The effect of electromagnetic shielding on phantom limb pain: A placebo-controlled double-blind crossover trial.

Background: Environmental electromagnetic fields influence biological systems. Evidence suggests these have a role in the experience of phantom limb pain in patients with amputations. Objectives: This article followed a previous study to investigate the effect of electromagnetic field shielding with a specially designed prosthetic liner. Study design: Randomised placebo-controlled double-blind crossover trial. Methods: Twenty suitable participants with transtibial amputations, phantom pain at least 1year with no other treatable cause or pathology were requested to record daily pain, well-being, activity and hours of prosthetic use on pre-printed diary sheets. These were issued for three 2-week periods (baseline, electromagnetic shielding (verum) and visually identical placebo liners - randomly allocated). Results: Thirty-three per cent of the recruited participants were unable to complete the trial. The resulting N was therefore smaller than was necessary for adequate power. The remaining data showed that maximum pain and well-being were improved from baseline under verum but not placebo. More participants improved on all variables with verum than placebo. Conclusion: Electromagnetic field shielding produced beneficial effects in those participants who could tolerate the liner. It is suggested that this might be due to protection of vulnerable nerve endings from nociceptive effects of environmental electromagnetic fields. Clinical relevance Electromagnetic field shielding with a suitable limb/prosthesis interface can be considered a useful technique to improve pain and well-being in patients with phantom limb pain.