BJA Advance Access originally published online on May 22, 2007
British Journal of Anaesthesia 2007 99(2):266-269; doi:10.1093/bja/aem129
Effect of pulsed magnetic field therapy on pain reported by human volunteers in a laboratory model of acute pain
1 University Hospitals Coventry and Warwickshire NHS Trust, Clifford Bridge Road, Coventry CV2 2DX, UK
2 Department of Health Sciences and Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Leicester LE1 5WW, UK
* Corresponding author: Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal Infirmary, Leicester LE1 5WW, UK. E-mail: djr8{at}leicester.ac.uk
Background: Pulsed magnetic field therapy (PMFT) is a non-invasive, simple technique used extensively for the treatment of muscle pain. However, evidence to support its use from well-designed, clinical, or experimental studies is sparse.
Methods: We have utilized an acute pain model to perform a randomized, double-blinded, placebo-controlled, crossover-study on 10 male (18–40 yr) volunteers. Pain was elicited by infusion of hypertonic saline 5% into the brachioradialis muscle of the non-dominant arm on two occasions, at least 1 week apart. Subjects received active or sham PMFT for 30 min in a randomized order delivered by two identical, commercially available machines (PulsePack 6000, Quantum Techniks). The active machine delivered a M-wave magnetic pulse (1.25 Hz, 3 ms width, 600 Gauss); the sham device was deactivated and delivered no magnetic energy. Pain was assessed at 15-s intervals, and area under the visual analogue score (VAS) pain curve (AUCp) was calculated using the trapezoid method.
Results: There were no significant differences in mean VAS pain scores between the two machines at any time. In addition, there were no significant differences with respect to mean (SEM) maximum pain score [sham 60 (8), active 63 (9) mm; P = 0.66, 95% CI –18 to 12 mm] or AUCp [sham 463 (50), active 499 (90); P = 0.64, 95% CI –201 to 129].
Conclusions: We conclude that, using the electromagnetic characteristics of the machine in this study, the PMFT had no effect on pain in our experimental model. More work is required to provide an evidence base in support of the use of this technique for pain.
Keywords: analgesic techniques, pulsed electromagnetic field therapy; pain, acute; pain, experimental
Data from this study were presented at the Anaesthetic Research Society meeting, Loughborough, November 2005.