“…2 The classification of anal fistula was proposed by Parks et al, who assigned the fistulas into 1 of 4 groups: intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric. 2,[5][6][7] For the patients with chronic inflammatory disease of the gastrointestinal tract such as Crohn disease or with the repeated surgical treatments, 2 or more fistulas or internal openings, sometimes the iatrogenic internal openings caused by operations, may be detected, and the location of these lesions may be very deep. 2,[5][6][7] For the patients with chronic inflammatory disease of the gastrointestinal tract such as Crohn disease or with the repeated surgical treatments, 2 or more fistulas or internal openings, sometimes the iatrogenic internal openings caused by operations, may be detected, and the location of these lesions may be very deep.…”