Guideline sources The following summarized guidelines for the evaluation and management of anorectal fistula are prepared by our editorial team based on guidelines from the American Society of Colon and Rectal Surgeons (ASCRS 2022), the American College of Radiology (ACR 2021), the World Society of Emergency Surgery (WSES/AAST 2021), the American College of Gastroenterology (ACG 2018), and the Association of Coloproctologists in Germany (BCD/DGAV/DGAV/DDG/DGGG/DGU/DGK/AGUB/CACP 2017). 1 2 3 4 5 Guidelines 1. Diagnostic investigations Clinical examination: As per ASCRS 2022 guidelines, elicit a disease-specific history and perform a physical examination assessing symptoms, relevant history, location of the fistula and abscess, and the presence of secondary cellulitis in the initial evaluation of patients with anorectal fistula. B As per DGAV 2017 guidelines, elicit a medical history and perform a clinical examination to establish the indication for surgery in patients with anorectal fistula. A Diagnostic imaging: As per ASCRS 2022 guidelines: https://web.pathway.md/diseases/recjc0smgZlZ1OMzP 1/4 6/23/23, 2:37 AM p Anorectal fistula Pathway g Do not obtain routine diagnostic imaging in patients with anorectal fistula. D Consider obtaining imaging in selected patients with recurrent or complex anal fistula, immunosuppression, or anorectal Crohn's disease. B As per ACR 2021 guidelines, consider obtaining pelvic MRI without and with IV contrast or pelvic CT with IV contrast as the initial imaging in patients with suspected anorectal fistula. C As per DGAV 2017 guidelines, obtain further investigations (anorectal ultrasound, MRI) only in case of recurrent, complex abscesses and complex fistulas of difficult clinical classification. A 2. Therapeutic procedures Cutting seton placement: As per ASCRS 2022 guidelines, consider placing a cutting seton selectively in the management of complex cryptoglandular anal fistulas. C As per DGAV 2017 guidelines: Consider placing a cutting seton to prepare for subsequent definitive treatment of high anal fistulas demonstrated during abscess drainage. C Do not undertake special bowel preparation in case of seton placement. D Fistula plugging: As per ASCRS 2022 guidelines, consider placing an anal fistula plug for the management of patients with fistula-in-ano, recognizing that this method is relatively ineffective. B As per DGAV 2017 guidelines, consider performing fistula plugging for the management of patients with high anal fistula, recognizing that the healing rates are quite low. C Fibrin glue injection: As per ASCRS 2022 guidelines, consider injecting fibrin glue for the management of patients with fistula-in-ano, recognizing that this method is relatively ineffective. B As per DGAV 2017 guidelines, consider applying fibrin glue only in special cases. C Collagen injection: insufficient evidence to recommend collagen injection for the treatment of patients with anal fistula. I Autologous stem cell injection: insufficient evidence to recommend autologous stem cell injection for the treatment of patients with anal fistula. I 3. Perioperative care Postoperative care: advise rinsing anal area regularly, using tap water. Recognize that the use of local antiseptics is associated with a risk of cytotoxicity. Use antibiotics only in exceptional cases. B https://web.pathway.md/diseases/recjc0smgZlZ1OMzP 2/4 6/23/23, 2:37 AM Anorectal fistula Pathway 4. Surgical interventions Fistulotomy: As per ASCRS 2022 guidelines, consider performing lay-open fistulotomy in patients with simple fistula-in-ano and normal anal sphincter function. B As per DGAV 2017 guidelines, perform primary fistulotomy only in patients with superficial fistulas and by experienced surgeons. A Show 3 more Endoanal advancement flaps: as per ASCRS 2022 guidelines, consider performing endorectal advancement flap repair in patients with fistula-in-ano. B Ligation of intersphincteric fistula tract: As per ASCRS 2022 guidelines, consider performing ligation of the intersphincteric fistula tract for the treatment of patients with transsphincteric fistulas. B As per DGAV 2017 guidelines, consider performing ligation of intersphincteric fistula tract for the treatment of patients with complex fistulas. Recognize that healing and continence rates do not differ significantly from those of the flap procedures. B Fistulectomy with primary reconstruction: consider performing fistula excision with primary reconstruction of the sphincter muscle following complete excision of the fistula and its associated inflammatory tissue, primary readaptation of the divided sphincter apparatus in patients with anorectal fistula. B Show 2 more 5. Specific circumstances Patients with concomitant anorectal abscess: As per ASCRS 2022 guidelines, consider performing concomitant fistulotomy along with abscess drainage in selected patients with anorectal abscess and simple anal fistula. C As per WSES 2021 guidelines, consider performing fistulotomy at the time of abscess drainage in patients with anorectal abscess and an obvious fistula, only in cases of low fistula not involving sphincter muscle (subcutaneous fistula). C Show 2 more Patients with Crohn's disease: As per ASCRS 2022 guidelines, manage anorectal fistula associated with Crohn's disease with a combination of surgical and medical approaches. B Show 6 more As per ACG 2018 guidelines, perform abscess drainage (surgically or percutaneously) before initiating anti-TNF agents for fistulizing Crohn's disease. B Show 3 more https://web.pathway.md/diseases/recjc0smgZlZ1OMzP 3/4 6/23/23, 2:37 AM Anorectal fistula Pathway References 1. Andreas Ommer, Alexander Herold, Eugen Berg et al. German S3 guidelines: anal abscess and fistula (second revised version). Langenbecks Arch Surg. 2017 Mar;402 2 191 201. Open 2. Wolfgang B Gaertner, Pamela L Burgess, Jennifer S Davids et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2022 Aug 1;65 8 964 985. Open 3. Expert Panel on Gastrointestinal Imaging: Angela D. Levy, MD, Peter S. Liu et al. ACR Appropriateness Criteria Anorectal Disease. ACR. 2021. Open 4. Antonio Tarasconi, Gennaro Perrone, Justin Davies et al. Anorectal emergencies: WSES AAST guidelines. World J Emerg Surg. 2021 Sep 16;16 1 48. Open 5. Lichtenstein GR, Loftus EV, Isaacs KL et al. ACG Clinical Guideline: Management of Crohn's Disease in Adults. Am J Gastroenterol. 2018 Apr;113 4 481 517. Open 6. Vogel JD, Johnson EK, Morris AM et al. Clinical Practice Guideline for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2016 Dec;59 12 1117 1133. Open https://web.pathway.md/diseases/recjc0smgZlZ1OMzP 4/4