Intradural Percutaneous Stimulation

Study Overview
=================
Brief Summary
-----------------
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.

Detailed Description
-----------------
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.

Official Title
-----------------
Intradural Percutaneous Stimulation - Inducing Physiological Responses.

Conditions
-----------------
Pain, Chronic

Intervention / Treatment
-----------------
* Device: Intradural Spinal Cord Stimulation
* Behavioral: Administration of Questionnaires


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with neuropathic pain and concordant neurological findings previously consented for an epidural spinal cord stimulator trial Patients greater than 18 years of agree Must have one of the following: Diagnosed with medically refractory chronic neuropathic pain, post laminectomy pain syndrome, or failed back surgery syndrome and planning to undergo a spinal cord stimulation trial Been deemed refractory to all other treatments and would otherwise receive an intrathecal catheter/pump for chronic narcotic administration Disease duration of at least 6 months with no lasting success with standard therapies or medications with exception of spinal cord stimulation Mean pain intensity of a least 5 (or greater) measured on a visual analogue scale from 0 (no pain) to 10 (severe pain) MRI or CT Myelogram of the lumbar and thoracic spine (within 12 months prior to screening) No compressive spinal pathology or intradural implants (eg., syrinx shunt tubes) Psychological screening has been completed and the patient has been cleared by a psychologist or psychiatrist as a suitable SCS candidate Female patients of childbearing potential must have a negative serum pregnancy test Patients agree to comply with the study protocol and have reviewed and given written informed consent Exclusion Criteria: Patients who are unable or unwilling to provide feedback regarding the response Subject has an existing intrathecal drug pump Pain is attributed to: vascular disorder; musculoskeletal disorder; substance abuse or withdrawal; infection; disorder of homeostasis Subject is currently enrolled in another trial History of coagulation disorders or patients on chronic anticoagulant or antiplatelet therapy that is not able to be safely held for 14 days History of thoracic trauma or spinal surgery extending into the thoracic spine History of arachnoiditis or intradural spinal surgery that would limit catheter insertion to the target site Current clinically significant or disabling chronic pain problem or condition that is likely to confound evaluation of the study endpoints (i.e. chronic migraine, significant arthritis of the hip associated with primary groin pain complaint) Radiographic evidence of frank spinal instability (gross mobile spondylolisthesis or abnormal subluxation requiring fusion, calcific arachnoiditis, or severe thoracic or lumbar stenosis Subject has a condition that requires diathermy or repeated MRIs New medication for pain initiated within 8 weeks prior to initial baseline research evaluation Life expectancy less than 3 months Systemic infection or local infection of the spine or skin in the anticipated region of catheter insertion. Immune deficiency or history of post surgical infection Female candidates of childbearing potential who are pregnant (confirmed with a positive serum pregnancy test), not using adequate contraception as determined by the investigator, or nursing (lactating) a child Untreated or active psychiatric condition Complex regional pain syndrome or other condition that could limit testing or aggravate an ongoing medical condition Unresolved issues of secondary gain (i.e. litigation) The investigator deems that the subject is not suitable for the study even if they meet all other inclusive/exclusion criteria

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: All subjects enrolled in this study will undergo Intradural Spinal Cord Stimulation.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Single Arm<br>Intradural Spinal Cord Stimulation; Administration of Questionnaires | Device: Intradural Spinal Cord Stimulation<br>* 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.<br>Behavioral: Administration of Questionnaires<br>* 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.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 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. | 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. | 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. | 5 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 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. | 1 month | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Percutaneous Electrical Nerve Stimulation