29 October 2021

Head transplant

Reality, fiction and Science

Lyubov Sokovikova, Hi-News.ru

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In the animated series "Futurama", the living heads of politicians, scientists and cultural figures are stored in museums in special banks. But a head transplant (as well as other body parts) in the year 3000 is a common thing, and Dr. Zoidberg somehow sews two heads to one body (while repairing the second one). But is something like this possible in the future? To answer this question, it is worth taking a closer look at the topic. After all, organ transplantation was once considered impossible. And as medical science develops, a head transplant may take place one day. Theoretically, such an operation would involve surgical removal of the head of a person with an incurable disease and the attachment of his blood vessels, muscles, trachea and esophagus to these structures of the donor body. The most recent head transplant procedure proposed by scientists also involves the fusion of the spinal nerves of the recipient and the donor. Subsequent spinal surgery and possibly extensive physical therapy could ideally restore both sensation and motor functions. However, functions such as breathing and eating must be temporarily supported by a ventilator and feeding tube before connections between the brain and body can be adequately restored.

When does death occur?

Before discussing all the subtleties of such a complex medical operation as a head transplant, you should first define death. In 1968, a Harvard committee was tasked with determining when death occurs. The conclusion was that if a person has no detectable brain activity according to a number of criteria, then that person is dead.

This definition, however, has been the subject of several legal disputes, for example, in the case of Jahi Makmat, a 13-year-old girl who had severe blood loss after surgery on tonsils and adenoids, which deprived her brain of oxygen. She was hooked up to a ventilator, but was soon declared brain dead.

The girl's mother refused to accept the doctors' statement – Jahi's heart was beating normally. But the hospital insisted on disconnecting from life support. A lawsuit ensued, and the mother eventually found an institution in New Jersey that accepted Jahi and kept her on a ventilator until the girl died five years later without showing any brain activity.

This case raises important questions. How can someone be dead in one part of the body and not in another? And what about those who believe that science will find a way to revive the brain while the body remains alive.

From organ transplants to head transplants

In 1967, American neurosurgeon Robert White demonstrated that cooling the brain gives surgeons more time to perform successful operations. But they remember him, nevertheless, for something else. In the history of White as the man who first transplanted the head of a monkey.

Surprisingly, the transplanted head remained functional for eight days and even tried to bite White's finger, apparently remembering his tormentor. The experiment made the neurosurgeon think about transplanting a human head. Perhaps this would allow the brain to survive after the rest of the body's organs failed.

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Dr. Robert White in the Brain Research Laboratory.

Interestingly, White considered the British theoretical physicist Stephen Hawking to be the ideal candidates for such an experiment. A head containing a brilliant brain could live on, attached to a new body after his own had ceased to function. White died in 2010 and, they say, even experimented with head transplants on corpses (brrr!).

But despite the many ethical (and medical) issues surrounding such experiments, limited success has been achieved in head transplant procedures on mice, dogs and monkeys. However, it should be noted that many surgeons are critical of the current level of success achieved in animal models.

Moreover, the medical community has questioned whether the methods are sufficiently developed to practically or ethically perform a human head transplant. The effectiveness of using a donor body for a single recipient, rather than for multiple organ transplantation, was also disputed. But surgeons such as Sergio Canavero and Xiaoping Ren plan to perform the first human head transplant in the coming years.

Criteria for a head transplant

In general, a head transplant is indicated when the human brain is functioning normally, unlike the body. It is important to note that scientists do not plan to transplant heads to prolong someone's life when the body fails as a result of natural aging processes.

Young people can be considered as candidates if they have suffered an acute spinal cord injury or have a progressive degenerative disease that does not affect the brain. People with inoperable or advanced forms of cancer that have not metastasized to the brain may also be considered as candidates.

Anomalies affecting the brain are likely to be an exclusion criterion. A person who has undergone a head transplant will need a lot of social support, including continuous medical care and assistance in everyday life for months, if not years," the researchers note.

In fact, it is difficult to predict who may or may not be the ideal candidate for a head transplant. These criteria will be developed after the procedure is implemented and all potential risks of complications and failures are known.

A head transplant is the last hope and can only be used in cases where other medical interventions are unsuccessful.

Before the operation

So, in order to perform a head transplant, it is necessary to make sure that the operation is really necessary and safe and that the recipient of the donor body is likely to achieve long-term success. A systematic assessment of the state of health may be important for identifying chronic diseases that may affect the success of transplantation. Surgeons interested in carrying out the procedure have also prepared protocols planning the stages of future transplantation.

For example, testing for chronic infections, diabetes, thyroid dysfunction and other abnormalities may be required. It may be important to exclude those who smoke, drink alcohol or other prohibited substances, the researchers write.

Other medical experts, on the contrary, criticize the significance or relevance of such experimental studies, since surgical precedents established on animals are not always applicable to human surgery. Moreover, many of the planned tools and methods have not yet been sufficiently studied for their appropriate use.

Ethical issues

For example, futurologist Danila Medvedev and entrepreneur Pyotr Kondaurov were scheduled to speak in Moscow on October 19. Their story at the Biohacking Conference was supposed to be dedicated to transplantology, including head transplantation. After all, back in the 50s, the Soviet and Russian biologist Vladimir Demikhov conducted experiments on planting the heads of one animal to another.

Their lecture never took place. Apparently, there were people who were not ready for such experiments and lectures, who filed an official complaint and the report was removed from the program. Such an approach can hardly be called scientific, so Kondaurov and Medvedev plan to prove their case by deed.

Among those who are regularly attacked by the public is the previously mentioned surgeon Sergio Canavero.

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He plans to perform a human head transplant, probably in China. Yes, it looks like some kind of creepy experiment by a mad scientist, but then again, organ transplantation was once considered impossible.

To date, Canavero has successfully transplanted the heads of bats, but the monkey's head transplant was unsuccessful. After the operation, the monkey was in terrible agony and the animal had to be euthanized 20 hours after the operation. Canavero had previously stated that the world's first head transplant would take place in 2017 or 2018, but, as you can see, the scientist was mistaken in his assumptions.

Interestingly, in November 2017, a successful human head transplant was performed in China. However, an experiment was conducted on dead bodies.  

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