Inclusion criteria:

• Patient not currently participating in a drug or medical clinical trial.
• Patient signed informed consent.
• Patient is willing to be available for each examination scheduled over the study duration.
• Patient has clinical and radiologic history of degenerative disc disease or spondylolisthesis (no greater than grade 1 utilizing Meyerding's classification (Meyerding HW, 1932)); spinal stenosis for which conservative treatment has failed and lumbar spinal fusion is indicated.
• Eligible for non-instrumented or instrumented surgical procedure
• Has one or two levels (contiguous) involvement from L1-S1 requiring fusion
• Has preoperative Oswestry score greater than 30
• Has not responded to non-operative treatment for a period of 6 months (bed rest, physical therapy, medication, manipulations, spinal injections, other).
• Is at least 20 years of age inclusive at the day of surgery
• If female of childbearing potential, patient is non-pregnant, non-nursing, and agrees to use adequate contraception for one year following surgery.

Exclusion Criteria:

• Patient has a systemic infection.
• Patient has had more than one previous non-fusion spinal surgery at the involved level.
• Patient requires fusion at more than 2 levels.
• Patient has pseudoarthroses from a previous fusion attempt.
• Patient has highly communicable diseases, inflammatory or autoimmune disease (e.g.osteomyelitis, crohn's, rheumatoid arthritis, systemic lupus, gout, HIV/AIDS, active tuberculosis, venereal disease, active hepatitis). A note to file written by the investigator will permit a patient into the study who experiences a mild case which will not affect the outcome of the study.
• Has been previously diagnosed with osteopenia, osteoporosis, or osteomalacia to a degree that spinal instrumentation would be contraindicated
• Patient has a significant medical history that, in the Investigator's opinion would not make them a good study candidate.
• Patient requires interbody cage fusion or non-pedicle screw instrumentation.
• Pregnancy.
• Has presence of active malignancy (except basal cell carcinoma of the skin)
• Has a history of severe allergy (anaphylaxis)
• Is grossly obese, i.e. weight over 40% over ideal for their height and age.
• Has a fever (temperature over 101 F oral)
• Has an allergy to the BMP-2
• Has allergy to bovine products
• Has an allergy to collagen implants
• Is mentally incompetent(if questionable, obtain psychiatric consult)
• Is a prisoner, a transient or have been treated in an inpatient substance abuse program for alcohol and/or drug abuse within six months prior to proposed study enrollment.
• Has received drugs which may interfere with bone metabolism within two weeks prior to the planned surgery
• Has a diagnosis, which requires postoperative medication that interferes with fusion, such as steroids.
• Has history of endocrine or metabolic disorder known to affect osteogenesis (e.g. Paget's disease, renal osteodystrophy, Ehlers-Danios syndrome or osteogenesis imperfecta)