Sheth Niral, Vagdargi Prasad, Sisniega Alejandro, Uneri Ali, Osgood Gregory, Siewerdsen Jeffrey H
Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland, United States.
Johns Hopkins University, Department of Computer Science, Baltimore, Maryland, United States.
J Med Imaging (Bellingham). 2022 Jul;9(4):045004. doi: 10.1117/1.JMI.9.4.045004. Epub 2022 Aug 26.
Internal fixation of pelvic fractures is a challenging task requiring the placement of instrumentation within complex three-dimensional bone corridors, typically guided by fluoroscopy. We report a system for two- and three-dimensional guidance using a drill-mounted video camera and fiducial markers with evaluation in first preclinical studies. The system uses a camera affixed to a surgical drill and multimodality (optical and radio-opaque) markers for real-time trajectory visualization in fluoroscopy and/or CT. Improvements to a previously reported prototype include hardware components (mount, camera, and fiducials) and software (including a system for detecting marker perturbation) to address practical requirements necessary for translation to clinical studies. Phantom and cadaver experiments were performed to quantify the accuracy of video-fluoroscopy and video-CT registration, the ability to detect marker perturbation, and the conformance in placing guidewires along realistic pelvic trajectories. The performance was evaluated in terms of geometric accuracy and conformance within bone corridors. The studies demonstrated successful guidewire delivery in a cadaver, with a median entry point error of 1.00 mm (1.56 mm IQR) and median angular error of 1.94 deg (1.23 deg IQR). Such accuracy was sufficient to guide K-wire placement through five of the six trajectories investigated with a strong level of conformance within bone corridors. The sixth case demonstrated a cortical breach due to extrema in the registration error. The system was able to detect marker perturbations and alert the user to potential registration issues. Feasible workflows were identified for orthopedic-trauma scenarios involving emergent cases (with no preoperative imaging) or cases with preoperative CT. A prototype system for guidewire placement was developed providing guidance that is potentially compatible with orthopedic-trauma workflow. First preclinical (cadaver) studies demonstrated accurate guidance of K-wire placement in pelvic bone corridors and the ability to automatically detect perturbations that degrade registration accuracy. The preclinical prototype demonstrated performance and utility supporting translation to clinical studies.
骨盆骨折的内固定是一项具有挑战性的任务，需要在复杂的三维骨通道内放置器械，通常借助荧光透视法进行引导。我们报告了一种使用安装在钻头上的摄像机和基准标记进行二维和三维引导的系统，并在首次临床前研究中进行了评估。该系统使用固定在手术钻头上的摄像机和多模态（光学和不透射线）标记，以便在荧光透视和/或CT中进行实时轨迹可视化。对先前报道的原型的改进包括硬件组件（支架、摄像机和基准标记）和软件（包括用于检测标记扰动的系统），以满足转化为临床研究所需的实际要求。进行了体模和尸体实验，以量化视频荧光透视和视频CT配准的准确性、检测标记扰动的能力以及沿实际骨盆轨迹放置导丝的一致性。根据骨通道内的几何准确性和一致性对性能进行了评估。研究表明，在尸体中成功进行了导丝置入，入口点误差中位数为1.00毫米（四分位距1.56毫米），角度误差中位数为1.94度（四分位距1.23度）。这样的准确性足以引导克氏针通过所研究的六条轨迹中的五条进行放置，并且在骨通道内具有较高的一致性。第六例由于配准误差过大导致皮质穿孔。该系统能够检测标记扰动并提醒用户注意潜在的配准问题。确定了适用于涉及急诊病例（无术前影像）或术前有CT的病例的骨科创伤场景的可行工作流程。开发了一种用于导丝置入的原型系统，提供了可能与骨科创伤工作流程兼容的引导。首次临床前（尸体）研究表明，在骨盆骨通道中克氏针置入的引导准确，并且能够自动检测降低配准准确性的扰动。临床前原型展示了支持转化为临床研究的性能和实用性。
