Nightingale Roger W, Carol Chancey V, Ottaviano Danielle, Luck Jason F, Tran Laura, Prange Michael, Myers Barry S
Duke University, Department of Biomedical Engineering, Division of Orthopaedic Surgery, Durham, NC 27708-0281, USA.
J Biomech. 2007;40(3):535-42. doi: 10.1016/j.jbiomech.2006.02.015. Epub 2006 Apr 18.
New vehicle safety standards are designed to limit the amount of neck tension and extension seen by out-of-position motor vehicle occupants during airbag deployments. The criteria used to assess airbag injury risk are currently based on volunteer data and animal studies due to a lack of bending tolerance data for the adult cervical spine. This study provides quantitative data on the flexion-extension bending properties and strength on the male cervical spine, and tests the hypothesis that the male is stronger than the female in pure bending. An additional objective is to determine if there are significant differences in stiffness and strength between the male upper and lower cervical spine. Pure-moment flexibility and failure testing was conducted on 41 male spinal segments (O-C2, C4-C5, C6-C7) in a pure-moment test frame and the results were compared with a previous study of females. Failures were conducted at approximately 90 N-m/s. In extension, the male upper cervical spine (O-C2) fails at a moment of 49.5 (s.d. 17.6)N-m and at an angle of 42.4 degrees (s.d. 8.0 degrees). In flexion, the mean moment at failure is 39.0 (s.d. 6.3 degrees) N-m and an angle of 58.7 degrees (s.d. 5.1 degrees). The difference in strength between flexion and extension is not statistically significant. The difference in the angles is statistically significant. The upper cervical spine was significantly stronger than the lower cervical spine in both flexion and extension. The male upper cervical spine was significantly stiffer than the female and significantly stronger than the female in flexion. Odontoid fractures were the most common injury produced in extension, suggesting a tensile mechanism due to tensile loads in the odontoid ligamentous complex.
新的车辆安全标准旨在限制在安全气囊展开时，未正确就座的机动车驾乘人员颈部所承受的张力和伸展程度。由于缺乏成人颈椎的弯曲耐受性数据，目前用于评估安全气囊伤害风险的标准是基于志愿者数据和动物研究得出的。本研究提供了关于男性颈椎屈伸弯曲特性和强度的定量数据，并检验了男性在纯弯曲方面比女性更强的假设。另一个目标是确定男性颈椎上、下部分在刚度和强度上是否存在显著差异。在纯力矩测试框架中对41个男性脊柱节段（枕骨 - C2、C4 - C5、C6 - C7）进行了纯力矩柔韧性和失效测试，并将结果与之前对女性的研究进行了比较。失效测试以约90N - m/s的速度进行。在伸展时，男性上颈椎（枕骨 - C2）在力矩为49.5（标准差17.6）N - m、角度为42.4度（标准差8.0度）时失效。在屈曲时，失效时的平均力矩为39.0（标准差6.3度）N - m，角度为58.7度（标准差5.1度）。屈曲和伸展之间的强度差异无统计学意义。角度差异有统计学意义。上颈椎在屈曲和伸展时均明显比下颈椎更强。男性上颈椎在屈曲时明显比女性更硬且更强。齿突骨折是伸展时最常见的损伤，提示齿突韧带复合体中由于拉伸载荷导致的拉伸机制。
