Responsive Focused Ultrasound for Facet Joint Back Pain: A Novel Noninvasive Therapeutic Approach

Focused ultrasound (FUS) is a noninvasive, image-guided therapeutic technology with growing potential for treating facet joint arthritis, a leading cause of chronic low back pain. Conventional treatments such as steroid injections, radiofrequency (RF) ablation, and cooled RF lesioning are invasive, depend on fluoroscopic guidance, and are limited by diagnostic uncertainty, procedural risks, and inconsistent long-term outcomes. This paper provides a comprehensive review of existing treatment modalities and introduces a novel, feedback-controlled FUS system designed for precise nerve ablation and neuromodulation. The system integrates maximum power point tracking (MPPT) to sustain ultrasonic resonance and utilizes acoustic feedback from cavitation-induced subharmonics to guide real-time energy delivery. Bench testing confirms robust frequency tracking, stable peak acoustic output, and reliable detection of cavitation onset. Literature comparisons show that FUS achieves comparable or superior pain relief (≥50% reduction in 80–85% of cases at 6 months) relative to RF neurotomy, while offering improved safety, patient tolerance, and procedural repeatability. By enabling accurate targeting and controlled energy delivery, FUS may reduce the risk of undertreatment often associated with suboptimal needle placement in RF procedures, positioning it as a precise and minimally invasive alternative for managing facet joint mediated back pain with the potential to enhance patient outcomes and reduce healthcare costs.