A quasi-resonant system for high-frequency trans-spinal magnetic stimulation (HF-TSMS)

Objective: We designed, developed, and tested a novel non-invasive system for high-frequency (HF) trans-spinal magnetic stimulation (TSMS). Methods: The system is based on a quasi-resonant pulse width modulation (PWM) design with customizable parameters, coupled with a custom figure-8 coil optimized for selective stimulation of spinal fibers. A key innovation is sequence-controlled zero current switching (SCZCS), which minimizes switching losses. Results: Through quasi-resonance, a capacitor bank canceled the coil inductance, enabling the generation of 10 kA current pulses with input voltages over three times lower than traditional magnetic stimulation methods. Preliminary rodent experiments, including electrophysiological recordings from the common peroneal nerve studies, demonstrated that the system's pulses reached the spinal cord. The HF-TSMS system operated safely, delivering HF stimulation without significant coil heating during experimental sessions. Conclusion: The proposed HF-TSMS system generated HF current pulses at lower cost, with reduced switching losses and higher efficiency. Significance: This system has the potential for integration into clinical practice as a safe and non-invasive treatment option for chronic pain management.