Safe Flexible Intracerebral Navigation with Steerable Needles

描述（由申请人提供）：在肿瘤手术和脑深部电刺激（DBS）等脑介入治疗中，针放置的准确性至关重要，需要进行改进以提高治疗效果。 为了满足这一需求，我们开发了一种计算机控制的系统，该系统设计用于引导柔性针通过脑组织，具有比例控制的转向角度，使用在插入期间以“占空比”方式缓慢旋转针的优雅简单的技术。 该系统可用于到达大脑深处的目标，并可以在需要时绕道，以避免损伤敏感区域。 该系统的初步测试已在体外明胶基质和人尸体中进行。 迄今为止，对这项技术进行的测试仅侧重于达到特定目标的功效。 仍然存在几个未满足的需求，特别是开发用于在体内跟踪柔性探针的尖端的装置。 然而，在研究这些问题之前，需要在几个领域进行研究，以确保该技术的安全性。 本提案的具体目标如下：1. 调整头端几何形状和速度包络，以确保在脑实质中的安全性。 这将需要对针尖几何形状和针旋转过程进行有限元建模，以优化穿刺针的材料、斜角、边缘锐度、旋转速度和插入速度，从而避免损伤组织。 工作结果将在新鲜动物脑组织中进行体外验证，然后进行体内验证。 2. 调整头端几何形状和速度包络，以确保与血管接触的安全性。 该目的将涉及在猪模型中进行体内测试，并与标准直边活检针进行比较，以确认针的几何形状、旋转速度和穿刺针的插入速度，避免在插入过程中接触血管。 目标是将通过CT检测到的出血量限制在目前临床直探头脑针设计所显示的出血量。 3. 优化设计和速度包络，以避免沿着弯曲针轨迹长度的组织损伤。 与直探针不同，柔性针的插入当然会沿着针路径的外曲率施加一定量的应力。因此，除了上述专门处理针尖的工作之外，还需要对柔性针和组织之间的全部沿着轴的相互作用进行建模，优化针规格和速度包络的设计以避免沿着轨迹的组织损伤。 这项工作还将用于防止当轴旋转时柔性针的尖端的任何“旋转”或“鞭打”运动的可能性。 这项工作将在体外动物组织中进行验证，然后在体内猪模型中进行验证。 这些目标预期会使针尖看起来不像斜面针尖，而更像圆形针尖，圆形针尖的高点偏离中心。 公共卫生相关性：这项研究涉及开发改进的技术，以达到大脑深处的治疗部位，同时对大脑周围健康部位造成最小的干扰。 它有可能改善癌症、帕金森病和其他疾病的治疗效果。

DESCRIPTION (provided by applicant): Accuracy of needle placement is a matter of fundamental importance in brain interventions such as tumor surgery and deep brain stimulation (DBS), and there is a need for improvements in order to increase efficacy of treatment. In response to this need, we have developed a computer-controlled system designed to steer a flexible needle through brain tissue, with proportional control of steering angle, using an elegantly simple technique of slowly rotating the needle in a "duty-cycled" fashion during insertion. The system can be used to reach targets deep in the brain, and can detour when needed in order to avoid damaging sensitive areas. Preliminary testing of the system has been performed in vitro in a gelatin substrate and in human cadavers. The testing that has been performed to date on this technology has focused solely on efficacy in reaching a particular target. There remain several unanswered needs, especially the development of means for tracking the tip of the flexible probe in vivo. However, before progressing to these questions, research is needed in several areas in order to ensure the safety of the technique. The specific aims of this proposal are as follows: 1. To adapt the tip geometry and the velocity envelope for safety in brain parenchyma. This will require finite element modeling of the needle tip geometry and the process of needle rotation in order to optimize the material, bevel angle, edge sharpness, rotation speed, and insertion speed of the probe in order to avoid damage to tissue. Results of the work will be validated in fresh animal brain tissue in vitro and then in vivo. 2. To adapt the tip geometry and the velocity envelope for safety in contact with blood vessels. This aim will involve testing in vivo in a porcine model, with comparisons to standard straight-sided biopsy needles, in order to validate the needle geometry, rotation speed, and insertion speed of the probe, to avoid damage to blood vessels that are contacted during insertion. The goal will be to limit the amount of bleeding detected via CT to that exhibited by present clinical straight-probe brain needle designs. 3. To optimize the design and the velocity envelope to avoid tissue damage along the length of the curved needle trajectory. Unlike a straight probe, insertion of a flexible needle of course places a certain amount of stress along the outer curvature of the needle path. Therefore, in addition to the above work dealing specifically with the needle tip, it will be necessary to model the interaction between the flexible needle and the tissue all along the shaft, optimizing the design of the needle gauge and the velocity envelope to avoid tissue damage along the trajectory. This work will also serve to prevent the possibility of any "whirling" or "whipping" motion of the tip of the flexible needle as the shaft is rotated. This work will be validated in animal tissue in vitro and then in a porcine model in vivo. These aims are expected to result in a needle tip that looks less like a bevel-tipped needle and more like a round-tipped needle with the high point of the round tip shifted off-center. PUBLIC HEALTH RELEVANCE: This research involves the development of improved techniques for reaching treatment sites deep in the brain, while causing minimal disturbance to surrounding healthy parts of the brain. It has the potential to improve treatment outcomes for cancer, Parkinson's disease, and other disorders.