Proposal for a new classification of anorectal abscesses based on clinical characteristics and postoperative recurrence

Figure 1 The flowchart of study design.

Figure 2 Clinical characteristics of fistula-prone abscess. A: There is a hard nodule, a depression, even a defect at the dentate line; B: Sclerotic tissue between the pus cavity and the anal canal by a finger touch; C: Pus oozes out of the corresponding area when press the pus cavity (direction of the yellow arrow); D: Liquid overflows when instilling hydrogen peroxide + methylene blue into the pus cavity during the operation (direction of the yellow arrow); E: Abscess cavity leading to the anal canal, internal sphincter involvement or discontinuity (direction of the yellow arrow in the ultrasound imaging); F: Abscess cavity leading to the anal canal, internal sphincter involvement or discontinuity (direction of the yellow arrow in the magnetic resonance imaging).