The surgical management of fistula-in-ano in a specialist colorectal unit.

INTRODUCTION: Fistula-in-ano can be associated with a number of conditions, including Crohn's disease. The majority, however, are classified as idiopathic or cryptoglandular. The aim of this study was to review the outcome of surgical management of fistula-in-ano in a specialist colorectal unit.

MATERIALS AND METHODS: One hundred and four consecutive patients underwent surgery for anal fistulae between 1st January 2000 and December 2004. Data was analysed in two main groups, according to the aetiology, cryptoglandular (n = 86) and Crohn's disease (n = 18). Follow-up data was available on 91 patients.

RESULTS: In the cryptoglandular group, 62 patients had an inter-sphincteric tract, of which 48 underwent a single-stage fistulotomy. Of those patients with a trans-sphincteric tract, six patients underwent a single-stage fistulotomy, 13 had a seton and staged fistulotomy. Follow-up data revealed that two fistulae recurred. The median number of procedures in this group was 1 (range 1-3). There was a significant difference in the inpatient stay depending of Park's classification (p = 0.001). In the Crohn's group, three patients with an inter-sphincteric tract underwent a single-stage fistulotomy, two patients with a trans-sphincteric tract had single-stage fistulotomy, and five required a loose seton and staged fistulotomy. Eight patients had multiple fistulae which required long-term setons. Four patients from this group eventually required proctectomy. In the Crohn's group, there was a significantly increased complexity of surgery and higher recurrence. This was reflected in an increased inpatient length of stay and a greater reliance on imaging (p = 0.001). The median number of procedures in this group was 3 (range 1-5).

DISCUSSION: The majority of cryptoglandular fistula-in-ano were treated by primary fistulotomy or staged fistulotomy with a loose seton. This was associated with a low recurrence rate and low rates of faecal incontinence. There was a low reliance on imaging techniques in this group. However, we would urge caution when dealing with fistula-in-ano related to Crohn's disease. In this group of patients, the fistulae tended to be more complex and require additional imaging and multiple procedures.