作者单位:Max-Planck-Institut fur Festkorperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany[1]Department of Operative Techniques and Surgical Research, Institute of Surgery, University of Debrecen, Medical and Health Science Center, H-4032 Debrecen, Nagyerdei krt. 98, Hungary. imiko@dote.hu[2]