Meta-analysis of randomized clinical trials comparing drainage alone vs primary sphincter-cutting procedures for anorectal abscess-fistula

Background and aim: Concurrent definitive treatment of underlying fistulas from infected anal glands at the time when the anorectal abscesses are drained is controversial as this is associated with a higher incidence of faecal incontinence, failure and recurrence. This meta-analysis was conducted to determine the merits of drainage alone vs primary sphincter-cutting procedures (which includes fistulotomy and fistulectomy) for anorectal abscess-fistula. Methods: Medline, Embase and Cochrane Central Register of Controlled Trials database searches identified all randomized controlled trials using the keywords: anorectal abscess, anal sepsis, drainage, fistulotomy, fistulectomy or surgery from 1966 to 2004. The outcome variables analysed were recurrence, faecal continence and wound-healing times. Results: Five trials were considered suitable for the meta-analysis, with a total of 405 patients. Sphincter-cutting procedures for anorectal abscesses resulted in 83% reduction in recurrence rate [relative risk (RR) 0.17, 95% confidence interval (CI) 0.09-0.32, p < 0.001]. However, there was a tendency to a higher risk of faecal incontinence to flatus and soiling when primary sphincter-cutting procedure was performed (RR 2.46, 95% CI 0.75-8.06, p=0.140). Conclusion: There is no conclusive evidence if simple drainage or sphincter-cutting procedure is better in the treatment of anorectal abscess-fistula.