17. Epidural Spinal Cord Stimulation

Spinal cord stimulation was first hosted in 1967 as a technique for treating chronic back pain. In this treatment, the nerves in the spinal column, also called the spine or backbone, are imparted mild electrical impulses or shocks. The impulses are supplied through leads that are implanted into the epidural space. The location of these leads is adjoining the lower facet of the spinal cord between T9 and L1. The implantation is carried out under fluoroscopic control in a relatively minor surgical procedure. The leads are supplied current from the pulse generator positioned between the skin and the fascial layers (connective tissue fibers, largely collagen). The electric impulses interfere with and modify the nerve activity to minimize the sensation of pain propagation to the brain. An additional available feature is programmability of electrode activation. Either constant-voltage or constant-current pulse trains can be chosen. Facility to minimize stimulus energy requirements is provided. The technique is vulnerable to migration of the lead. Shunting of the stimulus currents by the cerebrospinal fluid (CSF) and various other complications diminish its clinical efficacy.