Grade	AAST disease grade	Corres- ponding Hinchey grade	Management	References
I	Local disease; confined to the organ; minimal abnormality	N/A, O	Outpatient care Selective antibiotics	2 3 4 9 10 11 14 3 4 9 11
II	Local disease; confined to the organ; severe abnormality	I, I	Outpatient care Selective antibiotics	2 3 4 9 10 11 14 3 4 9 11
III	Beyond the organ; locally advanced only	I, II	Antibiotics±percutaneous drainage	3 4 9 10 11
IV	Beyond the organ; regional extension	II, III	Antibiotics±percutaneous drainage	3 4 9 10 11
V	Beyond the organ; widespread involvement	III, IV, IV	Resection with stoma Selected single-stage operations	3 4 9 11 3 4 7 9 10 11