Transforaminal injection of corticosteroids for lumbar radiculopathy: systematic review and meta-analysis

Transforaminal epidural injection of steroids is used to treat lumbar radicular pain. However, there are only a few well-designed randomized, controlled studies on the effectiveness of steroid injection.

Hence, this study aims to assess the effectiveness of steroid injection to treat lumbar radicular pain using a meta-analysis of transforaminal epidural injection therapy for low back and lumbar radicular pain. The comparison was based on the mean difference in the Visual Analogue Score (VAS) and Oswestry Disability Index (ODI) from baseline to the specified followed up.

The available literature of lumbar transforaminal epidural injections in managing low back and radicular pain was reviewed. Data sources included relevant literature of the English language identified through searches of PubMed and EMBASE from 1966 to 2009, and manual searches of the bibliographies of known primary and review articles. Finally, the search included the Current Controlled Trials Register and the Cochrane Database of Controlled Trials.

The initial search identified 126 papers. After screening, five randomised controlled trials (RCTs) were studied for analysis and only three of these had followed-up patients systematically with pain and disability outcome scores to 3 months and of these, only one had follow up to 12 months. A total of 187 patients ('treatment group' receiving local anaesthetic/steroid injection) were compared with 181 patients ('control' group, receiving local anaesthetic only or saline injection). Improvement in pain (standardised mean difference in VAS 0.2 in favour of 'treatment'; 95%CI: -0.41 to 0.00, p = 0.05, I squared 0%) but not disability (standardised mean difference in ODI 0; 95%CI: -0.21 to 0.20, p = 0.99, I squared 0%) was observed between 'treatment' and 'control' groups; these differences were not significant. Additionally, the one study following patients to 12 months did not find any significant difference in VAS and ODI between treatment and control groups.

The current meta-analysis shows that transforaminal epidural steroid injections, when appropriately performed, should result in an improvement in pain, but not disability. The three RCTs that followed patients to 3 months (and the single study to 12 months) have found no benefit by the addition of steroids. The limitations of this study include the paucity of the available literature.