Diagnostic accuracy study of anorectal manometry for diagnosis of dyssynergic defecation

A Practical Approach to the Diagnosis and Treatment of Abdominal Bloating and Distension

Abdominal bloating and distension are highly prevalent symptoms that can negatively impact quality of life and lead to medical consultation. Despite their prevalence, symptoms of bloating and distension pose a unique diagnostic and therapeutic challenge, as they are inherently nonspecific symptoms with a complex etiology, and no uniform diagnostic or treatment algorithm currently exists. Additionally, bloating is common among disorders of gut-brain interaction, which can be difficult to treat. This article offers a practical approach for evaluating and treating symptoms of bloating and distension through discussion of 5 common etiologies: diet, small intestinal bacterial over-growth, constipation, visceral hypersensitivity, and abdomino-phrenic dyssynergia. An effective personalized evaluation and treatment plan can be established to address symptoms of bloating and distension through consideration of these etiologies in the context of the patient's individual characteristics and presentation.

Manometric parameters, when measured with the 3-dimensional high-definition anorectal manometry probe, poorly predict prolonged balloon expulsion time

BACKGROUND

There are little data evaluating the performance of the 3-dimensional high-definition anorectal manometry (3D-HDAM) system in the diagnosis of dyssynergic defecation. Physical properties of the thicker, rigid, 3D-HDAM probe may have implications on the measurements of anorectal pressures.

AIM

Our aim was to compare 3D-HDAM to balloon expulsion test and magnetic resonance (MR) defecography.

METHODS

Consecutive constipated patients referred for anorectal function testing at the Calgary Gut Motility Centre (Calgary, Canada) between 2014 and 2019 were assessed. All patients underwent anorectal manometry with the 3D-HDAM probe, and a subset underwent BET or MR defecography. Anorectal manometric variables were compared between patients who had normal and abnormal BET.

RESULTS

Over the study period, 81 patients underwent both 3D-HDAM and BET for symptoms of constipation. 52 patients expelled the balloon within 3 minutes. Patients with abnormal BET had significantly lower rectoanal pressure differential (RAPD) (-61 vs. -31 mmHg for normal BET, p = 0.03) and defecation index (0.29 vs. 0.56, p = 0.03). On logistic regression analysis, RAPD (OR: 0.99, 95% CI: 0.97-0.99, p = 0.03) remained a negative predictor of abnormal BET. On ROC analysis, RAPD had an AUC of 0.65. There was good agreement between dyssynergic patterns on 3D-HDAM and defecographic evidence of dyssynergia (sensitivity 80%, specificity 90%, PLR 9, NLR 0.22, accuracy 85%).

CONCLUSIONS

Manometric parameters, when measured with the 3D-HDAM probe, poorly predict prolonged balloon expulsion time. RAPD remains the best predictor of prolonged balloon expulsion time. The 3D-HDAM probe may not be the ideal tool to diagnose functional defecatory disorders.

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.

Evaluation of Anorectal Function in Perianal Crohn's Disease: A Pilot Study

BACKGROUND

Perianal Crohn's disease is a disabling condition, with little known about anorectal function in healed/inactive perianal Crohn's disease; Aim: To evaluate anorectal function in a cohort of patients with treated/healed perianal Crohn's disease; Methods: Prospective cohort study, including high-resolution anorectal manometry, balloon expulsion test, and 3D-endoanal ultrasound in all patients; Results: Of the 16 patients studied (mean age ± SD, 42 ± 13 years), 12 (75%) were men. A laceration of the internal anal sphincter and/or anal scarring was seen in nine (56%) patients; there was no laceration of the external anal sphincter. Five (56%) of these nine patients had never experienced faecal incontinence. All had normal anal resting and squeeze pressures. Manometry suggested dyssynergia in 11 (69%) patients, with only one (6%) fulfilling the criteria for obstructed defecation. Hyposensitivity for at least one sensory parameter was seen in 11 (69%) patients and hypersensitivity in five (31%) patients; Conclusions: This study detected sphincter abnormalities in more than half of patients, many of whom were asymptomatic. Alterations in rectal sensation were frequently seen, more commonly with rectal hyposensitivity.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03819257).

Non-drug therapies for the management of chronic constipation in adults: the CapaCiTY research programme including three RCTs

Background

Chronic constipation affects 1–2% of adults and significantly affects quality of life. Beyond the use of laxatives and other basic measures, there is uncertainty about management, including the value of specialist investigations, equipment-intensive therapies using biofeedback, transanal irrigation and surgery.

Objectives

(1) To determine whether or not standardised specialist-led habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback is more clinically effective than standardised specialist-led habit training alone, and whether or not outcomes of such specialist-led interventions are improved by stratification to habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback or habit training alone based on prior knowledge of anorectal and colonic pathophysiology using standardised radiophysiological investigations; (2) to compare the impact of transanal irrigation initiated with low-volume and high-volume systems on patient disease-specific quality of life; and (3) to determine the clinical efficacy of laparoscopic ventral mesh rectopexy compared with controls at short-term follow-up.

Design

The Chronic Constipation Treatment Pathway (CapaCiTY) research programme was a programme of national recruitment with a standardised methodological framework (i.e. eligibility, baseline phenotyping and standardised outcomes) for three randomised trials: a parallel three-group trial, permitting two randomised comparisons (CapaCiTY trial 1), a parallel two-group trial (CapaCiTY trial 2) and a stepped-wedge (individual-level) three-group trial (CapaCiTY trial 3).

Setting

Specialist hospital centres across England, with a mix of urban and rural referral bases.

Participants

The main inclusion criteria were as follows: age 18–70 years, participant self-reported problematic constipation, symptom onset > 6 months before recruitment, symptoms meeting the American College of Gastroenterology’s constipation definition and constipation that failed treatment to a minimum basic standard. The main exclusion criteria were secondary constipation and previous experience of study interventions.

Interventions

CapaCiTY trial 1: group 1 – standardised specialist-led habit training alone (n = 68); group 2 – standardised specialist-led habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback (n = 68); and group 3 – standardised radiophysiological investigations-guided treatment (n = 46) (allocation ratio 3 : 3 : 2, respectively). CapaCiTY trial 2: transanal irrigation initiated with low-volume (group 1, n = 30) or high-volume (group 2, n = 35) systems (allocation ratio 1 : 1). CapaCiTY trial 3: laparoscopic ventral mesh rectopexy performed immediately (n = 9) and after 12 weeks’ (n = 10) and after 24 weeks’ (n = 9) waiting time (allocation ratio 1 : 1 : 1, respectively).

