Pulsed Radiofrequency

The use of high frequency current at 500 kHz called radiofrequency, is well recognized in pain management. When applied close to a sensory nerve, the heat generated in the cells at the electrode tip causes coagulation which is believed to interrupt the pain conduction. The use of radiofrequency heat lesions adjacent to the DRG for the management of nonmalignant pain is becoming more controversial because of its potential neurodestructive nature. For that reason, a nondestructive or minimally destructive technique would be more attractive.

A modified technique, pulsed radiofrequency (PRF) treatment was developed whereby in 1 s two bursts of 20 ms each of an alternating current are delivered. The oscillating frequency of the alternating current is 500 kHz. During one cycle the “active” phase of 20 ms is followed by a silent period of 480 ms to allow for washout of the generated heat. The output is usually set at 45 volts, but if the electrode tip temperature exceeds 42°C, it is decreased to prevent cell damage. This temperature is selected based on the findings that necrosis in various soft tissue cell lines could only be induced by heating to greater than 43°C.

The clinical application of pulsed radiofrequency (PRF) by interventional pain physicians for a variety of chronic pain syndromes, including occipital neuralgia and other peripheral nerves around the head is growing. As a minimally invasive percutaneous technique with none to minimal neurodestruction and a favorable side effect profile, use of PRF as an interventional neuromodulatory chronic pain treatment is appealing. At this time, clinical research regarding the efficacy of PRF is limited but gradually accumulating.

Pulsed radiofrequency has opened new possibilities for the treatment of a variety of chronic pain syndromes, including neuropathic pain syndromes. Twenty years after the first report and more than 200 peer reviewed publications, no complications have been reported making it an attractive option.