Institution: | 1. Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 135-710, South Korea;2. Zein (ZEropaIN) Pain Treatment Clinic, 7 Seongbuk-Ro, Seongbuk-Gu, Seoul, 136-822, Republic of Korea |