After baseline measures have been recorded, the research study will be conducted in two phases. Study Phase I will occur during SCS implant surgery. First, an epidural trial SCS lead will be placed in accordance with the normal standard of care for this procedure. Next, a test stimulator (Cadwell ES-5) will be connected to the test lead and intraoperative test stimulation will be delivered for up to 30 minutes to determine the effect of spinal level, amplitude, frequency, pulse width on direct dorsal column stimulation. Sensation thresholds and paresthesia strength and coverage area will be recorded in response to these changes in stimulation parameters. SSEPs will be recorded throughout the procedure (Cadwell Cascade Elite IONM System). These will be recorded using needle electrodes placed on the tibial nerve and the scalp. Next, an Ad-tech subdural trial lead will be inserted in the standard fashion, similar to a standard lumbar drain catheter, and will be connected to the test stimulator. Test stimulation and quantification of responses will be repeated for up to an additional 30 minutes. The test stimulator will be disconnected once test stimulation is complete, and the surgery will continue per the normal standard of care to secure the two trial leads in place for post-operative percutaneous trial SCS.