Effects of transforaminal, interlaminar, and caudal epidural injections for herniated lumbar disc: a network meta-analysis

Epidural injection (EI) is a commonly utilized intervention for managing lower back and radicular leg pain stemming from a herniated lumbar disc (HLD). Three primary EI techniques are currently employed: transforaminal (TFEI), interlaminar (ILEI), and caudal epidural injections (CEI). This network meta-analysis (NMA) aimed to assess the relative effectiveness of TFEI, ILEI, and CEI in alleviating pain and enhancing function among patients with HLD. PubMed, Embase, Cochrane Library, Web of Science were comprehensively searched from inception to January 9, 2026 for randomized controlled trials (RCTs). Studies that compared different EI techniques for patients with HLD were included in this NMA. Weighted mean differences (WMDs) in Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) score changes were calculated for short-term and long-term evaluations. The NMA was performed using R software with gemtc package. Treatment hierarchy was evaluated using the Surface Under the Cumulative Ranking Curve (SUCRA) probabilities. The Confidence in Network Meta-Analysis (CINeMA) framework was applied to evaluate the certainty of evidence. Ten RCTs involving 902 patients were included. The NMA revealed that no statistically significant differences among the three EI techniques for any outcomes ( P > 0.05). However, SUCRA-based probability ranking analysis indicated that TFEI had the highest likelihood of being the most effective treatment for pain reduction and functional improvement across both short- and long-term assessment periods. The certainty of evidence for all comparisons across all outcomes ranged from low to very low, indicating limited confidence in the effect estimates. Although probability rankings based on SUCRA values suggested that TFEI might be the preferred intervention, the NMA revealed no statistically significant differences among TFEI, ILEI, and CEI in reducing pain or improving function. Critically, the certainty of evidence was rated as low to very low across all comparisons. Current findings do not support the superiority of any one injection approach over the others and are insufficient to guide clinical decision-making.