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Human Head Transplant Possible By 2017, Scientist Claims
The world’s first human head transplant could take place as soon as 2017 if controversial plans by Italian neuroscientist Dr. Sergio Canavero come to pass, according to an article posted on the Conversation website. Wheelchair-bound Valery Spiridinov, who has the muscle-wasting Werdnig–Hoffman disease, has volunteered to have his head transplanted onto a healthy body in a day-long operation.
The whole process, Canavero said, is “90%” guaranteed to succeed, although he admitted: “Of course, there is a marginal risk. I cannot deny that."
Other scientists have expressed serious doubts about the procedure and, in particular, about the likelihood that Spiridinov’s brain will still be functional by the time the surgery is complete.
Canavero’s plans also raise philosophical and ethical issues. One of these is whether a living person with Spiridinov’s head and someone else’s body would be the same person as Spiridinov. In interviews, Spiridinov has made it clear that he sees the proposed procedure as a way for him to live on with a new and healthy body.
Stage one of Canavero’s procedure involves cooling the patient and donor’s bodies to prevent the brain cells from dying during the operation. Next, the neck is partially severed, and the major blood vessels from one body are linked to the other with tubes.
In stage two, the spinal cord is cut with an extremely fine blade to minimize damage. The donor head is then removed and placed on the recipient’s neck, and the spinal cord is fused back together with the growth-stimulating chemical polyethylene glycol, a compound used in both medicine and industrial manufacturing.
Stage three involves knitting together the survivor’s blood vessels and nerves. The body is then kept in a coma for several weeks to prevent movement and to allow time for the ends of the spinal cords to heal together.
So, will it work? Not likely, according to an article published in Popular Science. The biggest issue is connecting the spinal cord to the brain so that the head can control its new body. Canavero suggests using polyethylene glycol to join the neurons. This chemical has been shown to heal spinal cord injuries in rats, but it has never been used to connect the spinal cords of two different animals (or people). Moreover, if the site develops scar tissue — which is not uncommon during transplants — it could prevent the neurons from fusing together.
Canavero’s procedure would also require patients to lie in a coma for up to a month while the spinal cords fuse together to ensure that the cords don’t get twisted out of place during movement. That’s also a potential problem, Harry Goldsmith, a professor of neurosurgery at the University of California, Davis, told Popular Science. Medically induced comas are usually a last resort for doctors, as they carry the risk of blood clots, infection, and reduced brain activity.
Finally, the surgery would be extremely difficult. If the brain goes without oxygen for too long, it could die.
In November 2014, Chinese researchers managed to exchange the heads of 18 mice. The transplanted heads had normal brain functioning. They were able to blink and wiggle their whiskers, but they were paralyzed from the neck down. They survived for about 3 hours after they were removed from a ventilator.
Canavero has mentioned trialing his research in countries where scientific and ethical regulations aren’t so strict.
Sources: The Conversation; June 23, 2015; London Telegraph; June 13, 2015; and Popular Science; February 27, 2015.