Novel, Flexible, and Ultrathin Pressure Feedback Sensor for Miniaturized Intraventricular Neurosurgery Robotic Tools

Remote-controlled minimally invasive neuroendoscopic robotic surgical tools can be miniaturized to a size of less than 2 mm while maintaining their dexterity and force required to perform operations in brain without an open-skull surgery. However, these platforms lack haptic information to be received by the surgeons, leading to loss of control over tissue and causing unexpected slippage and trauma. This study presents the design of a small and highly sensitive material-based sensor being integrated to the tool shaft, known as the concentric tube manipulators, to achieve static and quasi-static force sensing and feedback. Through a nine-element design and contact mechanics modeling, the sensor system can generate real-time polar visual pressure profile displays. Optimizations are performed on the subcomponents of the sensor design including microstructures and electrodes to improve detection threshold with reduced hysteresis. The finalized design can sense a force from as low as 14.8 +/- 1.22 mN to 1 N with excellent proportionality between the acquired signal and force applied while retaining its flexibility and sterilizability. The sensor will also enhance more intuitive force feedback for surgeons to use the dexterous neurosurgical tool, ensuring safety and quality of operations for minimally invasive surgeries for brain tumor and epilepsy practice.