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

Abstract

BackgroundThis 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.MethodsTwenty‐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 recommendationsThe 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 InferencesThis 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.

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

“…Indeed, a 2019 consensus document recommends that manometry "should be performed in the left lateral position." 18 During evacuation, the default ManoScan™ (Medtronic Inc, Minneapolis, MN) software algorithm for analyzing HRM identifies the highest rectoanal gradient (RAG) over a consecutive period of 2 seconds during the 20-second maneuver. (We use a duration of 3 seconds, which is arguably more representative of evacuation than the default ManoView™ option of 2 seconds.)…”

Isolated puborectalis muscle contraction is a common cause of dyssynergic defecation in constipated adolescents and adults with anorectal malformations

“…Moreover the left lateral decubitus position is recommended by The International Anorectal Physiology Working Group. 21 When it comes to treatment for DD, coaching has in one study revealed a normalization of manometric results in 12 out of 39 patients. 26 Type I DD was dominant in our patients with constipation, found in eight out of 13 cases.…”

“…In patients ful lling the diagnostic criteria for functional chronic constipation, dyssynergic defecation (DD) was de ned according to the following diagnostic criteria which have shown to be in line with the London Classi cation. 20,21 1. Patients must demonstrate an obstructive pattern of defecation during high resolution anorectal manometry at more than one attempt…”

Anorectal Physiology Testing for Prolapse—What Tests are Necessary?

“…The test provides information such as (1) voluntary and involuntary anal sphincter function including measurement of the resting and squeeze sphincter pressure, and the functional length of the anal canal, (2) rectoanal inhibitory reflex (RAIR) activity during rectal distension, (3) rectal sensation, (4) rectal compliance, and (5) evacuatory function. [2][3][4] Definitions of several of these measures along with others commonly used to describe anorectal physiology are provided in ►Table 1. 5 An ARM study requires four main equipment consisting of a probe, pressure recording device, device for displaying the recordings (e.g., monitor or printer), and a device for both data analysis and storage (e.g., computer or chart recorder).…”

“…In some ARM protocols, a "cough" is also included between the "squeeze" and "push" phases to document the cough pressure. 3 Dyssynergic defecation occurs when a patient is unable to coordinate their abdominal and pelvic floor muscles to successfully evacuate stool 11 (►Fig. 2).…”