The purpose of the study is to test the effects of intradural, spinal cord stimulation using a device placed in the same manner as a lumbar drain performed during a standard epidural spinal cord stimulation (SCS) trial routinely performed prior permanent lead and stimulation device implantation.
In this pilot study the investigators will test an ability of intradural electrical stimulation in humans to elicit physiological responses (paresthesia or tingling sensation) and decrease pain when placed in the region of the thoracic spinal cord in a controlled manner. This subject population is comprised of patients that had previously failed various conservative pain management treatment plans and are deemed candidates for treatment of pain by spinal cord stimulation. The investigators will use commercially available device to deliver an intradural electrical stimulation to the spinal cord. This device is FDA approved for intracranial electrophysiological monitoring and delivery of electrical stimulation of the subsurface level of the brain. As a part of the study, the subject will be offered to complete the following questionnaires to assess quality of life and global function. These questionnaires will be completed prior the procedure and at specified time periods following the research intervention. The experimental portion of the procedure will follow the standard epidural spinal cord stimulator testing. Under fluoroscopic guidance, using a paramedian approach and shallow entry angle, the device will be placed percutaneously at the lumbar spine at L2-3 or L3-4 level into the intrathecal cerebrospinal fluid (CSF) space and advanced to the T8-10 disc space. The stimulation catheter will run through a standardized experimental algorithm further described in greater details. The initial stimulation will last approximately 30 minutes and involve testing for paresthesias (tingling) and measurement of the threshold signal strength for onset of this sensation at 60 hertz (Hz) and 10000 Hz frequences. During this portion the subject will be asked to describe the sensations and rate his or her pain on a 0 to 10 scale. Following this initial stimulation, the frequency will be changed to 10 kilohertz (KHz) to run over the period of 4 hours. The investigators will continue evaluating the effects of stimulation using visual analogue scores during this period of time.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
The device will be placed percutaneously at the lumbar spine at L2-3 or L3-4 level into the intrathecal CSF space and advanced to the T8-10 disc space. After positioning of the intrathecal lead, the stimulation catheter will be run through a standardized experimental algorithm consisting on various frequencies.
Subjects will be administered questionnaires to evaluate pain, quality of life, and global function prior the study, at 1 hour after the completion of the study, and at 4 day follow-up appointment.
University of Iowa Hospitals and Clinics
Iowa City, Iowa, United States
Establishment of paresthesia threshold
Observe and record how various stimulation measures induce paresthesias and record this paresthesia threshold. This will be measured by having the patient state when they feel paresthesias as the stimulation amplitude is increased. This will be recorded as a raw number.
Time frame: 30 minutes
Establishment of motor threshold
Observe and record how various stimulation measures induce motor activity and record this motor threshold. This will be measured by having the patient state when they feel motor movement as the stimulation amplitude is increased. This will be recorded as a raw number.
Time frame: 30 minutes
Acute Adverse Pain Responses using short-form McGill Pain Questionnaire
Demonstrate that intradural stimulation does not induce adverse painful responses during acute stimulation. Participants will be administered the short-form McGill Pain Questionnaire prior to start of testing and one hour following testing has concluded. The McGill Pain Questionnaire has a range of scores from zero (min) to 45(max) with lower numbers being better.
Time frame: 5 hours
Acute Adverse Pain Responses using long form Brief pain inventory (BPI)
Demonstrate that intradural stimulation does not induce adverse painful responses during acute stimulation. Participants will be administered the long form BPI prior to start of testing and one hour following testing has concluded. The brief pain index creates a severity and interference score that ranges from zero (min) and 10 (max) with lower numbers being better.
Time frame: 5 hours
Difference in Stimulation Intensity to induce paresthesias
Record the threshold difference in stimulation intensity between epidural and intrathecal stimulation. This will take the data collected from the patient's clinical epidural trial (paresthesia threshold) and compared to the patient's intradural threshold testing.
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Time frame: 90 minutes
Unexpected/Chronic effects of stimulation
Record unexpected or unanticipated effects of stimulation that may limit its utility or conceivably provide a new avenue for neuromodulation not achievable with epidural stimulation. Participants will be contacted via telephone interviewed to screen for any unexpected outcomes.
Time frame: 1 month