Main outcome measures

The main outcome measures were standardised outcomes for all three trials. The primary clinical outcome was mean change in Patient Assessment of Constipation Quality of Life score at the 6-month, 3-month or 24-week follow-up. The secondary clinical outcomes were a range of validated disease-specific and psychological scoring instrument scores. For cost-effectiveness, quality-adjusted life-year estimates were determined from individual participant-level cost data and EuroQol-5 Dimensions, five-level version, data. Participant experience was investigated through interviews and qualitative analysis.

Results

A total of 275 participants were recruited. Baseline phenotyping demonstrated high levels of symptom burden and psychological morbidity. CapaCiTY trial 1: all interventions (standardised specialist-led habit training alone, standardised specialist-led habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback and standardised radiophysiological investigations-guided habit training alone or habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback) led to similar reductions in the Patient Assessment of Constipation Quality of Life score (approximately –0.8 points), with no statistically significant difference between habit training alone and habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback (–0.03 points, 95% confidence interval –0.33 to 0.27 points; p = 0.8445) or between standardised radiophysiological investigations and no standardised radiophysiological investigations (0.22 points, 95% confidence interval –0.11 to 0.55 points; p = 0.1871). Secondary outcomes reflected similar levels of benefit for all interventions. There was no evidence of greater cost-effectiveness of habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback or stratification by standardised radiophysiological investigations compared with habit training alone (with the probability that habit training alone is cost-effective at a willingness-to-pay threshold of £30,000 per quality-adjusted life-year gain; p = 0.83). Participants reported mixed experiences and similar satisfaction in all groups in the qualitative interviews. CapaCiTY trial 2: at 3 months, there was a modest reduction in the Patient Assessment of Constipation Quality of Life score, from a mean of 2.4 to 2.2 points (i.e. a reduction of 0.2 points), in the low-volume transanal irrigation group compared with a larger mean reduction of 0.6 points in the high-volume transanal irrigation group (difference –0.37 points, 95% confidence interval –0.89 to 0.15 points). The majority of participants preferred high-volume transanal irrigation, with substantial crossover to high-volume transanal irrigation during follow-up. Compared with low-volume transanal irrigation, high-volume transanal irrigation had similar costs (median difference –£8, 95% confidence interval –£240 to £221) and resulted in significantly higher quality of life (0.093 quality-adjusted life-years, 95% confidence interval 0.016 to 0.175 quality-adjusted life-years). CapaCiTY trial 3: laparoscopic ventral mesh rectopexy resulted in a substantial short-term mean reduction in the Patient Assessment of Constipation Quality of Life score (–1.09 points, 95% confidence interval –1.76 to –0.41 points) and beneficial changes in all other outcomes; however, significant increases in cost (£5012, 95% confidence interval £4446 to £5322) resulted in only modest increases in quality of life (0.043 quality-adjusted life-years, 95% confidence interval –0.005 to 0.093 quality-adjusted life-years), with an incremental cost-effectiveness ratio of £115,512 per quality-adjusted life-year.

Conclusions

Excluding poor recruitment and underpowering of clinical effectiveness analyses, several themes emerge: (1) all interventions studied have beneficial effects on symptoms and disease-specific quality of life in the short term; (2) a simpler, cheaper approach to nurse-led behavioural interventions appears to be at least as clinically effective as and more cost-effective than more complex and invasive approaches (including prior investigation); (3) high-volume transanal irrigation is preferred by participants and has better clinical effectiveness than low-volume transanal irrigation systems; and (4) laparoscopic ventral mesh rectopexy in highly selected participants confers a very significant short-term reduction in symptoms, with low levels of harm but little effect on general quality of life.

Limitations

All three trials significantly under-recruited [CapaCiTY trial 1, n = 182 (target 394); CapaCiTY trial 2, n = 65 (target 300); and CapaCiTY trial 3, n = 28 (target 114)]. The numbers analysed were further limited by loss before primary outcome.

Trial registration

Current Controlled Trials ISRCTN11791740, ISRCTN11093872 and ISRCTN11747152.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 14. See the NIHR Journals Library website for further project information.

Anorectal manometry to diagnose dyssynergic defecation: Systematic review and meta-analysis of diagnostic test accuracy

BACKGROUND

Chronic constipation is a common condition, and dyssynergic defecation underlies up to 40% of cases. Anorectal manometry is recommended to assess for dyssynergic defecation among chronically constipated patients but remains poorly standardized. We aimed to evaluate the diagnostic accuracy of anorectal manometry and determine optimal testing parameters.

METHODS

We performed a systematic review with meta-analysis of diagnostic test accuracy including cohort studies of chronically constipated patients and case-control studies of patients with dyssynergic defecation or healthy controls. Meta-analysis was performed to determine summary sensitivity, specificity, and area under the curve (AUC) with 95% confidence intervals (CI).

KEY RESULTS

A total of 15 studies comprising 2140 patients were included. Including all studies (estimating optimal diagnostic accuracy), the AUC was 0.78 [95% CI 0.72-0.82], summary sensitivity was 79% [61%-90%], and summary specificity was 64% [44%-79%] to diagnose dyssynergic defecation. In cohort studies only (estimating real-world diagnostic accuracy), the AUC was 0.72 [0.66-0.77], summary sensitivity was 86% [64%-95%], and summary specificity was 49% [30%-68%]. Employing three consecutive simulated defecation attempts improved sensitivity to 94%. A fourth simulated defecation maneuver with air insufflation may improve accuracy. Measuring anorectal pressures to identify complex dyssynergic patterns did not improve real-world diagnostic accuracy estimates over anal pressure measurement alone. Choice of manometry system did not impact diagnostic accuracy.

CONCLUSIONS & INFERENCES

Following the current iteration of the London consensus protocol (three simulated defecation attempts measuring anal relaxation), the role of anorectal manometry in evaluating dyssynergic defecation appears limited. Future iterations of this protocol may improve diagnostic accuracy.

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.

Comparison of Anorectal Function as Measured with High-Resolution and High-Definition Anorectal Manometry

INTRODUCTION

Anorectal manometry (ARM) provides comprehensive assessment of pressure activity in the rectum and anal canal. Absolute pressure values might depend on the catheter used.

