Electrodiagnostic evaluation of fecal incontinence

Abstract

The aim of this study was to assess the utility of electrodiagnostic testing (EDT) for the evaluation of fecal incontinence (FI). Over a 5-year period, 225 patients (174 females) with FI were prospectively studied with anal manometry, anal ultrasonography, anal electromyography (AEMG), and pudendal nerve terminal motor latency (PNTML) assessment. The mean age was 60 (range 12-94) years. Causes of FI identified by clinical evaluation were obstetric injuries (45), rectal prolapse (43), iatrogenic or other trauma (42), neurologic disease (23), and idiopathic (72). EDT revealed abnormalities in 76% of patients. The incidence of pudendal neuropathy (PN) was 36% (bilateral 21%, unilateral 15%). Patients with PN were older than were those with normal PNTML (mean 71 vs. 63 years; P < 0.002). No relationship between squeeze pressure and PN could be demonstrated (P = 0.9). Reduced motor unit potential (MUP) recruitment on AEMG was present in 60% and was associated with decreased squeeze pressure (P < 0.001) and increased MUP polyphasia (P < 0.001). Concurrence of AEMG and anal ultrasonographic findings was observed in 35 of 41 patients (84%). Defects were overlooked in one study but identified by the other on three occasions, each. Moreover, 8 of 22 patients with demonstrated sphincter defects had unsuspected PN or extensive sphincter injury on AEMG that precluded sphincter repair. In conclusion, EDT proved to be a valuable tool in the evaluation and subsequent treatment of patients with FI.

Neurophysiological testing in anorectal disorders

“…This approach owes its popularity to a number of studies reporting prolonged TMLs in various anorectal disorders, 101,121 such as fecal incontinence, 18,48,58,62,94,120,129,130,142,150,162,166 obstetrical lesions, 141,144,146,152,153,155 perineal descent, 6,51,53,62,77,143 or even constipation. 162,163 Evidence of pudendal/ anal neuropathy, as shown by a prolonged TML, was proposed as a predictive factor for the clinical outcome of biofeedback therapy 67 or surgical repair 13,39,145 of pelvic floor disturbances, even in case of unilateral neuropathy.…”

“…Imaging, for example, anal endosonography, may be preferred to needle EMG in the diagnosis of anal sphincter defects. 23,63 However, anorectal manometry and needle EMG appear to be complementary techniques for the assessment of fecal incontinence, EMG interference pattern being correlated with squeeze pressure 18,149,174 but providing additional information regarding the presence of a neuropathic process. 32 …”

Anal sphincteric neurogenic injury in asymptomatic nulliparous women and fecal incontinence

“…However, anal sphincter EMG is not widely available and infrequently used, mainly when neurogenic injury is suspected, in clinical practice. Also, based on limited data that suggest that anal sphincter denervation predicts poorer outcome after anal sphincteroplasty (10,21), anal sphincter EMG should also be considered before surgery.…”

Messmethoden zur Diagnose der fäkalen Inkontinenz

“…Die Nadel-EMG-Untersuchung wurde zur Identifikation von Sphinkterdefekten eingesetzt, ist aber wegen ihrer Schmerzhaftigkeit, des Infektionsrisikos und der höheren Sensitivität der endoanalen Ultraschalluntersuchung durch letztere weitgehend ersetzt worden [49]. Andererseits korreliert die EMGAktivität, die von einer analen Stöpselelektrode abgeleitet wird, sehr gut mit der Externusaktivität [69], sodass man diesen Parameter zur Kontrolle bei der Biofeedback-Therapie verwenden kann.…”