This study deals with the feasibility of an ATMP (Advanced Therapy Medicinal Product) production for the treatment of chronic wounds ulcer. Recruitment concerns patients (n=7) with leg ulcers and receiving a skin pellet graft. During surgical procedure, supernumerary biopsies are planned to be done in order to be transferred to laboratory. Then, the possibility of cell extraction (keratinocytes and fibroblasts), expansion, banking and use for skin substitute production in clinical condition is evaluated (primary outcome).

Inclusion Criteria:

• Patient with chronic leg ulcers evolving for more than 6 months
• Patient to receive skin pellet transplant
• Chronic wound area between 10 and 30 cm²

Exclusion Criteria:

• Patient without health insurance,
• Pregnant womens,
• Smoking patient,
• Chronic wound area >30 cm²