Discriminative Value of Anorectal Manometry in Clinical Practice

Abstract

Guidelines recommend anorectal manometry in patients with fecal incontinence and chronic constipation. However, limited evidence supports the utility of manometric testing. We retrospectively reviewed tracings obtained between November 2005 and May 2008. A total of 298 patients (86% women; average age 52 years) were included. The main indications were incontinence (51%) and constipation (42%). Patients suffering from incontinence were older and had lower resting and squeeze pressure compared to continent patients. However, the discriminative power of manometric pressure data was poor, with low sensitivity and specificity. An abnormal straining pattern suggesting dyssynergic defecation was seen in 43% of constipated patients compared to 13% of patients with fecal incontinence. A concordance between manometric patterns and the balloon expulsion test was seen in 72%. The low sensitivity and specificity of manometric parameters does not support the routine use of anorectal manometry in patients with defecation disorders.

Differences in the pressures of canal anal and rectal sensitivity in patients with fecal incontinence, chronic constipation and healthy subjects

“…On the other hand, the distribution by sexes of the control group homogenous, both AI and CC are more frequent in women (14), although in our study females only had an increased probability of having CC.…”

“…With respect to the manometric findings of the patients with AI: the resting pressure, ACL and SMP are diminished compared to the other groups as described by other authors (12,14,18). There is also a more impaired rectal sensation.…”

“…This fact can justify the greater age found in the group of patients with AI with respect to the CC group and healthy subjects, being an independent risk factor, but we are conscious of the limitations imposed by not beingable to have a control group with similar ages to those of the patients with AI. In fact limited information about normal values has been published, and in most studies a healthy control group is typically composed with young subjects with an equal distribution of men and women (14).…”

“…Later from a resting period between 20-30 seconds the balloon was inflated again to the following volume (14). The volume of initial inflation was 20 cc.…”

“…Also rectal sensitivity values differ according to sex, that the urge sensation oscillates between 60-160 ml in women and 70-190 in men and MTV in 90-270 ml in women and 140-270 ml in men (12). Although expert and professional organizations recommend the use of the anorectal manometry (13), some authors question its utility since sensitivity and specificity are not superior to that found in the rectal digital examination (14,15).…”