1. Division of Gastroenterological Surgery, Department of Surgery, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
2. Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
3. Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan