Kaus M, Steinmeier R, Sporer T, Ganslandt O, Fahlbusch R
Neurochirurgische Klinik, University of Erlangen-Nümberg, Germany.
Neurosurgery. 1997 Dec;41(6):1431-6; discussion 1436-7. doi: 10.1097/00006123-199712000-00046.
This study was designed to determine and evaluate the different system-inherent sources of erroneous target localization of a light-emitting diode (LED)-based neuronavigation system (StealthStation, Stealth Technologies, Boulder, CO).
The localization accuracy was estimated by applying a high-precision mechanical micromanipulator to move and exactly locate (+/- 0.1 micron) the pointer at multiple positions in the physical three-dimensional space. The localization error was evaluated by calculating the spatial distance between the (known) LED positions and the LED coordinates measured by the neuronavigator. The results are based on a study of approximately 280,000 independent coordinate measurements.
The maximum localization error detected was 0.55 +/- 0.29 mm, with the z direction (distance to the camera array) being the most erroneous coordinate. Minimum localization error was found at a distance of 1400 mm from the central camera (optimal measurement position). Additional error due to 1) mechanical vibrations of the camera tripod (+/- 0.15 mm) and the reference frame (+/- 0.08 mm) and 2) extrapolation of the pointer tip position from the LED coordinates of at least +/- 0.12 mm were detected, leading to a total technical error of 0.55 +/- 0.64 mm.
Based on this technical accuracy analysis, a set of handling recommendations is proposed, leading to an improved localization accuracy. The localization error could be reduced by 0.3 +/- 0.15 mm by correct camera positioning (1400 mm distance) plus 0.15 mm by vibration-eliminating fixation of the camera. Correct handling of the probe during the operation may improve the accuracy by up to 0.1 mm.
本研究旨在确定并评估基于发光二极管（LED）的神经导航系统（StealthStation，Stealth Technologies，博尔德，科罗拉多州）中不同系统固有误差导致目标定位错误的来源。
通过应用高精度机械微操纵器在物理三维空间中的多个位置移动并精确放置（±0.1微米）指针来估计定位精度。通过计算（已知的）LED位置与神经导航仪测量的LED坐标之间的空间距离来评估定位误差。结果基于对约280,000次独立坐标测量的研究。
检测到的最大定位误差为0.55±0.29毫米，其中z方向（到相机阵列的距离）是误差最大的坐标。在距中央相机1400毫米处（最佳测量位置）发现最小定位误差。检测到由于1）相机三脚架（±0.15毫米）和参考框架（±0.08毫米）的机械振动以及2）从LED坐标推断指针尖端位置至少±0.12毫米而产生的额外误差，导致总技术误差为0.55±0.64毫米。
基于此技术精度分析，提出了一组操作建议，以提高定位精度。通过正确的相机定位（1400毫米距离）可将定位误差减少0.3±0.15毫米，通过消除相机振动固定可减少0.15毫米。手术过程中正确操作探头可将精度提高多达0.1毫米。
