The 1-Year Results of Lumbar Transforaminal Epidural Steroid Injection in Patients with Chronic Unilateral Radicular Pain: The Relation to MRI Findings and Clinical Features

OBJECTIVE: In patients with chronic radicular pain, we aimed to evaluate subgroup differences in 1-yr response to transforaminal epidural steroid injection. DESIGN: In this longitudinal cohort study of 100 subjects, 170 transforaminal epidural steroid injections were performed for 1 yr. The sample was stratified by type of disc herniation (protrusion n = 57, extrusion n = 27), by location of disc herniation (central/subarticular n = 60, foraminal n = 24), by grade of nerve root compression (low-grade compression n = 61, high-grade subarticular nerve compression n = 14, high-grade foraminal nerve compression n = 25), and by positive Slump test (n = 67). Treatment response was evaluated by visual analogue scale leg pain and self-reported disability (Oswestry Disability Index). Logistic regression was used to analyze the predictive value of baseline characteristics including the stratified subgroups. RESULTS: High-grade subarticular nerve compression predicted the 1-yr improvement in both visual analogue scale leg pain (P = 0.046) and Oswestry Disability Index (P = 0.027). Low age (P < 0.001), short duration of leg pain (P = 0.015), and central/subarticular disc herniation (P = 0.017) predicted improvement in Oswestry Disability Index. CONCLUSIONS: In patients treated with one or several transforaminal epidural steroid injections due to chronic lumbar radicular pain, clinical findings failed to predict the 1-yr treatment response. Low age, short duration of leg pain, central/subarticular disc herniation, and high-grade subarticular nerve compression predicted a favorable 1-yr response to transforaminal epidural steroid injection. (Less)