Liver Trauma

  The liver is one of the most commonly injured solid organ in trauma, it is for this reason, very important to understand its anatomy.  The treatment of liver injuries has evolved over the past hundred years and most significantly during WWII.  Reapproximation with blunt ended suture was first used to control hemorrhage.  Within the past 10 years this treatment has been replaced with packing of the liver while stabilizing the patient, and also conservative, non operative management.  There are two lobes of the liver: left and right.  The line that divides these lobes is known as the “Line of Cantile.”  It travels through the gallbladder fossa anteriorly to left side of the IVC posteriorly. The left lobe containes the left liver parinchima and the Quadrate and Caudate lobes.  The right lobe contains the rest of the liver parinchima. These two lobes are further classified based on resectional segments divided by the distribution of the hepatic veins. These functional segments are known as Couinaud segments. The left lobe is divided into four segments I, II, III and IV.  Left hepatic vein divides anterior (III and IV) and posterior (II) and the caudate lobe (I) drains into the IVC.  The right lobe is divided into four segments V, VI, VII and VIII.  The Right hepatic vein transverses between right posteriolateral (VI and VII) and right anteromedial (V and VIII).

  Another important factor of liver pathology in the trauma setting is the classification of liver injuries.   This classification has been specifically delineated by the American Association for the Surgery of Trauma to provide uniform treatment to liver injuries.  Liver injuries have been successfully treated nonoperatively in the setting of trauma and therefore it is important to understand the indication for surgery. 

The AAST Liver injury grading system is as follows

·       grade I : 

o   hematoma : sub capsular, < 10% surface area 

o   laceration : capsular tear, < 1cm depth

·       grade II : 

o   hematoma: sub capsular, 10 - 50% surface area 

o   hematoma : intraparenchymal < 10cm diameter 

o   laceration: capsular tear, 1 - 3cm depth, < 10cm length

·       grade III : 

o   hematoma : sub capsular, > 50% surface area, or ruptured with active bleeding

o   hematoma : intraparenchymal > 10 cm diameter

o   laceration : capsular tear, > 3 cm depth

·       grade IV :  

o   hematoma : ruptured intraparenchymal with active bleeding

o   laceration : parenchymal distruption involving 25 - 75% hepatic lobes or

o   1 - 3 Couinaud segments (within one lobe)

·       grade V : 

o   laceration : parenchymal distruption involving >75% hepatic lobe or

o   > 3 Couinaud segments (within one lobe)

o   vascular : juxtahepatic venous injuries (IVC, major hepatic vein)

Resources:

Trauma, Feliciano pgs 637-640

http://radiopaedia.org/ for AAST Liver Grading System

http://healthmetz.com/ Image above

Thanks to Dr. Megan O'Toole for this post.