The use of a staged drainage seton for the treatment of anal fistulae or fistulous abscesses

Abstract

Purpose: The aim of this retrospective study was to evaluate the rate of recurrence and incontinence after the treatment of fistulae or fistulous abscesses by using the staged drainage seton method.

Methods: According to the condition, a drainage seton alone or a drainage seton combined with internal opening (IO) closure and relocation of the seton was used. After a period of time, the seton was changed with 3-0 nylon; then, after another period of time, the authors terminated the treatment by removing the 3-0 nylon. Telephone interviews were used for follow-up. The following were evaluated: the relationship between the type of fistula and recurrence; the relationship between the type of fistula and the period of treatment; the relationship between the recurrence and presence of abscess; the relationship between IO closure and recurrence; the relationship between the period of seton change and recurrence; reported continence for flatus, liquid stool, and solid stool.

Results: The recurrence rate of fistulae or suppuration was 6.5%, but for cases of horseshoe extension, the recurrence rate was 57.1%. The rate of recurrence was related to the type of fistula (P = 0.001). Incontinence developed in 3.8% of the cases. No statistically significant relationship was found between the rate of recurrence and the presence of an abscess or between the closure of the IO and the period of seton change or removal.

Conclusion: In the treatment of anal fistulae or fistulous abscesses, the use of a staged drainage seton can reduce the rate of recurrence and incontinence.

Keywords: Fistula; Perianal abscess; Seton; Surgical drainage.

Fig. 1

A metallic probe was inserted gently from the external to the internal opening of the fistula. Meticulous care should be taken not to make an iatrogenic tract or opening because of forceful insertion.

Fig. 2

A gauze was inserted through the fistula tract for curettage. Epithelization of the fistula tract can be destroyed by moving the gauze back and forth several times.

Fig. 3

A rubber band was inserted through the fistula tract as a seton. In this procedure, a 5-mm rubber band was used.

Fig. 4

A partial internal sphincterotomy from the internal to the external opening was performed.

Fig. 5

The incised internal opening and the internal anal sphincter were repaired with interrupt suture at least two layers of absorbable suture material (4-0 Surgisorb). With this procedure, re-routing of the fistula through the intersphincteric plane was accomplished.

Fig. 6

Schematic view of the rerouting procedure. The drawing on the right shows insertion of the seton through the transsphincteric fistulous tract, and that on the left shows completion of the rerouting procedure with repair of the incised internal anal sphincter and closure of the internal opening.

Fig. 7

Completion of the operation. The seton was tied loosely for drainage. The external opening of the fistula was marsualized with absorbable suture material.