Renal cancer is a common malignancy of the urinary tract and can form aneurysmal emboli in the renal and inferior vena cava with an incidence of approximately 4% to 15%. It is now generally accepted that inferior vena cava thrombosis is not an independent poor prognostic factor for tumors, and aggressive surgery is still the best treatment for most patients with renal cancer combined with inferior vena cava thrombosis. 1.Definition of inferior vena cava thrombosis. Inferior vena cava tumor embolus refers to a new organism formed by a tumor extending into the lumen of the inferior vena cava vessels. The tumor embolus originates from the vein where the tumor is located and extends to the renal vein, inferior vena cava, and even the right atrium and right ventricle. Most of the tumor thrombi extend along the vena cava, and only a few of them invade the vein wall. 2. Staging of inferior vena cava tumor embolism. Grade 0: the tumor is confined to the renal vein; Grade I: the tumor invades the inferior vena cava and the tip is ≤2cm from the opening of the renal vein; Grade II: the tip of the tumor is >2cm from the opening of the renal vein but below the level of the hepatic vein; Grade III: the tumor grows to the level of the inferior vena cava in the liver but below the level of the diaphragm; Grade IV: the tumor invades the inferior vena cava above the level of the diaphragm. vein. According to the TNM staging criteria of AJCC in 2002, the combination of renal vein and inferior vena cava aneurysm embolism is classified as T3b, and the combination of inferior vena cava aneurysm embolism is classified as T3c. 3. Diagnosis of renal cancer with inferior vena cava aneurysm embolism. Generally speaking, patients with renal cancer with inferior vena cava aneurysm embolism have no specific clinical manifestations. In addition to local symptoms and systemic symptoms caused by the primary cancer, they may also have swelling of lower limbs, varicose veins of lower limbs, varicose veins of spermatic cord, varicose veins of abdominal wall, hepatic vein obstruction syndrome, as well as symptoms and signs of cardiovascular metastasis (such as dyspnea, jugular vein anger, heart murmur, etc.) caused by inferior vena cava obstruction. Unless the inferior vena cava is completely atretic and no collateral circulation is formed, the clinical manifestations are not obvious and the diagnosis mainly relies on imaging examinations. Color Doppler ultrasound is useful in the diagnosis of inferior vena cava aneurysms, and arterial spectroscopy can be used to identify aneurysms or thrombi, depending on factors such as intestinal gas, obesity, and the skill level of the physician. CT scan shows a block or long filling defect in the vena cava, and the embolus is hypo- or isointense, which can clearly show the size and location of the vena cava embolus, but its accuracy is lower than that of MRI and endoesophageal scan. In recent years, transesophageal interventional ultrasound or intraoperative interventional ultrasound has been used to determine the location, size, and extension of vena cava emboli, to determine blood flow, and to differentiate them from thrombi, which has greatly improved the diagnostic accuracy in It is considered necessary in laparoscopic surgery for combined inferior vena cava thrombosis. Kang Ning et al. introduced the application of intraoperative interventional ultrasound in the surgery of renal cancer combined with inferior vena cava tumor embolism, which can check the presence or absence of tumor embolism and invasion intraoperatively, correct the preoperative tumor embolism staging, clarify the scope of vascular blockage, and play a great role in no tumor embolism dislodgement and no tumor embolism residue intraoperatively. 4.Surgical technique of inferior vena cava tumor embolism. The basic principles of surgery are to expose and control the inferior vena cava above and below the tumor embolus, the contralateral renal vein and the involved lumbar veins; to completely remove the tumor and the tumor embolus; to prevent tumor embolism; to minimize bleeding; to maintain hemodynamic stability; and to minimize the ischemic time of the liver and kidney and other important organs. Different surgical options should be chosen according to the different levels of tumor emboli: ①Grade 0 tumor emboli surgical option: laparoscopic minimally invasive technique is used, if technical conditions are not available, open surgery is feasible, and the renal vein is cut at the proximal end of the tumor embolus, together with the kidney and perinephric fat, without blocking the contralateral renal vein and vena cava. ②Surgical plan for grade I and II tumor embolus: choose Chevron incision and so on, which can effectively control large abdominal vessels, facilitate ligation of renal arteries and veins, reduce bleeding, and facilitate the treatment of large renal tumors. For tumor embolus far from the hilar position, Satinsky forceps can be used to clamp the inferior vena cava above and below the tumor embolus, cut the inferior vena cava wall at the level of renal vein, remove the tumor embolus, and excise it together with the tumor, kidney, and perirenal fat. The cut inferior vena cava can be sutured in situ or patched with pericardial patch, and usually no adjuvant surgical technique is required. With the development of minimally invasive technology, for kidney cancer combined with grade 0, grade I or even grade II tumor embolus, laparoscopic minimally invasive technology can be used to complete tumor embolus removal surgery. It has been reported that laparoscopic technology has been used to complete radical surgery for kidney cancer combined with grade II tumor embolus without intraoperative and postoperative complications, reducing patient pain and significantly reducing surgical wound and recovery time. The location and limits of the inferior vena cava tumor thrombus were detected by laparoscopic interventional ultrasound and the blood flow signal was detected, and the tumor and tumor thrombus were completely removed. (iii) Surgical options for grade III and IV tumor emboli: Grade III and IV tumor emboli have wide extension and are technically difficult to operate, requiring close cooperation between cardiothoracic surgery, vascular surgery, anesthesia and other departments, and require adjuvant surgical techniques to complete. The Chevron and sword thoracic angle extension incision or combined thoracoabdominal incision can be chosen, which usually requires cardiopulmonary bypass, deep hypothermia stopping circulation or intravenous diversion and other auxiliary techniques. If necessary, a simultaneous open-chest incision can be chosen to facilitate timely embolization in case of pulmonary embolism and to prevent fragmentation when removing the embolus from the atrium or lung. If the inferior vena cava wall defect is severe, revascularization can be performed by artificial vessels and so on.