Horseshoe abscesses and fistulas: how are we doing?

Various surgical treatments exist for horseshoe abscesses and fistulae, including posterior midline sphincterotomy, catheter drainage, cutting and draining setons, and advancement flaps. The aim of this study was to evaluate the long-term results of patients treated for these complex anorectal problems.

A retrospective review was undertaken of patients with a diagnosis of horseshoe abscess, horseshoe fistula, postanal space abscess, or postanal space fistula from 1990 to 2001. Long-term follow-up was accomplished by telephone questionnaire.

Thirty-one patients were identified, of whom 17 (54.8%) had a diagnosis of Crohn disease. The diagnosis at presentation included unilateral (ischiorectal) abscess (32.3%), bilateral horseshoe abscess (51.6%), bilateral horseshoe fistula (9.7%), and postanal space abscess (6.4%). Endoanal ultrasonography was used during the preoperative evaluation in 11 patients (35.5%). After referral to our institution, patients underwent a median of four operations (range, 1 to 9). At a mean follow-up of 49.3 months, 60.7% of patients had either healed perineal disease or were asymptomatic with controlled disease. Patients who had a posterior midline sphincterotomy were more likely to be asymptomatic (P=.047). Patients who had a diagnosis of Crohn disease required more operations than those without Crohn disease (3 vs 1.86, P=.02). Only patients who had a diagnosis of Crohn disease had a stoma at their last follow-up (4 of 17, 23.5% vs 0 of 11, 0%; P=.05).

Patients with horseshoe abscess or fistulae often require multiple operations for treatment but can expect reasonable rates of long-term success in controlling or curing their disease. Those who undergo posterior midline sphincterotomy seem to benefit with higher rates of improved symptoms. Patients with a diagnosis of Crohn disease may fare less well. The role of endoanal ultrasonography in directing therapy remains to be defined.