Are human head transplants on the horizon?

The past few posts I’ve written have been on the brain and neurology. I’m sure that some of the posts have sounded almost like science fiction rather than science:

Some amazing information, and true. And, even though they may sound far-fetched, most of us probably realized that, with current research techniques, they are possible. We will surely build on this research in the future. Whether those future outcomes are great (brain repair using cloned neural tissue) or horrific (motor or mind control) remains to be seen. However, when I read a paper describing this next research proposal – head transplants – I thought it was pure science fantasy.

Injury to neural tissue is difficult to repair. Nerves can be fragile things. We’ve seen people who have had traumatic injuries, or neurologic diseases, of the spinal cord who have been paralyzed. An example of the former is the late Christopher Reeve, who sustained spinal cord damage as the result of a fall. The latter is exemplified by Stephen Hawking, who has Amyotophic Lateral Sclerosis (ALS, Lou Gehrig’s disease). Both were almost completely paralyzed as a result.

Heads via Shutterstock

Heads via Shutterstock

What happens when neurological tissue is damaged? Many things that are far beyond the scope of this article. But, briefly, a few of the mechanisms are: immediate damage to the neurons, that can be deadly to them either immediately or over time, swelling, decreased blood supply, bleeding into the damaged tissue, release of neurotransmitters, damage from free radicals and scarring. All of those make repair very difficult.

Treatment includes stabilizing the area to prevent additional movement, surgery to decompress the area, remove debris and blood from the area and other treatments. Speed is of the essence, some studies show better outcomes when the area is treated quickly after the injury.

Experiments have shown that if the spinal cord is severed surgically (i.e., very precisely and cleanly) it can be reunited and the cells are able to regenerate better, to a degree. Additional research has focused on preventing scarring and enhancing the neurons’ ability to repair themselves.

Some of the early spinal cord work was done in the 1970s and 1980s. But the techniques available didn’t produce very good results in experimental animals. However, there have been some major changes since then.

Reapproximating the cut areas of the cord precisely, using microsurgical and other techniques, and the use of medications and chemicals, have started to produce impressive results. So much so that a neurosurgeon did a paper on the possibility of human head transplantation.

Sounds like science fiction. But so were kidney transplants until the 1950s. So was most heart surgery till the heart-lung bypass pump was developed.

Animal head transplants have been done for over 40+ years

Many people do not realize that animal head transplants have been done for over 40 years. Sometimes the donor head is connected to the recipient’s body. Other times the recipient’s head is removed and the donor head implanted. The first produces a two-headed animal.  Reportedly, a number of two-headed dogs were produced. Both heads could breathe and eat. But the dogs died in less than a month because of rejection issues with the transplanted head.

Similar experiments were done in monkeys, but the monkey’s own head was removed and the donor head attached, producing a one-headed animal. Again, these animals only lived a short time, but the heads did function. One of the transplanted monkey’s heads even tried to bite the researchers.

These experimental animals were sacrificed after a few days. If not, the animals would have probably died from rejection. Remember, though, that much more is now known about tissue compatibility matching, the phenomenon of rejection and snit-rejection drugs, than was available in the 1970s and 1980s.

The author of this article is neurosurgeon Sergio Canavero. He’s written in detail about just how the surgery would need to be carried out, and the details behind preparation of the patients, surgical teams, operating rooms, technology and other factors. The paper has been published in a peer-reviewed journal and is available, online, for free. It’s worth reading, however it is really technical and detailed at times.

I am an MD, but I’m not a neurosurgeon, much less a surgeon. But I think that his article is very well thought out and the planning seems good. We may not ever know if it would work until it is attempted.

Aside from the technical issues, which are many, it raises a number of other interesting and difficult questions.

Is it even ethical to attempt a human head transplant?

The cost of a surgical procedure like this would be millions of dollars (after the construction of special operating rooms, obtaining necessary equipment, training surgeons and staff, etc.). Would it ever be worth is to spend that much money to save one life? If “yes,” who would qualify? How would we prioritize?

Would this lead to black market surgery for those who could afford it to have a chance at quasi-immortality? A black market in “recipient” bodies who are procured because of histocompatibility to the oncoming head transplant?

