Table 1.
Comparative summary of patients with and without implant failure
| Implant failure | No failure | Total | |
|---|---|---|---|
| Number of patients (%) | 6 (4.2) | 136 | 142 |
| Gender | |||
| Male | 3 | 38 | 41 |
| Female | 3 | 98 | 101 |
| Mean age | 61 (45–70) | 59 (16–84) | 59 (16–84) |
| Diagnosis | |||
| RA(AAS/SAS/VS) | 5 (6.3%) | 75 | 80 |
| Spinal tumor | 0 | 15 | 15 |
| Cervical spondylotic myelopathy | 0 | 10 | 10 |
| Athetotic myelopathy | 1 (11) | 8 | 9 |
| Os odontoideum | 0 | 6 | 6 |
| Dens fracture | 0 | 5 | 5 |
| Other | 0 | 17 | 17 |
| Fixation level | |||
| Cervical | |||
| C1–2 | 1 | 65 | 66 |
| C–T | 1 | 12 | 13 |
| Other | 1 | 25 | 26 |
| Occipital | |||
| O–C | 2 | 25 | 27 |
| O–C–T | 1 | 9 | 10 |
| Fixation range* | |||
| 2 | 1 | 69 | 70 |
| 3 | 1 | 20 | 21 |
| 4 | 0 | 3 | 3 |
| 5 | 0 | 11 | 11 |
| 6 | 1 | 12 | 13 |
| 7 | 0 | 6 | 6 |
| ≧8 | 3 | 15 | 18 |
* Fixation range means the number of levels of instrumentation