Cryo surgery literally means ‘cold handiwork’. It makes use of local freezing for the controlled destruction or removal of living, but abnormal tissue. Mechanisms by which cryo surgery causes destruction of unwanted tissue are:
- Intracellular and extracellular ice formation causing mechanical damage to cells.
- Osmotic changes within the cells due to ice crystal formation that causes cell injury
- Thermal shock due to fall in the temperature of living cells.
- Denaturation of lipid protein complexes within the cell membranes.
- Vascular changes leading to necrosis of the tissue.
- Immunomodulation
The various refrigerants that can be used are:
- Ice
- Salt and ice
- Carbon dioxide snow
- Nitrous oxide
- Liquid nitrogen
- Freon
- Helium
Of these, CO2 snow and liquid nitrogen are routinely used by dermatologists. The cryogen is delivered through specialised devices.
Cryogun and Cryocan for storage of liquid nitrogen
A wide spectrum of skin conditions can be treated with cryo surgery. The most common ones are warts and molluscum contagiosum (viral infection), seborrhoic keratosis (benign tumor), moles (melanocytic nevi), developmental anomalies like hemangioma and lymphangioma, cysts, nodular cystic acne, acne scars, keloids, lentigines, basal cell carcinoma etc.
If done correctly with suitable freezing time, cryo surgery is an efficient, effective, simple and minimally painful procedure. Post treatment care should be taken to prevent secondary infections, scarring and pigmentation. Post inflammatory hyperpigmentation will improve over a period of 3-6 months.
Skin Lesions Before and After Cryotherapy
