Varicose veins grow by increasing amount and pressure in the superficial venous system. This system can act as a water box to store blood, a reservoir. If you keep too much blood, your veins will grow.
The deeper veins have muscle compartments and fascias that control growth. The superficial ones only have fat and skin, what offers less resistance.
The picture below shows an image showing the position of the various veins in the legs. The video on the Youtube link shows what happens to a system when a new entry point flows into it. It would be the example of a superficial venous system in the leg when it receives reflux of the deep venous system by alteration.
Thus, we consider that it is not necessary to destroy the venous capital of the leg to treat varicose veins. If the source of liquid in the system is properly discontinued, we can obtain improvement of the patient without eliminating the veins.