Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA.
Spine (Phila Pa 1976). 2013 Jan 1;38(1):E1-12. doi: 10.1097/BRS.0b013e3182793873.
Biomechanical tensile testing of perinatal, neonatal, and pediatric cadaveric cervical spines to failure.
To assess the tensile failure properties of the cervical spine from birth to adulthood.
Pediatric cervical spine biomechanical studies have been few due to the limited availability of pediatric cadavers. Therefore, scaled data based on human adult and juvenile animal studies have been used to augment the limited pediatric cadaver data. Despite these efforts, substantial uncertainty remains in our understanding of pediatric cervical spine biomechanics.
A total of 24 cadaveric osteoligamentous head-neck complexes, 20 weeks gestation to 18 years, were sectioned into segments (occiput-C2 [O-C2], C4-C5, and C6-C7) and tested in tension to determine axial stiffness, displacement at failure, and load-to-failure.
Tensile stiffness-to-failure (N/mm) increased by age (O-C2: 23-fold, neonate: 22 ± 7, 18 yr: 504; C4-C5: 7-fold, neonate: 71 ± 14, 18 yr: 509; C6-C7: 7-fold, neonate: 64 ± 17, 18 yr: 456). Load-to-failure (N) increased by age (O-C2: 13-fold, neonate: 228 ± 40, 18 yr: 2888; C4-C5: 9-fold, neonate: 207 ± 63, 18 yr: 1831; C6-C7: 10-fold, neonate: 174 ± 41, 18 yr: 1720). Normalized displacement at failure (mm/mm) decreased by age (O-C2: 6-fold, neonate: 0.34 ± 0.076, 18 yr: 0.059; C4-C5: 3-fold, neonate: 0.092 ± 0.015, 18 yr: 0.035; C6-C7: 2-fold, neonate: 0.088 ± 0.019, 18 yr: 0.037).
Cervical spine tensile stiffness-to-failure and load-to-failure increased nonlinearly, whereas normalized displacement at failure decreased nonlinearly, from birth to adulthood. Pronounced ligamentous laxity observed at younger ages in the O-C2 segment quantitatively supports the prevalence of spinal cord injury without radiographic abnormality in the pediatric population. This study provides important and previously unavailable data for validating pediatric cervical spine models, for evaluating current scaling techniques and animal surrogate models, and for the development of more biofidelic pediatric crash test dummies.
对围产期、新生儿和儿科尸体颈椎进行生物力学拉伸测试直至失效。
评估从出生到成年颈椎的拉伸失效特性。
由于儿科尸体标本的有限可用性，儿科颈椎生物力学研究很少。因此，基于人类成人和幼年动物研究的比例数据已被用于补充有限的儿科尸体数据。尽管做出了这些努力，但我们对儿科颈椎生物力学的理解仍存在很大的不确定性。
总共 24 个胎龄 20 周至 18 岁的头-颈骨-韧带复合标本被分为节段（枕骨-颈 2 段 [O-C2]、C4-C5 段和 C6-C7 段）并进行拉伸测试，以确定轴向刚度、失效时的位移和失效时的载荷。
拉伸刚度-失效（N/mm）随年龄增长而增加（O-C2：23 倍，新生儿：22±7，18 岁：504；C4-C5：7 倍，新生儿：71±14，18 岁：509；C6-C7：7 倍，新生儿：64±17，18 岁：456）。失效时的载荷（N）随年龄增长而增加（O-C2：13 倍，新生儿：228±40，18 岁：2888；C4-C5：9 倍，新生儿：207±63，18 岁：1831；C6-C7：10 倍，新生儿：174±41，18 岁：1720）。失效时的归一化位移（mm/mm）随年龄增长而减少（O-C2：6 倍，新生儿：0.34±0.076，18 岁：0.059；C4-C5：3 倍，新生儿：0.092±0.015，18 岁：0.035；C6-C7：2 倍，新生儿：0.088±0.019，18 岁：0.037）。
从出生到成年，颈椎拉伸刚度-失效和失效载荷呈非线性增加，而失效时的归一化位移呈非线性减少。在 O-C2 节段，年轻患者中观察到的韧带明显松弛，定量支持了儿科人群中脊髓损伤无放射学异常的普遍存在。本研究为验证儿科颈椎模型、评估当前比例技术和动物替代模型以及开发更符合生物力学的儿科碰撞试验假人提供了重要且以前无法获得的数据。