OBJECTIVE

Our aim was to compare the results obtained by different anorectal catheters in children with functional anorectal disorders.

METHODS

Children diagnosed with functional defecation disorders based on the Rome IV criteria were prospectively enrolled. ARM was performed in the supine position successively using 2 different probes in each patient in random order. Resting, squeeze pressures, and bear-down maneuver variables obtained by high-resolution (2-dimensional [2D]) and high-definition (3-dimensional [3D]) catheters were compared.

RESULTS

We prospectively included 100 children {mean age 7.5 [standard deviation (SD) ± 4.3] years; 62 boys}. Mean resting pressures were significantly higher when measured with the 3D than with the 2D catheter (71 [SD ± 19.4] vs. 65 [SD ± 20.1] mm Hg, respectively; p = 0.000). Intrarectal pressure measured by 3D and 2D catheters was similar (35 vs. 39 mm Hg, respectively; p = 0.761), but the percent of anal relaxation appeared to be higher for the 3D than for the 2D probe (12 vs. 5%, respectively; p = 0.002). Dyssynergic defecation (DD) was diagnosed in 41/71 patients (57.7%) using the 3D probe and in 51/71 children (71.8%) using the 2D probe (p = 0.044). Cohen's kappa showed only fair agreement between the catheters (κ = 0.40) in diagnosis of DD.

CONCLUSIONS

Our study demonstrated significantly different values of pressures obtained with different types of catheters. Normal ranges for conventional manometry cannot be applied to high-resolution systems, and results obtained by different types of manometry cannot be compared without adjustments (NCT02812823).

Rectal Distension Increased the Rectoanal Gradient in Patients with Normal Rectal Sensory Function

BACKGROUND

Frequent observation of abnormal manometric patterns consistent with dyssynergia in healthy volunteers has warranted the need for reassessment of the current methods to enhance the diagnostic value of anorectal manometry in functional defecatory disorders. Whether rectal distention at simulated evacuation will affect anorectal pressure profile and increase rectoanal gradient is not known.

METHODS

One hundred and eight consecutive patients with chronic constipation, 93 females, median age 53 years (interquartile range: 40-65), were studied. Simulated evacuation was performed firstly with empty balloon and subsequently after balloon distention to 50 and 100 ml. Anorectal pressures were compared. We also performed subgroup analysis in relation to outcome of balloon expulsion test (BET). In addition, we studied the effect of rectal distension on the rectoanal pressure gradient with respect to rectal sensory function.

RESULTS

Rectal balloon distension at simulated evacuation improved rectoanal gradient and decreased the rate of dyssynergia during high-resolution anorectal manometry. In subgroup analysis, the increase in rectoanal gradient and correction of dyssynergia with rectal distension was limited to the patients who had normal BET and normal rectal sensory function. Rate of anal relaxation, residual anal pressures, and rectoanal gradient were significantly different between patients with and without normal BET at 50 ml of rectal distension. Rectoanal gradient recorded only after rectal distension, along with BMI and maximum tolerable volumes, could predict BET results independently in patients with chronic constipation.

CONCLUSIONS

Rectal distension during simulated evacuation will affect the anorectal pressure profile. Increase in rectoanal gradient and correction of dyssynergia was only significant in patients with normal rectal sensory function and normal BET.

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.

Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation

BACKGROUND

Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting.

PURPOSE

This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

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.

Imaging and clinical assessment of functional defecatory disorders with emphasis on defecography

Functional defecation disorders (FDD) encompass causes of constipation associated with anorectal dysfunction, which include dyssynergia or inadequate defecatory propulsion. FDD are frequently encountered in clinical practice and may affect up to 33-50% of patients with chronic constipation. The etiology of FDD is unclear, however, it has been defined as an acquired, but subliminal behavioral disorder. Pathophysiologic mechanisms may include discoordination of rectoanal muscles, paradoxical contraction or insufficient relaxation of puborectalis and/or anal sphincter during defecation, and sluggish colonic transit. A combination of comprehensive clinical assessment, digital rectal examination and a battery of physiologic tests are needed to make an accurate diagnosis of FDD. Defecography may play a crucial role in the evaluation of FDD, especially when a balloon expulsion test (BET) and/or anorectal manometry (ARM) are equivocal or demonstrate contradictory results. In this review, we provide a thorough overview of the epidemiology, pathophysiology, diagnostic criteria, clinical and imaging evaluation, and treatment options for FDD, with an emphasis on available diagnostic imaging tools such as defecography and conventional fluoroscopic methods.

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.

Fecobionics assessment of the effect of position on defecatory efficacy in normal subjects

BACKGROUND

Defecation is a complex process and up to 25% of the population suffer from symptoms of defecatory dysfunction. For functional testing, diagnostics, and therapy of anorectal disorders, it is important to know the optimal defecation position. is The aim of this study was to evaluate defecation pressure patterns in side lying, seated and squatting defecation positions in normal subjects using a simulated stool device called Fecobionics.

METHODS

The Fecobionics expulsion parameters were assessed in an interventional study design conducted from May 29 to December 9 2019. Subjects were invited to participate in the study through advertisement at The Chinese University of Hong Kong. The Fecobionics device consisted of a core containing pressure sensors at the front (caudal end) and rear (cranial end) and a polyester-urethane bag spanning most of the core length which also contained sensors. The Fecobionics bag was distended to 50 ml in the rectum of normal subjects (no present and past symptoms of defecatory disorders, no prior abdominal surgery, medication or chronic diseases). Studies were done in side lying (left lateral recumbent position), seated (hip flexed 90°) and squatting position (hip flexed 25°). Pressure endpoints including the rear-front pressure diagram and defecation indices were compared between positions.

RESULTS

Twelve subjects (6 females/6 males, mean age 26.3 ± 2.6 [19.0-48.0] years) were included and underwent the planned procedures. The resting anal pressure for side lying and seated positions were 33.1 ± 4.1 cmH₂O and 37.1 ± 4.0 cmH₂O (p > 0.3). The anal squeeze pressure for side lying and seated positions were 98.4 ± 6.9 cmH₂O and 142.3 ± 16.4 cmH₂O (p < 0.05). The expulsion duration for the side lying, seated and squatting positions were 108.9 ± 8.3 s, 15.0 ± 2.1 s and 16.1 ± 2.9 s, respectively (p < 0.01 between lying and the two other positions). The maximum evacuation pressure for seated and squatting were 130.1 ± 12.4 cmH2O and 134.0 ± 11.1 cmH₂O (p > 0.5). Rear-front pressure diagrams and distensibility indices demonstrated distinct differences in pressure patterns between the side lying position group and the other positions.

