With a boiling point of -195.8 Celsius, liquid nitrogen is the cryogen of choice for treating benign and malignant neoplasms.
Melanocytes and fibroblasts are the cells that are most and least sensitive to the destructive effects of cryosurgery.
Tumors that require histopathology for diagnosis and recurrent nonmelanoma skin cancers are contraindications for treatment with cryosurgery.
Several cryosurgery techniques exist to treat benign and malignant neoplasms.
Electrosurgery can be categorized into electrofulguration, electrodessication, electrocoagulation, electrosection, electrocautery, and electrolysis (Table 206-4).
Electrosurgical devices have a low risk of interfering with cardiac and non cardiac implanted electronic devices (IEDs).
Perioperative and intraoperative safety considerations should be made when performing electrosurgery on patients with IEDs.
Curettage and electrodessication is an acceptable definitive treatment for malignant tumors.
Cryosurgery refers to the use of extreme cold to destroy cells of abnormal or diseased tissue. The earliest use of a cold refrigerant in medicine is attributed to White, a New York dermatologist, in 1899.1,2 Using a cotton-tipped applicator dipped into liquefied air, he successfully treated warts, nevi, and precancerous and cancerous lesions. In 1907, Whitehouse, another New York dermatologist, reported the use of the spray method in the cryosurgical treatment of skin cancers.3
Cryobiology refers to the study of the effects of subzero temperature on living systems. Tissue destruction from cryotherapy results from direct cell injury, vascular stasis, and the local inflammatory response.
Freezing cells convert water to ice (crystallization). Rapid freezing causes intracellular ice crystal formation with the disruption of electrolytes and pH changes, whereas slow freezing causes extracellular ice formation and less cell damage. Therefore, tissue effects and cell death are most readily achieved when tissue is frozen rapidly.4
During thawing, recrystallization occurs when ice crystals fuse to form large crystals that disrupt cell membranes. As the ice melts further, the extracellular environment becomes hypotonic, causing water to infuse into cells and cause cell lysis.5 The longer the thawing time, the greater the damage to cells because of increased solute effect and greater recrystallization.
After freezing, stasis within the vasculature occurs. This loss of circulation and resultant anoxia is a major mechanism of injury from cryosurgery. As the tissue thaws at temperatures higher than 0°C (32°F), a brief hyperemic response ensues with resultant edema and inflammation.5
Table 206-1 lists targets of cryosurgery with associated cell death temperatures. Melanocytes are the most sensitive to cryosurgery, with cell destruction at temperatures of −4°C to −7°C (24.8°F to 19.4°F).6 As a result, depigmentation may occur, especially in darkly pigmented individuals. Keratinocytes require longer freezing to temperatures of −20°C to −30°C (−4°F to −22°F) until cell death and are more resistant to cooling effects. Fibroblasts are the most resistant to freezing and do not undergo cell death ...