Does the chimera produced have the identity of the “body,” the identity of the “head,” both, or is it an entirely new person?

Does its new family consist of both of the previous beings’ families? If it has children, are they legally part of the biologic parent (i.e., from his reproductive cells) or the cerebral parent (who directed the procreative act), both, or is it the child of a new person?  (Genetically, they’d be the children of the body-parent, not the head-parent. But what about legally?)

I don’t know the answers. Perhaps they aren’t answerable, no transplant like this has ever been attempted.

What do you think about these issues? Are there even other problems that must be addressed?

Mark Thoma, MD, is a physician who did his residency in internal medicine. Mark has a long history of social activism, and was an early technogeek, and science junkie, after evolving through his nerd phase. Favorite quote: “The most exciting phrase to hear in science... is not 'Eureka!' (I found it!) but 'That's funny.'” - Isaac Asimov

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33 Responses to “Are human head transplants on the horizon?”

  1. Doffing Dardu says:

    You don’t sign up for a new head, you sign up for a new body. Whoever has the head is going to be in control. I think if it’s a lifesaving procedure you’re not going to care what body you get

  2. Doffing Dardu says:

    I realize this has never been attempted, but the questions at the end are kind of asinine.

    Would this lead to black market surgery for those who could afford it
    to have a chance at quasi-immortality?

    Of course there would be a black market surgery, however, not right away because there would have to be extensive training and I read that it would take a team of surgeons to make this possible.

    Does the chimera produced have the identity of the “body,” the identity of the “head,” both, or is it an entirely new person?

    Obviously it’s going to have the identity of the head, how is this even a question?

    Does its new family consist of both of the previous beings’ families?

    Once again why is this question asked, if I donate a kidney to someone I don’t have legal rights

    to the recipient. It’s the exact same thing except someone is donating an entire body rather than one

    (Genetically, they’d be the children of the body-parent, not the
    head-parent. But what about legally?)

    The guy who wrote this article is an MD and he really needs to ask this?

    I don’t know the answers. Perhaps they aren’t answerable, no transplant like this has ever been attempted.

    Obviously you don’t know the answers to these dumb questions or you wouldn’t have asked them.

  3. Ninong says:

    You’re no doubt correct in predicting that our political geniuses would come up with laws based on their religious beliefs rather than science but the more I think about it, the more I come to realize that our brain isn’t any more unique than any other part of our bodies other than that it is the repository of stored experiences.

    It’s basically our DNA that is unique. The brain is simply how we become self-aware and where we keep all our experiences — our memories — as well as the command center that gives orders to the rest of the body.

  4. docsterx says:

    Not necessarily artificial.

    What I meant was that you are assuming that any new laws that might be generated because of this would establish the head as being the “owner” of the body. Our legislative and judicial “giants” may not agree with you. (Most of them skipped genetics, brain death, transplants, rejection, in their evangelical home schools). They may give the body some rights and view the head as a “renter” not “owner.” Or they may shout, “Abomination, worthy of death!” and blugeon the new person to death (unless it has a Bachmann, Trump, Santorum. Perry, Palin head on it).

    As to being programmable, see my article on brain-to-brain interface

    On genetics and personalities, no I’ve never looked into it specifically. But I do know that some identical twins, when separated and raised in different environments ,seem to be much more different than identical who live their whole lives in the same locale: homes, jobs, friends, family, church, etc. I think that it’s a combination of nature and nurture. Genetics, hormones, brain wiring, friends, relatives, role models, education, socialization, etc. A friend is an identical twin. His parents separated when the boys were 4 or 5. He went to Montana to live with his dad. The other twin stayed with mom in fairly rural NY. Montana: likes guns, supports military, loves horses, camping, gay, multiple advanced degrees, atheist/agnostic. NY: hates guns, straight, undergrad degree, afraid of horses, hates camping and outdoors, dislikes military, Catholic. Yet they’re almost impossible to tell apart physically.

