Pilot Study of rhBMP-2/BCP in Patients With Spinal Degeneration With Instability Requiring Surgical Fusion

Inclusion Criteria: * Subject has radiographically documented spinal degeneration with instability as documented by the presence of translation \>= 4mm or angulation \>= 5°. * Subject has intractable back pain which does not respond to conservative treatment and in the investigator's opinion, requires surgical spinal fusion. * Subject's pain is predominantly associated with the back. * Subject has only one level involvement at L3-L4, L4-L5, or L5-S1. * Subject is 18 years of age or greater at the time consent is given to participate in the study. * Subject is willing to comply with the study plan and sign the informed consent. * Subject is male or a non-pregnant, non-nursing female. All females of child-bearing age must agree to use adequate contraception for a period of no less than 16 weeks following surgery. Exclusion Criteria: * Subject has primary spinal diagnosis of a disorder other than spinal degeneration with instability at the involved surgical level. * Subject has spinal stenosis or condition which requires a full laminectomy procedure. * Subject has had a previous fusion, discectomy or laminectomy procedure at L3-L4, L4-L5 or L5-S1. * Subject has received drugs which may interfere with bone metabolism within two weeks prior to the planned date of spinal fusion surgery (e.g., steroids, methotrexate) or has a condition which requires postoperative medications that interfere with fusion (e.g., steroids, nonsteroidal antiinflammatory drugs, or methotrexate). * Subject has overt or active infection near the operative spinal region. * Subject has active systemic infection. * Subject has history of autoimmune disease (Systemic Lupus Erythematosus or Dermatomyositis). * Subject's history includes hypersensitivity to protein pharmaceuticals (monoclonal antibodies or gamma globulins). * Subject 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/BCP implantation. * The subject requires electrical bone growth stimulation, allograft, or bone substitute as part of treatment. * Subject has history of endocrine or metabolic disorder known to affect osteogenesis (e.g. Paget's disease, renal osteodystrophy, Ehlers Danlos syndrome, or osteogenesis imperfecta). * Subject has a known diagnosis of diabetes which requires treatment with medication. * Subject has received previous radiation therapy at the site to be fused. * Subject is unwilling to return for required follow-up visits. * Subject is a prisoner. * Subject has insufficient bone mass which precludes surgery (e.g., severe osteopenia or osteoporosis).