A Prospective Single Arm Pilot Study to Investigate the Dynamic Brain and Multifidus Muscle Imaging in Response to Multifidus Stimulation in Patients With Low Back Pain Undergoing Reactiv8 Implant
Overview
- Phase
- Phase 4
- Intervention
- Not specified
- Conditions
- Low Back Pain
- Sponsor
- Barts & The London NHS Trust
- Enrollment
- 20
- Locations
- 1
- Primary Endpoint
- Percent Pain Relief
- Status
- Completed
- Last Updated
- 5 months ago
Overview
Brief Summary
The study involves investigating phenotypic changes (ie metabolic activity in brain pain matrix areas, metabolic activity and textural analysis of multifidus muscle) following multifidus stimulation and establishing relationship with the change in pain, functionality and quality of life.
Detailed Description
Multifidus Stimulation via the dorsal ramus is an effective therapy for patients with intractable low back pain. Barts Health has had a positive experience following the implantation of Reactiv8 stimulator in patients with very good success rate in both in Reactiv8 A \& B studies. Multifidus stimulation (MS) serves an advantage of functional restoration and neuro-rehabilitation in this difficult group of patients of intractable low back pain, however objective measurement of the multifidus stimulation on supraspinal pathways particularly the changes in higher centres in the brain and in the multifidus muscle itself remains to be characterised. Dynamic brain imaging in pain (PET/CT scans) Dynamic brain imaging is increasingly used as a research tool to understand the mechanisms of pain and also pain interventions. This is done by using either a functional MRI (fMRI) or Positron Emission Tomography (PET-CT). The implant used for stimulation of the multifidus muscle is not MRI compatible which precludes the use of fMRI. Hence PET-CT is the best available option to investigate the changes in the brain in patients having MS. Functional changes in the brain are identified by the changes in the regional cerebral blood flow (rCBF) as determined by the changes in the distribution of the radioactiove contrast F18- fluorodeoxyglucose (18-FDG) in different areas of the brain. PET/CT in chronic pain: Chronic pain has been associated with changes in brain structure as well as metabolism especially in the second somatic (SII) regions, insula and anterior cingulate cortex (ACC). Less consistently, changes have also been seen in thalamus and primary somatic area (SI). Sensory discrimination, summation, affect, cognition and attention all seem to influence different areas of the brain there by modulate the patient's pain perception. There is some evidence to suggest that some of these changes may be altered with treatment using either medications or other interventions. PET in spinal cord stimulation (SCS): There is limited data available on functional neuroimaging following SCS. Nishai et al. conducted FDG PET Scanning in 20 patients (7 CRPS and 13 control) and reported increase in FDG (Flurodeoxyglucose) uptake in left thalamus, anterior cingulate cortex, bilateral insula, dorsolateral prefrontal cortex and bilateral temporal gyrus in six patients where SCS is effective. Similarly Kishima et al reported an increase in blood fIow following SCS in thalamus, orbitofrontal, parietal and prefrontal cortex proportional to the pain relief (larger PET assessed increase in rCBF correlates with decrease in pain intensity) It has been postulated that thalamus activity may relate to whether SCS is effective or not. Recent study comparing Tonic Vs Burst frequencies established differential brain pain matrix areas stimulation with PET-FDG demonstrating the fact of Burst being more associated with medial pathway stimulation, hence perception. PET in Dorsal Root Ganglion (DRG) stimulation: Barts Health presented the first data on L2-DRG stimulation for low back pain in virgin back patients, with identifiable changes in cereberal metabolic activity in insula, PAG, cerebral cortex following L2-DRG stimulation. Metabolic activity at the target area was measured as standardized uptake value and response to individual pain matrix were demonstrated following L2 stimulation. SUVmax (maximum standardised uptake value) is one of the most common way to measure glucose metabolism. There is evidence that in patients with brain tumours there is increase in cerebral glucose metabolism (measured with SUVmax before and after cervical spinal cord stimulation). Textural Analysis: Tissue heterogeneity is an important feature associated with adverse tissue biology. Textural analysis has been validated an emerging technique for assessing tissue heterogeneity and quantitative assessments of tissue heterogeneity has the potential to provide non-invasive imaging biomarkers of prognosis and treatment response. Clinical studies have indicated the ability of CT texture analysis (CTTA) to provide independent predictors of survival for patients with malignancies and marker of treatment response. We are utilising the same principal using low dose CT which will be acquired as part of 18F FDG PET-CT image examination. There is no additional radiation exposure for textural analysis. The filtration-histogram method comprises an initial filtration step that highlights image features of a specific size, followed by histogram analysis of the filtered image. The standard descriptors include mean, standard deviation, skewness and kurtosis. There is still limited data on brain imaging within neuromodulation and there is currently no looking at the PET-CT scan changes following multifidus stimulation. Hence this would be the first study looking into the dynamic brain imaging changes following multifidus stimulation. This study aims to investigate the dynamic brain imaging in pain using PET scan in patients who have undergone successful Reactiv8 implantation. This may provide us with information on the nature of changes occurring in the brain following multifidus stimulation in the brain pain matrix. Additionally, we aim to measure the changes in the multifidus consistency and metabolic activity following stimulation. This will also hopefully enable us to correlate it with the changes in clinical and health related outcome questionnaires.
