Background: Selective steroid injections of the lumbar spine carry a risk of paraplegia of sudden onset. Seven cases have been reported in the English literature since 2002.
Materials and methods: Five new cases have been analyzed, all coming from Paris area centers. Injections were performed between 2003 and 2008. The following items were searched for: location of a previous lumbar spine surgery if any, symptoms indicating the procedure, route of injection, imaging technique used for needle guidance, injection of a contrast medium, type of steroid, other drugs injected if any, paraplegia level, post-procedure MR findings. The current and reported cases were compared.
Results: MR findings were consistent with spinal cord ischemia of arterial origin. The high rate of patients who had been operated on in these cases does not correspond to that of patients undergoing injections. The presence of epidural scar might increase the risk. The foraminal route was the only one involved in nonoperated patients. Foraminal, interlaminar, or juxta-zygoapophyseal routes were used in operated-on patients.
Conclusion: The high rate of French cases when compared to the literature might arise from the almost exclusive use of prednisolone acetate, a molecule with a high tendency to coalesce in macro-aggregates, putting the spinal cord at risk of arterial supply embolization.