses Clinical Needs for Objective Perineal Descent Measurements

INTRODUCTION

Perineal descent is a phenomenon associated with anorectal dysfunction. It is diagnosed by defecography but subjected to manual measurements on the images/videos and interobserver bias. Fecobionics is a simulated feces for assessing important physiological parameters during defecation. Here, we translate Fecobionics into a new method for estimation of perineal descent based on electronic signals from the embedded inertial measurement units (IMUs).

METHODS

A displacement measurement method by a combined zero-velocity update and gravity compensation algorithm from IMUs was developed. The method was verified in a robot model, which mimicked perineal descent motion.

RESULTS

The method correlated well with the reference (R = 0.9789) and had a deviation from the peak displacement (range 0.25-2.5 cm) of -0.04 ± 0.498 cm. The method was further validated in 5 human experiments with comparison to the benchmark defecography technology (R = 0.79).

DISCUSSION

The proposed technology is objective, i.e., electronic measurements rather than by fluoroscopy or MRI. The development may impact clinical practice by providing a resource-saving and objective technology for diagnosing perineal descent in the many patients suffering from anorectal disorders. The technology may also be used in colon experiments with Fecobionics and for other gastrointestinal devices containing IMUs such as ingestible capsules like the Smartpill.

Novel Bionics Assessment of Anorectal Mechanosensory Physiology

Biomechatronics (bionics) is an applied science that creates interdisciplinary bonds between biology and engineering. The lower gastrointestinal (GI) tract is difficult to study but has gained interest in recent decades from a bionics point of view. Ingestible capsules that record physiological variables during GI transit have been developed and used for detailed analysis of colon transit and motility. Recently, a simulated stool named Fecobionics was developed. It has the consistency and shape of normal stool. Fecobionics records a variety of parameters including pressures, bending, and shape changes. It has been used to study defecation patterns in large animals and humans, including patients with symptoms of obstructed defecation and fecal incontinence. Recently, it was applied in a canine colon model where it revealed patterns consistent with shallow waves originating from slow waves generated by the interstitial Cells of Cajal. Novel analysis such as the "rear-front" pressure diagram and quantification of defecation indices has been developed for Fecobionics. GI research has traditionally been based on experimental approaches. Mathematical modeling is a unique way to deal with the complexity. This paper describes the Fecobionics technology, related mechano-physiological modeling analyses, and outlines perspectives for future applications.

Seated anorectal manometry during simulated evacuation: A physiologic exercise or a new clinically useful diagnostic test?

Symptoms such as a feeling of incomplete evacuation, straining, absence of the call to stool, anal blockage, or digitation suggest the presence a functional defecation disorder. As symptoms do not distinguish between patients with and without functional defecation disorder, Rome IV criteria recommend that this disorder is diagnosed when two of three tests are positive: balloon expulsion test (BET), anorectal manometry (ARM), and defecography. However, previous studies have demonstrated that the agreement among these tests is limited. In this issue of Neurogastroenterology and Motility, Sharma et al tested the hypothesis that conducting the ARM in a seated position would increase the diagnostic accuracy of the test in discriminating between patients with normal and prolonged BET. This minireview discusses the current knowledge on the role of the techniques to diagnose defecation disorder and the potential role of the ARM in a seated position.

Assessing Anorectal Function in Constipation and Fecal Incontinence

Constipation and fecal incontinence are commonly encountered complaints in the gastrointestinal clinic. Assessment of anorectal function includes comprehensive history, rectal examination, and prospective stool diary or electronic App diary that accurately captures bowel symptoms, evaluation of severity, and quality of life of measure. Evaluation of a suspected patient with dyssynergic constipation includes anorectal manometry, balloon expulsion test, and defecography. Investigation of a suspected patient with fecal incontinence includes high-resolution anorectal manometry; anal ultrasound or MRI; and neurophysiology tests, such as translumbosacral anorectal magnetic stimulation or pudendal nerve latency. This article provides an approach to the assessment of anorectal function.

