Neev and Nelly are twin sisters who have survived years beyond what doctors predicted.

The 18-year-old Siamese twins, from Amsterdam, are connected at the head, but each has their own brain and body. When they were born, doctors said they would not live to be 10 years old.

Neeva and Nelly cannot be separated because they share a main artery in their heads that keeps them alive. But the twins are doing very well and say they don’t want to be separated.

As Craniopagus twins, the girls are a medical phenomenon, accounting for just two to six percent of conjoined twins worldwide.

They have created their own YouTube channel and their own Instagram page to raise awareness of their condition and show them that they are much more than just “disabled girls”. Neeva and Nelly have an unbreakable bond.

“When we were babies, everyone thought we were going to die. But we are still alive. We are 18 years old and we stand on our four feet”said Nelly as quoted by dailymail.

“Our bodies are separated, but we are connected at the head. Everyone thinks we can read each other’s minds. But we can not. We have our own thoughts. It means we can both do whatever we want like walking and talking.”added Neeva.

Due to the lack of medical resources where they were born in Suriname, South America, the girls had to relocate to the Netherlands for more urgent and specialist care. But despite their parents’ wishes, they cannot be separated.

Their brain’s blood supply is so entangled that it would be deadly to attempt to separate them.

The twins’ sister, Rosianne Kolestein, 24, said: “We moved to the Netherlands because there was a small chance of separating them at the start. That’s what our parents wanted, they wanted a better life for them. Life in Suriname was difficult. People started to distance themselves from our family, they thought their condition might be some kind of voodoo.

But the doctors did more tests and realized that it was not possible to separate them. They share important blood vessels and veins. They have an artery that keeps them alive. To separate them, it will have to be cut, which would kill them”.

Craniopagus twins can be separated in a series of complicated operations, and a number of cases have been reported in the media.

However, the risks of separation are so high that they can unfortunately cause death during or shortly after the operation, as well as brain damage.