Liquid Nitrogen - Benefits and uses of Liquid Nitrogen in Surgery and Treatment of Skin

Feeling that necrosis produces less scarring, cryosurgery by liquid nitrogen - 196°C has become a good tool in the practice of dermatology. Easily available, the technique is easy to perform and post-operative wound care is simple. Useful in patients allergic to local anesthesia and people who are afraid of surgery. Less popular is cryosurgery by nitrous oxide and CO2 snow.

Mode of action used in liquid nitrigen

• There is cell death following cryosurgery.
• Tissue water is changed to ice which leads to cell dehydration.
• Freezing of small blood vessel leads to ischaemic changes in the tissue whic ends in cell necrosis.

Tissue Sensitivity :

Depth of freeze: Controlled by rate of flow and the distance of the spray unit from the lesion and the time of contact. Development of freezing (circle) and then thawing help to decide the duration of exposure.

Equipments used while performing liquid nitrogen surgery

1. Storage tank/cylinder

2. Cotton swab

3. Cryo-probes

4. Spray unit

5. Thermocouple devices

Indications of liquid nitrogen

Complications in liquid nitrogen

Most important is depigmentation and scar formation which is seen more frequently. Post-operative oedema, bullous formation and a throbbing sensation may be seen.

Important tips in liquid nitrogen:

• Select your patient, explain the procedure to the patient and tell him/her about transient pain and possible complications.
• Select your equipment carefully (a spray unit or a cotton tip).
• Note and control your rate of flow from the spray unit, check the time of freezing and adjust the distance from the lesion. This all helps in better controlling of the depth of freeze which is seen as lateral spread of the freeze on the surface.
• Malignant lesions should be carefully monitored and a close F/U is done to insure complete destruction. Avoid excessive freezing. Better underdo rather than overdoing and later regretting.