Neurological complications of epidural and spinal techniques

Abstract

Summary The background risk of neurological injury from ‘natural’ causes is small and imprecisely known. The evolution of interventional pain management has exacted its own toll of side-effects and neurological risk. When these two are superimposed it is often difficult, or impossible, to discern the separate parts of the final picture and it is only through a knowledge of both sets of side-effects that the viewer can glimpse the true part played by each. To catch that glimpse and to avoid potential complications requires vigilance, and vigilance must be sustained from the time the patients is seen until the remote effects of the analgesic procedure have completely dissipated. In the case of intraspinal steroids this implies a time span of up to 6 weeks ( Bromage, 1993a ). Next in importance to vigilance comes speed of appropriate therapeutic response, since the period of grace to rescue a compromised spinal cord is in the range of 6–12 h. Extraordinarily rapid advances in imaging techniques have made a tremendous contribution to the speed, safety and precision of neurological diagnoses when complications do arise. Today, MRI, with or without gadolinium enhancement, has virtually replaced ionized radiography as the premier imaging technique, and it has supplanted myelography except in cases where MRI is unavailable, or when patients are unable to undergo MRI because of claustrophobia or an implanted cardiac pacemaker ( Sze et al, 1989 ; Byrne, 1992 ). MRI is now moving towards motion images that will provide dynamic capabilities comparable to those of cineradiography ( Sze, 1992 ). While MRI is expensive, the savings achieved by eliminating earlier diagnostic procedures have made it a cost-effective instrument, well suited to the current era of rigorous cost containment ( du Boulay et al, 1990 ).