Constipation and Fecal Incontinence in the Elderly

PURPOSE OF REVIEW

To review the epidemiology, pathogenesis, clinical features, and management of primary constipation and fecal incontinence in the elderly.

RECENT FINDINGS

Among elderly people, 6.5%, 1.7%, and 1.1% have functional constipation, constipation-predominant IBS, and opioid-induced constipation. In elderly people, the number of colonic enteric neurons and smooth muscle functions is preserved; decreased cholinergic function with unopposed nitrergic relaxation may explain colonic motor dysfunction. Less physical activity or dietary fiber intake and postmenopausal hormonal therapy are risk factors for fecal incontinence in elderly people. Two thirds of patients with fecal incontinence respond to biofeedback therapy. Used in combination, loperamide and biofeedback therapy are more effective than placebo, education, and biofeedback therapy. Vaginal or anal insert devices are another option. In the elderly, constipation and fecal incontinence are common and often distressing symptoms that can often be managed by addressing bowel disturbances. Selected diagnostic tests, prescription medications, and, infrequently, surgical options should be considered when necessary.

Mechanisms, Evaluation, and Management of Chronic Constipation

With a worldwide prevalence of 15%, chronic constipation is one of the most frequent gastrointestinal diagnoses made in ambulatory medicine clinics, and is a common source cause for referrals to gastroenterologists and colorectal surgeons in the United States. Symptoms vary among patients; straining, incomplete evacuation, and a sense of anorectal blockage are just as important as decreased stool frequency. Chronic constipation is either a primary disorder (such as normal transit, slow transit, or defecatory disorders) or a secondary one (due to medications or, in rare cases, anatomic alterations). Colonic sensorimotor disturbances and pelvic floor dysfunction (such as defecatory disorders) are the most widely recognized pathogenic mechanisms. Guided by efficacy and cost, management of constipation should begin with dietary fiber supplementation and stimulant and/or osmotic laxatives, as appropriate, followed, if necessary, by intestinal secretagogues and/or prokinetic agents. Peripherally acting μ-opiate antagonists are another option for opioid-induced constipation. Anorectal tests to evaluate for defecatory disorders should be performed in patients who do not respond to over-the-counter agents. Colonic transit, followed if necessary with assessment of colonic motility with manometry and/or a barostat, can identify colonic dysmotility. Defecatory disorders often respond to biofeedback therapy. For specific patients, slow-transit constipation may necessitate a colectomy. No studies have compared inexpensive laxatives with newer drugs with different mechanisms. We review the mechanisms, evaluation, and management of chronic constipation. We discuss the importance of meticulous analyses of patient history and physical examination, advantages and disadvantages of diagnostic testing, guidance for individualized treatment, and management of medically refractory patients.

MR defecography in the assessment of anatomic and functional abnormalities in stress urinary incontinence before and after pelvic reconstruction

PURPOSE

Magnetic resonance defecography (MRD) was used to evaluate anatomic and functional pelvic floor disorders in women with stress urinary incontinence (SUI) before and after midurethral sling (MUS) intervention.

METHOD

We performed MRD in both SUI patients and continent controls. Static MR was used to describe the anatomic abnormalities in levator ani muscle and periurethral ligaments (PUL). Dynamic MR was used to depict the function of the urethra and pelvic floor. We compared the MRD parameters between the SUI patients and continent controls before surgery. For SUI patients, dynamic MR images evaluated the functional changes of the urethra and pelvic floor after surgery.

RESULTS

In SUI group, 75.8 % have PUL defects, 65.7 % discontinuity or complete loss of pubococcygeal muscle, as compared to the continent groups (p < 0.01). There was no significant difference between the perimenopausal volunteers and SUI patients in the puborectalis defection (p > 0.05). The dynamic MR showed the urethral hypermobility, functional urethra shortening, bladder neck funneling, urethra opening and cystocele were significantly associated with SUI patients (p < 0.01). Postoperative MR indicated that SUI patients after MUS had a lower risk of bladder funneling and urethral opening at the defection phase (p < 0.01), but no significant difference in urethral hypermobility or pelvic floor prolapse was seen (p>0.05).

