Emma V. Carrington

Traditional measures of normal anal sphincter function using high-resolution anorectal manometry (HRAM) in 115 healthy volunteers

High‐resolution anorectal manometry (HRAM) is a relatively new method for collection and interpretation of data relevant to sphincteric function, and for the first time allows a global appreciation of the anorectum as a functional unit. Historically, traditional anal manometry has been plagued by lack of standardization and healthy volunteer data of variable quality. The aims of this study were: (i) to obtain normative data sets for traditional measures of anorectal function using HRAM in healthy subjects and; (ii) to qualitatively describe novel physiological phenomena, which may be of future relevance when this method is applied to patients.

Diagnostic accuracy study of anorectal manometry for diagnosis of dyssynergic defecation

Objective The diagnostic accuracy of anorectal manometry (AM), which is necessary to diagnose functional defecatory disorders (FDD), is unknown. Using blinded analysis and standardised reporting of diagnostic accuracy, we evaluated whether AM could discriminate between asymptomatic controls and patients with functional constipation (FC). Design Derived line plots of anorectal pressure profiles during simulated defecation were independently analysed in random order by three expert observers blinded to health status in 85 women with FC and 85 age-matched asymptomatic healthy volunteers (HV). Using accepted criteria, these pressure profiles were characterised as normal (ie, increased rectal pressure coordinated with anal relaxation) or types I–IV dyssynergia. Interobserver agreement and diagnostic accuracy were determined. Results Blinded consensus-based assessment disclosed a normal pattern in 16/170 (9%) of all participants and only 11/85 (13%) HV. The combined frequency of dyssynergic patterns (I–IV) was very similar in FC (80/85 (94%)) and HV (74/85 (87%)). Type I dyssynergia (‘paradoxical’ contraction) was less prevalent in FC (17/85 (20%) than in HV (31/85 (36.5%), p=0.03). After statistical correction, only type IV dyssynergia was moderately useful for discriminating between FC (39/85 (46%)) and HV (17/85 (20%)) (p=0.001, positive predictive value=70.0%, positive likelihood ratio=2.3). Interobserver agreement was substantial or moderate for identifying a normal pattern, dyssynergia types I and IV, and FDD, and fair for types II and III. Conclusions While the interpretation of AM patterns is reproducible, nearly 90% of HV have a pattern that is currently regarded as ‘abnormal’ by AM. Hence, AM is of limited utility for distinguishing between FC and HV.

The influence of sacral nerve stimulation on anorectal dysfunction.

Aim  Sacral nerve stimulation (SNS) has become an established option in the management of defaecatory disorders. There are many data on the end‐organ effects of SNS, but limited consensus on its mechanism of action. The objective of this review was to determine the effect of sacral nerve stimulation (SNS) on anorectal function.

Assessment of rectal afferent neuronal function and brain activity in patients with constipation and rectal hyposensitivity.

Background  Blunted rectal sensation (rectal hyposensitivity: RH) is present in almost one‐quarter of patients with chronic constipation. The mechanisms of its development are not fully understood, but in a proportion, afferent dysfunction is likely. To determine if, in patients with RH, alteration of rectal sensory pathways exists, rectal evoked potentials (EPs) and inverse modeling of cortical dipoles were examined.

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

In the esophagus, high‐resolution manometry (HRM) has become a standard diagnostic tool in the investigation of suspected motility disorders. However, at the opposite end of the digestive tract (i.e., the colon and anorectum), the use of HRM still remains in its infancy, with relatively few published studies in the scientific literature. Further, the clinical utility of those studies that have been performed is largely undetermined.

