Surgeons today described the first face transplant in the United States, a painstaking 22-hour operation to stitch most of a dead woman's face onto a recipient so horribly disfigured she was willing to undergo the risky surgery in the hopes of being able to smile, smell, eat and breathe normally again -- and go out in public without frightening children.

In a procedure done sometime in the past two weeks, the 30-member Cleveland Clinic team replaced about 80 percent of the patient's face -- essentially recreating the entire middle of her face including her lower eyelids, nose, cheeks, and upper jaw, along with supporting the bones, muscles, nerves and arteries.

The operation, transferring everything except the upper eyelids, forehead, lower lip and chin, marks the first time the controversial procedure has been performed in North America and the most extensive face transplant yet.

"I'm very proud and emotional today to share with you what we finally did," said Maria Siemionow, the reconstructive surgeon who led the team. "The patient is doing well . . . I must tell you how happy she was when with both her hands she could go over her face and feel that she has a nose, feel that she has a jaw."

To protect the privacy of the donor and the recipient, no details about either were released, other than a statement from the recipient's family.

"We never thought for a moment that our sister would ever have a chance at a normal life again, after the trauma she endured," the statement said. "There are tears of joy, and tears of pain that it took one to pass for one to have a life."

Other experts praised the operation, saying it was a prelude to many other similar surgeries to help thousands of patients mutilated by accidents, tumors and other trauma.

"This is wonderful advance," said L. Scott Levin of the American Society of Reconstructive Transplantation, noting that hospitals in North Carolina, Massachusetts and Tennessee were already planning similar surgeries. "The entire North American reconstructive surgery community is on the precipice of jumping into this in a big way."

Several surgeons and bioethicists said many of their early reservations about the procedure have eased since the first one in France three years ago. But a host of thorny questions remain, and some continued to question the operations, saying it remains far from clear how long the graft will last and whether the benefits outweigh the risks.

"A graft loss would leave the patient with an open wound across most of the face," said Carson Strong, a professor of human values and ethics at the University of Tennessee College of Medicine. "The patient clearly would be worse off than before the attempted face transplant."

The researchers acknowledged the procedure poses concerns for society, including fears it would become used for purely cosmetic purposes or even to steal someone's identity.

"We will do everything in our power to prevent the misuse of this important advance," said Eric Kodish, a bioethicist who was on the team.

When the first partial face transplant was performed in France on a woman who had been mauled by her dog, the news set off an international firestorm. Another face transplant was subsequently performed on a Chinese farmer who had been attacked by a bear, and then another in France on a man disfigured by a genetic condition.

The transplants are controversial because they are aimed at improving a patient's quality of life rather than saving it, raising questions about whether the procedures are worth the risks, which include potentially life-threatening side effects from powerful immune-suppressing drugs patients need for the rest of their life.

But despite a difficult recovery, the first recipient, Isabelle Dinoire, gradually regained normal skin sensation and control of her facial muscles and has reported that the operation transformed her life.

"I've become convinced a competent team could manage this," said Arthur Caplan, a University of Pennsylvania bioethicist. "I think the microsurgery, the cosmetic surgery, the management of the immunosuppression has gotten to the point where trying this, given the desperation of the patients, makes sense."

Others said they were reassured that the transplanted tissue does not resemble the donor, as had been feared.

"When we think of face transplants we think it's going to be someone else's face on another person -- a Frankensteinian kind of thing," said Jeffrey Kahn, a University of Minnesota bioethicist. "In fact, that's not what happens. It's the underlying structure of the recipient that really determines what it's going to look like."

Others, however, remain uncomfortable.

"For a patient who needs a heart transplant, not receiving the transplant is going to be fatal. That isn't the case for a patient who needs a face transplant," Strong said.

Siemionow and her colleagues defended the procedure, saying it was based on more than 20 years of research, including practice on animals and cadavers. Dozens of candidates were carefully screened, subjecting them to intensive psychiatric testing before selecting the first patient. The woman finally selected had undergone several reconstructive procedures but remained unable to eat, speak or breathe normally.

The procedure began at 5:30 p.m. sometime in the past two weeks after the donor's family agreed. After confirming the two women's tissues were a good match, surgeons carefully began to remove the donor's face at about 8 p.m., working for more than nine hours.

In an adjacent room, a second team prepared the recipient. The facial tissue was transferred to her operating room just past 5 a.m. the next morning. For nearly three more hours, surgeons connected the patient's blood vessels to the facial graft vessels to restore circulation. When the tissue turned pink, they knew they had succeeded. The multidisciplinary team of surgeons then continued to work in shifts to allow some to rest, sleep and confer, completing the operation at 4:30 p.m.

"I think it's the most complex surgical procedure ever performed," said Frank Pupay, who was part of the team.

"It's very exciting," said Bohdan Pomahac, who is planning a face transplant at Brigham & Women's Hospital in Boston. "It's great for the field."

Doctors stressed that the patient has a long, potentially treacherous road ahead. They are carefully monitoring her for any signs of rejection. Assuming no complications occur, doctors expect that the swelling will subside after a couple of months and that feeling will return to her face within about six months. With intensive physical therapy, function should return within about a year. Eventually, the woman's destroyed right eye will be replaced by a prosthetic device. If the graft fails, doctors said it would be replaced with a skin graft from different parts of her body.

"If it did fail and the face was rejected, it would be an almost unimaginable situation," Caplan said. "Your face would be sloughing off. You can't eat. You can't breathe."

Others said the transplantation of a face could cause people to reevaluate how they perceive their own identity and those of others.

"People have a lot of very deep-seated psychological anxieties related to receiving the face of another," said Carla Bluhm of Allegheny College, who co-authored an upcoming book exploring the issues, titled "Somone Else's Face in the Mirror." "How deeply can it disrupt your sense of who you are? And what are those consequences? We simply don't know yet."

Another issue is whether people who sign organ donor cards should be advised that in addition to their heart, kidney and other organs, their faces might also be used for transplants.

"When I signed my organ donor card I wasn't thinking about someone taking my face," Caplan said. "I doubt most Americans do. Do you also have to have the family consent? They bear the emotional consequences of seeing their loved one's face on someone else. Even if it looks different it will remind them of you."

But Siemionow said she hoped the operation would eventually help many others.

"There are so many patients . . . who are hiding from society because they are afraid to go to the grocery store, they are afraid to go to the street because they are called names and they are humiliated," Siemionow said. "You need a face to face the world."