颈椎人工髓核柔性稳定系统的生物力学研究

A biomechanical study of cervical spine following insertion of the anterior spine instrumentation system combing prosthetic disc nucleus with flexible stabilization devices in vitro

目的评价植入人工髓核柔性稳定一体化系统的颈椎节段的稳定性。方法采用6具新鲜尸体颈椎功能单位,分为四个试验组:完整组(A组)、摘除髓核组(B组)、柔性稳定组(C组)和人工髓核组(D组)。施加最大载荷为2·0N·m的6种力偶,使脊柱产生前屈、后伸,左、右侧弯和左、右轴向旋转运动。记录不同运动状态下节段的运动范围(ROM)和中性区(NZ)参数变化情况;在0N和100N轴向载荷下测量四组标本的椎间隙高度变化。结果柔性稳定组同完整组相比较差异无显著意义(P>0·05),髓核摘除组同完整组比较差异有显著意义(P<0·01);人工髓核组同完整组相比较,颈椎后伸活动度增加,差异有显著意义(P<0·01)。髓核摘除组0N载荷下椎间隙高度平均下降1·5mm,加载100N负荷后,椎间隙高度平均下降2·0mm;柔性系统组和单纯髓核组,0N载荷下,椎间隙高度较正常平均升高0·5mm,100N载荷下椎间隙高度较正常组平均升高0·3mm。结论颈椎间盘摘除术后植人工髓核柔性稳定一体化系统能满足颈椎的稳定性和恢复椎间高度。

Objective To evaluate the stability mechanical functions of the anterior spine instrumentation system combing prosthetic disc nucleus with flexible stabilization devices. Methods The experiment was carried out with 6 fresh cervical spine specimens being used as functional units, which established 4 groups： normal,nucleotomy, flexible stabilization system, and prosthetic disc nucleus. A three-dimensional movement device, with the maximum loading of 2. 0N·m was applied to produce six kinds of pure moment of force to create six kinds of movement of the cervical spine in flexion, extension,left and right lateral bending, and left and right axial rotation. The changes of the range of rnovement（ROM） and neutral zone（NZ） were measured. With and without a follower preload of 100N, changes in disc height were measured. Results All the measurements in the flexible stabilization system was not statistically significant from that of the normal group（P 〉 0.05 ） while the difference between the normal and the nucleotomy group was statistically significant（P〈0.01）. Compared with the normal group, the range of extension in prosthetic disc nucleus was increased and had statistically significance （P 〈0.01）. In the nucleotomy group, the height between discs reduced 1.5mm averagely with ON preload,and 2.0mm averagely with 100N preload,while in the flexible stabilization system and prosthetic disc nucleus group, it increased 0.5mm and 0.3mm respectively on average. Conclusion The anterior spire instrumentation system combing prosthetic disc nucleus with flexble stabilization devices can restore the stability and disc height after nucleotomy.