3D pelvic floor ultrasound findings and severity of anal incontinence

The aim of our study was to determine the association between the severity of anal incontinence and levator ani deficiency, anal sphincter defects, anorectal angle, and colonic motility abnormalities.

This was a retrospective study. Subjects were categorized into three groups: normal, minor anal incontinence, and major anal incontinence according to their answers to the PFDI-20 questionnaire. 3D endovaginal ultrasound was utilized to assess levator ani muscle and the anorectal angle. Levator ani muscle subdivisions were scored based on avulsion from the pubic bone and muscle thickness, based on our previous work. 3D endoanal ultrasound was utilized to assess anal sphincters. Colonic motility abnormalities were defined as diarrhea, constipation or both.

Ninety-seven patients were included in the analysis: 45 with major anal incontinence, 29 with minor anal incontinence, and 23 continent women. On multivariate logistic regression, sphincter defect, anorectal angle, and colonic motility abnormalities were associated with anal incontinence severity. Women with an external anal sphincter defect had a 20.36-fold chance of having severe anal incontinence compared with patients with no defect (OR 20.36, 95 % CI 5.4, 76.6); those with both defective sphincters had a 102.5-fold chance of having severe anal incontinence (OR 102.5, 95 % CI 10.2, >999). Anorectal angle ≥170° was significantly associated with the severity of anal incontinence (OR = 4.07, 95 % CI 1.53, 10.79), as was the presence of colonic mobility abnormality (OR 5.31, 95 % CI 1.86, 15.19).

3D pelvic floor ultrasound can be an efficient tool for anal incontinence evaluation in women. Anal sphincter defects, colonic motility abnormalities, and anorectal angle were associated with the severity of anal incontinence. While there was a trend toward worsening levator ani deficiency among those with major anal incontinence, this did not reach statistical significance.