Often performed in the physician’s office, cryosurgery refers to the destruction of tissue by the application of extreme cold. The procedure is used to treat such dermatologic conditions as actinic and seborrheic keratoses, leukoplakia, molluscum contagiosum, condyloma acuminatum, verrucae and, sometimes, early basal cell epitheliomas and squamous cell carcinomas. It’s also used to treat gynecologic conditions, such as cervicitis, chronic cervical erosion, cervical polyps, and condyloma acuminata, as well as ophthalmic conditions, such as cataracts and retinal tears or holes.

Cryosurgery’s success depends on the type of lesion, the extent and depth of the freeze, and the duration between freezing and thawing. A slow thaw destroys lesions most effectively. Liquid nitrogen and nitrous oxide (N₂O) are the most commonly used cryogens. Carbon dioxide and freon are less frequently used. At -320° F (-196° C), liquid nitrogen is by far the most powerful cryogen. It’s especially useful for treating cancers, which resist cold well because of their vascularity. N₂O is often favored for less extensive procedures, since the surgeon can more easily control its effects.

More convenient versions, such as dimethylester propiane spray at -67° F (-55° C), are available for use in medical offices and clinics; however, use of these agents is restricted to warts and benign skin lesions, and their function is similar to that of N₂O models.