Twins girls who were born joined at the head have gone home to Guatemala, five months after surgery to separate them. The prognosis for both is good.

Wearing tiaras over their bandages, the 17-month-old sisters left the children's hospital at the University of California, Los Angeles. Medical workers saw them off Monday, in a farewell one nurse called "bittersweet."

"We know that this is best for them and they need to be back in their hometown, but we've grown really attached to them and it's going to be hard for us," she said

The girls, known as the two Marias, were born fused at the skull with their faces tilted in opposite directions. They were brought to Los Angeles with help from a charity called Healing the Children.

Doctors describe the 23-hour procedure to separate the girls as one of the most difficult in the hospital's history. On several occasions, one of the girls was near death.

An anonymous donor contributed $450,000 toward the $2 million cost of their medical care. UCLA physicians donated their services.

Dr. Henry Kawamoto says the team that cared for the twins included physicians from India, Argentina and Israel, as well as the United States. He calls the successful treatment a cooperative endeavor.

"As the twins go back to Guatemala, we're really exporting some of the best of American technology, American goodwill, and hopefully a message that says, people of the world, we can work together to bring a lot of joy," he said.

At home, the girls will undergo physical therapy and further operations, including plastic surgery to allow them to grow full heads of hair.