Liver injury grading system

The AAST Liver injury grading system is as follows

• grade I : 
  • haematoma : sub capsular, < 10% surface area 
  • laceration : capsular tear, < 1cm depth
• grade II : 
  • haematoma: sub capsular, 10 - 50% surface area 
  • haematoma : intraparenchymal < 10cm diameter 
  • laceration: capsular tear, 1 - 3cm depth, < 10cm length
• grade III : 
  • haematoma : sub capsular, > 50% surface area, or ruptured with active bleeding
  • haematoma : intraparenchymal > 10 cm diameter
  • laceration : capsular tear, > 3 cm depth
• grade IV :  
  • haematoma : ruptured intraparenchymal with active bleeding
  • laceration : parenchymal distruption involving 25 - 75% hepatic lobes or
  • 1 - 3 segments (within one lobe)
• grade V : 
  • laceration : parenchymal distruption involving >75% helpatic lobe or
  • > 3 segments (within one lobe)
  • vascular : juxtahepatic venous injuries (IVC, major hepatic vein)
• grade VI : vascular : hepatic avulsion