Doctors at a US clinic will start interviewing potential recipients for the world's first face transplant in the next few weeks, after winning approval from the clinic's internal review board.
The medical team at the Cleveland Clinic in Ohio is led by Maria Siemionow, a 55-year-old surgeon who has spent years conducting research into face transplants, including experiments on animals and human cadavers.
"You want to choose patients who are really disfigured, not someone who has a little scar," she told Associated Press.
The procedure is intended to help patients whose faces are disfigured because of an accident or genetic fault. Many patients spend years enduring painful reconstructive surgery. It is a process that has been labelled "life by 1,000 cuts".
Proponents of face transplants argue that the procedure could remove the need for years of operations by applying a new sheet of skin in one operation. While the capability to perform face transplants has existed for years, nobody has attempted it. Teams of surgeons in Britain, France and the US have previously announced that they are close to performing face transplants, but concerns over the ethical implications of the procedure have halted or delayed their plans.
Although the Cleveland Clinic team has won approval from an internal review board, critics say an independent review board should determine whether the procedure can go ahead.
Last year a team at the University of Louisville in Kentucky, which had successfully transplanted a human hand, decided not to go ahead with face transplants after examining the ethical issues. "At stake is a person's self-image, social acceptability and sense of normalcy," wrote Osborne Wiggins, a philosophy professor and clinical investigator at the university, in the American Journal of Bioethics.
In the same journal, Carson Strong, a bioethicist at the University of Tennessee, wrote: "It would leave the patient with an extensive facial wound with potentially serious physical and psychological consequences."
But Dr Siemionow's team argues that the possible gains are worth the risk involved. "Really, who has the right to decide about the patient's quality of life?" she asked. "It's very important not to kind of scare society ... We will do our best to help the patient."
The operation is expected to last up to 24 hours hours. A "skin envelope" from a donor is attached to the recipient using one or two pairs of veins and arteries on either side of the face. About 20 nerve endings would also be attached.
The recipient should look similar to the way they did before the operation, the Cleveland Clinic tells potential donors and patients. This is because the skin is grafted on to existing bone and muscle, which determine the shape of a face. Similarly, expressions and facial characteristics are determined by the brain, and are not the product of facial tissue.
Other researchers suggest, however, that the final result will resemble a combination of the recipient and the donor.
Opponents are most concerned about the possibility of rejection of the transplanted tissue and cultural and ethical problems. They are also concerned that the procedure, if successful, could be exploited for cosmetic surgery. Should the recipient's body reject the transplant, it raises the possibility that the patient will be left worse off than before.
Many critics also question whether a person already traumatised by facial disfigurement would be equipped to cope. Although the Cleveland Clinic tells prospective recipients that it will do its best to shield their identity, it concedes that the press will probably discover it. The clinic also tells patients that the risks are so unknown it does not think informed consent is possible.
Dr Siemionow and her team expect to interview five men and seven women in the coming weeks. But she warned that applicants should not have unrealistic expectations about the results.
"It's not a shopping mall," she said. "They need to rely on our judgment. If they are starting to shop, they are not good candidates."
How the operation works
How would doctors carry out a face transplant?
Surgeons would need to take all the skin from the donor's hairline to jawline and from ear to ear. They would also save the nose, mouth, lips, eyebrows and eyelids and ensure that the muscles, the layer of fat and the nerves were still attached. Along with eight blood vessels, each element of the donated face would have to be carefully reconnected in a surgical procedure that could last up to 24 hours.
Who would the patient look like?
Not like the donor. The skin tone, texture and hair colour of the donor would be transferred but the patient's own bone structure would determine what their new face would look like.
How long would it take to recover?
The recipient of a new face might have to stay in hospital for several weeks. In addition, patients would have to take drugs to suppress their immune system (which would otherwise attack the new face as it is foreign tissue) for the rest of their lives.
Have we been here before?
In 2004, a team from the University of Louisville in Kentucky submitted a request to their ethical committee to carry out what would have been the first face transplant in the world. Two years before that, scientists in Britain had discussed the ethics of such operations amid concerns that the first transplants would be carried out later that year.
