The aim of this prospective randomized trial was to compare the effectiveness and morbidity of open and closed sphincterotomy performed as an outpatient procedure under local anesthesia in the treatment of chronic anal fissure.

Eighty patients with chronic anal fissure were treated by open (group 1) or closed lateral internal sphincterotomy (group 2). Clinical and manometric results were recorded at the time of admission and at 1-week, 2-month, 6-month, 1-year, and 2-year followup visits.

Overall healing after 2 years was 92.5% in the open sphincterotomy group and 90% in the closed sphincterotomy group (p > 0.05). Fissures were notably less likely to heal in patients in whom the condition had been present for longer than 12 months and who had a sentinel pile before treatment. At the 2-year revision, incontinence was present in two patients (5%) in the open sphincterotomy group and one patient (2.5%) in the closed sphincterotomy group (p > 0.05). In all cases, the incontinence was mild (<4, Cleveland score). Increased mean resting pressure (113.9 mmHg) was found in patients with anal fissure before treatment compared with the healthy control group (mean resting pressure = 66 mmHg) (p < 0.001). The mean resting pressure in patients cured after 2 years was 75.65 mmHg, and in those with a recurrent fissure was 112.85 mmHg (p < 0.001).

Morbidity and recurrence were similar in open and closed sphincterotomies when the procedures were performed under local anesthetic, and sphincterotomy under local anesthesia as an outpatient procedure has several socioeconomic advantages (high degree of satisfaction and comfort to the patient, rapid solution of the problem, and no admission to the hospital or an operating room and no preoperative studies).