Table 4. The Garg P. original classification system for anal fistulas.

FPR: fistulotomy with primary reconstruction, EAS: external anal sphincter, AFP: anal fistula plug.

Grade	Treatment guidelines
I: I-A: low-linear intersphincteric; I-B: low-linear transsphincteric (less than 1/3 of EAS involvement).	Fistulotomy should be possible in >95% of these AF.
II: low intersphincteric and transsphincteric AF (less than 1/3 of EAS involvement); II-A: abscess; II-B׃ multiple tracts; II-C׃ horseshoe; II-D׃ supralevator: complete intersphincteric supralevator AF; II-E: supralevator: Low transsphincteric (<1/3 EAS involvement) with intersphincteric supralevator extension.	Fistulotomy should be possible >90% of these AF.
III: III-A: high linear transsphincteric fistula (>1/3 EAS involvement); III-B: fistula with associated Crohn’s disease, sphincter injury, post-radiation exposure or anterior fistulae in a female.	Fistulotomy should not be attempted. FPR or sphincter-saving procedures: LIFT, VAAFT, AFP, TROPIS, OTSC, or FiLac therapy should be done.
IV: complex high (>1/3 EAS involvement). Transsphincteric fistula with either: IV-A: abscess; IV-B: multiple tracts; IV-C: Horseshoe.	Fistulotomy should not be attempted. FPR or sphincter-saving procedures: LIFT, VAAFT, AFP, TROPIS, OTSC, or FiLac therapy should be done. Preferably refer these AF to a fistula expert.
V: V-A: transsphincteric (>1/3 EAS Involvement) with intersphincteric supralevator extension; V-B: suprasphincteric fistula; V-C: extrasphincteric fistula.	Fistulotomy should not be attempted. FPR or sphincter-saving procedures: LIFT, VAAFT, AFP, TROPIS, OTSC, or FiLac therapy should be done. Preferably refer these AF to a fistula expert.