Editing Open Kidney Surgery (section)

==== Level III-IV vena caval thrombectomy: intra-abdominal approach ====

* Pre-operative planning
**Operating room should be set up for possible cardiopulmonary bypass (CPB), including deep hypothermic arrest. 
**Intraoperative TEE 
***Should be available to measure the cranial extent of the thrombus and to monitor the thrombus for fracture and embolization. 
***Cardiac function is evaluated with TEE so that the anesthesiologist can appropriately manage the patient’s hemodynamics.
* '''The key decision for level III thrombi is whether to attempt an intra-abdominal thrombus extraction with complete hepatic mobilization or use a combined intrathoracic/intra-abdominal approach with bypass.''' 
**This decision can only be made intraoperatively, after the renal artery is ligated, the liver is mobilized, and the IVC is exposed and evaluated. 
**It is preferable to clamp the IVC below the hepatic veins, since the venous return from the liver is significant. 
**As a rule of thumb, patents with free-floating partially occlusive thrombi will not tolerate suprahepatic clamping very well and should probably undergo bypass. Contrarily, patients with completely occlusive thrombi will typically have developed extensive collateral venous drainage networks and therefore tolerate clamping much better. 
**Occasionally, a level IV thrombus can be milked into the abdomen through a small diaphragmatic incision and treated intra-abdominally. 
**It is crucial that IVC control not compromise the operation since bleeding and hypotension can lead to an incomplete tumor resection, a result that is universally fatal. 
* Surgical plan
**Position: anterior midline incision for level III and IV thrombi; a chevron incision with added sternotomy can also be used. 
**Expose the right kidney and great vessels, as described for a level I thrombus
**Ligate the right renal artery is ligated in the interaortocaval area. 
**Dissect the infrahepatic IVC is gently. 
**Isolate the infrarenal IVC and left renal vein and Rummel tourniquets are placed around them.
**Mobilize the liver
***Ligate and divide the ligamentum teres, the remnant of the obliterated left umbilical vein that is located at the lower free border of the falciform ligament. 
***Divide the falciform ligament up to the upper border of the liver where it branches into the coronary ligament on the right and the left triangular ligament on the left. 
***Divide the superior layer of the coronary ligament with scissors or electrocautery, taking care not to injure the liver or the IVC, which is located just behind the ligament in the bare area of the liver. Division of the superior layer of the coronary ligament continues along the right border of the liver until it forms the right triangular ligament (the fused superior and inferior layers of the coronary ligament), which should also be divided. Mobilization of the right lobe of the liver is completed by dividing the inferior layer of the coronary ligament, the attachment that ties the liver to the diaphragm, upward toward the IVC.
***The left triangular ligament is divided anteriorly and hepatic mobilization is completed by dividing the posterior aspects of the left triangular ligament toward the IVC. The right lobe of the liver can now be safely and gently rotated toward the midline so that the IVC can be evaluated on the posterior surface of the liver. For tumors of the left kidney, it may be necessary to divide the diaphragmatic attachments of the spleen so that it can be rotated toward the midline with the pancreas without being traumatized.
**'''Develop the plane between the posterior surface of the liver and the anterior surface of the IVC.''' 
***The help of a hepatic surgeon with this portion of the procedure should be considered. 
***This plane contains venous branches from the liver that are divided into upper and lower groups. 
****The most important group is the upper group that contains the right, middle, and left hepatic veins, the principal outflow from the liver, and therefore cannot be divided. Tumor thrombus can extend into these veins and they must be carefully inspected and cleared of any thrombus during thrombectomy. Obstruction of these three veins leads to the Budd-Chiari syndrome. 
****The lower group of hepatic veins (the accessory hepatic veins) drain blood principally from the caudate lobe (with a small contribution from the right lobe) and can be safely divided. The accessory hepatic veins are ligated with 2-0 silk and the plane between the IVC and the liver is developed. 
***Additionally, the lumbar veins are ligated with 2-0 silk and the plane between the IVC and the posterior abdominal wall is developed. '''The IVC should now be fully mobilized.'''
**'''Create a  window in the lesser omentum and encircle the porta hepatis''' (also called the portal triad or hepatic pedicle)''', which contains the portal vein, common hepatic artery, and common bile duct, with a Rummel tourniquet.''' 
***Clamping the porta hepatis (the Pringle maneuver) is necessary to prevent massive blood loss if the IVC is clamped above the major hepatic veins. 
***Clamping the IVC above and below the hepatic veins while performing a Pringle maneuver is called total hepatic vascular occlusion. 
***If the IVC is clamped below the major hepatic veins and the accessory hepatic veins are ligated, the Pringle maneuver may not be necessary. 
***Under normothermic conditions, the porta hepatis can be clamped for up to 60 minutes, although a clamping time of 20 minutes or less is preferred since ischemic hepatic injury and portal vein thrombosis can ensue. Another complication of the Pringle maneuver is splenic engorgement and rupture as a result of backup of venous drainage from the splenic vein, which normally empties into the portal vein.
**'''Determine the resectability of the tumor and thrombus is using TEE and a thorough intraoperative assessment of the anatomy.''' 
***'''If the thrombus is below the hepatic veins or can be milked below these veins, it is usually safe to proceed without bypass.''' 
***'''If the thrombus involves the hepatic veins or extends above the liver, bypass is often required.''' 
**The IVC is occluded above the liver and thrombus and the patient’s hemodynamic response is observed over 2 to 5 minutes. 
***Clamping the suprahepatic IVC results in a 60% reduction in cardiac preload, an increase in peripheral vascular resistance of 80%, an increase in heart rate of 50%, a drop in cardiac output of 40%, and a drop in mean arterial blood pressure of 10% to 20%. If the cardiac output drops more than 50% or the mean arterial blood pressure drops more than 30%, the patient will not tolerate suprahepatic IVC clamping. Options for managing this situation include bypass (our preference) and clamping of the supraceliac aorta. 
***If the IVC clamping trial is tolerated and the thrombus can be removed in less than 30 minutes, it is safe to proceed with the intra-abdominal procedure.
**'''In sequence, the infrarenal IVC, the contralateral (left) renal vein, the porta hepatis, and the suprahepatic IVC are clamped.''' 
***For left-sided tumors, the right renal artery should be clamped prior to the right renal vein since there is no good collateral venous drainage for the right kidney. 
**'''Incise the ostium of the right renal vein is circumferentially and extend the incision toward the intrahepatic IVC.'''
***The incision should be large enough to permit extraction of all of the tumor thrombus and careful inspection of the intima of the IVC. 
**'''Excise the thrombus and kidney.''' 
***With the help of a Penfield dissector the IVC is cleared of adherent thrombus. 
****If involved with tumor that cannot be scraped away, the IVC should be completely or partially resected and reconstructed (see below).
***A Fogarty balloon catheter (Edwards Lifesciences Corporation, Irvine, CA) or 20-Fr Foley catheter can be used as an embolectomy catheter if the thrombus is out of reach.
**Close the IVC is closed as described for level II thrombus. The hepatic ligaments are tacked back into place to prevent torsion of the liver. 
**A regional lymphadenectomy is performed and a closed suction drain is inserted.