It's not the first face transplant, but it is the world's most extensive.

In a 26-hour operation, Dr. Eduardo Rodriguez and his 150-strong team at NYU Langone Medical Center in the United States gave a new face to a volunteer firefighter who was injured in a burning house 14 years ago.

The firefighter, Patrick Hardison, was 27 years old when he entered the burning house to look for a woman. The roof collapsed and Hardison suffered third-degree burns to his head, neck and torso.

Dr. Rodriguez says Hardison's face was "one big scar."

Hardison spent time at a burn center, where doctors used skin from his legs to cover his head. But he had lost his ears, lips, most of his nose and almost all of his eyelid tissue.

He underwent 71 surgeries in the intervening years until Hardison's friend contacted Dr. Rodriguez, who had performed a similar face transplant at the University of Maryland in 2012. Hardison was put on a waiting list for a donor in 2014.

That donor was 26-year-old David P. Rodebaugh, who had died in a cycling accident.

Complex operation

Then in August of this year, Rodriguez and his team performed the mammoth surgery.

It was a simultaneous operation, with Hardison on one operating table and the deceased cyclist on another.

They slit the skin at the back of the donor's head before peeling it forward and then draping it on Hardison's head.

Four bone segments were attached to Hardison's skull. They will act as anchors to hold the face in place.

It's been three months since the operation, and Hardison's face is still swollen.

But with his new eyelids and more surgery to come, Hardison hopes to regain full sight - and to see his children with his own eyes for the first time since 2001.

Growing field in surgery

Hardison's face transplant will not only change his life, but will also help further the field in surgery.

The first partial face transplant was carried out in France in 2005 on a woman who had been attacked by her dog. In 2010, Barcelona's Vall d'Hebron University Hospital performed the world's first full face transplant on a man who lost his nose and whose jaw and cheekbone were deformed in an accident. In March, the same hospital reconstructed two thirds of the lower face of a man disfigured by a disease.

These operations - once thought unthinkable - are now becoming common.

For now, though, Hardison's own progress will see him remain on immune suppressant medication for the rest of his life. But he is slowly returning to a life he once knew.

Early next year, he will likely undergo further surgery on the tissue around his eyes and his lips.