Department of Mechanical Engineering, Queen's University, Kingston, ON, Canada.
Int J Comput Assist Radiol Surg. 2012 May;7(3):433-44. doi: 10.1007/s11548-011-0634-9. Epub 2011 Jun 25.
Percutaneous scaphoid fixation (PSF) is growing in popularity as a treatment option for non-displaced fractures. Success of this procedure demands high-precision screw placement, which can be difficult to achieve with standard 2D imaging. This study aimed to develop and test a system for computer-assisted navigation using volume slicing of 3D cone-beam computed tomography (CBCT).
The navigated technique involved a distinctive workflow in which a 3D CBCT imager was calibrated preoperatively, circumventing the need for intraoperative patient-based registration. Intraoperatively, a 3D CBCT image was acquired for both preoperative planning and direct navigation using volume-rendered slices. An in vitro study was conducted to compare the navigated approach to two conventional fluoroscopic methods for volar PSF. The surgical goal was to insert a guide wire to maximize both length and central placement.
There was no significant difference in the mean central placement of guide wire, although the variance in central placement was significantly lower using VS navigation (P < 0.01). The lengths of the drill paths were significantly longer for the VS-navigated group compared with one 2D group (P < 0.1). Each navigated trial required only one drilling attempt and resulted in less radiation exposure than conventional C-arm (P < 0.01).
Volume-sliced navigation achieved a more repeatable and reliable central pin placement, with fewer drilling attempts than conventional 2D techniques. Volume-sliced navigation had a higher number of drill paths within the optimal zone maximizing both length of the path and depth from the surface.
经皮舟骨固定术（PSF）作为非移位骨折的治疗选择越来越受欢迎。该手术的成功需要高精度的螺钉放置，而这在标准的 2D 成像中很难实现。本研究旨在开发和测试一种使用 3D 锥形束 CT（CBCT）容积切片的计算机辅助导航系统。
导航技术涉及一种独特的工作流程，其中 3D CBCT 成像仪在术前进行校准，避免了术中基于患者的注册需求。术中，使用容积再现切片采集 3D CBCT 图像，用于术前规划和直接导航。进行了一项体外研究，比较了导航方法与两种用于掌侧 PSF 的传统透视方法。手术目标是插入导丝，以最大限度地增加长度和中心位置。
导丝的中心位置平均值没有显著差异，尽管使用 VS 导航时中心位置的方差明显更低（P < 0.01）。与二维组相比，VS 导航组的钻孔路径长度明显更长（P < 0.1）。每个导航试验仅需要一次钻孔尝试，并且与传统 C 臂相比辐射暴露更少（P < 0.01）。
容积切片导航实现了更可重复和可靠的中央销钉放置，与传统的 2D 技术相比，钻孔尝试更少。容积切片导航具有更高数量的钻路径处于最佳区域，最大限度地增加了路径长度和从表面的深度。
