Answer:
The saphenous is not necessary in the sense that an individual will live without it. It may be harvested to use as material for coronary bypass grafts (heart surgery). Years ago, it was a commonly excised (surgically removed) vein in varicose vein surgery. After two weeks in bed, the patients body had developed the ability for the blood to find it's way back to the heart through smaller veins. There are much improved techniques today, but it defines the fact that the vein is not absolutely necessary, it can be "worked around".