1. Center for Diagnostic and Therapeutic Endoscopy, School of MedicineKeio University Tokyo Japan
2. Matsushima Clinic Coloproctology Center Matsushima Hospital Yokohama‐city Japan
3. Digestive Disease CenterShowa University Northern Yokohama Hospital Yokohama‐city Yokohama Japan
4. Ethicon Endo‐Surgery, Inc. Cincinnati USA