Comparison of Radiation Exposure during Fluoroscopy-Guided Transforaminal Epidural Steroid Injections at Different Vertebral Levels

OBJECTIVE: To estimate and compare radiation exposure during transforaminal fluoroscopy-guided epidural steroid injection (TFESI) at different vertebral levels. MATERIALS AND METHODS: Fluoroscopy-guided TFESI was performed in 181 patients. The patients were categorized into three groups according to the injected lumbosacral nerve level of L2-4, L5, or S1. Fluoroscopy time (FT) and dose area product (DAP) were recorded for all patients; correlations between FT and DAP were determined at each level, and both FT and DAP were compared between the different vertebral levels. RESULTS: The numbers of patients who received ESI at L2-4, L5, and S1 were 29, 123, and 29. Mean FT was 44 seconds at L2-4, 33.5 seconds at L5, and 37.7 seconds at S1. Mean DAP was 138.6 µGy·m(2) at L2-4, 100.6 µGy·m(2) at L5, and 72.1 µGy·m(2) at S1. FT and DAP were positively correlated in each group (p values < 0.001). FT was significantly shorter at L5 than that at L2-4 (p = 0.004) but was not significantly different between S1 and L2-4 or L5 (p values = 0.286 and 0.532, respectively). DAP was significantly smaller at L5 and S1 than that at L2-4, but L5 and S1 were not significantly different. After correcting for FT, DAP was significantly smaller at S1 than that at either L2-4 or L5 (p values = 0.001 and 0.010). CONCLUSION: The radiation dose was small during a single procedure of ESI and showed differences between different lumbosacral spine levels.