The lower limbs of the human body have two venous return systems, the deep vein and the superficial vein. When the superficial vein, i.e. saphenous vein, is taken out as a bridging material during the surgery, one set of return system is gone, which will inevitably cause obstruction of venous return, which is also the reason why the lower limbs will be swollen after the surgery. Therefore, in the early postoperative period, patients need to elevate their lower limbs 20-30cm when lying in bed to promote the venous return of the lower limbs, reduce the swelling of the lower limbs and promote the healing of the incision. At the same time, medical compression stockings are used, which are put on when going down to the ground and taken off after lying down, avoiding prolonged wearing. As there are rich traffic side branches between the deep and superficial venous return system, after a long enough time of postoperative recovery, the side branch circulation will be richer, and the deep veins will slowly be able to play a fully compensatory role, which will not have much effect on the return of venous blood to the lower limbs, so the swelling of the lower limbs of the vast majority of patients will disappear, and this process usually takes several months or even longer. This process usually takes several months or even longer. It will not affect the motor function of the lower limbs. However, there are some patients whose deep venous system function can not be fully compensated, and the patient’s lower limbs are swollen for a long time, in this case, the patient needs to insist on elevating the affected limbs when sleeping for a long time, and insisting on wearing medical compression stockings for a long time when going down to the ground.