Head transplants more science than fiction

A new surgery could make it possible to transplant a head onto another person’s body within the next two years. The question is, if feasible, how realistic or ethical is this surgery?

A human head transplant may sound as though it belongs in the realms of sci-fi but the concept will be presented later this year at a surgical conference in the US. The aim is to pitch the new procedure to surgeons of the annual conference of the American Academy of Neurological and Orthopaedic Surgeons (AANOS), in an attempt to gather support for the surgery to be developed.

Head transplants were initially suggested in 2013, by Sergio Canavero of the Turin Advanced Neuromodulation Group in Italy. The process combines a donor body, from someone deemed ‘brain dead’, with a ‘working’ head. If successful, the procedure could be used to extend the lives of those who suffer muscle and nerve degeneration.

An early attempt at a head transplant was attempted by Soviet surgeon Vladimir Demikhov in 1954. The procedure involved transplanting a puppy’s head and forelegs onto the back of a larger dog, though the dogs only survived six days.

In the 1970s a team in Cleveland, Ohio, transplanted the head of one monkey onto the body of another. Once again the animal only lived for nine days as the immune system rejected the ‘new’ head.

Since then, there have been few attempts at head transplants. Canavero believes that developments in surgical techniques make it feasible to overcome the roadblocks that have previously limited the development of this surgery.

Earlier this year, he released an outline for the surgical procedure. The first step involves cooling both the recipient’s head and the donor body. The cooling process is essential to extend the time the cells are able to survive without oxygen. The neck and major blood vessels of the recipient are then dissected; the vessels are then connected to the donor body via a series of small tubes. Following this, the spinal cord of each person is severed and the recipients head moved onto the donor body. The two ends of the spinal cord are then fused together, achieved by washing the surface of the spinal cord with the chemical polyethylene glycol. It is hoped that polyethylene glycol will cause the growth of spinal cord nerves. Finally, the muscles and blood vessels are stitched together and the recipient is placed in a coma for three weeks so movement does not damage the spinal cord.

Canavero claims that when the patient regains consciousness, they will have the ability to move and feel their face as well as speak with the same voice as before. He predicts that following physiotherapy, the person would be able to walk within a year.

This radical idea has been met with some scepticism. Polyethylene glycol could fuse the spinal cords, but there is no guarantee that the connectivity between the brain and spinal cord will be fully functional. Canavero has faced this criticism by highlighting that polyethylene is just one method by which they could fuse the spinal cords, and that other options are viable. For example, injection of stem cells or cells of the stomach membrane, shown to help people walk after a spinal injury, could promote spinal nerve growth allowing the cords to fuse.

Another problem associated with this kind of surgery is the risk that the body’s immune system could reject the new head. However, advances in drugs make it possible to manage the immune system in a way that would allow the acceptance of the new head. Despite the ability to overcome the technical aspects of such a major surgery, one of the greatest controversies arises when considering the ethics and approval of such a radical surgery.

Canavero states that ideally he would perform the experimental procedure in the US but believes he is more likely to gain approval in Europe. He understands that there will be many people who disagree with the idea. The ethical implications of this surgery stem from how the human life is defined. One theory suggests that a human is defined by what is contained within the higher cortex. Therefore, as this surgery does not alter the cortex, it could be argued that you are not altering what defines the individual.

The cultural impacts of such a procedure also need to be considered. For example, the belief that a human soul is not confined to the brain would conflict with the approval of a head transplant. There are also concerns about the abuse of such a radical surgery for cosmetic reasons. But if a head transplant were to take place, it would be a rare event and only used in extreme circumstances. If someone wanted to undergo this surgery for superficial reasons, such as ageing or wanting a better body, the surgery would never be considered.

The surgical community has met the idea with heavy criticism; they consider the idea to be too extreme to be of serious consideration. Nonetheless, Canavero is presenting his idea at the AANOS conference later this year where it will be assessed by top international surgeons. Canavero himself understands how radical this procedure is, and states that he won’t go ahead with the idea if society doesn’t want it.

Steven Gibney

Image: Sam Broadley

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