Evaluating The Safety and Effectiveness of The NeoDisc™ Versus ACDF in Subjects With Single-Level Cervical Disc Disease

The NeoDisc is an artificial cervical intervertebral disc replacement intended for clinical use following a discectomy. Implantation of the device will result in artificial replacement of a pathologically damaged or surgically removed cervical disc. Use of the device also obviates the need to harvest bone graft from the patient's iliac crest, a common and painful part of current surgical techniques.

The NeoDisc is indicated for cervical spinal arthroplasty in skeletally mature subjects with symptomatic cervical disc disease at one level from C3 to C7. Symptomatic cervical disc disease is defined as image-confirmed herniated disc, spondylosis, and/or loss of disc height, with functional neurological deficit (i.e., exhibits at least one sign associated with cervical level to be treated, including abnormal reflex, decreased motor strength, abnormal dermatome sensitivity, or pain in a dermatomal distribution).

Inclusion criteria

• 18-60 years of age (inclusive and skeletally mature)
• Diagnosis of symptomatic cervical disc disease, defined as image- confirmed pathology: herniated disc, spondylosis, and/or loss of disc height. Spondylosis is defined as MRI or CT-confirmed disc dessication, loss of disc height, bridging osteophytes, and/or uncovertebral arthrosis. Loss of disc height is specified as a measurement of at least 25% less than an adjacent nonsymptomatic level, but with a minimum of 1mm height remaining.
• Functional neurological deficit (i.e., exhibits at least one sign associated with cervical level to be treated, including abnormal reflex, decreased motor strength, abnormal dermatome sensitivity, or pain in a dermatomal distribution)
• Symptomatic level is C3-4, C4-5, C5-6 or C6-7 (one level)
• Preop NDI ≥30 points
• Unresponsive to conservative treatment for ≥6 wks, or exhibits progressive symptoms or signs of nerve root or spinal cord compression in the face of conservative treatment
• Not pregnant, nor interested in becoming pregnant within the follow-up period of the study
• Willing and able to comply with the requirements defined in the protocol for the duration of the study
• Signed and dated Informed Consent

Exclusion criteria

• Prior cervical fusion surgery at the operative level
• Prior cervical laminectomy at the operative level (prior cervical laminotomy need not be excluded)
• Prior cervical complete facetectomy at the operative level
• Requiring surgical treatment that would leave the patient with a postoperative deficiency of the posterior elements
• Radiographic signs of significant instability at operative level (greater than 3mm translation, > 11 degrees rotation different from adjacent level)
• Bridging osteophytes or motion < 2 degrees
• Radiographic confirmation of significant facet joint disease or degeneration
• Chronic neck or arm pain of unknown etiology
• Clinically significant symptomatic myelopathy (e.g., those with signal changes in the spinal cord on preoperative T2-weighted MRI)
• Cervical fracture, anatomic anomaly, or deformity (e.g. ankylosing spondylitis, scoliosis) at the levels to which the prosthesis will be attached
• Severe spondylolisthesis (>grade 1)
• Endocrine disorders or connective tissue diseases
• Rheumatoid arthritis or other autoimmune disease
• Progressive neuromuscular disease, e.g., muscular dystrophy, multiple sclerosis
• Chronic steroid users
• Taking any medications or drugs that are known to potentially interfere with the bone metabolism or soft tissue healing, which may include (but is not limited to) the following: inhaled glucocorticoids for asthma, corticosteroids, thyroid hormones, blood thinners (heparin, warfarin), gonadotropin-releasing hormone agonists for prostate cancer treatment, contraceptive medroxyprogesterone, lithium for bi-polar disorder treatment, anticonvulsants, aluminum-containing antacids, tetracycline
• Osteopenia, osteoporosis, or osteomalacia to a degree that spinal instrumentation would be contraindicated (DEXA T-score less than or equal to -2.5; DEXA necessary only if patient exhibits risk factors for low bone mass as quantified in DEXA screening questionnaire).
• Diabetes mellitus requiring insulin management
• Presence of metastases or active spinal tumor malignancy
• Body Mass Index (BMI) > 40
• Active local or systemic infection, including AIDS, hepatitis
• Having been enrolled in another investigational device study within the last 90 days
• Having had another cervical device implanted that would interfere with the surgical approach, study or control device, or follow-up evaluations.
• Demonstrates signs of nonorganic behavior, such as Waddell's signs
• History of substance abuse
• Involved in spinal litigation
• Mentally incompetent
• Incarcerated