What is the relationship between perineal descent and anal mucosal electrosensitivity?

Perineal descent is found in many patients with anorectal disorders. There is now substantial evidence against perineal descent causing damage to the motor axons in the pudendal nerves, but the sensory sequelae of perineal descent have been neglected. The purpose of this study was to establish the relationship between perineal descent and anal sensation.

Perineal position was determined in relation to the bony pelvis by means of defecating proctography. Anal mucosal electrosensitivity was determined by using a constant current generator.

This study demonstrated significant correlations between perineal position at rest and sensitivity in each third of the anal canal in the study group overall. In women studied alone, there were significant correlations between perineal position at rest and at squeeze and anal mucosal electrosensitivity in each third of the anal canal.

We propose that perineal descent traumatizes the pudendal nerves, damaging the large diameter sensory axons. This may be a precursor of motor axon damage or may correlate with the global pelvic sensory loss found in patients with perineal descent and fecal incontinence.