1. Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino, Tokyo 180-8602, Japan
2. Azabu University Veterinary Teaching Hospital, Soft Tissue and Tumor Surgery, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan
3. Division of Veterinary Anatomy, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino, Tokyo 180-8602, Japan