CONCLUSIONS

MRD with high-resolution and defecation phases provides a detailed anatomic and functional evaluation of the pelvic floor in female SUI before and after pelvic reconstruction.

European society of neurogastroenterology and motility guidelines on functional constipation in adults

INTRODUCTION

Chronic constipation is a common disorder with a reported prevalence ranging from 3% to 27% in the general population. Several management strategies, including diagnostic tests, empiric treatments, and specific treatments, have been developed. Our aim was to develop European guidelines for the clinical management of constipation.

DESIGN

After a thorough review of the literature by experts in relevant fields, including gastroenterologists, surgeons, general practitioners, radiologists, and experts in gastrointestinal motility testing from various European countries, a Delphi consensus process was used to produce statements and practical algorithms for the management of chronic constipation.

KEY RESULTS

Seventy-three final statements were agreed upon after the Delphi process. The level of evidence for most statements was low or very low. A high level of evidence was agreed only for anorectal manometry as a comprehensive evaluation of anorectal function and for treatment with osmotic laxatives, especially polyethylene glycol, the prokinetic drug prucalopride, secretagogues, such as linaclotide and lubiprostone and PAMORAs for the treatment of opioid-induced constipation. However, the level of agreement between the authors was good for most statements (80% or more of the authors). The greatest disagreement was related to the surgical management of constipation.

CONCLUSIONS AND INFERENCES

European guidelines on chronic constipation, with recommendations and algorithms, were developed by experts. Despite the high level of agreement between the different experts, the level of scientific evidence for most recommendations was low, highlighting the need for future research to increase the evidence and improve treatment outcomes in these patients.

Novel Fecobionics Defecatory Function Testing

INTRODUCTION

Defecation is a complex process that can be easily disturbed. Defecatory disorders may be diagnosed using specialized investigation, including anorectal manometry (ARM) and the balloon expulsion test (BET). Recently, we developed a simulated stool named Fecobionics that integrates several tests and assesses pressures, orientation, and bending during evacuation. The aim was to evaluate the feasibility and performance of Fecobionics for assessing defecatory physiology in normal subjects.

METHODS

Physiological expulsion parameters were assessed in an interventional study design. The 10-cm-long Fecobionics probe contained pressure sensors at the front and rear and inside a bag and 2 motion processor units. The bag was distended in the rectum of 20 presumed normal subjects (15 female/5 male) until urge to defecate. ARM-BET was also performed. Three subjects used +2 minutes to evacuate BET, and 1 subject had a high fecal incontinence score. Therefore, the normal group consisted of 16 subjects (13 female/3 male aged 25-78 years).

RESULTS

All subjects reported that Fecobionics evacuation was similar to normal defecation. Fecobionics expulsion pressure signatures demonstrated 5 phases, reflecting rectal pressure, anal relaxation, and anal passage. Preload-afterload loop diagrams demonstrated clockwise contraction cycles. The expulsion duration for BET and Fecobionics was 16 ± 2 and 23 ± 5 seconds (P > 0.2), respectively. The duration of the Fecobionics and BET expulsions was associated (P < 0.001). The change in bending of Fecobionics during defecation was 40 ± 3°.

DISCUSSION

Fecobionics obtained reliable data under physiological conditions. Agreement was found for comparable variables between ARM-BET and Fecobionics but not for other variables. The study suggests that Fecobionics is safe and effective in evaluation of key defecatory parameters.

