No more than 1 vertebral level may have DDD, and all diseased levels must be treated
Patients with involved vertebral endplates dimensionally smaller than 34.5 mm in the medial-lateral and/or 27 mm in the anterior-posterior directions
Known allergy to titanium, polyethylene, cobalt, chromium or molybdenum
Prior fusion surgery at any vertebral level
Clinically compromised vertebral bodies at the affected level due to current or past trauma
Radiographic confirmation of facet joint disease or degeneration
Lytic spondylolisthesis or spinal stenosis
Degenerative spondylolisthesis of grade > 1
Back or leg pain of unknown etiology
Osteopenia or osteoporosis: A screening questionnaire for osteoporosis, SCORE (Simple Calculated Osteoporosis Risk Estimation), will be used to screen patients to determine if a DEXA scan is required. If DEXA is required, exclusion will be defined as a DEXA bone density measured T score < -2.5.
Paget's disease, osteomalacia or anything other metabolic bone disease (excluding osteoporosis which is addressed above)
Morbid obesity defined as a body mass index > 40 or a weight more than 100 lbs. over ideal body weight
Pregnant or interested in becoming pregnant in the next 3 years
Active infection – systemic or local
Taking medication or any drug known to potentially interfere with bone/soft tissue healing (e.g., steroids)
Rheumatoid arthritis or other autoimmune disease
Systemic disease including AIDS, HIV, Hepatitis
Active malignancy: A patient with a history of any invasive malignancy (except non-melanoma skin cancer) unless he/she has been treated with curative intent and there has been no clinical signs or symptoms of the malignancy for at least 5 years
