Abstract: Objective To investigate the effect of trans-sphincter space drainage on postoperative pain, anal function, and anal fistula formation rate in patients with high intramuscular posterior horseshoe shaped perianal abscess. Methods A total of 90 patients with high intramuscular posterior horseshoe shaped perianal abscess were selected from January 2020 to July 2023, and randomly divided into a study group and a control group with 45 cases in each group. The patients in the control group were treated with incision and thread-drawing, while those in the study group were treated with drainage through sphincter space. The two groups were compared in terms of pain [visual analogue scale （VAS） score], anal function （Wexner score）, and anal fistula formation rate. Results After surgery, the VAS score of the study group was significantly lower than that of the control group （P<0.05）, the Wexner score was lower （P<0.05）, and the incidence rate of anal fistula was also lower （P<0.05）. Conclusion Trans-sphincter space drainage surgery can effectively alleviate postoperative pain, improve anal function, and reduce the incidence of postoperative anal fistula in patients with high intramuscular horseshoe shaped perianal abscess.

Key words: Trans-sphincter space drainage surgery, High intramuscular posterior horseshoe shaped perianal abscess, Anal function, Pain score