Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, SAR China.
Spine (Phila Pa 1976). 2010 Feb 15;35(4):395-402. doi: 10.1097/BRS.0b013e3181c9fa35.
A biomechanical cadaveric and radiographic analyses.
To identify and elaborate on specific anatomic soft tissue structures that are injured during various stages of a distractive-extension (DE) injury of the lower cervical spine and their role in angulation and posterior translation.
Two DE stages (DES) of injury to the cervical spine have been described as follows: DES-1 and DES-2. However, the role of the soft tissue structures involved in such injuries has not been clearly defined. Furthermore, the importance of the facet capsules in DES injuries has not been well-addressed.
A total of 15 adult cadaveric motion segments of the lower cervical spine were isolated and tested. Motion segments were mounted, with the cervical spine in extension, such that a distractive load was applied through the cephalad body. Anatomic supporting structures were serially sectioned from anterior to posterior to simulate varying degrees of soft-tissue disruption as occurring with the DE mechanism. Specimens were loaded at each stage of injury and measurements of angulation and posterior translation were recorded from fluoroscopic images by 2 independent observers.
A strong correlation was noted between the 2 sets of independent measurements. A statistical significant difference was noted between the degree of soft-tissue injury to the change in angulation and posterior translation (P < 0.001). The mean change in angulation and posterior translation was significantly greatest following sectioning of the anterior aspect of the facet capsules and to a lesser extent following sectioning of the posterior longitudinal ligament (PLL) (P < 0.001). A greater mean percent change between sequential sectioning of soft tissue structures was largely associated with posterior translation rather than angulation.
Sequentially greater angulation and posterior translation was seen after serial sectioning of the anterior facet capsule and to a lesser degree the PLL. This suggests that there are in fact 2 main "tethers" to angulation and posterior translation in the DE injury model, with the anterior facet capsule being the major stabilizer and to a lesser degree the PLL. Thus, based on our findings, it would appear that an expansion of the DE injury classification may be warranted, based on angulation and posterior translation, and regarded as DES-1, DES-2A, DES-2B, and DES-3. Such categorization based on the degree of angulation and posterior translation may prove advantageous in designing appropriate treatment strategies to address DE injuries of the lower cervical spine; however, further studies are needed to validate the clinical applications of such categorization.
生物力学尸体和影像学分析。
确定并详细说明在下颈椎伸展性（DE）损伤的各个阶段受伤的特定解剖软组织结构及其在角度和后向平移中的作用。
已经描述了颈椎的两种 DE 损伤阶段（DES）如下：DES-1 和 DES-2。然而，涉及此类损伤的软组织结构的作用尚未明确界定。此外，关节囊在 DES 损伤中的重要性尚未得到很好的解决。
共分离和测试了 15 个成人下颈椎运动节段的尸体。将运动节段安装在伸展状态下，使颈椎通过头部体施加牵拉载荷。从前到后连续切割解剖支撑结构，以模拟与 DE 机制一起发生的不同程度的软组织破坏。在损伤的每个阶段对标本进行加载，并通过 2 位独立观察者从荧光透视图像记录角度和后向平移的测量值。
两组独立测量值之间存在很强的相关性。在软组织损伤程度与角度和后向平移变化之间观察到统计学显著差异（P <0.001）。在前关节囊的前侧和在较小程度上在后纵韧带（PLL）的后侧进行切割后，角度和后向平移的变化明显最大（P <0.001）。在连续切割软组织结构之间的平均百分比变化较大主要与后向平移有关，而不是角度。
在前关节囊和 PLL 进行连续切割后，角度和后向平移的角度更大。这表明，在 DE 损伤模型中，实际上有两个主要的“固定物”用于角度和后向平移，前关节囊是主要的稳定器，而 PLL 的程度较小。因此，根据我们的发现，似乎可能需要根据角度和后向平移来扩展 DE 损伤分类，并将其视为 DES-1、DES-2A、DES-2B 和 DES-3。基于角度和后向平移的这种分类可能有助于设计治疗下颈椎伸展性损伤的适当治疗策略；然而，需要进一步的研究来验证这种分类的临床应用。
