Spinal cord stimulation: principles of past, present and future practice: a review.

Electric energy have been in use for the treatment of various ailments, including pain, since the time of Pharaohs. The theoretical basis of electrotherapy of pain was provided by the Gate Control Theory of Melzak and Wall. In 1965, Shealey et al. first introduced electrical stimulation of spinal cord for treating pain. At present spinal cord stimulation (SCS) is a well established form of treatment for failed back surgery syndrome, complex regional pain syndrome and refractory pain due to ischemia. The indications for SCS is growing and the technology involved in this is rapidly advancing, however, high level of scientific evidence is still lacking to support this form of therapy due to difficulties in blinding and comparing with control groups. Future developments in SCS could include, combined SCS-drug delivery system, bio feedback and closed loop systems.