CONCLUSIONS

The delay in expelling the Fecobionics device in the lying position was associated with dyssynergic pressure patterns on the device. Quantitative differences were not found between the seated and squatting position. Trial Registration http://www.clinicaltrials.gov Identifier: NCT03317938.

Bionic measurement of defecation in a swine model

OBJECTIVE

Fecobionics was used to assess pressures, orientation, bending, shape, and cross-sectional area (CSA) changes during defecation. This study aimed to evaluate the device feasibility and performance in swine.

APPROACH

Twelve pigs had wired or wireless Fecobionics devices inserted in the rectum. The bag was distended to simulate feces in the rectum. Fecobionics data were acquired simultaneously during the whole experiment. Six pigs were euthanized immediately after the procedure for evaluation of acute injury to anorectum (acute group). The remaining pigs lived two weeks before euthanasia for evaluation of long-term tissue damage and inflammation (chronic group). Signs of discomfort were monitored.

MAIN RESULTS

All animals tolerated the experiment well. The chronic animals showed normal behavior after the procedure. Mucosal damage, bleeding, or inflammation was not found in either group. Fecobionics was defecated 1 min 35 s-61 min 0 s (median 8 min 58 s) after insertion. The defecation lasted 0 min 20 s-4 min 25 s (median 1 min 52 s). The device was almost straight inside rectum (160°-180°) but usually bended 5°-20° during contractions. The three pressure sensors showed simultaneous and identical increase during rectal or abdominal muscle contractions, indicating the location inside rectum. During defecation, the maximum rear pressure was 114.1 ± 14.3 cmH₂O whereas the front pressure gradually decreased to 0 cmH₂O, indicating the front passed anus. CSA decreased from 1017.1 ± 191.0 mm² to 530.7 ± 46.5 mm² when the probe passed from the rectum through the anal canal.

SIGNIFICANCE

Fecobionics provides defecatory measurements under physiological conditions in pigs without inducing tissue damage.

Systematic evaluation of cough-anorectal pressure responses in health and in fecal incontinence: A high-resolution anorectal manometry study

BACKGROUND

Anorectal manometry is the most commonly performed test of anorectal function. The cough-anorectal response is frequently assessed as part of a routine manometric investigation but has not previously been the subject of detailed analysis. This study systematically examined anorectal pressure responses to cough in health and evaluated the impact of parity and symptoms of fecal incontinence (FI) on measurements.

METHODS

High-resolution anorectal manometry (HR-ARM) traces from nulliparous (n = 25) and parous (n = 25) healthy volunteers (HV: aged 41, range 18-64), and 57 parous patients with FI (age 47, range 28-72) were retrospectively reviewed. Cough-anorectal pressure responses were analyzed between groups by qualitative and quantitative approaches.

KEY RESULTS

In health, traditional anal pressure measurements ("rest" and "squeeze") were similar between nulliparous and parous women. In contrast, incremental anal-rectal pressure difference during cough significantly differed: nulliparous 42 mm Hg (95% CI: 21-64) vs. parous 6 mm Hg (-14-25), P < 0.036). This measure also differed significantly between nulliparous HVs and patients with FI (-2 mm Hg (95% CI: -15-12), P < 0.001), but not between parous HVs and FI. Qualitatively, a color-contour trace resembling a "spear" in the upper anal canal was observed uniquely in FI. Of 25 patients with normal anal function by traditional measures, cough parameters were abnormal in 52%.

CONCLUSIONS AND INFERENCES

Novel HR-ARM measures during coughing revealed differences in anal function between nulliparous and parous HV, and patients with FI, which were not detected by traditional measures. Cough-anorectal measurements may improve manometric yield, though clinical utility would require assessment by longitudinal studies.

Functional Constipation: Individualising Assessment and Treatment

Chronic constipation is one of the five most common symptoms seen by gastroenterologist. In the absence of alarm symptoms, a confident symptom-based diagnosis can often be made using the Rome criteria. Three different subtypes have been identified to date: normal transit constipation, defaecatory disorders and slow transit constipation. Differentiation between these subtypes can be made through functional testing using tests such as anorectal manometry with balloon expulsion and a radio-opaque marker test. In general, patients are initially advised to increase their fluid and fibre intake. When these general lifestyle recommendations do not improve patients' symptoms, a step-wise and add-on treatment approach should be applied. This review summarises the diagnostic criteria to differentiate functional constipation from other causes of chronic constipation. In addition, current drug treatment options, including discussion of new therapeutic targets are discussed. Further, practical treatment approaches (choice and dosing), include discussion of combination/augmentation, treatment failure (adherence/expectations), and relapse prevention are mentioned. Finally, treatment and management of pain and bloating aspects are included.

Management of Chronic Abdominal Distension and Bloating

Abdominal bloating and distension are 2 of the most commonly reported gastrointestinal symptoms. Abdominal bloating is characterized by symptoms of trapped gas, abdominal pressure, and fullness. Abdominal distension is defined as a measurable increase in abdominal girth. These symptoms frequently co-exist, although they can occur separately. Defined by Rome IV criteria, functional abdominal bloating and distension commonly coincide with other functional gastrointestinal disorders, such as functional dyspepsia, irritable bowel syndrome, and functional constipation. Abdominal bloating and distension can develop for multiple reasons, including food intolerances, a previous infection that perturbed the intestinal microbiota, disordered visceral sensation, delayed intestinal transit, or an abnormal viscero-somatic reflux. Treatment can be challenging to patients and providers-no regimen has been consistently successful. Successful treatment involves identifying the etiology, assessing severity, educating and reassuring patients, and setting expectations. Therapeutic options include dietary changes, probiotics, antibiotics, prokinetic agents, antispasmodics, neuromodulators, and biofeedback. We review the epidemiology and effects of chronic bloating and distension and pathophysiology, discuss appropriate diagnostic strategies, and assess available treatment options.

Mechanophysiological analysis of anorectal function using simulated feces in human subjects

INTRODUCTION

Defecation is a complex process that is difficult to study and analyze.

