Anal fistula treatment is associated with increasing risk of anal incontinence until 40% of cases. New and alternative treatments (glue, advancement flap, plug…) decrease this risk, but with fistula efficacy treatment in 40 to 60% of cases. Radiofrequency might destroy fistula tract without lesion of anal sphincter.

Objective : Fistula healing rate and anal continence, 6 and 12 months after radiofrequency procedure.

Methods : Clinical and MRI evaluation before, 6 and 12 months after treatment. Patients : 50 patients with low, high, complex and Crohn disease fistula. An intermediate analysis is expected after the first 20 patients, to verify morbidity.

Evaluations :

• Fistula clinical healing 6 and 12 months after procedure
• Fistula MRI healing 12 months after procedure
• Anal continence before and after procedure
• Feasibility og radiofrequency procedure
• Morbidity
• Success and failure prognostics factors of this procedure

: Anal fistula treatment is associated with increasing risk of anal incontinence until 40% of cases. New and alternative treatments (glue, advancement flap, plug…) decrease this risk, but with fistula efficacy treatment in 40 to 60% of cases. Radiofrequency might destroy fistula tract without lesion of anal sphincter.

Objective : Fistula healing rate and anal continence, 6 and 12 months after radiofrequency procedure.

Methods : Clinical and MRI evaluation before, 6 and 12 months after treatment. Patients : 50 patients with low, high, complex and Crohn disease fistula. An intermediate analysis is expected after the first 20 patients, to verify morbidity.

Evaluations :

• Fistula clinical healing 6 and 12 months after procedure
• Fistula MRI healing 12 months after procedure
• Anal continence before and after procedure
• Feasibility og radiofrequency procedure
• Morbidity
• Success and failure prognostics factors of this procedure

Schedule :

• First inclusion march 2017
• Last inclusion march 2018
• Evaluations until march 2019.

Inclusion Criteria:

• Adult Patient agreeing to participate in the study and signing the consent to participate
• Patients with an anal fistula previously drained, without diverticulum> 10 mm in MRI after drainage.
• For women of childbearing age, they must have a negative urine pregnancy test

Exclusion Criteria:

• Patient minor,
• Patients who are linguistically or psychologically unable to understand the information given and to give informed consent,
• Patient incapable, in the opinion of the investigator, to complete the self-questionnaires,
• Against-indication to radiofrequency treatment (infectious anal pathologies, anal fissures, residual staples of previous treatment Longo,
• Pregnant woman,
• Patient carrying a pacemaker,
• Patients participating in another clinical study,
• Against indication to the realization of an MRI,
• Patient with a fistula with insufficient drainage, against indicating the removal of the stem (congestive fistula, oozing, with internal and / or external congestive orifices).