Dog - Cryotherapy (Cryosurgery)

What is cryosurgery?

Cryosurgery is sophisticated frostbite. Natural, severe frostbite will affect the blood supply particularly to extremities, such as ears, fingers and toes. This will result in death of the part which is subsequently lost.

Cryosurgery, (cryotherapy) employs the same principal. Cryotherapy is a better description of the procedure since surgery is usually associated with cutting and in this case the treatment (therapy) does not, with a few exceptions, involve actual cutting.

Cryotherapy has been around for about a hundred years. The technique is not new. The principles are that the application of intense cold will result in the death of the target tissue and the numbing of surrounding sensory nerves so that pain and discomfort are reduced. In man this aspect is often employed for the treatment of patients with intractable cancer to reduce pain and discomfort by temporarily numbing sensory nerves. In animals the technique is employed to treat tumours where conventional surgery would be difficult or impossible, e.g. some tumours of the mouth, or where the analgesic/anaesthetic properties of the technique would be useful. Examples include the removal of highly irritant tumours or lesions which the animal is constantly biting, licking or scratching. Tumours or infected itchy lesions in elderly patients considered unsuitable for general anaesthesia and prolonged surgical techniques where a long anaesthetic may present unacceptable risks are good candidates for this technique.

Why sophisticated frostbite?

It is sophisticated frostbite because a source of cold, for example liquid nitrogen with a boiling point of approximately -180°C, or sometimes warmer cryogens like dry ice (carbon dioxide) or nitrous oxide, are used via sophisticated apparatus to deliver the source of cold to the target tissue and at the same time to spare surrounding tissue.

Is the technique painful?

Anyone who has been frost bitten will confirm that the actual freezing insult is painful. Think how painful it is when your fingers get cold in winter yet snow and ice are relatively 'warm' cryogens! After all, cold fingers do not usually result in frostbite. With cryotherapy the actual freezing insult, which could be painful, is always carried out under anaesthesia. This may be either a local anaesthetic with sedation or more usually a general anaesthetic. Because of the inherent analgesic/anaesthetic effect of the procedure, if subsequent freezing sessions are necessary, these can sometimes take place without the use of any further anaesthetics and are painless.

The intense cold kills bacteria and other germs. The technique is often used for the treatment of anal furunculosis, a condition affecting the anal region of some dogs particularly German Shepherd dogs.

Once freezing has occurred the tissue slowly dies and falls away. In some sites such as the mouth and the anus the tissue may liquefy and look green and gangrenous. Usually all that is necessary is gentle bathing of the area to remove as much of the dead and sloughing tissue as possible. There is sometimes a smell. However despite the appearance there is no discomfort because of the temporary anaesthetic effect on nerve endings. The patient is usually very much happier than before. In cases where there is the need for extensive tissue destruction sometimes more than one session is necessary.

Cryosurgery is also used in veterinary ophthalmology for a variety of conditions including eyelashes which sometimes grow in the wrong direction and rub on the eye, or lashes which grow in an extra row along the eyelid. It is also used for the treatment of certain types of glaucoma (increased pressure inside the eye) and the removal of subluxated or luxated lenses.

If you are at all concerned do not hesitate to telephone for advice.

Is it curative?

In many cases it can be curative depending on the condition and the site. Anal furunculosis lesions respond in about 80% of cases.

When used for the removal of aberrant or extra eyelashes (distichiasis) it is almost invariably curative although other lashes may grow.

Small warts and small skin tumours are usually cured with just one cryo session.

Tumours in the mouth often also go into remission after one freezing and cause no further trouble.

Is it beneficial?

Because of the anaesthetic effect your pet will benefit from the technique if the lesion causes discomfort even if a cure is not possible. There is also some scientific evidence that when used in the treatment of anal furunculosis it can stimulate an immune response.