Resumen

Objectives: This lecture aims to provide evidence-based guidance on return electrode positioning in monopolar radiofrequency (MRF) procedures. Attendees will learn how spatial positioning affects thermal diffusion, impedance dynamics, and treatment depth, and how to apply physical and mathematical models to optimize safety and clinical outcomes. Introduction: In monopolar radiofrequency treatments, the positioning of the return electrode is a critical yet often overlooked factor influencing impedance stability, thermal profile, and energy penetration. Despite its importance, standardized, accurate guidelines for optimal electrode placement remain absent. This study addresses this gap using theoretical modeling to inform practical recommendations. Materials / method: Triggered by a clinical case involving superficial burn injury, this study employed physical and mathematical models, including electric field simulation, impedance variation (IV), impedance variation rate (IVR), and energy penetration depth analysis. Various return electrode distances (0.15–0.7 m) were analyzed to evaluate their effect on energy dispersion and thermal safety. Results: The proximity of the return electrode (<0.2 m) amplified superficial heating and elevated the risk of thermal injury. Conversely, positioning beyond 0.5 m reduced treatment efficacy. An intermediate distance of approximately 0.45 m achieved optimal impedance control, uniform heat diffusion, and therapeutic depth without compromising safety. Conclusion: For commonly used systems such as Thermage FLX, return electrode placement at ~0.45 m from the target zone—typically on the patient’s back or abdomen—offers the best balance between efficacy and safety. As results depend on specific device parameters, clinicians must re-calculate placement strategies when using different RF platforms. Clinical validation studies are warranted.