Fleet enema was used for preoperative bowel preparation in all cases. Operation was done under general anesthesia in the lithotomy position. Prophylactic antibiotics were used with ciprofloxacin 500 mg and metronidazole 500 mg preoperatively and twice daily for 5 days. Examination under anaesthesia (EUA) was firstly performed and the extent of the disease was established by cannulating the fistulas with probes and by laying open all primary tracts, extensions, and abscesses. All the incisions and dissections were made by electrocautery. The standard procedure was to perform core fistulectomy and traversing the external sphincter until the internal sphincter was exposed the track was then transected. The crypt-bearing tissue around the internal opening of the fistula is excised, if there is difficulty in excising the main tract, the granulation tissue of the remaining tract is scraped with a curette. Advancement flap was constructed in both group.