At present, in orthopedic surgery, the reconstruction of bone defects following resection of malignant tumors is effected by several methods. The irradiation and autoclaving of bone segments are the 2 methods of choice to extracorporeally devitalize the resected tumor-bearing bone segments. An alternative, gentle method of devitalizing bone-associated cells by exposing normal and tumor cells to extracorporeal high hydrostatic pressure (HHP) has been introduced. The aim of this study was to examine the ex vivo effect of HHP on the cell growth of normal and tumor-afflicted freshly-resected small human bone segments. For this, tumor-afflicted human bone segments of 5 x 5 x 5 mm in size, obtained during surgery from 14 patients suffering from chondrosarcoma or osteosarcoma, in comparison to bone segments obtained from 36 patients with normal bone, disease were exposed to HHP levels of 0, 150 and 300 MPa for 10 min at 37 degrees C. Following HHP-treatment, the specimens were placed into cell culture and observed for cell outgrowth up to 50 days. In control samples (0 MPa), rapid outgrowth of cells was observed. HHP-treatment of 150 MPa however, resulted in reduced outgrowth of cells from these bone specimens; at 300 MPa, no outgrowth of cells was detected. Light microscopy and standard histological examination showed morphological changes between control samples (0 MPa) and 150 MPa. Our results suggest that the treatment of tumor-afflicted bone and the associated cartilage by HHP leads to the devitalization of bone cells concomitant with complete impairment of cellular outgrowth, a precondition for re-implantation of the HHP-treated bone.