Measurement of anal cushions in idiopathic faecal incontinence

Abstract

Faecal incontinence affects a heterogeneous population and aetiology can be multifactorial. In a subset of patients the aetiology remains idiopathic despite standard investigations. Anal cushions are important in normal continence, but have rarely been studied. The aim of this study was to measure the size of the anal cushions and to evaluate their role in patients with idiopathic faecal incontinence. Women in whom idiopathic faecal incontinence was diagnosed after standard anorectal investigations underwent transvaginal ultrasonography. The area of the anal cushions was measured and a cushion : canal (C : C) ratio derived, which was compared with that in a control group of women without faecal incontinence. Some 21 patients with incontinence (median age 60 years) and 102 asymptomatic controls (median age 41 years) underwent scanning. The median (interquartile range) C : C ratio in the symptomatic group was significantly lower than that for controls (0.57 (0.54-0.66) versus 0.68 (0.61-0.73) respectively; P = 0.001). C : C ratio was not influenced by age (r = 0.023, P = 0.821). The C : C ratio was reduced in patients with idiopathic faecal incontinence.