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Johnson S, Marshall A, Hughes D, Holmes E, Henrich F, Nurmikko T, Sharma M, Frank B, Bassett P, Marshall A, Magerl W, Goebel A. Mechanistically informed non-invasive peripheral nerve stimulation for peripheral neuropathic pain: a randomised double-blind sham-controlled trial. J Transl Med 2021; 19:458. [PMID: 34742297 PMCID: PMC8572078 DOI: 10.1186/s12967-021-03128-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/23/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Induction of long-term synaptic depression (LTD) is proposed as a treatment mechanism for chronic pain but remains untested in clinical populations. Two interlinked studies; (1) A patient-assessor blinded, randomised, sham-controlled clinical trial and (2) an open-label mechanistic study, sought to examine therapeutic LTD for persons with chronic peripheral nerve injury pain. METHODS (1) Patients were randomised using a concealed, computer-generated schedule to either active or sham non-invasive low-frequency nerve stimulation (LFS), for 3 months (minimum 10 min/day). The primary outcome was average pain intensity (0-10 Likert scale) recorded over 1 week, at 3 months, compared between study groups. (2) On trial completion, consenting subjects entered a mechanistic study assessing somatosensory changes in response to LFS. RESULTS (1) 76 patients were randomised (38 per group), with 65 (31 active, 34 sham) included in the intention to treat analysis. The primary outcome was not significant, pain scores were 0.3 units lower in active group (95% CI - 1.0, 0.3; p = 0.30) giving an effect size of 0.19 (Cohen's D). Two non-device related serious adverse events were reported. (2) In the mechanistic study (n = 19) primary outcomes of mechanical pain sensitivity (p = 0.006) and dynamic mechanical allodynia (p = 0.043) significantly improved indicating reduced mechanical hyperalgesia. CONCLUSIONS Results from the RCT failed to reach significance. Results from the mechanistic study provide new evidence for effective induction of LTD in a clinical population. Taken together results add to mechanistic understanding of LTD and help inform future study design and approaches to treatment. Trial registration ISRCTN53432663.
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Affiliation(s)
- Selina Johnson
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK. .,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.
| | - Anne Marshall
- Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Dyfrig Hughes
- Centre for Health Economics and Medicines Evaluation (CHEME) Department, Bangor University, Bangor, Wales, UK
| | - Emily Holmes
- Centre for Health Economics and Medicines Evaluation (CHEME) Department, Bangor University, Bangor, Wales, UK
| | - Florian Henrich
- Department of Neurophysiology, Mannheim Centre for Translational Neurosciences, Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Heidelberg, Germany
| | - Turo Nurmikko
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK
| | - Manohar Sharma
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK
| | - Bernhard Frank
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | | | - Andrew Marshall
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Walter Magerl
- Department of Neurophysiology, Mannheim Centre for Translational Neurosciences, Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Heidelberg, Germany
| | - Andreas Goebel
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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