How ultrasound guided foam sclerotherapy (UGFS) is performed
There are many different ways that ultrasound guided foam sclerotherapy (UGFS) can be performed and so this description is a general outline of a technique that I have found to be optimal.
Firstly the patient is scanned by the Clinical Vascular Scientist with a duplex ultrasound scanner to identify which veins need to be treated and which are the ideal entry points. The patients are given information about the pros and cons of the procedure, and in particular the after-care which entails wearing the bandages and stockings for 14 days and nights for the optimal result.
Under aseptic conditions, the professional performing the injections then mixes up the foam ready for injection. This is often performed using the Tessari method although other techniques have been described and invented. In essence, one unit of the liquid sclerosant is put into one syringe. In the second syringe, four units of gas are prepared to be mixed with the first syringe. This gas should always be either carbon dioxide or a mixture of carbon dioxide and oxygen. Air should not be used because of the risk of nitrogen in the air travelling through the heart to the brain.
The two syringes are linked together usually through a three-way tap but other devices have been used to connect the two syringes.
The Clinical Vascular Scientist identifies the vein to be treated and the process can then start.
The two syringes are then compressed in turn, mixing the gas with the sclerosant and making a foam. Usually the mixing takes about 10 passages after which the foam is pushed into one of the two syringes ready for use.
- Foam sclerotherapy is injected into selected veins under ultrasound guidance
- Ultrasound probe
The syringe is removed from the three-way tap and a sterile needle is placed on the end of the syringe. This is introduced directly under the ultrasound probe, showing the vein and guiding the needle into the vein to be treated. Once there, the foam can be injected and this is easily seen on ultrasound as a white substance.
- Foam sclerotherapy spreading through selected veins. Foam displaces the blood to have maximum effect on the vein wall
- Ultrasound probe guided the foam sclerotherapy injection
Immediately on completion of the injection, the leg is elevated and the leg is bound, crushing the vein walls together and stopping blood from flowing back into the treated section of vein. Occasionally two or three veins can be treated at one level before the binding is positioned.
An alternative method favoured by some is to place plastic tubes or “cannulae” into the veins to be treated under ultrasound control and then taping these into position. This then allows the phlebologist to inject foam into each in turn and then bind the leg immediately after the injections.
Once the procedure has been performed, the bandage is covered by a graduated pressure stocking and the patient is allowed home after 20 minutes, provided no visual disturbance has occurred.
The patient is told to remove all of the bandages after two weeks (14 days and nights) but to wear the stockings for a further two weeks. After four weeks the patient returns and any areas where thrombus has formed are relieved by pinprick under ultrasound guidance – often referred to as “removing trapped blood”.
As with all sclerotherapy, the results are not seen for three months after the initial injections.