Spinal fixation procedures are currently limited by the rigidity of the existing instruments and pedicle screws leading to fixation failures and rigid pedicle screw pull out. Leveraging our recently developed Concentric Tube Steerable Drilling Robot (CT-SDR) in integration with a robotic manipulator, to address the aforementioned issue, here we introduce the transformative concept of Spatial Spinal Fixation (SSF) using a unique Flexible Pedicle Screw (FPS). The proposed SSF procedure enables planar and out-of-plane placement of the FPS throughout the full volume of the vertebral body. In other words, not only does our fixation system provide the option of drilling in-plane and out-of-plane trajectories, it also enables implanting the FPS inside linear (represented by an I-shape) and/or non-linear (represented by J-shape) trajectories. To thoroughly evaluate the functionality of our proposed robotic system and the SSF procedure, we have performed various experiments by drilling different I-J and J-J drilling trajectory pairs into our custom-designed L3 vertebral phantoms and analyzed the accuracy of the procedure using various metrics.

翻译：当前脊柱固定手术受限于现有器械和椎弓根螺钉的刚性结构，易导致固定失效及刚性椎弓根螺钉脱出。为应对上述问题，本研究结合近期研发的同心管可操控钻孔机器人（CT-SDR）与机械臂系统，提出采用独特柔性椎弓根螺钉（FPS）的空间脊柱固定（SSF）变革性理念。所提出的SSF手术方案支持在椎体全空间范围内进行平面及离面FPS置入。换言之，本固定系统不仅提供平面与离面钻孔轨迹的选择，还能实现FPS在直线型（以I形表示）和/或曲线型（以J形表示）轨迹中的植入。为全面评估所提出的机器人系统及SSF手术方案的功能性，我们通过在定制设计的L3椎体仿体上钻削多组I-J与J-J钻孔轨迹对，并采用多种度量指标分析手术精度，开展了系列实验验证。