Spinal cord stimulator therapy provides direct electrical stimulation to the spinal cord by interfering with the brain’s processing neural information from the pain pathways. A trial placement of percutaneous electrodes is required to determine whether it will provide adequate pain relief. After the leads have been placed, the patient is monitored for 5 to 7 days to determine whether this procedure provided adequate pain relief and improved functional status. A trial is determined to be successful if a patient experiences greater than 50% pain relief and functional activity increases. One of the indications for use of spinal cord therapy is chronic pain from failed back surgery.