Magnetic resonance spectroscopy across chronic pain disorders: a systematic review protocol synthesising anatomical and metabolite findings in chronic pain patients

Abstract

BackgroundChronic pain is pain greater than 3 months duration that may result from disease, trauma, surgery, or unknown origin. The overlap between the psychological, behavioural, and management aspects of pain suggest that limbic brain neurochemistry plays a role in chronic pain pathology. Proton magnetic resonance spectroscopy (1H-MRS) can evaluate in vivo brain metabolites including creatine, N-acetylaspartate, myo-inositol, choline, glutamate, glutamine, and gamma-aminobutyric acid in chronic pain; however, a comprehensive systemic review of metabolite expression patterns across all brain areas has yet to be performed.Methods and analysisOnline databases including PubMed/MEDLINE, Google Scholar, EMBASE, the Cochrane Library, OVID, and PsycINFO will be searched for articles relating to 1H-MRS and chronic pain. Study inclusion criteria will include ages of between 18 and 65 years with a definite diagnosis of chronic pain, no comorbidities, clearly stated brain volumes of interest, and imaging protocols, with comparisons to healthy controls. Two reviewers will extract data relating to volumes of interest, metabolites, study participant demographics, diagnostic method and pain scores, treatments and duration of treatment, scanner information, 1H-MRS acquisition protocols, and spectral processing software. Where possible, volumes of interest will be reassigned as regions of interest consistent with known regional anatomical and functional properties to increase the power and relevance of the analysis. Statistical analyses will then be conducted using STATA. A central common pathway may exist for chronic pain due to the behavioural manifestations and management similarities between its different types. The goal of this systemic review is to generate a comprehensive neurochemical theory of chronic pain in different brain compartments.Systematic review registrationThis study is registered with PROSPERO CRD42018112640.

A Regions of Interest Voxel‐Based Morphometry Study of the Human Brain During High‐Frequency Spinal Cord Stimulation in Patients With Failed Back Surgery Syndrome

“…Nevertheless, there is a lack of evidence towards investigating therapeutic effects on the supraspinal structures in low back pain. In this study, based on an a priori hypothesis, we investigated for the first time the supraspinal structures during HF‐10 SCS over time in patients with FBSS in specific RoIs involved in chronic pain conditions 24 . This so‐called RoI VBM analysis is more sensitive than a whole‐brain VBM and specifically useful for the evaluation of an a priori hypothesis 42,43 …”

“…This method enables the identification of volumetric changes in local brain regions. More specifically, the following regions were investigated: bilateral hippocampus, thalamus, dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate, posterior cingulate, insular regions, and parietal lobe 24 …”

“…Smoothed GM pre‐processed segments were entered into a 1‐way analysis of variance to investigate volume variances in the RoI’s on a voxel‐by‐voxel based method. The following RoIs were identified: bilateral hippocampus, thalamus, dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate, posterior cingulate, insular regions, and parietal lobe 24 using the Neuromorphometrics atlas in SPM (http://Neuromorphometrics.com).…”

Chronic Pain in Spanish Wildland Firefighters

“…Injuries at work may be one of the reasons why workers report the onset of pain or persistent discomfort over long periods of time (≥3 months) [13,14]. This chronic pain (CP) may end up affecting workers' quality of life and work performance [14], above all in the more physically demanding professions [15].…”

Cortical thickness in chronic pain

“…Numerous studies using a variety of non-invasive neuroimaging techniques in vivo have demonstrated CP-related brain alterations in the neurochemical profile, regional gray matter (GM), regional spontaneous activity, functional connectivity and networks. [ 5 – 16 ] The key altered brain areas, including the sensorimotor, prefrontal, cingulate, and insular cortices in the sensorimotor network, default mode network, and salience network, were not only involved in sensory processing, but also in cognitive-affective processing, which have helped us to understand the maladaptive neurobiological mechanisms leading to the development of CP. [ 17 ]…”