Cryosurgery is a surgical technique that uses extreme cold to destroy diseased or damaged tissue. It is used where cutting or heat would pose a further danger to the health of the patient. It is commonly used to remove skin lesions, moles, hemmorhoids and parasitic cysts.
Cryosurgery usually uses liquid nitrogen, which is sprayed on the tissue, circulated through a tube, or even daubed on the affected tissue. In some cases, a mixture of solid carbon dioxide mixed with acetone is used. Over-the-counter preparations, used for conditions such as wart or skin tag removal use a mixture of dimethyl ether and propane.
Cryosurgery has several benefits. It is usually less painful to the patient than cutting would be. It is minimally invasive for the treatment of external conditions as the skin doesn't have to be pierced. It also leaves less of a scar. It is also much cheaper than alternatives.
However, cryosurgery is not without risks. Damage to surrounding tissues, including nerves, is a common complication.
In the episode Hunting, cryosurgery is used to remove parasitic cysts as these would burst and release the parasite into the bloodstream if punctured with a scalpel. The extreme cold kills the parasite without risk of rupturing the cyst.