Ching R P, Watson N A, Carter J W, Tencer A F
Harborview Biomechanics Laboratory, Department of Orthopaedics, University of Washington, Seattle, USA.
Spine (Phila Pa 1976). 1997 Aug 1;22(15):1710-5. doi: 10.1097/00007632-199708010-00005.
The canal space of burst-fractured, human cervical spine specimens was monitored to determine the extent to which spinal position affected post-injury occlusion.
To test the null hypothesis that there is no difference in spinal canal occlusion as a function of spinal positioning for a burst-fractured cervical spine model.
Although previous studies have documented the effect of spinal positioning on canal geometry in intact cadaver spines, to the authors' knowledge, none has examined this relationship specifically in a burst fracture model.
Eight human cervical spine specimens (levels C1 to T3) were fractured by axial impact, and the resulting burst injuries were documented using post-injury radiographs and computed tomography scans. Canal occlusion was measured using a custom transducer in which water was circulated through a section of flexible tygon tubing that was passed through the spinal canal. Any impingement on the tubing produced a rise in fluid pressure that was monitored with a pressure transducer. Each spine was positioned in flexion, extension, lateral (and off-axis) bending, axial rotation, traction, and compression, while canal occlusion and angular position were monitored. Occlusion values for each position were compared with measurements taken with the spine in neutral position.
Compared with neutral position, compression, extension, and extension combined with lateral bending significantly increased canal occlusion, whereas flexion decreased the extent of occlusion. In extension, the observed mechanism of occlusion was ligamentum flavum bulge caused by ligament laxity resulting from reduced vertebral body height.
Increased compression of the spinal cord after injury may lead to more extensive neurologic loss. This study demonstrated that placing a burst-fractured cervical spine into either extension or compression significantly increased canal occlusion as compared with occlusion in a neutral position.
监测人颈椎爆裂骨折标本的椎管空间，以确定脊柱位置对损伤后椎管狭窄程度的影响。
检验零假设，即对于颈椎爆裂骨折模型，椎管狭窄程度与脊柱位置无关。
尽管先前的研究记录了脊柱位置对完整尸体脊柱椎管形态的影响，但据作者所知，尚无研究在爆裂骨折模型中专门研究这种关系。
对8个颈椎标本（C1至T3节段）进行轴向冲击致伤，使用伤后的X线片和计算机断层扫描记录所造成的爆裂损伤。使用定制的传感器测量椎管狭窄程度，其中水通过一段穿过椎管的柔性泰贡管循环。对管道的任何挤压都会导致流体压力升高，通过压力传感器进行监测。每个脊柱分别处于前屈、后伸、侧方（和偏离轴）弯曲、轴向旋转、牵引和压缩状态，同时监测椎管狭窄程度和角度位置。将每个位置的狭窄程度值与脊柱处于中立位时的测量值进行比较。
与中立位相比，压缩、后伸以及后伸联合侧方弯曲显著增加了椎管狭窄程度，而前屈则降低了狭窄程度。在后伸位，观察到的狭窄机制是由于椎体高度降低导致韧带松弛引起的黄韧带膨出。
损伤后脊髓受压增加可能导致更广泛的神经功能丧失。本研究表明，与中立位相比，将颈椎爆裂骨折置于后伸或压缩位会显著增加椎管狭窄程度。
