1. Department of General, Visceral and Transplantation SurgeryUniversity of HeidelbergHeidelberg Germany
2. Department of General, Visceral, Endocrine and Transplantation SurgeryCantonal Hospital St. Gallen Switzerland
3. Institute of Medical Biometry and InformaticsUniversity of HeidelbergHeidelberg Germany
4. Department of SurgeryLukas HospitalNeuss Germany