Commonly indicated for treatment of sour crop (Fig. 11-11, A), an ingluviotomy is done to retrieve crop calculi, ingluvioliths, or foreign bodies (which are not accessible per os) or to retrieve proventricular or ventricular foreign bodies (using micromagnets [glued in place within plastic tubes], lavage, or endoscopy) and for the placement of an ingluviotomy or proventriculotomy tube or the collection of crop wall biopsies.
Source: wiktionary