Intralesional cryosurgery. A new technique using cryoneedles.

A new method for applying cryosurgery in depth has been performed in a trial in order to achieve more effectiveness and avoid many of the disadvantages of conventional techniques. A needle is introduced into the skin from one point and runs through the deeper tissues of the lesion, appearing at the surface on the opposite border. A cryogen is then passed through one end of the needle and vents to the atmosphere from the opposite end. An ice cylinder is formed around the embedded part of the needle within the deeper tissues. The distance of extension of freezing can be estimated by insertion of thermocouple needles as well as by the degree of extension of the whitish ice balls formed around the points of contact between the skin surface and the visible portions of the needle. New varieties of needles have been developed to facilitate improved efficacy in achieving better depth of freeze. The needles are angled, curved, and hook-shaped. Some are partially insulated to better localize the direction of freezing. The process was very practical, and effectively eradicated 85% of epidermal lesions after one freeze; 15% needed additional sessions as did deeper dermal lesions.