Pregabalin, an anticonvulsant is widely used for treatment of neuropathic pain. Recently, it was reported that premedication of pregabalin before general anesthesia is effective to reduce postoperative pain. Up to date, there is no study about the effect of premedication of pregabalin on the spinal anesthesia. Therefore, in this study, investigators investigate the effect of premedication of pregabalin on the spinal anesthesia.