PALO ALTO, Calif. -- Conjoined California twins Eva and Erika Sandoval have become two separate toddlers following a 17-hour marathon surgery at the Lucile Packard Children's Hospital Stanford that began on Tuesday, officials said.
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The Sacramento Bee reported the 2-year-old Sacramento area girls were born conjoined from the chest down and shared a bladder, liver, parts of their digestive system and a third leg.
Their parents said each girl has retained portions of the organs they shared. Each girl still has one leg and surgeons told the newspaper both would likely need a prosthetic leg. The third limb was used for skin grafts to cover surgical wounds.
Their parents were overjoyed with the success of the separation, which father Arturo Sandoval called a "major success."
"They look amazing. They're amazing. They have their hair done, and they're resting," said mother Aida Sandoval. "We're just going to take it one day at a time and let them catch up on their rest."
The twins and are expected to remain in intensive care for up to two weeks, hospital officials said.
Following such surgeries, the first 72 hours are typically the most critical, said Dr. James Goodrich, director of pediatric neurosurgery at Children's Hospital at Montefiore in New York. Goodrich has successfully performed seven cranial separations of twins joined at the brain.
"That's the window. That's when the worst stuff happens," he said, citing infections, bleeding and other complications. "If you make it through without any serious consequences, you're not out of the woods," he said, but odds of survival improve.
As few as one of every 200,000 births results in conjoined twins. About 50 percent of such twins are born stillborn, and 35 percent survive only one day, according to the University of Maryland Medical Center.
Only a few hundred surgeries have been performed successfully to separate conjoined twins. Stanford doctors had calculated a 30 percent chance that one or both twins wouldn't make it through the operation.
About 40 family members gathered at the hospital with the parents to lend support and talk about the twins.
"They've always been two little people emotionally," said one of the twins' sisters, Esmeralda, 25, who celebrated with a teary-eyed smile. "It's the physical part that's difficult to grasp."
The couple's oldest daughter, Aniza, credited her parents' level-headed strength for pursuing the operation.
"Despite everything they've been told - the percentages of life and death - they stayed positive throughout their whole journey," she said. "It only means that the rest of their future, our future as a family, will always be positive and looking at the glass half-full."
PHOTOS: 2-year-old conjoined twins separated in successful surgery
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Lucile Packard Children's Hospital Stanford via AP
In this Dec. 12, 2016, photo provided by the Lucile Packard Children's Hospital Stanford, formerly conjoined twin girls reunite for the first time since surgery with their parents.