1. Department of Gastroenterological Surgery, Toho University School of Medicine, Tokyo 143-8541, Japan
2. Department of Clinical Oncology, Toho University Graduate School of Medicine, Tokyo 143-8541, Japan
3. Port Square Kashiwado Clinic, Kashiwado Memorial Foundation, Chiba 260-0025, Japan
4. Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan