Doctors in Ohio will start surgery on 3-year-old conjoined twins Wednesday.
Tatiana and Anastasia Dogaru, ethnic Romanians born in Rome, arrived in Cleveland on April 6 after 2 1/2 years in Dallas. Without separation, the twins run the risk of dying in early childhood.
Twins born joined at the head - called craniopagus twins - are extremely rare, occurring in about one in 2.5 million births. The top of Tatiana's head is attached to the back of Anastasia's.
Last month, doctors at University Hospitals Rainbow Babies & Children's Hospital succeeded in giving independent blood flow to the twins by inserting a coiled wire device into veins in their brains, which share tissue.
The procedures were designed to divert blood flow that had been shared by the two brains so most of the blood from each girl's body would go to only her brain.
A team of more than 30 doctor and nurses will work to separate the girls, including neurosurgeons who will perform the actual separation and plastic surgeons who will repair the girls' skulls, skin and faces.
Their parents, the Rev. Alin Dogaru, a Byzantine Catholic priest, and Claudia Dogaru, both 31, have said they view the medical procedures as the best hope for the two girls.