Risk factors for postoperative recurrence of anal fistula identified by an international, evidence-based Delphi consultation survey of surgical specialists.

Background: Despite the emerging knowledge about postoperative anal fistula recurrence (AFR) and the increasing number of clinical studies, there is no better understanding or consensus regarding the risk factors for AFR. The aim of this study was to generate international consensus guidance statements focusing on AFR.

Methods: A two-round modified Delphi process was conducted among international surgical specialists via an online survey delivered by email with a secure link created with Google Forms. Surgeons were asked to use a 9-point Likert scale to rate the importance of patient-, fistula-, and surgery-related statements developed based on our previous systematic review. Consensus was reached when at least 70% of panel members rated a statement as being of critical importance (ratings of 7-9).

Results: Of a total of 60 experts invited, 38 experts representing 13 countries from four continents agreed to participate in the first round of the Delphi process and 31 in the second round. In total, consensus was reached on 14 statements on the risk factors for AFR in three domains: patient-related risk factors included comorbid colitis, inflammatory bowel disease and use of immunosuppressants; fistula-related factors included transsphincteric fistula, number of fistula, horseshoe extension, undetected internal opening, location of anal fistula, recurrent fistula, suprasphincteric fistula, and height of the internal opening; and surgery-related factors included type of surgery, previous fistula surgery and surgeon.

Conclusion: This Delphi study provides an evidence-based profile of risk factors for AFR in the patient-, surgery- and fistula-related domains from a global perspective. Clinically, these indicators can be incorporated to develop risk calculation tools for the early detection of AFR in high-risk patients, allowing early prevention and intervention.