[Long-term efficacy of bioprosthetic anal fistula plug in the treatment of transsphincteric anal fistula].

To evaluate the long-term healing rate of transsphincteric anal fistula treated with anal fistula plug procedure and the risk factors affecting the healing of anal fistula. A retrospective case-control study was conducted to analyze the clinical data of 207 patients with transsphincteric anal fistulas who received anal fistula plug procedure at the Department of General Surgery, Beijing Chaoyang Hospital of Capital Medical University from August 2008 to September 2012. Inclusion criteria: (1) consistent with the diagnosis of transsphincteric anal fistula: the anal fistula passed through the internal and external sphincter; (2) complete data; (3) initial treatment with anal fistula plug procedure. Exclusion criteria: (1) acute rectal or perianal infection or poorly controlled focal infection; (2) recent incision and drainage of perianal abscess or spontaneous rupture of abscess; (3) patients with malignant tumor; (4) patients with Crohn's disease or ulcerative colitis; (5) patients with heart, liver, brain, lung or renal insufficiency; (6) cachexia due to various chronic wasting diseases; (7) patients could not tolerate surgery. Patients were followed up for anal fistula healing. The cumulative healing rate of patients with transsphincteric anal fistula was plotted using the Kaplan-Meier method, and the factors affecting anal fistula healing were explored by univariate and multivariate logistic regression analysis. There were 186 males and 21 females with age of 15 to 69 (mean 38) years. The duration of anal fistula was 3-60 (mean 15) months. Three patients had a history of previous episodes of perianal abscess and underwent incision and drainage of perianal abscess (all more than 3 months). During follow-up ending on October 31, 2018, 72 patients (34.8%) were lost to follow-up. Among 135 patients who were successfully followed up, the average follow-up period was 96 (75-124) months. Seventy-five patients had anal fistula healing, with healing rate of 55.6%. Kaplan-Meier survival curve showed that the healing time of anal fistula was prolonged and finally stabilized at 55.6%. In the patients who failed initial treatment with anal fistula plug packing, there were 6 cases whose anal fistula healed spontaneously without other treatment. Among them, 3 cases healed spontaneously 2 years and 3 cases 3 years after operation without recurrence. From 2008 to 2012, the annual healing rates of anal fistula plug treatment were 3/6, 61.5% (24/39), 42.1% (24/57), 12/15 and 12/18, respectively. Multivariate logistic regression analysis showed that the duration of anal fistula≥6 months (OR=3.187, 95% CI: 1.361-7.466, =0.008) was an independent risk factor for anal fistula healing after treatment with anal fistula plug. The long-term efficacy of anal fistula plug procedure in the treatment of transsphincteric anal fistula is positive, and this procedure should be implemented as soon as possible.