Yvelot Brianville, 24, lies quietly on a steel hospital gurney, a boyish naval officer in blue combat fatigues standing by his side. The officer, Lt. Cmdr. Mill Etienne, 34, is Haitian, fluent in Creole. He is also a neurologist, called to the intensive-care ward of this floating U.S. Navy hospital just off the coast of Port-au-Prince to assess the impact of Haiti's earthquake on one man's spine.