Neurosurgeons from around the globe are heading back to their homes today after spending the past few days learning a rare procedure at the Saint Louis University School of Medicine. It’s brain artery bypass surgery, which involves the use of an artery from a patient’s arm or leg to replace the artery in the area being operated on. Saint Louis University School of Medicine is one of the few centers in the world which teaches this rare procedure considered by some to be the surgery of last resort.