In the feet there is very little muscle and fat tissue surrounding the veins. The arteries, veins and nerves are all very close together in the feet. With all of these vessels being in very close proximity there is a high risk of causing problems to the artery or nerve when the vein is treated. If veins are treated in the feet, irritation and inflammation in the foot can cause spasm in the artery or nerve that can cause permanent problems. These problems can include necrosis or tissue death, chronic numbness and the possibility of foot drop or the inability to lift the toes up when walking.