Chronic Constipation

Constipation is a common symptom that may be primary (idiopathic or functional) or associated with a number of disorders or medications. Although most constipation is self-managed by patients, 22% seek health care, mostly to primary care physicians (>50%) and gastroenterologists (14%), resulting in large expenditures for diagnostic testing and treatments. There is strong evidence that stimulant and osmotic laxatives, intestinal secretagogues, and peripherally restricted μ-opiate antagonists are effective and safe; the lattermost drugs are a major advance for managing opioid-induced constipation. Constipation that is refractory to available laxatives should be evaluated for defecatory disorders and slow-transit constipation using studies of anorectal function and colonic transit. Defecatory disorders are often responsive to biofeedback therapies, whereas slow-transit constipation may require surgical intervention in selected patients. Both efficacy and cost should guide the choice of treatment for functional constipation and opiate-induced constipation. Currently, no studies have compared inexpensive laxatives with newer drugs that work by other mechanisms.

Comparison of changes in rectal area and volume during MR evacuation proctography in healthy and constipated adults

BACKGROUND

During proctography, rectal emptying is visually estimated by the reduction in rectal area. The correlation between changes in rectal area, which is a surrogate measure of volume, is unclear. Our aims were to compare the change in rectal area and volume during magnetic resonance (MR) proctography and to compare these parameters with rectal balloon expulsion time (BET).

METHODS

In 49 healthy and 46 constipated participants, we measured BET and rectal area and volume with a software program before and after participants expelled rectal gel during proctography.

KEY RESULTS

All participants completed both tests; six healthy and 17 constipated patients had a prolonged (>60 seconds) BET. During evacuation, the reduction in rectal area and volume was lower in participants with an abnormal than a normal BET (P < 0.01). The reduction in rectal area and volume were strongly correlated (r = 0.93, P < 0.001) and equivalent for identifying participants with abnormal BET. Among participants with less evacuation, the reduction in rectal area underestimated the reduction in rectal volume. A rectocele larger than 2 cm was observed in eight of 18 (44%) participants in whom the difference between change in volume and area was ˃10% but only 14 of 77 (18%) participants in whom the difference was ≤10% (P = 0.03).

CONCLUSIONS

Measured with MR proctography, the rectal area is reasonably accurate for quantifying rectal emptying and equivalent to rectal volume for distinguishing between normal and abnormal BET. When evacuation is reduced, the change in rectal area may underestimate the change in rectal volume.

Anorectal pressures measured with high-resolution manometry in healthy people-Normal values and asymptomatic pelvic floor dysfunction

BACKGROUND

High-resolution manometry (HRM) is used to measure rectoanal pressures in defecatory disorders and fecal incontinence. This study sought to define normal values for rectoanal HRM, ascertain the effects of age and BMI on rectoanal pressures, and compare pressures in asymptomatic women with normal and prolonged balloon expulsion time (BET).

METHODS

High-resolution manometry pressures and BET were measured in 163 asymptomatic healthy participants. Women (96) and men (47) with normal BET were used to estimate normal values and the effects of age/BMI on pressures using a Medtronic 4.2-mm-diameter rectoanal catheter.

KEY RESULTS

Age is associated with lower resting pressure, higher rectal pressure during evacuation, and a higher rectoanal gradient during evacuation in women and men. In women, the BET is also inversely correlated with age while the BMI is correlated with a higher threshold volume for discomfort and a longer BET. The anal squeeze pressure increment, squeeze duration, and HPZ length are higher in men than women. The rectoanal gradient during evacuation is also lower (ie, more negative) in asymptomatic women with an abnormal than a normal BET.

CONCLUSIONS & INFERENCES

These findings provide an expanded database of normal values for anorectal HRM in men and women. Age and sex affect anal resting and squeeze pressures, respectively; rectal pressure during evacuation is also higher in older people. Less than 15% of asymptomatic people have BET >60 seconds, which is associated with manometry features of impaired evacuation.

Effects of Alfuzosin, an α1-Adrenergic Antagonist, on Anal Pressures and Bowel Habits in Women With and Without Defecatory Disorders

BACKGROUND & AIMS

Some patients with defecatory disorders (DD) have high anal pressures that may impede rectal evacuation. Alpha-1 adrenoreceptors mediate as much as 50% of anal resting pressure in humans. We performed a randomized, placebo-controlled study of the effects of alfuzosin, an alpha1-adrenergic receptor antagonist, on anal pressures alone in healthy women and also on bowel symptoms in women with DD.

