Comparative study of anal acoustic reflectometry and anal manometry in the assessment of faecal incontinence

Anal acoustic reflectometry (AAR) is a reproducible technique providing a novel physiological assessment of anal sphincter function. It may have advantages over conventional anal manometry. The aims of this study were to determine the ability of AAR and anal manometry to identify changes in anal sphincter function in patients with faecal incontinence (FI) and to relate these changes to the severity of FI.

Women with FI underwent assessment with AAR and anal manometry. All patients completed the Vaizey FI questionnaire and were classified according to symptom type (urge, passive or mixed) and integrity of the anal sphincters. The ability of AAR and anal manometry to correlate with symptom severity was evaluated. AAR was compared with anal manometry in detecting differences in anal sphincter function between symptomatic subgroups, and patients with and without a sphincter defect.

One hundred women with FI were included in the study. The AAR variables opening pressure, opening elastance, closing elastance and squeeze opening pressure correlated with symptom severity, whereas the manometric measurements maximum resting pressure and maximum squeeze pressure did not. Unlike anal manometry, AAR was able to detect differences in anal sphincter function between different symptomatic subgroups. [corrected]. An anal sphincter defect was not associated with a significant change in anal sphincter function determined by either AAR or anal manometry.

In the assessment of women with FI, AAR variables correlated with symptom severity and could distinguish between different symptomatic subgroups. AAR may help to guide management in these patients.