1. Department of Rehabilitation Medicine, Chungbuk National University Hospital, Cheongju, Republic of Korea
2. Department of Rehabilitation Medicine, Chungbuk National University College of Medicine, Cheongju, Republic of Korea
3. Department of Thoracic and Cardiovascular Surgery, Chungbuk National University Hospital, Cheongju, Republic of Korea
4. Department of Thoracic and Cardiovascular Surgery, Chungbuk National University College of Medicine, Cheongju, Republic of Korea.