Table 2.

Merits and demerits of fistulectomy vs transanal opening of the intersphincteric space vs modified transanal opening of the intersphincteric space

	Fistulectomy	TROPIS	Modified TROPIS
Surgical procedure	Remove the fistula, and surrounding muscles, fat and connective tissues	Identify the internal opening. Lay open the fistula tract in the intersphincteric plane through the transanal route. Resect the lower part of the internal sphincter. Scrap out the remaining branching fistulas	Widen the intersphincteric plane through the transanal route Identify the internal opening. A thorough drainage of fistulas passing through the intersphincteric plane. Tunnel-like fistulectomy of fistulas lateral to the external sphincter
Merits	Definite efficacy	High cure rate; small wound area; fast recovery	Easy to identify the internal opening and favor to the drainage and surgical procedure. Low risks of postoperative anal dysfunction and recurrence. Small wound area. Less pain. Fast recovery
Demerits	Large wound area; intensive pain; long recovery	Unable to clearly expose the surgical field. Not suitable for anal fistulas without a clearly identified internal opening. Not suitable for Asian people. High risks of bleeding and postoperative recurrence	Less popular. Lack of long-term follow-up data. Lack of a comparative group

TROPIS: Transanal opening of intersphincteric space.