METHODS

In a double-blind study performed from March 2013 through March 2017, anal pressures were evaluated before and after 36 women with DD (constipation for at least 1 year) and 36 healthy women (controls) were randomly assigned (1:1) to groups given oral alfuzosin (2.5 mg immediate release) or placebo. Thereafter, patients were randomly assigned (1:1) to groups given oral alfuzosin (10 mg extended release) or placebo each day for 2 weeks. Participants kept daily diaries of bowel symptoms for 2 weeks before (baseline) and during administration of the test articles (treatment). Weekly questionnaires recorded the overall severity of constipation symptoms, bloating, abdominal pain, nausea, and vomiting; overall satisfaction with treatment of constipation was evaluated at weeks 2 and 4. The primary endpoint was the change in the number of spontaneous (SBMs) and complete SBMs (CSBMs) between the treatment and baseline periods. We evaluated relationships between stool form, passage, and complete evacuation.

RESULTS

Alfuzosin reduced anal resting pressure by 32 ± 3 mm Hg versus 16 ± 3 mm Hg for placebo (P = .0001) and anal pressure during evacuation by 26 ± 3 mm Hg versus 16 ± 3 mm Hg for placebo, (P = .03). However, alfuzosin did not significantly increase the rectoanal gradient, SBMs or CSBMs compared with placebo. Both formulations of alfuzosin were well tolerated. Hard stools and the ease of passage during defecation accounted for 72% and 76% of the variance in the satisfaction after defecation, respectively, during baseline and treatment periods.

CONCLUSIONS

In a randomized trial, alfuzosin reduced anal pressure at rest and during simulated evacuation in healthy and constipated women, compared with placebo, but did not improve bowel symptoms in constipated women. This could be because the drug does not improve stool form or dyssynergia, which also contribute to DD. ClinicalTrials.gov number, NCT 01834729.

Comparison of 3D endoanal ultrasound and external phased array magnetic resonance imaging in the diagnosis of obstetric anal sphincter injuries

Objectives

The gold standard of postpartum anal sphincter imaging has been the 3D endoanal ultrasound (EAUS). Development of magnetic resonance imaging (MRI) has allowed anal sphincter evaluation without the use of endoanal coils. The aim of this study is to compare these two modalities in diagnosing residual sphincter lesions post obstetric anal sphincter injury (OASI).

Methods

Forty women were followed up after primary repair of OASI with both 3D EAUS and external phased array MRI. Details of the anal sphincter injury and sphincter musculature were gathered and analysed.

Results

There was a moderate interrater reliability (κ = 0.510) between the two imaging modalities in detecting sphincter lesions, with more lesions detected by MRI. There was a moderate intraclass correlation (ICC) between the circumference of the tear (κ = 0.506) and a fair ICC between the external anal sphincter thickness measurements at locations 3 and 9 on the proctologic clock face (κ = 0.320) and (κ = 0.336).

Conclusions

The results of our study indicate that the use of external phased array MRI is feasible for detecting obstetric anal sphincter lesions postpartum. This allows for imaging of the sphincter defects in centres where EAUS imaging is not available.

Key Points

• A two centre prospective study that showed external phased array MRI to be a valid imaging modality for diagnosing obstetric anal sphincter injuries.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06125-8) contains supplementary material, which is available to authorized users.

Will MRI of gastrointestinal function parallel the clinical success of cine cardiac MRI?

