Table 2.
Comparison of different particulate implant materials with PEEK particles tested in the current investigation
| Particle type | Challenge location | Average particle size mn (μm) (range) |
Dose | Time in situ | Reaction | Ref |
|---|---|---|---|---|---|---|
| PEEK | Epidural | 1.2 μm (0.5–70) | 3 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 and TNF-α in peri-challenge tissue at 3 and 6 months | Current study |
| PEEK | Intradiscal | 1.2 μm (0.5–70) | 3 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 and TNF-α in peri-challenge tissue at 6 months | Current study |
| UHMWPE | Epidural | 1.2 μm (0.5–10) | 4 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 in peri-challenge tissue at 3 months (not at 6 months) | 36 |
| Stainless steel (316L) | Epidural | 0.1 μm (0.1–10) | 4 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 in peri-challenge tissue at 3 months (not at 6 months) | 36 |
| Titanium | Epidural | 0.2 μm (0.1–10) | 4 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 in peri-challenge tissue at 3 months (not at 6 months) | 36 |
| Nitinol (Ti35 %Ni) | Epidural | 100–300 μm (100–300) | 12 mg | 1, 4, 12, 26, and 52 weeks | No systemic toxicity or organ pathology. Moderate inflammation at 1–4 weeks progressing to mild inflammation by 52 weeks (histological evaluation of lymphocytes, plasma cells, macrophages and giant cells) | 30 |
| Nickel | Epidural | 0.6 μm (0.3–19) | 20 mg | 3 Days | Severe toxicity: neuropathy | 17 |
| Cobalt alloy | Epidural | 0.2 μm (0.1–3.3) | 2.5–10 mg | 3 and 6 months | No systemic toxicity or organ pathology. Elevated IL-6 and TNF-α in peri-challenge tissue at 3 and 6 months for >5 mg of particle challenge | 17 |
| Cobalt alloy | Epidural | 0.1 μm (0.1–10) | 4 mg | 3 and 6 months | No systemic toxicity or organ pathology. No elevation ins local tissue cytokine levels (IL-6, TNF-α, IL-1b, and IL-8) | 36 |