Background and aims Pulsed radiofrequency (PRF) is a well-recognized treatment modality for chronic pain. However, PRF effects on acute pain are largely unknown. We investigated whether PRF affects acute pain perception and the sense-of-touch in able-bodied subjects.
Methods A single treatment of PRF (42°C; 240 s treatment duration; 10-, 20- and 30-ms pulse duration; 2 Hz) was delivered to the left-sided lower saphenous nerve in 15 able-bodied subjects. Pain and touch sensitivity were assessed in both legs before and at multiple time points after the PRF treatment. Acute pain sensations were elicited by transcutaneous electrical nerve stimulation (9@2ms train; 0.25 Hz). Mechanical stimulation (250-Hz sinusoid) and two-alternative forced choice testing were used to evaluate touch sensitivity. Clinical examination was performed at each visit. The study was approved by Copernicus IRB.
Results Baseline pain thresholds were 13.5±3.1 mA and 13.3±3.7 mA in ipsi- and contralateral legs, respectively. In all subjects, ipsilateral pain thresholds increased immediately after PRF, averaging 17.9±4.5 mA (133.2±23.6% of baseline). Ipsilateral thresholds remained elevated for up to 5–21 days post-PRF, with effects lasting longer (10 days on average) in the 30-ms pulse duration group. No changes in touch sensitivity or clinical examination were observed.
Conclusions The present study demonstrated that PRF treatment in able-bodied subjects increased their acute pain-thresholds for days, while preserving the sense-of-touch. The longer-lasting increase in pain thresholds were associated with longer PRF pulse duration. These findings underscore potential use of PRF in acute pain treatment.