Identification of a sphincter at the sigmoidorectal canal in humans: Histomorphologic and morphometric studies

Shafik, Ahmed; Asaad, Soheir; Doss, Sameh

doi:10.1002/ca.10054

Cited by 8 publications

(3 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More recently, Shafik et al. showed the presence of a short segment of thickened muscular layer at the rectosigmoid junction when compared with the sigmoid colon and rectum; however, this was not identified in all specimens in these studies. With scant supporting evidence, in the modern era, most researchers and clinicians are satisfied that there is no distinct anatomic sphincter in this region …”

Section: Anatomy Of the Rectosigmoid Regionmentioning

confidence: 74%

The “rectosigmoid brake”: Review of an emerging neuromodulation target for colorectal functional disorders

Lin

Dinning

Milne

et al. 2017

Clin Exp Pharma Physio

View full text Add to dashboard Cite

SummaryThe regulation of gastrointestinal motility encompasses several overlapping mechanisms including highly regulated and coordinated neurohormonal circuits. Various feedback mechanisms or "brakes" have been proposed. While duodenal, jejunal, and ileal brakes are well described, a putative distal colonic brake is less well defined.Despite the high prevalence of colonic motility disorders, there is little knowledge of colonic motility owing to difficulties with organ access and technical difficulties in recording detailed motor patterns along its entire length. The motility of the colon is not under voluntary control. A wide range of motor patterns is seen, with long intervals of intestinal quiescence between them. In addition, the use of traditional manometric catheters to record contractile activity of the colon has been limited by the low number of widely spaced sensors, which has resulted in the misinterpretation of colonic motor patterns. The recent advent of high-resolution (HR) manometry is revolutionising the understanding of gastrointestinal motor patterns. It has now been observed that the most common motor patterns in the colon are repetitive two to six cycles per minute (cpm) propagating events in the distal colon. These motor patterns are prominent soon after a meal, originate most frequently in the rectosigmoid region, and travel in the retrograde direction. The distal prominence and the origin of these motor patterns raise the possibility of them serving as a braking mechanism, or the "rectosigmoid brake," to limit rectal filling. This review aims to describe what is known about the "rectosigmoid brake," including its physiological and clinical significance and potential therapeutic applications. K E Y W O R D Scolon, gastrointestinal motility, gastrointestinal tract, high-resolution manometry, rectosigmoid brake | INTRODUCTIONColonic motility disorders are prevalent in the general population and can have a significant impact on quality of life.1-3 Gastrointestinal transit and the act of defaecation require a coordinated interplay between intrinsic neurohormonal circuits acting on a morphologically intact gastrointestinal tract. These are highly auto-regulated and coordinated events, optimised for ideal transit, maximum absorption, and timely elimination of waste products.Networks of gastrointestinal "brakes" have long been proposed to provide negative feedback controls on gastrointestinal motility. 4-12Duodenal and jejunal brakes are recognised responses to the arrival of nutrient-dense chyme into the upper small intestine, triggering neurohormonal circuits that impart feedback control on gastric emptying, gastric distention and satiety. 6,8 Distally, the ileal brake is capable of a potent inhibition of intestinal motility following the arrival of nutrients, with additional effects including delaying gastric emptying and promoting satiety. 7,10 Motility brakes within the colon and rectum have also been described, though they remain less well established.Published examples include withholding de...

show abstract

Section: Anatomy Of the Rectosigmoid Regionmentioning

confidence: 74%

The “rectosigmoid brake”: Review of an emerging neuromodulation target for colorectal functional disorders

Lin

Dinning

Milne

et al. 2017

Clin Exp Pharma Physio

View full text Add to dashboard Cite

show abstract

“…While the pressure in the sigmoid colon increases, this functional RSS relaxes. In response to increased pressure in the rectum, its tonus rises 12 . Different reactions of RSS to different volume of the balloon were found.…”