OBJECTIVES

Here, we present new analytical tools to calculate frictional force and tension during expulsion of the Fecobionics simulated stool in human subjects.

METHODS

The 12-cm-long Fecobionics device contained pressure sensors, motion processor units for measurement of orientation and bending, and impedance rings for measurement of cross-sectional areas. Eight normal subjects defecated Fecobionics. The bending angle of the device, frictional force between the device and the surrounding tissue, and the stretch tensions were calculated.

RESULTS

The bending angle and pressures changed during expulsion with the maximum pressure recorded at the rear. The averaged circumferential tension, longitudinal tension and friction force in each subject were associated with the front-rear pressure difference (r > 0.7, p < 0.005). The peak circumferential tension, longitudinal tension, and friction force immediately before expulsion of the rear were significantly higher compared to when the front entered the anal canal (F = 164.7, p < 0.005; F = 152.1, p < 0.005; F = 71.4, p < 0.005; respectively.).

CONCLUSION

This study shows that Fecobionics obtained reliable data under physiological conditions. Mechanical features such as frictional force and stretch tensions were assessable during Fecobionics expulsion.

[Recommendations for the Protocol of functional examination of the anorectal zone and disorders classification: the International Anorectal Physiology Working Group consensus and Russian real-world practice]

This manuscript summarizes consensus reached by the International Anorectal Physiology Working Group (IAPWG) for the performance, terminology used, and interpretation of anorectal function testing including anorectal manometry (focused on high-resolution manometry), the rectal sensory test, and the balloon expulsion test. Based on these measurements, a classification system for disorders of anorectal function is proposed. Aim to provide information about methods of diagnosis and new classification of functional anorectal disorders to a wide range of specialists general practitioners, therapists, gastroenterologists, coloproctologists all who face the manifestations of these diseases in everyday practice and determine the diagnostic and therapeutic algorithm. Current paper provides agreed statements of IAPWG Consensus and comments (in italics) of Russian experts on real-world practice, mainly on methodology of examination. These comments in no way intended to detract from the provisions agreed by the international group of experts. We hope that these comments will help to improve the quality of examination based on the systematization of local experience with the use of the methods discussed and the results obtained. Key recommendations: the International Anorectal Physiology Working Group protocol for the performance of anorectal function testing recommends a standardized sequence of maneuvers to test rectoanal reflexes, anal tone and contractility, rectoanal coordination, and rectal sensation. Major findings not seen in healthy controls defined by the classification are as follows: rectoanal areflexia, anal hypotension and hypocontractility, rectal hyposensitivity, and hypersensitivity. Minor and inconclusive findings that can be present in health and require additional information prior to diagnosis include anal hypertension and dyssynergia.

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.

Dyssynergic patterns of defecation in constipated adolescents and young adults with anorectal malformations

We aimed to evaluate the etiologies of constipation in patients with anorectal malformations having a good prognosis for bowel control but a high risk of constipation. We included twenty-five patients from the Odense university hospital in Denmark. Patients were subjected to colon transit time examination and high resolution anorectal manometry (HRAM). The median age was 18 (14–24) and 48% (12/25) were females. Fifty-two % (13/25) of patients were diagnosed with constipation. Types of anorectal malformation were perineal fistula (9/25), rectovestibular fistula (8/25), rectourethral bulbar fistula (5/25) and no fistula (3/25). No difference in neither total colon transit time nor segmental colon transit times were found based on the presence of constipation. Only four of the constipated patients fulfilled criteria for dyssynergic defecation with a dyssynergic pattern at HRAM and prolonged colon transit time. A Type I dyssynergic pattern was dominant in constipated patients (7/13). A Dyssynergic defecation pattern was due to isolated contraction of puborectalis muscle in 9 out of 13constipated patients. We found a dyssynergic pattern during attempted defecation in patients with anorectal malformations disregarded the presence of constipation. In the majority of constipated patients an isolated contraction of the puborectalis muscle was visualized with HRAM.

Pretest and Post-test Probabilities of Diagnoses of Rectal Evacuation Disorders Based on Symptoms, Rectal Exam, and Basic Tests: a Systematic Review

BACKGROUND & AIMS

There is controversy over the utility of symptoms, examination, and tests for diagnosis of rectal evacuation disorders (REDs) or slow-transit constipation (STC). We aimed to ascertain the pooled prevalence, sensitivity, specificity, and likelihood ratios for clinical parameters to determine pretest and post-test probabilities of diagnoses of RED and STC without RED.

METHODS

We searched the MEDLINE and PUBMED databases since 1999 for studies that used binary data to calculate sensitivity, specificity, and likelihood ratios to determine the diagnostic utility of history, symptoms, and tests for RED and STC. RED and STC were defined based on confirmation by at least 1 objective anorectal test or colonic transit test. Controls had normal test results based on the specific protocol in each study.

RESULTS

We reviewed 100 articles; 63 studies of RED and 61 studies of STC met the inclusion criteria. Among 3364 patients with chronic constipation, objective tests demonstrated RED alone, 27.2%; normal transit constipation alone, 37.2%; STC alone, 19.0%; and RED with STC, 16.6%. To diagnose RED, discriminant features were urinary symptoms (specificity, 100%; likelihood ratio, above 10; 58 patients), less than 2 findings of dyssynergia in a digital rectal exam (sensitivity, 83.2%; negative likelihood ratio, 0.2; 462 patients) and rectoanal pressure gradient below -40 mm Hg with high anal pressure during straining (specificity, 100%; likelihood ratio, above 10; 101 patients). The features most strongly associated with STC alone were call to stool (specificity, 91.5%; likelihood ratio, 10.5; 75 patients) and absence of abdominal distension, fullness, or bloating (sensitivity, 92.9%; negative likelihood ratio, 0.1; 93 patients).

CONCLUSIONS

In a systematic review, we found specific symptoms, lack of dyssynergia in a digital rectal exam, and findings on anorectal manometry to be highly informative and critical in evaluation of RED and STC.

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.

