Posterolateral versus lateral internal anal sphincterotomy in the treatment of chronic anal fissure: a randomized controlled trial

Background Lateral internal anal sphincterotomy (LIS) is considered the treatment of choice for chronic anal fissure. This study aimed to compare the outcome of standard LIS and posterolateral internal sphincterotomy (PLIS) at 5 o'clock position as regards healing of anal fissure, improvement in symptoms, and complications. Methods Patients with chronic anal fissure were randomly allocated to one of two groups; group I underwent PLIS and group II underwent LIS. Patients were compared regarding the duration of healing of anal fissure, improvement in anal pain as recorded by visual analogue scale (VAS), complications, particularly fecal incontinence (FI) and changes in the anal pressures. Results Eighty (49 females) patients were included to this trial. The mean age of patients was 35.5 years. The duration of healing was significantly shorter in group I than in group II (4.1 +/- 1.7 vs 5.8 +/- 1.4 weeks; p < 0.0001). Group I achieved significantly lower pain score at 1 month postoperatively than group II (1.1 +/- 0.9 vs 1.7 +/- 0.98; p = 0.005). Two (2.5%) of group I patients and six (10%) of group II patients experienced minor FI postoperatively. The postoperative reduction in the mean resting anal pressure in group I was significantly higher than that in group II. Conclusion Time to complete healing was significantly shorter and pain score was significantly lower after PLIS than after LIS which can be due to more reduction in the resting anal pressure after PLIS. Continence disturbances occurred after PLIS less frequently than after LIS; however, no significant differences between the two techniques were noted.