Windolf Markus, Richards Robert Geoff
AO Research Institute Davos, Concept Development Focus Area, Clavadelerstrasse 8, Davos 7270, Switzerland.
AO Research Institute Davos, Davos 7270, Switzerland.
J Med Device. 2021 Jun 1;15(2):025002. doi: 10.1115/1.4049979. Epub 2021 Mar 23.
Implant placement plays a key role in trauma and orthopedics. In this paper, a generic technological concept for implant positioning assistance is outlined. The system utilizes conventional radiographic devices for imaging and tracking and embeds into surgical workflows without the need for complex navigation equipment. It is based on feature extraction from cylindrical hole-projections in X-ray images for determining spatial alignment of implant and anatomy. Basic performance of a prototype system was experimentally verified in terms of tracking accuracy and robustness under varying conditions. In a second step, the system was developed into a set of application modules, each serving a pressing clinical need: Plating of the proximal humerus, cephalic nail and dynamic hip-screw placement, general anatomic plating, distal nail interlocking with adjustment of femoral anteversion and corrective osteotomies. Module prototypes were tested according to their degree of maturity from feasibility assessment in wet-labs to clinical handling tests. Orientation tracking of reference objects yielded an accuracy and precision of 0.1±0.71 deg (mean±standard deviation) with a maximum error of 4.68 deg at unfavorable conditions. This base-performance translated, e.g., into a precision of ±1.2 mm (standard deviation) screw-tip to joint distance at proximal humerus plating, or into a precision of lag screw positioning in the femoral head of ±0.6 mm in craniocaudal and ±1.6 mm in anterioposterior direction. The concept revealed strong potential to improve surgical outcomes in a broad range of orthopedic applications due to its generic and simplistic nature. Comprehensive validation activities must follow for clinical introduction.
植入物放置在创伤和骨科领域起着关键作用。本文概述了一种用于植入物定位辅助的通用技术概念。该系统利用传统的放射成像设备进行成像和跟踪，并嵌入到手术流程中，无需复杂的导航设备。它基于从X射线图像中的圆柱形孔投影中提取特征，以确定植入物与解剖结构的空间对齐。在不同条件下，对原型系统的基本性能进行了跟踪精度和鲁棒性方面的实验验证。第二步，该系统被开发成一组应用模块，每个模块都满足紧迫的临床需求：肱骨近端接骨板、头钉和动力髋螺钉置入、一般解剖接骨板、股骨远端交锁钉并调整股骨前倾角以及矫正截骨术。根据其成熟程度，对模块原型进行了测试，从湿实验室的可行性评估到临床操作测试。参考物体的方向跟踪精度和精密度为0.1±0.71°（平均值±标准差），在不利条件下最大误差为4.68°。例如，这种基本性能转化为肱骨近端接骨板时，螺钉尖端到关节距离的精度为±1.2毫米（标准差），或者转化为股骨头拉力螺钉定位在头尾方向的精度为±0.6毫米，前后方向的精度为±1.6毫米。由于其通用性和简单性，该概念在广泛的骨科应用中显示出改善手术效果的强大潜力。临床应用前必须进行全面的验证活动。