Simulated stool for assessment of anorectal physiology

Fecal continence is maintained by several mechanisms including anatomical factors, anorectal sensation, rectal compliance, stool consistency, anal muscle strength, mobility, and psychological factors. The homeostatic balance is easily disturbed, resulting in symptoms including fecal incontinence and constipation. Current technologies for assessment of anorectal function have limitations. Overlap exist between data obtained in different patient groups, and there is lack of correlation between measurements and symptoms. This review describes a novel technology named Fecobionics for assessment of anorectal physiology. Fecobionics is a simulated stool, capable of dynamic measurements of a variety of variables during defecation in a single examination. The data facilitate novel analysis of defecatory function as well as providing the foundation for modeling studies of anorectal behavior. The advanced analysis can enhance our physiological understanding of defecation and future interdisciplinary research for unraveling defecatory function, anorectal sensory-motor disorders, and symptoms. This is a step in the direction of improved diagnosis of anorectal diseases.

Dyssynergic Defecation and Anal Sphincter Disorders in Children in High-Resolution Anorectal Manometry Investigation

OBJECTIVES

Dyssynergic defecation is a common disorder in children with functional constipation (FC) because of relaxation disorders of the sphincter apparatus and intra-rectal pressure during defecation. The aim of the study was to determine frequency and type of dyssynergic defecation and to assess pressure in the anal canal poles during simulated evacuation and function of puborectalis muscle in defecation in children with FC.

METHODS

Three-dimensional (3D) high-resolution anorectal manometries (3D HRAM) were performed in 131 children with FC. In the manometric test, resting pressure measurements were assessed in 4 measuring poles of the anal canal.

RESULTS

One hundred thirty-one children ages 5 to 17 years (mean age 10.2; SD ± 3.8; median 10) were involved in the study (69 girls and 62 boys). Dyssynergic defecation was shown in 106/131 (80.9%) examined children. A statistically significant difference between the age of examined children (P < 0.02) and intrarectal pressures at the anal canal measuring points (left P < 0.009, right P < 0.005, anterior P < 0.01) was found. Correlation between the residual pressure values in lateral anal canal measurement poles and intrarectal pressure was demonstrated in all types of dyssynergy (left: r = 0.69, P < 0.0005; right: r = 0.74, P < 0.0005). In a group of 53/131 (40.5%) children, 3D HRAM showed a rectal pressure increase during simulated defecation, because of the dysfunction of the puborectalis muscle.

CONCLUSION

The increase in sphincter pressure in lateral and posterior poles in I and II types of dyssynergia and in lateral poles in other types of dyssynergia may depend on relaxation disorders of the puborectalis muscle during defecation.

Improving the utility of high-resolution manometry for the diagnosis of defecatory disorders in women with chronic constipation

BACKGROUND

We compared the utility of existing and modified versions of high-resolution manometry for diagnosing defecatory disorders (DD).

METHODS

In 64 healthy and 136 constipated women, we compared left lateral (LL) and seated manometry, and analyzed with existing (ManoView™) and new methods, for discriminating between constipated patients with normal and prolonged rectal balloon expulsion time (BET). In both positions, the rectoanal gradient (RAG) and, for the new analysis, the pressure topography pattern during evacuation were used to discriminate between constipated patients without and with DD.

KEY RESULTS

The BET was prolonged, suggestive of a DD, in 52 patients (38%). During evacuation, rectoanal pressures and the RAG were greater in the seated than the LL position (P≤.001). The new analysis identified 4 rectoanal pressure patterns. In the seated position, the BET was associated with the pattern (P=.0001), being prolonged in, respectively, 45%, 15%, 53%, and 0% of patients with minimal change, anal relaxation, paradoxical contraction, and transmission. Within each pattern, the RAG was greater (ie, less negative, P<.0001) in patients with a normal than a prolonged BET. Compared to the ManoView™ RAG in the LL position, the integrated analysis (ie, pattern and new RAG) in the LL position (P<.01) and the seated ManoView™ gradient (P=.02) were more effective for discriminating between constipated patients without and with DD.

CONCLUSIONS & INFERENCES

Anorectal HRM ideally should be performed in the more physiological seated position and analyzed by a two-tier approach, which incorporates the overall pattern followed by the rectoanal gradient. These findings reinforce the utility of manometry for diagnosing DD.

The London Classification: Improving Characterization and Classification of Anorectal Function with Anorectal Manometry

PURPOSE OF REVIEW

Objective measurement of anorectal sensorimotor function is a requisite component in the clinical evaluation of patients with intractable symptoms of anorectal dysfunction. Regrettably, the utility of the most established and widely employed investigations for such measurement (anorectal manometry (ARM), rectal sensory testing and the balloon expulsion test) has been limited by wide variations in clinical practice.

RECENT FINDINGS

This article summarizes the recently published International Anorectal Physiology Working Group (IAPWG) consensus and London Classification of anorectal disorders, together with relevant allied literature, to provide guidance on the indications for, equipment, protocol, measurement definitions and results interpretation for ARM, rectal sensory testing and the balloon expulsion test. The London Classification is a standardized method and nomenclature for description of alterations in anorectal motor and sensory function using office-based investigations, adoption of which should bring much needed harmonization of practice.

Refractory Constipation: How to Evaluate and Treat

Patients are often referred for treatment of refractory constipation that may result from uncontrolled underlying disease or ineffective treatment. This article reviews clinical testing in patients with refractory constipation, differentiating subtypes of primary chronic idiopathic constipation, and common pitfalls in assessment of refractory chronic constipation. The constipation may also be refractory because of significant associated diseases affecting the colon and resulting in slow transit constipation. The choice of therapy is best guided by the subtype. Management of refractory constipation requires correct diagnosis and individualized treatment, which may rarely include conservative surgery (loop ileostomy).

Association between opioid usage and rectal dysfunction in constipation: A cross-sectional study of 2754 patients

BACKGROUND

Opioid use has reached epidemic proportions. In contrast to the known effect of opioids on gut transit, the effect on rectal sensorimotor function has not been comprehensively investigated.

METHODS

Cross-sectional (hypothesis-generating) study of anorectal physiology studies in 2754 adult patients referred to a tertiary unit (2004-2016) for investigation of functional constipation (defined by "derived" Rome IV core criteria). Statistical associations between opioid usage, symptoms, and anorectal physiological variables were investigated. Opioids were sub-classified as prescriptions for mild-moderate or moderate-severe pain.

