No, there hasn’t been a human 'head transplant', and there may never be

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This article titled “No, there hasn’t been a human ‘head transplant’, and there may never be” was written by Dean Burnett, for theguardian.com on Friday 17th November 2017 14.20 UTC

In February 2015, Sergio Canavero appeared in this very publication claiming a live human head will be successfully transplanted onto a donor human body within two years. He’s popped up in the media a lot since then, but two years and nine months later, how are things looking?

Well, he’s only gone and done it! As we can see in this Telegraph story from today, the world’s first human head transplant has been successfully carried out. Guess all those more timid neurobods who said it couldn’t be done (myself included) are feeling pretty foolish right now, eh?

Well, not quite. Because if you look past the triumphant and shocking headlines, the truth of the matter becomes very clear, very quickly. In the interest of full disclosure, I do not know Dr Sergio Canavero, he’s done nothing to me directly that I’m aware of. However, I’m now seriously doubting his motivations. I’ve discussed my reasons for this elsewhere before now, but here they are again in one place for ease of reading.

Even the fictional Dr Frankenstein had a better success rate. Photograph: Hulton Archive/Getty Images

These “successful” procedures are anything but

Many of Canavero’s previous appearances in the media have been accompanied by claims of successful head transplant procedures. But, how are we defining “successful” here? Canavero’s definition seems to be extremely “generous” at best.

For instance, he recently claimed to have “successfully” performed a head transplant on a monkey. But did he? While the monkey head did apparently survive the procedure, it never regained consciousness, it was only kept alive for 20 hours for “ethical reasons” and there was no attempt made at connecting the spinal cord, so even if the monkey had survived long-term it would have been paralysed for life. So, it was a successful procedure, if you consider paralysis, lack of consciousness and a lifespan of less than a day as indicators of “success”.

There was also his “successful” rat head transplant, which involved grafting a severed rat head onto a different rat, a living one that still had its head. Exactly how this counts as a “transplant” is anyone’s guess. It’s adding a (functionally useless) appendage onto an otherwise healthy subject.

And this recent successful human head transplant? It was on corpses! Call me a perfectionist if you must, but I genuinely think that any surgical procedure where the patients or subjects die before it even starts is really stretching the definition of “success” to breaking point. Maybe the procedure did make a good show of “attaching” the nerves and blood vessels on the broad scale, but, so what? That’s just the start of what’s required for a working bodily system. There’s still a way to go. You can weld two halves of different cars together and call it a success if you like, but if the moment you turn the key in the ignition the whole thing explodes, most would be hard pressed to back you up on your brilliance.

Perhaps the techniques used to preserve the heads and attach them have some scientific value, but it’s still a far cry from the idea of someone wandering around with a fully functional body that isn’t the one they were born with. Canavero seems to have a habit of claiming barnstorming triumph based on negligible achievements, or even after making things much worse. He seems to be the neurosurgical equivalent of the UK Brexit negotiating team.

You’d expect copious details when it comes to performing a successful head transplant. Thus far, they’re strangely absent. Photograph: Alamy

The crucial details are strangely overlooked

The human body is not modular. You can’t swap bits around like you would Lego blocks, take a brick from castle and put it onto a pirate ship and have it work fine. There are copious obstacles to contend with when linking a head to body, even when they’re the same person’s. Doctors have, in recent years, “reattached” a severely damaged spinal cord in a young child, but the key-word is “damaged”, not “completely severed”; there’s enough connection still to work with, to repair and reinforce. And this is with a young child, with a still-developing nervous system better able to compensate. Even taking all this into account, and the advanced state of modern medicine, the successful procedure was considered borderline miraculous.

So, to attach a completely severed spinal cord, a fully developed adult one, onto a different one, one that’s maybe been dead for days? That’s, what, at least four further miracles required? And that’s not to take into account immune rejection, the fact that we don’t really know how to “fix” damaged nerves yet (let alone connect two unfamiliar halves) and the issue that everyone’s brain develops in tune with their body. The latter point means the “interface” between the two is relatively unique. You put the head of musician on the body of a builder, it may well prove to be like trying to play an Xbox game on a PlayStation. Except, infinitely more traumatic.

We don’t know for certain of course, because nobody has ever tried it. Canavero seems convinced he can do it, but thus far he’s offered no feasible explanation or science for his claims to be able to overcome these hurdles, beyond some token stuff about preserving tissues and ensuring blood supply during procedures. That’s a bit like someone claiming they can build a working fusion reactor and, when asked how, explains how they’re going to plumb in the toilets for the technicians. Arguably a useful step, but clearly not the main issue here.

TED Talks. Slick, inspiring, interesting, not exactly peer-reviewed. Photograph: Alamy Stock Photo

Hype before substance

I’ve said this before, even in a Wired article about Canavero’s previous claims, to the extent where I am considering trademarking it as “Burnett’s law”. Simply put; if someone’s making grand scientific claims but hasn’t provided robust evidence for them, yet they have done a TED talk, alarm bells should be ringing.

I don’t know what Canavero’s confidence is based on. Nobody seems to. He hasn’t published anything that would warrant it thus far. Note his recent “successful” human head transplant claims, which you can read about in the Telegraph before he’s published the actual results, as stated in the article.

Why do that? Why tell the newspapers before you tell your peers? If your procedure is rigorous and reliable enough, the data should reflect that. When scientists, particularly self-styled “mavericks”, court publicity but desperately avoid scrutiny, that’s never an encouraging sign.

Going by the Telegraph article, Canavero claims that the next step will be to attempt a transplant with someone in a vegetative state or similar. He also claims to have plenty of volunteers for this. Exactly how coma patients actively volunteered for this radical procedure is anyone’s guess.

There’s no mention yet of attempting it in a conscious person, despite there being actual volunteers for that. I strongly suspect there never will be. Trying it with a conscious, thinking person means it absolutely has to be 100% effective for them to remain in this state after the transplant is done. This would mean finding workable solutions to all the considerable obstacles presented by the very concept of a head transplant.

If I’m wrong about this then I’ll gladly take back everything and apologise, but nothing Canavero has said or done thus far leads me to think he has any idea about how to do this.

Dean Burnett is fully aware that the procedure should logically be called a “body transplant” but that’s not how it’s usually described, so has used the more common terms. His book The Idiot Brain is available now, in the UK and US and elsewhere.

 

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