Twins conjoined at the skull have been successfully separated in a surgical marathon lasting more than 16 hours.
Jaden and Anias McDonald were born with the condition which occurs only once in every 10 million live births.
The surgery was led by Dr James Goodrich, a leading expert in craniopagus surgery, CNN reports.
It was the seventh separation surgery performed by Dr Goodrich, and just the 59th such operation in the world since 1952.
The complex surgery was laden with risks, including death and the possibility of long-term brain damage for one or both of the boys.
Neurosurgery nurse Bindu Peter detailed the procedures: “We are doing craniopagus separation, fasciocutaneous scalp flaps, removal of expander, cranioplasty with bone graft, possible skin graft or use skin substitute, adjacent tissue transfer scalp, possible insertion of tissue expanders, possible insertion of wound closure device.”
Shortly after the twins came out of surgery, their mother Nicole McDonald posted an update on Facebook, describing how an exhausted Dr Goodrich had emerged from the operating theatre to report: “Well, we did it.”
McDonald described further details of the surgery, including the separation of a small area of brain tissue and a period of uncertainty where Anias’s blood pressure and heart rate fell dangerously.
She added: “It’s a bit surreal… I should feel so happy… TWO SEPARATE BABIES!!! And yet I ache with the uncertainty of the future. I didn’t cry until the surgeons left the room. I was barely able to even utter the words ‘thank you’ because of the pit that still sits heavy in my stomach.
“We are standing on the brink of the great unknown. The next few months will be critical in terms of recovery and we will not know for sure how Anias and Jadon are recovering for many weeks.”
The brothers are being treated at the Montefiore Hospital in the Bronx, New York.