Normal values for high-resolution anorectal manometry: a time for consensus and collaboration

To the Editors We read with interest the manuscript recently published in your journal by Lee et al. The authors reported the influence of gender (when adjusted for the effect of age, body mass index, and vaginal delivery) on anorectal function using high-resolution manometry (HRM) in 54 ageand sex-matched asymptomatic healthy Korean volunteers. Over the last 10 years, HRM within the esophagus has revolutionized the diagnosis and management of a number of conditions of esophageal dysmotility. For this reason, investigation of the advantages that anorectal HRM may offer is a topic that is currently attracting significant interest in clinical practice, which now presents an opportunity similar to that of the Chicago process to reach agreement regarding standardization of this new and promising technique. The study by Lee et al. highlights a number of longstanding issues that have bedeviled clinical research within the field of anorectal manometry. Firstly, are the difficulties arising from differences in published results between centers. To date, there are five studies within the literature reporting the use of HRM in healthy populations. Equipment and protocols (including analysis methods) vary widely among published articles, despite the appreciation that this may affect absolute results. For example, Lee et al. report a median anal squeeze increment of 20 mmHg in the female population (n = 27). By contrast, a study by our group, also published within your journal this month, reports a 5th percentile for anal squeeze increment in healthy females (n = 96) of 45 mmHg (with this value suggested as a cutoff for normality). The reasons for these discrepancies are likely numerous. Although we agree with the suggestion by the authors of the influence of ethic characteristics, a recent article presenting results of HRM in healthy Asian volunteers reports values similar to those including participants from Western countries. It is our feeling that limitations in study design are more likely tobethemaindriver fordiscrepanciesbetweenresults. In particular, comparison of the effects of multiple independent variables (such as age, sex, and parity) using multivariate regressionmakes a number of assumptions about the data. Lee et al. aimed to identify the independent effects of four predictors on anorectal HRM parameters in a cohort of only 54 subjects. Tabachnick and Fidell give a formula for calculating sample size requirements (taking into account the number of independent variables: N > 50 + 8 m, where m = number of independentvariables),whichisviolatedinthecurrentstudy. One of the principle challenges will be to establish normative datasets of an adequate size and to promote standardization of the technique so that results are transferrable between institutions, a problem that has similarly compounded traditional practice. We call for such consensus so as to avoid the pitfalls that have affected standard HRM (and all other tests of anorectal function).

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

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.

Pathophysiology of fecal incontinence differs between men and women: a case‐matched study in 200 patients

Fecal incontinence (FI) is a common and socially disabling condition with obstetric trauma considered the principal etiological factor. This study aimed to systematically evaluate symptom presentation and anorectal function in both females and males with FI.

Colonic and anorectal motility testing in the high-resolution era.

Purpose of review The past few years have seen an increase in the number of research and clinical groups around the world using high-resolution manometry (HRM) to record contractile activity in the anorectum and colon. Yet despite the uptake and growing number of publications, the clinical utility and potential advantages over traditional manometry remain undetermined. Recent findings Nearly all of the publications in the field of anorectal and colonic HRM have been published within the last 3 years. These studies have included some data on normal ranges in healthy adults, and abnormalities in patient groups with constipation or fecal incontinence, anal fissure, perineal descent, rectal cancer, and Hirschsprungs disease. Most of the studies have been conducted on adults, with only three published studies in pediatric populations. Very few studies have attempted to show advantages of HRM over traditional manometry Summary High-resolution anorectal and colonic manometry provide a more comprehensive characterization of motility patterns and coordinated activity; this may help to improve our understanding of the normal physiology and pathophysiology in these regions. To date, however, no published study has conclusively demonstrated a clinical, diagnostic, or interventional advantage over conventional manometry:

Advancement anoplasty and sacral nerve stimulation: an effective combination for radiation-induced anal stenosis.

IntroductionPelvic radiotherapy can cause anal stenosis. Patients can be left with severe rectal evacuatory difficulties, anal fissuring and resistant faecal incontinence. The management of such patients is difficult since surgical treatment can worsen faecal incontinence.Case studyWe report a patient who was treated for recurrent fissuring and faecal incontinence secondary to severe anal stenosis caused by external beam radiotherapy to his prostate. A 74-year-old male patient underwent excision of the fissuring, fibrotic anal mucosa and internal sphincter and was then treated with a broad-based House advancement anoplasty. The patient’s fissuring was successfully treated but he still suffered from faecal incontinence. The patient underwent sacral nerve stimulation with significant improvement in all faecal incontinence symptoms.ConclusionThe use of a novel combination of a House advancement anoplasty and sacral nerve stimulation is a safe and effective treatment rationale for treatment of radiation-induced anal stenosis.