Stereotactic extralemniscal myelotomy.

A procedure is reported in which radiofrequency lesions were stereotactically placed in the central cord region at the cervicomedullary junction to interrupt selectively the extralemniscal system. Physiological recognition of the target site was based upon the homuncular organization of the dorsal funiculi, which is analysed. Only subjective (segmentally unrelated) analgesia was achieved, usually without demonstrable sensory loss. Stimuli were not painful, while ability to localize it and the discrimination between sharp and blunt components were preserved. A rational approach is offered to certain central pain phenomena which resulted in abolition of hyperpathia and disappearance of, or marked reduction in, deep background pain. Both upper and lower body pain were easily dealt with. Pathways for automatic respiration or for micturition were not encroached upon. Therefore it was electively used for cases with diminished respiratory reserve and for cases with midline and/or bilateral pain.