Nuckley David J, Van Nausdle Joseph A, Eck Michael P, Ching Randal P
Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
Spine (Phila Pa 1976). 2007 Mar 15;32(6):E181-7. doi: 10.1097/01.brs.0000257527.22080.d7.
A factorial study design was used to examine the biomechanical and neuroprotective integrity of the cervical spine throughout maturation using a postmortem baboon model.
To investigate changes with spinal development that affect the neuroprotective ability of the cervical spine in compressive loading.
Child spinal cord injuries claim and debilitate thousands of children in the United States each year. Many of these injuries are diagnostically and mechanistically difficult to classify, treat, and prevent. Biomechanical studies on maturing spinal tissues have identified decreased stiffness and tolerance characteristics for children compared with adults. Unfortunately, while neurologic deficit typically dictates functional outcome, no previous studies have examined the neuroprotective role of the pediatric cervical spine.
Twenty-two postmortem baboon cervical spines across the developmental age spectrum were tested. Two functional spinal unit segments (Oc-C2, C3-C5, and C6-T1) were instrumented with transducers to measure dynamic changes in the spinal canal. These tissues were compressed to 70% strain dynamically, and the resultant mechanics and spinal canal occlusions were recorded.
Classic injury patterns were observed in all of the specimens tested. The compressive mechanics exhibited a significant age relationship (P < 0.0001). Furthermore, while the peak-percent spinal canal occlusion was not age dependent, the percent occlusion just before failure did demonstrate a significant decrease with advancing age (P = 0.0001).
The neuroprotective ability of the cervical spine preceding failure appears to be age dependent, where the young spine can produce greater spinal canal occlusions without failure than its adult counterpart. The overall percent of the spinal canal occluded during a compression injury was not age dependent; however, these data reveal the neuroprotective ability of the child spine to be more sensitive as an injury predictor than the biomechanical fracture data.
采用析因研究设计，利用死后狒狒模型研究颈椎在整个发育过程中的生物力学和神经保护完整性。
研究脊柱发育过程中的变化，这些变化会影响颈椎在压缩载荷下的神经保护能力。
在美国，儿童脊髓损伤每年导致数千名儿童受伤并致残。其中许多损伤在诊断和机制上难以分类、治疗和预防。对成熟脊柱组织的生物力学研究表明，与成年人相比，儿童的脊柱刚度和耐受性特征有所降低。不幸的是，虽然神经功能缺损通常决定功能预后，但此前尚无研究探讨小儿颈椎的神经保护作用。
对22个不同发育年龄阶段的死后狒狒颈椎进行测试。在两个功能性脊柱单元节段（枕骨 - C2、C3 - C5和C6 - T1）安装传感器，以测量椎管内的动态变化。对这些组织进行动态压缩至70%应变，并记录由此产生的力学变化和椎管闭塞情况。
在所有测试标本中均观察到典型的损伤模式。压缩力学表现出显著的年龄相关性（P < 0.0001）。此外，虽然椎管闭塞的峰值百分比与年龄无关，但在失效前的闭塞百分比确实随着年龄的增长而显著降低（P = 0.0001）。
颈椎在失效前的神经保护能力似乎与年龄有关，幼年脊柱在不发生失效的情况下能够产生比成年脊柱更大的椎管闭塞。压缩损伤期间椎管闭塞的总体百分比与年龄无关；然而，这些数据表明，作为损伤预测指标，儿童脊柱的神经保护能力比生物力学骨折数据更为敏感。
