Table 1 Inclusion criteria of patients to groups with different surgical methods

ACDF

1. One or two level of cervical spinal cord compression is shown by the magnetic resonance imaging

2. No abnormalities were reported by other specialists from neurology, ophthalmology, cardiovascular and otolaryngology.

3. No improvement of symptoms was achieved after at least 3 months of conservative treatment.

4. Have no history of cervical surgery.

5. Patient chose ACDF over TDR.

TDR

1. One or two level of cervical spinal cord compression is shown by the MRI

2. Myelopathy or refractory radiculopathy due to degenerative disc disease confirmed by magnetic resonance imaging and/or computed tomography myelogram

3. No abnormalities were reported by other specialists from neurology, ophthalmology, cardiovascular and otolaryngology.

4. No obvious facet joint arthrosis and no instability was found in the cervical spine.

5. Have no history of cervical surgery

6. Patient chose TDR over ACDF

Laminoplasty

1. More than two level of cervical spinal cord compression is shown by the MRI

2. Abnormalities of neurology, ophthalmology, cardiovascular, otolaryngology were excluded

3. No improvement of the symptom after at least 3 months of conservative treatment.

4. Have no history of cervical surgery.

5.Patient agreed to receive open door laminoplasty