Mechanism of cervical spinal cord injury during bilateral facet dislocation
Mechanism of cervical spinal cord injury during bilateral facet dislocation
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DOI：
10.1097/brs.0b013e3181573b67
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发表时间：
2007-10-15
期刊：
影响因子：
3
通讯作者：
Panjabi, Manohar M.
中科院分区：
文献类型：
--
作者：
Ivancic, Paul C.;Pearson, Adam M.;Panjabi, Manohar M.
研究设计.一项体外生物力学研究。其目标是：在模拟双侧小关节脱位的颈椎功能性脊柱单元模型中，通过肌力复制，量化动态椎管夹径（CPD）狭窄，确定动态CPD狭窄峰值是否超过创伤后观察到的值，并评估动态脊髓压迫。以前的生物力学模型仅限于准静态加载或手动韧带横断。没有研究全面分析模拟脱位过程中的动态CPD狭窄。使用10个颈椎功能性脊柱单元（C3-C4：n = 4; C5-C6：n = 3; C7-T1：n = 3）模拟双侧小关节脱位，通过下椎体正面撞击进行肌力复制。光学记录的运动学数据的刚体变换用于计算在中性姿势（脱位前），在动态冲击（峰值脱位期间），和冲击后（屈曲旋转= 0）的CPD。动态冲击峰值和冲击后CPD狭窄进行统计学比较。平均峰值动态冲击CPD变窄显著超过（P < 0.05）后的冲击变窄，并发生在71.0 ms后的冲击。最大动态冲击狭窄发生在C3-C4，为7.2 mm，其次是C5-C6，为6.4 mm，C7-T1为5.1 mm，平均发生时间在C7-T1为71.0 ms和C5-C6为97.0 ms之间。外推目前的结果表明，动态脊髓压迫的88%，在狭窄的椎管和35%的椎管直径正常。这些结果与临床上观察到的双侧小关节脱位导致的神经系统损伤严重程度的广泛范围一致。
Study Design. An in vitro biomechanical study.Objectives. The objectives were to: quantify dynamic canal pinch diameter (CPD) narrowing during simulated bilateral facet dislocation of a cervical functional spinal unit model with muscle force replication, determine if peak dynamic CPD narrowing exceeded that observed post-trauma, and evaluate dynamic cord compression.Summary of Background Data. Previous biomechanical models are limited to quasi-static loading or manual ligament transection. No studies have comprehensively analyzed dynamic CPD narrowing during simulated dislocation.Methods. Bilateral facet dislocation was simulated using 10 cervical functional spinal units (C3-C4: n = 4; C5-C6: n = 3; C7-T1: n = 3) with muscle force replication by frontal impact of the lower vertebra. Rigid body transformation of kinematic data recorded optically was used to compute the CPD in neutral posture (before dislocation), during dynamic impact (peak during dislocation), and post-impact (flexion rotation = 0). Peak dynamic impact and post-impact CPD narrowing were statistically compared.Results. Average peak dynamic impact CPD narrowing significantly exceeded (P < 0.05) post-impact narrowing and occurred as early as 71.0 ms following impact. The greatest dynamic impact narrowing of 7.2 mm was observed at C3-C4, followed by 6.4 mm at C5-C6, and 5.1 mm at C7-T1, with average occurrence times ranging between 71.0 ms at C7-T1 and 97.0 ms at C5-C6.Conclusion. Extrapolation of the present results indicated dynamic spinal cord compression of up to 88% in those with stenotic canals and 35% in those with normal canal diameters. These results are consistent with the wide range of neurologic injury severity observed clinically due to bilateral facet dislocation.