颈椎动态稳定器置入非融合颈椎的生物力学分析

背景：颈椎动态稳定器的解剖型设计与正常椎间盘应具有相似的生物力学特点,其动态性设计具有轴向顺应性以及震荡吸收功能,而前缘倒齿嵌入上下椎体可获得足够的轴向稳定性。目的：比较颈椎前路融合内固定和颈椎动态稳定器置入非融合后颈椎相关生物力学指标变化。方法：将6具新鲜人C2～ C7颈段脊柱标本随机分为3组,在完整颈椎测试后分别行C5、6前路减压颈椎动态稳定器DCI置入,C5、6前路减压单纯Cage融合内固定,C5、6前路减压颈椎前路一体化钢板椎间融合器融合内固定。检测各组标本前屈、后伸、左右侧屈不同生理运动工况并施加2.0N·m纯力偶矩,颈椎标本C5～ 6上下邻近节段手术前后活动度大小。结果与结论：3种内固定后C5～ 6上下邻近节段较正常颈椎标本前屈、后伸和左右侧屈关节活动度值均有所增加,且表现出良好的即时稳定性,但颈椎动态稳定器置入组最接近正常值;3组间C5～ 6上下邻近节段关节活动度差异无显著性意义。表明颈椎动态稳定器置入后对邻近节段椎体活动度无明显影响或影响甚小,在一定程度上减小假体与其邻近椎体轴向应力,有效地维持颈椎活动。

Biomechanical study on anterior decompression and non-fusion with dynamic cervical implant

BACKGROUND：The anatomical design of the dynamic cervical implant（DCI） has similar biomechanical characteristics to the normal disc.The dynamic design has axial compliance and shock absorption.And the front teeth down fitting into the upper and lower vertebral bodies can get sufficient axial stability.OBJECTIVE：To compare the change of related cervical biomechanical properties between DCI non-fusion and anterior decompression and fusion.METHODS：A total of 6 adult human fresh cervical spinal specimens（C2-7） were randomly divided into A,B,C groups.Following intact specimens analysis,specimens in groups A,B,C were sequentially reconstructed at C5-6 segment with DCI,Cage and integrated anterior cervical plate cage benezech（PCB） implant.The range of movement（ROM） of the upper and lower cervical segments of C5-6 in 3 groups before and after surgery in biomechanical testing machine for 4 different physiological conditions and impose 2.0 N？m pure moment of couple was measured.RESULTS AND CONCLUSION：After 3 kinds of fixation,the ROM of the upper and lower cervical segments of C5-6 increased more or less than the ROM of the intact specimens and showed better stability.And the ROM of cervical spine after fixation of DCI was similar to that of intact condition.There were no statistical significance between the ROM of the upper and lower cervical segments of C5-6 after 3 kinds of fixation（P 0.05）.There was no significant influence for the ROM of the upper and lower cervical segments.To some extent,the DCI diminished the axial stress and maintained the ROM of the cervical spine effectively.