As Jaga and Balia, conjoined twins from Odisha who spent over two years at AIIMS here undergoing complicated surgeries for separation of their heads left for their hometown on Friday, Union Health Minister Harsh Vardhan lauded the team of doctors for the "rarest of the rare" surgery and asserted that it was the "first successful craniopagus conjoined twin separation surgery" in India wherein both the children survived.

Harsh Vardhan said in the last 50 years, only 10 to 15 children worldwide have survived after the surgical separation procedure.

"This is an extremely rare condition seen in one in 25 lakh live births and any kind of surgical intervention in this condition has 75-80 per cent risk to life to one or both children," the health minister said.

Professor of Neurosurgery at AIIMS Dr Deepak Gupta, who led the surgery termed it extremely complex and challenging as the twins "shared venous return (circular sinus) and were totally fused with each other at the head".

Their surgical separation required meticulous and detailed planning, he said. About the present condition of the twins, Dr Gupta said, "Jaga is developing well in all domains of neuropsychological assessment. He is gaining weight and can join school immediately after returning home."

After their arrival at the Odisha city on Saturday, the twins will be admitted to the Srirama Chandra Bhanja Medical College and hospital there for further medical assistance.

Balia remains neurologically disabled and is being fed through a special tube. But he is breathing on his own, the neurosurgeon said, adding he requires long-term rehabilitation care.

The separation of their heads took place in two stages. The first stage surgery, lasting 25 hours, involved creating a venous bypass on Balia and partial brain separation from Jaga. It was conducted on August 28, 2017.

The final separation of the children was done on October 25 and this operation lasted 20 hours. Skin grafting and minor neurosurgical procedures were performed on the children to cover skin defects over the next few months.

During the final surgery on October 25, Jaga suffered a cardiac arrest, but he was successfully revived after 15 minutes. The two children stayed in the private ward of AIIMS's Neurosciences Centre for the last two years.