Safety and Efficacy Study Comparing ProDisc-C to ACDF Surgery to Treat SCDD

Inclusion Criteria: Symptomatic cervical disc disease (SCDD) in one vertebral level between C3-C7 defined as: Neck or arm (radicular) pain; and/or a functional/neurological deficit with at least one of the following conditions confirmed by imaging (CT, MRI or X-rays): Herniated nucleus pulposus; Spondylosis (defined by the presence of osteophytes); and/or Loss of disc height. Age between 18 and 60 years. Unresponsive to non-operative treatment for approximately six weeks or has the presence of progressive symptoms or signs of nerve root/spinal cord compression in the face of conservative treatment. NDI score greater than or equal to 15/50 (30%). Psychosocially, mentally and physically able to fully comply with the protocol including adhering to follow-up schedule and requirements and filling out forms. Signed informed consent. Exclusion Criteria: More than one vertebral level requiring treatment. Marked cervical instability on resting lateral or flexion/extension radiographs: translation greater than 3mm and/or greater than 11 degrees of rotational difference to that of either adjacent level. Has a fused level adjacent to the level to be treated. Radiographic confirmation of severe facet joint disease or degeneration. Known allergy to cobalt, chromium, molybdenum, titanium or polyethylene. Clinically comprised vertebral bodies at the affected level(s) due to current or past trauma, e.g. by the radiographic appearance of fracture callus, malunion or nonunion. Prior surgery at the level to be treated. Severe spondylosis at the level to be treated as characterized by any of the following: Bridging osteophytes; A loss of disc height greater than 50%; or Absence of motion (<2°). Neck or arm pain of unknown etiology. Osteoporosis: A screening questionnaire for osteoporosis, SCORE (Simple Calculated Osteoporosis Risk Estimation), will be used to screen patients who require a DEXA (dual energy x-ray absoptiometry) bone mineral density measurement. If DEXA is required, exclusion will be defined as a DEXA bone density measured T score less than or equal to -2.5 (the World Health Organization definition of osteoporosis). Paget's disease, osteomalacia or any other metabolic bone disease (excluding osteoporosis which is addressed above). Severe diabetes mellitus requiring daily insulin management. Pregnant or interested in becoming pregnant in the next three years. Active infection - systemic or local. Taking medications 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 have been no clinical signs or symptoms of the malignancy for at least 5 years.