Cutting seton without preliminary internal sphincterotomy in management of complex high fistula-in-ano

The traditional treatment of a complex high fistula-in-ano by internal sphincterotomy and insertion of a cutting seton carries a risk of fecal incontinence. We have assessed the functional impact of treating patients with a complex fistula-in-ano by a cutting seton fistulotomy technique that preserves the internal sphincter.

The operative steps consisted of initial eradication of sepsis, identification of the internal and external openings of the fistula tract, excision of the fistula tract with anal canal mucosa, and insertion of a cutting silk seton around both the internal and external sphincters. In this way open drainage of the intersphincteric space was avoided, and integrity of the internal sphincter was maintained. Functional outcome following treatment with this technique, with regard to fistula eradication and effect on fecal continence was assessed in 27 patients (15 males) who were treated during a six-year period. Twenty-three patients (85 percent) had a history of previous fistula surgery.

The fistula was cured in 26 patients (96 percent) with no reports of altered continence at the time of discharge from outpatient review. Recurrence developed in one patient (4 percent) in whom hidradenitis suppurativa was subsequently diagnosed. All four patients with Crohn's disease had their fistulas eradicated; three (75 percent) have subsequently undergone proctectomy for severe perianal and rectal Crohn's involvement. Long-term follow-up revealed three patients (19 percent, all rectovaginal fistulas) who experienced a deterioration in continence after discharge.

Although this procedure may not be appropriate for rectovaginal fistulas, the data suggest that cutting setons are effective in treating complex fistula-in-ano, including those that have failed to respond to other forms of surgery. Avoidance of preliminary internal sphincterotomy may prevent deterioration in continence.