Eight specialists took part in the 22-hour operation
Details have emerged of the first almost-total face transplant performed by surgeons in Cleveland, Ohio.
Eight specialists transplanted bone, muscle, blood vessels and nerves in the 22-hour operation, doctors said.
They did not name the female patient, but said an injury several years ago had left her without an eye, most of her nose and her upper jaw.
The transplant was the fourth to have been carried out after two operations in France and one in China.
Dr Maria Siemionow, the reconstructive surgeon in charge of the operation, said 80% of the woman's face was replaced with that of a dead female donor.
'Face the world'
The patient had been disfigured to the point where she could not eat or breathe on her own, doctors involved in the transplant told a press conference at the Cleveland clinic on Wednesday.
They said they hoped the surgery, performed two weeks ago, would allow her to regain both the ability to smile and her sense of smell.
Most of the woman's face was replaced with that of a dead female donor
"We need the face to face the world," said Dr Siemionow.
"We know that there are so many patients there in their homes where they are hiding from society because they are afraid to walk to the grocery stores, they are afraid to go the street."
"Our patient was called names and was humiliated."
Doctors said the woman had responded well to surgery and her body was showing no signs of rejecting the new face.
After such a transplant procedure, patients are required to take medication for the rest of their lives, suppressing their immune system to prevent the transplanted skin being rejected.
The world's first face transplant took place in France three years ago, on Isabelle Dinoire, a woman who had been mauled by her dog.
Dr Maria Siemionow spoke of her pride at the success of the operation
Surgeons used donor tissue to replace her nose, mouth, lips and chin, and Ms Dinoire has said she is satisfied with the results.
Since then, operations have been carried out on a Chinese farmer who was mauled by a bear while trying to protect his sheep, and on a French man disfigured by a genetic condition.
After such transplants, the new face does not look like the donor because its shape is altered by the muscles and bones of the patient's face.
But some experts have warned of possible psychological side-effects which may include remorse, disappointment, or grief and guilt towards the donor.