Inclusion Criteria:  Subject has been diagnosed with DDD (as defined below), degenerative spondylolisthesis or lumbar spinal stenosis at one spinal level:  DDD defined as one or more of the following: instability as defined by greater than or equal to 3 mm translation or greater than or equal to 5 degrees angulation, decreased disc height, on average by greater than or equal to 2 mm, but dependent upon the spinal level, scarring/thickening of ligamentum flavum or annulus fibrosis, herniated nucleus pulposus or vacuum phenomenon.  The subject has failed at least six months of non-operative treatment prior to clinical study enrolment (e.g. bed rest, physical therapy, bracing, traction, drug therapy, etc) and is a candidate for spinal fusion surgery over one vertebral level between, and including, L2 to S1 (i.e. second lumbar to first sacral). The subject is 40-65 years old. The subject is, in the Investigator's opinion, psychosocially healthy and physically able to fully comply with this protocol, including the post-operative regimen, required follow up visits, the filling out of required forms, and have the ability to understand and give written informed consent.  Exclusion Criteria:  Subject has diagnosis of symptomatic DDD, spondylolisthesis, or lumbar spinal stenosis at more than one level. Subject has had prior surgery at any lumbar level. Subject has systemic infection or infection at the surgical site. History of significant metabolic bone disease such as osteomalacia, autoimmune disease including rheumatoid arthritis, renal disease, hepatic disease, peripheral vascular disease, insulin dependent diabetes, Paget's disease at the involved spinal level(s) or upper motor neuron disease (positive Babinski sign). Subject has a medical condition that would interfere with post-operative assessments and care (i.e. psychiatric disease, paraplegia, quadriplegia, etc.). Subject is in poor general health or any concurrent disease process that would place the subject in excessive risk to surgery (e.g. significant circulatory, pulmonary problems, or cardiac disease). Subject has a history (present or past) of substance abuse (recreational drugs, prescription drugs or alcohol) that in the Investigator's opinion may interfere with protocol assessments and/or with the subject's ability to complete the protocol required follow up. The subject is known to be pregnant/breastfeeding at the time of enrolment or plans to become pregnant during their participation in the clinical study. Subject is participating in, or has completed within the last 30 days, another investigational clinical study, which could confound results. Morbid obesity defined as a Body Mass Index (BMI) ≥ 40. Has or has had a tumour or fracture at the involved level. Subject has a condition or requires post-operative medications that may interfere with bone/soft tissue healing (i.e. NSAIDS, oral or parenteral glucocorticoids, immunosuppressants, methotrexate, etc.), or that effect the rate of bone metabolism unless they have undergone a 14 day wash out period prior to surgery. Subject is taking medication for treatment of osteoporosis and/or in the Investigator's opinion, spinal instrumentation would be contraindicated. Subject has a T-score of less than -2.5 is therefore diagnostic of osteoporosis. Subject is involved in on-going litigation concerning their medical condition. Subject has a known allergy to silicon. Long-term use (longer than 3 months) of opiates.