Bergmeier Jan, Fitzpatrick J Michael, Daentzer Dorothea, Majdani Omid, Ortmaier Tobias, Kahrs Lüder A
Institute of Mechatronic Systems, Leibniz Universität Hannover, Hannover, Germany.
Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA.
Int J Comput Assist Radiol Surg. 2017 Aug;12(8):1425-1437. doi: 10.1007/s11548-017-1594-5. Epub 2017 May 6.
Mastoid cells as well as trabecula provide unique bone structures, which can serve as natural landmarks for registration. Preoperative imaging enables sufficient acquisition of these structures, but registration requires an intraoperative counterpart. Since versatile surgical interventions involve drilling into mastoid cells and trabecula, we propose a registration method based on endoscopy inside of these drill holes.
Recording of the surface of the inner drill hole yields bone-air patterns that provide intraoperative registration features. In this contribution, we discuss an approach that unrolls the drill hole surface into a two-dimensional image. Intraoperative endoscopic recordings are compared to simulated endoscopic views, which originate from preoperative data like computed tomography. Each simulated view corresponds to a different drill pose. The whole registration procedure and workflow is demonstrated, using high-resolution image data to simulate both preoperative and endoscopic image data.
As the driving application is minimally invasive cochlear implantation, in which targets are close to the axis of the drill hole, Target Registration Error (TRE) was measured at points near the axis. TRE at increasing depths along the drill trajectory reveals increasing registration accuracy as more bone-air patterns become available as landmarks with the highest accuracy obtained at the center point. At the facial recess and the cochlea, TREs are ([Formula: see text]) mm and ([Formula: see text]) mm, respectively.
This contribution demonstrates a new method for registration via endoscopic acquisition of small features like trabecula or mastoid cells for image-guided procedures. It has the potential to revolutionize bone registration because it requires only a preoperative dataset and intraoperative endoscopic exploration. Endoscopic recordings of at least 20 mm length and isotropic voxel sizes of 0.2 mm or smaller of the preoperative image data are recommended.
乳突小房和骨小梁提供了独特的骨结构，可作为配准的自然标志物。术前成像能够充分获取这些结构，但配准需要术中对应的结构。由于多种外科手术操作涉及钻入乳突小房和骨小梁，我们提出一种基于这些钻孔内部内窥镜检查的配准方法。
记录钻孔内部表面可产生骨 - 气模式，这些模式提供术中配准特征。在本研究中，我们讨论一种将钻孔表面展开为二维图像的方法。将术中内窥镜记录与源自术前数据（如计算机断层扫描）的模拟内窥镜视图进行比较。每个模拟视图对应不同的钻孔姿态。使用高分辨率图像数据模拟术前和内窥镜图像数据，展示了整个配准过程和工作流程。
由于驱动应用是微创人工耳蜗植入，其中目标靠近钻孔轴线，在轴线附近的点测量目标配准误差（TRE）。沿钻孔轨迹深度增加时的TRE显示配准精度提高，因为更多的骨 - 气模式可作为地标，在中心点获得最高精度。在面神经隐窝和耳蜗处，TRE分别为（[公式：见原文]）毫米和（[公式：见原文]）毫米。
本研究展示了一种通过内窥镜获取骨小梁或乳突小房等小特征进行图像引导手术配准的新方法。它有可能彻底改变骨配准，因为它仅需要术前数据集和术中内窥镜探查。建议术前图像数据的内窥镜记录长度至少为20毫米，各向同性体素大小为0.2毫米或更小。
