Treatment procedures for anal fistulous cryptoglandular abscess--how to get the best results.

Background: Up to date anal fistulous cryptoglandular abscess is a subject of controversial scientific discussions and the number of medico legal cases dealing with treatment procedures is growing . In principal, there is a dispute whether it is reasonable to perform a primary fistulotomy at the time of abscess drainage or to wait for a secondary fistulotomy. The purpose of this study was to compare studies focussing on the treatment of anal fistulous abscess with regard to different treatment procedures, their outcome (recurrence, incontinence, follow-up) and factors influencing outcome (primary or recurrent fistulous abscess, comorbidity, exclusion criteria, anaesthesia, microbiology, antibiotics, search for internal opening, classification).

Methods: A Medline search included the terms: fistulous abscess, anal abscess, horseshoe abscess, anorectal sepsis, and perianal infection/abscess.

Results: In 63 (1964-2004) studies we found 35 different treatment methods: the most often used procedures were incision and drainage (I+D; n = 35) and incision and drainage and primary fistulotomy (I+D+pF; n = 23). Only in ten studies the treatment has been restricted for primary anal fistulous abscess; the remaining studies investigated primary and recurrent anal fistulous abscess. There was a considerable lack of information on morbidity, microbiology, and exclusion criteria. In only 16/63 studies patients were routinely diagnosed and treated under general anaesthesia. We found nine different classifications of fistulous abscess. There is a wide range of recurrence after different treatment procedures: up to 88% after I+D and 21% after I+D+pF. The incontinence rate after I+D ranged from 0-26%, after I+D+pF 0-52%. However, in many studies there was no information on incontinence available.

Conclusions: A true comparison of different treatment methods is not available. This is mainly due to either a lack of information on important factors influencing outcome, even unclear definitions in some instances. Recent randomized studies have been criticized for missing information and flaws in the randomization procedure. The choice of treatment, e.g., primary or secondary fistulotomy, depends on the clinical experience of the surgeon on duty, the hospital structure (staff, equipment, and anaesthesia), the patient's history and the local anatomical circumstances. On the basis of up to date knowledge there is no reason to condemn primary or secondary fistulotomy without more clinical studies and without knowing the individual situation.