Transcutaneous electrical nerve stimulation (TENS)
TENS is a stimulation procedure to activate endogenous pain inhibition systems at the spinal and supra-spinal level. Electrodes are applied to the skin in the region of the pain, in the direct vicinity, or also over trigger or acupuncture points, and set at a special frequency, usually depending on the nature of the pain.
Acupuncture is a method of treatment originating from Chinese medicine, which has been very successful in the treatment of pain. Fine needles are inserted into the cutaneous areas with an accumulation of sensory cells (acupuncture points). Pain-inhibiting substances, e.g. endorphins, are thus presumably released, which inhibit the transmission of the pain impulse. In addition, an electrical current can be applied to the needles.
The basic principal of neurosurgical procedures is the interruption of the transmission pathways which transmit the pain stimuli from the damaged tissue. In chordotomy the spinothalamic tract is interrupted in the spinal cord. A less radical method is radicotomy, where surgery is not performed directly in the spinal cord, but the nerve root is severed at its exit from the spinal column. Peripheral nerves may also be blocked, either reversibly with local anaesthetics as transmission blockade or irreversibly as neurolysis using neurolytics (alcohol, phenol, etc.), electrocoagulation or irradiation. As these techniques cause permanent nerve damage, they are “last resort” treatments for the relief of very severe intractable pain.