Anal fissure and lateral internal sphincterotomy: An overview

Anal fissure has a very large number of treatment options. The choice is difficult. To assist in this choice, presented herein is a summary of a systematic review and meta-analysis of all published treatments for anal fissure that have been studied in randomized controlled trials up through 2016. The review is divided into those studies that compared two or more surgical procedures and those that had at least one arm that was nonsurgical. Studies were further categorized by the specific interventions and comparisons. The outcome assessed was the inverse of sustained cure of the fissure, i.e., treatment failure. In addition, the harms of treatment assessed were headache and anal incontinence. Risk of bias was assessed for each study and the strength of the evidence of each comparison was assessed using Grading of Recommendations, Assessment, Development and Evaluations (GRADE). A total of 148 eligible trials were found and assessed, 31 in the surgical group (2606 patients) and 117 in the nonsurgical group (9456 patients). There were 14 different operations described in the surgical group and 29 different nonsurgical treatments in the nonsurgical group along with partial lateral internal sphincterotomy (LIS). There were 61 different comparisons. Of these, 47 were reported in two or fewer studies, usually with quite small populations. The largest single comparison was glyceryl trinitrate (GTN) versus control with 19 studies. GTN was more effective than control in terms of sustained cure (odds ratio = 0.68; 95% confidence interval = 0.63–0.77) but the quality of evidence was very poor due to severe heterogeneity and risk of bias due to inadequate clinical follow-up. The only comparison to have a high GRADE quality of evidence was a subgroup analysis of LIS versus any medical therapy, with outcome of treatment failure (0.12; 0.07–0.21) and mild incontinence (4.41; 1.97–9.87) assessed after at least 6 months from surgery. There were 12 studies in this analysis, the medical therapy being GTN in 6, Botox in 5, and calcium channel blocker (CCB) in 1. Most of the other analyses were downgraded in GRADE due to imprecision, i.e., too few or too small studies, and significant heterogeneity in almost all other comparisons with more than six studies. LIS is superior to nonsurgical therapies in achieving sustained cure of fissure with an increased risk of mild incontinence, usually meaning flatus. CCBs were more effective than GTN and had less risk of headache, but with only a low quality of evidence. Anal incontinence, once thought to be a frequent risk with LIS, was found in various subgroups in this review to have a risk between 3.4 and 4.4%. Among the surgical studies, manual anal stretch (Lord procedure) performed worse than LIS in the treatment of chronic anal fissure in adults. For those patients requiring surgery for anal fissure, open LIS and closed LIS appear to be equally efficacious, with a moderate GRADE quality of evidence. Most other GRADE evaluations of procedures were low to very low, due mostly to imprecision.