Investigators
Eligibility Criteria
Inclusion Criteria
- •Age ≥22 years, ≤75 years
- •Low Back Pain VAS of ≥6.0cm and ≤9.0cm (on a 10cm scale) at the Baseline Visit.
- •Oswestry Disability Index score ≥21% and ≤60% at the Baseline Visit
- •Chronic Low Back Pain defined as pain and discomfort localized below the costal margin and above the inferior gluteal fold (with or without referred leg pain) that has persisted \>90 days prior to the Baseline Visit, which has resulted in pain in at least half of the days in the 12 months prior to the Baseline Visit, as reported by the Subject.
- •Evidence of lumbar multifidus muscle dysfunction (for example by the Prone Instability Test (PIT)).
- •Continuing low back pain despite \>90 days of medical management including:
- •At least one attempt of physical therapy treatment for low back pain, which may optionally be accomplished over multiple episodes or flare-ups of low back pain.
- •For Subjects with medications prescribed and used for chronic low back pain, usage shall be at a stable dose in the 30 days prior to the Baseline Visit as reported by the Subject.
- •NOTE: A stable dose means the Subject reports no significant change in regular use of medications, which may include PRN use, in the 30 days prior to the Baseline Visit. Typical use must be provided
- •Be willing and capable of giving Informed Consent.
Exclusion Criteria
- •Back Pain characteristics:
- •Any surgical correction procedure for scoliosis at any time, or a current clinical diagnosis of moderate to severe scoliosis (Cobb angle ≥25°).
- •Lumbar spine stenosis, as defined by an anterior-posterior diameter of the spinal canal \<10mm in Subjects with lower extremity pain.
- •Neurological deficit possibly associated with the back pain (e.g. foot drop).
- •Back pain due to pelvic or visceral reasons (e.g.: endometriosis or fibroids) or infection (e.g.: post herpetic neuralgia).
- •Back pain due to inflammation or damage to the spinal cord or adjacent structures (e.g. arachnoiditis or syringomyelia).
- •Pathology seen on MRI that is clearly identified and is likely the cause of the CLBP that is amenable to surgery.
- •Back pain due to vascular causes such as aortic aneurysm and dissection.
- •Leg pain described as being worse than back pain, or radiculopathy (neuropathic pain) below the knee.
- •Source of pain is the sacroiliac joint as determined by the Investigator.
Outcomes
Primary Outcomes
Percent Pain Relief
Time Frame: 24 months
the Subject is asked to report the percent pain relief at the time of the current visit compared to the pain at baseline. The scale is marked at 0% with no change to 100% total change.
Pain and Sleep 3 point index (PSQ-3)
Time Frame: 24 months
The PSQ-3 is an instrument that measures the quality of sleep over a month. This questionnaire is based on 3 questions about sleep and marked as 10cm visual scale where 0 is no problem sleeping to 10 being always having trouble sleeping.
Clinical Global Impression of change
Time Frame: 24 months
Clinical Global Impression - Global Improvement consists of a question comparing the subject's situation at baseline to that at each follow-up visit and it to be completed by the Investigator.
PainDETECT Questionnaire
Time Frame: 24 months
The PainDETECT questionnaire (PD-Q) is a screening tool specifically designed to identify neuropathic pain in an heterogenous low back pain cohort.Scores on the nine-item painDETECT (seven pain-symptom items, one pain-course item, one pain-irradiation item) range from -1 to 38 (worst Neuropathic pain); the seven-item painDETECT scores (only pain symptoms) range from 0 to 35.
Low Back Pain Visual Analog Scale (VAS)
Time Frame: 24 months
The instrument used for evaluating pain is the continuous Visual Analog Scale comprised of a horizontal line 10cm in length, anchored by 2 verbal descriptors. The scoring of the scale 0 represents no pain and 10 being the worst pain imaginable.
Oswestry Disability Index (ODI)
Time Frame: 24 months
Oswestry Disability Index (ODI) is a disease specific assessment of the disabling effects of back pain. Each question is scored on a scale of 0-5 with the first statement being zero and indicating the least amount of disability and the last statement is scored 5 indicating most severe disability.
Subject Global Impression of Change (SGIC)
Time Frame: 24 months
the Subject's overall status since baseline. A 7-point scale that requires the patient to rate the severity of their illness at the time of assessment, relative to the patients's diagnosis.
European Quality of Life Score on Five Dimensions (EQ-5D)
Time Frame: 24 months
The EQ-5D descriptive system comprises the following 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. The answers given to ED-5D can be converted into EQ-5D index an utility scores anchored at 0 for death and 1 for perfect health.