The effectiveness of lumbar interlaminar epidural injections in managing chronic low back and lower extremity pain.

BACKGROUND
Intervertebral disc herniation, spinal stenosis, intervertebral disc degeneration without disc herniation, and post lumbar surgery syndrome are the most common diagnoses of chronic persistent low back and lower extremity symptoms, resulting in significant economic, societal, and health care impact. Epidural injections are one of the most commonly performed interventions in the United States in managing chronic low back pain. However the evidence is highly variable among different techniques utilized - namely interlaminar, caudal, and transforaminal - and for various conditions, namely - intervertebral disc herniation, spinal stenosis, and discogenic pain without disc herniation or radiculitis. Multiple systematic reviews conducted in the evaluation of the effectiveness of interlaminar epidural injections have been marred with controversy. Consequently, the debate continues with regards to the effectiveness, indications, and medical necessity of interlaminar epidural injections.


STUDY DESIGN
A systematic review of lumbar interlaminar epidural injections with or without steroids.


OBJECTIVE
To evaluate the effect of lumbar interlaminar epidural injections with or without steroids in managing various types of chronic low back and lower extremity pain emanating as a result of disc herniation or radiculitis, spinal stenosis, and chronic discogenic pain.


METHODS
The available literature on lumbar interlaminar 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 observational studies. The level of evidence was classified as good, fair, or limited 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 were improvement in functional status, psychological status, return to work, and reduction in opioid intake.


RESULTS
Overall, 82 lumbar interlaminar trials were identified. All non-randomized studies without fluoroscopy and randomized trials not meeting the inclusion criteria were excluded. Overall, 15 randomized trials and 11 non-randomized studies were included in the analysis. Analysis was derived mainly from fluoroscopically-guided randomized trials and non-randomized studies. The evidence is good for radiculitis secondary to disc herniation with local anesthetics and steroids, fair with local anesthetic only; whereas it is fair for radiculitis secondary to spinal stenosis with local anesthetic and steroids, and fair for axial pain without disc herniation with local anesthetic with or without steroids, with fluoroscopically-guided epidural injections.


LIMITATIONS
The limitations of this study include that we were unable to perform meta-analysis for disc herniation, and the paucity of evidence for discogenic pain and spinal stenosis. Further, methodological criteria have been highly variable along with sample sizes. The studies were heterogenous.


CONCLUSION
The evidence based on this systematic review is good for lumbar epidural injections under fluoroscopy for radiculitis secondary to disc herniation with local anesthetic and steroids, fair with local anesthetic only; whereas it is fair for radiculitis secondary to spinal stenosis with local anesthetic and steroids, and fair for axial pain without disc herniation with local anesthetic with or without steroids.