Cryoablation

Cryoablation is a treatment that uses intense cold to freeze and destroy abnormal areas of tissue. To freeze the tissue, several hollow probes are placed through the skin into the area needing treatment. Imaging such as ultrasound and CT scanning, is used to make sure the probes are placed in the correct position.

A machine pumps a mixture of gases (argon and helium) into the probe and back out again. The gases stay inside the probe and do not come into direct contact with the tissue. The gases make the tips of the probes very cold – around minus 100°C – and then thaws or warms them up again. The cold only travels a few centimetres from the tip of the probe – the normal tissue further away is not affected.

Evidence shows that freezing and thawing tissue in this way causes the cells to break down and the tissue can be destroyed. The abnormal area then shrinks and forms scar tissue. For some conditions, this is an easier way to get rid of abnormal tissue than surgery.

At Great Ormond Street Hospital (GOSH), cryoablation is carried out in the Interventional Radiology (IR) department.

Some conditions are caused by an area of abnormal tissue in the muscles, fat or bone which can cause problems such as pain or swelling. Often this abnormal tissue can be removed by an operation, or sometimes medicines can be used to shrink it or make it less troublesome. However, some conditions do not respond to these treatments, so different techniques are needed.

Cryoablation and other similar techniques have been developed to treat some kinds of cancer, bone conditions and disease affecting the soft tissues or muscle. For some conditions, it is now the preferred method of treatment because it is a minimally invasive procedure and does not involve complex surgery, long stays in hospital or surgical scars.

Your child’s doctors think that cryoablation is the best treatment for your child’s condition. They will discuss the reasons for this recommendation with you in more detail in clinic.

Your child needs to be fasted for the procedure for the general anaesthetic.

If your child takes regular medication, please speak to your child’s team about when to stop these before the procedure.

As a general rule:

Food and milk:

• Breast-fed babies - can have their last feed thre hours before the procedure. Breast milk is digested faster than solid food or formula.
• Bottle-fed babies and children- can have their last milk feed, food or milk drink, six hours before the procedure. They should not have any food or milk after this time.

Water:

• All babies and children can have a drink of water (but no other fluids), until one hour before the procedure.

Please follow these instructions carefully, otherwise your child’s procedure may be delayed or even cancelled.

You will already have received information about how to prepare your child for the procedure in your admission letter. You may need to come to GOSH before the cryoablation procedure so that your child can have a pre-admission assessment to check that they are well enough. This appointment may involve taking blood samples and other tests.

Your child will need to be admitted to a bed on a ward in the hospital. The person bringing your child to the procedure should have “parental responsibility” for them. Parental responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have parental responsibility, we may have to cancel the procedure.

An anaesthetist will visit to talk to you about your child’s anaesthetic. The specialist will explain the procedure in more detail, discuss any questions you may have and ask you to sign a consent form giving permission for your child to have the procedure. If your child has any medical problems, please tell the specialists. Contrast dye which shows up well on X-rays is used during the procedure and is removed from the body through urination (peeing), so please tell the doctors if your child has any kidney problems.

Many of the procedures we perform involve the use of X-rays. Legally, we are obliged to ask anyone over the age of 12 whether there is any chance they might be pregnant, and we will also ask for the first date of their last period (if started). This is to protect babies in the womb from receiving unnecessary radiation.

You and your child will then be brought to the Interventional Radiology (IR) suite for the procedure to be done.

Once your child is under general anaesthetic, the radiologist will confirm the exact position of the area that needs to be treated using ultrasound and the CT scanner. They may need to give your child an injection of contrast through a vein to give detailed CT or ultrasound pictures of the area. The doctor will clean the skin and insert two or more of the probes into the area to be treated through very small cuts in the skin. The position of the needles will be checked using X-rays.

The doctors will then generate several cycles of freezing and thawing to the area via the probes. The area being treated is closely monitored with X-rays or CT to make sure that only the abnormal area is treated and to avoid affecting any normal structures such as blood vessels or nerves close by.

Generally, the ablation itself will take 60 to 90 minutes but on occasion it may take longer. Once finished, the team will cover the treated area with a small plaster.

Your child will be having the procedure under general anaesthetic. Every anaesthetic carries a risk, but this is extremely small.

The risks of cryoablation include:

• Post-ablation syndrome, which occurs in about one in four patients. This is a flu-like illness that happens three to five days after treatment and lasts for a few days at most.
• Bleeding from the needle insertion site.
• Injury to normal structures near to the area that is treated. This includes damage to nearby blood vessels, nerves and overlying skin. The doctors may use some strategies to minimize these risks such as warming the skin during the procedure.

The procedure does involve the use of X-rays. The levels that are used are low dose and therefore low risk. If you have any concerns regarding the use of radiation, please discuss this with the person performing your procedure beforehand.

This will depend on the exact condition that your child has. Alternatives usually include a surgical operation, injection treatment such as sclerotherapy or a drug treatment. There are also other ablation treatments like radiofrequency ablation that your doctor may discuss with you.

Your child will return to the ward after they have recovered from the general anaesthetic if they have had one. Some children feel sick and vomit after a general anaesthetic. Your child may have a headache or sore throat or feel dizzy, but these side effects are usually short- lived and not severe. Your child can start eating and drinking as normal once they feel like it.

The area that has been treated may be tender and uncomfortable for a few days. Usually, regular pain relief such as paracetamol or ibuprofen taken according to the instructions on the package is enough to deal with any pain.

Your doctors may want your child to stay in hospital overnight so they can make sure they are comfortable before going home. They will let you know about this before your child’s admission. Some children can go home on the same day. Your doctors will advise you about weight bearing, exercise and return to school when they talk to you after the procedure.

You should call the hospital if:

• The area looks red, swollen and feels hotter than the surrounding skin.
• The skin over the treated area becomes blistered or breaks down.
• Your child is in a lot of pain and pain relief does not seem to help.
• Your child has a temperature of 38 degrees or higher.

You can contact the ward by calling the GOSH switchboard on 020 7405 9200 and asking for the ward your child was discharged from.

If you are unable to get through, please call NHS111 by dialling 111.

Written by: Interventional Radiology

Reference number: 0226PAT0043

Last reviewed: February 2026

Next review due: February 2030