Introduction: Epidural steroid injections are frequently used for the treatment of low back pain and sciatica. The use of steroid injections, however, is under debate.

Objective: To assess the efficacy of epidural steroid injections for low back pain and sciatica, and to investigate whether the widespread use of epidural steroid injections is supported by the results of well conducted randomized clinical trials.

Methods: Literature search with computerized databases (Medline, Embase) for randomized clinical trials evaluating the efficacy of epidural steroid injections, covering the period 1966-1993. All publications were assessed for their methodological quality by two reviewers independently using a set of methodological criteria. The outcomes of the trials are presented in relation to their methodological quality.

Results: We identified 12 therapeutic trials. The methods scores of the trials ranged from 17-72 points (maximum = 100 points). Eight trials showed method scores of 50 points or more. Of the four best studies (>60 points), two reported positive results and two reported negative results of epidural steroid injections. Overall, six studies indicated that the epidural steroid injection was more effective than the reference treatment, and six reported it to be no better or worse than the reference treatment. There appeared to be no relation between the methodological quality of the trials and the reported outcomes.

Discussion: There are flaws in the design of most studies.The best studies showed inconsistent results of epidural steroid injections. The efficacy of epidural steroid injections has not yet been established. The benefits of epidural steroid injections, if any, seem to be of short duration only. Future research efforts are warranted, but more attention should be paid to the methods of the trials.