University of Kansas Medical Center

(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.

(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).