This randomized and placebo controlled study investigates the efficacy of injections with freshly harvested autologous adipose tissue in CD patients with complex perianal fistulas refractory to standard surgical and/or medical treatment. 140 CD patients will be included and randomized to either treatment with freshly harvested autologous adipose tissue or placebo (saline). Primary outcome measures are clinical healing 6 months after treatment evaluated by clinical examination and pelvic MRI.

Injection with freshly harvested autologous adipose tissue has been reported to be an efficient treatment of perianal fistulas in patients with Crohn´s Disease (CD). In a prospective observational study 57 % of 21 patients with complex fistulas refractory to combined surgical and/or medical treatment achieved complete clinical healing of the treated fistulas from one to three injections.

This randomized and placebo controlled study aims to confirm the efficacy of injections with freshly harvested autologous adipose tissue in CD patients with perianal fistulas. 140 CD patients with complex perianal fistulas refractory to standard surgical and/or medical treatment will be included and randomized to either treatment with freshly harvested autologous adipose tissue or placebo (saline). Clinical evaluation of the treatment efficacy will also be performed in a blinded manner.

Inclusion Criteria:

• Diagnosed with Crohn´s Disease
• Perianal fistula with out branching or cavities with one external and one internal opening, which due to the risk for development of incontinence is not suitable for lay-open procedure, meaning: 1) all anterior interspinchteric and low transpinchteric (involving<1/3 of spinchter) in women 2) high interspinchteric fistulas 3) high transspinchteric (>1/3 of sphincter), suprasphincteric and ekstrasphincteric fistulas 4) intersphincteric or low transsphincteric fistula in patients with fecal incontinence and/or fecal urge.
• no or minimal luminal disease activity by colonoscopy < 3 months before treatment defined by Simple Endoscopic Severity for Crohn´s Disease<3
• Prior optimal medical treatment for fistulas (immunmodulators, antibiotics and/or anti-TNF-alfa treatment) with out achieving fistula healing
• Treatment with seton for a minimum of 6 weeks
• Speaks and understand Danish

Exclusion Criteria:

• Pregnancy
• Changes in immunmodulator or anti-TNFalfa treatment < 12 weeks
• Anovaginal fistulas
• Rectal or anal stenosis
• Active proctitis
• Stoma
• Previous surgery for fistulas besides simpel drainage or seton
• Smoker
• Insulin-dependent diabetes, conditions inducing defective immunity, pelvic radiation
• pelvic MRI contraindicated