Small cryotherapy devices for the treatment of skin warts.

ABSTRACT

STUDY PURPOSE: Effectiveness of cryotherapy on skin wart models. MATERIALS AND METHODS: Two small cryotherapy devices, Wartner and Wortie, were administered for 10″-60″ on tomatoes and potatoes used as skin wart models. Frozen surface and depth were evaluated by standardized photography and computer analysis. Tissue temperature at depths of 0.1-10 mm was assessed by an electronic thermometer during treatment. RESULTS: Cryotherapy induced a transient freezing of the tomato surface. The devices produced similar tomato tissue temperature reduction at all depths examined. At 5 mm, Wortie induced lower tissue temperatures than Wartner. Both devices induced potato tissue destruction to a depth of 0.5-1.2 mm at 40″ and 50″. Wartner induced a maximum destruction at 40″, Wortie led to a partially linear destruction depth with freezing time. The devices produced similar reduction of potato tissue temperature at all depths tested. Wartner induced more rapidly lower temperatures (1.5 mm, 10″, p = .001). Wortie induced lower tissue temperatures with time (0.1 mm, 50″, p = .025; 60″, p = .039; 5 mm, 60″, p = .05). None of the devices reached the lethal temperature of -22 °C. CONCLUSIONS: Both cryotherapy devices produced sufficient tissue damage, at least in the potatoes, to a depth of 0.5-1.2 mm when applied for 40″ (commercially proposed time).