Predicting anal sphincter defects: the value of clinical examination and manometry

The aims of this study were, firstly, to determine the diagnostic accuracy of an anal incontinence score, clinical examination and anal manometry in identifying anal sphincter defects and, secondly, to establish manometric cut-off values associated with sphincter defects.

One hundred fifty-nine women were evaluated by clinical examination, anal manometry and endoanal ultrasound (EAU). Accuracy measures were calculated, using EAU as the gold standard.

Perineal body length (p = 0.84) and pelvic floor muscle strength (p = 0.10) were not associated with anal sphincter defects. Anal inspection was associated with anal sphincter defects (p < 0.001), although its sensitivity was low at 26%. The sensitivity of digital rectal examination was 67% and the specificity 55%. Cut-off values of manometric findings were set to maximise sensitivity at 30 mm anal length, 54 mm Hg maximum resting pressure, 95 mm Hg maximum squeeze pressure and 53 mm Hg squeeze increment.

Clinical assessment has a poor sensitivity for detecting anal sphincter defects. The proposed manometric cut-off values can be used to either reassure or identify women who may need further assessment by EAU.