Cauda equina syndrome after spinal tetracaine: Electromyographic evaluation-20 years follow-up

CAUDA equina syndrome (CES) has long been recognized as a rare complication of spinal anesthesia.(1) CES has been described after administration of sp inal anesthetics with lidocaine(2) and bupivacaine.(3) In 1991,(4) CES was reported after continuous spinal anesthesia with 1% tetracaine. In 1980, at our university hospital, six adult female patients underwent perineal gyne cologic surgery using a spinal anesthetic of 2 ml tetracaine, 1.2%, in 10% glucose. The concentration of the injected tetracaine was unknown by the an esthetists. In all cases, lumbar puncture was performed at the L3-L4 inters pace with a disposable spinal needle while the patients were in the sitting position. CES was first diagnosed 72 h or later postoperatively; previous diagnosis was not possible because patients had an indwelling urethral cath eter. The diagnosis of CES was confirmed in all patients. During the past y ear, after institutional approval and informed consent, clinical, magnetic resonance imaging, electromyographic examinations, and conduction studies w ere performed in three of the above patients. Examinations were not possibl e on the other three patients because one had recently died, another could not be located, and the third refused to participate. T1 and T2 magnetic re sonance image readings were obtained with Gadolinium contrast from a 0.5 Te sla General Electric apparatus (General Electric, Tokyo, Japan). Bilateral sensory and motor conduction studies of the sciatic nerve branches were obt ained using a two-channel Nihon-Kohden Neuropack 2 (Nihom-Kohden Corporatio n, Tokyo, Japan). Electromyography was performed in accordance with convent ional techniques.(5,6)