颈椎可调控式融合固定器山羊模型的生物力学对照研究

Biomechanics control study of goat cervical model implanted with anterior cervical-adjustable fusion fixator

目的 利用山羊颈椎模型分析比较颈椎可调控式融合固定器（AC-AFF）与其他内固定方式的生物力学差异.方法 将18只山羊随机分为3组,椎体次全切除后分别植入AC-AFF、钛网＋钢板或髂骨块＋钢板,人工饲养6个月后羊颈椎模型经处理再进行生物力学测试,施加载荷为0～150N,加载速率为1.4mm/min,测试的运动工况包括颈椎前屈、后伸、侧屈及旋转,测量指标包括颈椎的变形与位移、强度和刚度及极限力学性能.结果 三种重建方式中,AC-AFF组在相同载荷作用下应变最小,较钛网＋钢板组、髂骨块＋钢板组分别小2%～4%（P＞0.05）及10%～16%（P＜0.05）;在轴向压缩、前屈、后伸或侧屈状态下植骨融合处的应力集中最小;平均水平位移AC-AFF组为0.44 mm,钛网＋钢板组为0.51 mm,髂骨块＋钢板组为0.70 mm.轴向位移AC-AFF较钛网＋钢板小3%～4%（P＞0.05）,较髂骨块＋钢板小16%～24%（P＜0.05）;AC-AFF的水平剪切刚度、轴向刚度及弯曲刚度最高,扭矩及扭转刚度最大.极限破坏实验显示AC-AFF的极限载荷为1107 N,钛网＋钢板组为998 N,髂骨块＋钢板组为879 N.结论 与钛网＋钢板及髂骨块＋钢板比较,AC-AFF的生物力学稳定性更高.

Objective To compare the biomechanics difference among anterior cervical-adjustable fusion fixator （AC-AFF） and other cervical implant systems. Methods Eighteen experimental goats, respectively implanting the AC-AFF and titanium mesh or autogenous iliac bone combined cervical plate after corpectomy, were randomly divided to three groups and fed subsequently. Biomechanics control study of the goat cervical models was carried out 6 months later. Applied load was 0-150 N, loading rate was 1.4 mm/ min. The cervical spine deformation, displacement, strength, stiffness and ultimate mechanical properties were tested under the movement of cervical flexion, extension, lateral bending and rotation. Results Under the same load, the strain of AC-AFF group was least, less 2% -4% （P 〉 0.05） and 10% -16% （P 〈 0.05 ） than titanium mesh combined plate group and iliac bone combined plate group, respectively. The fusion interface stress of AC-AFF group also was least under the condition of axial compress, flexion, extension, and lateral flexion. The average horizontal displacement of AC-AFF group was 0.44 mm, 0.51 mm in titanium mesh combined plate group, and 0.70 mm in iliac bone combined plate group. The axial displacement of AC-AFF group was 3%-4% less than the titanium mesh combined plate group （P 〉 0.05） , and 16% -24% less than the iliac bone combined plate group （P 〈 0.05）. It was statistically shown that the level shearing stiffness, axial stiffness and bending stiffness were maximum in AC-AFF group. Ultimate destruction of experiments showed that the limit load in AC-AFF was 1107 N, 998 N in titanium mesh combined plate group, and 879 N in iliac bone block combined plate group. Conclusion AC-AFF is more superior to titanium mesh or autogenous iliac bone combined cervical plate in the biomechanical stability.