INCIDENCE OF FISTULAS AFTER DRAINAGE OF ACUTE ANORECTAL ABSCESSES

PURPOSE: The aim of this study was to assess the incidence of anal fis tulas and factors related to this incidence after incision and drainag e of acute cryptoglandular anorectal abscesses. METHODS: Of 170 patien ts without previous anal fistulas, 146 were followed up for an average of 99 (range, 22-187) months after abscess drainage or until a fistul a appeared. RESULTS: Fifty-four (37 percent) patients developed a fist ula, and 15 (10 percent) patients developed a recurrent abscess. The i ncidence of fistulas was higher in females than in males (50 vs. 31 pe rcent; P = 0.0403), especially regarding anterior abscesses (88 vs. 33 percent). Abscesses growing Escherichia coli were more prone to fistu la formation than those growing other bacteria (46 vs. 27 percent; P = 0.0368). CONCLUSION: Incision and drainage alone of acute anorectal a bscesses is recommended, because an unnecessary primary fistulotomy ca n be avoided in more than half of the patients by this approach. For s uperficial anterior abscesses in females, however, primary fistulotomy may be considered.