The hospital said it had separated the two-year-old twins joined above the nape of their necks, in what’s believed to be the first successful operation of its kind.

The girls, Ervina and Prefina, were joined since birth, with their cranium and much of their venous system in common, ANSA reported.

They were joined in a very rare condition, sources said, and had different personalities despite sharing cerebral functions: Prefina being vivacious and playful with her sister Ervina more serious and quietly observing.

After more than a year’s preparation, the girls were subjected to three extremely delicate operations and separated on June 5, in an 18-hour operation involving 30 doctors and nurses.

A month on, they are said to be doing well.

Video images of a hospital party given for their second birthday with their mother on June 29 showed the girls, their heads wrapped in protective bandages, gesticulating and grabbing at their birthday cake.

The hospital cautioned that the risk of infection was still present and the girls would have to wear protective helmets for a few months.

 But post-operative controls showed that their brains were “intact”, adding that they will have the opportunity to grow normally and “lead a normal life, like all girls of their age”.

The two sisters from Bangui, Central African Republic, were brought to Italy in September 2018 after the hospital’s president, Mariella Enoc, met the twins and their mother at a medical centre where they were born.

They underwent three operations, the first in May 2019, the second in June 2019, and the third in June 2020, ANSA reported.

The greatest challenge facing the team of specialists  –  including neurosurgeons, anaesthesiologists, neuroradiologists, plastic surgeons, engineers, and physiotherapists  –  was the shared network of blood vessels bringing blood from the girls’ brains to their hearts, the hospital said in a statement.

It was the fourth time the hospital had operated on conjoined twins in its history.

Twins conjoined by the skull are extremely rare, or approximately one case every 2.5 million live births, the hospital said, adding that in Europe in the past 20 years only two cases of separating twins joined at the top of their skulls had been successful.