On Thursday, Brigham and Women's Hospital in Boston witnessed the second face transplant operation performed in the United States and the seventh in the world.

The surgeon who led this surgery said that he and his team are "cautiously optimistic" over the recovery of the patient.

"So far he is doing very, very well," said Dr. Bohdan Pomahac.

At a press conference, on Friday, Dr. Pomahac revealed that the patient had not undergone immunosuppressant therapy before the operation became necessary; a departure from the hospital's previously stated policy on facial transplantation. But the doctors and ethicists are of opinion that the move was justified in this case was made in order to liberalize the rule so that more patients, in need, could be helped.

"We felt it was a natural progression of the program to extend [the operation] to the patient who is not on immunosuppressants," said Pomahac.

Dr. Joseph McCarthy, director of the Institute of Reconstructive Plastic Surgery at New York University's Langone Medical Center, said that the side effects of immunosuppression may be an even more a cause of concern than the surgery itself.

"You are really committing the patient to a lifetime of treatment to prevent rejection," he said.