EFFECT OF MODERATE BONE HYPERTHERMIA ON CELL VIABILITY AND MECHANICALFUNCTION

Extracorporeal hyperthermia treatment of bone followed by its reimplan tation may be an optional treatment of bone tumors. In this study, the authors examined the minimal hyperthermic condition in which complete eradication of all viable cells in rat bone can be achieved and the m echanical effect of this treatment on the tested bone. When the result s were evaluated histologically by special lactate dehydrogenase activ ity staining, it was found that complete bone cell death occurred afte r 30 minutes of heating at 60 degrees C, Cartilage cells, including th ose of the epiphysis, were more resistant to thermal damage, When the ability of the specimens to proliferate in cell cultures was tested, n o growth was observed after heating at temperatures of 50 degrees C or greater. The mechanical stiffness tested in the Instron machine showe d decreased bone stiffness at 70 degrees C but no change in the breaki ng load of the bones. Controlled hyperthermia's ability to eradicate v iable cells without significant damage to the mechanical properties ma y have clinical relevance in limb salvage tumor surgery.