US: Doctors at a US clinic will start interviewing potential recipients for the world's first face-transplant in the next few weeks, after approval from its internal institutional review board.
The medical team at the Cleveland Clinic in Ohio is led by Prof Maria Siemionow, a 55-year-old surgeon who has spent years conducting research into face-transplants, including experiments on animals and human cadavers.
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.
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. 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. The operation is expected to last up to 24 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. 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.
Should the recipient's body reject the transplant, it raises the possibility that the patient will be left worse-off than before.