Is pulsed radiofrequency a neuromodulation technique?

In this issue of Neuromodulation, J. Van Zundert et al. have published an article titled, Percutane-ous pulsed radiofrequency treatment of the cervi-cal dorsal root ganglion in the treatment of chronic cervical pain syndromes: A clinical audit (1). The question that our readers might ask is this: Is pulsed radiofrequency neuromodulation? It is the opinion of these authors that it is. The exact definition of neuromodulation is hard to find in the literature. Neuromodulation is considered a normal property of the nervous system that regulates or modifies electrical impulses flowing through neural tissues by enhancing, inhibiting , extending, or shortening them. Interventional neuromodulation is considered nondestructive and reversible therapy and includes the use of implanted or nonimplanted electrical stimulation systems, electrically stimulating peripheral nerves, dorsal root ganglia, the spinal cord, or the brain, and chemical neuromodulation, the infusion of chemical agents directly to the central nervous system. Considering that the accepted definition of therapeutic neuromodulation only includes either electrical stimulation of the nervous system or chemical modulation of the nervous system, could we consider the new technique of pulsed radiofrequency of cranial nerves, dorsal root gan-glia and peripheral nerves as neuromodulation? Neuromodulation of nociceptive information takes place in spinal synapses through presynaptic and postsynaptic inhibition. The gate control theory described by Patrick Wall and Ronald Melzack in 1965 postulates that reception and activation of small fiber, nociceptive, afferent information, at the spinal, gray-matter level, is inhibited by activation of large, A-beta afferent fibers, preventing the release of substance P presynaptically (2). Descending inhibitory control is also another example of neuromodulation. There exists a series of descending pathways starting in upper neural centers and terminating in the spinal cord. These upper neural centers, including the nucleus raphe magnus, the paragigantosuperior reticulum, the peri-aquadectal gray, and the substantia nigra can all be activated by direct spinal electrical stimulation or intrathecal chemical neuromodulation, inhibiting the sensation of pain along the descending pathways. As previously stated, therapeutic electrical stimulation of the nervous system includes peripheral stimulation of the nervous system (transcutaneuous nerve stimulation (TENS) (3), and peripheral nerve stimulation (PNS) (4)), spinal cord stimulation (5), and stimulation of deep brain structures and motor cortex (6). Spinal cord stimulation (SCS) acts upon any structure or tract of the spinal cord if the electrical