Clinical value of anorectal manometry index in neurogenic fecal incontinence

PURPOSE: The present communication is an endeavor to assess the value of a simple motility index to separate patients with neurogenic or idiopathic fecal incontinence from those patients with the secondary form of the disease. METHODS: Study population consisted of 23 patients with idiopathic fecal incontinence and 13 patients with fecal incontinence secondary to surgical or obstetric trauma. They all had a standard anorectal manometric study after a 12-hour fast. A motility index was then prepared taking into consideration the peak sphincter pressure values, contractility endurance, and rectal sensory threshold. RESULTS: Despite differences in the mean peak squeeze pressure and sensory threshold between the two groups, there were significant overlaps for all parameters of standard anorectal manometry in both groups. However, patients with idiopathic incontinence had an index of smaller than 28, and the group with the secondary form of incontinence had indexes higher than 30. CONCLUSIONS: 1) None of the four parameters of a conventional anorectal manometry can accurately separate patients with neurogenic incontinence from those with secondary forms of the disorder. 2) The anorectal motility index presented here can accurately separate the two groups. 3) This index is superior to the standard anorectal manometry in evaluating patients with fecal incontinence.