Emerging Concepts In Cryosurgery For Wart Treatment
- Volume 21 - Issue 11 - November 2008
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In order for cryosurgery to be effective, tissue temperatures must change rapidly (by 50 to 100°C per minute) with a baseline tissue cell temperature of -20°C or lower. Cell death occurs below -20°C. One must hold the temperature at these levels for a specified period of time depending on the type of lesion and its anatomical location. This extreme temperature allows intracellular changes to occur and adequate cell destruction to take place.
During the state of freeze, ice crystals form within the cells and cause a transient membrane osmotic gradient. This alteration causes rupture of the membranes and associated organelles. Initially, there is a decrease in vascular flow followed by a rapid vascular flow after thawing. After the initial freeze, the treated area takes on a white, even snow-like appearance due to the ice in the tissue.
This so-called ice ball then thaws and an inflow of blood presents as an area of erythema. Blister formation occurs and this is followed by drainage. A crust usually forms after blister destruction and, depending on the size, location and depth of the freeze, healing may take one to six weeks. Be advised that certain areas may become hypopigmented.
Based on the location of the warts, application times for cryosurgery will vary. For example, the plantar surface of the foot has a much thicker epidermal layer than the dorsal or digital areas. Consequently, in my experience, I found that a 90-second application is required on the plantar surface and 45- to 60-second applications are required for thinner skinned areas.
The various cryosurgery modalities have different temperature ranges (see “A Quick Guide To Temperatures Of Cryosurgery Modalities” at left). One must select the correct modality and temperature to provide a safe and successful treatment. Modalities with more extreme temperature ranges may cause damage to tissue structures, potentially causing nerve and connective tissue pathology. The cold temperatures are produced by the specific modality and are not the actual temperatures on the surface of the skin.
Can A New Cryosurgery Pen Facilitate Successful
The CryoPen System (CryoPen) is an all-in-one unit consisting of the cooling chamber, six probes with varying application diameters, a probe thermometer and reusable tips. One can remove a probe from the cooling chamber and immediately replace it with another probe of the same type so the next application will always be ready.
Over the past two years, physicians in our office have used the CryoPen System to treat hundreds of patients with verruca. These patient presentations ranged from a singular lesion to mosaic warts, both unilateral and bilateral. The patient population included children, teenagers and adults. The general reception has been more than satisfactory. However, certain patients experienced uncomfortable responses to the cold. No matter what form of modality one uses, certain patients will react less than satisfactorily.
There are certain advantages with the CryoPen System. It enables me to provide a treatment plan to patients without the need for injections or postoperative wound care. In addition, patients can get the treated areas wet.
A Guide To Using The CryoPen
First, evaluate the patient’s verruca. Surgical debridement of all hyperkeratotic tissue is essential to try to visualize capillary endings without causing capillary bleeding. If bleeding occurs, apply a hemostatic agent first.
Select the appropriate size CryoPen probe and verify the temperature. Apply a sterile tip to the probe and insert the probe, selecting the appropriate contact time. With the help of an assistant, one can treat a variety of lesions in different areas using multiple probes at the same time.