The first child to have pioneering surgery to rebuild his windpipe with his own stem cells is doing well and is back in school.
Ciaran Finn-Lynch, who is now 13, had the ground-breaking surgery at London's Great Ormond Street Hospital in 2010.
Using Ciaran's own stem cells meant his immune system would not reject, and attack, the organ.
His surgeons said things were going well so far and that Ciaran could live the life of a normal teenager.
He was born with long-segment tracheal stenosis, which causes breathing difficulties. His lungs collapsed on the day he was born and he had major surgery to reconstruct his airways when he was six days old.
Metal tubes were used to hold his airways open, but in 2009 one caused huge amounts of bleeding when it damaged the main blood vessel coming out of the heart.Spray-on stem cells
It was at this stage surgeons tried a pioneering operation. Instead of growing a new windpipe, they took a donor windpipe and stripped it of all the donor's cells. What was left was a three-dimensional web of collagen fibres which was transplanted into Ciaran.
Meanwhile, stem cells, which can be collected from bone marrow, cord blood and dental pulp (the inside of the tooth) can become any other type of cell, from nerve to skin cells. Ciaran's stem cells were taken from his bone marrow. These were then sprayed onto the newly transplanted windpipe.
The surgery had been tried once before in Spain, in 2008, on a 30-year-old woman, but Ciaran was the first child.
He has been monitored for the past two years and the details have been published in the Lancet.
There has been no sign of the transplant being rejected and "at last follow-up the boy was alive, growing, had normal lung function, and had returned to school".
Martin Elliott, director of the national service for severe tracheal disease in children at the hospital, said: "The ideal outcomes for tracheal transplants in children are normal airway and lung function, good general growth, a decent quality of life, and no further surgical interventions.
Surgeon, Prof Martin Birchall, speaking in 2010 said: "It could replace transplantation" and goes on to say that "The treatment offers hope to many whose major airways were previously considered untreatable or irreplaceable."