AIMS AND OBJECTIVEThe main aim of this study was to assess the relief of symptoms and the healing of the anal fissure using the two techniques of lateral internal sphincterotomy and controlled intermittent anal dilatation. MATERIALS AND METHODSThirty patients who were randomised into two groups underwent lateral internal sphincterotomy or controlled intermittent anal dilatation. Randomisation to treatment by either lateral internal sphincterotomy or controlled intermittent anal dilatation was done on the basis whether the patient's registration number was odd or even. A total of 16 patients were treated by lateral internal sphincterotomy and 14 patients by controlled intermittent anal dilatation. All cases were done under general anaesthesia. The improvement in patient's symptoms as well as healing of the fissure were recorded and the results were compared. No serious complications were observed in either group. Patients were followed up for six months post procedure. RESULTSNo differences were observed with respect to immediate relief of pain, bleeding, mucous discharge, healing of the anal fissure, surgical complications and time off work. The post-operative symptoms in the form of pain, bleeding and constipation did not differ significantly between the two groups and were easily controlled with analgesic, stool softeners and sitz baths. The patients were also asked to hydrate themselves well and advised to have a diet rich in vegetables and fruit. Two months post-operatively, 16 patients in the lateral sphincterotomy group and 14 patients in the controlled intermittent anal dilatation group had healed completely and had no anal incontinence or other serious complications. At 6 months follow-up however 2 patients in the anal dilatation group complained of impaired control of flatus and faeces, although there was no soiling of the underwear. At the same point in time, one patient in the sphincterotomy group and 3 patients in the anal dilatation group had a recurrence. No statistical difference however existed in either treatment groups as regards to the relief of symptoms, the healing of the fissure and anal incontinence. CONCLUSIONLateral internal sphincterotomy is one of the most favoured procedures. The reason for this is the simplicity of the procedure, the minimal anaesthesia requirements and excellent results. Controlled intermittent anal dilatation applied with a standardised technique reduced anal canal resting pressure, cured symptoms and provided symptomatic healing that was equivalent to that of a lateral internal sphincterotomy. Since there were no findings of incontinence or situations which resulted in anal sphincter damage, we conclude that controlled intermittent anal dilatation is suitable for patients with chronic anal fissures because of its less invasive nature as compared to lateral sphincterotomy with equivalent efficacy and safety. In addition, the controlled intermittent anal dilatation method may be an alternative procedure in older and multiparous women who has a higher risk o...