Rectal intussusception and unexplained faecal incontinence: findings of a proctographic study

The aetiology of faecal incontinence is multifactorial, yet there remains an approach to assessment and treatment that focusses on the sphincter. Rectal intussusception (RI) is underdiagnosed and manifests primarily as obstructed defecation. Yet greater than 50% of these patients admit to faecal incontinence on closer questioning. We aimed to evaluate the incidence of RI at evacuation proctography selectively undertaken in the evaluation of patients with faecal incontinence. Patients with faecal incontinence seen in a pelvic floor clinic were evaluated with anorectal physiology and ultrasound. Where the faecal incontinence was not fully explained by physiology and ultrasound, evacuation proctography was undertaken. Studies were classified as 'normal', 'low-grade RI' (recto-rectal), 'high-grade RI' (recto-anal) or 'anismus'. Forty patients underwent evacuation proctography (33 women, 83%). Median age was 63 years (range 34-77 years). Seven patients (17%) had a normal proctogram. Three (8%) had recto-rectal RI. Twenty-five (63%) demonstrated recto-anal RI. Five patients (12%) had anismus. Recto-anal intussusception is common in patients undergoing selective evacuation proctography for investigation of faecal incontinence. The role of recto-anal intussusception in the multifactorial aetiology of faecal incontinence has been largely overlooked. Evacuation proctography should be considered as part of routine work-up of patients with faecal incontinence.