The process of organ procurement: Liver - the cold dissectionWritten by Ivo Mitsiev at in "Transplant Surgery".
The cold dissection is the part with the most surgical variants and I want to stress again the fact that the described way is the one that I use, well knowing that this is only one of many possible ways to perform an organ procurement in general and a cold dissection in particular.
Three liters of 4°C cold University of Wisconsin (UW) solution are used to flush the arterial line and 1 liter for the portal flush. The quality of the flush can be assessed by evaluating the outflow of the supradiaphragmatic IVC which should turn more transparent with the time as the blood in the abdominal organs becomes replaced by the preservation solution. After the flush is completed some of the ice is removed from the abdomen to allow a dissection of the structures.
Identification and dissection of the gastroduodenal artery (GDA) is the first part of the cold dissection because I use this artery to find the common hepatic artery (CHA). Initially I leave a long GDA-stump. Following the artery back, one should come to the bifurcation off the CHA. Then I dissect the connective and lymphatic tissue on top of the CHA following the structure backwards to the aorta. On this journey, the splenic artery should be found first branching to the left. It becomes dissected and again a long stump is left unless a pancreas procurement is performed too when the stump will be very short (just to ligate the vessel). The next artery branching will be the left gastric one which is usually next to the bifurcation of the splenic artery, often building a trifurcation. Once it is also dissected and ligated with a 2-0 silk tie, the celiac artery must not be followed the whole way back to the aorta. The aortic clamp is used for orientation where to transect the aorta which could be performed on the cranial part of the clamp before removing it.
The dissection of the portal vein is, now that the CBD and the GDA are divided, easy. Unless a pancreas procurement is performed, the portal vein is followed back (by dividing the head of the pancreas) to the confluence of the splenic and the Superior Mesenteric Vein (SMV) which I cut separately. This is the way I make sure that the whole length of the portal vein is taken.
The attention now is directed to the IVC. The location for division of the infrahepatic IVC depends on the renal veins. These are identified on both sides and the IVC can be safely divided on the virtual line about 5 mm above the renal veins.
While still in this area, I dissect the Superior Mesenteric Vein (SMA) which is found coming out of the aorta just above the left renal vein. Dissecting on the left side of the SMA, I make sure that a possible replaced or accessory right hepatic artery is not damaged. This is coming (if ever) on the right side of the SMA shortly after its branching from the aorta.
A senior fellow told me once that he found a replaced right hepatic artery coming directly from the aorta. This is "mean" but cutting a possible replaced/accessory right hepatic artery is not a dramatic situation as the reconstruction of these arteries is usually done end-to-end either to the GDA or the splenic stump. The stump of the replaced/accessory right hepatic artery should be not too short to perform this reconstruction though.
The renal arteries are usually just below the SMA. They should be visualized before the suprarenal aorta is divided. After dissecting the aorta and identifying the renal arteries I usually transect cranio-posteriorly the offspring of the SMA in 45 deg. and first look for ostia of accessory renal arteries before performing complete separation of the aorta.
At this point the main structures which we need for the liver transplantation are dissected and divided.
Placing a finger in the supradiaphragmatic IVC helps identifying it during transection of the diaphragm, performed usually with Mayo scissors. A good portion of the diaphragm should be kept with the liver to ensure that this gross and fast dissection does not damage the organ. The diaphragm is cut to the right, around the right triangular ligament of the liver. The incision is then continued between the right kidney and the liver, usually dividing the adrenal gland which is always a good sign that none of the next organs are damaged. The liver can be then placed in the right thoracic space maximally exposing the hepato-duodenal ligament which can be now divided. Performing this one should have in mind the vascular structures in this ligament. Even though they are already dissected, they are usually left long enough and could be therefore unintentionally injured if not enough attention is paid. Usually I take these structures with my left index finger leaving the ligament between the index and the middle finger of the left hand. This way I make sure that the vessels are placed left of the transection line in the hepato-duodenal ligament.
The only structure holding the liver in the abdomen now is the aorta. Placing the left middle finger in the aorta and holding the CHA left of the aorta gives nice and safe exposure to the retroaortic space while applying gentle traction on the aorta to the right. The aorta is then divided from the spine and the diaphragmatic muscle.
The liver is now free and taken out of the abdomen.
A second perfusion with the preservation solution should be performed on the back table before packing the liver in the transportation box. I use a liter of UW solution and perfuse the portal vein with 700 ml, the artery with 250 ml and the CBD with the rest 50 ml. While perfusing the liver I look for the outflow of the IVC and would aggressively consider a perfusion with an additional liter (which is used completely for the portal flush) if this outflow is still too bloody.
The reason for the portal preference in the back table flush is the fact that the portal vein contributes about 70-80% to the liver circulation and was flushed with a liter only during the in-situ perfusion. There is no need to delay it with a second liter as this could be safely done on the back table with a better control.
The liver is now flushed and can be packed in the transportation box.