Efficacy of Epidural Injections in Managing Chronic Spinal Pain: A Best Evidence Synthesis

Abstract

Background: Epidural injections have been used since 1901 in managing low back pain and sciatica. Spinal pain, disability, health, and economic impact continue to increase, despite numerous modalities of interventions available in managing chronic spinal pain. Thus far, systematic reviews performed to assess the efficacy of epidural injections in managing chronic spinal pain have yielded conflicting results. Objective: To evaluate and update the clinical utility of the efficacy of epidural injections in managing chronic spinal pain. Study Design: A systematic review of randomized controlled trials of epidural injections in managing chronic spinal pain. Methods: In this systematic review, randomized trials with a placebo control or an active-control design were included. The outcome measures were pain relief and functional status improvement. The quality of each individual article was assessed by Cochrane review criteria, as well as the Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB). Best evidence synthesis was conducted based on the qualitative level of evidence (Level I to V). Data sources included relevant literature identified through searches of PubMed for a period starting in 1966 through August 2015; Cochrane reviews; and manual searches of the bibliographies of known primary and review articles. Results: A total of 52 trials met inclusion criteria. Meta-analysis was not feasible. The evidence in managing lumbar disc herniation or radiculitis is Level II for long-term improvement either with caudal, interlaminar, or transforaminal epidural injections with no significant difference among the approaches. The evidence is Level II for long-term management of cervical disc herniation with interlaminar epidural injections. The evidence is Level II to III in managing thoracic disc herniation with an interlaminar approach. The evidence is Level II for caudal and lumbar interlaminar epidural injections with Level III evidence for lumbar transforaminal epidural injections for lumbar spinal stenosis. The evidence is Level II for cervical spinal stenosis management with an interlaminar approach The evidence is Level II for axial or discogenic pain without facet arthropathy or disc herniation treated with caudal or lumbar interlaminar injections in the lumbar region; whereas it is Level II in the cervical region treated with cervical interlaminar epidural injections. The evidence for post lumbar surgery syndrome is Level II with caudal epidural injections and for post cervical surgery syndrome it is Level II with cervical interlaminar epidural injections. Limitations: Even though this is a large systematic review with inclusion of a large number of randomized controlled trials, the paucity of high quality randomized trials literature continues to confound the evidence. Conclusion: This systematic review, with an assessment of the quality of manuscripts and outcome parameters, shows the efficacy of epidural injections in managing a multitude of chronic spinal conditions. Key words: Chronic pain, spinal pain, epidural injections, local anesthetic, steroids, interlaminar epidural injections, caudal epidural injections, transforaminal epidural injections