Fistura® Procedure for the Treatment of Complex Anal Fistulas

Radiofrequency Using the Fistura® Procedure for the Treatment of Complex Anal Fistulas: Assessing Healing Rate and Anal Incontinence up to 1 Year Follow-up

Study design was changed before study start/approval. Dr. Nebbot will no longer be sponsor. Study design will change to a commercial design and manufacturer of the device will be sponsor of the study.

This study aims to evaluate the healing rate of complex fistulas using radiofrequency (Fistura® procedure), in a prospective, interventional, monocenter, single-arm design.

Perianal fistula is a rare disease characterized by a tract that connects the perineal skin to the anal canal. These fistulas usually lead to anal pain, intermittent anal purulent discharge and abscess recurrence. The choice of the treatment depends on the type of fistula, simple or complex fistulas. Simple fistulas are defined as inter-sphincteric and trans-sphincteric fistulas involving less than 30 % of the external sphincter. Complex anal fistulas include trans-sphincteric fistulas involving more than 30% of the external sphincter, supra-sphincteric fistulas, extra-sphincteric fistulas, horseshoe fistulas or fistulas involving multiple tracts, anal fistulas associated with inflammatory bowl disease, radiation, malignancy, preexisting fecal incontinence or chronic diarrhea. While treatments in one stage (including fistulotomy (laying open the fistula tract) and fistulectomy (excision of the fistula tract) have shown an acceptable benefit (healing) / risk (incontinence) balance for the treatment of simple fistulas and have become the treatment of choice, there is a risk of incontinence in up to 80 % of patients with a complex fistula after one stage treatment. Alternative "sphincter-saving techniques" have been developed. However, none have shown evidence of superiority in terms of healing rate or anal incontinence. It therefore seems appropriate to develop new treatment alternatives for patients with a complex anal fistula. The clinical investigation is designed to evaluate the global healing rate of complex anal fistulas after radiofrequency procedure using the Fistura® procedure. Healing rate will be evaluated clinically and by performing an MRI. Secondary outcomes include healing rate per type of fistulas, assessment of anal incontinence, energy used and duration of the procedure, return to daily activities and work, quality of life and postoperative complications.

The Fistura® procedure is performed using a sterile Fistura® catheter (F Care Systems), intended to be connected to an F Care Systems radiofrequency generator (MedRF4000®) (both CE-marked). The flexible Fistura® catheters used during the procedure allow it to follow the path of the anal fistula, facilitating the closure of the fistula along its entire length. To allow closure, the tip of the catheter will heat the fistula and cause coagulation. The thermal effect around the catheter tip has a 3 mm radius, avoiding damage to surrounding tissue or muscle. The catheter is available in different sizes depending on the diameter of the anal fistula (6F, 7F, 8F, 9F). One Fistura® catheter will be used per patient, a total of 50 Fistura® catheters in this study. As the catheter can treat fistulas involving the sphincter complex, but without cutting or damaging it, it is expected to be effective in term of continence maintenance.

Types of fistulas include trans-sphincteric fistulas involving more than 30 % of the external sphincter, supra-sphincteric fistulas, extra-sphincteric fistulas, horseshoe fistulas or fistulas involving multiple tracts

Measured by the standard index of Jorge and Wexner. This score ranges from 0/20 for a perfect anal continence to 20/20 for a total incontinence. For scores above 10/20, the incontinence is considered severe.

Measured by the Quality of Life Anal Fistula Questionnaire (QOLAF-Q) score. Measures quality of life in people with anal fistula and its score range is the following: zero impact=14 points, limited impact=15 to 28 points, moderate impact=29 to 42 points, high impact=43 to 56 points, and very high impact=57 to 70 points.

Complications are defined as the number of adverse events related to the treatment and with abnormal MRI values

Inclusion Criteria: Patients with complex fistulas. Complex fistulas include trans-sphincteric fistulas involving more than 30 % of the external sphincter, supra-sphincteric fistulas, extra-sphincteric fistulas, horseshoe fistulas or fistulas involving multiple tracts (according to the ASCRS) for which: Suppuration is described by the patient and/or visible by an opening in the anal margin or by anoscopy Clinical symptoms led to an MRI demonstrating the path Fistula path demonstrated in the acute phase during drainage of an abscess Patient ≥ 18 years at study entry Patients with a previously drained fistula, without diverticula > 10 mm, without T2 hyperintensity (assessed by MRI). Drainage is achieved by placing a seton from 10 weeks to 12 months prior to the procedure. Patient and investigator signed and dated the informed consent form prior to the procedure Exclusion Criteria: Patient < 18 years at study entry Patient has a known contraindication to treatment using radiofrequency (infectious anal pathologies, anal fissures, residual Longo anterior treatment staples) Patient has a known contraindication to MRI Simple fistulas defined as inter-sphincteric or trans-sphincteric, involving less than 30 % of the total height of the sphincter apparatus (attested by MRI, ASCRS classification) Patient has a fistula associated with radiation and inflammatory bowel disease Patient is unable/unwilling to provide informed consent Patient is unable to comply with the protocol or proposed follow-up visits and questionnaires Patient is currently participating in another clinical study