胸腰椎前后路短节段内固定器的生物力学评价及其意义

为了对比研究胸腰椎前后路内固定器的生物力学特性，为临床选择提供依据，我们采用人尸体脊柱标本进行离体生物力学实验，了解Kaneda和AF器械的稳定能力和载荷屈服强度。结果显示半椎体切除模型，AF在屈伸和左侧弯方向上的稳定性优于Kaneda(P<0.05)；全椎体切除模型，AF在屈曲、左侧弯和轴向旋转方向上优于Kaneda(P<0.01)。从失稳趋势分析，椎体全切除时，Kaneda抗旋转稳定性明显下降，AF则无明显变化。Kaneda、AF和对照组平均屈服强度(M)分别为477.3、544.4、493.6kg，两实验组失稳时无器械的变形和松动。这一结果表明，AF器械的稳定性优于Kaneda；全椎体切除使Kaneda旋转失稳；两器械均可有效恢复脊柱的承载能力。

Biomechanical Studies on Two Thoracolumbar Implants in Cadaveric Spine

The aim of these studies was to evaluate the biomechanical characteristics of two devices and provide information for clinical choice. In vitro cadaveric spine testing which consisted of the stability test and the yield strength test was performed. In hemicorpectomy model, the AF was stiffer than the Kaneda in flexion, extension and left lateral bending ( P <0.01). In total corpectomy model, the AF was stiffer than the Kaneda in flexion,left lateral bending and axial rotation ( P <0.01). The average values of yield strength(M) for the Kaneda,the AF and the intact were 477.3 kg,544.4 kg and 493.6 kg resectively. The stability of the AF is superior to that of the Kaneda. In total corpectomy, the Kaneda is significantly unstable in axial rotation. Both devices restore effectively load carrying capacity of the spine.