For clinicians

Provider Resources

Pcrohns.org is written for patients. This page is the clinician-facing companion — a concise, evidence-anchored primer on perianal Crohn's disease for trainees and non-specialist providers. Every reference below has been verified against PubMed and links to its record. For the broader surgical evidence base, see Crohnsology.org; for luminal/intestinal disease, see Crohnz.org.

Fistula anatomy & classification

The Parks classification remains the anatomical framework for fistula-in-ano; management of perianal Crohn's is organised around fistula course relative to the sphincter complex.

  1. Parks AG, Gordon PH, Hardcastle JD. A classification of fistula-in-ano. Br J Surg. 1976;63(1):1-12. PMID 1267867
  2. Sandborn WJ, Fazio VW, Feagan BG, Hanauer SB. AGA technical review on perianal Crohn's disease. Gastroenterology. 2003;125(5):1508-30. PMID 14598268

Diagnosis & disease mapping

Accurate assessment combines pelvic MRI with examination under anaesthesia; MRI also tracks fistula response to therapy over time.

  1. Schwartz DA, Wiersema MJ, Dudiak KM, et al. A comparison of endoscopic ultrasound, magnetic resonance imaging, and exam under anesthesia for evaluation of Crohn's perianal fistulas. Gastroenterology. 2001;121(5):1064-72. PMID 11677197
  2. Van Assche G, Vanbeckevoort D, Bielen D, et al. Magnetic resonance imaging of the effects of infliximab on perianal fistulizing Crohn's disease. Am J Gastroenterol. 2003;98(2):332-9. PMID 12591051

Combined medical & surgical therapy

The evidence base favours a combined approach — seton drainage plus anti-TNF maintenance — over either alone for fistulising disease.

  1. Sands BE, Anderson FH, Bernstein CN, et al. Infliximab maintenance therapy for fistulizing Crohn's disease (ACCENT II). N Engl J Med. 2004;350(9):876-85. PMID 14985485

Mesenchymal stem-cell therapy

Local injection of expanded allogeneic adipose-derived mesenchymal stem cells (darvadstrocel) achieves durable healing of complex fistulas refractory to conventional therapy.

  1. Panés J, García-Olmo D, Van Assche G, et al. Expanded allogeneic adipose-derived mesenchymal stem cells (Cx601) for complex perianal fistulas in Crohn's disease: a phase 3 randomised, double-blind controlled trial (ADMIRE-CD). Lancet. 2016;388(10051):1281-90. PMID 27477896
  2. Panés J, García-Olmo D, Van Assche G, et al. Long-term efficacy and safety of stem cell therapy (Cx601) for complex perianal fistulas in patients with Crohn's disease. Gastroenterology. 2018;154(5):1334-42. PMID 29277560

Sphincter-sparing options (LIFT, advancement flap) and diversion/proctectomy for refractory disease follow society (ECCO/ASCRS) guidance and are individualised; see Crohnsology.org. This digest is educational and does not replace clinical judgement.