The use of colonic and anorectal high-resolution manometry and its place in clinical work and in research

London Protocol under water-perfused HRM in a healthy population, towards novel 3D manometric parameters in an evaluation of anorectal functional disorders

BACKGROUND/AIM

London Protocol (LP) and Classification allied to high-resolution manometry (HRM) technological evolution has updated and enhanced the diagnostic armamentarium in anorectal disorders. This study aims to evaluate LP reproducibility under water-perfused HRM, provide normal data and new parameters based on 3D and healthy comparison studies under perfusional HRM.

METHODS

Fifty healthy (25 F) underwent water-perfused 36 channel HRM based on LP at resting, squeeze, cough, push, and rectal sensory. Additional 3D manometric parameters were: pressure-volume (PV) 104mmHg2.cm (resting, short and long squeeze, cough); highest and lowest pressure asymmetry (resting, short squeeze, and cough). Complementary parameters (CP) were: resting (mean pressure, functional anal canal length); short squeeze (mean and maximum absolute squeeze pressure), endurance (fatigue rate, fatigue rate index, capacity to sustain); cough (anorectal gradient pressure); push (rectum-anal gradient pressure, anal canal relaxation percent); recto-anal inhibitory reflex (anal canal relaxation percent).

RESULTS

No difference to genders: resting (LP, CP, and 3D); short squeeze (highest pressure asymmetry); endurance (CP); cough (CP, highest and lowest pressure asymmetry); push (gradient pressure); rectal sensory. Higher pressure in men: short squeeze (maximum incremental, absolute, and mean pressure, PV, lowest pressure asymmetry); long squeeze (PV); cough (anal canal and rectum maximum pressure, anal canal PV); push (anal canal and rectum maximum pressure). Anal canal relaxation was higher in women (push).

CONCLUSIONS

LP reproducibility is feasible under water-perfused HRM, and comparative studies could bring similarity to dataset expansion. Novel 3D parameters need further studies with healthy and larger data to be validated and for disease comparisons.

KEY POINTS

• London Protocol and Classification allied with the technological evolution of HRM (software and probes) has refined the diagnostic armamentarium in anorectal disorders. • Novel 3D and deepening the analysis of manometric parameters before the London Classification as a contributory diagnostic tool. • Comparison of healthy volunteers according to the London Protocol under a perfusional high-resolution system could establish equivalence points.

Diagnostic and therapeutic approach to children with chronic refractory constipation: Consensus report by the SIGENP motility working group

Constipation is a common problem in children, accounting for about 3% of all primary care visits and up to 25% of referrals to paediatric gastroenterologists. Although polyethylene glycol often proves effective, most children require prolonged treatment and about 50% of them have at least one relapse within the first 5 years after initial recovery. When conventional treatment fails, children are considered to have refractory constipation. Children with refractory constipation deserve specialist management and guidance. Over the last decades, there has been a remarkable increase in our knowledge of normal and abnormal colonic and anorectal motility in children, and a number of different techniques to measure transit and motility have been developed. The present review analyses the possible diagnostic investigations for children with refractory constipation, focusing on their actual indications and their utility in clinical practice. Moreover, we have also analytically reviewed medical and surgical therapeutic options, which should be considered in selected patients in order to achieve the best clinical outcome.

Current and future perspectives on the utility of provocative tests of anal sphincter function: A state-of-the-art summary

BACKGROUND

The maintenance of fecal continence depends upon coordinated interactions between the pelvic floor, anorectum, and anal sphincter complex orchestrated by central and peripheral neural activities. The current techniques to objectively measure anorectal function rely on fixed diameter catheters placed inside the anal canal with a rectal balloon to obtain measurements of anal resting and squeeze function, and rectal compliance. Until recently it had not been possible to measure the distensibility of the anal canal, or in other words its ability to resist opening against an increasing pressure, which has been proposed as the main determinant of a biological sphincter's function. Anal acoustic reflectometry (AAR) and the functional lumen imaging probe (FLIP) are two novel, provocative techniques that dynamically assess the anal sphincter complex under volume-controlled distension. In doing so, both provide information on the viscoelastic properties of the anal canal and offer new insights into its function.

