Cryotherapy

Cryosurgery involves local freezing of tissues for their controlled destruction or removal. Here we will discuss the role of cryosurgery in skin diseases. The various cryogens used are Nitrous oxide (-75°C), Carbon-dioxide snow (-79°C) and liquid Nitrogen (-196°C). We will discuss two cryosurgical techniques that the author uses in her dermatosurgical practice. Liquid nitrogen has a temperature of -196 °C and freezes tissues to -40 to -60 °C.

• LIQUID NITROGEN CRYOSURGERY

• CRYOSLUSH WITH CARBON DIOXIDE ICE

• CRYO-PEEL WITH LIQUID NITROGEN

What are the indications of liquid nitrogen cryosurgery?

There are numerous indications but to enumerate a few :
• warts, molluscum contagiosum, pyogenic granuloma, skin tags, seborrhoeic warts, milia, cystic acne, acne scars and keloids.
• Precancreous conditions like leukoplakias, Bowen's disease, actinic keratosis.
• Cancers of the skin which are very small and have no deep or distant spread

When should liquid nitrogen cryosurgery not be done?

It should not be preformed in immuno-suppressed conditions like certain cancers, patients on immunosuppressive drugs, people allergic to cold temperatures, people having vasospastic disorders and cold intolerance.

What happens during the treatment?

The procedure involves spraying liquid nitrogen over the diseased part leading to freezing of the tissues. This causes a stinging sensation and numbness initially. Later on there may be varying degree of pain which may need analgesics or elevation of the part.

What happens after spraying?

After a few hours of spraying the area shows colour changes due to controlled destruction. The part may become dark or red and swollen. A blister is formed which later turns into an eschar, thus the desired tissue is destroyed. The blister should not be disturbed as it prevents infection. The sprayed part takes 1 to 3 weeks to heal. Multiple sessions of cryosurgery may be required till the desired result is achieved.

What are the advantages?

• no anaesthesia is required.

• no hospitalization is necessary.

• multiple lesions can be treated at the same time.

• good for small local cancer recurrences.

• it is a no touch technique, hence beneficial while treating HIV Positive cases.

Are there any complications?

Hyperpigmentation, hypertrophic scars, milia may be a few transient problems. Hypopigmentation, scarring could be the long term consequences