  5. Ninong says:

    In other words, you’re predicting an artificial brain to innervate the body so that it could perform all of its normal bodily functions without even the aid of artificial ventilation? I wonder if the artificial brain would also store memories of its new experiences? Interesting.

    Perhaps in the future we will look on the brain as no different than we look on the heart today. We used to consider the heart the repository of our humanity instead of simply a muscle that acts as a recirculating pump. Today we think of the brain as the essence of our humanity but what if it turns out that personality and all the other individual traits that make each of us unique are all determined by genetics? Synthetic genes and programmable gene expression and we could create geniuses, great artists, poets, or psychotic killers.

    P.S. — I have a basis for my comment about genetics and personality. My father was an identical twin and my two best friends are identical twins. Both sets of twins had/have identical personalities. Have you ever looked into that?

  6. docsterx says:

    The body without a brain is only dead now because of our technological limitations. As new laws are formulated the donor body may be seen to have rights that it does not currently.

    “Think of a world with 1,000 Donald Trumps.” I have, we’re safe. He’s too egocentric to permit more than one of himself at a time. And he’d still have the same hair.

  7. Ninong says:

    Poor choice of words on my part. I should have said self-identity or self-awareness. The rest is not really important.

    A body sustained on life support is not truly alive if it doesn’t have a brain. It is simply functioning mechanically by artificial means. If in the future it is possible to extend the life of the brain beyond the physical limits of the rest of the human body and then transfer that brain into a new robotic body, the individual’s self-awareness will now reside in a new home, that’s all. It might be a new and improved home compared to the old one. Sort of like Oscar Pistorius on steroids.

    We need our brains to be alive. Unlike some asteroids, we can’t reproduce by autonomy or fission and unlike polychaetes we can’t reproduce by segmentation. We’re vertebrates with a central nervous system. Without our brain, *we* cease to exist.

  8. JayRandal says:

    Eventually brain transplants of extremely wealthy persons into young bodies. The rich desire to live forever gaining more wealth in perpetuity.

  9. JayRandal says:

    If you put an ugly head on hot young body the person is still a toad.

  10. docsterx says:

    Actually, identity partially resides in the body parts and DNA.
    Fingerprints are unique. The new person’s DNA would vary depending on
    where the cells were collected from. Cells tanen from a mouth swab
    would have the DNA of the head (H). Cells taken from blood, bone
    marrow, ova, sperm and other sites, would have the body’s (B) DNA. Facial photos, views of the ears, dental composition and retina prints would be ID for the H.
    Moles, tattoos, scars would serve as ID for the body. This makes a case
    for a chimera-like organism, a blend of two former independent
    organisms. The way we define identity doesn’t only reside in the brain. A person’s personality,, behaviors, ideas, reside there, but we don’t and can’t identify him solely based on that. We can
    t identify someone just based on how hid brain looks on CT or MRI. Or what it’s brainwave pattern looks like on EEG.

    You’re assuming that the new laws would agree with your stance. There may be a lot of room for discussion there.Yet, there may be a strong case that reproductive tissues and their DNA make the children related to the B solely. The donor and/or his family may not have relinquished rights to future progeny. This could be viewed as analogous to a surrogate mother requiring visitation rights to the child she carried.

    We use brain death as a criterion for death now. The reason being that the body will die if the brain is non-functional. In this case, the B’s brain has died, but the body doesn’t. It’s first sustained on life support and later mated with the head. So the body never died. The body’s head did.

    So Im’ not sure that the H is in control, resolves these issues, if the H is even ruled in control.

    All of these would need to be looked at ethically and legally before making a decision.

  11. Ninong says:

    I wouldn’t call it a head transplant. It’s a full-body transplant. Obviously the identity goes with the brain. It’s not a donor head, it’s a donor body.

  12. okojo says:

    I don’t see head transplants on the horizon. What is medically possible is different than what is an incredibly expensive and long procedure, with little to no medical benefit. What I do see on the horizon, is using stem cells to grow cerebellar cells, that maybe used as transplants for those with Alzheimer disease, senile dementia, or those who had traumatic brain injuries.

