High and intermediate imperforate anus: results after surgical correction with special respect to internal sphincter function.

Embryologically a fistula in an anorectal malformation can be regarded as an ectopic anus. Since 1984 the so-called fistula has been saved and used as the new anal canal in the surgical reconstruction of 48 patients with high or intermediate imperforate anus. A positive rectoanal inhibitory reflex indicating internal sphincter function was recorded in 32 of 43 patients investigated with anorectal manometry. These patients showed significantly better anal continence. It is concluded that there is an internal sphincter "anlage" in the fistulous connection from the bowel to the urogenital tract. Internal sphincter function can be obtained in the majority of the patients, which seems advantageous for their anal function.