PURPOSE

This review details the current and potential future applications of AAR and FLIP and highlights the unanswered questions relevant to these new technologies.

The colonic motility and classification of patients with slow transit constipation by high-resolution colonic manometry

BACKGROUND

This study aimed to evaluate the colonic motility of slow transit constipation (STC) patients using high-resolution colonic manometry (HRCM) and classify the patients' subtypes to instruct treatment based on HRCM characteristics.

METHODS

This study enrolled one hundred and twenty-six STC patients and 35 volunteers (healthy controls, HCs). Ambulatory HRCM was performed in all participants by placing a 36-sensor water-perfused probe up to the cecum. Quantitative and qualitative manometric analysis was conducted in the state of rest, postprandial, during sleep, and wakefulness.

RESULTS

The occurrence rate and times of high amplitude propagated contraction (HAPC) in STC patients were lower than HCs. As for the HAPC contraction characteristics, the mean velocity was similar, contraction length, amplitude, area under the curve (AUC) of pressure wave, and duration were reduced in STC patients compared with HCs. In addition, the occurrence rate and times of low amplitude propagated contraction (LAPC) in STC patients were similar compared to HCs. There was no difference in HAPC occurrence, LAPC occurrence, and most detailed HAPC characteristics between STC patients ≤60 years and STC patients >60 years or between male STC patients and female STC patients. Based on the HRCM characteristics (including HAPC, neostigmine induced HAPC, LAPC, and waking/gastrocolic response), STC patients were classified into four types, respectively, with recommended treatment by clinical experience.

CONCLUSION

HRCM serves as a valuable tool in characterizing, classifying the pathophysiology, and guiding clinical management for STC.

Utility of postoperative anorectal manometry in children with anorectal malformation: a systematic review

Children with anorectal malformation (ARM) often continue to have disturbances in bowel function long after reconstructive surgery. Anorectal manometry may be utilized to evaluate bowel function in these children. We aimed to describe the reported protocols and manometric findings in children with ARM post-reconstructive surgery and to investigate the correlation between manometric evaluation and bowel functional outcome. PubMed, EMBASE, and Google Scholar databases were searched from 1980 to 2021. Data were reviewed and extracted independently by two authors, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Included studies were English articles reporting postoperative assessment of children (≤ 18 years) with ARM using anorectal manometry. From 128 articles obtained in the initial search, five retrospective cohort studies and one prospective study fulfilled inclusion criteria. The rectoanal inhibitory reflex and mean anal resting pressure were parameters most often reported to correlate with postoperative bowel function. The least reported parameters among the studies were high-pressure zone, rectal volume, and rectal sensation. Anorectal manometry could be an objective method providing important information for personalized management of postoperative ARM patients with bowel function issues, but lack of standardized protocols limits a comprehensive analysis of their utility.

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.

Clinical impact of the triple‐layered circular stapler for reducing the anastomotic leakage in rectal cancer surgery: Porcine model and multicenter retrospective cohort analysis

Aim

To investigate the impact of the triple‐layered circular stapler compared with the double‐layered circular stapler on anastomotic leakage after rectal cancer surgery.

Methods

The bursting pressure was compared between porcine ileocolic anastomoses created using a double‐ or triple‐layered stapler. We also retrospectively analyzed the incidence of severe anastomotic leakage in 194 patients who underwent colorectal anastomosis using a double‐ or triple‐layered circular stapler during rectal cancer resection performed in two cancer centers between January 2015 and April 2021.

Results

In the porcine model, the bursting pressure was higher in anastomoses created using the triple‐layered stapler than the double‐layered stapler (end‐to‐end anastomosis: 26.4 ± 6.2 mm Hg vs 14.5 ± 4.3 mm Hg, P = .0031; side‐to‐side anastomosis: 27.7 ± 5.0 mm Hg vs 18.0 ± 2.9 mm Hg, P = .0275). Intersectional leakage occurred in 41% and 83% of anastomoses created using the triple‐ or double‐layered stapler, respectively (P = .0821). In the clinical cohort, the double‐ and triple‐layered stapler was used in 153 and 41 patients, respectively. The incidence of anastomotic leakage was lower for anastomoses created using the triple‐layered stapler vs the double‐layered stapler (0.0% vs 5.8%, P = .0362). In multivariate analysis, the factors independently associated with a lower incidence of anastomotic leakage were female sex (odds ratio: 0.16, 95% confidence interval: 0.01‐0.90, P = .0354) and triple‐layered stapler usage (odds ratio: 0.00, 95% confidence interval: 0.00‐0.96, P = .0465).

