WEDNESDAY, Dec. 28 (HealthDay News) -- Full face transplants were once the stuff of science fiction, but not anymore.

So far, 18 such transplants have been done worldwide, and U.S. surgeons describe the intricate procedures in the Dec. 28 online edition of the New England Journal of Medicine.

The article details the stories of three face transplants that were performed at Boston's Brigham & Women's Hospital in 201l, including the much-publicized case of Charla Nash, who lost most of her face in a chimpanzee attack.

While some technical challenges remain, surgeons say they are getting better and better at performing face transplants.

"We don't know how common or rare this operation will be, but it is here to stay," said Dr. Bohdan Pomahac, the director of the plastic surgery transplantation program at Brigham & Women's. He was the lead surgeon on all three cases described in the journal report.

These lengthy and complex surgeries are reserved for individuals with severe facial deformities, but as techniques and technology improve, transplants could become an option for patients with lesser degrees of facial deformity.

Who's a candidate? According to the doctors, prospective recipients first undergo extensive medical and psychological evaluation. If they are deemed to be appropriate candidates, surgeons then begin their search for suitable donors and start to plan the surgery.

Each operation is unique and can take more than 20 hours to complete. In general, surgeons will first remove any non-viable or injured tissue from the face transplant recipient. The healthy tissue, once procured from suitable donor, is then attached. This is not a simple task -- surgeons must restore blood flow, reattach nerves, muscles and bony structures, and then reconnect each layer of the new face.

Even so, "the hardest part is the recovery of the donor face," Pomahac said. After the transplant is complete, surgeons must be on the lookout for any signs of rejection and other side effects, such as infection. These risks are highest during the first 24 hours after surgery. "There can be clotting in the vessels that are re-connected, and we use high doses of immune suppression for a first couple of days so the patient is more susceptible to infection," he explained.

In the beginning, the patient's new face is swollen and has no motion. "Most of the swelling goes down in six weeks and then you regain motor function in three to six months," he said. Many of these patients are eating within a few days. "They get better and better each time we see them," he said.

Unlike in the movies, the patient does not wake up with the face of the donor, Pomahac stressed. Instead, the new face is more of a hybrid between donor and recipient. "It is surprisingly easy to get used to," he said. "They have new faces, but they still have a way of speaking and have the same body language."

Another study author , Dr. Daniel S. Alam, is the head of the section of facial aesthetic and reconstructive surgery in the Head and Neck Institute at the Cleveland Clinic in Ohio. He said the new article is important because it is the first time face transplants have been reported as a series of cases.

Alam was involved with Nash's surgery, and also performed the first U.S. face transplant -- on gunshot victim Connie Culp, in December of 2008.

"Five years ago, we didn't know if this could be done. Full face transplants can be done technically, they can be done safely and patients can get a lasting benefit," he said. The new study's publication marks "the end of the first chapter and now we need Chapter Two, to see who is the right patient and work toward making the surgery better and better," Alam said.

That remains a work in progress. "Surgeons have been taking gall bladders out for years [for example], but we are extremely early in our learning curve for face transplants," he said.

Another expert agreed.

"Face transplants are here to stay," said Dr. Edwin F. Williams III, a facial plastic surgeon in Albany, N.Y., and vice president of public affairs at the American Academy of Facial Plastic and Reconstructive Surgery.

However, he added, "we really need to move forward carefully and they won't be something that happen in every small town and city."

More information

For more information on some of the issues surrounding face transplants, visit the American Academy of Facial Plastic and Rec...tructive Surgery.