Failure of transcutaneous electrical stimulation to alleviate experimental tourniquet pain

It has been proposed that transcutaneous electrical nerve stimulation (TENS) acts by stimulation of large nerve fibers which inhibits further propagation of nociceptive input conducted along smaller C-nerve fibers. We evaluated the effectiveness of TENS in alleviation of ischemic pain (C-fiber mediated) experimentally produced by the submaximal-effort tourniquet test. Cutaneous electrodes were placed proximal to the tourniquet and TENS was begun prior to exsanguination of the arm. Time from inflation of the tourniquet to onset of intolerable pain was noted together with a visual analog-derived intensity of pain for 10 subjects studied on three separate occasions. The results showed no statistically significant prolongation in the duration of ischemia tolerated nor reduction in the subjective intensity of pain during either single- or dual-channel stimulation in comparison to control levels.