BY: DANIEL KORN
There’s a Philosophy 101 thought experiment called Theseus’s Ship. The paradox goes like this: say I have a wooden sailboat, and I want to replace every plank of wood on the thing one-by-one. The planks are made of the same wood and have the same specifications of the original ship. At what point is the ship, despite looking and functioning in the same way, no longer my original ship? The paradox is meant to question identity, both of objects and selves.
Italian neuroscientist Sergio Canavero is looking to take the question out of the theoretical realm and into the practical one, bringing the harrowing question to our own bodies—if I take my head and put it on a different body, am I still me?
Canavero believes that he can have the first head transplant—where people with extreme muscle and nerve damage or untreatable cancer in their organs have their heads transplanted onto a different body—complete by 2017. This sort of esoteric treatment comes with a lot of complications but Canavero believes that medical technology is at a point where these issues can be effectively dealt with. Most of his peers believe the 2017 goal is unlikely at best, and are pretty sure Canavero won’t ever be able to do it; he remains optimistic.
In 1954, a dog’s head and forelegs were transplanted onto a larger dog’s body by surgeon Vladimir Demikhov
It wouldn’t be the first time someone’s tried to transplant a head onto a new body. In 1954, a dog’s head and forelegs were transplanted onto a larger dog’s body by surgeon Vladimir Demikhov—the dog(s) only lived between two and six days. In 1970, a team led by neurosurgeon Robert White transplanted a head of one monkey onto the body of another. The monkey was able to breathe—with artificial assistance—as well as ostensibly see, hear, and smell, though it couldn’t move the body due to the team opting not to connect the spinal cords. The body’s immune system ended up rejecting the transplant after nine days. More recently, neuroscientist Xiaoping Ren and his team were able to exchange the heads of 18 mice, though they were paralyzed from the neck down and only survived for about three hours.
So the prospects aren’t great, and the likelihood of them being vastly improved—in humans no less, which is a very different game than animals—in the next two years is slim. Canavero seems like a bit of a crack in interviews, not particularly concerned with patients’ safety nor the ethical dilemmas with the procedure, and most of his peers are either skeptical or downright dismissive of his claims.
Robert J White’s Transplanted Monkey Head lived for 9 days with an artificial breathing mechanism.
Regardless, his ideas have enough merit that he’s being featured as the keynote speaker at the annual meeting of the American Academy of Neurological and Orthopaedic Surgeons in June—this will allow him to gauge how much interest there is in the head transplant project, and if nothing else, his methods for spinal fusion could be a boon to paraplegics and quadriplegics.
The actual proposed transplant procedure goes like this—and be warned that this is going to deal with some gnarly stuff, so you might want to skip down a couple paragraphs if you’re squeamish.
First, the head and donor body are placed in suspended animation in order to extend the time that cells are able to survive without oxygen. The tissue around the neck is dissected, and the spinal cords of the head and body are cut cleanly, so as not to prevent nerve cells from being able to regenerate properly. The neurons—which are likened to spaghetti by Canavero—are then fused with a substance called polyethylene glycol.
Canavero believes that he can have the first head transplant complete by 2017.
The patient is then kept in a coma for 2-4 weeks, at which point the axons will start to connect with each other and the patient can be revived. The splice will be bathed with mild electrical current both during and after the coma, theoretically keeping the muscle cells operational, and when combined with physical therapy, the patient should be able to walk in about a year.
There are problems with just about every aspect of the surgery. Creating a clean cut in the spine is extremely difficult, and the “special, ultra-thin blade” required to do so doesn’t seem to have been developed yet. Inducing a coma is usually a last-resort tactic, and carries risks of blood clots, infection, and brain damage. Then there’s issue of immune system rejection, though Canavero believes that since we can already use the drugs to manage the transplant of hearts and lungs, a head shouldn’t be so difficult. Most importantly, cells in the central nervous system—the brain and spine—do not naturally regenerate, which makes regaining motor control an impossibility. Spinal cells could potentially be regrown with stem cell therapy, but it’s only been tested in rats, and according to researcher Mark Tuszynski, is years away from being used in clinical trials.
So it seems unlikely to succeed, not to mention kind of gross and invasive. Still, apparently many people have signed up to be guinea pigs for the mad doctor, sketchy science be damned.
Personally, I’d rather just wait until the science gets to a point where I can get a second, identical-yet-more-confrontational head grafted on beside my original one, Zaphod Beeblebrox style.
Sources: snstatic.fi, weirdworldwonders.com, horribl.com, newsradioklbj.com, twimg.com
