Hi. Thanks for your query. Noted the history and understood your concerns. Fistula always needs a surgery whether for the first time or for the recurrence but depends upon the type of fistula-in-ano. This can be diagnosed by the following ways: Per-rectal digital examination and ano-proctoscopy. Colonoscopy should be done in all the cases. Conventional fistulogram with contrast. MRI Fistulogram. Biopsy of the tract as you have has this for the second time. There is nothing like a specific laser treatment for such things. For low lying fistula a conventional fistulectomy is the best choice. For high anal fistula the operation can be done in stages or by suton treatment and other forms depending upon the exposure and experience of your treating General Surgeon or a Proctologist.