Management of phantom pain with a textile, electromagnetically-acting stump liner: a randomized, double-blind, crossover study.

The treatment of phantom pain is frequently dissatisfying. We wanted to find out whether an electromagnetically shielding stump stocking interwoven with metal (medipro(R)Liner RELAX [medi Bayreuth, Bayreuth, Germany]) could have a positive effect on phantom pain. A double-blind, randomized, crossover trial in a total of 30 leg amputees compared the experimental (=verum) silicon liner (VL) fitted to the amputation stump with a dummy (=placebo) liner (PL). Each liner was worn for two weeks after a two-week baseline period. Daily documentation focused on phantom pain, quality of sleep and improvement of well-being. Twenty-seven of 30 patients completed the 6-week study, and 22 documentations proved valid. On a 0-10 numeric rating scale (NRS), the median pain intensity before treatment was 4, and the median of maximum pain was 6. VL versus PL reduced pain significantly more often (P=0.008), the odds ratio being 5.95. The degree of pain reduction was likewise highly significant (<0.001). Wilcoxon's matched-pairs signed-rank test for the medians of daily maximum pain showed a significant reduction for both PL (P < 0.001) and VL (P <0.001) as compared to baseline, with VL being highly superior again (P < 0.001) versus PL. The experimental device also led to significant amelioration of general well-being (P = 0.037) with an odds ratio of 3.85, and an improvement in the quality of sleep, which was not significantly different than PL (P = 0.223). In this study, the influence of a silicon liner with electromagnetically protecting properties on phantom pain was highly significant. The mechanisms underlying this effect are unclear. Possibilities include reduction of ectopic neuroma activity, shielding from possible electromagnetic weather impulses (sferics), or analgesic effects of changes in the electromagnetic field. PET or fMRI examination with or without a shielding silicon liner might help to elucidate this observation further.