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

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.