Any surgery has certain risks, and the greater the surgery, the greater the risks will be. Judging from the severity of the disease, the advantages and disadvantages of surgery and non-surgical surgery will outweigh the risks to people. The risk of post-operative infection is inevitable in leg thrombosis removal surgery or filter placement surgery, but if anticoagulant medication is used as prescribed by the doctor and medication is changed on a daily basis, the risk of infection will be reduced. The risk of anesthesia is not significant as long as the preoperative anesthesiologist has evaluated the patient, taken into account all underlying medical conditions and agreed to the procedure, which would be fatal if the leg thrombosis is not treated. The thrombus can produce severe pain in the lower extremity, and if the thrombus is large enough to cause ischemia in the lower extremity, it may cause gangrene, and if the embolus is dislodged it may cause a pulmonary embolism which is fatal.