1. Pain Clinic, Bundang CHA General Hospital, College of Medicine, Pochon CHA University, Seongnam, Korea.
2. Department of Anesthesiology and Pain Medicine, Bundang CHA General Hospital, College of Medicine, Pochon CHA University, Seongnam, Korea.
3. Department of Anesthesiology and Pain Medicine, Wonkwang University Sanbon Medical Center, School of Medicine, Wonkwang University, Gunpo, Korea.