Canavero hopes to assemble a team to explore the radical surgery in a project he is due to launch at a meeting for neurological surgeons in Maryland this June.
He has claimed for years that medical science has advanced to the point that a full body transplant is plausible, but the proposal has caused raised eyebrows, horror and profound disbelief in other surgeons.
The Italian doctor, who recently published a broad outline of how the surgery could be performed, told New Scientist magazine that he wanted to use body transplants to prolong the lives of people affected by terminal diseases.
“If society doesn’t want it, I won’t do it. But if people don’t want it, in the US or Europe, that doesn’t mean it won’t be done somewhere else,” he said. “I’m trying to go about this the right way, but before going to the moon, you want to make sure people will follow you.”
Putting aside the considerable technical issues involved in removing a living person’s head, grafting it to a dead body, reviving the reconstructed person and retraining their brain to use thousands of unfamiliar spinal cord nerves, the ethics are problematic.
The history of transplantation is full of cases where people hated their new appendages and had them removed. The psychological burden of emerging from anaesthetic with an entirely new body is firmly in uncharted territory. Another hitch is that medical ethics boards would almost certainly not approve experiments in primates to test whether the procedure works.
But Canavero wants to provoke a debate around these issues. “The real stumbling block is the ethics,” he told New Scientist. “Should this surgery be done at all? There are obviously going to be many people who disagree with it.”
The idea of body transplants – or head transplants, depending on the perspective – has been tried before. In 1970, Robert White led a team at Case Western Reserve University in Cleveland, US, that tried to transplant the head of one monkey on to the body of another. The surgeons stopped short of a full spinal cord transfer, so the monkey could not move its body.
A lull in attempted body transplants followed White’s experiments, but last year researchers at Harbin Medical University in China made some headway with mice. They hope to perfect a procedure they claim “will become a milestone of medical history and potentially could save millions of people”.
Despite Canavero’s enthusiasm, many surgeons and neuroscientists believe massive technical hurdles push full body transplants into the distant future. The starkest problem is that no one knows how to reconnect spinal nerves and make them work again. Were that possible, people paralysed by spinal injuries could have surgery to make them walk again.
“There is no evidence that the connectivity of cord and brain would lead to useful sentient or motor function following head transplantation,” Richard Borgens, director of the Center for Paralysis Research at Purdue University in Indiana, US, told New Scientist.
According to the procedure Canavero outlined this month, doctors would first cool the patient’s head and the donor’s body so their cells do not die during the operation. The neck is then cut through, the blood vessels linked up with thin tubes, and the spinal cord cut with an exceptionally sharp knife to minimise nerve damage. The recipient’s head is then moved on to the donor’s body.
The next stage is trickier. Canavero believes that the spinal cord nerves that would allow the recipient’s brain to talk to the donor’s body can be fused together using a substance called polyethylene glycol. To stop the patient moving, they must be kept in a coma for weeks. When they come round, Canavero believes they would be able to speak and feel their face, though he predicts they would need a year of physiotherapy before they could move the body.
“This is such an overwhelming project, the possibility of it happening is very unlikely,” Harry Goldsmith, professor of neurological surgery at the University of California, Davis, told the magazine.
source: theguardian.com by Ian Sample