Abstract: Objective To explore the therapeutic efficacy of the modified separation of external anal sphincter and the external anal sphincter bareness in treating high-level horseshoe shaped anal fistula.Methods 152 patients with high-level horseshoe shaped anal fistula admitted to the hospital from February 2021 to March 2024 were selected and categorized into two groups based on the type of surgical method:an observation group with 82 cases and a control group consisting of 70 cases.The observation group received treatment the modified separation of external anal sphincter,while the control group received treatment the external anal sphincter bareness.Compare the clinical efficacy,pain,anal function,anal pressure,postoperative complications,and recurrence rate between the two groups.Results The intraoperative blood output of the observation group was lower than that of the control group (P<0.05).At 7 and 14 days after surgery,the pain level scores of the two groups gradually decreased,and there was no statistically significant difference between the groups (P>0.05).At 1 month and 3 months after surgery,the Wexner anal incontinence score of the observation group patients was lower than that of the control group (P<0.05).Three months after surgery,the resting pressure,maximum systolic pressure,and maximum tolerance of the anal canal decreased in both groups,with the observation group being higher than the control group (P<0.05).Both groups of patients did not experience postoperative complications such as bleeding or infection.Six months after surgery,the recurrence rate in the observation group was higher than that in the control group (P<0.05).Conclusion The modified separation of external anal sphincter treatment for high-level horseshoe shaped anal fistula can reduce the incidence of postoperative anal incontinence in patients,but the postoperative recurrence rate is higher compared to the external anal sphincter bareness.

Key words: the modified separation of external anal sphincter；the external anal sphincter bareness；high position horseshoe shaped anal fistula, anal incontinence, anal pressure