Johan Friso may be a prince who never wakes up.

The Dutch royal may never regain consciousness from a coma, Austrian doctors said Friday. A massive avalanche buried Friso, choked off oxygen for 15 minutes and left him severely brain-damaged, The Associated Press reported.

The 43-year-old prince was on a skiing holiday in the Austrian ski resort Lech. Friso and up to three other people skied off trail when the avalanche struck, the BBC reported.

Rescue workers said Prince Friso remained under snow for 15 minutes before being freed. However, emergency personnel took 50 minutes to revive the prince. During that time, he suffered severe brain damage. Dr. Wolfgang Koller, head of the trauma unit at Innsbruck's University Hospital, said MRI brain scans confirmed the result.

We cannot say today with certainty whether Prince Friso will one day regain consciousness, Koller told the BBC News.

Thousands of people each year become incapacitated through comas, but most patients regain consciousness.

Half of comatose patients regained awareness after one year of being in a coma, according to data from the Traumatic Coma Data Bank.

The pivotal 1991 survey included 650 patients who, like Friso, had suffered severe head injuries. A team of researchers from the University of Texas Medical Branch also found that three years post-injury, 42 percent of patients remained in a coma.

The most extreme coma case came from Elaine Esposito, who survived 37 years, three months and 20 days in a coma that resulted from an appendectomy when she was six years old, according to a report from The Associated Press at the time of her death.

For 37 years, Elaine's mother, Lucy, took care of her comatose daughter, bathing, feeding and dressing her daughter with a hair bow or clip each day.

Lou Esposito, Elaine's father, died of cancer 10 months before his daughter died in 1978.

I lost them both within 10 months, Esposito told The Associated Press at the time of her daughter's death. Lou and I always figured Elaine would go first and we'd have a few years for ourselves.