Transforaminal Versus Interlaminar Approaches to Epidural Steroid Injections: A Systematic Review of Comparative Studies for Lumbosacral Radicular Pain

Abstract

Background: The superiority of transforaminal epidural steroid injections (TFESI) vs. interlaminar epidural steroid injections (ILESI) for treating unilateral lumbosacral radicular pain (LSRP) is unproven. Objective: To assess studies comparing TFESI to ILESI for unilateral LSRP for pain relief and functional improvement. Study Design: Systematic review of comparative studies. Methods: A systematic literature search was conducted using the Cochrane Central Register of Controlled Trials, PubMed, and Scopus databases for trials reported in English. Studies meeting the Cochrane Review criteria for randomized trials and the AHCQ criteria for observational studies were included. Evidence was graded using the USPSTF classification. Results: Five (prospective) and 3 (retrospective) studies were included assessing 506 patients. Statistical analysis was calculated only utilizing the 5 prospective studies and consisted of 249 patients with an average of 3.2 months follow-up. In the short-term (2 weeks), there was a 15% difference favoring TFESI vs. ILESI for pain relief. There was no efficacy difference at one or 6 months. Combined pain improvements in all 5 prospective studies revealed < 20% difference between TFESI and ILESI (54.1% vs. 42.7%). There was slightly better functional improvement in ILESI groups (56.4%) vs. TFESI groups (49.4%) at 2 weeks. Combined data showed slight differences (TFESI 40.1% and ILESI 44.8%). Limitations: The limitations of this systematic review include the relative paucity of comparative studies. Conclusions: The findings show that both TFESI and ILESI are effective in reducing pain and improving functional scores in unilateral LSRP. In the treatment of pain, TFESI demonstrated non-clinically significant superiority to ILESI only at the 2-week follow-up. Based on 2 studies, ILESI demonstrated non-clinically significant superiority to TFESI in functional improvement. Key words: Radiculopathy, epidural steroids, transforaminal, interlaminar, systematic review