Grubb M R, Currier B L, Shih J S, Bonin V, Grabowski J J, Chao E Y
Department of Orthopedics, Mayo Clinic, Rochester, Minnesota, USA.
Spine (Phila Pa 1976). 1998 Apr 15;23(8):886-92. doi: 10.1097/00007632-199804150-00009.
An in vitro biomechanical study.
To simulate a severe compressive flexion injury for determination of the relative stability of different anterior instrumentation systems in a porcine model and to validate this model in human cadaveric specimens.
Anterior plate fixation is useful for high-grade mechanical insufficiency of the cervical spine and may prevent the need for a second procedure.
The cervical spines of 45 porcine and 12 cadaveric specimens were subjected to nondestructive flexion, lateral bending, and torsional testing on a modified universal testing machine. A corpectomy was performed with release of the posterior ligamentous structures. The specimens were stabilized with one of three anterior plate constructs. The nondestructive testing was repeated to evaluate structural stability (stiffness and neutral zone). Finally, destructive testing examined failure moment, energy to failure, and mechanism of failure.
The instrumented specimens had flexural and lateral bending and torsional stiffness values that were similar to or greater than those of their paired intact specimens. The cervical spine locking plate had a significantly higher flexural stiffness ratio (plated:intact), torsional stiffness ratio, lower flexural neutral zone ratio, higher failure moment, and higher energy to failure than did the Caspar plate.
The cervical spine locking plate is theoretically safer than the Caspar system because the posterior vertebral body cortex is not breached by the fixation screws, and the screws are less likely to back out anteriorly and irritate the esophagus. According to these results, the cervical spine locking plate system is biomechanically equivalent to and in some cases more stable than the Caspar system for fixation of a severe compressive flexion injury.
一项体外生物力学研究。
在猪模型中模拟严重压缩性屈曲损伤，以确定不同前路内固定系统的相对稳定性，并在人体尸体标本中验证该模型。
前路钢板固定对于颈椎的高度机械性功能不全很有用，并且可能避免二次手术的需要。
在改良的万能试验机上对45个猪标本和12个尸体标本的颈椎进行无损屈曲、侧弯和扭转测试。进行椎体次全切除并松解后韧带结构。标本用三种前路钢板结构之一进行固定。重复无损测试以评估结构稳定性（刚度和中性区）。最后，进行破坏性测试以检查破坏力矩、破坏能量和破坏机制。
植入内固定的标本的屈曲、侧弯和扭转刚度值与配对的完整标本相似或更高。颈椎锁定钢板的屈曲刚度比（植入：完整）、扭转刚度比显著更高，屈曲中性区比更低，破坏力矩更高，破坏能量更高，优于Caspar钢板。
颈椎锁定钢板在理论上比Caspar系统更安全，因为固定螺钉不会穿透椎体后皮质，并且螺钉向前退出并刺激食管的可能性较小。根据这些结果，对于严重压缩性屈曲损伤的固定，颈椎锁定钢板系统在生物力学上等同于Caspar系统，并且在某些情况下更稳定。
