Impact of Rising Grades of Internal Rectal Intussusception on Fecal Continence and Symptoms of Constipation.

A theory of rectal intussusception has been advanced that intrarectal intussusception, intra-anal intussusception, and external rectal prolapse are points on a continuum and are a cause of fecal incontinence and constipation.This study evaluates the association among rectal intussusception, constipation, fecal incontinence, and anorectal manometry.Patients undergoing defecography were studied from a prospectively maintained database and classified according to the Oxford Rectal Prolapse Grade as normal or having intra-rectal, intra-anal, or external intussusception. Patient symptoms were assessed using the Constipation Severity Index and the Fecal Incontinence Severity Index. Quality-of-life surveys were also used. Patients also underwent anorectal manometry.The study was conducted at a tertiary care university medical center (Massachusetts General Hospital).The study included 147 consecutive patients undergoing evaluation for evacuatory dysfunction and involved defecography, symptoms questionnaires, and anorectal physiology testing from January 2011 to December 2013.Symptom severity and quality-of-life scores were measured, as well as anal manometry results.Increasing Oxford grade was associated with an increase in severity of fecal incontinence (median score: normal = 23.9, intrarectal = 21.0, intra-anal = 30.0, external prolapse = 35.3; β = 4.71; p = 0.009), which persisted in a multivariable model including age (β = 2.13; p = 0.03), and decreased sphincter pressures (median mean resting pressure: normal = 75.4, intra-rectal = 69.7, intra-anal = 64.3, external prolapse = 48.3; β = -8.57; p = 0.003), which did not persist in a multivariable model. Constipation severity did not increase with rising intussusception (mean score: normal = 37.4, intrarectal = 35.0, intra-anal = 41.4, external prolapse = 32.9; p = 0.79), and balloon expulsion improved rather than worsened (normal = 47.1%, intrarectal = 60.5%, intra-anal = 82.9%, external prolapse = 93.1%; p < 0.001).The study was limited because it was an observational study from a single center.Increasing grades of rectal intussusception are associated with increasing fecal incontinence but not constipation.