RESUMEN
This is a prospective randomized trial aiming to compare the effect of open lateral internal sphincterotomy versus Botulinum toxin injection in the treatment of chronic anal fissure. Thirty patients diagnosed as suffering from chronic anal fissure were randomly allocated into two groups. In the surgical sphincterotomy group [n =15] lateral internal sphincterotomy was done. In the Botulinum toxin group [n = 15] 20 U of type A botulinum toxin was injected into the internal anal sphincter. The injection was repeated two months later of complete healing was not accomplished. The patients were re-examined by inspection and re-evaluated for symptoms at 2, 6 and 12 months. Two months after treatment, the healing rate was 60% [9/15] in the BT group, and 93.5% [14/15] in the LIS group [p=0.031]. In the BT group 6 patients were offered a second injection at the second month. Six months after treatment one patient of the LIS group developed recurrences. Therefore, at six months the healing rate was 73.3% [11/15] in the BT group, compared to 86.7% [13/15] in the LIS group [p=0.36]. By 12 months post treatment, the healing rate remained stable in the LIS group 86.7% [13/15], while three patients in the BT group developed recurrence, resulting in an overall success rate of 53.3% [8/15] [P=0.046]. The return to daily activity was significantly longer in the LIS group [12.8 +/- 4.6 days] vs. [1 day] in the BT group [p<0.0001]. The incidence of complications in the sphincterotomy [4 cases of transient partial incontinence] group was significant as compared with none in the BT group [p=0.32]. In comparing the results of the two treatment modalities, BT injection was found to be inferior to LIS regarding the healing rates. On the other hand the BT therapy is easy to perform, can be done as an outpatient procedure, and associated with less complication. Considering these factors BT therapy might be valuable in selected patients with high surgical risks, or high incidence of future incontinence