Table 1.

Patient selection criteria

Criteria
Inclusion
21–70 years of age
Single-level symptomatic cervical disc disease between C3 and C7
Failed non-surgical treatment of at least 6 weeks, or subject has progressive symptoms of nerve root or spinal cord compression
Minimum Neck Disability Index score of ≥30 % (15/50)
Exclusion
Cervical instability defined by translation on flexion–extension radiographs of 3 mm or 11° compared with adjacent level
Non-mobility of the level to be treated
Fused adjacent level to the level to be treated
Axial neck pain as the solitary symptom
Prior surgery at target levels
Metabolic bone disease or endocrine disorder affecting osteogenesis
Pre-existing neurological abnormalities other then deficits produced from the spinal lesion
Alcohol or drug abuse
Pregnant or wishing to become pregnant within 5 years
Traumatic injury of spine
HIV, metastatic cancer, presence of infection, morbid obesity, significant psychological disease or allergy to a metal alloy or polyethylene