1. Laboratory of Small Animal Surgery, Department of Veterinary MedicineAzabu University Fuchinobe, Chuoku Sagamihara Kanagawa Japan
2. Veterinary Teaching Hospital, Graduate School of Veterinary MedicineHokkaido University Kita‐ku Sapporo Hokkaido Japan
3. Veterinary Medical Center, Graduate School of Life and Environmental SciencesOsaka Prefecture University Rinku‐oraikita Izumisano Osaka Japan
4. Department of Small Animal Clinical Sciences, School of Veterinary MedicineRakuno Gakuen University Bunkyodai‐Midorimachi Ebetsu Hokkaido Japan
5. Division of Small Animal Surgery, Cooperative Department of Veterinary Medicine, Faculty of AgricultureIwate University Ueda Morioka Iwate Japan