Background: Fecal incontinence [FI] can lead to impaired quality of life and the prevalence is under-reported. The etiology is multifactorial. Careful clinical and neurophysiologic test is used to demonstrate the underlying problem. The objectives of this study are to demonstrate the systematic assessment of the subjects with FI and to compare the investigation findings of the FI group with healthy volunteers.

Materials and Methods: Forty-three subjects with FI and 46 healthy volunteers were evaluated by history taking, physical examination, anorectal manometry, endoanal ultrasound and selective use of pudendal nerve terminal motor latency test [PNTML]. The results were compared.

Results: By anorectal manometry, subjects with FI had significantly shorter high-pressure zone (1.7 vs. 2.3 cm), lower resting anal sphincter pressure (35.2 vs. 64.3 mmHg), lower maximal squeeze pressure (95.7 vs. 203.5 mmHg) and sustained squeeze pressure (74.3 vs. 121.3 mmHg) (p<0.001). Rectal hyposensitivity and hypersensitivity were found in 61% and 23% of the subjects, respectively. Rectoanal inhibitory reflex was absent in 7% and impaired in 23% of subjects. Cough reflex was impaired in 21%. Saline continence test was abnormal in 77% of FI subjects. By endoanal ultrasound, anal sphincter defect or scar was found in 86% of the FI subjects. Anal canal length was found to be significantly shorter in subjects with FI both in the anterior (12.4 vs. 30.4 mm) and posterior (20.1 vs. 35.9 mm) position (p<0.001). In 10 FI subjects that PNTML was performed, 6 subjects demonstrated either unilateral (3) or bilateral (3) pudendal neuropathy. Significant correlation between FISI and posterior anal canal length was observed (r = 0.512, p = 0.015).

Conclusion: Various information of anorectal function and anatomy in subjects with FI can be obtained by systematic approach. This information may be useful forthe management planning and patient education.

Keywords: Anorectal manometry, Endoanal ultrasound, Fecal incontinence, Neurophysiologic test, Pudendal nerve terminal motor latency test