The outcome of epidural injections in lumbar radiculopathy is not dependent on the presence of disc herniation on MRI: assessment of short-term and long-term efficacy.

Abstract Objective Lumbar radiculopathy is a condition with major physical, social and economic consequences. Despite its favourable prognosis the burden can be significant. In this study, we aimed to determine the value of MRI and the efficacy of transforaminal epidural injections (TEI) in patients with lumbar radiculopathy secondary to lumbar disc herniation (LDH) and other causes (non-LDH). Methods Patients with lumbar radiculopathy were reviewed for radiological diagnosis based on MRI. For patients receiving TEI therapy, response after 6-8 weeks (short term) and 16 weeks (long term), number of injections, subsequent surgery and eventual patient outcome were evaluated. Treatment response was assessed by patient-reported symptom relief and NRS pain scores. Results Overall, 66% of MRI examinations demonstrated a clinically relevant LDH. 486 out of 1824 patients received TEI of which one-third did not demonstrate LDH. 70% of patients reported a short-term effect with significant pain reduction and 44% reported a long-term effect. No significant differences were observed between the LDH and non-LDH groups. 59% of patients required multiple injections, and eventually reported similar efficacy compared to patients treated with a single injection. Conclusions A considerable part of MRI examinations in patients with lumbar radiculopathy does not demonstrate a clinically relevant LDH. Regardless of the radiological diagnosis the majority of patients treated with TEI benefits on both short and long term after a single or multiple injections regime. Subsequent injections are advisable if the effect from the first injection is unsatisfactory or wears off. MRI examination before TEI therapy may be redundant which allows for expedition of this treatment.