The B ultrasound examination and intravenous antegrade angiography of deep vein of inferior member before operation showed back flow existed in all 5 limbs in A group ,28 limbs in B and C group , flow back time >0.5s,PVI lies in all the 36 limbs .

• 术前B超及深静脉造影检查显示A组中的5条、B组和C组28条肢体全部存在股浅静脉返流；返流时间>0.；5s；36条肢体均存在PVI。