[The seton in the treatment of trans-sphincteric anal fistulas].

In most patients anal fistulas are of the intersphincteric type (Parks' classification). Treatment consists of simple fistulotomy. 10% of those with an anal fistula have the more complicated trans-sphincteric type. The treatment of such a fistula by primary fistulotomy is associated with a high rate of incontinence. A technique to avoid this complication is the use of the seton for gradual transection of the sphincteric fibers. 21 of 53 patients with anal fistula had a trans-sphincteric fistula, and all of them were treated with setons. Hospital stay was 2 days and was followed by 2-4 outpatient visits. 17 patients (85%) underwent the procedure without any complications and were cured. 3 (15%) had minor problems with continence, of whom 2 required emergency operation. In no case did the fistula recur. We find that the use of the seton after partial fistulotomy for complicated anal fistulas reduces the rate of incontinence caused by sphincteric transection and has a very low recurrence rate.