新型钛合金金属橡胶颈椎间盘假体生物力学分析

Biomechanical analysis of a new titanium rubber cervical disc prosthesis

中文关键词:  金属橡胶  人工颈椎间盘  生物力学  脊柱稳定性

英文关键词:Metal rubber cervical disc prosthesis  Artificial cervical disc  Biomechanics  Spine stability

中文摘要:

  【摘要】 目的：评估新型钛合金金属橡胶颈椎间盘假体的生物力学性能。方法：特殊绕丝机制作新型金属橡胶颈椎间盘假体，电镜观察假体表面结构并对假体力学性能、疲劳特性进行测试；将24个新鲜羊颈椎依次按C4/5完整标本、髓核摘除、假体置换、椎间盘切除植骨融合内固定（ACDF）处理后，给予2.5Nm载荷，分别测量其在屈曲、后伸、左右侧屈及左右旋转时的位移，通过计算得出角度变化值，观察置换节段和相邻上下节段的运动范围（ROM）。结果：假体孔隙率为60%～80%，孔径大小90～500μm，弹性模量7MPa，疲劳试验（循环极限次数500×104次，极限载荷设置为200N）后未见假体断裂、高度降低。手术节段ROM测定显示，髓核摘除组各向ROM均显著大于完整组（P＜0.05），ACDF组的各向ROM均显著小于完整组（P＜0.05），而假体置换组各向ROM均与完整组无显著性差异（P＞0.05）。对于相邻上位节段，假体置换组各向ROM与完整组无明显差异（P＞0.05），而ACDF组ROM则大于完整组（P＜0.05）。相邻下位节段，假体置换组前屈ROM与完整组相比无明显差异，后伸ROM小于完整组（P＜0.05），侧屈、扭转时ROM较完整组增加（P＜0.05），但变化幅度小于ACDF组（P＜0.05）。结论：钛合金金属橡胶人工颈椎间盘假体保留了手术节段活动度，置入后对相邻椎间节段活动度及力学影响小，理论上可以成为较好的颈椎间盘置换假体。

英文摘要:

  【Abstract】 Objectives: To evaluate the biomechanical properties of a new titanium rubber cervical disc prosthesis. Methods: A new metal rubber cervical disc prosthesis was produced, the electron microscope was used to observe the prosthesis′ surface structure, and the mechanical properties as well as the fatigue properties were tested. 24 fresh sheep cervical spine specimens were used, and procedured by C4/5 intact, replacement, artificial disc replacement(ADR), anterior cervical discectomy and fusion(ACDF) treatment subsequently, 2.5Nm stress was added as load simulation, the range of motion(ROM) of the involved segment and adjacent segments were measured in flexion, extension, lateral bending and rotation. Results: The prosthesis had a porosity rate of 60%-80%, the pore size was 90-500μm, and the elastic modulus amount was about 7MPa. After the fatigue test(cycle times of 500×104 times, the limit load was 200N), there was no incidence of prosthesis fracture or no height loss. The ROM in the replacement group was significantly greater than that of the intact group(P<0.05), the ROM of the ACDF group was significantly less than that of the intact group(P<0.05), while the ADR group showed no significant difference compared with the intact one(P>0.05). For the superior adjacent segment, no significant difference was noted between the ADR group and intact group(P>0.05), while the ROM of ACDF group was greater than that of the intact group(P<0.05). For the inferior adjacent segment, in ADR group, there was no difference in flexion compared wtih intact group(P>0.05), extension ROM less than intact group(P<0.05), lateral bending and torsionmotion more than intact group(P<0.05), but the change was smaller than the ACDF group(P<0.05). Conclusions: The titanium rubber artificial cervical disc prosthesis is a new homogeneous elastic porous material which can reconstruct the cervical spine stability and preserve the ROM.