RESUMO
Lateral sphincterotomy is the standard treatment for chronic anal fissure. In recent years, chemical sphincterotomy by several pharmacological agents, i.e. botulinum toxin, nifedipin, glyceryl trinitrate, has been used as alternative treatment. The objective of this study was to compare the results of botulinum toxin injection with lateral sphincterotomy in patients with this condition. In this trial 40 patients were randomized into two groups; 19 patients underwent surgical sphincterotomy and 21 cases were treated with injections of 30 units of botulinum toxin into the internal sphincter at 3 different sites [anterior and lateral]. Patients were followed for up to 6 months to appraise the results. There was no significant difference in sex, age, duration of symptoms and anatomical variability of the disease between two groups. The frequency of healing on follow-up visits in the Botox group at 2 weeks, 2 months, 4 months and 6 months was respectively 33.3%, 76.2%, 85.7% and 85.7% and in the sphincterotomy group it was 47.4%, 89.5%, 100% and 94.7%, respectively [p>0.4]. None of patients in either groups developed fecal incontinence. The frequency of incontinence to flatus in follow-up visits in Botox group was respectively 38.1%, 19%, 4.8% and 0% and in sphincterotomy group it was respectively 63.2%, 31.6%, 26.3% and 21.1%. The difference in the frequency of flatus incontinence was only statistically significant at the 6[th] month visit [p=0.04]. Chemical sphincterotomy with injection of 30 units of Botox into the internal sphincter at 3 sites is an effective treatment for chronic anal fissure and accompanied by fewer complications. It is suggested as the primary step in treatment of chronic fissure with surgical sphincterotomy reserved for refractory cases