Conclusion

Anastomoses created using a triple‐layered circular stapler had high bursting pressure, which might contribute to a lower incidence of anastomotic leakage after rectal cancer surgery.

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.

Anorectal manometry in pediatric settings: A systematic review of 227 studies

BACKGROUND

There is wide variation in the clinical use of diagnostic tools for children with chronic constipation and functional/structural fecal incontinence (CCFSFI). Anorectal manometry (ARM) is a well-recognized technique to assess the function of the anorectum.

PURPOSE

Our aim was to perform an up-to-date review on ARM in pediatric patients with CCFSFI, with specific focus on the indication of use and protocol. Variation of its use in pediatrics will be explored.

METHODS

A systematic search was conducted for empirical studies utilizing ARM with a pediatric sample. A keyword search of literature published in English before July 2018 was conducted and updated to October 2019. Data on demographics, clinical information, study aims, ARM parameters and use of sedation/anesthesia were collected.

KEY RESULTS

A total of 227 studies were included in this systematic review. The age of study participants at the time of ARM ranged from birth to 18 years. ARM was most commonly used in patients with organic conditions (65%) compared to functional constipation (41%). In almost half [108/227 (48%)] of the studies, ARM was performed awake. The ARM parameters most frequently assessed were the rectoanal inhibitory reflex, which was evaluated in 198/227 studies (87%) and the anal resting pressure [166/227 studies (73%)].

CONCLUSIONS AND INFERENCES

This systematic review has highlighted the vast variation of ARM use within pediatrics and the need to strive toward standardization and use of consensus guidelines. We anticipate this will further advance our understanding of the pathophysiological mechanisms involved in children with defecation disorders.

Assessment of Gastrointestinal Autonomic Dysfunction: Present and Future Perspectives

The autonomic nervous system delicately regulates the function of several target organs, including the gastrointestinal tract. Thus, nerve lesions or other nerve pathologies may cause autonomic dysfunction (AD). Some of the most common causes of AD are diabetes mellitus and α-synucleinopathies such as Parkinson’s disease. Widespread dysmotility throughout the gastrointestinal tract is a common finding in AD, but no commercially available method exists for direct verification of enteric dysfunction. Thus, assessing segmental enteric physiological function is recommended to aid diagnostics and guide treatment. Several established assessment methods exist, but disadvantages such as lack of standardization, exposure to radiation, advanced data interpretation, or high cost, limit their utility. Emerging methods, including high-resolution colonic manometry, 3D-transit, advanced imaging methods, analysis of gut biopsies, and microbiota, may all assist in the evaluation of gastroenteropathy related to AD. This review provides an overview of established and emerging assessment methods of physiological function within the gut and assessment methods of autonomic neuropathy outside the gut, especially in regards to clinical performance, strengths, and limitations for each method.

[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.

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

BACKGROUND

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

METHODS

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

KEY RESULTS

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

CONCLUSIONS AND INFERENCES

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

Comparison of anorectal function measured using wearable digital manometry and a high resolution manometry system

