Holmes A, Han Z H, Dang G T, Chen Z Q, Wang Z G, Fang J
Mechanics Department, Peking University, Beijing, People's Republic of China.
Spine (Phila Pa 1976). 1996 Jun 1;21(11):1313-9. doi: 10.1097/00007632-199606010-00006.
Quasistatic flexion and extension loads were applied in vitro to lower cervical spines. The flexion-extension motion produced was checked for physiologic relevance.
To examine the changes in the volume of the cervical spinal canal in flexion-extension motion.
Many papers have been published concerning the cervical canal volume as inferred from standard lateral radiographs. This study compares the inferred (radiographic) volumes and their changes to the physical changes within the spinal canal.
The lower cervical spines (C2-C7) from 10 cadavers were subject to stepwise flexion and extension in a purpose-built rig. Before this testing, the spinal cord was removed from the canal space of each specimen and replaced by a thin latex tube stoppered and secured at the opening of the canal (at C2) so that the volume of liquid displaced from the tube could be measured. This was done at each loading stage by means of a graduated glass column, and a radiograph of the spine was also taken to allow angular and displacement readings to be taken from C2 to C7.
The average recorded change in volume of the spinal canal with flexion-extension motion was 1.9 ml, and showed a significant linear correlation with the dynamic canal width (r = 0.868, P < 0.05) and also with the total angle of flexion or extension (r = 0.979, P < 0.005). The volume of liquid displaced from the canal in lateral bending was much lower than that in flexion-extension motion, and only amounted to about 0.2 ml. The angular ranges of motion produced at each level were compared to previous results obtained in vivo, and no significant differences between the angular displacements found in vivo and in vitro under this experimental arrangement were seen.
The loading regime described in this study causes angular displacements similar to those in vivo, and on this basis is a physiologically relevant loading pattern. The change in the volume of the spinal canal between C2 and C7 shows linear relationships with the angle of flexion and the dynamic canal width.
对下颈椎进行体外准静态屈伸加载。检查所产生的屈伸运动是否具有生理相关性。
研究颈椎管在屈伸运动中容积的变化。
已有多篇关于从标准侧位X线片推断颈椎管容积的论文发表。本研究将推断的（X线片上的）容积及其变化与椎管内的实际变化进行比较。
从10具尸体上取下下颈椎（C2 - C7），在特制装置中进行逐步屈伸。在此测试之前，将脊髓从每个标本的椎管内取出，用一根细乳胶管代替，乳胶管在椎管开口处（C2处）堵塞并固定，以便测量从管中排出的液体体积。在每个加载阶段通过刻度玻璃柱进行此操作，同时还拍摄脊柱的X线片，以便获取从C2到C7的角度和位移读数。
屈伸运动时椎管容积的平均记录变化为1.9毫升，与动态椎管宽度呈显著线性相关（r = 0.868，P < 0.05），也与屈伸总角度呈显著线性相关（r = 0.979，P < 0.005）。侧弯时椎管内排出的液体体积远低于屈伸运动时，仅约为0.2毫升。将每个节段产生的运动角度范围与先前在体内获得的结果进行比较，在这种实验设置下，体内和体外发现的角度位移之间没有显著差异。
本研究中描述的加载方式产生的角度位移与体内相似，在此基础上是一种具有生理相关性的加载模式。C2和C7之间椎管容积的变化与屈伸角度和动态椎管宽度呈线性关系。
