In order to improve osseointegration, polyetheretherketone (PEEK) interbody fusion cages are frequently surface coated. The bonding strength of the coatings is mostly investigated under unrealistic loading conditions. To close this gap, in this study, uncoated and coated cages were loaded in a clinical setup in order to investigate their real resistance against abrasion. Six uncoated, six calcium phosphate (CaP) nanocoated, and six titanium (Ti) nanocoated PEEK cages were tested in this study. The experimental setup was designed to mimic cage impaction into the intervertebral disc space using polyurethane (PU) foam blocks as vertebral body substitutes. The cage surface was inspected before and after impaction, and their weight was measured. Impaction resulted in abrasion at the tip of the ridges on the implant surface. The mean weight loss was 0.39 mg for the uncoated cages, 0.57 mg for the CaP nanocoated cages, and 0.75 mg for the Ti nanocoated cages. These differences were statistically significant. In conclusion, differences between the three cage types were found concerning the amount of abrasion. However, all three cages lost less weight than a comparative Ti plasma spray coated cage, which showed a mean weight loss of 2.02 mg. This may be because the plasma spray coating is significantly thicker than the two nanocoatings. If compared with the permitted amount of weight loss derived from an FDA guidance document, which is approximately 1.7 mg, the wear of the Ti plasma spray coated cage is above this limit, whereas the wear for all other cage types is below.

中文翻译：

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涂层聚醚醚酮腰椎椎间融合器在模拟撞击椎间盘空间下的耐磨性

为了改善骨整合，聚醚醚酮 (PEEK) 椎间融合器经常进行表面涂层。涂层的结合强度主要在不切实际的负载条件下进行研究。为了缩小这一差距，在本研究中，未涂层和涂层的笼子在临床设置中加载，以研究它们的真正耐磨性。本研究测试了六个未涂层、六个磷酸钙 (CaP) 纳米涂层和六个钛 (Ti) 纳米涂层 PEEK 笼。实验装置旨在使用聚氨酯 (PU) 泡沫块作为椎体替代品来模拟笼子撞击椎间盘空间。在撞击前后检查笼表面，并测量它们的重量。撞击导致种植体表面脊尖处的磨损。平均体重减轻为 0。无涂层笼为 39 mg，CaP 纳米涂层笼为 0.57 mg，Ti 纳米涂层笼为 0.75 mg。这些差异具有统计学意义。总之，在磨损量方面发现了三种保持架类型之间的差异。然而，所有三个笼子的重量损失都比对比钛等离子喷涂笼子少，后者的平均重量损失为 2.02 毫克。这可能是因为等离子喷涂涂层明显比两个纳米涂层厚。如果与 FDA 指导文件中允许的重量损失量（大约 1.7 毫克）相比，Ti 等离子喷涂保持架的磨损高于此限制，而所有其他保持架类型的磨损低于此限制。这些差异具有统计学意义。总之，在磨损量方面发现了三种保持架类型之间的差异。然而，所有三个笼子的重量损失都比对比钛等离子喷涂笼子少，后者的平均重量损失为 2.02 毫克。这可能是因为等离子喷涂涂层明显比两个纳米涂层厚。如果与 FDA 指导文件中允许的重量损失量（大约 1.7 毫克）相比，Ti 等离子喷涂保持架的磨损高于此限制，而所有其他保持架类型的磨损低于此限制。这些差异具有统计学意义。总之，在磨损量方面发现了三种保持架类型之间的差异。然而，所有三个笼子的重量损失都比对比钛等离子喷涂笼子少，后者的平均重量损失为 2.02 毫克。这可能是因为等离子喷涂涂层明显比两个纳米涂层厚。如果与 FDA 指导文件中允许的重量损失量（大约 1.7 毫克）相比，Ti 等离子喷涂保持架的磨损高于此限制，而所有其他保持架类型的磨损低于此限制。这表明平均体重减轻了 2.02 毫克。这可能是因为等离子喷涂涂层明显比两个纳米涂层厚。如果与 FDA 指导文件中允许的重量损失量（大约 1.7 毫克）相比，Ti 等离子喷涂保持架的磨损高于此限制，而所有其他保持架类型的磨损低于此限制。这表明平均体重减轻了 2.02 毫克。这可能是因为等离子喷涂涂层明显比两个纳米涂层厚。如果与 FDA 指导文件中允许的重量损失量（大约 1.7 毫克）相比，Ti 等离子喷涂保持架的磨损高于此限制，而所有其他保持架类型的磨损低于此限制。