There is a need for a lower cost manometry system for assessing anorectal function in primary and secondary care settings. We developed an index finger-based system (termed "digital manometry") and tested it in healthy volunteers, patients with chronic constipation, and fecal incontinence. Anorectal pressures were measured in 16 participants with the digital manometry system and a 23-channel high-resolution anorectal manometry system. The results were compared using a Bland-Altman analysis at rest as well as during maximum squeeze and simulated defecation maneuvers. Myoelectric activity of the puborectalis muscle was also quantified simultaneously using the digital manometry system. The limits of agreement between the two methods were -7.1 ± 25.7 mmHg for anal sphincter resting pressure, 0.4 ± 23.0 mmHg for the anal sphincter pressure change during simulated defecation, -37.6 ± 50.9 mmHg for rectal pressure changes during simulated defecation, and -20.6 ± 172.6 mmHg for anal sphincter pressure during the maximum squeeze maneuver. The change in the puborectalis myoelectric activity was proportional to the anal sphincter pressure increment during a maximum squeeze maneuver (slope = 0.6, R2 = 0.4). Digital manometry provided a similar evaluation of anorectal pressures and puborectalis myoelectric activity at an order of magnitude less cost than high-resolution manometry, and with a similar level of patient comfort. Digital Manometry provides a simple, inexpensive, point of service means of assessing anorectal function in patients with chronic constipation and fecal incontinence.

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.

Anorectal manometry in children with defecation disorders BSPGHAN Motility Working Group consensus statement

Defecatory disorders in children, including chronic constipation (CC) and fecal incontinence (FI), are common conditions worldwide and have a significant impact on children, their families, and the healthcare system. Anorectal manometry (ARM) and high-resolution anorectal manometry (HRAM) are relatively novel tools for the assessment of anal sphincter function and rectal sensation and have contributed significantly to improving the understanding of the anorectum as a functional unit. ARM has been recognized as the investigation of choice for adults with symptoms of defecation disorders, including fecal incontinence (FI), evacuation difficulties, and constipation. Although it is the gold standard tool in adults, it has yet to be formally accepted as a standardized diagnostic tool in the pediatric age, with limited knowledge regarding indications, protocol, and normal values. ARM/HRAM is slowly becoming recognized among pediatricians, but given that there are currently no agreed guidelines there is a risk that will lead to diversity in practice. The British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN)-Motility Working Group (MWG) therefore has taken the opportunity to provide guidance on the use of ARM/HRAM in children with CC and/or FI.

High resolution anorectal manometry. Recommendations on russian-language terminology based on interdisciplinary consensus

The aim of the paper — is to present the results of the consensus on the terminology used to describe data of high-resolution anorectal manometry.

Methods: Online survey was conducted with the help of the public platform “Google forms” with the aim to harmonize the terms, which are used to conduct high-resolution anorectal manometry (HRAM), to agree the conformity of the proposed Russian-language terms to those used in English-language literature, and their abbreviations.

Results: According to the aim, 56 specialists of different medical specialties who perform and use the results of HRAM in clinical practice and research were invited to participate in the survey. We received 45 answers from the respondents (42.2% coloproctologists, 22.2% gastroenterologists, 15.6% surgeons, 20% — representatives of other specialties). The response rate was 80.3%. According to the survey, 95.6% of respondents supported the need for harmonization of terms. Ten out of the 11 terms reached consensus level C1 (excellent), 1 term level of consistency was C2 (moderate). 90.9% of respondents (consensus level C1) were in favor of the appropriateness of using common abbreviations. However, the proposed abbreviations of the terms used in the conduct and description of the results of the HRAM can be accepted with reservations (in 10 cases out of 11 consensus level was C2).

Conclusions: The agreed in interdisciplinary consensus terms can be approved and recommended for the use in clinical practice and when research data are published in Russian-language scientific literature.

Scientific solution to a complex problem: physiology and multidisciplinary team improve understanding and outcome in chronic constipation and faecal incontinence

PURPOSE

There is a lack of diagnostic credibility to direct focused management for children with chronic constipation (CC) and faecal incontinence (FI). The aim is to assess the impact of an innovative Children's Anorectal Physiology Service (CAPS) focusing on improving outcomes in children with CC/FI.

METHODS

Prospective data: demographics, bowel and quality of life (QoL)/risk of distress questionnaires. Diagnostics: awake high-resolution anorectal manometry (AHRAM), endoanal ultrasound and transit marker studies (TMS).

