Particle steroid drug such as triamcinolone has been used widely for epidural steroid injection (ESI) treatment in Korea. However, Korea FDA recently prohibit ESI using triamcinolone, following the regulation of US FDA. Therefore, dexamethasone and betamethasone become only candidate drugs for ESI in Korea and the investigators are curious about the effectiveness and safety of both drugs due to limitation of information about comparison of two drugs in previous literature. So, this study aims to compare the effectiveness and safety of both drugs and our hypothesis is that there is no difference of the effectiveness between dexamethasone and betamethasone at 2 weeks after ESI.