Surgeons in the US have performed what they claim is the most extensive full-face transplant yet performed, repairing the face of a 37-year-old man who lost his lips and nose 15 years ago in a gunshot accident. The graft could reveal better ways to stop a patient's body rejecting donated tissue.
Richard Lee Norris of Hillsville, Virginia, received almost the entire face from a donor. The donated tissue ran from the scalp and included all elements of the face down to ? but not including ? the collar bones. It also contained the bones of both jaws, teeth devoid of any fillings, and the third of the tongue extending to its tip.
"All these segments have been transplanted in the past and the other groups of surgeons have led the way for us, but no one has included all these components," says lead surgeon Eduardo Rodriguez of the University of Maryland Medical Center in Baltimore, where the 36-hour operation took place on 19 and 20 March.
The other major innovation is the inclusion in the jaws of the donor's bone marrow, still fed by blood vessels, which could mean that Norris will need less immunosuppressing therapy to stop his body rejecting the foreign grafts.
Chimeric harmony
Experiments by Rodriguez's team in animals ? published last year in the American Journal of Transplantation (DOI: 10.1111/j.1600-6143.2011.03551.x) ? demonstrated that transplants suffer less rejection by the immune system if they include "vascularised" bone marrow fed by blood vessels, than if there is no bone at all in the transplant.
"We have confirmation of that in vascularised bone transplants," says Rodriguez. "So vascularised bone marrow might be better than infusions of bone marrow stem cells to create a situation where the donor and recipient cells can live in chimeric harmony."
The hope is that the same effect will be seen in Norris. "The good thing is the large vascularised bone marrow content, which has potential to assist in the long-term survival of the graft," says Rodriguez.
Increasing challenges
The breakthrough continues a trend of steadily larger facial grafts since the first, in 2005, on Isabelle Dinoire in France. That graft covered only the lower part of her face. A Spanish team in 2010 announced what they claimed was the first full-face transplant, but Rodriguez says that it didn't include the tongue.
"The reason surgeons are transplanting more and more tissue is because increasingly difficult patients with more and more deficits are being considered for transplant," says Maria Siemionow of the Cleveland Clinic Foundation in Ohio, the surgeon whose team carried out the first US face transplant in 2008.
But Siemionow says it doesn't necessarily mean that "more is better", as there are risks in removing perfectly functional pre-existing tissue to replace it with donated tissue. "And you have potential problems with bail-out or rescue procedures if the graft goes wrong."
For example, Siemionow's transplant patient, Connie Culp, had functional upper eyelids, so it would have been risky to sacrifice those to replace them with donated tissue.
Abilities regained
According to Siemionow, the most important advance in face transplants over the previous practice of using skin grafts is that the transplant includes functional elements such as nerves and muscles which integrate with the patient's own to give them abilities they may have lost through an accident.
Norris, for example, couldn't chew food or speak properly, but has the promise to do so now that he has new jaws and teeth, and a complete tongue which should enable him to pronounce words properly. Meanwhile, Culp can now breathe independently, smile, eat solid food, smell, and sense full feelings in her face, none of which she could do before.
Siemionow says the biggest unsolved challenge remains the need for lifelong immunosuppression. "That's a very important goal for the future," she says.
She adds that it remains to be seen whether Rodriguez's claims for vascularised bone marrow improving acceptance will prove correct.
Another important development is coordination between transplant providers. A US and international registry of potential recipients is to be launched later this year.
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article
Subscribe now to comment.
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
st bonaventure ncaa tournament 2012 peyton manning 49ers andy pettitte tyler clementi kevin kolb sarah shahi
কোন মন্তব্য নেই:
একটি মন্তব্য পোস্ট করুন