Defecation 2: Internal anorectal resistance is a critical factor in defecatory disorders

Bush, Mark B.; Petros, Peter; Swash, Michael; Fernández, Manuel; Gunnemann, A.

doi:10.1007/s10151-012-0860-3

Cited by 22 publications

(20 citation statements)

References 10 publications

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“…This method of analysis followed that introduced by Bush et al [14] to explain the role of anorectal geometry in evacuation disorders and is based on the fact that evacuation of the rectum results from pressure-induced plastic deformation of the content by squeezing it through the anal canal [13,34]. We extend their analysis to show the consequences of a high yield stress on evacuation in a geometric model.…”

Section: Modeling Of Faeces Evacuation Using Flow Lawsmentioning

confidence: 94%

“…Ultimately defaecation involves the physical resistance of faeces to flow [11][12][13][14][15], i.e. the flow rate in relation to the intrarectal pressure generated by motility and motricity and depends, largely, on the relative geometry of the rectum and anus.…”

Section: Introductionmentioning

confidence: 99%

“…If we consider the flow of soft matter within a geometrically defined space such as the rectoanal junction, the relationships between pressure, flow rate, geometry and yield stress can be determined mathematically by the use of appropriate flow laws [12,14]. Hence models which incorporate colo-recto-anal motility and motricity (pressure), anatomy (geometry) along with the relevant yield stress (rheology) of the faeces allow us to evaluate the principal parameters that govern faecal evacuation (flow rate) and the aetiology of associated pathophysiological disorders.…”

Section: Introductionmentioning

confidence: 99%

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Rheology of human faeces and pathophysiology of defaecation

Loubens

Lentle

et al. 2020

Tech Coloproctol

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Background: Rectal evacuation involves multiple mechanisms that are not completely understood. The aim of this study was to quantify the rheologic property, i.e. yield stress, that governs the ease of deformation of a range of faeces of differing consistency and understand its influence on the pathophysiology of defaecation. Methods: Yield stresses of faeces of differing consistencies and Bristol scores were determined by the Vane test. We then explored the effects of this property on ease of defecation using a simple static model of the recto-anal junction based on the laws of flow for yield stress pastes and checked the conclusions by X-ray defaecography experience. Results: The yield stress of faeces increased exponentially with their solid content, from 20 to 8000 Pa. The static model of the recto-anal junction showed that evacuation of faeces of normal consistency and yield stress is possible with moderate dilatation of the anal canal, whilst the evacuation of faeces with higher yield stress requires greater dilatation of the anal canal. X-ray defaecography showed that such increases occurred in vivo. Conclusions: The diameter of the recto-anal junction is increased to enable the passage of feces with high yield stress. The finite limits to such dilation likely contribute to fecal impaction. Hence difficulties in defaecation may result either from unduly high yield stress or pathologies of reflex recto-anal dilatation or a combination of the two.

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Section: Modeling Of Faeces Evacuation Using Flow Lawsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rheology of human faeces and pathophysiology of defaecation

Loubens

Lentle

et al. 2020

Tech Coloproctol

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“…From a bioengineering perspective, modeling efforts should first focus on construction of anatomically correct models, mechano-physiological models, and finally mechanosensory models can be advanced [13,24,38,[51][52][53][54][55]. Anorectal models have been proposed [25,56,57] and are currently based on flow equations that are relatively simple for describing defecatory function. The purpose of mathematical modeling is to be able to predict the occurrence/non-occurrence of the event in question.…”

Section: Advanced Analysis and Modelingmentioning

confidence: 99%

Novel Bionics Assessment of Anorectal Mechanosensory Physiology

Gregersen

2020

Bioengineering

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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.

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“…Average age was 13.7 AE 3.1 years (range [8][9][10][11][12][13][14][15][16][17][18][19] and 55% were girls. Average age was 13.7 AE 3.1 years (range [8][9][10][11][12][13][14][15][16][17][18][19] and 55% were girls.…”

Section: Effect Of Balloon Inflation On Rectal and Anal Canal Pressuresmentioning

confidence: 99%