KEY RESULTS

A total of 2354 patients (85.5%) were classified as non-opioid users, 162 (5.9%) as opioid users for mild-moderate pain, and 238 (8.6%) for moderate-severe pain. Opioids for moderate-severe pain were associated with increased symptomatic severity (Cleveland Clinic constipation score 18.5 vs 15.1; mean difference 2.9 [95%-CI 2.3-3.6]; P < .001), rectal hyposensitivity (odds ratio 1.74 [95%-CI 1.23-2.46]; P = .002), functional evacuation disorders (odds ratio 1.73 [95%-CI 1.28-2.34]; P < .001), and delayed whole-gut transit (odds ratio 1.68 [95%-CI 1.19-2.37]; P = .003). Differences in anorectal variables between opioid users for mild-moderate pain and non-opioid users were not statistically significant. Hierarchical opioid use (non vs mild-moderate vs moderate-severe) was associated with decreasing proportions of patients with no physiological abnormality on testing (40.2% vs 38.1% vs 29.2%) and increasing proportions with both delayed whole-gut transit and rectal sensorimotor dysfunction (16.6% vs 17.5% vs 28.5%).

CONCLUSIONS AND INFERENCES

Opioid use is over-represented in patients referred for investigation of constipation. Opioids for moderate-severe pain are associated with rectal sensorimotor abnormalities. Further studies are required to determine whether this association indicates causation.

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.

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.

The international anorectal physiology working group (IAPWG) recommendations: Standardized testing protocol and the London classification for disorders of anorectal function

BACKGROUND

This manuscript summarizes consensus reached by the International Anorectal Physiology Working Group (IAPWG) for the performance, terminology used, and interpretation of anorectal function testing including anorectal manometry (focused on high-resolution manometry), the rectal sensory test, and the balloon expulsion test. Based on these measurements, a classification system for disorders of anorectal function is proposed.

METHODS

Twenty-nine working group members (clinicians/academics in the field of gastroenterology, coloproctology, and gastrointestinal physiology) were invited to six face-to-face and three remote meetings to derive consensus between 2014 and 2018.

KEY RECOMMENDATIONS

The IAPWG protocol for the performance of anorectal function testing recommends a standardized sequence of maneuvers to test rectoanal reflexes, anal tone and contractility, rectoanal coordination, and rectal sensation. Major findings not seen in healthy controls defined by the classification are as follows: rectoanal areflexia, anal hypotension and hypocontractility, rectal hyposensitivity, and hypersensitivity. Minor and inconclusive findings that can be present in health and require additional information prior to diagnosis include anal hypertension and dyssynergia.

CONCLUSIONS AND INFERENCES

This framework introduces the IAPWG protocol and the London classification for disorders of anorectal function based on objective physiological measurement. The use of a common language to describe results of diagnostic tests, standard operating procedures, and a consensus classification system is designed to bring much-needed standardization to these techniques.

Poststroke Constipation Is Associated With Impaired Rectal Sensation

OBJECTIVES

Constipation is prevalent in individuals after stroke. However, the pathophysiological mechanisms of poststroke constipation remain unclear. This study was designed (i) to investigate the difference in anorectal motility and rectal sensation among stroke patients with constipation, stroke patients without constipation, and healthy controls (HC), (ii) to evaluate the impact of stroke sites on constipation and rectal sensation, (iii) to explore the role of autonomic functions, and (iv) to determine the independent risk factors for poststroke constipation.

METHODS

Seventy-one stroke patients and 24 HC were recruited. General information, clinical characteristics, and relevant questionnaires were collected. Meanwhile, an anorectal manometry test was performed to assess functions of anorectal motility and rectal sensation, and an electrocardiogram was recorded to evaluate autonomic functions.

RESULTS

(i) Constipation patients exhibited increased rectal sensation thresholds, compared with patients without constipation or HC (P < 0.001). Almost no difference was detected in anorectal motility parameters among 3 groups. Constipation-associated clinical characteristics, such as spontaneous bowel movements, were weakly or moderately correlated with rectal sensation thresholds (P < 0.05 to P < 0.001 for various parameters). (ii) Patients with brainstem lesions had increased prevalence of constipation and first sensation threshold, compared with patients without brainstem lesions (P = 0.045, P = 0.025, respectively). (iii) There was a weak positive correlation between sympathetic activity and stroke severity and a weak negative one between vagal activity and stroke severity. Rectal sensation thresholds were positively and weakly correlated with sympathetic activity but negatively with vagal activity. (iv) The desire of defecation threshold and the physical activity were independent risk factors for poststroke constipation (P = 0.043, P = 0.025, respectively).

DISCUSSION

Poststroke constipation is characterized by elevated thresholds for rectal sensation, rather than altered anorectal motility. Patients with brainstem lesions are predisposed to constipation possibly because of the disruption of afferent pathway from the rectum to the brain. Moreover, the desire of defecation threshold and the physical activity level are factors independently associated with poststroke constipation.

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.

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.

Three-dimensional high-resolution anorectal manometry can predict response to biofeedback therapy in defecation disorders

PURPOSE

Biofeedback therapy (BT) is a simple and effective technique for managing outlet constipation and fecal incontinence. Several clinical factors are known to predict BT response, but a 50% failure rate persists. Better selection of BT responsive patients is required. We aimed to determine whether the defecation disorder type per high-resolution manometry (HRM) was predictive of BT response.

METHODS

We analyzed clinical, manometric, and ultrasound endoscopic data from patients who underwent BT in our department between January 2015 and January 2016. Patients were classified into four groups per the following defecation disorder classification criteria: rectal pressure > 40 mmHg and anal paradoxical contraction (type I); rectal pressure < 40 mmHg and anal paradoxical contraction (type II); rectal pressure > 40 mmHg and incomplete anal relaxation (type III); and rectal pressure < 40 mmHg and incomplete anal relaxation (type IV). An experienced single operator conducted ten weekly 20-min sessions. Efficacy was evaluated with the visual analog scale.

RESULTS

Of 92 patients, 47 (50.5%) responded to BT. Type IV and type II defecation disorders were predictive of success (p = 0.03) (OR = 5.03 [1.02; 24.92]) and failure (p = 0.05) (OR = 0.41 [0.17; 0.99]), respectively. The KESS score severity before BT (p = 0.03) (OR = 0.9 [0.81; 0.99]) was also predictive of failure.

CONCLUSION

The manometry types identified according to the defecation disorder classification criteria were predictive of BT response. Our data confirm the role of three-dimensional HRM in the therapeutic management of anorectal functional disorders.

