Table 1.

American Association for the Surgery on Trauma Grading System for Anatomic Severity of Disease (8)

Grade	Image AAST (I-AAST) Description of organ	Operative AAST Description of Appendicitis	N
Normal	Normal appearance, Appendix not visualized without any other abnormality	Normal appendix	1 (0.002%)
Grade I	Appendiceal thickening >6 mm with mild periappendiceal edema	Acutely Inflamed Appendix, Intact	230 (68.8%)
Grade II	Appendiceal thickening >6 mm with severe periappendiceal edema,	Gangrenous Appendix, Intact	31 (9.3%)
Grade III	Appendiceal thickening >6mm, severe periappendiceal thickening with free intra-peritoneal fluid in the right lower quadrant/pelvis	Perforated Appendix with Local Contamination	30 (9%)
Grade IV	Appendiceal thickening >6 mm or non-visualized appendix with abscess or phlegmon	Perforated Appendix with Periappendiceal Phlegmon or Abscess	36 (10.8%)
Grade V	Appendiceal thickening >6 mm or non-visualized appendix with free intra-peritoneal fluid > 1 quadrant	Perforated Appendix with Generalized Peritonitis	6 (1.8%)