Respective value of pudendal nerve terminal motor latency and anal sphincter electromyography in neurogenic fecal incontinence

Abstract

Fecal incontinence may be related to a neurogenic injury. Electrodiagnostic tests including pudendal nerve terminal motor latency (PNTML) and external anal sphincter electromyography (AEMG) have been proposed to reveal anal nerve damage. The aim of this study was to assess the respective value of PNTML and AEMG in the diagnosis of fecal incontinence. This study included 80 women (range 23–85 years) with fecal incontinence secondary to obstetrical and/or surgical trauma. They were evaluated by performing PNTML and AEMG. The electrophysiological results were compared and interpreted in the light of anorectal manometry (ARM) results. Electrodiagnostic test abnormalities were found in 64 of 80 patients (80%), including 28 patients with abnormal results for both tests and 36 patients with only one abnormal test. Overall, a neurogenic AEMG pattern was found in 64% of patients and a prolonged PNTML in 51%. No correlation was found between PNTML value and either AEMG grade or ARM parameters, while AEMG grade strongly correlated with squeeze pressure measured by ARM. This study showed that AEMG and PNTML did not give redundant information and allowed to explicit the mechanisms of neurogenic fecal incontinence. We found that AEMG was more sensitive and more closely related to the anal functional status (ARM parameters) than PNTML. These electrodiagnostic tests, particularly AEMG as performed in everyday practice, are useful in the assessment of neurogenic fecal incontinence.