Henderson Jaimie M, Holloway Kathryn L, Gaede Steven E, Rosenow Joshua M
Center for Functional and Restorative Neuroscience, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
Comput Aided Surg. 2004;9(4):155-60. doi: 10.3109/10929080500050249.
Frameless image guided systems have traditionally been perceived as being less accurate than stereotactic frames, limiting their adoption for trajectory-based procedures such as deep brain stimulator placement which require submillimetric accuracy. However, some studies have suggested that high degrees of accuracy are attainable with optical localization systems. We evaluated the application accuracy of a skull-mounted trajectory guide coupled to an optical image-guided surgery system in a laboratory setting.
A plastic skull phantom was fitted with five fiducial markers rigidly attached via self-drilling bone screws. Varying MRI and CT imaging protocols were obtained at 25 different centers. A metal disc marked in 1-mm increments was placed at the expected target point. Following registration and alignment of the trajectory guide, radial and depth localization errors were measured. A total of 560 measurements were obtained and detailed statistical analyses were performed.
Mean localization error was 1.25 mm with a 95% confidence interval of 2.7 mm and a 99.9% confidence interval of 4.0 mm. These values were significantly lower than those published for the two most widely used frame systems (p<0.001).
Accuracy of image-guided localization using a rigid trajectory guide can meet or exceed that achievable with a stereotactic frame.
传统上，无框架图像引导系统被认为不如立体定向框架精确，这限制了它们在诸如深部脑刺激器植入等基于轨迹的手术中的应用，这类手术需要亚毫米级的精度。然而，一些研究表明，光学定位系统可实现高度精确性。我们在实验室环境中评估了与光学图像引导手术系统相结合的颅骨安装轨迹引导器的应用准确性。
一个塑料颅骨模型通过自钻骨螺钉牢固地安装了五个基准标记物。在25个不同的中心获取了不同的MRI和CT成像方案。在预期靶点放置一个以1毫米增量标记的金属圆盘。在轨迹引导器配准和对齐后，测量径向和深度定位误差。共获得560次测量结果，并进行了详细的统计分析。
平均定位误差为1.25毫米，95%置信区间为2.7毫米，99.9%置信区间为4.0毫米。这些值显著低于两种使用最广泛的框架系统公布的值（p<0.001）。
使用刚性轨迹引导器进行图像引导定位的准确性能够达到或超过立体定向框架所能实现的准确性。
