Surgical Techniques for Liver Transection

Liver resection is still a surgical challenge, due to the high risk of hemorrhage during the transection and the complicated biliary and vascular anatomy of the organ.

The history of the development of surgical techniques for liver resection had it’s main goal, the fight against bleeding. Before 1980’s, liver resection was associated to 10-20% mortality rates.

Currently the in hospital mortality nears 5% in specialized centers. Even though there is a better patient selection, the reduction in blood loss and perioperative transfusions have contributed to the better patient survival. Massive bleeding and transusions not only rise the morbi-mortality risk, but also compromise long term survival after resection of liver tumors, due to the associated immunesuppression, which leads to recurrence.

Finger fracture of the liver parenchyma has been the classic technique for liver resection. During the last 20 years, technological advances have lead to the development of specific instruments such as the compact ultrasonic surgical aspirator, water jet, harmonic scalpel, Ligasure®, and TissuLink®. Another thing that has reduced intraoperative blood loss is the better delineation of the transection plane with the use of IOUS.


Delineation of the Proper Transection Plane

This is not only important to achieve an adequate margin for resection of liver tumors, but also to avoid inadvertent injuries to major hepatic vessels or ducts.

This delineation starts with an adequate knowledge of the computed tomography, to define the different relationships of the tumor and the hepatic veins and biliary pedicles. This can be evaluated transoperatively by IOUS.

Without this knowledge inadvertend injuries may occur during transection, which can lead to massive bleeding or biliary injuries. In some occasions tumor exposition during transection can happen. Generally a 1cm margin is required, but this is still controversial for HCC (Ann Surg 2000; 231: 544-551).

IOUS allows localization of the portal pedicle of each liver segment. Some surgeons perform the liver tattoing with blue dye, injected directly to one portal branch to delineate the segment that is going to be resected.

Techniques of Liver Transection

Finger fracture/clamp crushing

Vacular control is very important to hepatobiliary surgeons. Transection is particularly difficult in cirrhotic livers due to fibrosis. The risk of bleeding is also high in this pathology.

Finger fracture involves crushing the liver parenchyma while under inflow occlusion. This technique was introduced by Lin in 1958 (J Formosa Med Assoc 1958; 57: 742-749). Subsequently was perfected by the introduction of other instruments such as the Kelly clamp (Ann Surg 1974; 180: 285-290). Currently is one of the most widely used techniques today.

Ultrasonic Dissection

In a lot of centers, the use of Cavitron® CUSA (Compact Ultrasonic Surgical Aspirator) has been the standard for liver resection. With this technology, liver parenchyma is fragmented by means of ultrasonic energy and aspirated exposing the vascular and ductal structures, which can be clipped or ligated.

This technique has demonstrated reduction in blood loss, morbidity, when compared with finger crushing. The surgical margin is also wider with this technique (Br J Surg 1996; 83: 117-120).

Water Jet

The water propulsion dissector uses a water jet instead of ultrasonic energy to fragment liver parenchyma and expose vascular and biliary structures. This technique is not as popular as CUSA. Currently only one study showed the results with this technique (Zentralbl Chir 2001; 126: 586-590).

Harmonic Scalpel

More recently, newer technologies have allowed sealing of lesser vessels during liver transection. This technique can be used alone or in conjuction with others, such as finger crushing or CUSA.

It uses ultrasonicaly activated shears to seal small vessels that stand between the vibrating blades. The blades vibrate at 55.5 kHz and can easily dissect parenchyma. The coagulative effect is caused by protein denaturalization that occurs due to destruction of hydrogen bonds and heat generation. The tissue cutting effect derives from a saw mechanism.

It has been used in laparoscopic and open procedures, without reported biliary leaks in Schmidbaier’s study in 2002 (Ann Surg 2002; 235: 27-30).

One disadvantage of this technique is it’s capacity to dissect the liver parenchyma around the hepatic veins, because of its difficulty in controlin large vessels. Even though, it is widely used in laparoscopy.

Ligasure

Another instrumet designed for sealing small vessels using a different principle. Combining compression and bipolar radiofrequency energy, a change in the vessel wall’s collagen and elastin, sealing of vessels as large as 7 mm can be achieved.

Doubts concernig its capacity of sealing large bile ducts persist, and ths was reafirmed in a recent study (World J Surg 2005; 29: 110-112). It is useful for laparoscopic procedures.


TissueLink

A new technology using saline-linked radiofrequency energy has been developed. The saline runs towards the tip of the instrument to link the radiofrequency energy with liver surface, achieving coagulation.

This instrument has a tip that allows transection and vessel sealing simultaneously. Can be used during laparoscopic surgery. You can watch a video here.

Radiofrequency Assisted Liver Transection

Radiofrequency ablation is a good technoque for the treatment of liver tumors. With this technique, a Cool-tip® electrode is inserted in the transection plane serially every 1-2 cm, applying energy for 1-2 minutes, to create coagulated cylinders, that then can be cut by a scalpel.

The advantage of this technique is its simplicity, when compared to the other techniques. One of the potential disadvantages is the sacrifice of liver prenchyma that is coagulated, leaving up to 1 cm of necrotic tissue, which can be critical in cirrhotic patients.

There exists the concern for damage to the hilar structures and hepati veins. The use of this device has to be evaluated. You can watch a video here.




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