Doctors plan to perform the first in a series of high-risk surgeries to separate 3-year-old twin girls joined at the head.
Doctors hope to separate Tatiana and Anastasia Dogaru, who were born in Italy but are of Romanian descent, through several surgeries in about six months. Without separation, the twins risk dying in early childhood.
In the daylong procedure Wednesday, surgeons said they will begin at the girls' scalps and slowly make a wedge where the twins' skulls are joined. A rectangular bone flap will be removed and reinserted at the end of the surgery.
The procedure will give neurosurgeons their first real glimpse of the girls' brains. The medical team practiced the procedure on a model designed from images.
How much separation is accomplished Wednesday depends on the complexity of blood vessels, tissue and bone connections. A spokeswoman for University Hospitals' Rainbow Babies & Children's Hospital said doctors may not be able to provide a medical update until Friday.
The girls' parents, the Rev. Alin Dogaru, a Byzantine Catholic priest, and Claudia Dogaru, both 31, have said they view the separation surgeries as the girls' best hope. They arrived in Cleveland on April 6 after 2 1/2 years in Dallas.
Twins born joined at the head known as craniopagus twins are rare, occurring in about one in 2.5 million births. The top of Tatiana's head is attached to the back of Anastasia's, and they have never been able to look directly at each other.
Last month, doctors succeeded in establishing independent blood flow in the twins by inserting small coils into veins in their brains. That was viewed as a prerequisite for separation surgery.
Dr. Alan Cohen, chief of pediatric neurosurgery, and Dr. Arun Gosain, chief of pediatric plastic surgery, were confident a team of up to 50 specialists was ready for the Wednesday operation. Surgeons spent Saturday and Monday in practice sessions.
Bleeding in these procedures is a major risk. Other potential complications include infection, stroke and a build up of fluid in the brain, doctors say.