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.