SALT LAKE CITY -- Canadian freestyle skier Sarah Burke remained in critical condition Thursday after a successful operation to repair a tear to an artery that caused bleeding in her brain.
Doctors put her into a coma to relieve stress on her brain after her accident Tuesday, and she had surgery the next day.
"With injuries of this type, we need to observe the course of her brain function before making definitive pronouncements about Sarah's prognosis for recovery," said Dr. William Couldwell, the neurosurgeon who performed the operation, in a statement released by Burke's publicist. "Our neuro critical care team will be monitoring her condition and response continuously over the coming hours and days."
Burke, a four-time Winter X Games champion in halfpipe skiing and one of the leading pioneers of her sport, injured herself while practicing on the halfpipe in Park City.
She tore a vertebral artery, which is located in the neck and supplies blood to the brainstem -- the back part of the brain which controls consciousness.
Tears can cause bleeding that disrupts blood flow to the brain, which in serious cases can lead to brain damage or death, said Dr. Andrew Naidech, medical director of the neuro-spine intensive care unit at Northwestern Memorial Hospital in Chicago.
He said those tears can be caused by severe twisting motions or impact causing sudden up-and-down movement of the head. Outcomes depend on how badly the damage interrupted blood flow to the brain or caused extensive bleeding.
Peter Judge, CEO of the Canadian freestyle team, said those who were near the superpipe when Burke fell told him it didn't look like a major accident at the time.
Burke tried many of the toughest tricks in her sport and was the first woman to land a 1080 -- three full revolutions -- in competition. It was not known what move she was performing when the accident happened.