Maurice Gibb of the Bee Gees died because his bowel and small intestine had become so twisted they restricted his blood flow, according to autopsy results released Thursday.

Gibb, 53, died Sunday, three days after suffering cardiac arrest prior to undergoing emergency surgery for an intestinal blockage.

Dr. Bruce Hyma, the Miami-Dade County medical examiner, said Gibb died because a condition called ischemic enteropathy restricted the flow of blood to his bowel.

The autopsy, which was performed Tuesday, did not give the immediate cause of the twisting, but it said the singer was born with a malformed intestine that experts said can lead to life-threatening kinks.

"It's very uncommon, what happened to him," said Dr. Jeffrey Raskin, interim chief of gastroenterology at the University of Miami medical school.

"People [with his condition] can live to middle age with no symptoms. They can have minor problems off and on. Or, they can present on the first time with a catastrophic event, as it seems in this case," said Raskin, who was not involved in Gibb's treatment.

Raskin said a twisted bowel can cause an array of internal problems.

"It can lead to a cardiovascular collapse and possibly could have contributed to the cardiac arrest," he said.

Gibb's brothers, Robin and Barry Gibb, have questioned the decision by doctors at Mount Sinai Medical Center in Miami Beach to operate after their brother's cardiac arrest. A hospital spokeswoman declined comment Thursday.

Carol Peters, a spokeswoman for Bee Gees manager Allen Kovac, was flying back to California on Thursday and could not be reached for comment.

Gibb played bass and keyboard for the Bee Gees, who won seven Grammy Awards, were enshrined in the Rock and Roll Hall of Fame and were best known for disco hits like "Stayin' Alive." His funeral was held Wednesday.