Wolfla Christopher E, Salerno Simon A, Yoganandan Narayan, Pintar Frank A
Department of Neurosurgery, The Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Neurosurgery. 2007 Sep;61(3 Suppl):87-93; discussion 93. doi: 10.1227/01.neu.0000289720.04836.fd.
This study was designed to test the kinematic properties of three occiput-C2 instrumentation constructs with and without supplemental rigid C1 fixation. The results are compared with intact specimens and with constructs incorporating contemporary cabling techniques.
Five unembalmed human cadaver specimens underwent range of motion (ROM) testing in the intact condition, followed by destabilization with odontoid osteotomy. Destabilized specimens then underwent ROM testing with each of seven occipitocervical instrumentation constructs, all incorporating occipital screws: C1 and C2 sublaminar cables with cable connectors, C2 pars screws +/- C1 lateral mass screws, C2 lamina screws +/- C1 lateral mass screws, and C1-C2 transarticular screws +/- C1 lateral mass screws.
All seven constructs demonstrated significantly lower ROM in all loading modes than intact specimens (P < 0.05). With a single exception, the addition of C1 lateral mass screws to the screw-based constructs produced no significant change in ROM in any of the loading modes. Compared with intact specimens, constructs anchored by C1-C2 transarticular screws demonstrated the greatest decrease in ROM, and those anchored by sublaminar cables demonstrated the least decrease in ROM.
Any of the tested screw-based constructs are likely to provide adequate support for the patient with an unstable craniocervical junction. Therefore, the choice of construct should be based on anatomic considerations. The routine incorporation of C1 lateral mass screws into occipitocervical instrumentation constructs does not seem necessary.
本研究旨在测试三种枕骨 - C2固定器械结构在有和没有补充性C1刚性固定情况下的运动学特性。将结果与完整标本以及采用当代缆线技术的结构进行比较。
五具未防腐处理的人体尸体标本在完整状态下进行活动范围（ROM）测试，随后通过齿突截骨使其失稳。失稳后的标本接着使用七种枕颈固定器械结构中的每一种进行ROM测试，所有结构均包含枕骨螺钉：带缆线连接器的C1和C2椎板下缆线、C2椎弓根螺钉+/- C1侧块螺钉、C2椎板螺钉+/- C1侧块螺钉以及C1 - C2经关节螺钉+/- C1侧块螺钉。
所有七种结构在所有加载模式下的ROM均显著低于完整标本（P < 0.05）。除一个例外情况外，在基于螺钉的结构中添加C1侧块螺钉在任何加载模式下ROM均无显著变化。与完整标本相比，由C1 - C2经关节螺钉固定的结构ROM下降最大，而由椎板下缆线固定的结构ROM下降最小。
任何一种经测试的基于螺钉的结构都可能为不稳定的颅颈交界患者提供足够的支撑。因此，结构的选择应基于解剖学考虑。常规将C1侧块螺钉纳入枕颈固定器械结构似乎没有必要。
