This procedure is based on the hypothesis that the awareness and debilitating quality of back and leg pain may be lessened by modulating the electrical conductivity of the spinal cord. Modulation of electrical activity is achieved by the surgical placement of electrical leads (wires) in the lower thoracic spinal canal. Typically, the procedure requires a trial prior to definitive implantation. The leads are placed in the epidural space of the spinal canal-outside of the sac that contains the spinal cord. Small electrical impulses are imparted by a ‘pulse generator’ that is implanted in the subcutaneous fat just above the buttock. This procedure has been shown to be effective in treating intractable leg pain secondary to nerve root injuries.