Crawford N R, Dickman C A
Spinal Biomechanics Research Laboratory, Barrow Ncurological Institute, Phoenix, Arizona, USA.
Spine (Phila Pa 1976). 1997 Mar 1;22(5):559-63. doi: 10.1097/00007632-199703010-00020.
When studying three-dimensional motion of multiple-vertebra spine segments in vitro, it is often desirable to report the kinematics at the individual vertebral levels in terms of each level's local coordinates systems. A novel technique is described for constructing local vertebral coordinate axes using a standard digitizing probe.
To describe a technique that was developed to allow researchers to relate vertebral landmarks to optical markers and to set the local coordinate axes of several vertebrae accurately through a short, simple procedure performed only once at the beginning of a spine testing experiment.
Other researchers have used radiographs and careful marker placement for establishing the coordinate systems of vertebrae and the relationships of anatomic landmarks to optical markers. The authors found no publications giving details of how vertebral coordinate systems are established from anatomic landmarks.
A digitizing probe is used to identify vertebral landmarks and to relate these landmarks to optical markers attached to the vertebrae. An algorithm is described whereby vertebral coordinate axes are constructed from the landmarks.
The method described has been implemented successfully in a computerized in vitro spinal flexibility testing system that plots each individual motion segment's load-deformation curves in real time during experimentation. The proposed technique is less labor intensive and error prone than the earlier methods because landmarks are identified directly.
The described technique quickly, easily, and accurately relates anatomic landmarks to optical markers and constructs local coordinate axes, two steps that are necessary before monitoring the kinematics of individual motion segments during multilevel spine testing.
在体外研究多节段脊柱的三维运动时，通常希望根据每个节段的局部坐标系来报告各个椎体水平的运动学情况。本文描述了一种使用标准数字化探头构建局部椎体坐标轴的新技术。
描述一种开发的技术，使研究人员能够将椎体标志点与光学标记相关联，并通过在脊柱测试实验开始时仅执行一次的简短、简单程序准确设置多个椎体的局部坐标轴。
其他研究人员使用X线片和仔细放置标记来建立椎体的坐标系以及解剖标志点与光学标记的关系。作者未发现有出版物详细说明如何从解剖标志点建立椎体坐标系。
使用数字化探头识别椎体标志点，并将这些标志点与附着在椎体上的光学标记相关联。描述了一种算法，通过该算法从标志点构建椎体坐标轴。
所描述的方法已成功应用于计算机化的体外脊柱柔韧性测试系统，该系统在实验过程中实时绘制每个单独运动节段的载荷-变形曲线。与早期方法相比，该技术所需的劳动力更少且不易出错，因为标志点是直接识别的。
所描述的技术快速、轻松且准确地将解剖标志点与光学标记相关联并构建局部坐标轴，这是在多级脊柱测试期间监测单个运动节段运动学之前的两个必要步骤。
