Objective: While there is an extensive body of literature concerning the use of epidural steroid injections in the treatment of sciatica, most of the literature is descriptive or anecdotal. There are few controlled studies regarding efficacy of this treatment modality. While there are few published reports of serious complications of this therapy, warnings about the hazards of epidural steroid injections occasionally appear in both medical and lay literature. It is the purpose of this review to assess the existing evidence for efficacy of epidural steroid injections for sciatica and to assess the risks of this procedure. Data sources: Peer reviewed medical literature from 1930 to the present was reviewed in order to survey reports regarding pathophysiology of radiculopathy, mechanism of action of epidural corticosteroids, controlled efficacy studies, reports on series of epidural steroid injections for sciatica, reports of adverse effects of epidural and intrathecal steroid injections, review articles of epidural and intrathecal steroid injections, and studies of the behavioral and histological effects of epidural steroids and their vehicle in animals. Study selection: Studies and review articles were selected from Medline search and from the author's files of older literature. Data synthesis: Results of this review are qualitative. It was felt that there was insufficient controlled data to analyze efficacy or safety studies in a quantitative fashion. Results: Radiculopathy following disc herniation appears to produce either mechanical or chemical nerve root inflammation. Epidurally injected corticosteroids most likely exert a beneficial effect through anti-inflammatory rather than direct analgesic mechanisms. Most descriptive studies report beneficial effects of epidural steroids in the majority of cases of radiculopathy, but not for other causes of low back pain. Most of the few controlled studies report epidural steroids to be more efficacious than placebo or epidural local anesthetic alone. Most patients who respond favorably continue to show improvement for many months. Several neurologic complications have been reported after intrathecal steroid injections, most following multiple intrathecal injections. Four cases of epidural abscess, one case of bacterial meningitis, and one case of aseptic meningitis have been reported following epidural steroid injections. Conclusions: The majority of the published literature supports the notion that epidural steroids provide relief of pain from lumbosacral radiculopathy. There is anecdotal evidence that multiple intrathecal steroid injections may be associated with neurological dysfunction, but there is very little evidence that epidural steroids are neurotoxic. (C) 1997 Elsevier Science Ireland Ltd.