RESULTS

Total patients: 112; 66 males (59%); median 9 years (17 months to 16 years). Patient groups included: 89 (79%) had functional CC/FI; 9 (8%), Hirschsprung's disease; 12 (11%), anorectal malformations and 2 (2%), trauma. St Marks Incontinence score (SMIS) abnormal in 91 (81%) and Cleveland Constipation Score (CCS) in 101 (90%) patients. Anorectal manometry: 94 (84%) awake and 18 (17%) under anaesthesia. Play specialist input 37 (33%) patients. AHRAM abnormal 65 (58%): sphincter dysfunction 36 (32%) and altered rectal sensation: hyposensitive 22% (20/91); 21% (19/91) hypersensitive. TMS normal in 64 (57%), 17 (15%) slow transit and 27 (24%) rectal evacuatory disorder. Risk of distress in 38% and poor QoL in 55% patients which correlated with abnormal SMIS (p = 0.02). Patient/parent satisfaction improved significantly (p < 0.05).

CONCLUSIONS

Scientific investigations combined with multidisciplinary team improve patient satisfaction and reduces patient self-report illness severity. A complex problem requires a scientific solution.

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.

High-resolution colonic manometry and its clinical application in patients with colonic dysmotility: A review

The detailed process and mechanism of colonic motility are still unclear, and colonic motility disorders are associated with numerous clinical diseases. Colonic manometry is considered to the most direct means of evaluating colonic peristalsis. Colonic manometry has been studied for more than 30 years; however, the long duration of the examination, high risk of catheterization, huge amount of real-time data, strict catheter sterilization, and high cost of disposable equipment restrict its wide application in clinical practice. Recently, high-resolution colonic manometry (HRCM) has rapidly developed into a major technique for obtaining more effective information involved in the physiology and/or pathophysiology of colonic contractile activity in colonic dysmotility patients. This review focuses on colonic motility, manometry, operation, and motor patterns, and the clinical application of HRCM. Furthermore, the limitations, future directions, and potential usefulness of HRCM in the evaluation of clinical treatment effects are also discussed.

First translational consensus on terminology and definitions of colonic motility in animals and humans studied by manometric and other techniques

Alterations in colonic motility are implicated in the pathophysiology of bowel disorders, but high-resolution manometry of human colonic motor function has revealed that our knowledge of normal motor patterns is limited. Furthermore, various terminologies and definitions have been used to describe colonic motor patterns in children, adults and animals. An example is the distinction between the high-amplitude propagating contractions in humans and giant contractions in animals. Harmonized terminology and definitions are required that are applicable to the study of colonic motility performed by basic scientists and clinicians, as well as adult and paediatric gastroenterologists. As clinical studies increasingly require adequate animal models to develop and test new therapies, there is a need for rational use of terminology to describe those motor patterns that are equivalent between animals and humans. This Consensus Statement provides the first harmonized interpretation of commonly used terminology to describe colonic motor function and delineates possible similarities between motor patterns observed in animal models and humans in vitro (ex vivo) and in vivo. The consolidated terminology can be an impetus for new research that will considerably improve our understanding of colonic motor function and will facilitate the development and testing of new therapies for colonic motility disorders.

Use of high-resolution colonic manometry to establish etiology and direct treatment in patients with constipation: Case series with correlation to histology

BACKGROUND AND AIM

Different clinical treatments are available to treat patients with constipation. We aimed to study the etiology and direct treatment in a case series of patients with constipation by the use of high-resolution colonic manometry (HRCM).

METHODS

High-resolution colonic manometry was used to record the colorectal peristaltic contractions of the entire colon in patients. Based on the results of HRCM, 151 patients with constipation were classified into groups and received different clinical treatment such as a total or subtotal colectomy, local excision, or conservative treatment. Paraffin-embedded samples obtained after resection were studied using hematoxylin and eosin, as well as immunohistochemical staining.

RESULTS

All patients underwent HRCM over 24 h. Based on the amplitude, intensity, and trends in peristaltic contractions recorded by HRCM, we observed 117 patients with slow-transit constipation and 34 with functional outlet obstruction constipation. After an overall evaluation of the results of HRCM and anorectal function, 26, 23, 27, and 75 patients were treated with total colectomy, subtotal colectomy, local excision, and conservative treatment, respectively. Furthermore, histological examination of surgical samples showed vacuolar degeneration of nerve plexuses as well as of the muscularis propria, which also showed fibrosis in its outer layers in patients with constipation.

