After 27 hours of surgery—and 13 months joined together—twin boys Anias and Jadon McDonald were presented to their parents separately for the first time on Friday morning. The surgery took place at the Children's Hospital at Montefiore Medical Center in the Bronx, led by Dr. James Goodrich, the leading expert in "craniopagus surgery," that is, separating conjoined twins who are attached at the head. While the proceedure carried the risk of death and brain damage for either or both boys, studies have shown that twins joined at the cranium who are not separated die of medical complications by the age of two. This is the seventh—and longest—craniopagus separation surgery performed by Dr. Goodrich and only the 59th such surgery performed in the world since its conception in 1952. The McDonalds and Montefiore invited CNN to follow and document the boys' surgery.