Horseshoe tract of anal fistula: Bad luck or an avoidable extension? Lessons from 82 cases

Aim The aim of this study was to analyse the characteristics of horseshoe tract formation in anal fistula. Method We retrospectively analysed the data from all consecutive patients who underwent surgery for an anal fistula from November 2004 to March 2011. A horseshoe tract was defined as a circumferential extension connecting both sides of the anorectum. Results During the period of analysis, 1876 patients were operated on for a fistula. Of these, 82 (4.4%) had a horseshoe extension. The majority (72%) were male and the median age was 46 (17-84)years. The primary tract was high transsphincteric in 90% of cases and the primary opening was posterior in 65% of cases. The location of the horseshoe extension was posterior in 66% of cases with spread in the deep perianal space in 62%. In all, 71% were cryptoglandular and 24% were seen in Crohn's disease (20). Of the 62 non-Crohn's patients previous treatment was common and included surgery (42), antibiotics alone (41) and non-steroidal anti-inflammatory drugs (21). Conclusion Horseshoe extension in anal fistula is uncommon. With Crohn's disease excepted, the majority had had previous treatment.