CONCLUSION

Different types of constipation showed different colonic motility patterns and morphological changes in the colonic wall. HRCM plays an important role in the diagnosis and classification of patients with constipation. Furthermore, HRCM can accurately identify the diseased colonic segments and help to choose the appropriate treatment.

Phase waves and trigger waves: emergent properties of oscillating and excitable networks in the gut

The gut is enmeshed by a number of cellular networks, but there is only a limited understanding of how these networks generate the complex patterns of activity that drive gut contractile functions. Here we review two fundamental types of cell behaviour, excitable and oscillating, and the patterns that networks of such cells generate, trigger waves and phase waves, respectively. We use both the language of biophysics and the theory of nonlinear dynamics to define these behaviours and understand how they generate patterns. Based on this we look for evidence of trigger and phase waves in the gut, including some of our recent work on the small intestine.

WATER-PERFUSED HIGH-RESOLUTION ANORECTAL MANOMETRY (HRAM-WP): THE FIRST BRAZILIAN STUDY

BACKGROUND

High resolution anorectal manometry (HRAM-WP) allows more simplified, objective, and uniform data acquisition and interpretation of the test results.

OBJECTIVE

To validate a HRAM under water perfusion (Alacer Biomédica) with a 24-channel probe and to compare the results of anorectal manometry with other systems.

METHODS

Individuals without critical evacuation disorders were selected. Patients with incontinence, anal surgery, dyssynergia or sphincter injury were excluded. The test was performed with an Alacer Biomédica 24 channel manometry system under water perfusion, with a probe configured with 6 levels of 4 radial channels, separated from each other by 0.8 mm. The mean pressures for the functional channel were determined, in states of rest (RMP), contention effort (CMP) and evacuation effort (EEMP). The pressure extension of the sphincter was also tabulated in cm. The results were compared with those available in recent literature.

RESULTS

Fifty patients were studied (20 men; 30 women). Overall, the following results were obtained: the RMP was 76.9±3.0 mmHg, the CMP was 194.2±9.4 mmHg, and EEMP was 88.2±3.7 mmHg. When classified according to the gender, for men: RMP was 72.2±3.0 mmHg, CMP was 229.5±17 mmHg, and EEMP was 91.4±7.0. For women, RMP was 79.8±4.0 mmHg, CMP was 170.7±8, and EEMP was 86.1±4.3 mmHg. The sphincter gauge extension for both genders was 3.1±0.09 cm (men 3.3±0.1; women 3.0±0.1).

DISCUSSION

Studying HRAM-WP has become much easier. Non-mobilization of the sensor causes less discomfort and artefacts with a lower assessment time. In this study, small differential values between both sexes during rest were observed, highlighting a greater containment force in men. No difference in sphincter extension was noted. The results of this study are consistent with that of existing reports and with those obtained using solid state probes.

CONCLUSION

The perfusion system yielded results similar to that of solid state systems. Further studies to evaluate parameters with respect to pelvic dyssynergia and incontinence need to be conducted. Additionally, to determine if the vector volume can furnish new information in terms of functional and anatomical aspects.

Expert consensus document: Advances in the evaluation of anorectal function

Faecal incontinence and evacuation disorders are common, impair quality of life and incur substantial economic costs worldwide. As symptoms alone are poor predictors of underlying pathophysiology and aetiology, diagnostic tests of anorectal function could facilitate patient management in those cases that are refractory to conservative therapies. In the past decade, several major technological advances have improved our understanding of anorectal structure, coordination and sensorimotor function. This Consensus Statement provides the reader with an appraisal of the current indications, study performance characteristics, clinical utility, strengths and limitations of the most widely available tests of anorectal structure (ultrasonography and MRI) and function (anorectal manometry, neurophysiological investigations, rectal distension techniques and tests of evacuation, including defecography). Additionally, this article provides our consensus on the clinical relevance of these tests.

