Woodcut. Interior scene showing amputation of leg, with cautery irons in fire in foreground. Gangrene is a serious and potentially life-threatening condition that arises when a considerable mass of body tissue dies (necrosis). Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery (removal of all or part of a limb, an organ, or projecting part or process of the body). As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for such problems. Amputation most often occurs with severe limb injuries in which the limb cannot be spared or attempts to spare the limb have failed.