Why left hand works first in double transplant, by study
Fresh researchers have found that when the two hands are transplanted, the left hand works first, even as there are fears that the world's first simultaneous partial-face and double-hand transplant may raise fresh ethical debates.By Chukwuma Muanya with Agency report.
A TEAM of researchers in France reported on Tuesday that when patients had both hands transplanted, their brains re-established connections much more quickly with the left hand than the right.
The sample was small, just two patients, but both had been right-handed before losing their hands, and both followed a pattern of reconnection with their brain that was quicker for the left hand.
The study, led by Angela Sirigu of the Centre for Cognitive Neuroscience at the University of Lyon, France, is reported in Tuesday's edition of Proceedings of the National Academy of Science.
The research shows that even years after the loss of hands the brain can reorganise and rewire itself to recognise and connect to a replacement.
Also, a leading French surgeon says he has now effectively carried out a full face transplant after two operations in the same number of weeks.
Prof. Laurent Lantieri, who has performed three of the world's six partial face transplants, said every feature had now been transferred.
In a lengthy operation at the weekend, a team in Paris transplanted the entire upper part of a man's face. Approval for a full-face transplant was given in the United Kingdom nearly four years ago.
Prof. Peter Butler of London's Royal Free hopes to carry out a definitive procedure including the throat area and all of the scalp within the next 12 months.
These two separate discoveries come just days after French physicians, in a 30-hour operation, performed the world's first simultaneous partial-face and double-hand transplant. Paris' Public Hospital authority described the recipient as a 30-year-old burn victim who was injured in a 2004 accident.
There are fears that the feat may raise fresh ethical debate. In 2005, an ethics debate broke out over the world's first partial face transplant with one surgeon challenging the decision to operate, while others suggested a bit of jealousy might be at play.
At the same time, several doctors raised concerns about the psychological health of the French woman who received a transplanted nose, lips and chin. She had been brutally mauled by a dog, and her identity remains unknown.
Sirigu's team used magnetic imaging to study the brains of people who had lost both hands and to see how the motor region that controls movement responded after new hands were transplanted.
The first case involved LB, a 20-year-old man injured in 2000, who received the transplants in 2003 after having used artificial hand devices in the meantime.
He was checked periodically and the researchers found his brain had re-established nerve connections to control the left hand by 10 months, while it took 26 months to complete the rewiring needed for the right hand.
"Interestingly, despite that LB was right-handed, and that after his amputation he used his prosthetic device mostly with his right hand, hand preference shifted from right to left after he had the graft," the researchers reported.
The second patient studied, CD, was a 46-year-old man who lost both hands in 1996 and received a dual hand transplant in 2000. He was tested by the researchers in 2004, 51 months after the transplants. Strong connections in the brain were observed for the left hand, but not yet the right.
The researchers said more study is needed to determine why the brain reconnected more efficiently to the left hand in these patients. Possibilities include a basically better connection to the left hand, factors in the way that the brain reorganises itself during the process of the loss of a hand and its later replacement, or perhaps some pre-existing difference in brain organisation.
In general, experiments have shown that the right side of the brain controls the left side of the body and many researchers believe it also dominates in such areas as spatial abilities, face recognition, visual imagery and music. The left side of the brain controls the right side of the body and is thought to dominate in language, math and logic. However, many traits are shared by both sides, and if one side is damaged the other can take over many of its functions.
The research was supported by the United States National Science Foundation, the French National Centre for Scientific Research, the International Brain Organisation and other organisations in Brazil, France and Canada.
The first partial face transplant was carried out by doctors in Amiens in 2005 on Isabelle Dinoire, a 38-year-old woman who had been mauled by her dog. She received a new nose, chin and lips.
Despite concerns that her body might reject the donor's tissue, she is said to have adapted extremely well to her new face - not just physically but also psychologically.
Since then partial face transplants have also been carried out in China and the United States. In the Chinese case, the patient - who had been mauled by a bear - has since died.
Last year in Cleveland doctors claimed the most extensive face transplant yet, replacing 80 per cent of a woman's face with that of a dead donor's.
Three other face transplants have also been carried out in France. At the end of last month, surgeons at the Henri Mondor Hospital in Paris spent 15 hours on the face of a man whose original features were blown off in a shooting accident.
But in this latest operation this weekend on a 30-year-old man severely burned in a 2004 accident, doctors claimed to have broken new ground.
As well as transplanting hands at the same time, the upper half of the man's face, including the scalp, forehead, nose, ears and upper and lower eyelids, were transferred - in what is understood to be a first.
"Now that we have realised this part, there's not really much point talking about the full face transplant anymore. Technically it is done," Lantieri said. "You transplant according to the patient's need."
His team will carry out two more such procedures in the next few months as part of a trial, which saw five operations, approved. Once the results are reviewed, he says he hopes to see the procedure more widely available in specialist centres within the next few years.
In the UK, Professor Butler says he has been approached by 34 patients who have expressed interest in a transplant but rigorous selection procedures had slowed the process down.
"We have been working through the psychological issues of transplantation," he told the BBC. "Would this person have a significant difficulty with this type of change of appearance? The interesting thing with people with facial injury is that you have an idea of how they have already coped with facial change."
But he also stressed that contrary to popular perceptions of people inheriting the faces of the dead, "you get is a hybrid, something between the donor and the recipient. What you get is more like the recipient than the donor".
Prof. Iain Hutchinson, an oral-facial surgeon at Barts and the London Hospital and head of the charity Saving Faces, said the debate about the first full face transplant had long been "academic".
"The race is already won. The first face transplant was done by the French. The ethical boundaries have been crossed," he said.
"But we have to remember that there are significant hazards attached to this - the side effects of the immunosuppressant drugs patients must take for the rest of their lives for instance. The issue here remains that this is a huge operation - but not a life-saving one."