Abstract
Background: Pulsed radiofrequency (PRF) is increasingly used in clinical practice, especially
in neuropathic pain disorders. Although PRF is not new to clinical use, there are significant
gaps in knowledge regarding its effectiveness.
Objectives: The current study was conducted to evaluate the effect of duration of
application of PRF on its analgesic efficacy in improvement of neuropathic pain. Study Design:
A randomized experimental trial.
Setting: An animal research facility at the College of Veterinary Medicine at Mansoura
University in Egypt.
Methods: Chronic constriction of the sciatic nerve of 36 male Sprague-Dawley rats
was performed to induce neuropathic pain. The rats were divided into 6 groups (6 rats
each) in which PRF was applied for 2, 4, 6, or 8 minutes or not at all. In one group, RF
cannula was applied without performing PRF intervention. The pain was assessed through
observation of resting paw posture (RPP) at 3, 10, and 21 days. Nerve damage was assessed
by histopathological evaluation of the sciatic nerve. Immunohistochemical localization of
proinflammatory cytokines (interleukin 6 [IL-6] and tumor necrosis factor alpha [TNF-α]) was
also done.
Results: RPP was improved in rats treated with PRF. This improvement was significant only
in rats treated for 8 minutes. Increased duration for PRF application was associated with a
significant decrease in IL-6 and TNF-α contents in all groups when compared with the control
group. Histopathological evaluation of the constricted sciatic nerve revealed no statistical
significance among the different study groups.
Limitations: The study was limited by the lack of measurement of other inflammatory
markers that may help elucidate other relevant mechanisms.
Conclusions: Increased duration of PRF application resulted in better analgesic efficacy
without any increase in tissue injury in an animal model of neuropathic pain. This effect may
be attributed to decreased production of pro-inflammatory cytokines.
Key words: Pulsed radiofrequency, analgesic, rats, sciatic nerve, duration, neuropathic pain