Hi & Welcome. I appreciate your concern for your beloved father s problem. Since your father did not respond to Seitz baths (warm water wash) and other medicines, so he needs a surgical procedure under general anesthesia to remove the fistula. Since fistulas are know to recur if not excised properly a fistulogram (dye injected from the external opening to the inner opening to locate the tract should be done first. Then a fistulotomy the most commonly used type surgery is done under the general anesthesia. It involves cutting open the entire length of the fistula, from the internal opening to the external opening. The surgeon will flush out the contents and flatten it out. After one to two months, the fistula will heal into a flat scar. Regarding laser therapy, its efficacy in preventing the recurrence is not proven hence it is not done frequently. Hope this answers your query.