The primary aim of this study is to investigate cerebral mechanisms of burst stimulation in Failed Back Surgery Syndrome (FBSS) patients treated with Burst Spinal Cord Stimulation (SCS) for chronic back and leg pain. This study is a single center, prospective, blinded, randomized crossover trial with two 14 days treatment periods and two treatment arms (burst before sham stimulation or sham before burst stimulation).
Background and rationale: Tonic spinal cord stimulation for chronic primarily neuropathic pain har been used for over 50 years. Tonic stimulation in frequencies from 20 to 70 Hz produces analgesia and paresthesia in the targeted area. Burst stimulation, a novel spinal cord stimulation pattern, is an intermittent high frequency parenthesis-free therapy. This stimulation pattern consist of 5 spikes with an inter-spike frequency of 500 Hz, delivered at 40 Hz. Clinical effectiveness and noninferiority of Burst stimulation has been proved. A few studies suggest that Burst stimulation induce different activities in cerebral pathways, compared with tonic stimulation. Patient reported attention to pain assessed by the pain vigilance and awareness questionnaire (PVAQ) seems to differ between burst and tonic spinal cord stimulation. This trial is designed to investigate cerebral mechanisms of burst stimulation, using PET O15-water measured blood flow and tissue perfusion as a proxy for cerebral activity. Key events in study implementation: Study phase 1 * Study Inclusion and baseline visit. * Implantation of spinal cord stimulation system. Study phase 2: * Study visit 1(study day 0): Collection of Patient Reported Outcome Measurements (PROM) data, Randomization to study sequence, blood sampling, PET 0, programming of SCS-system. * Study visit 2 (study day 14): Blood sampling, PET 1, collection of PROM-data, SCS system switched off for washout. * Study visit 3 (study day 21): Collection of PROM-data, programming of SCS-system, blood sampling. * Study visit 4 (study day 35): Blood sampling, PET 2, collection of PROM-data, programming of SCS-system.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
All implanted hardware manufactured by S:t Jude Medical/Abbot: Implantable Pulse Generator (IPG): Proclaim™ Elite 5 IPG, model 3660. Electrode: Octrode percutaneous lead, 60 cm, model 3161. Anchor: Long lead anchor, model 1106.
All implanted hardware manufactured by S:t Jude Medical/Abbot: Implantable Pulse Generator (IPG): Proclaim™ Elite 5 IPG, model 3660. Electrode: Octrode percutaneous lead, 60 cm, model 3161. Anchor: Long lead anchor, model 1106.
Uppsala University Hospital, Uppsala University, Dept. of Surgical Sciences and Dept. of Medicinal Chemistry, Div. of Molecular Imaging.
Uppsala, Sweden
Change in regional cerebral blood flow measured with 15O-water Positron Emission. Tomography (PET)
35 Volume of Interest (VOI) will be applied to each PET scan using the PVElab software. Cerebral blood flow (CBF) and perfusable tissue fraction (PTF) will be calculated for each VOI at each scan. Same tests will be done at voxel level with the Statistical Parameter Mapping Software (SPM12), to identify areas with changed CBF or PTF that do not correspond to VOI in the template.
Time frame: PET is performed at study day 0 (baseline), day 14 and day 35.
Semiquantitative assessment of protein levels associated with inflammation.
Level of normalized protein expression (NPX) in plasma, assessed by a multiplex proximity extension assay panel (Olink Bioscience, Uppsala, Sweden).
Time frame: Measured at day 0 (baseline), day 14, day 21 and day 35.
Back and leg pain
Measured using a 100mm Visual Analog Scale (VAS) for back and leg pain, respectively. Scale range: 0 mm indicates no pain (minimum), 100 mm indicates worst imaginable pain (maximum).
Time frame: Measured at visit day 0 (baseline), day 14 and day 35.
General pain
General pain measured by Brief Pain Inventory (BPI) item 3, 4, 5 and 6
Time frame: Measured at day 0 (baseline), day 14 and day 35.
Pain inference
Measured by BPI item 9A-9G
Time frame: Measured at day 0 (baseline), day 14 and day 35.
Disability
Disability measured by Oswestry Disability Index (ODI).
Time frame: Measured at day 0 (baseline), day 14 and day 35.
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TRIPLE
Enrollment
12
Pain Catastrophizing
Measured by Pain Catastrophizing Scale (PCS).
Time frame: Measured at day 0 (baseline), day 14 and day 35.
Pain Vigilance and Awareness
Measured by the Pain Vigilance and Awareness Questionnaire (PVAQ).
Time frame: Measured at day 0 (baseline), day 14 and day 35.
Global Impression of Change
Impression of change in health status assessed by the inventory Patient Global Impression of Change (PGIC).
Time frame: Measured at day 14 and day 35.
Depression
Symptoms of depression is assessed by the inventory Patient Health Questionnaire (PHQ-9).
Time frame: Measured at day 0 (baseline), day 14 and day 35.
Anxiety
Symptoms of anxiety is assessed by the inventory Generalized Anxiety Disorder Screener (GAD-7).
Time frame: Measured at day 0 (baseline), day 14 and day 35.