Objective To compare a dual-freeze protocol with a triple-freeze protocol for pulmonary cryoablation in a porcine lung model.
Cryoablation with a dual-freeze (10-5-10-5, min) protocol and triple-freeze (5-5-5-5-10-5, min) protocol in normal lungs of 5 Tibet pigs was performed under an exposed operation field. Temperature changes of cryoprobes and diameter changes of iceballs were measured during the ablation, and then pathological changes of cryozones in lungs were reviewed 7 days after cryosurgery, and the surface and depth cryolesions were measured.
Result After two or three freeze-thaw cycles, different diameters on the iceball surface were formed, and seven days after cryosurgery, there were similar surface and depth cryolesions in the dual-freeze protocol and triple-freeze protocol. Pathologically, the triple freezing protocol was associated with a longer complete necrosis zone than the dual freezing protocol.
Conclusion Therefore, with the same freezing time, the triple-freeze protocol may become a more powerful lung-ablation method in cryosurgical application.
[Key words] Pulmonary cryoablation; Freeze protocols; Tibet pig model
Freeze Protocols.pdf