Actifuse ABX Versus INFUSE in Posterolateral Instrumented Lumbar Fusion (PLIF) With Interbody Fusion

Inclusion Criteria: * Has degenerative disc disease of the lumbar spine as indicated by back pain of discogenic/degenerative origin, with or without leg pain, and has one or more of the following conditions as documented by plain X-rays, CT scan or MRI scan: * Modic changes. * High intensity changes in the annulus. * Loss of disc height. * Decreased hydration of the disc. * Canal stenosis with or without spondylotic slip. * Gross facet joint changes requiring fusion for treatment. * Have documented annular pathology by other means. (e.g., with discography). * Has a preoperative Oswestry Back Disability Score of 30 or more. * Aged 18 to 75 years and skeletally mature at time of surgery. * Has not responded to non-operative treatment (e.g., bed rest, physical therapy, medications and/or spinal injections) for a period of six months. * If of childbearing potential, patient is non-pregnant, non-nursing and agrees not to become pregnant for one year following surgery. * Is willing to and able to comply with the study plan and able to understand and sign the Patient Informed Consent Form. Exclusion Criteria: * Has had previous failed attempts at fusion surgery at the involved level(s). * Has a diagnosis of spinal infection tumour or trauma. * Requires surgery at more than two (2) levels. * Has osteoporosis (excluding osteopenia) as evidenced on plain X-rays, CT scans (or DEXA scan in cases of doubt). * Is pregnant. * Is an alcohol and/or drug abuser as defined by currently undergoing treatment for alcohol and/or drug abuse. * Has received drugs that may interfere with bone metabolism within two weeks prior to the planned surgery date (e.g., steroids or methotrexate) excluding routine perioperative, non-steroidal anti-inflammatory drugs. * Has a history of autoimmune disease. * Has a history of exposure to injectable collagen implants. * Has a history of hypersensitivity to protein pharmaceuticals (monoclonal antibodies or gamma globulins) or collagen. * Has received treatment with an investigational therapy (device and/or pharmaceutical) within 30 days prior to surgery or such treatment is planned during the 24 months following surgery. * Has received any previous exposure to any/all BMPs of either human or animal extraction. * Has a history of allergy to bovine products or a history of general anaphylaxis. * Has a history of any endocrine or metabolic disorder known to affect osteogenesis (e.g., Paget's disease, renal oseodystrophy, Ehlos-Danlos syndrome or osteogenesis imperfecta). * Has any disease that would preclude accurate clinical evaluation (e.g., neuromuscular disease, etc.). * Has a primary diagnosis of a spinal disorder other than degenerative disc disease or other conditions as set out in "inclusions" above at the involved level(s). * Has a condition that requires postoperative medications that interfere with fusion, such as steroids or prolonged use of non-steroidal anti-inflammatory drugs, excluding routine perioperative non-steroidal anti-inflammatory drugs. This does not include low dose aspirin for prophylactic anticoagulation. * Has overt or active bacterial infection, local or systemic, and/or a potential for bacteremia. * Has presence of active malignancy or prior history of malignancy (except for basal cell carcinoma of the skin). * Has a documented metal allergy or intolerance to titanium alloy or cobalt-chrome-molybdenum alloy. * Is, in the opinion of the Principal Investigator or Co-Investigators, intellectually unable to co-operate with the study. * Has chronic or acute renal and/or hepatic failure or prior history of renal or hepatic disease.