Although epidural corticosteroid injections for sciatica pain have become somewhat commonplace, existing guidelines and systematic reviews provide inconsistent recommendations on this interventional procedure. So, an Australian team of investigators conducted a new systematic review and data meta-analysis to determine the efficacy of epidural corticosteroid injections compared with placebo for sciatica [Pinto et al. 2012].
Numerous databases were searched for reports of randomized, placebo-controlled trials (RCTs) that included only patients diagnosed with sciatica (ie, radiating leg pain) or a proxy condition, such as radiculopathy, nerve root compromise or compression, lumbosacral radicular syndrome, disc herniation, radiculitis, nerve root pain or entrapment. Studies reporting any of the 3 anatomic approaches to deliver corticosteroids into the epidural space — ie, caudal, interlaminar, and transforaminal [discussed in a prior UPDATE here] — were eligible. Trials were excluded if they involved patients with sciatic symptoms due to spinal canal stenosis or who had previously undergone surgery.
Data reflecting leg pain, back pain, and physical disability were converted to common scales from 0 (no pain or disability) to 100 (worst possible pain/disability). The threshold for clinically important changes was considered to be in the range of 10 to 30 points, and effects were calculated for short-term (>2 weeks but ≤3 months) and long-term (≥12 months) follow-up. Data in the meta-analysis were pooled using conservative random-effect modeling, although the highest value of I² was 22% suggesting, at most, low heterogeneity across trials [see recent UPDATE discussing these concepts here].
Writing in an early online edition of the Annals of Internal Medicine, the researchers report that their search discovered 25 qualifying papers (presenting 23 RCTs) for review and analysis. Overall, group sizes for analysis were adequate and the evidence was graded by Pinto and colleagues as being of high quality.
Pooled results showed a statistically significant, but small, effect of epidural corticosteroid injections compared with placebo for leg pain in the short term (14 RCTs; N=1,316; mean difference, –6.2; 95% CI, –9.4 to –3.0) and also for disability in the short term (10 RCTs; N=1,154; mean difference, –3.1; 95% CI, –5.0 to –1.2). Followup long-term, one year later, demonstrated pooled effects for pain and disability that were smaller and not statistically significant.
Similarly, no significant benefits of the injections were observed in helping to relieve sciatica-associated back pain (6 RCTs; N=723). There were no differences in effect between the 3 epidural injection approaches, and insufficient data were available for the authors to comment on adverse effects and safety associated with the intervention.
The researchers conclude the available evidence suggests that epidural corticosteroid injections offer only short-term relief of leg pain and disability for patients with sciatica. Additionally, the small size of these treatment effects are not likely to be clinically meaningful for patients, and no relief of back pain or disability in the presence of sciatica is afforded by this intervention.
COMMENTARY: Sciatica is a common type of lower back pain characterized by intense unilateral leg pain, tingling or numbness, and shooting pain that often radiates below the knee. Symptoms relating to nerve inflammation and/or compression can be debilitating and persistent — afflicted patients are nearly 4 times more likely to have back surgery as compared with those who have ongoing low back pain only. Conservative treatment options often offer little relief, so more invasive procedures such as epidural corticosteroid injections have become increasingly popular.
In an earlier UPDATE on this topic last January [here] we noted that nearly 9-million persons in the United States alone received epidural steroid injections during 2010 and rates were increasing. However, as Pinto et al. found in this current study, benefits are short-lived at best and of little clinical significance for sciatica. At the same time, there has been growing concern about adverse events, some very serious, associated with the intervention and the U.S. Food and Drug Administration is reviewing the safety of these procedures, particularly when the transforaminal approach is used. The recent fungal meningitis outbreak in the U.S. tied to tainted epidural steroid injections has heightened concerns.
Still, evidence from recent systematic reviews is accumulating to suggest that there may be no single, optimal treatment for sciatica applicable to all patients with the condition. For example…
- Earlier this year the same investigative team as in this present study, led by Pinto, published in the British Medical Journal a systematic review and meta-analysis examining the efficacy and tolerability of analgesic and adjuvant drugs used in the conservative treatment of sciatica [discussed in UPDATE here]. Among the 23 published reports qualifying for inclusion, none demonstrated robust and clearly significant clinical benefits of selected NSAIDs, oral corticosteroids, antidepressants, anticonvulsants, muscle relaxants, or opioid analgesics as compared with placebo.
- As noted in prior Cochrane systematic reviews [see UPDATE here], spinal manipulative therapy (SMT, or chiropractic) was demonstrated as no more effective in patients with acute or chronic low-back pain — including conditions with radiating pain into the buttocks and/or legs — than inert interventions, sham SMT, or when added to another intervention. Chiropractic also appeared to be no better than other commonly recommended active therapies.
- Another Cochrane review examined the relative benefits of rest in bed versus staying active in patients with acute lower back disorders (<6 weeks), with or without sciatica [see UPDATE here]. Ten qualifying RCTs (N=1,923 subjects) were examined and there were little or no differences between the two approaches demonstrated in patients with sciatica. Furthermore, it appeared doubtful that other treatment strategies — eg, physiotherapy, spinal manipulation, or exercise programs — conferred greater benefits than merely staying generally active.
- In cases of specific pathology, such as lumbar disc herniation, surgery has been generally considered an effective approach. Yet, a systematic review of studies comparing surgery with more conservative approaches found mixed results [Jacobs et al. 2011]. One large, high-quality trial comparing surgery with usual conservative care found no statistically significant differences on outcome measures after 1 and 2 years. Another large trial suggested that early surgery in patients with 6 to 12 weeks of radicular pain may lead to faster pain relief when compared with prolonged conservative treatment; but, again, there were no differences between approaches after 1 and 2 years followup.
Together, recent reviews of clinical trials do not paint a very optimistic picture when it comes to effective evidence-based treatments for sciatica. However, it also should be noted that large numbers of trials of adequate quality were unavailable for most of the reviews, and in many cases there were so many differences in methodology across studies (heterogeneity) that reliable and precise data meta-analyses could not be performed. Also, multimodal approaches, combining therapies in a comprehensive pain/disability management program, were not studied.
Further, as is typical of pain research trial designs, data reflect average responses of patients within experimental and control groups; whereas, clinicians are most interested in how individual patients will respond. Even in cases of equivocal outcomes, a certain percentage of patients was likely helped by the active therapy under investigation even though the group as a whole may have been less responsive.
Recommended therapeutic approaches to sciatica generally fall within evidence-based guidelines for the treatment of lower back pain; although, the most current reviews regarding sciatica, as described above, have yet to be incorporated in those documents. Even so, some research has suggested that a majority of practitioners are noncompliant with evidence-based back pain guidelines, and the presence of sciatica reduces such compliance even further [Webster et al. 2005].
In sum, the treatment of sciatica remains problematic and evidence in support of optimal therapies for short- or long-term care seems inadequate. Much more extensive, high-quality research is needed; meanwhile, treatment of each patient remains an N-of-1 clinical trial for determining the best approach or combination of approaches for that individual.
> Jacobs WC, van Tulder M, Arts M, et al. Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review. Eur Spine J. 2011;20(4):513-522 [article here].
> Pinto RZ, Maher CG, Ferreira ML, et al. Epidural Corticosteroid Injections in the Management of Sciatica: A Systematic Review and Meta-analysis. Ann Intern Med. 2012(Nov 13); online ahead of print [abstract].
> Webster BS, Courtney TK, Huang YH, et al. Physicians' initial management of acute low back pain versus evidence-based guidelines. Influence of sciatica. J Gen Intern Med. 2005;20(12):1132-1135 [article here].
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