VNUS Closure, also known as radiofrequency ablation, is a minimally invasive medical treatment that uses radiofrequency energy to close off problematic veins, particularly in cases of venous insufficiency or varicose veins. The procedure involves inserting a catheter into the affected vein and applying heat to the vein walls, causing them to collapse and seal shut. This redirects blood flow to healthier veins and alleviates symptoms associated with the condition.