Cine cardiac MRI is generally accepted as the "gold-standard" for functional myocardial assessment. It only took a few years after the development of commercial MRI systems for functional cardiac imaging to be developed, with electrocardiogram (ECG)-gated cine imaging first reported in 1988. The function of the gastrointestinal (GI) tract is more complex to study compared to the heart. However, the idea of having a non-invasive tool to study the GI function that also allows the concurrent assessment of different aspects of this function has become more and more attractive in the gastroenterological field. This review summarises key literature of the last 5 years to describe the current status of MRI in respect to the evaluation of GI function, highlighting the gaps and challenges and the future prospects. As the clinical application of a new technique requires that its clinical utility is confirmed by demonstration of its ability to enable clinicians to make a diagnosis and/or predict the treatment response, this review also considers whether or not this has been achieved, and how MRI has been validated against techniques currently recognised as the gold standard in clinical practice.

Audit of the diagnosis of rectal evacuation disorders in chronic constipation

BACKGROUND

Balloon expulsion test (BET) and high-resolution anorectal manometry (HRM) are used in diagnosis of rectal evacuation disorders (REDs); their performance characteristics are suboptimal.

METHODS

We audited records of 449 consecutive patients with chronic constipation (CC). We documented anal sphincter tone and contraction, puborectalis tenderness, and perineal descent on digital rectal exam (DRE); maximum resting and squeeze pressures, and rectoanal pressure gradient on HRM; weight or time to balloon expulsion; colonic transit, and area of rectal area on radiograph (RASF). We based the diagnosis of RED on ≥2 abnormalities on both DRE and HRM, excluding results of BET, as the performance of BET is being investigated. Results of RED vs non-RED and results obtained using tbBET vs wbBET groups were compared. We used multivariate logistic regressions to identify predictors of RED using different diagnostic modalities.

KEY RESULTS

Among 449 individuals, 276 were included (74 RED and 202 non-RED). Predominant exclusions were for no HRM (n = 79) or use of low resolution anorectal manometry (n = 77). Logistic regression models for abnormal tbBET showed time >60 seconds, RASF and age-predicted RED. For tbBET, the current cutoff of 60 seconds had sensitivity of 39.0% and specificity 93.0% to diagnose RED; on the other hand, applying the cutoff at 22 seconds, the sensitivity was 77.8% and specificity 69.8%.

CONCLUSIONS & INFERENCES

The clinical diagnosis of RED in patients with CC is achieved with combination of DRE, HRM and an optimized, time-based BET. Prospective studies are necessary to confirm the proposed 22 second cutoff for tbBET.

Systematic review with meta-analysis: defecography should be a first-line diagnostic modality in patients with refractory constipation

BACKGROUND

Defecography is considered the reference standard for the assessment of pelvic floor anatomy and function in patients with a refractory evacuation disorder. However, the overlap of radiologically significant findings seen in patients with chronic constipation (CC) and healthy volunteers is poorly defined.

AIM

To systematically review rates of structural and functional abnormalities diagnosed by barium defecography and/or magnetic resonance imaging defecography (MRID) in patients with symptoms of CC and in healthy volunteers.

METHODS

Electronic searches of major databases were performed without date restrictions.

RESULTS

From a total of 1760 records identified, 175 full-text articles were assessed for eligibility. 63 studies were included providing data on outcomes of 7519 barium defecographies and 668 MRIDs in patients with CC, and 225 barium defecographies and 50 MRIDs in healthy volunteers. Pathological high-grade (Oxford III and IV) intussuscepta and large (>4 cm) rectoceles were diagnosed in 23.7% (95% CI: 16.8-31.4) and 15.9% (10.4-22.2) of patients, respectively. Enterocele and perineal descent were observed in 16.8% (12.7-21.4) and 44.4% (36.2-52.7) of patients, respectively. Barium defecography detected more intussuscepta than MRID (OR: 1.52 [1.12-2.14]; P = 0.009]). Normative data for both barium defecography and MRID structural and functional parameters were limited, particularly for MRID (only one eligible study).

CONCLUSIONS

Pathological structural abnormalities, as well as functional abnormalities, are common in patients with chronic constipation. Since structural abnormalities cannot be evaluated using nonimaging test modalities (balloon expulsion and anorectal manometry), defecography should be considered the first-line diagnostic test if resources allow.