In varicosclerotherapy according to Sigg, the sclerosing agent is applied to the standing patient. The bulging varicose vein is punctured, a few drops of blood are drained to check the strictly intravascular position of the injection needle. Then, with the needle in place, the patient is transferred to the back with the leg elevated at an angle of 30°. A half-empty 2ml syringe is placed on the cannula. The 1ml of air is first injected into the vein (Airblock technique), followed by the injection agent (1ml), which can now suddenly come into contact with the vein wall. After injection of the sclerosing agent, a compression bandage is applied. It is important to ensure that the sclerosed area is additionally compressed with a foam pallet.
The advantage of this method is that, in the case of extravasation, the air from the syringe first reaches the tissue. This can be clinically well verified. Thus, the risk of injection-induced necrosis is considered to be low.