Unsuspected sphincter damage following childbirth revealed by anal endosonography.

Anal endosonography was performed in 62 consecutive patients with incontinence of flatus or faeces following obstetric trauma, and in 18 parous controls. Of the incontinent group, 90% had defects in the external sphincter, 65% in the internal sphincter and 44% disruption of the perineal body, compared with none of the controls. This triad of lesions is pathognomonic of obstetric trauma. Anal endosonography revealed a higher prevalence of sphincter damage than expected from anorectal physiology tests, and therefore has a role in screening patients following complicated or difficult deliveries.