Epidural Corticosteroid Injections for Sciatica

An Abridged Cochrane Systematic Review and Meta-Analysis

Crystian B. Oliveira, PhD; Christopher G. Maher, PhD; Manuela L. Ferreira, PhD; Mark J. Hancock, PhD; Vinicius Cunha Oliveira, PhD; Andrew J. McLachlan, PhD; Bart W. Koes, PhD; Paulo H. Ferreira, PhD; Steven P. Cohen, MD; Rafael Z. Pinto, PhD

Disclosures

Spine. 2020;45(21):E1405-E1415. 

In This Article

Abstract and Introduction

Abstract

Study Design: Systematic with meta-analysis

Objectives: The aim of this study was to investigate the efficacy and safety of epidural corticosteroid injections compared with placebo injection in reducing leg pain and disability in patients with sciatica.

Summary of Background Data: Conservative treatments, including pharmacological and nonpharmacological treatments, are typically the first treatment options for sciatica but the evidence to support their use is limited. The overall quality of evidence found by previous systematic reviews varies between moderate and high, which suggests that future trials may change the conclusions. New placebo-controlled randomized trials have been published recently which highlights the importance of an updated systematic review.

Methods: The searches were performed without language restrictions in the following databases from 2012 to 25 September 2019: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, PubMed, Embase, CINAHL, PsycINFO, International Pharmaceutical Abstracts, and trial registers. We included placebo-controlled randomized trials investigating epidural corticosteroid injections in patients with sciatica. The primary outcomes were leg pain intensity and disability. The secondary outcomes were adverse events, overall pain, and back pain intensity. We grouped similar trials according to outcome measures and their respective follow-up time points. Short-term follow-up (>2 weeks but ≤3 months) was considered the primary follow-up time point due to the expected mechanism of action of epidural corticosteroid injection. Weighted mean differences (MDs) and risk ratios (RRs) with their respective 95% confidence intervals (CIs) were estimated. We assessed the overall quality of evidence using the GRADE approach and conducted the analyses using random effects.

Results: We included 25 clinical trials (from 29 publications) providing data for a total of 2470 participants with sciatica, an increase of six trials when compared to the previous review. Epidural corticosteroid injections were probably more effective than placebo in reducing short-term leg pain (MD −4.93, 95% CI −8.77 to −1.09 on a 0–100 scale), short-term disability (MD −4.18, 95% CI: −6.04 to −2.17 on a 0–100 scale) and may be slightly more effective in reducing short-term overall pain (MD −9.35, 95% CI −14.05 to −4.65 on a 0–100 scale). There were mostly minor adverse events (i.e., without hospitalization) after epidural corticosteroid injections and placebo injections without difference between groups (RR 1.14, 95% CI: 0.91–1.42). The quality of evidence was at best moderate mostly due to problems with trial design and inconsistency.

Conclusion: A review of 25 placebo-controlled trials provides moderate-quality evidence that epidural corticosteroid injections are effective, although the effects are small and short-term. There is uncertainty on safety due to very low-quality evidence.

Level of Evidence: 1

Introduction

Sciatica is a condition characterized by radiating leg pain caused by inflammation or irritation of a spinal nerve root.[1] Although a variety of terms have been used to describe this condition (e.g., lumbosacral radicular pain or radicular leg pain), the term sciatica is commonly used by patients and clinicians. Estimates for the 1-year prevalence of sciatica vary greatly ranging from 3%[2] to 14%[3] mostly due to variation on how sciatica is defined across studies. Sciatica is characterized by radiating leg pain below the knee in a dermatomal distribution, or at least one neurological finding (e.g., myotomal weakness, reflex changes, dermatomal sensory deficit).[1,4] Although patients with acute sciatica typically have a favorable prognosis,[1,4] a substantial proportion of these patients still experience pain in the long term.[5] In comparison with patients with low back pain alone, patients with sciatica usually report higher disability and pain intensity[6] as well as higher rates of work absence.[7,8]

Conservative treatments, including pharmacological and nonpharmacological treatments, are typically the first treatment options for sciatica, but the evidence to support their use is limited.[9–11] Epidural injection of a corticosteroid is a more invasive treatment option that delivers corticosteroids in the epidural space aiming to reduce the local inflammatory process.[12,13] The use of epidural injections for treating sciatica is common and increasing. For example in the United States, a total of 2,032,959 epidural corticosteroid injections were performed in 2016,[14] representing an increase of 8.6% compared with 2009.[14]

Previous systematic reviews investigated the effects of epidural corticosteroid injections compared with placebo injection in patients with sciatica.[15–18] However, the overall quality of evidence found by these systematic reviews varies between moderate and high which suggest that future trials may change the conclusions. In addition, the risk of adverse events is not well discussed in these reviews. New placebo-controlled randomized trials have been published recently which highlights the importance of an updated systematic review. Therefore, the objective of this Cochrane review was to investigate the efficacy and safety of epidural corticosteroid injections compared with placebo injection in patients with sciatica.

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