Source: Pinto RZ, Maher CG, Ferreria ML, Hancock M, Oliveira VC, McLachlan AJ, Koes B, Ferreira PH. Epidural corticosteroid injections in the management of sciatica: a systematic review and meta-analysis. Annals of Internal Medicine 2012.
Efficacy Endpoints: Pain, disability
Harm Endpoints: Infection, bleeding, nerve damage
Narrative: Sciatica, or the symptomatic pain believed to be associated with lumbar nerve root compression, affects up to 15% of the population. While many individuals achieve resolution with conservative therapy, a sizable minority go on to chronic pain. Epidural steroid injections have been utilized since the 1950s for pain not responsive to conservative treatment. By 2004, almost 1.5 million Medicare patients received such injections.1
The authors of this systematic review included 23 randomized, placebo-controlled trials involving over 2,000 subjects with symptoms of sciatica who had not undergone previous back surgery. The studies examined the efficacy of epidural steroid injections, delivered through one of three approaches (caudal, interlaminar, and transforaminal).
In the short term after injection (2 weeks – 3 months), while back pain was unaffected, leg pain was reduced by 6 points on a pain scale and disability was reduced by 3 points (both scales total 100 points). Validation studies and consensus statements regarding pain and disability scales suggest that a minimum change of 10 to 30 points is required for these effects to be considered clinically meaningful. There was no significant difference seen for back pain in the short term and no significant differences in leg pain, back pain, or disability in the long term (>12 months).
Serious adverse effects of epidural steroid injections are quite rare, but case reports include epidural abscesses, bacterial meningitis, and epidural hematomas. More common adverse effects include intravascular placement, headache, vasovagal symptoms, and local pain.
Caveats: While this review found short-term, statistically-significant reductions in leg pain and disability, the effect size was small and did not meet proposed thresholds for clinical significance. Moreover, steroids were compared to sham injections and not necessarily compared to contemporary conservative management, which may offer benefit, particularly in the short term. No differences were seen in the long term, a finding confirmed by a recent study examining two-year follow up.
Adverse events are rare but potentially serious, as witnessed by a recent cohort of patients who contracted fungal meningitis from contaminated epidural injections.2
The included studies encompassed a large number of patients and varied from fair to high quality. A minority of trials fulfilled complete blinding of providers, allocation concealment, and intention to treat analyses.
Notably, this study examined pain and disability due to sciatica, and not spinal stenosis or undifferentiated low back pain.
Given the clear lack of any clinically significant benefit in both the short and long term, the cost and the small, but real potential for procedural complications, we have chosen to classify this intervention as Red.
Author: Gary Green, MD
Published/Updated: January 11, 2013
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