The purpose of this study is to find out if use of a cervical disc prosthesis in the treatment of a cervical disc herniation preserves or restores normal mobility and movement in the cervical spine.

Intractable nerve pain to the arm caused by a cervical disc herniation is typically treated by removal of the protruding disc through an operation. Fusion of the discs follows in about 70% of cases.

Adjacent disc disease (ADD), symptomatic degenerative changes in the levels adjacent to the operated level is regarded as a late complication. Fusion at the operated level is thought to contribute to this process due to compensative increased mobility and stress on the adjacent segments.

Keeping the operated segment mobile through the use of a cervical disc prosthesis possibly prevents ADD.

We hypothesize that use of a cervical disc prosthesis preserves or restores normal mobility to the cervical spine. To test this hypothesis subjects are randomised in a group receiving a standard anterior cervical discectomy, and a group receiving a standard discectomy with placement of a cervical disc prosthesis. Digital X-ray cinematographic videos are made of a flexion/extension movement. The videos will be analyzed manually and through a newly designed automated program, to check for mobility and order of movement.

Inclusion Criteria:

• indication for anterior cervical discectomy
• monoradicular syndrome caused by compression at C5-6 or C6-7
• monosegmental disease on MRI
• able to actively perform flexion/extension movement
• segmental mobility on the afflicted level >2 degrees of rotation
• informed consent

Exclusion Criteria:

• previous operative interventions on the cervical spine
• multiple segments afflicted
• positive L'Hermittes sing
• Active infection
• Immature bone
• Tumorous processes in the cervical region
• Previous radiation therapy in the cervical region
• Pregnancy
• Cervical myelopathy
• not able to speak Dutch