Diagnostic Tests in Pediatric Constipation

Constipation is one of the most common gastrointestinal symptoms in children. With a median reported prevalence of 12%, it accounts for about 25% of all pediatric gastroenterology consultations. The majority of children experiences functional constipation and do not usually require any diagnostic testing. For those children not responding to conventional medical treatment or in the presence of a more significant clinical picture, however, an accurate instrumental assessment is usually recommended to evaluate either the underlying pathophysiologic mechanisms or a possible organic etiology. The present review analyzes the possible diagnostic investigations for severely constipated children, focusing on their actual indications and their utility in clinical practice. During the last decade, there has been a remarkable increase in our knowledge of normal and abnormal colonic and anorectal motility in children, and a number of different techniques to measure transit and motility have been developed and are discussed in this narrative review.

Regional gastrointestinal contractility parameters using the wireless motility capsule: inter-observer reproducibility and influence of age, gender and study country

BACKGROUND

The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract.

AIMS

To describe normative values for motility/contractility parameters across age, gender and testing centres.

METHODS

Healthy participants underwent a standardised wireless motility capsule assessment following an overnight fast and consumption of a meal of known nutritional content. Traces were divided into regions of interest and analysed using 2 software packages (MotiliGI and GIMS Data Viewer). Inter-observer agreement was independently assessed by 2 investigators.

RESULTS

Normative data for motility/contractility parameters (maximum amplitude, mean peak amplitude, contraction frequency and motility index) are presented for 107 individuals (62 male, median age 40 years, range 18-78). MotiliGI-Gastric, small bowel and colonic maximal contraction amplitude correlated with age (r = .24, P = .01; r = .22, P = .02; and r = .2, P = .04 respectively). Small bowel motility index was higher in females than males (150.4 ± 12 vs 122 ± 7.6, P = .04). Inter-observer agreement was excellent for transit times, pH and contractility/motility parameters. GIMS Data viewer-Gastric, small bowel and colonic log_e motility index correlated with the respective area under the contraction curve, total contractions, sum of amplitudes and contraction frequency (all r>.35, P < .0003) but not with transit times.

CONCLUSIONS

Our analysis provides normative data for motility/contractility parameters. Log motility index summarises a number of measures. In future, the measurement of contractile activity with the wireless motility capsule may potentially aid in the diagnosis of disease states such as visceral myopathic disorders.

Diagnostic accuracy of anorectal manometry for fecal incontinence: a meta-analysis

BACKGROUND

Anorectal manometry (ARM) is conventionally used to assess patients with fecal incontinence (FI). This review aims to establish the diagnostic accuracy of ARM for FI.

METHOD

A search of MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library was performed. Studies examining the sensitivity and specificity of ARM measures, either individually or combined, in the diagnosis of FI, were included. Data analysis was conducted using the bivariate statistical method.

RESULTS

Seven studies were included out of an initial search of 1499 studies. The summary sensitivity and specificity for ARM as an overall test were 0.80 (95% confidence interval (CI): 0.69-0.88) and 0.80 (95% CI: 0.65-0.90), respectively. The diagnostic odds ratio (DOR) for ARM was found to be 16.61 (95% CI: 5.52-50.03). The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) for ARM were found to be 4.09 (95% CI: 2.11-7.94) and 0.25 (95% CI: 0.14-0.42), respectively. Subgroup analysis based on four studies reporting on maximum resting pressure (MRP) demonstrated a sensitivity, specificity, DOR, PLR and NLR of 0.60 (95% CI: 0.38-0.79), 0.93 (95% CI: 0.80-0.97), 20.0 (95% CI: 4.00-91.00), 8.60 (95% CI: 3.00-24.30) and 0.43 (95% CI: 0.24-0.76), respectively.

CONCLUSION

ARM has been shown to be an accurate test for diagnosing FI. Further studies are required to establish the diagnostic accuracy of individual ARM measures.

3D High-definition anorectal manometry: Values obtained in asymptomatic volunteers, fecal incontinence and chronic constipation. Results of a prospective multicenter study (NOMAD)

BACKGROUND

3D-high definition anorectal manometry (3DARM) may aid the diagnosis of functional anorectal disorders, but data comparing asymptomatic and symptomatic subjects are scarce. We aimed to describe 3DARM values in asymptomatic volunteers and those with fecal incontinence (FI) or chronic constipation (CC), and identify which variables differentiate best these groups.

