Drain fistulography: Radiological sphincter identification in high anal fistulae

To warrant permanent surgical cure of high anal fistulae, while avoiding at the same time faecal incontinence due to inadvertent division of the puborectalis muscle, distinction between a trans- and suprasphincteric fistula track is essential. This differentiation is often crucial, since digital-rectal palpation and conventional fistulography tend to be unreliable. Therefore we developed a radiological technique of imaging the anorectal fistulous track, 'drain fistulography'. After silicon drainage of the fistula the contrast-visualization of anal canal, rectum and fistula drain allows to assess the topographic relation between fistula and anal sphincters as well as the sphincteric functional component above the fistula. A transsphincteric fistula track was demonstrated in 7 of 8 patients (5 with recurrent fistulae) by means of 'drain fistulography', permitting complete laying open of each fistula in a second operation. In one patient a supraphincteric fistula track was found and a 'mucosal flap repair' was carried out. After a mean observation time of 53 months all patients are perfectly continent and free of recurrence. The method of 'drain fistulography' is a valuable diagnostic tool to select the appropriate definitive surgical procedure in the treatment of high anal fistulae. (orig.)