Section: Discussionmentioning

confidence: 99%

Pathophysiology of the functional constipation in elderly

Levin¹

2019

PPJ

View full text Add to dashboard Cite

The aim of this study was to investigate the pathophysiology of functional constipation (FC) in the elderly. Material and methods: In the State Geriatric Center of Netanya (Israel), 37 patients at the age of 65-93 years with complaints of chronic constipation were examined. This main group did not include patients with tumors and cases after surgery on the rectum and colon. The results of a survey of 15 young people aged 11-17 years with no bowel disease were taken as a control group. A barium enema with a radiopaque marker near the anus was produced. A frontal radiography of the abdomen as well as an X-ray of the lateral projection of the anorectal zone were made after the administration of 100, 200 and 300 ml of barium. Results: In 6 (16%) cases, the width of the rectum was more than 5 cm - megarectum. The length of the anal canal was 2 times less than the minimum normal limit after the injection of 100 ml of barium. In 25 (68%) patients, the width of the rectum was normal and had a normal shape. The functioning anal canal length was shortened during the administration of barium. In 6 (16%) patients, the reason for constipation was high colonic tone. They had the anorectal parameters within the normal range. Conclusion: We found 3 types of FC in the elderly. In the structure of FC the cases of self-defined constipation (68%) are dominated, where there is no mechanical obstruction for defecation. The reason for the sense of constipation and incomplete emptying is due to the age-related weakness of the pelvic floor muscles. In 16% of patients, obstructive constipation with a megarectum and a fixed descending perineum syndrome was detected. This pathology originated in childhood or after anal fissures, and childbirth. In 16% of patients, the cause of constipation was a high tone of the colon, what can be the result of an irritable bowel syndrome, the formation of functional sphincters in the colon and diverticula of the sigmoid colon. An increase in the tone of the colon causes a slow transit constipation.

show abstract

“…From this work he proposed a mass squeeze action of the rectum aborally towards the anal canal [127,128] with a separable rectosigmoid pacemaker site [129,130] transmitted through the longitudinal muscle on distension and abrogated by longitudinal myotomy [131,132]. This work informed his suggestion for the treatment of severe constipation by colonic and rectal pacing using mucosally positioned pacing electrodes and home pacing with a subcutaneously implanted electrical stimulator.…”

Section: Colorectal Pacemakersmentioning

confidence: 98%

Anorectal morphology and function: analysis of the Shafik legacy

Zbar

Guo

Pescatori³

2008

Tech Coloproctol

View full text Add to dashboard Cite

Following the untimely death of Professor Ahmed Shafik, the authors decided to analyse his published work on the anatomy and physiology of the anorectal area, reconciling this body of data with current imaging and physiological techniques. All available papers as indexed by PubMed pertaining to the anorectal area were obtained and reviewed. The anatomical data was compared with historical representations and current new imaging modalities. The original 'triple-loop' theory of the anatomical disposition of the external anal sphincter has been confirmed by coronal and coronally reconstructed imaging modalities. There is variance between the Shafik and other descriptions of the anatomy of the longitudinal muscle and its importance in the definition of perianal spaces which are important in the spread of perirectal sepsis and in intersphincteric rectal dissection. Current dynamic defaecography would suggest a more complex levator plate function in squeeze and straining than that originally suggested by Shafik as a primary defaecatory role for the levator muscle. The body of work by Professor Shafik has reorganized our understanding of the external anal sphincter and the function of the levator during defaecation. Future studies should assess anatomical and physiological variances using new technology in health and in specific disease states.

show abstract

Identification of a sphincter at the sigmoidorectal canal in humans: Histomorphologic and morphometric studies

Cited by 8 publications

References 12 publications

The “rectosigmoid brake”: Review of an emerging neuromodulation target for colorectal functional disorders

The “rectosigmoid brake”: Review of an emerging neuromodulation target for colorectal functional disorders

Pathophysiology of the functional constipation in elderly

Anorectal morphology and function: analysis of the Shafik legacy

Contact Info

Product

Resources

About