Conjoined twin girls, age 2, undergoing rare separation surgery

A nine-hour surgery is scheduled Tuesday for 2-year-old sisters, a rare and tricky medical procedure that would finally allow the little girls to roam free without the other tagging along.

Angelica and Angelina Sabuco are conjoined twins who are attached at the chest and abdomen.  

The girls have separate hearts but their livers are connected, making the scheduled surgery at Lucile Packard Children's Hospital at Stanford a complex procedure, the hospital reported.

"Our expectation is we will have two healthy girls at the end of the procedure, although we recognize it's a fairly risky procedure," the lead surgeon, Dr. Gary Hartman, told the San Francisco Chronicle.

Conjoined twins are rare and surgeries are even more scarce because most of the children don’t survive until birth or die shortly thereafter, the hospital reported. Separation surgery is performed about six times a year in the United States.

For Angelica and Angelina, the surgery is expected to give them an independence they’ve never known.