Anterolateral cordotomy for relief of pain, though apparently properly made, is sometimes disappointing. Among the factors which influence the outcome of operation are anatomical variation in the pain conducting pathways,4,9 surgical technique,6,7 and others. It is evident with greater experience with cordotomy that unexpected results are not readily explained by known anatomical and physiological fact.
Retention of hypalgesic areas, especially in the low lumbar and low sacral dermatomes, is not uncommon after cordotomy. The return of pain sensibility several days or weeks after the operation is best explained by inadequate destruction of the pain pathways, the immediate satisfactory sensory level having been due to traumatic operative swelling. When pain sensation recurs months or years after cordotomy, the explanation is, however, more difficult.
King8 has proposed that this phenomenon is due to late gliosis or to an injured but incompletely, severed spinothalamic system. The existence of a multisynaptic