Configuration optimization and experimental accuracy evaluation of a bone-attached, parallel robot for skull surgery
Configuration optimization and experimental accuracy evaluation of a bone-attached, parallel robot for skull surgery
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DOI：
10.1007/s11548-015-1300-4
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发表时间：
2016-03-01
影响因子：
3
通讯作者：
Ortmaier, Tobias
中科院分区：
文献类型：
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作者：
Kobler, Jan-Philipp;Nuelle, Kathrin;Ortmaier, Tobias
目的 微创人工耳蜗植入是一种新颖的手术技术，需要高度精确地引导钻孔工具沿着从乳突表面到耳蜗基底转的轨迹。作者提出了一种被动的、可重构的并行机器人，它可以直接连接到植入患者头骨中的骨锚，从而避免了手术跟踪系统的需要。在临床试验之前，需要针对患者具体优化机构配置的准确性和稳定性的方法。此外，可达到的精度必须通过实验来确定。方法考虑到先前研究中确定的所有相关误差源，建立了所提出机制的综合误差模型。从模型中得出了两个优化标准，以利用被动机器人的给定任务冗余性和可重构性。首先借助蒙特卡罗模拟方法估计优化后的机器人配置可达到的精度，最后使用合成颞骨样本在钻孔实验中进行评估。结果实验结果表明，骨附着机构在实际条件下表现出平均瞄准精度为 (0.36 +/- 0.12) mm。观察到系统的瞄准误差，这表明准确识别被动机器人的运动学参数可以进一步减少与计划钻孔轨迹的偏差。结论该机构的准确性表明其适用于微创人工耳蜗植入。未来的工作将集中于颞骨标本的进一步评估实验。
Purpose Minimally invasive cochlear implantation is a novel surgical technique which requires highly accurate guidance of a drilling tool along a trajectory from the mastoid surface toward the basal turn of the cochlea. The authors propose a passive, reconfigurable, parallel robot which can be directly attached to bone anchors implanted in a patient's skull, avoiding the need for surgical tracking systems. Prior to clinical trials, methods are necessary to patient specifically optimize the configuration of the mechanism with respect to accuracy and stability. Furthermore, the achievable accuracy has to be determined experimentally.Methods A comprehensive error model of the proposed mechanism is established, taking into account all relevant error sources identified in previous studies. Two optimization criteria to exploit the given task redundancy and reconfigurability of the passive robot are derived from the model. The achievable accuracy of the optimized robot configurations is first estimated with the help of a Monte Carlo simulation approach and finally evaluated in drilling experiments using synthetic temporal bone specimen.Results Experimental results demonstrate that the bone-attached mechanism exhibits a mean targeting accuracy of (0.36 +/- 0.12) mm under realistic conditions. A systematic targeting error is observed, which indicates that accurate identification of the passive robot's kinematic parameters could further reduce deviations from planned drill trajectories.Conclusion The accuracy of the proposed mechanism demonstrates its suitability for minimally invasive cochlear implantation. Future work will focus on further evaluation experiments on temporal bone specimen.