Comparison of Clinical Efficacy of Epidural Injection With or Without Steroid in Lumbosacral Disc Herniation: A Systematic Review and Meta-analysis.

Background: Epidural injection is performed for treatment of back and radicular pain in patients with lumbosacral disc herniation (LDH). Steroids are usually administered to effectively remove inflammatory mediators, and local anesthetics or saline also contribute to pain reduction by washing out chemical mediators or blocking the nociceptor activity. Controversy exists regarding whether steroids produce superior clinical effects compared with local anesthetics or saline.

Objectives: This study investigated whether epidural injection of steroids produces better clinical effects than local anesthetics or saline in the treatment of LDH.

Study Design: A literature search was performed in MEDLINE, EMBASE, Cochrane review, and KoreaMed for studies published from January 1996 until July 2017. From among the studies fulfilling the search criteria, those that compared the clinical efficacy of steroids and control agents, such as local anesthetics or saline, in terms of pain control and functional improvement were included in this study. Exclusion criteria included a previous history of lumbosacral surgery, non-specific low back pain, severe spinal stenosis, and severe disc degeneration.

Setting: A systematic review and meta-analysis using a random effects model on randomized controlled studies (RCTs).

Methods: After reviewing titles, abstracts, and full texts of 6,711 studies that were chosen following removal of duplicates after the initial database search, 15 randomized controlled studies were included in our qualitative synthesis. Data including pain score, functional score, and follow-up period were extracted from 14 studies and analyzed using a random effects model to calculate the effect size and its corresponding statistical significance. Quality and level of evidence were established in accordance with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

Results: Steroids and local anesthetics were shown to be effective. Steroid showed significantly better pain control than control agents at 1 month, 3 months, and 6 months. The superiority of steroid in pain control was more prominent at one month, but diminished from 3 months to 1 year, showing no significant superiority in terms of mean difference, With respect to functional score, no significant difference was observed between steroids and control agents. The subgroup analysis showed that steroid revealed significant superiority in pain and functional score at 1 month to saline rather than local anesthetics. Generally, the quality of included studies was evaluated as high-grade, but the evidence level was determined to be moderate, due to inconsistencies.

Limitation: Analyses of safety or adverse effects could not be performed due to a lack of available data from the included studies.

Conclusions: Steroid is recommended over local anesthetics or saline for pain control in patients with LDH, with a weak strength of recommendation. The superiority of steroids was remarkable, especially at relatively short-term follow-ups, and maintained until the 1 year follow-up. The clinical benefits of steroids at 1 month were more prominent when compared with saline, than when compared with local anesthetics.

Key Words: Steroid, local anesthetics, saline, epidural injection, pain, function, meta-analysis, systemic review.