Charities estimate there are thousands of migrant and refugee children in Greece who are in need of specialist care, but say the country is unable to cope with them.
We travelled to Athens and met a number of Syrian children needing treatment, including a burns victim requiring plastic surgery and a paraplegic teenager who needs a life-saving kidney operation.
Hanan Ashegh of the UK charity Goodwill Caravan told Sky News: "The Greek people have been wonderful but because there's such an exodus of refugees coming to Greece the medical services are over-stretched.
"There's nothing here for the migrants - not because the country doesn't want to help but because they are over-stretched.
"If we can get them help by bringing them to a country that can help them more than anyone can help them here that's something I will continue to try to do."
We met 13-year-old Najib Ali as he saw specialist consultants for the first time since his family arrived in Greece over a year ago.
Najib still has shrapnel in his spine. The family's home near the Syrian city of Homs was hit by a bomb; Najib was so badly injured he was left unable to walk.
He has been a paraplegic for four years - his family pushed him in a wheelchair across Syria then paid smugglers to take them in a dinghy to Europe in the hope they would find a doctor to help him walk again.
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His mother Faten said: "My son was a very happy boy.
"He liked to dance and was in a lot of dance competitions.
"My son used to be able to run, go out, eat.
"The first thing I thought after the strike was that he had died, that I would have to bury him.
"Thank God I found out he was alive.
"Then I was told he had lost all feeling beneath the waist and that he won't be able to walk, that he will always be exhausted.
"As a mum, it is torment because I am totally unable to do anything for my son."
Najib is in a wheelchair but doctors have discovered new problems: his blocked kidneys are like those of an old man and he is facing the prospect of kidney failure.
Neurosurgeon Stavropoulos Stavros said: "He's got a very serious kidney problem that needs to be dealt with pretty soon in order not to jeopardise his kidney function and end up on dialysis."
Goodwill Caravan is supporting Najib and many other migrant families, including Ibrahim Jbarra, his wife Manar and their six children.
The couple say their eight-year-old twin sons Omar and Mohammed are unrecognisable since a chemical attack in Raqqa in Syria.
Doctors in Syria told them the twins were the victims of a sarin attack, they say, although we cannot independently verify their claims.
Omar rolls around the floor like a toddler and has no speech.
Mr Jbarra said: "After the strike they changed.
"You can see what Omar is like - his actions aren't normal.
"The main thing with their conditions is the movement: they can't move properly.
"There are problems with his nerves, his body, there is even a slight drooling and foaming at the mouth without him knowing what he is doing, without any realisation."
Hundreds of thousands of migrants and refugees have passed through Greece but tens of thousands are trapped because borders to the rest of Europe are closed.
After a hard winter the days are getting warmer which makes survival easier for most people, but not for everyone.
We sit in the shade to meet an 11-year-old boy who cannot face direct sunlight.
Mannan suffered third-degree burns to much of his body and needs plastic surgery.
After fleeing conflict in Syria, fire broke out in his family's tent in a Greek migrant camp.
Mannan's mother Amina Arslan had to choose which of her children to try to rescue from the flames first. She saved her daughter Nathlya, sparing at least one child more serious injury.
Amina said: "In the pharmacy here they don't have the right medicine for Mannan. The doctors don't have the right equipment.
"So what's the solution? I don't know if there is a solution.
"God will decide what will happen."