Factors Causing Massive Spasm Following Transection of the Cord in Man

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Abstract
Of twelve patients with mid- and upper-thoracic transections, 5 had no spasm 6-9 mos. after injury; of the remaining 7, the elapsed time between injury and spasm varied from 1-5 mos. The area involved was explored in 5 of the 7 spastic patients; in each cord stump, 1-2 cm. of degenerated area which did not respond to mechanical or electrical stimulation adjoined a zone of anatomical transition and of low threshold, stim. of which was followed by massive spasms. Maximal responses were obtained from dorsal-column or dorsal-root stim., less with ventral-column stim., and only segmental responses with ventral-root stim. Re-moval of the degenerated and adherent tissues was followed by 20%-90% relief of spasm for 2-10 wks., after which the symptoms gradually returned. In 1 patient without spasm, freeing of adhesions was followed in 6 wks. by typical symptoms, indicating that irritation of the "trigger zone" might be partially responsible for the spasm. The dorsal columns were divided at 2 levels in each of 2 patients; "transitory" relief was obtained in 1, 3 mos.'' relief in the other, with accompanying reduction and alteration in tendon jerks and Babinski responses, respectively. The authors conclude that perhaps "release" merely conditions the cord for development of spasm, which is detd. by an "irritative mechanism".