METHODS

Asymptomatic subjects were stratified by sex, age, and parity. Those with FI or CC were included according to anorectal symptom questionnaires. Endoanal ultrasound examination and 3DARM were performed the same day. Anal pressures were analyzed at rest, during voluntary squeeze, and during push maneuver, and compared between the 3 groups. Anal pressure defects were defined and compared to ultrasound defects.

KEY RESULTS

A total of 126 subjects (113 female, mean age 52 years, range 18-83) were included; 36 asymptomatic, 38 FI, 42 CC. Anal resting and squeeze pressures, and rectal sensitivity values were lower in FI women than in the other groups. Typical anal sphincter asymmetry during squeezing was less frequently observed in FI women. A dyssynergic pattern during push maneuver was found in 70% of asymptomatic subjects, and with a similar frequency in the 2 symptomatic groups. There was slight concordance between 3D-pressure defects and ultrasound defects.

CONCLUSIONS & INFERENCES

3D anal pressures in asymptomatic women were significantly lower than in men, and in FI compared to asymptomatic women. The classical dyssynergic pattern during push maneuver was found as frequently in asymptomatic and symptomatic patients. Further studies should try to identify 3DARM variables that could reliably identify dyssynergic defecation.

Methods of anorectal manometry vary widely in clinical practice: Results from an international survey

BACKGROUND

Ano-rectal manometry (ARM) is the most commonly performed investigation for assessment of anorectal dysfunction. Its use is supported by expert consensus documents and international guidelines. Variation in technology, data acquisition, and analysis affect results and clinical interpretation. This study examined variation in ARM between institutions to establish the status of current practice.

METHODS

A 50-item web-based questionnaire assessing analysis and interpretation of ARM was distributed by the International Anorectal Physiology Working Group via societies representing practitioners that perform ARM. Study methodology and performance characteristics between institutions were compared.

KEY RESULTS

One hundred and seven complete responses were included from 30 countries. Seventy-nine (74%) institutions performed at least two studies per week. Forty-nine centers (47%) applied conventional ARM (≤8 pressure sensors) and 57 (53%) high-resolution ARM (HR-ARM). Specialist centers were most likely to use HR-ARM compared to regional hospitals and office-based practice (63% vs 37%). Most conventional ARM systems used water-perfused technology (34/49); solid-state hardware was more frequently used in centers performing HR-ARM (44/57). All centers evaluated rest and squeeze. There was marked variation in the methods used to report results of maneuvers. No two centers had identical protocols for patient preparation, setup, study, and data interpretation, and no center fully complied with published guidelines.

CONCLUSIONS & INFERENCES

There is significant discrepancy in methods for data acquisition, analysis, and interpretation of ARM. This is likely to impact clinical interpretation, transfer of data between institutions, and research collaboration. There is a need for expert international co-operation to standardize ARM.

Childhood constipation: finally something is moving!

Recent developments in the evaluation and treatment of childhood constipation are likely to influence the way we deal with pediatric defecation disorders in the near future. Innovations in both colonic and anorectal manometry are leading to novel insights into functional defecation disorders in children. Promising results have been achieved with innovative therapies such as electrical stimulation and new drugs with targets that differ from conventional pharmacological treatments. Also, new surgical approaches, guided by manometric findings, have led to improvement in patient outcome. Finally, utilization of non-pharmacological interventions such as fiber and probiotics has been a field of particular interest in recent years. The aim of this article is to provide an update on these and other novel diagnostic and therapeutic tools related to childhood constipation.

Measurement of Gastrointestinal and Colonic Motor Functions in Humans and Animals

Accurately measuring the complex motor behaviors of the gastrointestinal tract has tremendous value for the understanding, diagnosis and treatment of digestive diseases. This review synthesizes the literature regarding current tests that are used in both humans and animals. There remains further opportunity to enhance such tests, especially when such tests are able to provide value in both the preclinical and the clinical settings.