Freestyle skier Sarah Burke dies

Canadian freestyle skier Sarah Burke died Thursday after sustaining serious injuries in a skiing accident on Jan. 10. Burke died at the age of 29 in hospital in Salt Lake City, Utah, after tearing the artery that supplies blood to the brainstem during a training run in the superpipe at a personal sponsor event at the Park City Mountain resort. As the result of a fall after completing a jump, she suffered a ruptured vertebral artery, one of the four major arteries supplying blood to the brain. This caused her to go into cardiac arrest. Emergency personnel responded and CPR was administered on the scene during which time she remained without a pulse or spontaneous breathing. Burke was rushed to hospital, where she was put on life support and therapeutic hypothermia was initiated to protect her brain. On Jan. 11, she had surgery to repair the torn artery, and had been in a medically induced coma until she died on Thursday morning. Irreversible brain damage to Burke resulted from heart stopping: doctors The artery that ruptured when freestyle skier Sarah Burke fell during a training run is one of the most critical blood vessels in the body, feeding oxygen-rich blood to the brain stem, neurosurgeons say. It's the brain stem, located at the bottom of the brain and tucked inside the back of the skull, that controls breathing and heart function. "Basically there are four major blood vessels that bring blood to the brain, and two are at the back of the head, come up from the back," explained Dr. Michael Cusimano, a neurosurgeon at St. Michael's Hospital in Toronto. "They're called the vertebral arteries because they come through the bones of the neck and then get to the brain," he said. The two other major arteries, called the carotids, run up the front of the neck. It was one of her vertebral arteries that Burke tore when she crashed at the training site, causing what's called a massive intercranial hemorrhage, in which blood poured into her brain. Doctors say the severe brain injury caused Burke to go into cardiac arrest. In other words, her heart stopped beating and she was no longer breathing on her own, resulting in a lack of oxygen to the brain. "So right on the scene of this mountain where she was on, where she was training, her heart stopped," said Cusimano. "And so it was probably that the artery was partly torn and that led to this bleeding that her heart stopped."