Assessment of third degree tears using three-dimensional anal endosonography with combined anal manometry: a novel technique.

Three-dimensional anal endosonography has enabled sagittal and coronal reconstructions of the anal canal to be matched with longitudinal pressure data, to present a combined picture of structure and function. This novel technique has been applied to a group of women with a clinical diagnosis of a third degree tear. Endosonography showed that only 68% of women had ultrasound evidence of sphincter damage. Anal canal anatomy and pressure profile did not differ significantly between those with and those without sphincter damage, but the anterior external anal sphincter and the puborectalis tended to be shorter and the pressures were lower in those with sphincter disruption.