Skip navigation

Putting it into your back!

Watts & Silagy [1] performed a meta-analysis on the efficacy of epidural corticosteroids in the treatment of sciatica, and analysed outcomes over the short-term (<60 days) and long-term (up to 12 months). The short-term outcome was more than 75% pain relief, and the long-term outcome was improvement. The authors did not distinguish between saline and local anaesthetic in their "placebo" controls.

This nice paper did the usual thing of concentrating on odds ratios, which are not the most user-friendly output. A subsequent letter [2] did the conversion to NNTs.

Short-term efficacy

Compared with placebo, ten trials had a combined response rate of 58% of 243 treated patients and 40% in 267 placebo controls. The NNT was 6 (4 - 12). That means that one of six patients treated with epidural corticosteroid had effective (>75% pain relief) pain relief within 60 days who would not have done had they been given a placebo injection.

Long-term efficacy

Compared with placebo, five trials had a combined response rate of 51% of 241 treated patients and 41% in 318 placebo controls. The NNT was 11 (6 - 90). That means that one of eleven patients treated with epidural corticosteroid had effective pain relief within one year who would not have done had they been given a placebo injection.

Putting it into context

For patients with chronic disease, and in this case chronic painful disease, interventions may be attractive even if their success rate is far lower than would be acceptable in, say, the management of postoperative pain. The art of clinical practice will then come into play, as patient and doctor juggle the risk and benefit of the alternatives, albeit with better data than we have at present.

For long-term benefit, the only study that was itself significantly different from control was a comparison with saline. There was no significant long-term benefit for local anaesthetic plus steroid over local anaesthetic.

References:

  1. RW Watts, CA Silagy. A meta-analysis on the efficacy of epidural corticosteroids in the treatment of sciatica. Anaesthesia and Intensive Care 1995 23: 564-9.
  2. HJ McQuay, A Moore. Epidural steroids for sciatica. Anaesthesia and Intensive Care 1996 24:284-5.



previous or next story in this issue