Referred Sensation Areas in Transpelvic Amputee

Electrical stimulation (ES) of referred sensation areas (RSAs) may provide sensory input attempting to alleviate phantom limb pain (PLP). Characterization of referred sensation areas (RSAs) in a 34 year-old male with transpelvic amputation is presented in this paper. PLP was experienced as cramps of muscles of phantom leg and as piercing sensation of the phantom ankle alternating with unpleasant sensation as that given by crawling spiders in an atypical pattern lasting for e.g. 36 hours, with short episodes experienced approximately every 15 seconds on a 7-10 level on VAS scale. RSAs were determined by light brushing of a 350 x 250 mm area around the scar on the amputation site. Combinations of pulse widths of 200 to 600 µs and frequencies from 20 to 120 Hz were used for test of ES of RSAs. Pleasant massaging effect of muscles of phantom leg and of phantom toes, with lasting effect of minutes, was evoked by ES. However, increase of pain level was reported for stimuli of certain parameters and location of electrodes. Sensation evoked by tactile stimulation of given RSA differed of that evoked by ES of the corresponding RSA and neighbour areas. Following ES, increase in non-painful sensations from extended areas of phantom leg was reported as phantom leg coming to life. Furthermore, the phantom leg was perceived lighter and easier to move imaginary. RSAs may qualify for generating sensory input attempting to alleviate PLP, however, thorough analysis of sensation evoked by ES and of pain profile must be performed.