Two days after crashing during a halfpipe practice run and suffering a severe head injury at the Park City Mountain Resort in Park City, Utah, Canadian freestyle skiing champion Sarah Burke remained in critical condition Thursday after a successful operation to repair a torn vertebral artery that caused cranial bleeding, according to reports.

The 29-year-old Burke was placed into an induced coma by University of Utah Hospital surgeons in Salt Lake City to relieve stress on her brain after her accident Tuesday afternoon and had surgery the next day, according to The Associated Press.

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 William T. Couldwell, M.D., Ph.D, professor and chair of neurosurgery who performed the operation, in a statement released by Burke's publicist Nicole Wool. Our neuro critical care team will be monitoring her condition and response continuously over the coming hours and days.

Canada's National Post reports that Burke 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.

Dr. Andrew Naidech, medical director of the neuro-spine intensive care unit at Northwestern Memorial Hospital in Chicago, told the Post that such a tear can cause bleeding that disrupts blood flow to the brain, which, if serious enough, can lead to brain damage or death.

He also said severe twisting motions or impact causing sudden up-and-down movement of the head causes such a tear. Outcomes depend on how badly damage interrupts blood flow to the brain or causes extensive bleeding.

Powder Magazine reports that Burke was training in the halfpipe with fellow Monster Energy team riders. Around 1 p.m., she landed a trick off of the wall on her feet at the bottom of the pipe, but then whiplashed over onto her side, according to a witness. Burke was then airlifted to the hospital after being stabilized at the scene of the accident.

Burke, a pioneer of her sport as much as a competitor, ranked 11th in the Association of Freeskiing Professionals overall rankings last year and is a four-time Winter X-Games gold medalist in skiing superpipe, which was the event she was training for at the time of Tuesday's accident. She also won gold at the 2005 Finland world championships and in 2007 she was ESPN's Best Female Action Sports Athlete. reports it is unclear what exact trick she was performing when the accident happened.

Burke is no stranger to injury. She missed significant time in 2009 after landing awkwardly and fracturing a vertebra in her lower back. Before this recent injury, she was scheduled to defend her title later this month at the Winter X Games in Aspen, Colo.

Watch a video of Burke winning superpipe gold at Winter X-Games 2011 below: