A phase II, comparative, open label, prospective, multicentre clinical trial where each patient will undergo two procedures; implant of a patch of cultured chimeric skin (experimental therapy) in a half of the skin lesion and an occlusive non-adherent dressing (control) in the other half for 12 months of follow-up in two Spanish centres.

Reconstruction of interdigital commisures in patients with severe skin syndactyly using laminar grafts that will be uniformly and systematically taken with an electrical or compressed air dermatome on an aseptic area and with the same extent and depth in microns in all patients.

Immediately after the surgical procedure, a patch of cultured chimeric skin (experimental therapy) will be implanted in a half of the skin defect of the patient, and an occlusive non - adherent dressing (control) will be implanted in the other half.

Patients will initially be followed up every two days until epithelisation occurs (approximately 21 days after surgery) and at 3,8,and 12 months of follow-up.

Inclusion criteria:

• Patients of both sexes over 28 days of age.
• Patients with recessive dystrophic epidermolysis bullosa diagnosed by clinical and historical criteria with severe skin syndactyly in whom reconstructive surgery is indicated.
• Patients whose legal guardians have given written informed consent for participation in the study before any study procedure is performed.
• Patients aged ≥ 12 years who have given written informed consent for participation in the study before any study procedure is performed.

Exclusion criteria:

• Women of childbearing age not using effective contraceptive methods (oral contraception)
• Pregnant or nursing women
• Documented or suspected hypersensitivity to any of the therapeutic agents included in the study, including anaesthetic drugs.
• Patients with a history of malignant tumor in the past 5 years
• Patients with a diagnosis of active tuberculosis at the time of recruitment
• Patients with prior positive markers for any of the following pathogens: hepatitis b and c, hiv-1 and hiv-2
• Patients with a history of clinically relevant hepatic, gastrointestinal, haematological, pulmonary, or neurological disease no directly related to epidermolysis bullosa.
• Any other medical condition which, in the investigator´s judgment, might interfere with optimal participation in the study or involve a significant risk for the patient.
• Alcoholism, drug addiction, psychiatric disorders, or other factors present in legal guardians which,in the investigator´s judgment may complicate patient participation in the study.