Use of Heart Rate Variability and Photoplethysmograph-Derived Parameters as Assessment Signals of Radiofrequency Therapy Efficacy for Chronic Pain

Background: Radiofrequency therapy (RFT) generates molecular motion and produces heat and electromagnetic effects on tissues, which attenuate pain sensation and thereby relieve pain. This study was to observe the altering trend of physiological parameters after RFT for chronic cervical or lumbar pain. Methods: This study recruited 66 patients with chronic cervical or lumbar pain and recorded their physiological parameters before and after RFT using heart rate variability (HRV) and photoplethysmography (PPG) to explore the feasibility of RFT efficacy assessment. Results: The patients' visual analog scale scores significantly decreased after RFT and the HRV parameters that represented parasympathetic activity significantly changed (HR decreased, and R-R interval and low- and high-frequency power increased significantly). Meanwhile, the PPG parameters that represented sympathetic activity also increased (PPG amplitude and autonomic nervous system state significantly decreased). Conclusions: This study showed significant efficacy of RFT in patients with chronic cervical or lumbar pain. The changes of HRV and PPG parameters may explain part of the mechanisms of RFT.