Direct Comparison of Spinal Cord Stimulator Parameter Settings

(Primary) 1. To compare the clinical effects and side effects of two different stimulation strategies that do not produce any sensory percept (1000 Hz and placebo) on clinical benefit for electrodes implanted for chronic pain as measured by the Visual Analog Pain Scale for back and leg pain, the Brief Pain Inventory, the 36-Item Short Form Survey (SF-36), and the Pain Vigilance and Awareness Questionnaire. (Secondary) 2. To compare the clinical effects of the subthreshold (paresthesia-free) stimulation patterns with conventional (paresthesia-producing) stimulation patterns to evaluate the necessity of paresthesias and current amplitudes on clinical benefit for pain. 3. To identify the ability of subthreshold high-frequency to improve axial pain or the affective component of pain.