Two-year-old conjoined twins Angelina and Angelica Sabuco were separated successfully on Tuesday during a 10-hour surgery at Stanford University's Lucile Packard Children's Hospital and are expected to fully recover.

The surgery consisted of two steps. First, the separation which began at 6:30 a.m. and ended shortly after noon, and later surgeons reconstructed the girls' chest walls, abdominal muscles and skin where they were joined, according to the Associated Press.

"The long-term prognosis is that we would expect a happy, healthy set of girls. We don't see any barriers to a complete recovery," the lead surgeon, Dr. Gary Hartman, said after the surgery was completed, according to AP.

Separation surgeries of conjoined twins occur about six times per year in the United States.

Angelina and Angelina were classified as thoraco-omphalopagus because they are joined at the chest and abdomen. Their livers, diaphragms, sterni (breast bones), chest and abdominal wall muscles are fused. They have separate hearts, brains, kidneys, stomachs and intestines, according to the Hospital.

Lead surgeon Hartman had said he considered dividing the liver to be the riskiest part of the procedure because of the possibility of severe blood loss, but that went smoothly.

"We were able to close the abdominal muscles without a graft, and the chest closure also went better than we anticipated," Hartman told AP.