For the past few years he's been working in China where there's less squeamishness in the government about such experiments, and although he claims that the procedure works, he's been unable to present verification of his claims.
Now comes word that Canavero is working on a much more complicated surgery - brain transplants (BT):
In 2017,... Canavero and Chinese colleague Xiaoping Ren [reported] a head transplant rehearsal with human cadavers. A live volunteer subject, a Russian man with a genetic degenerative muscle atrophying disease, pulled out of the planned procedure in 2019.But an HT is much simpler than a BT. Why undertake the more difficult procedure?
Also in that year, ... Canavero and Ren ... reported a successful spinal cord repair in animals.
Canavero told Motherboard he’s not free “to talk about the HT project that unfolded in China, other than saying it works.”
In his latest paper [see here] —which is co-edited by himself and Ren—Canavero describes how to theoretically remove one person’s brain to place it into the skull of either a clone or a donated and brain-dead “immunoconditioned” body.
In addition to describing a “robotic scoop with retractable tines” that would pluck the brains from their skulls, Canavero also provides possible solutions to several outstanding questions surrounding brain transplants, including nerve and vascular reconnection methods.
“The unavailability of technologies that can successfully rejuvenate an aged body suggests that it is time to explore other options,” the paper notes. “Contrary to common lore, a full BT is achievable, at least theoretically.
Of course, further extensive cadaveric rehearsals will be necessary, followed by tests in brain-dead organ donors (as e.g., done recently in kidney xenotransplants). New surgical tools will have to be developed. With appropriate funding, a long-held dream may finally come true.”
Canavero makes the point that putting an aging head with sagging skin, fading eyesight, hearing, teeth, etc. on a younger body doesn't allow the patient to enjoy the full benefit of the more youthful body. Transplanting the brain into the complete body would be more desirable:
The ultimate goal of such a procedure would be to extend the number of years a person could enjoy living in a “pristine body,” Canavero writes in his paper.Some of my students have objected to such a procedure on ethical grounds. In their opinion, transplanting a head or brain is more morally problematic than transplanting a heart or liver.
....Problematic or not, there is big interest in extending human life, and an entire branch of science and pseudoscience dedicated to “transhumanism” and life extension, including among Silicon Valley elite. These methods include everything from taking specific substances to “young blood” transfusions, cryogenics, and attempts to recreate humans as immortal AI.
Whatever the validity of the ethical objections may be, one question that a BT raises is who, exactly, is the recipient after he or she has received the new brain?
Is the recipient now the person whose brain he/she has received or is the recipient the same person with a new brain, just as patients who receive a new heart are still the same person they were before they received the heart?
Or is the recipient a new person altogether?
Where does "personhood" reside, anyway? In the brain or in the body? Or both?
If you believe individuals have a mind and/or a soul does the BT recipient now have a new mind or soul? If the individual whose brain has been donated had committed a crime or owed a debt is the recipient now liable for those?
If the recipient was married are they still married to the same spouse after the procedure?
Canavero has yet to show that what he proposes can be actually be done, but assuming that it can, it raises perplexing philosophical questions in the matter of personal identity.