Causes of simple varicose veins of the lower extremities: venous valve insufficiency, weakness of the venous wall and persistent increase in intravenous pressure. Causes of venous valve insufficiency: The main cause is venous valve defects. Venous valve defects and weakness of the venous wall are a manifestation of systemic weakness of the supporting tissues and are associated with genetic factors. Important causes of persistent increase in venous pressure in the lower extremities are prolonged standing and increased intra-abdominal pressure. In the formation of simple varicose veins of the lower extremities, the strength of the venous valves and vein walls and the level of venous pressure play an interactive role. The more centrifugal the venous valves and walls are, the lower the strength, and the more centrifugal the venous pressure is, the higher the pressure. Therefore, the distant progress of varicose veins in the lower extremities is more rapid than the initial stage, and the dilated and tortuous superficial veins are more obvious in the calves than in the thighs. In simple varicose veins of the lower extremities, the small saphenous vein is also protected from the direct effect of gravity of the blood column by the superficial femoral and femoral N vein valves, and only after the great saphenous varicose vein progresses to a considerable extent and affects the small saphenous vein by branching, it will present superficial varicose veins in the area of distribution of the small saphenous vein. The veins of the lower extremities become twisted and dilated, the blood returns slowly, or even stagnates by countercurrent flow, and the venous pressure increases. The vein walls become nutritionally impaired and degenerative, especially the muscle and elastic fibers in the middle layer of the vessels atrophy and degeneration and are replaced by connective tissue. Some of the vein walls are cystically dilated and thinned, and some areas are thickened by connective tissue proliferation, so that the vessels may be nodular. Venous valves are atrophied, mechanized, and lose function. Due to depressed blood flow, increased venous pressure and increased permeability of the capillary wall, intravascular fluid, proteins, red blood cells and metabolites leak out into the subcutaneous tissue, causing fibroplasia and hyperpigmentation. The local tissues become malnourished due to hypoxia, and the resistance is reduced, making it easy to complicate dermatitis, eczema, ulcers and infections. The above pathological changes, which mostly occur in the skin of the foot and boot area, generally appear only when the lesion enters the late stage, and most of those who have a family history of simple varicose veins develop soon after puberty, thus, during childhood and adolescence, appropriate physical exercise should be carried out to strengthen the venous walls under the condition of enhancing the whole body fitness. The measures to protect the superficial vein are: 1, those who are engaged in standing work or strong physical labor for a long time, it is advisable to wear elastic stockings for protection, so that the superficial vein can be in the atrophy state; 2, those who are engaged in standing work for a long time, should emphasize to make work gymnastics, or can walk frequently, at least do more ankle extension and flexion activities, so that the gastrocnemius muscle can play the role of effective pump to reduce the pressure within the superficial vein; 3, further update mechanical equipment, improve labor conditions and reduce labor intensity. There are three methods for the treatment of simple superficial varicose veins of lower limbs: 1.Surgical treatment. It is the most commonly used method. Anyone with clinical symptoms, moderate or severe varicose veins, incompetent valves of the superficial veins of the lower extremities and/or valves of the traffic branches between the deep and superficial veins, and those whose examination confirms the patency of the deep veins, as long as they are not too old and not in poor physical condition, should be treated surgically. Surgical methods include: (1) high saphenous vein ligation: applicable to those who have incompetent valves of the large (small) saphenous vein and normal valves of the traffic branches between the large (small) saphenous vein and the deep vein; (2) traffic branch ligation: applicable to those who have incompetent valves of the traffic branches between the large (small) saphenous vein and the deep vein and normal valves of the large (small) saphenous vein; (3) large (small) saphenous vein stripping: most commonly used clinically, applicable to those who have incompetent valves of the large (small) saphenous vein and the deep vein. (3) Saphenous vein stripping: it is most commonly used for those who have incompetent valves of the great (small) saphenous vein and those who have incompetent valves of the traffic branches between the great (small) saphenous vein and the deep vein. It is divided into three steps: high ligation of the vein, stripping the varicose vein and ligation and severing the traffic branch. Theoretically, if the valves of the saphenous vein are incompetent, a simple high ligation and ligation of its branches can block the backflow of deep venous blood and make the varicose vein disappear, thus achieving the purpose of treatment. However, because the vein wall has lost elasticity after superficial varicose vein, the blood of lower limb can still fill the superficial varicose vein when standing, so the effect is not good after simple high ligation, and peeling operation should still be performed. After the operation, use elastic bandage or elastic stocking to give steady and certain elastic pressure to prevent bleeding of the stripping site; elevate the end of the bed 15-20cm, so that the lower limb is slightly higher than the heart plane when lying down, which is favorable to the reflux of the lower limb veins; encourage early bed activity, so that the deep vein blood is squeezed by the muscle pump and accelerate the reflux, which is favorable to prevent the formation of deep vein thrombosis. 2.Injection therapy. Injecting sclerosing agent into varicose vein, a sterile inflammatory reaction occurs in the vein lining, causing the vascular cavity to adhere and occlude, and the varicose vein becomes a sclerotic strip. It is suitable for varicose veins with limited varicose veins and sound valve function and postoperative residual varicose veins. Commonly used sclerosing agents are 5% cod liver oil sodium, phenol glycerin solution and 50% glucose etc. 3.Compression therapy by elastic stocking. It is suitable for those who have small scope, light degree and no symptoms; women in pregnancy; poor general condition, organic lesions of important vital organs, and those who are estimated to have poor tolerance of surgery. The medical elastic stockings for calves have good elasticity, which can make the varicose veins mainly located in the calves, especially the superficial veins in the inner and outer ankles of the boot area, can be effectively compressed.