AT the end of an empty hallway in a Burkina Faso teaching hospital, a group of children sat together in medical gowns, nervously awaiting operations that could save their lives. The smallest, nine-year-old Landry Nion, fixated on a phone game while an older girl cheerfully encouraged him. "After the operation, I would like to become a footballer like Messi," Nion said shortly before his surgery. The five children have become the first in Burkina Faso to successfully undergo open heart surgery. It's a landmark event that doctors say could signal a sea-change for the West African country's healthcare system. Nion…