Recently, scientists were able to engineer for the first time a trachea developed from a patient's own stem cells, wherein a donor's trachea was lined with the patient's stem cells to prevent transplant rejection. Immunosuppressive therapy was not necessary, and the patient remains in good condition months after the surgery. Dr. Paolo Macchiarini, head of thoracic surgery at Hospital Clinic in Barcelona, Spain, delves into the details of this breakthrough surgery with host Dr. Lee Freedman.