Spinal Cord Stimulation and Functional MRI

Study Overview
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Brief Summary
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The overall objective of this study is to assess patterns of fMRI cortical activation with spinal cord stimulation (SCS) in patients with neuropathic leg pain and therefore define cortical correlates, as well as to investigate cortical representations of pain and pain relief and the interactions therein, in the setting of neuropathic leg pain and SCS.

Detailed Description
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The main objective is to define, using functional magnetic resonance imaging, the effects of spinal cord stimulation (SCS) on cortical and subcortical BOLD effects in patients with neuropathic leg pain. Our hypothesis is that SCS will demonstrate a consistent pattern of BOLD activation that will correlate with symptomatic improvement.

Official Title
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Investigating the Cortical Correlates of Spinal Cord Stimulation Using Functional Magnetic Resonance Imaging

Conditions
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Complex Regional Pain Syndrome (CRPS), Neuropathic Leg Pain

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-55 years at time of enrollment. Have previous implantation of thoracic epidural Medtronic Restore Ultra, Prime Advanced and Restore Advanced SCS in place for the treatment of CPRS-type 1 or chronic refractory neuropathic leg pain following FBSS. The implantation must be 3 or more months prior to enrollment. Patient must have reported significant pain improvement (>50%) following implantation of the SCS. Have consistently reproducible pain relief (> 50%) within 10 minutes of switching SCS from an OFF state to an ON state (with optimal parameters - see below). The SCS battery is implanted in the buttocks region. Unilateral or bilateral extremity pain. Able to provide informed consent. Exclusion Criteria: - Contraindication to MRI such as: SCS lead in the cervical epidural region Cardiac pacemaker Intracranial aneurysm clips, metallic implants or external clips within 10mm of the head Metallic foreign metals within the orbits Pregnancy; (urine pregnancy test will be done to confirm) Claustrophobia Pattern of response to spinal cord stimulation Inconsistent response of pain to spinal cord stimulation Long interval (> 10 minutes) before pain relief following switching SCS from an OFF state to an ON state (with optimal parameters) - long washout period Lack of significant pain improvement (< 50%) following implantation of SCS Positive history of significant brain lesions or pathology including: Prior ablative neurosurgery History of large vessel strokes or brain tumors Psychological Screening

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| functional MRI testing<br>fMRI scanning with SCS on and off at different settings. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effects of spinal cord stimulation on patients with neuropathic leg pain through fMRI analysis | We are analyzing the data from fMRI scans to understand more the functional activation of the cerebral cortex | 1 year |