Rectal Injury – AAST Classification

The American Association for the Study of Trauma classifies rectal and rectosigmoid injuries into five grades based on severity and presence of devascularization. They are:

Grade 1 – laceration of partial thickness bowel wall or hematoma/contusion

Grade 2 – laceration of bowel wall less than 50% in circumference

Grade 3 – laceration of bowel wall greater than 50% in circumference but less than complete transection

Grade 4 – transection of bowel with extension into perineum

Grade 5 – devascularization of bowel segment