Colon Injury – AAST Classification

The American Society for the Study of Trauma (AAST) grades colon injury according to severity and devascularization injury. The grades are as follows:

Grade 1 – partial bowel wall laceration or presence of contusion or hematoma

Grade 2 – laceration involving less than 50% of bowel wall

Grade 3 – laceration involving more than 50% of bowel wall, but less than full transection

Grade 4 – complete transection of bowel wall

Grade 5 – complete transection of bowel wall with presence of devascularized segment