Sensitivity and specificity of multichannel surface electromyography in diagnosing fecal incontinence.

BACKGROUND: Assessment of the neurocontrol of the external anal sphincter has long been restricted to investigating patients by invasive tools. Less invasive techniques have been regarded less suitable for diagnosis.

OBJECTIVE: The aim was to develop a surface electromyography-based algorithm to facilitate fecal incontinence diagnosis, and to assess its sensitivity and specificity.

DESIGN: Data analysis from a single center prospective study.

PATIENTS: All patients from colorectal surgery office were considered. They underwent a structured interview, a general physical and proctologic examination. Patients with diagnosed fecal incontinence (Fecal Incontinence Severity Index >10) were included into the study group. The control group consisted of healthy volunteers that scored 5 or less and had negative history and physical exam. Both groups underwent the same tests (rectoscopy, anorectal manometry, transanal ultrasonography, multichannel surface electromyography and assessment of anal reflexes).

METHODS: EMG results were analyzed to find parameters that would facilitate fecal incontinence diagnosis.

OUTCOME MEASURES: Sensitivity and specificity of surface electromyography, to diagnose fecal incontinence, were assessed.

RESULTS: A total of 49 patients were included in the study group (mean age ± SD 58.9 ± 13.8). The control group (n = 49) gender matched the study group (mean age ± SD 45.4 ± 15.1). The constructed classification tree, based on surface electromyography results, correctly classified 97% of cases. Thee sensitivity and specificity of this classification tree, to diagnose FI, was 96% and 98% respectively.

LIMITATIONS: The age of women in the control group differs significantly from mean age of other groups.

CONCLUSIONS: Surface electromyography is an good tool to facilitate diagnosing of fecal incontinence.