Cryosurgery (with cryo from the Ancient Greek κρύο ) is the use of extreme cold in surgery to destroy abnormal or diseased tissue;
Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions.
History
In 1841, English physician James Arnott described therapeutic applications of extremely cold temperatures, namely a mixture of crushed ice and salt applied locally (to skin or
mucous membrane). He theorized his technique was capable of "arresting the accompanying inflammation, and perhaps destroying the vitality of the cancer cell."
His works were the first to hypothesize that extreme cold could be used to selectively damage or destroy harmful tissue.
Uses
, moles,
,
solar keratosis, molluscum,
Morton's neuroma
and small
are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer,
prostate cancer, lung cancer, oral cancers,
Cervix 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.
Cryosurgery works by taking advantage of the destructive force of freezing temperatures on cells. When their temperature sinks beyond a certain level 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 supplying the affected tissue begin to freeze.
Cryosurgery is used to treat a variety of benign skin including:
Cryosurgery may also be used to treat low risk skin cancers such as basal cell carcinoma and squamous cell carcinoma but a biopsy should be obtained first to confirm the diagnosis, determine the depth of invasion and characterize other high risk histologic features.
Method
Liquid nitrogen
A common method of freezing lesions is by using
liquid nitrogen as the cryogen. The liquid nitrogen may be applied to lesions using a variety of methods, such as dipping a cotton or synthetic material tipped applicator in liquid nitrogen and then directly applying the cryogen onto the lesion.
The liquid nitrogen can also be sprayed onto the lesion using a spray canister. The spray canister may utilize a variety of nozzles for different spray patterns.
A cryoprobe, which is a metal applicator that has been cooled using liquid nitrogen, can also be directly applied onto lesions.
Carbon dioxide
Carbon dioxide is also available as a spray and is used to treat a variety of benign spots. 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 minimizes complications using ultra-thin 17 gauge cryoneedles.
Freeze sprays
A mixture of
dimethyl ether and
propane is used in some "
freeze spray" preparations such as Dr. Scholl's Freeze Away. The mixture is stored in an
aerosol spray type container at room temperature and drops to when dispensed. The mixture is often dispensed into a straw with a cotton-tipped swab. Similar products may use tetrafluoroethane or other substances.
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.
In cancer treatment
Cryosurgery is also used to treat internal and external tumors as well as tumors in the bone. To cure internal tumors, a hollow instrument called a cryoprobe is used, which is placed in contact with the tumor. Liquid
nitrogen or
argon gas is passed through the cryoprobe.
Ultrasound or
MRI is used to guide the cryoprobe and monitor the freezing of the cells. This helps in limiting damage to adjacent healthy tissues. A ball of ice crystals forms around the probe which results in freezing of nearby cells. When it is required to deliver gas to various parts of the tumor, more than one probe is used. After cryosurgery, the frozen tissue is either naturally absorbed by the body in the case of internal tumors, or it dissolves and forms a scab for external tumors.
Results
Cryosurgery is a minimally invasive procedure, and is often preferred to other types of surgery because of its safety, ease of use, minimal pain and scarring as well as low cost;
however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to
Nerve is of particular concern but is rare.
Cryosurgery cannot be used on lesions that would subsequently require biopsy as the technique destroys tissue and precludes the use of histopathology.
More common complications of cryosurgery include blistering and edema which are transient.
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 or acetaminophen (paracetamol). may form as a result of cryosurgery, but these usually scab over and peel away within a few days.
See also
