The purpose of this study in patients undergoing routine care epidural spinal cord stimulation (SCS) is to determine 1) whether SCS reduces arterial blood pressure (BP) in patients which chronic low back pain and hypertension, 2) whether higher baseline BP (i.e., hypertension) predicts reductions in pain following SCS, 3) whether SCS alters autonomic and renal function (laboratory markers), and finally 4) whether different SCS waveforms elicits stimulus-evoked compound action potentials (ECAPs) in spinal cord and at the cortex (electroencephalography, EEG).~The Investigators will identify patients with chronic pain who are scheduled for SCS implant at the University of Alabama at Birmingham for management of chronic neuropathic pain as part of routine care. The research team will assess BP with an arm cuff and take blood via blood draw during clinic visits before and after the implant among patients providing written informed consent. A blood draw will also be performed to examine changes in important blood chemistries related to blood pressure.~The Investigators' central clinical hypothesis is that SCS decreases blood pressure in patients with chronic pain and comorbid hypertension. The Investigators further hypothesize that the SCS will improve serological markers of sympathetic nerve activity and kidney function, possibly due to reductions in spinal cord sympathetic nerve activity. A secondary hypothesis is that higher baseline blood pressure predicts larger reductions in blood pressure following SCS implant.~Additionally, this project seeks to expand knowledge on therapeutic mechanisms of SCS via recording electrophysiological responses at the spinal cord (via adjacent, unused SCS contacts) and from EEG scalp recordings over the cerebral cortex.
The purpose of the study is determine 1) whether Spinal Cord Stimulation (SCS) reduces arterial blood pressure (BP) in patients with chronic low back pain and hypertension, 2) whether higher baseline BP (i.e., hypertension) predicts reductions in pain following SCS, 3) whether SCS alters serological markers related to autonomic and renal function (measured by blood test), and 4) whether different SCS waveforms produce different electrical changes at the spinal cord and at the brain (measured from stimulation wire and by electroencephalography, EEG).