STRIATED ANAL-SPHINCTER ELECTROMYOGRAPHY IN IDIOPATHIC FECAL INCONTINENCE

PURPOSE: This study was designed to determine the importance of innervation of striated anal sphincters, one of the most important structures in idiopathic fecal incontinence. METHODS: Forty-three idiopathic, fecally incontinent patients (40 women and 3 men; mean age, 57.2 +/- 11 (range, 33-77) years) underwent anorectal manometry and sphincteric electromyography. On the basis of electromyographic findings, patients were subdivided into three groups: Group A consisted of 21 patients with normal electromyography; Group B consisted of 14 patients with moderate denervation; Group C consisted of 8 patients with severe denervation. Manometric results from the patients were compared with those from 15 healthy subjects (8 women and 7 men; mean age, 35 +/- 12 (range, 15-55) years). RESULTS: Incontinent patients had a shorter anal canal (P = 0.005), and anal canal pressure was lower at rest (P < 0.001), at contraction (P < 0.001), and at coughing (P < 0.001); rectal distention and rectal compliance were reduced (maximum tolerated volume, P < 0.003; compliance at 200 ml, P = 0.03; at 250, P < 0.005; at 300 ml, P = 0.03). No statistically significant differences were found between the manometric results of the three different groups of patients. A statistically significant linear correlation was reached by comparing the clinical severity of fecal incontinence with age (P = 0.02) and some other manometric parameters: the pressure of the anal canal at rest (P < 0.001) and at contraction (P < 0.01); rectal compliance at 50 ml (P = 0.03), 100 ml (P = 0.004), and 150 ml (P = 0.004). CONCLUSION: Clinical severity of fecal incontinence is correlated with some manometric parameters. Severity of denervation of the anal striated sphincters does not appear to influence severity of fecal incontinence.