An MR imaging based classification was proposed to augment the surgical classification offered by Park primarily to facilitate radiologists to provide accurate detailed descriptive reports that will influence the management of these fistulas.
- Grade 1: simple linear intersphincteric fistula
- Grade 2: intersphincteric fistula with an abscess or secondary track
- Grade 3: transsphincteric fistula
- Grade 4: transsphincteric fistula with an abscess or secondary track in the ischiorectal or ischioanal fossa
- Grade 5: supralevator and translevator disease
- Parks, A. G., P. H. Gordon, and J. D. Hardcastle. “A classification of fistula‐in‐ano.” British Journal of Surgery 63.1 (1976): 1-12.
- de Miguel Criado, Jaime, et al. “MR imaging evaluation of perianal fistulas: spectrum of imaging features.”Radiographics 32.1 (2011): 175-194.
- Morris, John, John A. Spencer, and N. Simon Ambrose. “MR imaging classification of perianal fistulas and its implications for patient management 1.” Radiographics 20.3 (2000): 623-635.