Dr. Maria Siemionow was getting ready for bed a couple weeks ago when she got the telephone call she had been awaiting for 20 years.

The Cleveland Clinic plastic surgeon was told that a woman had died and her family was willing for her to be the donor for the first face transplant in the United States.

And that meant that Dr. Siemionow's patient, a woman who had lost most of the middle of her own face several years ago in a violent trauma, might have the chance to regain some semblance of a normal life.

By the next afternoon, a team of surgeons had assembled at the clinic to do the historic operation.

They started by removing 80 percent of the donor's face, from her lower eyelids down through her upper lip. As they worked, they sometimes checked their progress against an exact 3-D model of the recipient's face, which had been made from computerized X-ray scans.

In an adjoining operating room, another team began to remove the scar tissue that had covered the concavity in the center of the recipient's face.

For years, she had lived with vision in only one eye, no cheekbones, no nose, no upper jaw and no upper lip. She could see only dimly, could not eat without a feeding tube, could no longer smell and had difficulty communicating.

She was courageous enough to go out in public, Dr. Siemionow said, but "she often suffered humiliation. People called her names. Children were scared of her and ran away. She was very brave in facing the world but it became very difficult for her to go outside her home."

Now, Dr. Siemionow and her colleagues were hoping to change all that.

Eleven hours after surgery began, the doctors positioned the donor's face over the same parts of the recipient's face and began attaching skin, muscle, veins, arteries, nerves and bone.

It was an exacting and exhausting procedure, said Dr. Daniel Alam, one of the principal plastic surgeons on the case.

The team had to connect five major blood vessels, two sets of nerves, with intervening nerve grafts, all of the muscles and bone, and in the end, "it was like a jigsaw puzzle you had to fit into the appropriate position and put together."

With operations like an appendix removal, Dr. Alam said, surgeons do about the same procedure on every patient. But in these kinds of transplants, he said, "it becomes like an artistic project for each individual patient."

By 4:30 p.m. on the day after they started -- 22 hours all told -- the surgical teams were done.

Later, as she began to emerge from the anesthetic, one of the first things the patient did was run her hands over her face, confirming that she had a nose, a jaw and cheeks for the first time in years.

Then, she gave the team a thumbs-up sign.

The procedure in Cleveland is the world's fourth face transplant and the largest in skin area to date. The others were done on a woman mauled by her dog in France, a man in Europe with a disfiguring congenital disorder and a Chinese man who'd been attacked by a bear.

Face transplants are known as "composite tissue" transplants because they involve skin, muscle, nerves and bone. The other type of composite transplants in recent surgical history have been hand and arm transplants, about 40 of which have been done worldwide.

Experience with those procedures has shown the first month is the critical period for seeing whether the person's body will try to reject the transplanted tissue.

So far, the woman in Cleveland has had no rejection. And the hand and arm transplant history shows that if patients can get past that first month and take their immunosuppressant medication faithfully, they are able to have functional transplants for years afterward.

Unlike many organ transplants, face transplants are not life-saving, but instead enhance quality of life. For that reason, some medical ethicists have questioned whether they should be done at all, and have asked whether the risks of rejection or future infections and cancer from taking immunosuppressants outweigh the benefits.

The Cleveland Clinic team argued strongly that in cases of severe disfigurement and interference with normal functioning, the benefits do outweigh the risks.

The clinic's fact sheet also noted that every face transplant candidate must have enough viable skin elsewhere on the body to replace the transplanted tissue if it is rejected.

Dr. Eric Kodish, the team's ethicist, noted that the clinic would never do a face transplant for "cosmetic enhancement," and hopes no one else would ever attempt one.

Even though the clinic has emphasized that from the beginning, Dr. Siemionow said that after the clinic got institutional approval four years ago to do face transplants, some of the inquiries they received were from people with minor facial scars or blemishes.

"They were thinking we would do this to beautify them," she said in amazement.

For the same reason, Dr. Kodish said the recipient would never be shown a photograph of the donor's face, because it would suggest the donor's appearance was a factor.

Besides, the doctors noted, face transplant recipients are unlikely to look like the donor because of their underlying muscle and bone structure, and particularly so if they have been disfigured.

Neither the donor family nor the recipient wanted personal details revealed, so the doctors would not talk about how the donor died or what kind of trauma the recipient had experienced.

The donor was a woman of the same race, Dr. Siemionow said, and was roughly the same age. She also donated her kidneys and liver to other patients.

The transplant recipient now has months of rehabilitation ahead of her. Nerves in the transplanted tissue will grow about a millimeter a day, and within three to six months, she should regain significant feeling and motor control in the new face.

"There will be a lot of work to do," Dr. Alam said, "getting her nerves to function, learning how to smile, to eat, and even learning how to blink with hybrid eyelids, because her upper eyelids are hers and the lower ones are from the transplant."

After some months go by, perhaps the patient will be ready to venture out again, said Dr. Siemionow, who has been doing research on these kinds of procedures for two decades.

"You know, people with normal faces don't understand what it's like, because nobody looks at them with suspicion or is scared of them," she said.

"Patients who are disfigured just want to look normal. One candidate said to me that her greatest gift would be just not to stand out."