Is world's first human head transplant 'imminent'?
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Posted 14 February 2018 - 01:15 AM
Is world's first human head transplant 'imminent'?
An Italian doctor announced Friday that he will soon perform the world’s first human head transplant in China because medical communities in the United States and Europe would not permit the controversial procedure.
"The Americans did not understand," Sergio Canavero told a news conference in Vienna.
Canavero said the Chinese government and Xiaoping Ren, a Chinese doctor partnering with him on the procedure, would confirm the surgery's date "within days" to signal its goal of becoming a world leader in all fields, including medicine.
"Chinese President Xi Jinping wants to restore China to greatness. He wants to make it the sole superpower in the world. I believe he is doing it," Canavero said.
In a phone interview with USA TODAY, Canavero decried the unwillingness of the U.S. or Europe to host the surgery.
"No American medical institute or center would pursue this, and there is no will by the U.S. government to support it," he said
Canavero would not divulge the identity of the Chinese donor or recipient. The donor will be the healthy body of a brain-dead patient matched for build with a recipient's disease-free head.
Canavero estimates the procedure will cost up to $100 million and involve several dozen surgeons and other specialists.
He will simultaneously sever the spinal cords of the donor and recipient with a diamond blade. To protect the recipient's brain from immediate death before it is attached to the body, it will be cooled to a state of deep hypothermia.
The recipient and donor will be in a sitting position to facilitate what's expected to be more than about 24 hours of laborious work to separate and then reconnect vertebral bones, jugular veins, the trachea, esophagus and other neck structures.
Machines will help the recipient breathe, pumping blood through the body. The patient will be kept in a drug-induced coma for an unspecified recovery time
Michael Sarr, a former surgeon at the Mayo Clinic in Rochester, Minn., and the editor of the journal Surgery, said Canavero's procedure is radical.
Doctors "have always been taught that when you cut a nerve, the 'downstream side,' the part that takes a signal and conducts it to else, dies," he said. "The 'upstream side,' the part that generates the signal, dies back a little — a millimeter or two — and eventually regrows. As long as that 'downstream' channel is still there, it can regrow through that channel, but only for a length of about a foot."
This is why, he said, if you amputate your wrist and then re-implant it and line the nerves up well, you can recover function in your hand. But if your arm gets amputated at the shoulder, it won't be re-implanted because it will never lead to a functional hand.
"What Canavero will do differently is bathe the ends of the nerves in a solution that stabilizes the membranes and put them back together," Sarr said. "The nerves will be fused, but won't regrow. And he will do this not in the peripheral nerves such as you find in the arm, but in the spinal cord, where there's multiple types of nerve channels."
There has been some success using Canavero's proposed technique on mice and dogs. In one example, a dog walked after six weeks, albeit with an awkward gait. "Based on the classic thinking about how nerves regenerate it was unbelievable," Sarr said.
Canavero said his team has "rehearsed" his technique with human cadavers in China, but there are otherwise no known human trials. He said the 18-hour operation on two corpses showed it was possible to reconnect the spinal cord and blood vessels. Before the full transplant takes place, two brain-dead patients will undergo the surgery.
Most medical experts say it's a long shot, but even if the operation works the biggest obstacle may not be the science itself, but whether it should happen at all.
"There are too many risks at this point to go ahead with it," said Assya Pascalev, a biomedical ethicist at Howard University in Washington, D.C. "We don't have enough data with animal models, sufficient published and peer-reviewed results, and particularly data about morbidity and mortality on the animals that have had the procedure."
Pascalev said that any groundbreaking procedure is certain to face objections and skepticism, and requires a leap of faith.
"The first heart transplant, hand transplant, facial transplant: all were met with serious reservations," Pascalev said. "There are also regulatory concerns. China does not have the same ethical standards and requirements that the United States and Europe have."
She added that there were major unanswered questions about the recipient if the surgery succeeds, such as whether he or she would have legal rights to children produced by the new body. "It's not just about a head adjusting to a new body. We might be dealing with a whole new person."
Canavero dismissed these concerns. "Western bioethicists needed to stop patronizing the world," he said. He added that China's receptiveness to hosting the surgery reflected its determination to replace the U.S. as the world leader in all fields.
"Who sent America to the Moon? It was Wernher von Braun," he said, referring to the German immigrant who was an early rocket developer and space-exploration advocate for the U.S.
James Giordano, a professor of medicine and neurosciences at Georgetown University Medical Center in Washington, agreed with Pascalev that not enough rigorous study has been done to support a procedure with so many risks.
He said patients might be better served if Canavero focused on spinal reconstruction, not transplants. Yet he also gave him some credit for his pioneering work.
"He's run the ethical flag up the poles and said, 'Look, I'm not an ethicist, I'm a neurologist and this may be an avant-garde technique, I recognize there is a high possibility for failure, but this is the only way we can push the envelope and probe the cutting edge to determine what works, what doesn't and why.'"
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