High-resolution Anorectal Manometry in the Diagnosis of Functional Defecation Disorder in Patients With Functional Constipation: A Retrospective Cohort Study

Background/Aims

High-resolution anorectal manometry (HRAM) has been considered a first-line diagnostic tool for functional defecation disorder. However, clinical studies on HRAM used in constipation patients are very limited and few studies have reported the characteristics of anorectal pressure in Chinese patients. The aim of this study is to investigate the characteristics of motility data in a cohort of Chinese patients with functional constipation.

Methods

A total of 82 consecutive patients with functional constipation who underwent a standardized HRAM were retrospectively enrolled in this study. The functional defecation disorder was classified into Rao’s types.

Results

The mean age of 82 patients was 51 years (range, 16–83 years). Indications for anorectal manometry were functional constipation for all patients. The mean resting pressure was 69.2 ± 21.2 mmHg (range, 24.5–126.9 mmHg). The mean maximum squeezing pressure was 198.4 ± 75.6 mmHg (range, 54.2–476.9 mmHg). The mean length of the anal high pressure zone was 3.4 ± 1.0 cm (range, 0.6–4.9 cm). Sixty (73.2%) patients were diagnosed as functional defecation disorder. In attempted defecation, type I was most common (n = 24), followed by type II (n = 12), type III (n = 11), and type IV (n = 13) that were present on HRAM according to Rao’s classification. In all 60 patients with functional defecation disorder, 37 were women and 23 were men. Men were significantly more likely than women to have functional defecation disorder (92.0% vs 64.9%, P = 0.014).

Conclusion

HRAM could be used as a test for the diagnosis of functional defecation disorder and functional defecation disorder is common in Chinese patients with functional constipation.

Anorectal physiology in health: A randomized trial to determine the optimum catheter for the balloon expulsion test

BACKGROUND

Anorectal manometry (ARM) and balloon expulsion test (BET) are pivotal in investigation of anorectal disorders. There is controversy, however, about normal values and optimum methodology for performing these tests. Our aims were to compare BET using three different balloons and to establish normal values for ARM and BET in health.

METHODS

Forty-four female healthy subjects (mean age 56 ± 12 years) underwent ARM, followed by BET which was performed in a private toilet using three different catheters (party balloon, Foley catheter and a commercially available catheter) in a single-blinded randomized order. Outcome measures were time to balloon expulsion and comprehensive measures of anal sphincter function, the push maneuver and rectal sensation.

KEY RESULTS

The Foley catheter took longer to expel compared to both party and commercial balloons (both pairwise P < 0.001) with a wider distribution of results (P < 0.001). Ten of 40 healthy subjects could not expel the Foley catheter within 120 seconds. On ARM, older age was associated with lower resting anal sphincter pressure (ρ = -0.3, P = 0.05) and lower anal squeeze pressure (ρ = -0.3, P = 0.05). Having at least one vaginal delivery (compared to none) was associated with lower anal squeeze pressures (P = 0.03) and a smaller difference between cough and squeeze pressures (P = 0.03).

CONCLUSIONS & INFERENCES

A commercial balloon exhibited superior results in vivo compared to the Foley catheter without the concerns of latex allergy and quality control present with the use of a party balloon. Normal values for high-resolution water-perfused manometry have been established and an effect seen for age and parity.

Three-dimensional high-resolution anorectal manometry in functional anorectal disorders: results from a large observational cohort study

BACKGROUND

The aim of the study was to describe the results of 3D high-resolution anorectal manometry (3DHRAM) in a large cohort of patients with functional anorectal disorders.

METHODS

In this single-center retrospective study, all consecutive patients referred for investigation of fecal incontinence (FI) or dyssynergic defecation (DD) underwent 3DHRAM. The parameters analyzed were usual manometric data, repartition of dyssynergic patterns, and the prevalence of a new "muscular subtype classification" underlying dyssynergia, anal sphincter defects, and pelvic floor disorders.

RESULTS

Final analyses were performed in 1477 patients with a mean age 54 ± 16 years; 825 patients suffered from DD, and 652 patients suffered from FI. Among these patients, 86% met the diagnostic criteria for dyssynergia. Type II dyssynergia was the most frequently observed (56%) in women and men suffering from FI and in women with DD. Type I was the most frequently observed in men with DD (49%). Regarding the muscle type subgroups, combined puborectalis muscle involvement with an external anal sphincter profile was the most frequently observed. The global prevalence of rectal intussusception and excessive perineal descent were 12% and 21%, respectively. Type III dyssynergia was more frequently associated with pelvic floor disorders than were other types of dyssynergia (p < 0.001).

CONCLUSION

This large cohort study provides reference values for 3DHRAM in patients with functional anorectal disorders. Further studies are necessary to assess the prevalence of pelvic floor disorders in healthy volunteers and to develop new scores and classifications including all of these new parameters.

Functional anal canal length measurement using high-resolution anorectal manometry to investigate anal sphincter dysfunction in patients with fecal incontinence or constipation

BACKGROUND

Using high-resolution anorectal manometry, we aimed to evaluate the: (a) optimal threshold to measure functional anal canal length (FACL) with intra- and inter-observer variability; (b) relationship between abnormal FACL and other phenotypic findings; and (c) utility of FACL measurement to discriminate between healthy volunteers (HV) and patients with fecal incontinence (FI) or chronic constipation (CC).

METHODS

Consecutive patients referred for investigation of FI or CC in isolation were included. FACL was calculated at 5, 10, 20, 30, and 50 mm Hg above rectal pressure. 5th-95th percentile in HV defined limits of normality.

KEY RESULTS

FACL was analyzed in 192 patients with FI (154 females), 204 patients with CC (175 females), and 134 HV (101 females). The optimal threshold for measurement of FACL was 20 mm Hg. Using this threshold, observer reproducibility was very high (ICC 0.99, P < 0.0001). FACL was shorter in females with FI and longer in females with CC compared to HV (2.3 vs 2.9 cm; and 3.4 cm vs 2.9 cm; both P < 0.0001). Twenty percent of females and 13% males with FI had a short FACL, associated with older age, anal hypotonia or hypocontractility, and a atrophic internal anal sphincter. However, abnormal FACL in isolation was only found in 1/190 FI (0.5%) and 2/201 CC (1%) patients; all other patients had other abnormal manometric findings.

CONCLUSIONS AND INFERENCES

Considering overlap with other routinely evaluated manometric parameters, FACL measurement does not provide additional information in the diagnostic assessment of FI or CC.