Vagdargi Prasad, Sheth Niral, Sisniega Alejandro, Uneri Ali, De Silva Tharindu, Osgood Greg M, Siewerdsen Jeffrey H
Johns Hopkins University, Department of Computer Science, Baltimore, Maryland, United States.
Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland, United States.
J Med Imaging (Bellingham). 2021 Jan;8(1):015002. doi: 10.1117/1.JMI.8.1.015002. Epub 2021 Feb 12.
Percutaneous fracture fixation is a challenging procedure that requires accurate interpretation of fluoroscopic images to insert guidewires through narrow bone corridors. We present a guidance system with a video camera mounted onboard the surgical drill to achieve real-time augmentation of the drill trajectory in fluoroscopy and/or CT. The camera was mounted on the drill and calibrated with respect to the drill axis. Markers identifiable in both video and fluoroscopy are placed about the surgical field and co-registered by feature correspondences. If available, a preoperative CT can also be co-registered by 3D-2D image registration. Real-time guidance is achieved by virtual overlay of the registered drill axis on fluoroscopy or in CT. Performance was evaluated in terms of target registration error (TRE), conformance within clinically relevant pelvic bone corridors, and runtime. Registration of the drill axis to fluoroscopy demonstrated median TRE of 0.9 mm and 2.0 deg when solved with two views (e.g., anteroposterior and lateral) and five markers visible in both video and fluoroscopy-more than sufficient to provide Kirschner wire (K-wire) conformance within common pelvic bone corridors. Registration accuracy was reduced when solved with a single fluoroscopic view ( and 2.7 deg) but was also sufficient for K-wire conformance within pelvic bone corridors. Registration was robust with as few as four markers visible within the field of view. Runtime of the initial implementation allowed fluoroscopy overlay and/or 3D CT navigation with freehand manipulation of the drill up to . A drill-mounted video guidance system was developed to assist with K-wire placement. Overall workflow is compatible with fluoroscopically guided orthopaedic trauma surgery and does not require markers to be placed in preoperative CT. The initial prototype demonstrates accuracy and runtime that could improve the accuracy of K-wire placement, motivating future work for translation to clinical studies.
经皮骨折固定是一项具有挑战性的手术，需要准确解读透视图像，以便通过狭窄的骨通道插入导丝。我们提出了一种引导系统，该系统在手术钻上安装了摄像机，以实现透视和/或CT中钻孔轨迹的实时增强。摄像机安装在钻头上，并相对于钻头轴线进行校准。在手术区域周围放置在视频和透视中均可识别的标记，并通过特征对应进行配准。如果有术前CT，也可以通过3D-2D图像配准进行配准。通过在透视或CT上虚拟叠加已配准的钻轴来实现实时引导。根据目标配准误差（TRE）、在临床相关骨盆骨通道内的符合度以及运行时间对性能进行了评估。当用两个视图（例如前后位和侧位）求解且在视频和透视中可见五个标记时，钻轴与透视的配准显示中位TRE为0.9毫米和2.0度，足以在常见骨盆骨通道内提供克氏针（K针）的符合度。当用单一透视视图求解时，配准精度降低（分别为 和2.7度），但对于骨盆骨通道内的K针符合度也足够。在视野内可见少至四个标记时配准也很稳健。初始实现的运行时间允许进行透视叠加和/或3D CT导航，对钻头进行徒手操作可达 。开发了一种安装在钻头上的视频引导系统，以辅助K针放置。总体工作流程与透视引导的骨科创伤手术兼容，并且不需要在术前CT中放置标记。初始原型展示了可提高K针放置准确性的精度和运行时间，为转化为临床研究的未来工作提供了动力。
