[Cryosurgical ablation of bone tissue with a newly developed miniature cryoprobe--adaptation of the method for use in bones in vitro and in vivo].

AIM Up to now, modern miniature cryoprobes have been used successfully for local destruction of soft tissue tumors without damaging adjacent healthy tissue. In this study, the methodology of cryoablation was applied to bone and the freezing effect as well as the cooling capacity of the probe was examined in vivo and in vitro. METHODS Freezing was performed by cooling one or two probes, with a diameter of 3.2 mm to -180 degrees C with liquid nitrogen. The cooling capacity of the probes was determined under thermic control by an in vitro measurement on human bone, followed by an in vivo measurement on femoral and tibia bones of a sheep. RESULTS The in vitro freezings achieved a sufficient tissue cooling using one or two cryoprobes. The simultaneous use of 2 probes resulted in a synergistic effect between the probes. According to the body heat, the registered temperature curves, during the in vivo freezings, showed a more flat trend. Nevertheless, temperatures below -50 degrees C were achieved at a distance of 1 cm from the probe due to the synergistic effect. Local or systematical intraoperative complications have not been observed. CONCLUSION An adequate tissue cooling of bone matrix can be achieved within in vivo freezings through the use of one or more miniature cryoprobes so that the use of this probe could possibly become an alternative or supplement to the surgical resection of pathologic bone processes.