Radiofrequency Ablation (VNUS) is a relatively new thermal ablation technique that uses a specially developed proprietary RF catheter placed inside the vein. A cut down, stab incision with vein exteriorization, or a Seldinger over-the-wire technique is used to place an introducer sheath into the truncal varix to be ablated. A special RF ablation catheter is passed through he sheath and along the vein until the active tip is at the saphenofemoral junction just distal to the sub-terminal valve. Position of the tip is confirmed by ultrasonography. Tumescent volumes of local anaesthetic are injected in quantities sufficient to separate the vessel from the overlying skin and other delicate tissues along its entire length. Metal fingers at the tip of the RF catheter are deployed until they make contact with the vessel endothelium. RF energy is delivered through the metal catheter fingers and passes through the surrounding tissues; tissue heating occurs both in and around the vessel to be treated. Thermal sensors record the temperature within the vessel. Energy is delivered until the tissue temperature is just sufficient to ensure endothelial ablation. The RF catheter is withdrawn a short distance, and the process is repeated all along the length of the vein to be treated.