The controversial Italian surgeon on the impossible quest to transplant a human head recently claimed to have “succeeded” in this task on two cadavers.
Sergio Canavero is an Italian neuroscientist and surgeon who thinks head transplants are not the stuff of science fiction anymore. Together with collaborators in China, Canavero claimed to have successfully transplanted the head of a cadaver to the body of a second cadaver. During the 18-hour procedure, Canavero and his main collaborator, Xiaoping Ren of Harbin Medical University, China, say they joined the critical nerves and blood vessels, spine and spinal cord of two bodies. Based on the “success” of this procedure, Canavero believes live human head transplants would be “imminent.”
This experiment may be Canavero’s boldest yet, but it’s certainly not his first. In recent years, he made headlines for his claims that head transplants worked in mice, rats, and a dog. He also claimed to have successfully transplanted a head on a live monkey in 2016.
However, scrutiny on the evidence has revealed much doubt and little confidence. For example, the small animal experiments were done in five rats, four of which were killed in a lab flood, thus delivering no results. The experiment in the remaining rat and one dog did show movement after the purported surgery, but critics remain skeptical that the spinal cord was actually severed. As for the monkey, the animal did not survive beyond 20 hours post-procedure, prompting many to question Canavero’s definition of “success.”
It’s “the continuation of a despicable fraud," said Arthur Caplan, a bioethics professor at New York University's Langone Medical Center. Caplan is referring to Canavero’s seemingly cavalier and reckless trail of “successes.”
But what does a head transplant procedure entail according to Canavero?
First, Canavero says the patient’s head has to be essentially frozen to prevent brain damage while the procedure takes place. Then, the team would begin to detach the head from the body – taking great care from big veins and arteries to small tubes and blood vessels. Cutting the biggest cord of all – the spinal cord – will be the most precarious task. Canavero says this will be done with a special knife made from diamonds. Yes, a diamond knife to sever the spinal cord from a frozen head – let that sink in for a minute.
After removing the head from the body, the team essentially would work in reverse to attach the patient’s spinal cord, veins, arteries, and tubes to the donor body. The operation starts to sound even more suspicious, as Canavero plans to help reattach the tissues with polyethylene glycol (PEG) – a chemical that would act as a glue to bond the tissues together. Canavero has yet to detail how this will work with a frozen head.
There are endless other unresolved challenges that Canavero has yet to address.
Caplan points out the problem of transplant rejection as one such hurdle. "We have a face transplant program here [at NYU] — it is very difficult to just transplant the face. It requires massive doses of immunosuppressant,” said Caplan. "The head would be an even bigger problem, requiring even bigger doses. It would probably kill you in a few years from rejection or infection."
And then there’s the question of if and how a transplanted head could actually regain consciousness, which is arguably the most important aspect of being human. "It's not like putting a light bulb into a new socket," Caplan said. "If you move the head and the brain, you are putting it into a new chemical environment with new neurological input. I think it would drive the person crazy before they died."
Importantly, because the details of this cadaver head transplant have not been published in peer-reviewed journals, critics continue to question the scientific validity and ethical integrity of Canavero’s techniques.
Despite the pushback, Canavero says he already has a list of people who are willing to give it a try. To these people, some of whom are paralyzed or otherwise physically disabled, a head transplant would be like science fiction to their rescue. But everyone should be extremely skeptical, as a false move could result in a fate “considerably worse than death,” wrote one scientist grimly.