AAST (American Association for the Surgery of Trauma) injury scales

Liver

Grade I

• • hematoma: subcapsular, <10% surface area

  • laceration: capsular tear, <1 cm parenchymal depth

Grade II

• • hematoma: subcapsular, 10-50% surface area

  • hematoma: intraparenchymal <10 cm diameter

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

Grade III

• • hematoma: subcapsular, >50% surface area; ruptured subcapsular or parenchymal hematoma

  • hematoma: intraparenchymal >10 cm

  • laceration: capsular tear >3 cm parenchymal depth

  • vascular injury with active bleeding contained within liver parenchyma

Grade IV

• • laceration: parenchymal disruption involving 25-75% of a hepatic lobe or involves 1-3 Couinaud segments 

  • vascular injury with active bleeding breaching the liver parenchyma into the peritoneum

Grade V

• • laceration: parenchymal disruption involving >75% of hepatic lobe

  • vascular: juxtahepatic venous injuries (retrohepatic vena cava / central major hepatic veins)

Notes:

• advance one grade for multiple injuries up to grade III

• for each grade, the worst feature is chosen, either hematoma or laceration (no need for both/all to coexist)

• vascular injury (i.e. pseudoaneurysm or AV fistula): appears as a focal collection of vascular contrast which decreases in attenuation on delayed images

• active bleeding: focal or diffuse collection of vascular contrast which increases in size or attenuation on a delayed phase

Spleen

Grade I

• • subcapsular hematoma <10% of surface area

  • parenchymal laceration <1 cm depth

  • capsular tear

Grade II

• • subcapsular hematoma 10-50% of surface area

  • intraparenchymal hematoma <5 cm

  • parenchymal laceration 1-3 cm in depth

Grade III

• • subcapsular hematoma >50% of surface area

  • intraparenchymal hematoma ≥5 cm

  • parenchymal laceration >3 cm in depth

  • ruptured subcapsular or intraparenchymal hematoma

Grade IV

• • any injury in the presence of a splenic vascular injury* or active bleeding confined within splenic capsule

  • parenchymal laceration involving segmental or hilar vessels producing >25% devascularisation

Grade V

• • shattered spleen

  • any injury in the presence of splenic vascular injury* with active bleeding extending beyond the spleen into the peritoneum

Notes:

• advance one grade for multiple injuries, each up to grade III

• vascular injury (i.e. pseudoaneurysm or AV fistula) appears as a focal collection of vascular contrast which decreases in attenuation on delayed images

• active bleeding: focal or diffuse collection of vascular contrast which increases in size or attenuation on a delayed (i.e. later) phase

Renal

Severity is assessed according to the depth of renal parenchymal damage and involvement of the urinary collecting system and renal vessels.

Grade I

• • subcapsular hematoma and/or contusion, without laceration

Grade II

• • superficial laceration ≤1 cm depth not involving the collecting system (no evidence of urine extravasation)

  • perirenal hematoma confined within the perirenal fascia

Grade III

• • laceration >1 cm not involving the collecting system (no evidence of urine extravasation)

  • vascular injury or active bleeding confined within the perirenal fascia

Grade IV

• • laceration involving the collecting system with urinary extravasation

  • laceration of the renal pelvis and/or complete ureteropelvic disruption

  • vascular injury to segmental renal artery or vein

  • segmental infarctions without associated active bleeding (i.e. due to vessel thrombosis)

  • active bleeding extending beyond the perirenal fascia (i.e. into the retroperitoneum or peritoneum)

Grade V

• • shattered kidney

  • avulsion of renal hilum or laceration of the main renal artery or vein: devascularisation of a kidney due to hilar injury

  • devascularised kidney with active bleeding

Notes:

• advance one grade for multiple injuries up to grade III

• vascular injury (i.e. pseudoaneurysm or AV fistula): appears as a focal collection of vascular contrast which decreases in attenuation on delayed images

• active bleeding: focal or diffuse collection of vascular contrast which increases in size or attenuation on a delayed phase

Pancreas

American Association for the Surgery of Trauma (AAST)

The proximal pancreas is defined as the gland to the right of the superior mesenteric vein (SMV)-portal vein axis whereas the distal pancreas is to the left of the axis. The term deep refers to an injury down to the level of the duct whereas superficial implies the injury is superficial to the duct.

• grade I: hematoma with minor contusion or superficial laceration without duct injury

• grade II: major contusion or laceration without duct injury

• grade III: distal transection or deep parenchymal injury with duct injury

• grade IV: proximal transection or deep parenchymal injury involving the ampulla (and/or intrapancreatic common bile duct)

• grade V: massive disruption of the pancreatic head ("shattered pancreas")

N.b. advance one grade for multiple injuries up to grade 3.

Grades I and II do not involve the duct and are considered low-grade injuries. Grades III, IV and V involve the duct and constitute high-grade injuries.

Wong et al.

A more simple method for grading severity on CT in pancreatic injury proposed by Wong et al. is:

• grade A: pancreatitis or superficial laceration only

• grade B

  • BI: deep laceration involving pancreatic tail

  • BII: complete transection of pancreatic tail

• grade C

  • CI: deep laceration involving pancreatic head

  • CII: complete transection of pancreatic head