Surgical pioneer set for the first human head transplant

Nessa Fitzgerald gives an update on the plans to perform the very controversial human head transplant: the surgeon who proposed it and the head donor who is willing to take the risk for a chance of a better life and the advancement of medical science

Credit: stranger


Three years ago, Italian neurosurgeon Sergio Canavero announced that he could perform a human head transplant in a two-part procedure called HEAVEN (head anastomosis venture) and Gemini (the fusion of the spinal cord). Many have dismissed Canavero’s plans, with one bioethicist going so far as to label him a “Looney Tune,” but there are still a few who have hope about his plans, not least of all his first volunteer.

The idea of a head transplant is not new. Organ transplants have been carried out for years, the first successful transplant being that of a kidney in 1954, and since then many other organs and tissues have successfully been transplanted. The head and brain, however, remain un-transplantable. That is not, however, to say that pioneers in the field have not tried. In the 1950s, a pioneer in the field of organ transplantation who had revolutionised heart surgery, Vladimir Demikhov, attempted to carry out head transplants in dogs, leading to two-headed creatures, none of whom lived for more than a month.

His work went on to inspire American neurosurgeon Robert J. White to attempt a head transplant in a rhesus monkey. The monkey remained alive for a few days after the surgery, but because White was unable to fuse the two spinal cords, the monkey was completely paralysed from the neck down, and colleagues would later describe the experiment as barbaric.

More recently, experiments have been carried out which appear to show advances in spinal cord reconstruction, which could potentially lead to the ability to fuse two different spinal cords. Canavero’s experiments appear to show mice moving their limbs after attempts at repairing their severed spinal cords. A dog who had its spinal cord almost completely severed was shown to move just four weeks after attempts at repairing the damage. The researchers claim that their success lies in a chemical called polyethylene glycol, or PEG, which was injected into the gap where the spinal cord was severed.

The study involving mice was, however, very small, with a total of sixteen mice, half of which were part of a control group in which only saline was injected. Of the eight mice treated with PEG, five regained some ability to move, while the other three died, as did all of the mice in the control group. The experiment with the dog did not involve any other individuals, and had no control. There has also been an attempt at a transplant in a monkey, and although the animal survived for around 20 hours after the surgery before being euthanised, no attempt was made at fusing the two spinal cords.  

Canavero plans to carry out the surgery by first cooling the patient’s head to -15C. Both heads are then almost completely severed, leaving the spinal cord intact, and blood vessels are connected by tubes. The spinal cords are then cut using an incredibly sharp, incredibly thin diamond blade, and the process of fusing the two spinal cords begins. The hope is that injecting PEG into the space between the two spinal cords will allow them to join together, letting the patient move the donor’s body. The patient would then be kept in a coma for around a month to allow healing to take place.

It’s difficult to see why anyone would want to subject themselves to such a procedure, on the back of such a small amount of evidence, and yet Canavero has a volunteer. Enter Russian computer scientist, Valery Spiridonov, who suffers from a rare muscle-wasting disease called Werdnig-Hoffmann disease. Spiridonov has been left paralysed and wheelchair bound by this illness. He suffers from extreme spinal curvature. His health is extremely poor, and in rapid decline. He remains optimistic though. In an interview, he said that he doesn’t view his role as that of a patient. Yes, he has a serious illness that could kill him, but first and foremost, Spiridonov views himself as a scientist, and while he is not “rushing to go under the surgeon’s knife,” he is keen to persuade people that such a surgery is not only possible but necessary, and volunteering himself is probably the only viable way of persuading anyone.

The ethics of this surgery are questionable at best. There hasn’t been a huge amount of research, and the experiments that have taken place have all either been condemned as unethical and barbaric, or their veracity has been called into question. The overwhelming majority of scientists and doctors are in agreement that a head transplant will not work. One surgeon even said that Spiridonov was likely to suffer a fate worse than death.

With the surgery scheduled to take place in only a little over a year, it almost seems impossible that it will even take place. Indeed, even with Spiridonov’s full consent, it seems immoral to go ahead until more research and experimentation takes place.

Canavero has made huge leaps in his field. He introduced a pioneering surgical treatment for Parkinson’s disease, stroke recovery, and patients in a vegetative state. He has published over 100 peer-reviewed papers, and several books. There is no doubt that he is an extremely accomplished scientist and doctor, but a head transplant seems like a step too far, and certainly does not appear possible with modern technology and techniques.