A vein with leaky valves no longer contributes to the return of blood to the heart – it merely causes blood to pool. If it is closed off, healthy deeper veins take over this task. Radiofrequency ablation and sclerotherapy are based on this principle: both switch off the diseased vein instead of stripping it out.
In radiofrequency ablation, a thin catheter is advanced into the trunk vein under ultrasound guidance. Its tip emits high-frequency energy and heats the vein wall, which shrinks and seals as a result. Over the following months, the body breaks down the closed vein. Technically, the method is closely related to laser treatment.
Sclerotherapy, sometimes called injection treatment, needs no catheter. A sclerosing agent is delivered into the vein through a fine needle and deliberately irritates its inner wall. The vein seals and turns into a thin cord, which the body gradually dissolves. For spider veins and small veins, the agent is injected as a liquid; for larger side branches, usually as a foam under ultrasound control.
Which method is suitable depends on the findings. Straight trunk veins are suited to radiofrequency or laser treatment; side branches, residual veins after previous procedures and spider veins to sclerotherapy. The two are often combined – first the source of the backflow, then the visible branches.