Use of Anal Acoustic Reflectometry in the Evaluation of Men With Passive Fecal Leakage.

BACKGROUND: Men with passive fecal leakage represent a distinct clinical entity in which the pathophysiology remains unclear. Standard anorectal investigations fail to demonstrate consistent abnormalities in this group. Anal acoustic reflectometry is a new test of anal sphincter function with greater sensitivity and discriminatory ability than conventional anal manometry.

OBJECTIVE: The aim of this study was to determine whether men with fecal leakage have an abnormality in anal sphincter function that is detectable by anal acoustic reflectometry.

DESIGN: This was an age-matched study of continent and incontinent men.

SETTINGS: The study was conducted at a university teaching hospital.

PATIENTS: Male patients with isolated symptoms of fecal leakage were recruited. Anal acoustic reflectometry, followed by conventional anal manometry, was performed. Results were then compared with those from an age-matched group of men with no symptoms of anal incontinence or anorectal pathology.

MAIN OUTCOME MEASURES: Variables measured with anal acoustic reflectometry and anal manometry in the incontinent and continent men were compared.

RESULTS: Thirty subjects were recruited, of whom 15 were men with fecal leakage and 15 were continent men. There was a significantly higher incidence of previous anorectal surgery in the men with leakage. The anal acoustic reflectometry variables of opening and closing pressure were significantly lower in leakers compared with continent subjects (p = 0.003 and p = 0.001). Hysteresis was significantly greater in the male leaker group (p = 0.026). No difference was seen in anal manometry.

LIMITATIONS: With a larger sample size, the effect of previous anorectal surgery and the presence of an anal sphincter defect could be clarified.

CONCLUSIONS: Anal acoustic reflectometry is a sensitive test of anal sphincter function and, unlike anal manometry, can discriminate male leakers from continent subjects. An identifiable abnormality has been detected using anal acoustic reflectometry, which may further our understanding of the pathogenesis in this group.