Comparative Analysis of Virtuos and Autograft in Lumbar Fusion

Inclusion Criteria: * Inclusion criteria: 1. At least 18 years of age at the time of surgery 2. Undergoing lumbar spine fusion surgery with one of the following bone grafting options: 1. Virtuos 2. Virtuos with Autograft (local bone) 3. Autograft 4. Autograft + allograft (cancellous bone chips) 3. Subject must have a documented diagnosis of DDD. DDD is defined by back and/or radicular pain with degeneration of the disc as confirmed by medical history, physical examination, and radiographic studies that may include CT, MRI, plain X-ray film, discography, myelography, etc. with one or more of the following findings: 1. Instability as defined by \>3mm translation or \>5 degrees angulation 2. Osteophyte formation of facet joints or vertebral endplates 3. Decreased disc height, on average by \>2mm, but dependent upon the spinal level 4. Scarring/thickening of ligamentum flavum, annulus fibrosis, or facet joint capsule 5. Herniated nucleus pulposus 6. Facet joint degeneration/changes; and/or 7. Vacuum phenomenon 4. Subject may have up to a Grade I Spondylolisthesis of the lumbar spine with clinical manifestations of one or more of the following phenomena: 1. Radiculopathy 2. Sensory deficit 3. Motor weakness 4. Reflex changes 5. Subject must require lumbar posterolateral arthrodesis at 1-2 contiguous levels (L1-S1). 6. The number of levels decompressed must equal the number of levels fused. 7. Subject must have been unresponsive to conservative care for at least 6 months prior to fusion surgery. 8. Subject must agree not to use electromagnetic adjuncts to enhance bone fusion during the course of the study 9. Subject must be willing and able to sign an informed consent document. 10. Subject must be willing and able to return for all follow-up visits, agree to participate in postoperative clinical and radiographic evaluations and comply with the required study regimen. Exclusion Criteria: Exclusion criteria: 1. Subject is under 18 years of age (\<18) at the time of consent 2. Subject has had prior lumbar spine fusion surgery at any level 3. Subject has greater than grade 1 spondylolisthesis of the lumbar spine 4. Subject is currently undergoing treatment for malignancy or has undergone treatment for malignancy in the past 5 years (benign skin cancer is permitted) 5. Subject is pregnant (confirmed by pregnancy test) or nursing or planning to become pregnant during the two years (24 months) following arthrodesis 6. Subject has an active local or systemic infection or is undergoing adjunctive treatment for local or systemic infection