Role of Magnetic Resonance Imaging in Ascertaining the Success of Transforaminal Epidural Steroid Injection for Lumbar Radicular Pain

Objective: To explore the outcome differences of lumbar transforaminal epidural steroid injection (TFESI) according to magnetic resonance imaging (MRI) findings in patients with lumbar radicular pain. Design: Retrospective study. Setting: Single university-based interventional pain management unit. Patients: Fifty-nine patients who had lumbar radicular pain with a recent lumbar MRI and three-month follow-up were included. Methods: MRI findings were reviewed for the following items: herniation type (bulging, protrusion, extrusion), herniation location (central, subarticular, foraminal, extraforaminal), high intensity zone (HIZ), and nerve root impingement (NRI). Pain severity was evaluated using a visual analogue scale (VAS) at time of before injection, then two weeks and three months after. Results: Pain scores improved significantly in each group ( P < 0.05) at all time points, but there were no statistically significant differences in improvements according to type or location of disc herniation. Pain scores were significantly lower in patients with HIZ at the second week and in patients with NRI at the third month ( P < 0.05). Conclusions: TFESI was an effective treatment method in patients with radicular pain, irrespective of the type or location of disc herniation. However, greater improvement in pain may be expected at the second week in patients with HIZ and at the third month in patients with NRI.