Are pelvic floor movements abnormal in disordered defecation?

Pelvic floor movements were assessed by videoproctography in 126 subjects: neuropathic fecal incontinence patients (n = 44), chronic constipation patients (n = 52), and controls (n = 30). A significantly lower pelvic floor position at rest and a more obtuse anorectal angle were found in incontinent patients than in controls (P less than 0.01). Constipated patients showed no significant difference from controls at rest. There was less pelvic floor movement during contraction in incontinent patients than in controls, indicating a flaccid, noncontractile pelvic floor in neuropathic incontinence. Movement during contraction in constipated subjects was also less than in controls. Changes in the pelvic floor position during straining were the same as in controls. These data indicate that the pelvic floor is flaccid and noncontractile in neuropathic fecal incontinence, which supports the concept of a progressive neuropathy involving the sacral outflow. Similar changes are not seen at rest in patients with constipation even though they have a long history of straining.