Effect of pulsed magnetic field therapy on pain reported by human volunteers in a laboratory model of acute pain

Abstract

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 welldesigned, 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 218 to 12 mm] or AUCp [sham 463 (50), active 499 (90); P=0.64, 95% CI 2201 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. © The Board of Management and Trustees of the British Journal of Anaesthesia 2007. All rights reserved.