In battlefield medicine, when a limb or area is severely injured and infected, there comes a point where removing the infected part is the only way to stop the infection from spreading and to save the patient’s life. Amputation serves as the last resort because it directly removes the source of infection and prevents progression to septicemia or widespread gangrene, especially when the tissue is already nonviable or deeply infiltrated by infection and other treatments can’t control it. Other approaches like removing obviously dead tissue (debridement) and cleansing or irrigating wounds with antiseptics help reduce bacterial load and promote healing, while immobilizing a fracture with a splint helps stabilize the patient. But these strategies aim to salvage tissue or reduce complications, not to halt an infection that has already become systemic or is likely to spread beyond the limb. The amputation is reserved for cases where saving the limb would do more harm than good by allowing continued spread of infection.

This question hinges on when organized facial reconstruction care like the Kent unit really emerged. On the Western Front in World War I, there were massive facial injuries from artillery shrapnel and gas attacks, which spurred the birth of modern plastic and reconstructive surgery. One notable center for this work was in Kent, at facilities in Sidcup (the early facial-reconstruction efforts led by surgeons who pioneered techniques to rebuild faces for injured soldiers). That historical linkage makes World War I the most accurate context for the Kent facial care unit. The other conflicts listed came later, and while trauma care advanced then as well, the specific association with a Kent-based facial-reconstruction unit is tied to the World War I era.

Gillies’ work transformed surgery by establishing plastic and reconstructive surgery as a distinct discipline. During and after World War I he developed and refined techniques for repairing complex facial injuries—highly reconstructive procedures that combined function and appearance. He organized dedicated units, pioneered methods like pedicled and tubed flaps, and introduced staged reconstructions to ensure tissue survival and better outcomes. He also trained a generation of surgeons and authored landmark texts, which solidified plastic surgery as a formal field. While cosmetic considerations became a prominent aspect of the specialty later on, the lasting impact was the creation and advancement of reconstructive plastic surgery, making it the field Gillies profoundly influenced.

The concept at play is how troops were rotated through the fighting line in trench warfare. Frontline trenches were highly dangerous and exhausting, so soldiers did not stay there continuously. They worked in shifts, moving back to support or reserve trenches for rest, meals, repairs, and recuperation before returning to the line. Because only a portion of a soldier’s time was spent in the actual frontline, the typical share ends up around one-sixth, about 15%. That’s why 15% is the best approximation: it reflects the need to rotate troops to reduce exposure while still maintaining the ability to hold the line. The other percentages would imply far more or far less time in the line than historically typical given the constant demands of relief and rest cycles.