For decades, the only option for large varicose veins has been surgical removal. Injecting larger veins frequently fails because the flow rate within is so high that the injected solution is simply diluted too fast. Blood clotting never happens because the solution is carried away too rapidly.
Vein stripping is done under anesthesia, in an operating room. An incision is made in the groin, and the largest part of the vein is dissected free, along with all its side branches. A second incision is made below the knee, and the vein is dissected free. A heavy plastic monofilament is passed inside the vein from the knee to the groin, and out a small incision in the vein, at the groin. A small plastic ball is attached and the plastic monofilament is pulled, beneath the skin, from the groin to the knee. This is an efficient way to get 50 cm of vein out without a 50 cm incision. However, the vein is literally 'ripped' out beneath the skin, tearing all the side branches in the thigh, and leaving them to bleed.
This results in moderate bruising, and subsequent pain, that can last for weeks. If there are other larger veins below the knee, they are frequently dissected out individually, through separate incisions. While effective, the result always involves several permanent scars, bruising, pain, and time off work. The time off work is variable, depending on your job. If you work in a physical job, on your feet for long periods, you may be off work for as long as 4 weeks or more, depending on the bruising and blood loss.