Background: Because of the disability associated with surgery for anal fissure and the risk of incontinence, medical alternatives for surgery have been sought. Most recently, pharmacologic methods that relax the anal smooth muscle, to accomplish reversibly what occurs in surgery, have been used to obtain fissure healing.
Objectives: To assess the efficacy and morbidity of various medical therapies for anal fissure.
Search strategy: Search terms include "anal fissure randomized".
Selection criteria: Studies in which participants were randomized to a non-surgical therapy for anal fissure. Comparison groups may include an operative procedure, an alternate medical therapy or placebo. Chronic fissure, acute fissure and fissure in children are included in the review. Atypical fissures associated with inflammatory bowel disease or cancer or anal infection are excluded.
Data collection and analysis: Data were abstracted from published reports and meeting abstracts, assessing method of randomization, blinding, "intention to treat" and drop-outs, therapies, supportive measures (applied to both groups), dosing and frequency and cross-overs. Dichotomous outcome measures included Non-healing of the fissure (a combination of persistence and recurrence), and Adverse events (including incontinence, headache, infection, anaphylaxis). Continuous outcome measures included measures of pain relief and anorectal manometry.
Main results: 21 different comparisons of the ability of medical therapies to heal anal fissure have been reported in 31 RCTs. Nine agents were used (nitroglycerin ointment (GTN), isosorbide dinitrate, Botulinum toxin (Botox), diltiazem, nifedipine (Calcium channel blockers or Cachablos), hydrocortisone, lignocaine, bran, placebo) as well as anal dilators and surgical sphincterotomy. When two studies are excluded from analysis due to quality concerns, the significance disappears in the three main analyses: GTN vs. placebo group (0.78; 0.56-1.08), in children (0.96; 0.48-1.92) and adults (0.73; 0.50-1.07). That is, GTN was, in this modified analysis, not significantly better than placebo in curing anal fissure. Cachablos were not tested against placebo, but in a comparison to GTN, Cachablo was equivalent in its ability to cure fissure (odds ratio 0.66; 0.22-2.01). Botox, in a meta-analysis of two studies compared to placebo, showed no significant advantage in efficacy (0.75; 0.32-1.77), and in a comparison to GTN analyzing two studies, was also not significantly better than GTN (0.48; 0.21-1.10).
Reviewer's conclusions: Medical therapy for chronic anal fissure, acute fissure and fissure in children may be applied with a chance of cure that is only marginally better than placebo, and, for chronic fissure in adults, far less effective than surgery.