Table 3.
Univariate and multivariate Cox regression analysis identifying factors associated with IF.
| Characteristics | Unadjusted HR (95% CI) |
P | Adjusted HR (95% CI) |
P |
|---|---|---|---|---|
| Age, years | ||||
| < 50 | 1.000 | 1.000 | ||
| ≥ 50 | 1.655 (0.688–3.983) | 0.261 | 1.74 (0.545–5.556) | 0.350 |
| Sex | ||||
| Female | 1.000 | 1.000 | ||
| Male | 1.194 (0.513–2.776) | 0.681 | 0.846 (0.239–2.990) | 0.795 |
| BMI, kg/m2 | ||||
| < 24 | 1.000 | 1.000 | ||
| ≥ 24 | 1.171 (0.451–3.041) | 0.745 | 2.525 (0.454–14.039) | 0.290 |
| Tumor histological type | ||||
| Primary | 1.000 | 1.000 | ||
| Metastasis | 0.753 (0.284–1.996) | 0.568 | 2.451 (0.549–10.943) | 0.240 |
| Surgical type | ||||
| Total en bloc spondylectomy | 1.000 | 1.000 | ||
| Total piecemeal spondylectomy | 1.038 (0.303–3.552) | 0.953 | 4.715 (0.705–31.522) | 0.110 |
| Resected vertebral level | ||||
| Thoracic | 1.000 | 1.000 | ||
| Lumbar | 0.817 (0.324–2.061) | 0.817 | 1.912 (0.357–10.243) | 0.449 |
| Resection of thoracolumbar junctional region (T12 and/or L1) | ||||
| No | 1.000 | 1.000 | ||
| Yes | 2.556 (1.039–6.285) | 0.041* | 21.622 (3.567–131.084) | 0.001* |
| Number of resected vertebrae | ||||
| 1 | 1.000 | 1.000 | ||
| ≥2 | 0.914 (0.309–2.705) | 0.871 | 0.205 (0.023–1.836) | 0.157 |
| Number of instrumented vertebrae | ||||
| ≤4 | 1.000 | 1.000 | ||
| ≥5 | 2.605 (0.952–7.127) | 0.062 | 2.816 (0.444–17.869) | 0.272 |
| Instrumentation spanning junctional region | ||||
| No | 1.000 | 1.000 | ||
| Yes | 1.171 (0.505–2.715) | 0.712 | 0.323 (0.062–1.676) | 0.178 |
| Implant type | ||||
| Expandable titanium cage | 1.000 | 1.000 | ||
| Titanium mesh cage | 2.620 (0.867–7.916) | 0.088 | 8.315 (1.482–46.645) | 0.016* |
| Bone cement augmentation around the cage | ||||
| No | 1.000 | 1.000 | ||
| Yes | 0.037 (0.008–0.164) | <0.001* | 0.015 (0.002–0.107) | <0.001* |
IF: implant failure; BMI: body mass index; HR: hazard ratio; CI: confidence interval.