A computerised vector manometry study of the so-called ectopic anus

There are several totally different definitions of the so-called ectopic an us. To determine whether computerized eight-channel manometry helps to defi ne the entity of the ectopic anus, ten patients (nine females) were operate d upon for an ectopic anus by the anal transposition technique (perineal pu ll-through procedure). Besides the software-supported manometric data, the qualitative imaging analysis was of interest. We calculated the factor by w hich the pressure of the three ventrally-located segments was lower than th e mean segmental pressure at this part of the anal canal. The results were compared to standard age-related values established in a former study in 10 0 children. Besides pre- and postoperative manometry, barium roentgenograms were obtained. The anal-canal length at rest in the ectopic anus was signi ficantly (P < 0.0001) longer. The segmental asymmetry index in the lower an al canal (LAC) was increased, but not significantly. The pressure in the ve ntral segments of the LAC was significantly (P < 0.0001) decreased and was less than one-half of the mean segmental pressure in this zone. We found a significant correlation between the degree of anterior displacement and the factor by which the ventrally-located pressure values were decreased. Post operatively, this factor increased significantly. From a functional point o f view, the definition of the ectopic anus includes a deficient high-pressu re zone ventrally in the LAG. The LAG seems to run out or nearly out of the ventral sphincteric issue to end ectopically on the perineal surface.