Primary lower extremity deep venous valve insufficiency (PDVI) refers to the inability of the deep venous valves to close tightly, causing blood to flow backwards. It may be related to the following factors: 1, weak valve structure, under the effect of persistent reverse blood flow and gravity of the blood column, the free edge of the valve is relaxed and thus cannot close tightly, causing venous blood to reverse flow distally through the cleft between the valve leaflets. 2, due to the persistent overload of the return blood volume, resulting in the enlargement of the venous lumen, so as to cause the valve relatively short and incomplete closure. 3.If the deep venous valves are abnormally developed, only single leaflet or although there are three leaflets but not in the same plane, or if the valves are absent, resulting in venous hypertension and valve closure insufficiency. Pathological changes due to congenital weakness of the vein wall, coupled with long-term blood depression, increased venous pressure, early compensatory thickening of muscle fibers and elastic fibers, late muscle fibers and weak fibers atrophy, disappearance, all replaced by connective tissue, the vein wall often thinned due to expansion, the elastic fibers of the venous valve also degenerated. Although the valve is thin film-like and there is no sign of valve thickening after deep phlebitis, the valve closure is incomplete and the two valve leaflets cannot be closely dovetailed, resulting in incomplete valve closure and downward reversal of blood flow from between the two hypophyseal leaflets. With incomplete deep static valve closure, the blood flow reverses to the distal deep veins, the venous pressure increases, the venous lumen expands and the wall thins, causing capillary congestion, the limb is in a state of chronic edema, the lymphatic vessels may be blocked secondary to the edematous tissue fibrosis making the limb swelling more severe. Persistent deep venous hypertension and incomplete closure of the penetrating branch veins cause blood from the deep veins to flow back into the superficial veins, resulting in secondary varicose veins in the saphenous veins. The slowing down of blood return and reflux in the lower extremities causes depression of blood flow in the lower extremities, decreases the oxygen content of blood, increases the permeability of capillary walls, increases the leakage of red blood cells to the outside of blood vessels, and deposits iron-containing hemoglobin, a metabolite of hemoglobin, under the skin, which often leads to brownish-black pigmentation of the skin in the foot and boot area. Local tissues become malnourished due to hypoxia, and resistance is reduced, making it easy to complicate eczema-like dermatitis, lymphatic vessels and ulcers. According to the severity of clinical manifestations, it can be divided into: 1. mild: heavy discomfort of lower limbs after standing for a long time, dilated or varicose superficial veins, and mild swelling of ankles. 2. 2.Moderate: superficial varicose veins with mild skin pigmentation and subcutaneous tissue fibrosis, heavy feeling in the lower limbs and moderate swelling in the ankle. 3.Severe: swelling and pain or heaviness of the lower leg after a short period of activity, swelling and involvement of the lower leg with obvious varicose veins, accompanied by extensive pigmentation, eczema or ulcers (healed or active). Auxiliary examinations: a. Lower limb venogram When the limb is swollen or there is a long-standing ulcer, it is better to make lower limb venogram to distinguish it from post-deep vein thrombosis syndrome on the one hand, and to clarify the degree of deep and superficial venous valve incompetence on the other hand, so as to provide a basis for developing surgical plan. Generally, the superior venogram is performed first, and then the inferior venogram is performed if the deep veins of the lower extremities are patent, in order to clarify whether there are lesions in the venous valves. The venous valve function is classified into the following 5 levels according to the level of reflux shown by the downstream venogram: Level I: Good valve function. There is no significant regurgitation of the contrast medium. Grade II: Minimal valve insufficiency. Contrast flow to the proximal thigh. Grade III: Mild valvular insufficiency. Contrast flow to the superior knee. Grade IV: Moderate valvular insufficiency. Retrograde flow of contrast to the inferior knee. Grade V: Severe valvular insufficiency. Contrast reversal to the calf up to the ankle level. Second, non-invasive vascular examinations such as ultrasound Doppler flowmetry can also diagnose the presence or absence of venous reflux. Ultrasound Doppler imaging, which allows observation of valve closure activity and the presence or absence of reverse flow. Treatment If the diagnosis is clear and the valve insufficiency is grade II or higher, deep vein valve reconstruction should be considered in combination with the severity of clinical manifestations. The main methods are: 1, femoral vein wall circumferential narrowing (ringing): under normal circumstances, the wide diameter of the valve sinus is greater than the wide diameter of the non-sinus part of the vein, so the use of sutures, tissue pieces or artificial vascular patches wrapped outside the vein to reduce its diameter, restore the ratio of the diameter of the sinus to the vein, valve closure function is then restored. 2, superficial femoral vein luminal external valvuloplasty: through the suture of the vein wall, the angle formed by the two valve leaflet attachment line will be returned from obtuse angle to normal acute angle to restore the closing function. 3.Superficial femoral vein endoluminal valvuloplasty: It is suitable for those who have narrower and less serious valve destruction. Through sutures, the free edge of the flaccid valve is shortened to restore its normal one-way open function. 4.Grafting with valve segment: It is suitable for those who have primary deep venous valve insufficiency grade III-IV on downstream venography or those who cannot perform valvuloplasty due to valve defect or excessive relaxation. A segment with a normal valve is implanted in the proximal side of the superficial femoral vein to replace the valve that has lost its function and stop the backflow of blood.