Cryosurgery is a non-invasive treatment for warts and verrucae using extreme cold. The treatment involves removing any surrounding hard skin and then marking the area to be treated with a pen. A probe is then selected dependent on the size of the wart or verruca to be treated. The probe is then attached to the nozzle of the flask containing the liquid nitrogen. When the trigger is depressed liquid nitrogen passes through the hollow probe and is evacuated via a rubber tube. Prior to depressing the trigger the probe is placed in contact with the wart or verruca. A gel is applied to the probe to maximise conductivity and contact.
The trigger is depressed and the wart or verrucea frozen for approximately 30 seconds. The treated area is then allowed to defrost or thaw. The probe is then reapplied for a further 30 seconds. A repeated freeze is effective because there is destruction in the thawing phase as well as the freezing phase.
Small verrucae and warts are particularly suited to treatment with cryosurgical probes.
Large verrucae and warts or larger areas of verrucae can be treated with a spray probe which is also applied to the nozzle of the flask.
In some cases a local analgesia can be administered prior to a cryosurgical treatment. This is often done prior to treating a large verruca or wart that requires prolonged freezing.
Other treatments can be used in conjunction with cryosurgery, for example, silver nitrate can be applied after the freezing process to reduce the possibility of blistering. Occlusal can also be used by the patient in addition to the cryosurgery.
After cryosurgical treatment has been administered an appointment is made for between two and four weeks for a review. Small warts or verrucae may resolve after one treatment but others which are larger or more resistant may require a number of cryosurgical treatments.