Patients will be stimulated for 3 consecutive days with subcutaneous granulocyte colony stimulating factor (G-CSF) and then their bone marrow will be harvested according to their weight. Bone marrow will be processed in order to obtain the buffy coat and minimize the amount of red blood cells. An inoculum of 10mL of this TNC will be infused intrathecally. Patients will be evaluated with the "Gross Motor Functional Classification System" before the procedure and one, three and six months after that.