Surgical treatment
| Primary surgical procedure |
1974–82 cohort (n=32) |
1991–96 cohort (n=27) |
| Anterior fusion | 1 | 0 |
| Anterior discetomy and fusion | 0 | 1 |
| Anterior discectomy | 0 | 1 |
| Posterior fusion C1–2 | 12 | 12 |
| Posterior fusion + laminectomy | 4 | 0 |
| Anterior decompression + fusion + posterior fixation | 0 | 5 |
| Occipitocervical fusion | 12 | 6 |
| Occipitocervical fusion + laminectomy | 1 | 0 |
| Other | 0 | 2 |
| Not recorded | 2 | 0 |