Magneto-Acoustic Hybrid Drive Architecture for High-Velocity, Sub-40°C Neurosurgical Microdrillers

Current local delivery systems (LDS) for minimally invasive neurosurgery utilizing magnetic microdrillers face a fundamental velocity-thermal constraint. While low-frequency actuation avoids tissue damage, it fails to achieve clinically viable rapid deployment. Attempting to scale translational velocities to >500 µm/s in dense tissue phantoms induces severe Joule heating, exceeding the 40°C human tissue necrosis threshold. In this paper, we introduce a novel Magneto-Acoustic Hybrid Drive architecture. Utilizing bare-metal, fully coupled multiphysics simulations (ElmerFEM), we computationally demonstrate a framework that decouples high-speed mechanical actuation from thermal dissipation. By pairing a 10:90 magnetic duty cycle with continuous Focused Ultrasound (FUS) for localized shear-thinning and acoustic streaming, we transiently pulse the active core while actively clamping the maximum system temperature to 38.6°C. This architecture maintains high average velocities in a 0.6% agarose phantom while reducing the cumulative thermal dose (CEM43) to functionally zero.