The nation's first near-total face transplant has been done on a woman at the Cleveland Clinic, the hospital announced this morning.

Reconstructive surgeon Dr. Maria Siemionow replaced 80 percent of the woman's facewith that of a dead female donor in an operation a few weeks ago.

The patient's name and age were not released. The hospital plans a news conference Wednesday to give details.

The world's first partial face transplant occurred in France three years ago on a woman who had been mauled by her dog. Two others have been announced since then — a Chinese farmer attacked by a bear and a European man disfigured by a genetic condition.

The nature of the injuries or disfigurement that prompted the Cleveland case are not yet known. Such transplants are controversial because they are aimed at improving a patient's quality of life rather than saving it and require recipients to take immune-suppressing drugs for the rest of their life.