Actually, there were many... submarine warfare for one... but also, "... World War I gave us blood banks that made possible blood transfusions among wounded soldiers in the Army Medical Corps in France. The First World War also pushed medicine further along the path to modern wound management, including the treatment of cellulitic wound infections, i.e., bacterial skin infections that followed soft tissue trauma. Battlefield surgeons were quick to appreciate the need for thorough wound debridement and delayed closure in treating contaminated war wounds. The prevalence of central nervous system injuries – a tragic byproduct of trench warfare in which soldiers’ heads peered anxiously above the parapets – led to “profound insights into central nervous system form and function.” The British neurologist Gordon Holmes provided elaborate descriptions of spinal transections (crosswise fractures) for every segment of the spinal cord, whereas Cushing, performing eight neurosurgeries a day, “rose to the challenge of refining the treatment of survivors of penetrating head wounds” (Arch. Neurol., 51:712, 1994). His work from 1917 “lives today” (ANZ J. Surg., 74:75, 2004).
No less momentous was the development of reconstructive surgery by inventive surgeons (led by the New Zealand ENT surgeon Harold Gillies) and dentists (led by the French-American Charles Valadier) unwilling to accept the gross disfigurement of downed pilots who crawled away from smoking wreckages with their lives, but not their faces, intact. A signal achievement of wartime experience with burn and gunshot victims was Gillies’s Plastic Surgery of the Face of 1920..." (Source: Medicine, Health and History).