Cryotherapy is the local or general use of low temperatures in medical therapy. The term “cryotherapy” comes from the Greek cryo meaning cold, and therapy meaning cure. Cryotherapy has been used as early as the seventeenth century.
Cryotherapy is a pain treatment that uses a method of localized freezing temperatures to deaden an irritated nerve. Cryotherapy is also used as a method of treating localized areas of some cancers (called cryosurgery), such as prostate cancer and to treat abnormal skin cells by dermatologists. In this article we only discuss its use in nerve conditions.
In cryotherapy, a probe is inserted into the tissue next to the affected nerve. The temperature of the probe drops to then effectively freeze the nerve. The freezing inactivates the nerve and, as a result, painful nerve irritation is relieved. Cryotherapy is a relatively safe and effective means of treating localized nerve irritation. During cryotherapy, liquid nitrogen or argon gas flows into a needle-like applicator (a cryoprobe) creating intense cold that is placed in contact to diseased tissue. Physicians use image-guidance techniques such as ultrasound, computed tomography (CT) or magnetic resonance (MR) to help guide the cryoprobes to treatment sites located inside the body.
Cryotherapy has historically been used to provide pain relief, reduce fever, slow the damage of thermal burns, control bleeding, and prevent or reduce edema caused by soft tissue trauma. Cryotherapy has also been shown to be useful for the reduction of extrafusal and intrafusal muscle spasm, neuromuscular hypertonicity, and spasticity. Cryotherapy may additionally be used to elevate the pain threshold and slow destructive enzyme action that occurs in some joint diseases.
The cooling of bodily tissue is governed by two basic physiological principles –
- The cooling effect on the soft tissue by an ice massage or ice pack will decrease as the depth of the tissue increases.
- The time required for cooling to be effective will vary according to the type of tissue being cooled (the speed of cooling underlying tissues will decrease as the amount of insulating fat increases).
Uses of Cryotherapy
Cryotherapy can be applied topically (on the skin surface), percutaneously, or surgically. Topical cryotherapy is used typically in the case of skin and eye lesions. When the lesion is situated below the skin surface, a needle-like therapy probe or applicator needs to be placed through the skin. Occasionally, a surgical incision is required.
Cryotherapy is used to treat –
- Skin tumors.
- Pre-cancerous skin moles.
- Skin tags.
- Unsightly freckles.
- Retinoblastomas, a childhood cancer of the retina.
- Prostate, liver, and cervical cancers, especially if surgical resection is not possible.
Cryotherapy is also being used to treat tumors in other parts of the body, such as the kidneys, bones (including the spine), lungs, and breasts (including benign breast lumps called fibroadenomas). Although further research is needed to determine its long term effectiveness, cryotherapy has been shown to be effective in selected patients.
Side Effects
Cryotherapy risks include –
- Blisters and ulcers, leading to pain and infection
- Scarring, especially if the freezing was prolonged or deeper areas of the skin were affected
- Changes in skin color (skin turns white)
Components
- Liquid nitrogen – Cryotherapy using liquid nitrogen (temperature –196C) involves the use of a cryospray, cryoprobe or a cotton-tipped applicator. The nitrogen is applied to the skin lesion for a few seconds, depending on the desired diameter and depth of freeze. The treatment is repeated in some cases, once thawing has completed. This is known as a ‘double freeze-thaw’ and is usually reserved for skin cancers or resistant viral warts.
- Carbon dioxide snow – Carbon dioxide cryotherapy involves making a cylinder of frozen carbon dioxide snow (–78.5C) or a slush combined with acetone. It is applied directly to the skin lesion.
- DMEP – DMEP works at a temperature of –57C. It comes in an aerosol can available over the counter. It is used to treat warts using a foam applicator pushed onto the skin lesion for between 10 and 40 seconds, depending on its size and site.