6. Utility of the Anesthetic Test Dose to Avoid Catastrophic Injury During Cervical Transforaminal Epidural Injections

Abstract

BACKGROUND CONTEXT: Inadvertent intra-arterial administration of corticosteroids during cervical transforaminal epidural injections has been associated with rare but serious complications including tetraplegia, stroke, and death. The utility of conventional techniques to prevent intravascular injection are known, including aspiration for blood and using live fluoroscopy to visualize vascular uptake of contrast. Unfortunately these measures have not always prevented major complications associated with inadvertent intra-arterial injection. Additional methods to reduce risk have been suggested but have not been formally analyzed. The anesthetic test dose is one such method, used with the following rational. If conventional methods fail to reveal injection into a vulnerable artery, the injection of anesthetic will result in transient symptoms related to vertebral artery or radiculomedullary artery injection. These symptoms allow the physician to avoid the vascular embolic event that would occur with subsequent injection of corticosteroids. No prior study has measured the incidence or utility of a positive anesthetic test dose.