LUMBAR SUBARACHNOID ETHYLENEDIAMINETETRAACETATE INDUCES HINDLIMB TETANIC CONTRACTIONS IN RATS - PREVENTION BY CACL2 PRETREATMENT - OBSERVATION OF SPINAL NERVE ROOT DEGENERATION

Disodium ethylenediaminetetraacetate (Na2EDTA) has replaced sodium bis ulfite as the antioxidant in 2-chloroprocaine, Nesacaine CE. This stud y was undertaken to determine whether this new formulation has neuroto xic effects when administered in the subarachnoid space. Sprague-Dawle y rats receiving subarachnoid injections of 1.5 mM or higher concentra tions of Na2EDTA immediately initiated a circling behavior that was fo llowed by the development of tetanic contractions of the hindlimbs las ting for 15-20 min. The tetanic contractions were followed by a brief period of hindlimb paralysis. Pretreatment of rats by subarachnoid inj ections of 1 mM CaCl2 prevented the development of tetanic contraction s and paralysis of the hindlimb. Histologic examination of animals rec eiving Na2EDTA revealed moderate to severe focal degenerative changes in spinal nerve roots. Control rats receiving subarachnoid injections of normal saline solution did not develop tetanic contraction nor path ological changes on light microscopy. These results suggest that the p reservative used in Nesacaine-MPF may be neurotoxic.