Increased Grades of Rectal Intussusception: Role of Decline in Pelvic Floor Integrity and Association with Dyssynergic Defecation.

Background: The natural history of rectal intussusception (RI) is poorly understood. We hypothesized that decline in pelvic floor integrity and function leads to increasing RI grades. Methods: Retrospective analysis of a registry of patients with defecatory disorders with high-resolution anorectal manometry and MR defecography. Association of risk factors on increasing RI grades was assessed using logistic regression. Results: Analysis included a total of 238 women; 90 had no RI, 43 Oxford 1-2, 49 Oxford 3, and 56 Oxford 4-5. Age (p:0.017), vaginal delivery (p: 0.008), and prior pelvic surgery (p: 0.032) were associated with increased Oxford grades. Obstructive defecation symptoms and dyssynergic defecation were observed at relatively high rates across groups. Increased RI grades was associated with less anal relaxation at simulated defecation yet, higher rates of normal balloon expulsion (p<0.05), linked to diminished anal sphincter. Indeed, increased RI grades was associated with worsening fecal incontinence severity, attributed to higher rates of anal hypotension. Levator ani laxity, defined by increased levator hiatus length and its excessive descent at straining, was associated with increasing RI grades, independent of age, history of vaginal delivery, and pelvic surgeries and could independently predict increased RI grades. Concurrent anterior and posterior compartments, and visceral prolapse were associated with higher Oxford grades. Conclusion: Our data suggests that decline in pelvic floor integrity with abnormal levator ani laxity is associated with increased RI grades; a process that is independent of age, history of vaginal deliveries and/or pelvic surgeries, and perhaps related to dyssynergic defecation.