Safety Study for An Artificial Disc Nucleus Replacement to Treat Chronic Low Back Pain

Inclusion Criteria: * Patient is skeletally mature and between 22 and 60 years of age. * Patient has degenerative disc disease (DDD) at a single level between L1 and S1 as confirmed by:History and clinical findings suggestive of symptomatic DDD, Darkened disc on MRI in T2 weighted images, and decreased disc height (decreased greater than 2 mm compared to adjacent cranial or caudal disc height) with minimum disc height of 6 mm. * Patient has pre-operative back pain VAS score of greater than or equal to 4 (0-10 scale). * Patient has pre-operative Oswestry Low Back Disability score of greater than or equal to 40 (0-100 scale). * Patient has received conservative (non-surgical) treatment for back pain for a minimum of 6 months. * Patient has signed the approved Informed Consent Form. Exclusion Criteria: * Patient has had prior lumbar spine surgery. * Patient has motion of less than 3 degrees on pre-operative lateral flexion/extension radiographs. * Patient has ankylosing spondylitis or other spondyloarthropathy. * Patient has isthmic spondylolisthesis or degenerative spondylolisthesis greater than 2 mm. * Patient has congenital stenosis or epidural lipomatosis. * Patient has significant facet disease. * Patient has any known active malignancy. * Patient has previously undergone immunosuppressive therapy. * Patient has active local or system infection. * Patient has been diagnosed with hepatitis, rheumatoid arthritis, lupus erythematosus, or other autoimmune disease, including AIDS, ARC and HIV * Patient has diabetes mellitus (Type 1 or 2), requiring daily insulin management. * Patient has osteopenia of the spine (T-score less than 1.0). All females 45 years of age or older and all males 50 or older should have a DEXA scan to confirm this exclusion. * Patient has morbid obesity defined as body mass index (BMI) more than 40 or a weight of more than 45 kg (100 lbs) over ideal body weight. * Patient is pregnant or plans to become pregnant during the course of the study. * Patient has a known allergy to silicone (polymer and balloon material) or barium sulfate (polymer). * Patient participated in another investigational drug or device study within the past 30 days. * Patient belongs to a vulnerable population or has a condition such that his/her ability to provide informed consent, comply with follow-up requirements, or provide self assessments is compromised (e.g. developmentally disables, prisoner, chronic alcohol/ substance abuser) * Patient has a disc herniation * Patient has a Schmorl's node in the level to be treated Intraoperative exclusion criteria: * Protrusion of the 20A imaging balloon up to or beyond the outer margin of the vertebra during the imaging steps. * Patient has a violated endplate. * Patient has a disc space that is too narrow.