Physiological and Clinical Effects of Radiofrequency-Based Therapy
Radha Kumaran, Binoy
Electrophysical agents (EPA) are a fundamental element of therapy practice and are vital for the treatment of a variety of conditions. Many of these agents employ some form of electromagnetic fields (EMF), in which radiofrequency (RF) is a major component. The therapeutic effects of RF are mainly linked to their effects on pain relief and potential effects on tissue repair. Although RF across various frequency ranges has been in use, reviews have shown that the frequency ranges currently used in therapy practice have narrowed to within 30 kHz–30,000 kHz (30 MHz). The most commonly used and hence the most commonly researched are shortwave therapies (SWT) that operate at 27.12 MHz, which is presently used predominantly in its pulsed form (PSWT). In addition to SWT, devices employing significantly lower RF ranges have also been used widely despite their lack of evidence. Capacitive Resistive Monopolar Radiofrequency (CRMRF) that operates at 448 kHz is one such RF. This programme of research was designed to investigate the physiological and clinical efficacy of CRMRF delivered using the ‘Indiba Activ 902’ device. The project also evaluated the scope and evidence for RF-based EPAs in therapy, through a comprehensive review of literature. A total of 120 relevant clinical studies on either acute (30 studies) or chronic (90 studies) conditions were reviewed. Notable evidence was identified for chronic OA knee and acute postoperative pain and wound healing. Some evidence also exists for chronic low back pain and healing of chronic wounds. Only eight studies reported devices that employed RF outside the shortwave frequency band. In a randomised crossover laboratory study on asymptomatic adults, the effects of contrasting doses of CRMRF on skin temperature (SKT), skin blood flow (SBF), nerve conduction velocity (NCV), deep blood flow and the extensibility of tissues were examined against a placebo dose and a control condition with no treatment. The study further compared CRMRF results with that of PSWT. The results showed that high (moderately thermal) and low (sub/minimally thermal) doses of CRMRF significantly enhanced and sustained SKT (p<0.001), while only the high dose meaningfully increased SBF (p<0.001). High dose PSWT increased SKT marginally (p<0.001) but did not sustain it. Further, the high and low dose CRMRF significantly enhanced blood flow volume at depth (p=0.003), while PSWT failed to show any significant impact. None of the treatments significantly affected deep blood flow velocity, tissue extensibility or NCV. These results were reproduced on a cohort of patients affected by OA knee in a randomised controlled trial (RCT), and the effects appeared more pronounced in the patients than in the asymptomatic people. More importantly, the RCT showed that a four-week high dose CRMRF treatment (eight sessions) produced statistically and clinically significant gains in pain and function associated with OA knee in the short to medium term (p<0.001), which was also significantly more pronounced than the gains produced by a placebo, or standard care (p=0.001for pain; p=0.031 for function). The findings of this study were considered promising. It is therefore suggested that CRMRF-based treatment can potentially be used as an adjunct to current therapeutic methods to enhance the clinical outcomes. However, further studies are needed to substantiate this, and the current results will provide credible baseline data for future research.