Table 1

Study Inclusion and Exclusion Criteria

Inclusion criteria

  • Age 18-69 years

  • Symptomatic cervical degenerative disc disease in only one level between C3-C7 with:

    • Neck and/or arm pain and/or

    • Decreased muscle strength and/or

    • Abnormal sensation and/or abnormal reflexes

  • Deficit confirmed by imaging (CT, MRI, or X-ray)

  • NDI score of ≥ 30

  • Unresponsive to non-operative, conservative treatment for at least 6 weeks or presence of progressive symptoms or signs of nerve root/spinal cord compression despite continued non-operative treatment

  • No prior surgery at the operative level and no prior cervical fusion procedure at any level

  • Physically and mentally able and willing to comply with the protocol

  • Signed informed consent

  • Willingness to discontinue all use of non-steroidal anti-inflammatory drugs (NSAIDs) from one week before surgery until 3 months after surgery

Exclusion criteria

  • More than one vertebral level requiring treatment/immobile level between C1 and C7 from any cause

  • Any prior spine surgery at operative level of any prior cervical fusion at any level

  • Disc height less than 3 mm

  • T-score less than -1.5 (osteoporosis evaluation)

  • Paget's disease, osteomalacia, or any other metabolic bone disease other than osteoporosis

  • Active systemic infection of surgical site or history of or anticipated treatment for systemic infection including HIV/Hepatitis C

  • Active malignancy: a history of any invasive malignancy (except non-melanoma skin cancer), unless treated with curative intent and there had been no clinical signs or symptoms of the malignancy > 5 years

  • Marked cervical instability on resting lateral or flexion-extension radiographs

  • Known allergy to cobalt, chromium, molybdenum, or polyethylene

  • Segmental angulation of greater than 11° at treatment or adjacent levels

  • Rheumatoid arthritis, lupus, or other autoimmune disease

  • Any diseases or conditions that would preclude accurate clinical evaluation

  • Daily, high-dose oral and/or inhaled steroids or a history of chronic use of high dose steroids

  • BMI > 40

  • Use of any other investigational drug or medical device within 30 days prior to surgery

  • Pending personal litigation relating to spinal injury (worker's compensation not included)

  • Smoking more than one pack of cigarettes per day

  • Reported to have mental illness or belonged to a vulnerable population