[The mucosal sliding flap in the treatment of supra and high trans-sphincteric anal fistula].

Since 1989 we have operated upon 28 patients for trans- or suprasphincteric fistula, using the mucosal sliding flap: After injection of a vasoconstrictory agent into the submucosal tissue we sparingly excise the inner opening of the fistula just beyond the dentate line. A mucosal flap is then meticulously dissected and used to cover the lesion in the rectum. The flap prevents fecal bacteria from invading the intrasphincteric portion of the fistula. This portion remains intact, and so does the sphincter apparatus. Then we excise the fistulous tract, proceeding from its external opening towards the sphincter muscle. After a mean follow-up of 8.1 months all 28 patients are free of symptoms. Proctoscopy did not reveal persistent or recurrent fistula in any of them.