    Scientifc possibilities are different than using medical science for more practical purposes. An operation to repair or replace damaged cerebellar cells would be cheaper, much more practical and pass an ethics board than a head transplant that would cost hundred of thousand to a million dollars, (a very long surgery, (24 hours or more) combine with using neurosurgeons, vascular surgeons, orthopedic surgeons, ear, nose throat specialists, along with the need of highly trained nurses in each field. Besides, a good chance of rejection by the human body.

  13. Indigo says:

    I can understand that. But first I want to try out the really hot gay movie star gig at least once. ;-)

  14. Guido says:

    It’s sobering to think of the mistakes which could be made. You’re signed up for a certain head and wind up with somebody else’s head. Say you’re a homely geek type and want Charlton Heston and you wind up Pee Wee Herman instead. Or even worse, maybe you get Sarah Palin’s head, or Idi Amin’s or Ted Nugent’s. On the other hand you could get the Dalai Lama’s head. That might be ok… There are endless opportunities, but the risk of tragedy is too high I’d say.

    Now if they really perfect this thing….

  15. karmanot says:

    Not for me. I want off this planet and never return.

  16. docsterx says:

    There are a number of current US politicians who speak as if their heads are already pickled.

  17. Mike_in_the_Tundra says:

    Wow. I thought I read all of Heinlein’s books when I was a teen, but I don’t recall that one. I guess I’ll have to look for it someplace.

  18. patrickalbino says:

    This topic fueled the plot of Robert A Heinlein’s novel I Will Fear No Evil (1970).

  19. ArthurH says:

    Actually it would be more productive if they put new heads (and brains) on the bodies of John Boehner and Michelle Bachmann. But I’d settle for them having a head swap. Then they could get a show on Comedy Central instead of Congress.

  20. fletcher says:

    The Muppets did it earlier. And the two-headed creature could sing (a parody of “You’re Just in Love”) in which they accused the other head for their maladies.
    First head: “I keep tossing in HIS sleep at night.”
    Second head: “And what’s worse I lost his appetite.”

  21. BeccaM says:

    For some reason, the shortened YouTube links don’t work, but if you copy and paste the one from the address bar, it usually does.

  22. BeccaM says:

    Will do.

  23. heimaey says:

    Thanks, that’s helpful. In Futurama they just kept the heads in jars. Maybe we should just do that instead if we can. Less jerks on the street.

  24. docsterx says:


    The difference between people already paralyzed and the cases described above is that when the cord is damaged in an accident it, may take hours to extract the victim and get him to a medical center that has a neurosurgeon who can do the surgery. By that time, damage has increased: cells are dead/dying, swelling has started, blood loss to some areas, possible bleeding into the area, etc. With the experimental models, the “accident” is performed with surgical precision and immediate efforts to repair it begin. Also, sometimes there is damage to the cord that isn’t immediately apparent to the patient. But after some hours, as damage continues, the patient begins to get symptoms. Then, till he sees a doctor or goes to the ER< the damage may already be done.

    So time is essential and that translates into having rapid transport to a nearby hospital with a neurosurgeon, equipment and staff to do what is necessary. Outcomes are often much worse when treatment is delayed and when it's an accident vs, a surgical procedure.

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  26. microdot says:

    Yeah, I was trying to post the trailer for the Rosie Greer/Ray Milland 1972 trashy blaxploitation film, The Thing With Two Heads, but You Tube is being very uncooperative. Too bad, it was only meant as a bit of humor….

  27. Indigo says:

    I’ll pass on the surgery and wait out my time, then re-incarnate as a really hot gay movie star.

  28. heimaey says:

    I still don’t understand how close we can be when there as so many spinal issues still around that render people paralyzed. When we can put an end to paralyzation and cure the spine, then maybe this will be close to be coming a reality, from my very humble perspective.

  29. microdot says:

    I tried to leave the trailer for The thing with two heads…the 1972 flick starring Rosie Greer and Ray Milland….that would have settled the ethical issues at least….Hey don’t be smokin when I’m eatin!

  30. Moderator3 says:

    Your links are not working.

  31. microdot says:

    been there, done that:

  32. lynchie says:

    I need a head transplant every time I see John Boehner and Michelle Backmann.

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