A Wireless Power Transfer System for Leadless Endovascular Electrocorticography

Purpose :Wireless power transfer (WPT) for stent-based medical devices in the brain, such as endovascular electrocorticography (endoECoG) devices, faces challenges. Typical stent-based endoECoG consists of electrodes placed on a stent and connected with a set of long lead wires to a subcutaneous chest implant responsible for wireless energy harvesting and data telemetry. Eliminating the long lead wires is not a trivial or straightforward task, introducing a great set of challenges. This work demonstrates a feasible method to deliver power directly to a standard medical stent without modifying its structure, mechanically or electrically. Methods :The proposed system employs a subcutaneous relay that converts inductive coupling to capacitive coupling. This solution not only enhances power transfer efficiency while maintaining minimal invasiveness but also addresses the challenges of unstable contact impedance with capacitive coupling WPT. Experimental validation was performed using real skin, bone, and vessel tissues, and finite element simulations were conducted to confirm model accuracy. Results :Experiments demonstrated over 45 mW of power delivery without exceeding safety limits, sufficient for powering endoECoG devices and biosignal sensors. The system achieved 7.26\% DC-to-DC efficiency, the highest reported for stent-based implants without additional transceivers or specialized stent designs. Results closely matched simulations, confirming practical viability. Safety assessments, including specific absorption rate (SAR) analysis and temperature rise simulations, showed compliance with regulatory standards and minimal risk to surrounding tissues. Conclusion :This work demonstrates a reasonably efficient and safe power delivery to stent-based implants in the brain, considering the anatomical challenges regarding the surgical delivery, paving the way for fully wireless, minimally invasive neuroprosthetic devices. The external device does not require close skin contact, making it suitable for long-term applications and improving patient comfort. Future efforts will optimize system components and address manufacturing challenges to facilitate clinical translation.