Prospective, concurrently controlled, multi-center study to evaluate the safety and effectiveness of the Spinal Kinetics M6-C™ artificial cervical disc compared to anterior cervical discectomy and fusion (ACDF) for the treatment of contiguous two-level symptomatic cervical radiculopathy at vertebral levels from C3 to C7 with or without spinal cord compression.

Patients will be concurrently enrolled in the M6-C treatment group and the ACDF control group. Patients should have failed at least six weeks of conservative treatment or demonstrate progressive symptoms despite continued non-operative treatment. For the study, 263 patients will undergo either a two-level cervical artificial disc procedure, or an instrumented (ACDF) procedure as per site group assignment. Patients will be evaluated clinically, radiographically, and via the collection of patient-reported outcomes at 6 Weeks, 3 Months, 6 Months, 12 Months and 24 Months. The primary endpoint is Overall Success at 24 Months.

Inclusion Criteria:

• Diagnosis of degenerative cervical radiculopathy with or without spinal cord compression requiring surgical treatment at two contiguous levels from C3 to C7 demonstrated by signs and/or symptoms of disc herniation and/or osteophyte formation (e.g. neck and/or arm pain, radiculopathy, etc.) and is confirmed by patient history and radiographic studies (e.g. MRI, CT, x-rays, etc.)
• Inadequate response to conservative medical care over a period of at least 6 weeks or have the presence of progressive symptoms or signs of nerve root/spinal cord compression in the face of continued non-operative management
• Neck Disability Index score of ≥ 30% (raw score of ≥ 15/50)
• Neck or arm pain Visual Analog Scale Score ≥ 4 on a scale of 0 to 10
• Willing and able to comply with the requirements of the protocol including follow-up requirements
• Willing and able to sign a study specific informed consent
• Skeletally mature and at least 18 years old but not older than 75 years old

Exclusion Criteria:

• More than two cervical levels requiring surgery, or two non-contiguous levels requiring surgery
• Previous anterior cervical spine surgery
• Axial neck pain as the solitary symptom
• Previous posterior cervical spine surgery (such as a posterior element decompression) that destabilizes the cervical spine
• Advanced cervical anatomical deformity (such as ankylosing spondylitis, scoliosis) at either of the operative levels or adjacent levels
• Symptomatic facet arthrosis
• Less than four degrees of motion in flexion/extension at either of the index levels
• Instability as evidenced by subluxation greater than 3 millimeters at either of the index or adjacent levels as indicated on flexion/extension x-rays.
• Advanced degenerative changes (e.g., spondylosis) at either of the index vertebral levels as evidenced by bridging osteophytes, central disc height less than 4 millimeters and/or < 50% of the adjacent normal intervertebral disc, or kyphotic deformity > 11 degrees on neutral x-rays
• Severe cervical myelopathy (i.e., Nurick's Classification greater than 2)
• Active systemic infection or infection at the operative site
• Co-morbid medical conditions of the spine or upper extremities that may affect the cervical spine neurological and/or pain assessment
• Metabolic bone disease such as osteoporosis that contradicts spinal surgery
• History of an osteoporotic fracture of the spine, hip or wrist
• History of an endocrine or metabolic disorder (e.g. Paget's disease) known to affect bone and mineral metabolism
• Taking medications that may interfere with bony/soft tissue healing including chronic steroid use
• Known allergy to titanium, stainless steels, polyurethane, polyethylene, or ethylene oxide residuals
• Fibromyalgia, Rheumatoid Arthritis (or other autoimmune disease), or a systemic disorder such as HIV or acute hepatitis B or C.
• Insulin dependent diabetes
• Medical condition (e.g., unstable cardiac disease, cancer) that may result in patient death or have an effect on outcomes prior to study completion
• Pregnant, or intend to become pregnant, during the course of the study
• Severe obesity (Body Mass Index greater than 45)
• Physical or mental condition (e.g. psychiatric disorder, senile dementia, Alzheimer's disease, alcohol or drug addiction) that would interfere with patient self-assessment of function, pain or quality of life.
• Involved in current or pending spinal litigation where permanent disability benefits are being sought.
• Incarcerated at time of study enrollment
• Current participation in other investigational study.

Participants will be assigned a treatment group by enrolling site and will not be blinded to the treatment group assignment before their surgery. Investigator, and site will not be blinded to treatment assignment due to the need to prepare for the respective surgery associated with the treatment assignment.