Background Until recently, investigations of the normal patterns of motility of the healthy human colon have been limited by the resolution of in vivo recording techniques. Methods We have used a new, high-resolution fiber-optic manometry system (72 sensors at 1-cm intervals) to record motor activity from colon in 10 healthy human subjects. Key Results In the fasted colon, on the basis of rate and extent of propagation, four types of propagating motor pattern could be identified: (i) cyclic motor patterns (at 2–6/min); (ii) short single motor patterns; (iii) long single motor patterns; and (iv) occasional retrograde, slow motor patterns. For the most part, the cyclic and short single motor patterns propagated in a retrograde direction. Following a 700 kCal meal, a fifth motor pattern appeared; high-amplitude propagating sequences (HAPS) and there was large increase in retrograde cyclic motor patterns (5.6±5.4/2 h vs 34.7±19.8/2 h; p < 0.001). The duration and amplitude of individual pressure events were significantly correlated. Discriminant and multivariate analysis of duration, gradient, and amplitude of the pressure events that made up propagating motor patterns distinguished clearly two types of pressure events: those belonging to HAPS and those belonging to all other propagating motor patterns. Conclusions & Inferences This work provides the first comprehensive description of colonic motor patterns recorded by high-resolution manometry and demonstrates an abundance of retrograde propagating motor patterns. The propagating motor patterns appear to be generated by two independent sources, potentially indicating their neurogenic or myogenic origin.

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.

Chronic constipation is a prevalent condition that severely impacts the quality of life of those affected. Several types of primary chronic constipation, which show substantial overlap, have been described, including normal-transit constipation, rectal evacuation disorders and slow-transit constipation. Diagnosis of primary chronic constipation involves a multistep process initiated by the exclusion of 'alarm' features (for example, unintentional weight loss or rectal bleeding) that might indicate organic diseases (such as polyps or tumours) and a therapeutic trial with first-line treatments such as dietary changes, lifestyle modifications and over-the-counter laxatives. If symptoms do not improve, investigations to diagnose rectal evacuation disorders and slow-transit constipation are performed, such as digital rectal examination, anorectal structure and function testing (including the balloon expulsion test, anorectal manometry or defecography) or colonic transit tests (such as the radiopaque marker test, wireless motility capsule test, scintigraphy or colonic manometry). The mainstays of treatment are diet and lifestyle interventions, pharmacological therapy and, rarely, surgery. This Primer provides an introduction to the epidemiology, pathophysiological mechanisms, diagnosis, management and quality of life associated with the commonly encountered clinical problem of chronic constipation in adults unrelated to opioid abuse.

© 2 0 1 8 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d .on already available consensus statements 3,4 . Consensus statements from other gastrointestinal societies or expert groups were searched for and included when appropriate, for example, if they were published more recently or if they covered relevant areas not specifically addressed in the previous documents 3,4 . Moreover, an updated literature search using PubMed and Medline was performed centrally by the corresponding author (J.K.) with additions from the co-authors. The literature search started on the date specified as the end date of the lite ature searches performed for two previously published consensus papers 3,4 (that is, 1 Jan 2008 for intraluminal measure ments of gastrointestinal motility and 1 Jan 2010 for transit tests); the search covered the period until 14 Apr 2016 and was generally limited to human studies. The literature search revealed 1,111 publications, of which 202 were selected on the basis of study quality (which did not include a formal evaluation, but the level of evidence was assessed in line with the Oxford Centre for Evidence-based Medicine (https://www.cebm.net/2009/06/oxford-centre-evidencebased-medicine-levels-evidence-march-2009/) and were made available to all authors. Low-quality studies were also considered if the topic was deemed rele vant and not covered otherwise. The literature search on gastric emptying included the following terms, revealing 624 papers: "gastric emptying", "gastro paresis", "dumping", "measurement", "test", "evalu ation" and "diagnosis". The literature search on intra luminal tests of gastric motility included the following terms, revealing 67 papers: "gastric", "antral", "antro duo denal", "antro duodenojejunal", "motility", "contraction", "intraluminal" and "mano metry". The literature search on small bowel transit included the following terms, revealing 130 papers: "orocaecal transit", "OCCT", "small bowel transit", "intestinal transit", "measurement", "test", "evaluation", "diagnosis", "sensitivity" and "specificity". The literature search on intraluminal tests of small bowel motility included the following terms, revealing 13 papers: "small bowel", "antroduodenal", "antroduodenojejunal", " intestinal", "intraluminal", "motility" and "manometry".The literature search on colonic transit included the following terms, revealing 222 papers: "colonic transit", "Hinton", "measurement", "test", "evaluation", "diagnosis", "sensitivity" and specificity. The literature search on intraluminal tests of colonic motility included the follow ing terms, revealing 55 papers: "colonic", " motility", "contraction", "intraluminal" and "manometry".Statements were distributed via e-mail, and each author had to confirm full agreement, minor concerns or disagreement in writing. Concerns or disagreement had to be explained. All statements with at least one author in disagreement or more than three authors with minor concerns were modi...

Postoperative ileus (POI) is an abnormal pattern of gastrointestinal motility characterized by nausea, vomiting, abdominal distension and/or delayed passage of flatus or stool, which may occur following surgery. Postoperative ileus slows recovery, increases the risk of developing postoperative complications and confers a significant financial load on healthcare institutions. The aim of the present review is to provide a succinct overview of the clinical features and pathophysiological mechanisms of POI, with final comment on selected directions for future research.Terminology used when describing POI is inconsistent, with little differentiation made between the obligatory period of gut dysfunction seen after surgery ('normal POI') and the more clinically and pathologically significant entity of a 'prolonged POI'. Both normal and prolonged POI represent a fundamentally similar pathophysiological phenomenon. The aetiology of POI is postulated to be multifactorial, with principal mediators being inflammatory cell activation, autonomic dysfunction (both primarily and as part of the surgical stress response), agonism at gut opioid receptors, modulation of gastrointestinal hormone activity and electrolyte derangements. A final common pathway for these effectors is impaired contractility and motility and gut wall oedema. There are many potential directions for future research. In particular, there remains scope to accurately characterize the gastrointestinal dysfunction that underscores an ileus, development of an accurate risk stratification tool will facilitate early implementation of preventive measures and clinical appraisal of novel therapeutic strategies that target individual pathways in the pathogenesis of ileus warrant further investigation.

In patients with STC a meal fails to induce the normal increase in the distal colonic cyclic propagating motor patterns. We propose that these data may indicate that the normal extrinsic parasympathetic inputs to the colon are attenuated in these patients.

These data demonstrate that SNS induces pan-colonic propagating pressure waves and therefore shows promise as a potential therapy for severe refractory constipation.

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