The cryosurgical ablation of bone tissue by means of a new miniature cryoprobe - Adaptation of the method for an in-vitro- and in-vivo-application tobone.

Aim: Up to now, modem miniature cryoprobes have been used successfully for local destruction of soft tissue tumors without damaging adjacent healthy t issue. In this study, the methodology of cryoablation was applied to bone a nd the freezing effect as well as the cooling capacity of the probe was exa mined in vivo and in vitro. Method: Freezing was performed by cooling one o r two probes, with a diameter of 3.2 mm to -180 degreesC with liquid nitrog en. The cooling capacity of the probes was determined under thermic control by an in vitro measurement on human bone, followed by an in vivo measureme nt on femoral and tibia bones of a sheep. Results: The in vitro freezings a chieved a suffizient tissue cooling using one or two cryoprobes. The simult aneous 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 fiat trend. Nevertheless, temperatures bel ow - 50 degreesC were achieved at a distance of 1 cm from the probe due to the synergistic effect. Local or systemical intraoperative complications ha ve 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 mi niature cryoprobes so that the use of this probe could possibly become an a lternative or supplement to the surgical resection of pathologic bone proce sses.