ABSTRACT
Spinal cord stimulation (SCS) is probably the most commonly performed surgical procedure for pain treatment in the United States, although the exact mechanism of its action remains largely unknown [1]. Several theories have been proposed to explain the pain suppressive effect of SCS. The most commonly accepted of these is the well-known ‘‘gate-control’’ theory of Melzack and Wall [2], which postulates the existence of a ‘‘gate’’mechanism in the central nervous system that controls the processing and transmission of sensory information, including the nociceptive input. According to this theory, the impulse transmission in the nociceptive afferent pathway is modulated by activity in large-caliber myelinated non-nociceptive A-fiber afferents. Therefore, electrical stimulation of these large fibers anywhere along their course in the peripheral nerves or in the dorsal columns of the spinal cord can block central pain signaling.
