Myelotomy through the years.

Although myelotomy was first designed to treat somatic pain by interruption of the decussating fibers of the spinothalamic tract, it was soon recognized that pain relief may be obtained in a wider distribution than the dermatomes represented by the interrupted nerves. In 1970, Hitchcock described relief of pain throughout the body by stereotactic production of a single lesion in the middle of the spinal cord at the cervico-medullary junction, a procedure named extra-lemniscal myelotomy by Schvarcz several years later. This led me to the observation reported in 1984 that pelvic pain might be controlled by a non-stereotactic lesion at the thoraco-lumbar area, which appeared to be particularly effective against visceral pain of cancer, in a procedure termed limited myelotomy. In 2000, Kim recognized that thoracic pain might be treated by a similar lesion in the high thoracic area, and termed his procedure thoracic dorsal column midline myelotomy. Up to that time, all authors had considered that pain relief was the result of interruption of a multi-synaptic pathway just dorsal to or within the central canal, which had not yet been defined. However, Willis identified a new pathway in the ventromedial dorsal columns in the post mortem spinal cord provided to him by my coauthor, which he further documented by animal physiologic studies. Nauta, at that same institution, reintroduced limited myelotomy based on those anatomical findings, naming the procedure punctate myelotomy. It must be recognized that all of these procedures have involved interruption of the same pathway, even before it was defined anatomically, and all authors provided similar observations about relief of particularly visceral pain.