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the use of extreme cold (usually liquid nitrogen) to destroy unwanted tissue (warts or cataracts or skin cancers)

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低温(凍結)外科療法(組織の破壊などに極度の低温を用いる療法)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/12/12 09:33:08」(JST)

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Cryosurgery (cryotherapy) is the use of extreme cold in surgery to destroy abnormal or diseased tissue.^[1] The term comes from the Greek words cryo (κρύο) ("icy cold") and surgery (cheirourgiki – χειρουργική) meaning "hand work" or "handiwork". Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions.^[2]

Uses

Warts, moles, skin tags, solar keratoses, Morton's neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer, prostate cancer, lung cancer, oral cancers, cervical disorders and, more commonly in the past, hemorrhoids. Soft tissue conditions such as plantar fasciitis (Jogger's heel) and fibroma(benign excrescence of connective tissue) can be treated with cryosurgery. Generally, all tumors that can be reached by the cryoprobes used during an operation are treatable. Although found to be effective, this method of treatment is only appropriate for use against localized disease, and solid tumors larger than 1 cm. Tiny, diffuse metastases that often coincide with cancers are usually not affected by cryotherapy.

Cryosurgery works by taking advantage of the destructive force of freezing temperatures on cells. When their temperature sinks beyond a certain level ice crystals begin forming inside the cells and, because of their lower density, eventually tear apart those cells. Further harm to malignant growth will result once the blood vessels supplying the affected tissue begin to freeze.

Method

Liquid nitrogen

Cryogun used to spray liquid nitrogen

A common method of freezing lesions is using liquid nitrogen as the cooling solution. The super-cooled liquid may be sprayed on the diseased tissue, circulated through a tube called a cryoprobe, or simply dabbed on with a cotton or foam swab.

Carbon dioxide

Less frequently, doctors use carbon dioxide "snow" formed into a cylinder or mixed with acetone to form a slush that is applied directly to the treated tissue.

Argon

Recent advances in technology have allowed for the use of argon gas to drive ice formation using a principle known as the Joule-Thomson effect. This gives physicians excellent control of the ice, and minimizing complications using ultra-thin 17 gauge cryoneedles.

Dimethyl ether – propane

A mixture of dimethyl ether and propane is used in some preparations such as Dr. Scholl's Freeze Away. The mixture is stored in an aerosol spray type container at room temperature and drops to −41 °C (−42 °F) when dispensed. The mixture is often dispensed into a straw with a cotton-tipped swab.

Products

Cryosurgical Systems

A number of medical supply companies have developed cryogen delivery systems for cryosurgery. Most are based on the use of liquid nitrogen, although some employ the use of proprietary mixtures of gases that combine to form the cryogen. Some commonly used cryosurgical products are:

Brymill
Cry-Ac
Cryoalfa
CryoPen
CryoProbe
Cryosurgery, Inc. Verruca-Freeze
Histofreezer
Miltex Cryosolutions
Premier CryOmega
Premier NitroSpray
Myoscience Iovera

Results

Cryosurgery is a minimally invasive procedure, and is often preferred to more traditional kinds of surgery because of its minimal pain, scarring, and cost; however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to nerve tissue is of particular concern.

Patients undergoing cryosurgery usually experience redness and minor-to-moderate localized pain, which most of the time can be alleviated sufficiently by oral administration of mild analgesics such as Ibuprofen, codeine, tramadol or acetaminophen (paracetamol). Blisters may form as a result of cryosurgery, but these usually scab over and peel away within a few days.

References

^ DermNet NZ – Cryotherapy
^ eMedicine.com – Dermatology – Cryotherapy

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English Journal

Effect of iron oxide nanoparticles on the permeability properties of Sf21 cells.

Wang J1, Zhao G2, Shu Z3, Zhou P4, Cao Y4, Gao D5.
Cryobiology.Cryobiology.2016 Feb;72(1):21-6. doi: 10.1016/j.cryobiol.2015.12.002. Epub 2015 Dec 17.
It was recently reported that nanoparticles could significantly modulate the thermal properties of solutions at subzero temperatures, and as a result, nanoparticles have been widely used in both cryopreservation and cryosurgery. In cryopreservation, the water permeability coefficient of cell membran
PMID 26705894

A new method for temperature-field reconstruction during ultrasound-monitored cryosurgery using potential-field analogy.

Thaokar C1, Rossi MR1, Rabin Y2.
Cryobiology.Cryobiology.2016 Feb;72(1):69-77. doi: 10.1016/j.cryobiol.2015.10.153. Epub 2015 Nov 14.
The current study aims at developing computational tools in order to gain information about the thermal history in areas invisible to ultrasound imaging during cryosurgery. This invisibility results from the high absorption rate of the ultrasound energy by the frozen region, which leads to an appare
PMID 26586098

The role of cryosurgery in the treatment of the incompetent great saphenous vein.

Balint R1, Vizsy L, Farics A, Balint IB.
International angiology : a journal of the International Union of Angiology.Int Angiol.2016 Feb;35(1):78-83. Epub 2015 Feb 12.
Our aim was to determine the place of cryosurgery in the treatment of the incompetence of the great saphenous vein. Primary end-point of this study was to evaluate the clinical effectiveness of cryostripping and cryosclerosis. Complications frequently related to saphenous vein stripping were analyze
PMID 25673310