1. Endosurgery Laboratory Kanehira, Kanazawa, Japan
2. Department of General Surgery, Tuebingen University, Tuebingen, Germany
3. Department of Surgery, Kouseiren Takaoka Hospital, Toyama, Japan
4. Surgical Business Department, Minimally Invasive Products Division, Olympus Optical Co., Ltd, Tokyo, Japan
5. Department of General and Cardia-thoracic Surgery, Kanazawa University, Kanazawa, Japan