rhBMP-2/CRM/CD HORIZON® Spinal System Pivotal Study

Inclusion Criteria: Each patient participating in this clinical trial must meet all of the following inclusion criteria: 1. Has degenerative disc disease as noted by back pain of discogenic origin, with or without leg pain, with degeneration of the disc confirmed by patient history of pain and radiographic studies: 2. Requires fusion of a single level disc space from L1 to S1. 3. Has not responded to non-operative treatment (e.g., bed rest, physical therapy, medications, spinal injections, manipulation, and/or TENS) for a period of 6 months. 4. If of child-bearing potential, patient is non-pregnant, non-nursing, and agrees to use adequate contraception for 1 year following surgery. Exclusion Criteria: A patient meeting any of the following criteria is to be excluded from this clinical trial: 1. Has primary diagnosis of a spinal disorder other than degenerative disc disease with Grade 1 or less spondylolisthesis at the involved level. 2. Had previous spinal fusion surgical procedure at the involved level. 3. Requires spinal fusion at more than one lumbar level. 4. Has been previously diagnosed with osteopenia. 5. Has presence of active malignancy or prior history of malignancy (except for basal cell carcinoma of the skin). 6. Has a history of autoimmune disease (e.g. Systemic Lupus Erythematosus or dermatomyositis). 7. Has a history of exposure to injectable collagen or silicone implants. 8. Has received treatment with an investigational therapy within 28 days prior to implantation surgery or such treatment is planned during the 16 weeks following rhBMP 2/CRM implantation. 9. Has received any previous exposure to any/all BMP's of either human or animal extraction.