• Evaluation of device and/or procedure related adverse event(s) [ Time Frame: At 24-months ] [ Designated as safety issue: Yes ]
• Maintenance or improvement neurological status [ Time Frame: At 24-months ] [ Designated as safety issue: Yes ]
• Improvement in Neck Disability Index [ Time Frame: At 24 months ] [ Designated as safety issue: No ]
• Quantitative radiographic assessment of range of motion (ROM) and qualitative radiographic fusion assessment [ Time Frame: At 24-months ] [ Designated as safety issue: No ]

• Arm and neck pain as measured by Visual Analogue Scales (VAS) [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Odom's criteria score [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Nurick's Classification [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Overall Quality of Life (SF-36v2™) [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Disc height maintenance [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Pain medication use [ Time Frame: At 24-months ] [ Designated as safety issue: No ]
• Post-operative time to normal activity [ Time Frame: At 24 months ] [ Designated as safety issue: No ]
• Self-reported satisfaction with treatment [ Time Frame: At 24 months ] [ Designated as safety issue: No ]

The purpose of this study is to establish the safety and effectiveness of the Advent™ Cervical Disc compared to Anterior Cervical Discectomy and Fusion (ACDF) in treating degenerative disc disease at a single-level in the cervical spine (from C3 to C7) following cervical discectomy in skeletally mature patients (at least 18 years of age).

Following surgery study subjects will be evaluated at the following intervals: 6 wks (± 2wks); 3 Months (±2 wks); 6 Month (±1 months); 12 and 24 Month (±2 months) and annually until the last subject enrolled completes their 24 Month follow-up

• Device: Cervical Artificial Disc (Advent™ Cervical Disc)
• Device: ACDF (Hallmark™ Anterior Cervical Plate System with corticocancellous allograft bone)

• Experimental: Advent™ Cervical Disc
• Active Comparator: ACDF Control

Inclusion Criteria:

• One cervical spine level between C3 and C7 which requires surgical treatment for intractable cervical radiculopathy and/or myelopathy demonstrated by herniated disc, and/or osteophyte formation leading to nerve root and/or spinal cord compression confirmed by patient history (e.g. neck and/or arm pain), functional and/or neurological deficit (e.g. numbness, weakness, diminished or pathologic reflexes, gait disturbances, etc.) and radiographic studies (e.g. CT, MRI, x-rays, etc.).
• Unresponsive to conservative care over a period of at least 6 weeks
• Neck Disability Index score ≥ 15/50 (30%)
• Willing and able to comply with the requirements of the protocol including follow-up requirements and to sign a study specific informed consent

Exclusion Criteria:

• More than 1 level requiring surgical treatment for intractable cervical radiculopathy and/or myelopathy.
• Active local (at the proposed surgical site) or systemic infection
• Prior anterior neck surgery at any level.
• Prior posterior cervical spine surgery at the index level except posterior decompressive surgery where the posterior elements are preserved.
• Currently undergoing treatment for disease of the thoracic or lumbar spine.
• Axial neck pain as the primary diagnosis, without evidence of neural compression
• Significant cervical anatomical deformity
• Any anatomical consideration which in the investigators opinion would make the anterior cervical approach excessively risky or impossible
• Severe obesity defined as a Body Mass Index (BMI) > 40
• Instability on AP, lateral neutral or flex/ext images: ≥2mm translation relative to the adjacent segment, and/or ≥ 11 degrees relative to adjacent segments
• Central disc height ≤ 2mm
• Advanced spondylosis (i.e. facet joints degeneration, anterior or posterior bridging of the interspace or lack of motion on the pre-operative flexion/extension x-rays)
• Severe cervical myelopathy as indicated by: Signs and/or symptoms > 6months duration, Nurick's Classification grades IV or V, and/or Myelomalacia as evidence on a MRI
• Metabolic bone disease such as osteoporosis to a degree that spinal instrumentation is contra-indicated (Males over 55 years of age, females over 50 years of age and/or subjects that in the investigators opinion are medical indicative of osteoporosis (e.g. early menopause, steroid use, etc.) are required to have a DEXA scan; If the DEXA scan is ≤ -2.5t in the spine, the patient must be excluded)
• Allergy to any component of the device (titanium, polycarbonated polyurethane, polyethylene terephthalate, or ethylene oxide residuals)
• Chronic steroid or other medication use that may interfere with bony/soft tissue healing
• History of endocrine or metabolic disorders (e.g. Paget's disease) known to effect bone and mineral metabolism
• Autoimmune diseases e.g., ankylosing spondylitis, rheumatoid arthritis, etc.
• Insulin dependent diabetes mellitus
• Active malignancy
• Currently pregnant or considering becoming pregnant during the follow-up period
• Advanced emphysema, Alzheimer's disease or other medical conditions that would interfere with patient self-assessment of function, pain or quality of life
• Medical condition (e.g. unstable cardiac disease, end-stage cancer) that may result in patient death prior to study completion
• Chemical dependency (e.g. alcohol or narcotic addiction) problem that may interfere with study requirements
• Mental incompetence as determined by the Investigator which may effect participation in the study
• Incarcerated
• Involved in any current or pending litigation relating to a spinal condition
• Concurrently participating in any other investigational study
• Anatomy (e.g. endplate dimensions) at the index level not consistent with the dimensions of the implants available (e.g. based on pre-operative radiographic evaluations and templates in the surgical technique manual).