SPIRA™-A 3D and HCT/p DBM vs. Medtronic Divergent™-L/Perimeter™ and Recombinant BMP-2

Inclusion Criteria: * skeletally mature adults * completed 6 month non-operative or conservative therapy * signed informed consent * back pain with radicular symptoms as evidenced by leg pain * Degenerative Disc Disease involving a single level between L2 and S1 * subject willing to participate in study and follow protocol * subject willing to comply with Post-op management program Exclusion Criteria: * systemic infection such as AIDS, HIV or Active hepatitis * autoimmune disease * significant metabolic disease that might compromise bone growth * history of malignancy * previous surgery for primary tumor, trauma or infection * subject requires 2 or more levels of fusion * previous spinal instrumentation or previous interbody fusion at involved level * spondylolisthesis of grade greater than/equal to 2