Caudal epidural injections in the management of chronic low back pain: A systematic appraisal of the literature

Background: Epidural injections with local anesthetics and steroids are one of the most commonly used interventions in managing chronic low back pain and lower extremity pain of various causes. However, despite their extensive use, debate continues on their effectiveness due to the lack of well-designed, randomized, controlled studies to determine the effectiveness of epidural injections in general, and caudal epidural injections in particular. Study Design: A systematic review of caudal epidural injections with or without steroids in managing chronic pain secondary to lumbar disc herniation or radiculitis, post lumbar laminectomy syndrome, spinal stenosis, and discogenic pain without disc herniation or radiculitis. Objective: To evaluate the effect of caudal epidural injections with or without steroids in managing various types of chronic low back pain with or without lower extremity pain emanating as a result of disc herniation or radiculitis, post lumbar laminectomy syndrome, spinal stenosis, and chronic discogenic pain. Methods: The available literature on caudal epidural injections with or without steroids in managing various types of chronic low back pain with or without lower extremity pain was reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials and the criteria developed by the Newcastle-Ottawa Scale criteria for fluoroscopic observational studies. The level of evidence was classified as good, fair, or poor based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to December 2011, and manual searches of the bibliographies of known primary and review articles. Outcome Measures: The primary outcome measure was pain relief (short-term relief = up to 6 months and long-term > 6 months). Secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake were utilized. Results: For this systematic review, 73 studies were identified. Of these, 51 were excluded and a total of 16 studies met inclusion criteria for methodological quality assessment with 11 randomized trials and 5 nonrandomized studies. For lumbar disc herniation, the evidence is good for short- and long-term relief of chronic pain secondary to disc herniation or radiculitis with local anesthetic and steroids and fair relief with local anesthetic only. In managing chronic axial or discogenic pain, spinal stenosis, and post surgery syndrome, the indicated evidence is fair. Limitations: The limitations of this study include the paucity of literature, specifically for chronic pain without disc herniation. Conclusion: There was good evidence for short- and long-term relief of chronic pain secondary to disc herniation or radiculitis with local anesthetic and steroids and fair relief with local anesthetic only. Further, this systematic review also provided indicated evidence of fair for caudal epidural injections in managing chronic axial or discogenic pain, spinal stenosis, and post surgery syndrome.