Effect of different cryosurgical protocols using liquid nitrogen on bone tissue: a histomorphological analyze

摘要

The aim of the present experimental study was to evaluate the morphological effects of different liquid nitrogencryosurgery protocols on bone tissue. The femoral diaphyses of 42 Wistar rats were exposed to three local andsequential applications of liquid nitrogen for 1 or 2 min, intercalated with periods of 5 min of passive thawing.The animals were sacrificed after 1, 2, 4 and 12 weeks and the specimens obtained were processed and analyzedhistomorphologically. Histologically, an increase in bone necrosis was observed for the two protocols in the secondweek after cryotherapy. A significant osteogenic phase was observed after 4 weeks. Moreover, complete remodelingprocess was encountered at the end of the morphological observation period (12 weeks), especially on oneminuteprotocol. Thus, this study indicated that the 2-min protocol produced more marked bone necrosis than the1-min protocol. In addition, the second experimental week was critical for bone necrosis with either cryotherapyprotocol. Further studies are important for the understanding of the long-term behavior of bone tissue after cryoapplicationof liquid nitrogen