Safety Study of Mesenchymal Stem Cells and Spinal Fusion

Inclusion Criteria: * L4-L5 degenerative spondylolisthesis grade I-II Meyerding isolated or associated to more than one level, and/or L4-L5 degenerative discopathy isolated or associated to more than one level. * 18 to 85 years of age (male and female) * Informed Consent Form signed * The patient is able to understand the nature of the study Exclusion Criteria: * Previous spine surgery * L4 isthmic spondylolisthesis * Smoker (more than 10 cigarettes a day) * Systemic or local infection * Patients treated with steroids (oral or systemic) within 3 months of entering the study, or treated with biphosphonates for more than 10 years * Positive serology for HIV-1 or HIV-2, Hepatitis B (HBsAg), Hepatitis C (Anti-HCV-Ab) or Syphilis. * Pregnant woman or intended to become pregnant, or breath feeding * Neoplasia within the previous 5 years, or without remission * Immunosuppressive states (except diabetes mellitus. Treatment with therapies is allowed) * Significant abnormal laboratory tests that contraindicates the surgery. * Participation in another clinical trial or treated with an investigational medicinal product the previous 3 months * Other pathologic conditions or circumstances that difficult participation in the study according to medical criteria * The patient does not accept to be followed-up for a period that could exceed the clinical trial length * The patient is legally dependent