Anorectal pressure gradient in patients with anal incontinence.

Anorectal pressures in patients with fecal incontinence have been investigated. With anal manometry, 34 percent of patients with fecal incontinence had maximal resting pressure and 39 percent had maximal squeeze pressure within the normal range. When a pressure gradient was calculated as the pressure difference between maximal resting pressure and rectal pressuring during filling of a rectal balloon, patients with fecal incontinence could be better distinguished from controls: 20 percent of patients with fecal incontinence had values within the normal range when the rectal pressure at the earliest defecation urge was used (P less than 0.05), and 12 percent had values within the normal range when the rectal pressure at maximal tolerable volume was used (P less than 0.01). Anorectal pressure gradient measurements seem to distinguish patients with fecal incontinence from controls better than maximal resting pressure or maximal squeeze pressure alone.