1. Department of Gastroenterological Surgery; Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences; 2-5-1 Shikata-cho, Kita-ku Okayama 700-8558 Japan
2. Department of Anesthesiology; Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences; Okayama Japan
3. Department of Human Morphology; Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences; Okayama Japan