This comparative, multicentre, randomised clinical trial is designed with two parallel groups that will follow a treatment either with an autologous implant of ASCs (Adipose Derived Stem Cells) and fibrin glue (tissue adhesive material) or with fibrin glue alone for the non-surgical treatment of complex perianal fistula.

Comparative, multicentre, randomised clinical trial, designed with two parallel groups that will follow a treatment either with an autologous implant of ASCs (Adipose Derived Stem Cells) and fibrin glue (tissue adhesive material) or with fibrin glue alone for the NON-SURGICAL treatment of complex perianal fistula. The closure/healing of the fistula will be evaluated periodically, and it will be considered completely closed if there is no suppuration from the external orifice and re-epithelialisation can be observed at 8 weeks after the administration of the randomised therapy.

Inclusion Criteria:

• Patients of both sexes older than 18 years of age.

• Patients with a complex perianal fistula pathology which we define as the subjects that fulfil some of the following conditions:

  • No palpation of the fistula tract beneath the perianal skin.
  • A tract that is parallel to the rectum on exploration with a stylet.
  • Associated faecal incontinence.
  • Risk factors of anal incontinence.
  • At least one previous operation for a fistulous disorder.
  • Suprasphincteric trajectories
  • Rectovaginal fistula
  • Prior diagnosis of Crohn's disease.

• Patients from whom written informed consent has been obtained for them to participate in the study prior to performing any procedure described in the study.

• Patients that have already been subjected to a colonoscopy within a period of up to 6 months prior to the study.

Exclusion Criteria:

• Patients that are extremely thin who should not be subjected to liposuction.
• Known allergy to local anaesthetics or to bovine proteins
• History of neoplasia in the past 5 years.
• Patients with a diagnosis of active Tuberculosis at the moment of inclusion.
• Patients with prior positive markers for any of the following pathogens: Hepatitis B and C, HIV-1 or HIV-2.
• Any other medical condition that in the judgement of the investigator could interfere with their optimal participation in the study or produce a significant risk to the patient.
• Patients that have participated in another study in the 30 days prior to this one or that have planned to participate simultaneously in another study.
• Patients that have not given their informed consent to participate in this study.
• Psychiatric disorder or other factors that in the judgement of the investigator could complicate the participation of the patient in the study.
• Breast feeding, gestation or intention to become pregnant up to 6 months after finalising their participation in the study, or that are not using adequate methods of contraception during the same period.