Abstract:Objective To analyze the effect of ligation of intersphincteric fistula tract (LIFT) technique and incision and thread drawing of anal fistula in treatment of complex anal fistula and its influence on anal function. Methods A total of 92 patients with complex anal fistula and who treated in Beijing Anorectal Hospital from July 2017 to November 2018 were selected, and the patients were divided into study group and control group by random number table method, with 46 cases in each group. The study group used LIFT surgery, and the control group used traditional incision and thread hanging surgery. The perioperative related indexes, surgical effect (cure rate, complication rate and recurrence rate after operation for 6 months) and the influence on anal function (anal function were determined by the pelvic floor electromyography and anorectal pressure and the degree of anal incontinence were determined by the Wexner score) were compared between the two groups. Results Perioperative indexes: the bleeding volume, wound area, visual analogue scale (VAS) 7 d after surgery and wound healing time in the study group were significantly shorter than those in the control group (P < 0.05); there was no significant difference between the two groups in operating time (P > 0.05). Surgical effect: the incidence of surgical complications in the study group was significantly lower than that in the control group (P < 0.05). There was no significant difference in recurrence rate and cure rate between the two groups (P > 0.05). Anal function: three months after operation, the time limit of action potential, anal resting pressure and maximum systolic pressure in the study group were significantly higher than those in the control group (P < 0.05), and the Wexner score in the study group was significantly lower than that in the control group (P < 0.05). Conclusion LIFT surgery and incision and thread hanging surgery have both advantages and disadvantages in the treatment of complex anal fistula. The former has little trauma, few complications and little influence on anal function, while the latter has a good surgical effect, but the recurrence rate is still high after the resection of complex anal fistula, which should be selected according to the specific situation in clinical practice.