<prompt> Best treatment of refractory peri-anal fistula in crohns disease:-FistulectomyInfliximabOlasalizineMesalamine  <response>: Infliximab is effective in CD patients with refractory perianal and enterocutaneous fistulas, with 68 response rate 50 reduction in fistula drainage and a 50 complete remission rate. Reinfusion, typically every 8 weeks, is necessary to continue therapeutic benefits in many patients. 