M6-C Artificial Cervical Disc Two-Level IDE Pivotal Study

Inclusion Criteria:

• Diagnosis of degenerative cervical radiculopathy with or without spinal cordcompression requiring surgical treatment at two contiguous levels from C3 to C7demonstrated 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 historyand radiographic studies (e.g. MRI, CT, x-rays, etc.)

• Inadequate response to conservative medical care over a period of at least 6 weeksor have the presence of progressive symptoms or signs of nerve root/spinal cordcompression 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-uprequirements

• 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 levelsrequiring surgery

• Previous anterior cervical spine surgery

• Axial neck pain as the solitary symptom

• Previous posterior cervical spine surgery (such as a posterior elementdecompression) 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 theindex or adjacent levels as indicated on flexion/extension x-rays.

• Advanced degenerative changes (e.g., spondylosis) at either of the index vertebrallevels as evidenced by bridging osteophytes, central disc height less than 4millimeters and/or < 50% of the adjacent normal intervertebral disc, or kyphoticdeformity > 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 thecervical 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 affectbone and mineral metabolism

• Taking medications that may interfere with bony/soft tissue healing includingchronic steroid use

• Known allergy to titanium, stainless steels, polyurethane, polyethylene, or ethyleneoxide residuals

• Fibromyalgia, Rheumatoid Arthritis (or other autoimmune disease), or a systemicdisorder such as HIV or acute hepatitis B or C.

• Insulin dependent diabetes

• Medical condition (e.g., unstable cardiac disease, cancer) that may result inpatient 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 patientself-assessment of function, pain or quality of life.

• Involved in current or pending spinal litigation where permanent disability benefitsare being sought.

• Incarcerated at time of study enrollment

• Current participation in other investigational study.