Macroscopic Analysis of the Effect of Different Protocols of Liquid Nitrogen Application to the Buccal Mucuous of Mice

Abstract

The present study evaluated the effects of the use of liquid nitrogen cryosurgery. It proposed, as a model of study, a macroscopic analysis of three different protocols for the application of liquid nitrogen to the buccal mucuous of mice: (1) by means of a closed system (i.e., a probe); (2) by means of an open system (i.e., a spray); and (3) by means of prefabricated stems with cotton tips. Two freezes, of twenty seconds each, separated by five minutes of thaw were used. The death of the animals was accomplished after six hours of the end of the experiments. The initial and final data relating to the length and width each of the animal's tongues was recorded, analyzed, and compared to the data concerning the other test animals' tongues. In the spray group the edema was great and all througth the tongue, reaching larger distances away from the application point. This was accompanied by significant evidence that this protocol is difficult to control. The application of liquid nitrogen by means of probe resulted in tissue damage that was more localized. Also, while there was an anatomical deformation due to the edema provoked in the tongue as a result of the probe means of application, this was lower than that observed in the spray group. The alterations provoked by the application of the liquid nitrogen with cotton stems were milder, and restricted to the central area of the cryogenic agent application. It was concluded that a spray should not be used to apply liquid nitrogen in the buccal cavity. Instead, the use of stems with cotton tips is the technique best recommended, of the three, for it allows the most control of the damage