Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany.
Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany.
Spine J. 2018 Mar;18(3):515-524. doi: 10.1016/j.spinee.2017.10.065. Epub 2017 Oct 23.
The range of motion is a well-accepted parameter for the assessment and evaluation of cervical motion. However, more qualitative data of the kinematics of the cervical spine are needed for the development and success of cervical disc arthroplasty.
The aim of this study was to provide basic information about helical axes of human cervical spine under in vitro conditions. Furthermore, it should clarify whether the three-dimensional helical axes of cervical motion gained from in vitro experiments are in agreement with those gained from in vivo experiments, and therefore to prove its reliability.
STUDY DESIGN/SETTING: An in vitro test with pure moments and mono-segmental specimens was designed to investigate and compare the helical axes of the cervical spine.
Six human cadaveric specimens (three male and three female) with an average age of 47.5 years (range: 34-58 years) were carefully selected. Each specimen was divided into three motion segments: C2-C3, C4-C5, and C6-C7. We performed 3.5 full cycles of rotation about all axes, flexion-extension, lateral bending, and axial rotation, by applying pure moments of 1.5 Nm without any preload. Following the in vitro tests, the three-dimensional helical axes were calculated and projected into the x-ray images.
Rotation analysis of all three directions revealed similar results for all six specimens. All calculated helical axes were similar to the published in vivo data. Furthermore, the instantaneous centers of rotation were in agreement with in vivo data.
The data gained from this study verify cervical kinematics during in vitro testing using pure moments. It can be assumed that other soft tissue such as muscles are not necessarily needed to simulate cervical kinematics in vitro.
运动范围是评估颈椎运动的一个可接受的参数。然而，为了颈椎间盘置换术的发展和成功，需要更多颈椎运动运动学的定性数据。
本研究的目的是提供体外条件下人类颈椎螺旋轴的基本信息。此外，还应阐明从体外实验获得的颈椎运动三维螺旋轴是否与从体内实验获得的一致，从而证明其可靠性。
研究设计/设置：设计了一项体外试验，使用纯力矩和单节段标本，以研究和比较颈椎的螺旋轴。
精心挑选了 6 具平均年龄为 47.5 岁（范围：34-58 岁）的人体尸体标本（3 名男性和 3 名女性）。每个标本分为三个运动节段：C2-C3、C4-C5 和 C6-C7。我们在没有任何预载的情况下施加 1.5 Nm 的纯力矩，对所有轴进行了 3.5 个完整的旋转周期、屈伸、侧屈和轴向旋转。在体外试验之后，计算了三维螺旋轴并将其投影到 X 射线图像上。
所有三个方向的旋转分析都显示了所有 6 个标本的相似结果。所有计算出的螺旋轴都与已发表的体内数据相似。此外，瞬时旋转中心与体内数据一致。
本研究获得的数据验证了使用纯力矩进行体外测试时的颈椎运动学。可以假设，在体外模拟颈椎运动时，不需要其他软组织，如肌肉。
