Prolonged-duration pulsed radiofrequency is associated with increased neuronal damage without further antiallodynic effects in neuropathic pain model rats

Abstract

Aim of investigationPulsed radiofrequency (PRF) is a safe and effective approach for treating neuropathic pain. However, the optimal treatment conditions and analgesic mechanisms of PRF remain unclear. The aim of our study was to assess the beneficial and adverse effects of prolonged-duration PRF and the analgesic mechanisms of PRF treatment with neuropathic pain rats.MethodsMale Sprague Dawley rats received L5 spinal nerve ligation (SNL) for developing neuropathic pain. Fourteen days after L5 SNL surgery, they were divided into three groups according to duration of PRF current for 6 minutes, 12 minutes, and none. PRF current was delivered via direct visualization adjacent to the L5 dorsal root ganglion (DRG). Pain behavior was evaluated every week after L5 SNL surgery, until day 28. Seven days after PRF treatment, L5 DRG tissue was harvested to detect levels of activating translation factor 3 (ATF3; a marker of neuronal damage) and hyperpolarization-activated cyclic nucleotide (HCN)-gated cation channels (key factors in neuropathic pain) using quantitative PCR.ResultsBefore PRF application, withdrawal thresholds were significantly lower than at baseline and did not differ significantly between the three groups. After PRF application, withdrawal thresholds in the PRF6 and PRF12 groups were significantly increased compared to those in the sham group. However, those in the PRF6 and PRF12 groups did not differ significantly. The expression level of ATF3 mRNA in the PRF12 group was significantly higher than that in the sham group (P<0.01), but the expression of HCN1 and HCN2 channels did not differ significantly between the three groups.ConclusionProlonged PRF exposure, from 6 to 12 minutes, was not only ineffective but also associated with increased neuronal damage. These findings do not support prolonged PRF exposure as a helpful treatment for neuropathic pain. In this study, the involvement of HCN channels in the antiallodynic effects of PRF was uncertain.

Evaluation of the efficacy of unipolar and bipolar spinal dorsal root ganglion radiofrequency thermocoagulation in the treatment of postherpetic neuralgia

“…Previous studies have suggested that the extension of the time of radiofrequency exposure is not an effective method for the treatment of neuropathic pain and excessive exposure is associated with increased neuronal damage [ 13 , 29 ]. In order to assess the optimal thermal coagulation effect in the bipolar procedure more clearly, we explored the radio frequency duration and bipolar distance in the ovalbumin in vitro test [ 30 ].…”

Sacroiliitis: A Review on Anatomy, Diagnosis, and Treatment

“…A prevalent theory describes the modulation of a c-Fos pathway by alternating electric fields generated by PRF [ 20 ]. Another popular theory involves the alteration of the transcription factor ATF3, which ultimately impacts cellular stress in C and A δ pain fibers [ 21 ]. Although more study is needed to elucidate the mechanisms behind this technique, the short-term analgesic effect is significant.…”

“…Although more study is needed to elucidate the mechanisms behind this technique, the short-term analgesic effect is significant. A retrospective study published in 2021 comparing 3 types of radiofrequency techniques (conventional, cooled, and pulsed) for SI joint pain showed the highest rate (100%) of pain relief over a six-month period [ 21 ]. It should be noted that other studies have shown varied rates of effectiveness between these methods, and this likely indicates a need for a more comprehensive study with a larger group of patients.…”