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

BACKGROUND: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. OBJECTIVE:This study evaluates the association among rectal intussusception, constipation, fecal incontinence, and anorectal manometry. DESIGN: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. SETTINGS:The study was conducted at a tertiary care university medical center (Massachusetts General Hospital). PATIENTS: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. MAIN OUTCOME MEASURES:Symptom severity and quality-of-life scores were measured, as well as anal manometry results. RESULTS:Increasing Oxford grade was associated with an increase in severity of fecal incontinence (median scorenormal = 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 pressurenormal = 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 scorenormal = 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). LIMITATIONS:The study was limited because it was an observational study from a single center. CONCLUSIONS:Increasing grades of rectal intussusception are associated with increasing fecal incontinence but not constipation.