Histological research concerning cryotonsillectomy in dogs.

Resistance to freezing can be considered in connective tissue, blood vessels, and also epithelium and mature lymphocytes, but the tonsils are highly receptive to freezing, and thus during the 2 min two-cycle freezing the tonsils were able to be removed sufficiently. In addition, the edema in the peripheral tissue reached its peak in 12 to 24 hrs, and during this period it can be thought that dyspnoe could easily be induced. Histologically as well, necrosis was apparent after 12 hrs, with the peak coming during the first 3 days, and it was difficult to discern necrotic areas after 7 days. Revitalization of the epithelium, thrombosis, and fibrosis were also apparent as the 7th day. At the same time, dilated and regenerated capillary vellels were apparent. On the 14th day, collagen fibrosis of the deep layer tissue was found, and as of the 24-day collagen fibrosis up to the level of the epithelium was observed.