Inclusion Criteria:

- male or female 18 years or older,

- women of childbearing age who use an effective contraception method or women
incapable of becoming pregnant [(i.e. postmenopausal women for 1 year or surgically
sterile (hysterectomy and/or bilateral oophorectomy)],

- Patient with fistulizing anoperineal Crohn's disease. Anoperineal fistulas can be
associated with ileal, colic or rectal lesions,

- Patient with at least 1 anoperineal fistula drained with a seton for more than 1
month,

- Patient treated with adalimumab for more than 1 month,

- Patient who agrees to undergo surgery for its drained fistula(s),

- Patient with immunosuppressive therapy (azathioprine, 6-mercaptopurine ou
methotrexate) stable for at least 3 months or patients without immunosuppressive
therapy,

- Patient who gave signed written informed consent after having received verbal
explanation and written information related to the trial.

Exclusion Criteria:

- Pregnant or breastfeeding women,

- Patient having a perineal abscess,

- Patient with a high anovaginal fistula that cannot be treated, according to the
investigator ,with fistulotomy, gluing, biodegradable plug or advancement flap,

- Patient treated with a daily dose of corticosteroids of more than 20 mg (a dose of
more than 20 mg daily will be authorized during the study),

- Contraindication to proctological surgery on the drained fistula(s),

- Patient presenting with somatic or psychic signs or symptoms that are not compatible
with his/her participation in the trial according to the investigator,

- Patient who participate in another clinical trial.