Regenn® Therapy System Safety Study

Inclusion Criteria (must meet ALL): * Subject has provided written informed consent on a form reviewed and approved by the Institutional Review Board for the clinical site. * The subject is 18 - 80 years old. * The subject has Spondylolisthesis of Meyerding Grade II or less, or has Degenerative Disc Disease (DDD) accompanied by back pain with or without leg pain at a level between L1 and S1 confirmed by history and radiographic assessment. DDD is determined to be present if one or more of the following are noted: * Instability (defined as angulation ≥ 5 degrees and/or translation ≥ 3mm on flexion/extension radiographs; * Osteophyte formation of facet joints or vertebral endplates; * Decreased disc height, on average by \>2mm, but dependent upon the spinal level; * Scarring / thickening of ligamentum flavum, annulus fibrosis, or facet joint capsule; * Herniated nucleus pulposus; * Facet joint degeneration / changes; and/or * Vacuum phenomenon. * Female subjects of childbearing potential must not be pregnant or nursing and must agree to use of contraception for the study duration. Female subjects who are surgically sterile or post-menopausal are exempt from having a pregnancy test and birth control. * The subject is willing and able to comply with the protocol mandated follow-up visits and testing regimen. Exclusion Criteria (candidates meeting ANY of the following at the time of the study procedure are NOT eligible): * Subject is unable or unwilling to provide informed consent or is unable to conform to the study protocol follow-up procedures and visits. * Subject has a contraindication (including allergic reaction) to antiplatelet/anticoagulant medications, nickel, titanium, bone allograft, or blood transfusion that is not amenable to pretreatment with steroids or/and antihistamines. * Subject has a history of bleeding diatheses or coagulopathy. * Subject has concomitant hepatic insufficiency, thrombophlebitis, uremia, systemic lupus erythematosus (SLE), or any autoimmune diseases. * Subject is receiving dialysis or immunosuppressive therapy. * Subject suffered a hemorrhagic stroke \< 6 months prior to the study procedure. * Subject is undergoing spinal surgery for vertebral fracture, trauma, or scoliosis. * Subject has any form of active malignancy. * Subject is an intravenous drug user and/or alcoholic. * Subject is diagnosed with septicemia at the time of the study procedure. * Subject is a smoker. * Subject has Type I diabetes. * Subject has overt, uncontrolled Type II diabetes. * Subject has a condition requiring postoperative medications that would be expected to interfere with fusion (e.g., steroids), or has received drugs that interfere with bone metabolism within 2 weeks of the surgery. * Subject is suffering from gross obesity, defined as \> 40% IBW. * Subject exhibits Waddell signs of Inorganic Behavior ≥ 3. * Subject has had a previous, anterior spinal fusion, interbody spinal fusion, or posterior spinal instrumentation at the involved level. * Subject has another medical condition, which may cause them to be non-compliant with the protocol, confound the data interpretation, or is associated with limited life expectancy of less than two years. * Subject has a systemic disease of connective tissue such as Rheumatoid Arthritis, or Ankylosing Spondylitis. * Subject is a prisoner. * Subject is currently participating in an investigational drug or another device study that has not completed the primary endpoint or that clinically interferes with the study endpoints. (Note: Trials requiring extended follow-up for products that were investigational, but have since become commercially available, are not considered investigational trials).