Predictive factors of efficacy of periradicular corticosteroid injections for lumbar radiculopathy.

BACKGROUND AND PURPOSE Steroid periradicular infiltration is a common nonsurgical sciatic pain treatment of inconsistent efficacy. The purpose of this study was to identify factors for predicting the efficacy or failure of this procedure. METHODS Two hundred twenty-nine patients with lumbar radiculopathy were prospectively followed up at 2 weeks and 1 year after percutaneous periradicular steroid infiltration. The intensity of radicular pain was scored on the visual analog scale (VAS). Pain relief was classified as "excellent" when the pain was completely resolved or had diminished by 75% or more, "good" for a diminution of 50% to 74%, "fair" for a diminution of 25% to 49%, or "poor" for a diminution of less than 25% or an increase in pain. RESULTS The mean VAS scores were 6.5 (range, 3.1-9.5) before and 4.2 (range, 0-9.5) 2 weeks after the procedure. Pain relief was graded as excellent in 45 patients (19.7%), good in 48 patients (21%), fair in 45 patients (19.7%), and poor in 91 patients (39.7%). Cause of pain, conflict location, and pain intensity were not predictive factors of radicular pain relief, whereas the symptom duration before the procedure was highly correlated with the pain relief outcome. Patients with excellent results 2 weeks after the procedure had a mean duration of symptoms of 3.04 months (SD 3.28) versus 7.96 months (DS 9.04) in the group with poor pain relief. CONCLUSIONS Periradicular infiltration is a simple, safe, and effective nonsurgical procedure that should be performed quite early in the course of the illness to provide radicular pain relief, because corticosteroid infiltration is less beneficial for patients with more chronic radicular pain.