This observational study aims at assessing the safety and efficacy profiles of mesenchymal stem cell, in different formats (SVF, autologous, allogenic), to treat complex perianal fistula according to the Spanish national Compassionate-use law .

Under controlled circumstances, and approved by European and Spanish laws, a Compassionate-use Program allows the use of stem-cell therapy for patients with non-healing diseases, mostly complex fistula-in-ano, who do not meet criteria to be included in a clinical trial. Candidates had previously undergone multiple surgical interventions that had failed. The intervention consisted of surgery (with closure of the internal opening or a surgical flap performance), followed by stem cells injection. Three types of cells were used for implant: stromal vascular fraction, autologous expanded adipose-derived or allogenic adipose derived stem cells.

Healing was evaluated at 6th month follow-up. Outcome was classified as partial response or healing. Relapse was evaluated 1 year later. Maximum follow up period was 48 months.

Inclusion Criteria:

• patients with complex perianal fistula
• patients who didn't meet criteria of the clinical trial (CT) in development
• foreign patients, who were not allowed to be included in the CT
• patients included in some CT control arms
• failure treatment in patients included in a CT treatment arm as a retreatment

Exclusion Criteria:

• not signature informed consent

We present an observational study, including 52 cases (53% male and 47% female) treated by a compassionate use ASC program. The mean age was 45 years and ranged from 24 to 69 years. There were 42 perianal fistulas, 7 rectovaginal fistulas, 1 urethrorectal fistula, 1 sacral fistula and 1 hidradenitis suppurativa. All the cases had previous failed surgeries. Thirteen of fifty-two (25%) of the cases presented fecal incontinence at the moment of enrollment. 5/52 (9,6%) of the cases presented anal stenosis and 11/52 (21%) had a scaring anus.