An update on anorectal disorders for gastroenterologists

Abstract

Gastroenterologists frequently encounter pelvic floor disorders, which affect 10% to 15% of the population. The anorectum is a complex organ that collaborates with the pelvic floor muscles to preserve fecal continence and enable defecation. A careful clinical assessment is critical for the diagnosis and management of defecatory disorders and fecal incontinence. Newer diagnostic tools (eg, high-resolution manometry and magnetic resonance defecography) provide a refined understanding of anorectal dysfunctions and identify phenotypes in defecatory disorders and fecal incontinence. Conservative approaches, including biofeedback therapy, are the mainstay for managing these disorders; new minimally invasive approaches may benefit a subset of patients with fecal incontinence, but more controlled studies are needed. This mini-review highlights advances, current concepts, and controversies in the area.

Keywords: Anorectal Manometry; Biofeedback Therapy; DD; DRE; Dyssynergic Defecation; FI; Fecal Incontinence; IAS; ICC; MRI; ROCK; RhoA–RhoA kinase; SNS; defecatory disorder; digital rectal examination; fecal incontinence; internal anal sphincter; interstitial cells of Cajal; magnetic resonance imaging; sacral nerve stimulation.

Figure 1. Representative examples of anorectal pressure phenotypes identified by high resolution manometry in defecatory disorders

Pressures at rest, during squeeze and evacuation were recorded by 12 sensors (2 in the rectal balloon and 10 in the anal canal) and are depicted in color; the numbers reflect the distance of sensors from anal verge. High anal, low rectal and hybrid phenotypes are defined by anal, rectal and combined rectoanal dysfunction respectively. During evacuation: (i) anal relaxation was normal in the rectal phenotype but absent in the “high anal” and “hybrid” patterns. Anal resting pressure was also higher in the anal phenotype, (ii) rectal (balloon) pressure increased, as evidenced by color change from blue to green in the rectal balloon, in the high anal phenotype only.

Figure 2

Algorithm for managing defecatory disorders Reproduced with permission from Bharucha AE, Dorn SD, Lembo A, Pressman A. American Gastroenterological Association Medical Position Statement on Constipation Gastroenterologygy 2013; 144(1):211–17 (left panel)

Figure 3

Algorithm for managing fecal incontinence.